Hyperventilation-induced respiratory alkalosis falls short of countering fatigue during repeated maximal isokinetic contractions.

PubMed

Sakamoto, Akihiro; Naito, Hisashi; Chow, Chin Moi

2015-07-01

Hyperventilation, implemented during recovery of repeated maximal sprints, has been shown to attenuate performance decrement. This study evaluated the effects of hyperventilation, using strength exercises, on muscle torque output and EMG amplitude. Fifteen power-trained athletes underwent maximal isokinetic knee extensions consisting of 12 repetitions × 8 sets at 60°/s and 25 repetitions × 8 sets at 300°/s. The inter-set interval was 40 s for both speeds. For the control condition, subjects breathed spontaneously during the interval period. For the hyperventilation condition, subjects hyperventilated for 30 s before each exercise set (50 breaths/min, PETCO2: 20-25 mmHg). EMG was recorded from the vastus medialis and lateralis muscles to calculate the mean amplitude for each contraction. Hyperventilation increased blood pH by 0.065-0.081 and lowered PCO2 by 8.3-10.3 mmHg from the control values (P < 0.001). Peak torque declined with repetition and set numbers for both speeds (P < 0.001), but the declining patterns were similar between conditions. A significant, but small enhancement in peak torque was observed with hyperventilation at 60°/s during the initial repetition phase of the first (P = 0.032) and fourth sets (P = 0.040). EMG amplitude also declined with set number (P < 0.001) for both speeds and muscles, which was, however, not attenuated by hyperventilation. Despite a minor ergogenic effect in peak torque at 60°/s, hyperventilation was not effective in attenuating the decrement in torque output at 300°/s and decrement in EMG amplitude at both speeds during repeated sets of maximal isokinetic knee extensions.

Impact of hyperventilation on stimulus efficiency during the early phase of an electroconvulsive therapy course: a randomized double-blind study.

PubMed

Mayur, Prashanth; Bray, Amanda; Fernandes, Joanne; Bythe, Karen; Gilbett, David

2010-06-01

The question whether hyperventilation during electroconvulsive therapy (ECT) can improve stimulus efficiency is as yet unanswered. Twenty-five consecutive consenting patients (N = 25) with major depression who were administered ECT entered into the study. Right unilateral ECT at thrice the threshold dose was administered using Mecta spECTrum 5000Q (Mecta Corp, Lake Oswego, Ore), with standard titration procedures and stimulus configurations. At the second ECT session, they were randomly allocated to ECT either with hyperventilation or with no hyperventilation. Hyperventilation was actively administered by an anesthetist just after anesthetic paralysis and before the ECT stimulus during the second, third, and fourth ECT sessions. Assessments were double-blind and performed at baseline and 24 to 48 hours after the fourth ECT session. Time to reorient after ECT was assessed during the first up to the fourth ECT session. Ictal electroencephalogram (EEG) quality was visually assessed using standard scales. There were no significant differences across the 2 groups about depression severity and global cognitive impact. However, the orientation time was 34% longer among those who did not receive hyperventilation. The ratio of orientation time without hyperventilation to that with hyperventilation equals 1.34 (95% confidence interval, 0.94-1.92; P = 0.103). There was a significant increase in threshold over time across both groups (mean difference, 16.4; SE, 5.5; P = 0.006) with no significant main effect for the groups (P = 0.399). There were no significant group differences in the EEG quality. The addition of hyperventilation during the early phase of the ECT course shows a trend to lessen the impact on immediate orientation without impeding clinical response. This does not seem to be mediated by differential threshold changes or change to the ictal EEG quality.

Parental bonding in males with adjustment disorder and hyperventilation syndrome

PubMed Central

2012-01-01

Background The purpose of the study was to identify the style of parental bonding and the personality characteristics that might increase the risk of hyperventilation and adjustment disorder. Methods A total of 917 males were recruited, 156 with adjustment disorder and hyperventilation syndrome (AD + HY), 273 with adjustment disorder without hyperventilation syndrome (AD–HY), and 488 healthy controls. All participants completed the Parental Bonding Instrument, Eysenck Personality Questionnaire, and Chinese Health Questionnaire. Results Analysis using structural equation models identified a pathway relationship in which parental bonding affected personality characteristics, personality characteristics affected mental health condition, and mental health condition affected the development of hyperventilation or adjustment disorder. Males with AD–HY perceived less paternal care, and those with AD + HY perceived more maternal protection than those with adjustment disorder and those in the control group. Participants with AD–HY were more neurotic and less extroverted than those with AD + HY. Both groups showed poorer mental health than the controls. Conclusions Although some patients with hyperventilation syndrome demonstrated symptoms of adjustment disorder, there were different predisposing factors between the two groups in terms of parental bonding and personality characteristics. This finding is important for the early intervention and prevention of hyperventilation and adjustment disorder. PMID:22672223

Primary Hyperventilation in the Emergency Department: A First Overview

PubMed Central

Pfortmueller, Carmen Andrea; Pauchard-Neuwerth, Sandra Elisabeth; Leichtle, Alexander Benedikt; Fiedler, Georg Martin; Exadaktylos, Aristomenis Konstantinos; Lindner, Gregor

2015-01-01

Background Primary hyperventilation is defined as a state of alveolar ventilation in excess of metabolic requirements, leading to decreased arterial partial pressure of carbon dioxide. The primary aim of this study was to characterise patients diagnosed with primary hyperventilation in the ED. Methods Our retrospective cohort study comprised adult (≥16 years) patients admitted to our ED between 1 January 2006 and 31 December 2012 with the primary diagnosis of primary (=psychogenic) hyperventilation. Results A total of 616 patients were eligible for study. Participants were predominantely female (341 [55.4%] female versus 275 [44.6%] male respectively, p <0.01). The mean age was 36.5 years (SD 15.52, range 16-85). Patients in their twenties were the most common age group (181, 29.4%), followed by patients in their thirties (121, 19.6%). Most patients presented at out-of-office hours (331 [53.7%]. The most common symptom was fear (586, 95.1%), followed by paraesthesia (379, 61.5%) and dizziness (306, 49.7%). Almost a third (187, 30.4%) of our patients had previously experienced an episode of hyperventilation and half (311, 50.5%) of patients had a psychiatric co-morbidity. Conclusion Hyperventilation is a diagnostic chimera with a wide spectrum of symptoms. Patients predominantly are of young age, female sex and often have psychiatric comorbidities. The severity of symptoms accompanied with primary hyperventilation most often needs further work-up to rule out other diagnosis in a mostly young population. In the future, further prospective multicentre studies are needed to evaluate and establish clear diagnostic criteria for primary hyperventilation and possible screening instruments. PMID:26110771

Primary Hyperventilation in the Emergency Department: A First Overview.

PubMed

Pfortmueller, Carmen Andrea; Pauchard-Neuwerth, Sandra Elisabeth; Leichtle, Alexander Benedikt; Fiedler, Georg Martin; Exadaktylos, Aristomenis Konstantinos; Lindner, Gregor

2015-01-01

Primary hyperventilation is defined as a state of alveolar ventilation in excess of metabolic requirements, leading to decreased arterial partial pressure of carbon dioxide. The primary aim of this study was to characterise patients diagnosed with primary hyperventilation in the ED. Our retrospective cohort study comprised adult (≥16 years) patients admitted to our ED between 1 January 2006 and 31 December 2012 with the primary diagnosis of primary (=psychogenic) hyperventilation. A total of 616 patients were eligible for study. Participants were predominantely female (341 [55.4%] female versus 275 [44.6%] male respectively, p <0.01). The mean age was 36.5 years (SD 15.52, range 16-85). Patients in their twenties were the most common age group (181, 29.4%), followed by patients in their thirties (121, 19.6%). Most patients presented at out-of-office hours (331 [53.7%]. The most common symptom was fear (586, 95.1%), followed by paraesthesia (379, 61.5%) and dizziness (306, 49.7%). Almost a third (187, 30.4%) of our patients had previously experienced an episode of hyperventilation and half (311, 50.5%) of patients had a psychiatric co-morbidity. Hyperventilation is a diagnostic chimera with a wide spectrum of symptoms. Patients predominantly are of young age, female sex and often have psychiatric comorbidities. The severity of symptoms accompanied with primary hyperventilation most often needs further work-up to rule out other diagnosis in a mostly young population. In the future, further prospective multicentre studies are needed to evaluate and establish clear diagnostic criteria for primary hyperventilation and possible screening instruments.

A Case of Neuro-Behcet’s Disease Presenting with Central Neurogenic Hyperventilation

PubMed Central

Alkhachroum, Ayham M.; Saeed, Saba; Kaur, Jaspreet; Shams, Tanzila; De Georgia, Michael A.

2016-01-01

Patient: Female, 46 Final Diagnosis: Central hyperventilation Symptoms: Hyperventilation Medication: — Clinical Procedure: None Specialty: Neurology Objective: Unusual clinical course Background: Behcet’s disease is a chronic inflammatory disorder usually characterized by the triad of oral ulcers, genital ulcers, and uveitis. Central to the pathogenesis of Behcet’s disease is an autoimmune vasculitis. Neurological involvement, so called “Neuro-Behcet’s disease”, occurs in 10–20% of patients, usually from a meningoencephalitis or venous thrombosis. Case Report: We report the case of a 46-year-old patient with Neuro-Behcet’s disease who presented with central neurogenic hyperventilation as a result of brainstem involvement from venulitis. Conclusions: To the best of our knowledge, central neurogenic hyperventilation has not previously been described in a patient with Neuro-Behcet’s disease. PMID:26965646

Characteristics of hyperthermia-induced hyperventilation in humans

PubMed Central

Tsuji, Bun; Hayashi, Keiji; Kondo, Narihiko; Nishiyasu, Takeshi

2016-01-01

ABSTRACT In humans, hyperthermia leads to activation of a set of thermoregulatory responses that includes cutaneous vasodilation and sweating. Hyperthermia also increases ventilation in humans, as is observed in panting dogs, but the physiological significance and characteristics of the hyperventilatory response in humans remain unclear. The relative contribution of respiratory heat loss to total heat loss in a hot environment in humans is small, and this hyperventilation causes a concomitant reduction in arterial CO2 pressure (hypocapnia), which can cause cerebral hypoperfusion. Consequently, hyperventilation in humans may not contribute to the maintenance of physiological homeostasis (i.e., thermoregulation). To gain some insight into the physiological significance of hyperthermia-induced hyperventilation in humans, in this review, we discuss 1) the mechanisms underlying hyperthermia-induced hyperventilation, 2) the factors modulating this response, and 3) the physiological consequences of the response. PMID:27227102

Effect of voluntary hypocapnic hyperventilation on the relationship between core temperature and heat loss responses in exercising humans.

PubMed

Fujii, Naoto; Honda, Yasushi; Komura, Ken; Tsuji, Bun; Sugihara, Akira; Watanabe, Kazuhito; Kondo, Narihiko; Nishiyasu, Takeshi

2014-12-01

Two thermolytic thermoregulatory responses, cutaneous vasodilation and sweating, begin when core temperature reaches a critical threshold, after which response magnitudes increase linearly with increasing core temperature; thus the slope indicates response sensitivity. We evaluated the influence of hypocapnia induced by voluntary hyperventilation on the core temperature threshold and sensitivity of thermoregulatory responses. Ten healthy males performed 15 min of cycling at 117 W (29.5°C, 50% RH) under three breathing conditions: 1) spontaneous ventilation, 2) voluntary normocapnic hyperventilation, and 3) voluntary hypocapnic hyperventilation. In the hypocapnic hyperventilation trial, end-tidal CO2 pressure was reduced throughout the exercise, whereas it was maintained around the normocapnic level in the other two trials. Cutaneous vascular conductances at the forearm and forehead were evaluated as laser-Doppler signal/mean arterial blood pressure, and the forearm sweat rate was measured using the ventilated capsule method. Esophageal temperature threshold was higher for the increase in cutaneous vascular conductance in the hypocapnic than normocapnic hyperventilation trial at the forearm (36.88 ± 0.36 vs. 36.68 ± 0.34°C, P < 0.05) and forehead (36.89 ± 0.31 vs. 36.75 ± 0.31°C, P < 0.05). The slope relating esophageal temperature to cutaneous vascular conductance was decreased in the hypocapnic than normocapnic hyperventilation trial at the forearm (302 ± 177 vs. 420 ± 178% baseline/°C, P < 0.05) and forehead (236 ± 164 vs. 358 ± 221% baseline/°C, P < 0.05). Neither the threshold nor the slope for the forearm sweat rate differed significantly between the hypocapnic or normocapnic hyperventilation trials. These findings indicate that in exercising humans, hypocapnia induced by voluntary hyperventilation does not influence sweating, but it attenuates the cutaneous vasodilatory response by increasing its threshold and reducing its sensitivity. Copyright © 2014 the American Physiological Society.

Hyperventilation with and without maintenance of isocapnia: a comparison of selected gasometric and respiratory parameters.

PubMed

Sein Anand, Jacek; Wiśniewski, Marek; Waldman, Wojciech

2014-09-15

The aims of this study were to examine selected respiratory and gasometric parameters during hyperventilation with and without isocapnia and to identify the possible mechanism by which isocapnic hyperventilation might be useful in the elimination of volatile substances, including CO. Ten healthy non-smoking volunteers were studied, and each underwent two procedures. During one session, CO2 was added to the respiratory circuit, and during the other session, only 100% O2 was used. The volunteers were coached to hyperventilate until the appearance of side effects. Isocapnic hyperventilation significantly increased alveolar minute ventilation and partial pressure of oxygen in arterialized capillary blood (paO2); to the best of our knowledge, these findings have not previously been reported. Isocapnic hyperventilation was associated with only mild side effects, such as dyspnea, increased respiratory effort and headache, in 30% of subjects. Side effects, including vertigo, paresthesias and muscle tremor, were present in 70% of the volunteers during hyperventilation with 100% O2, and these side effects forced them to limit their respiratory rates and tidal volumes. These increases in alveolar ventilation and the partial pressure of oxygen in the blood may play crucial roles in decreasing the half-time of carboxyhemoglobin, which is the primary goal of the treatment of CO poisoning. Copyright © 2014 Elsevier B.V. All rights reserved.

Hypercapnic hyperventilation shortens emergence time from isoflurane anesthesia.

PubMed

Sakata, Derek J; Gopalakrishnan, Nishant A; Orr, Joseph A; White, Julia L; Westenskow, Dwayne R

2007-03-01

To shorten emergence time after a procedure using volatile anesthesia, 78% of anesthesiologists recently surveyed used hyperventilation to rapidly clear the anesthetic from the lungs. Hyperventilation has not been universally adapted into clinical practice because it also decreases the Paco2, which decreases cerebral bloodflow and depresses respiratory drive. Adding deadspace to the patient's airway may be a simple and safe method of maintaining a normal or slightly increased Paco2 during hyperventilation. We evaluated the differences in emergence time in 20 surgical patients undergoing 1 MAC of isoflurane under mild hypocapnia (ETco2 approximately 28 mmHg) and mild hypercapnia (ETco2 approximately 55 mmHg). The minute ventilation in half the patients was doubled during emergence, and hypercapnia was maintained by insertion of additional airway deadspace to keep the ETco2 close to 55 mmHg during hyperventilation. A charcoal canister adsorbed the volatile anesthetic from the deadspace. Fresh gas flows were increased to 10 L/min during emergence in all patients. The time between turning off the vaporizer and the time when the patients opened their eyes and mouths, the time of tracheal extubation, and the time for normalized bispectral index to increase to 0.95 were faster whenever hypercapnic hyperventilation was maintained using rebreathing and anesthetic adsorption (P < 0.001). The time to tracheal extubation was shortened by an average of 59%. The emergence time after isoflurane anesthesia can be shortened significantly by using hyperventilation to rapidly clear the anesthetic from the lungs and CO2 rebreathing to induce hypercapnia during hyperventilation. The device should be considered when it is important to provide a rapid emergence, especially after surgical procedures where a high concentration of the volatile anesthetic was maintained right up to the end of the procedure, or where surgery ends abruptly and without warning.

The association of panic and hyperventilation with psychogenic non-epileptic seizures: A systematic review and meta-analysis.

PubMed

Indranada, Alaric M; Mullen, Saul A; Duncan, Roderick; Berlowitz, David J; Kanaan, Richard A A

2018-07-01

Psychogenic Non-Epileptic Seizures (PNES) are events that appear epileptic but are instead thought to have a psychological origin. Increased rates of several psychiatric disorders have been reported in PNES, including anxiety and panic disorders. Some theories suggest panic and/or hyperventilation have aetiological roles in PNES, though these remain unproven. We conducted a systematic review of associations of panic and hyperventilation with PNES using Ovid Medline and PubMed, and a meta-analysis where appropriate. We found eighteen studies reporting rates of panic in PNES and eight studies reporting hyperventilation. The reported rate of panic attacks in PNES ranged from 17% to 83%, with physical symptoms more commonly reported, and affective symptoms less so. 'Dizziness or light-headedness' was found to be more prevalent than 'fear of dying' by random-effects meta-analysis (68% vs. 23%). A proportion meta-analysis found a weighted occurrence of 20% of panic disorder in PNES. A pooled meta-analytic rate of PNES events following voluntary hyperventilation induction was 30%, while the clinically observed rates of peri-ictal hyperventilation in PNES without induction varied from 15 to 46%. Previous studies have reported moderate rates of association of panic in PNES, though the proportions varied considerably across the literature, with physical symptoms more commonly reported than affective. Hyperventilation is an effective inducer of PNES events in a minority, and can be observed occurring in a minority of patients without induction. These results support an important, albeit not essential, role for panic and hyperventilation in the pathogenesis of PNES events. Copyright © 2018 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

Elevated lactate during psychogenic hyperventilation.

PubMed

ter Avest, E; Patist, F M; Ter Maaten, J C; Nijsten, M W N

2011-04-01

Elevated arterial lactate levels are closely related to morbidity and mortality in various patient categories. In the present retrospective study, the relation between arterial lactate, partial pressure of carbon dioxide (Pco(2)) and pH was systematically investigated in patients who visited the emergency department (ED) with psychogenic hyperventilation. Over a 5-month period, all the patients who visited the ED of a university hospital with presumed psychogenic hyperventilation were evaluated. Psychogenic hyperventilation was presumed to be present when an increased respiratory rate (>20 min) was documented at or before the ED visit and when somatic causes explaining the hyperventilation were absent. Arterial blood gas and lactate levels (reference values 0.5-1.5 mmol/l) were immediately measured by a point-of-care analyser that was managed and calibrated by the central laboratory. During the study period, 46 patients were diagnosed as having psychogenic hyperventilation. The median (range) Pco(2) for this group was 4.3 (2.0-5.5) kPa, the pH was 7.47 (7.40-7.68) and the lactate level was 1.2 (0.5-4.4) mmol/l. 14 participants (30%) had a lactate level above the reference value of 1.5 mmol/l. Pco(2) was the most important predictor of lactate in multivariate analysis. None of the participants underwent any medical treatment other than observation at the ED or had been hospitalised after their ED visit. In patients with psychogenic hyperventilation, lactate levels are frequently elevated. Whereas high lactates are usually associated with acidosis and an increased risk of poor outcome, in patients with psychogenic hyperventilation, high lactates are associated with hypocapnia and alkalosis. In this context, elevated arterial lactate levels should not be regarded as an adverse sign.

Hyperventilation as a strategy for improved repeated sprint performance.

PubMed

Sakamoto, Akihiro; Naito, Hisashi; Chow, Chin-Moi

2014-04-01

Repeated high-intensity sprints incur substantial anaerobic metabolic challenges and create an acidic muscle milieu that is unfavorable for subsequent performance. Hyperventilation, resulting in respiratory alkalosis, acts as a compensatory mechanism for metabolic acidosis. This study tested the hypothesis that hyperventilation performed during recovery intervals would attenuate performance decrement in repeated sprint pedaling. Thirteen male university athletes performed 10 sets of 10-second maximal pedaling on a cycle ergometer with a 60-second recovery between sets under control (spontaneous breathing) and hyperventilation conditions in a crossover counter-balanced manner. Pedaling load was set at 0.075 × body mass. Peak and mean power outputs were documented for each set to compare performance decrements for 10 sets between conditions. Hyperventilation (60 breaths per minute and end-tidal partial pressure of CO2 maintained at 20-25 mm Hg) was performed 30 seconds before each sprint set. This intervention successfully increased blood pH by 0.03-0.07 but lowered P(CO2) by 1.2-8.4 mm Hg throughout exercise (p < 0.001). The peak and mean power outputs, and blood [La] accumulation were not significantly different between the conditions. However, a significant condition × time interaction existed for peak power (p = 0.035) and mean power (p = 0.023), demonstrating an attenuation in power decrement in later sprint sets with hyperventilation. In conclusion, hyperventilation implemented during recovery intervals of repeated sprint pedaling attenuated performance decrements in later exercise bouts that was associated with substantial metabolic acidosis. The practical implication is that hyperventilation may have a strategic role for enhancing training effectiveness and may give an edge in performance outcomes.

Cerebral metabolic rate of oxygen (CMRO2 ) mapping with hyperventilation challenge using quantitative susceptibility mapping (QSM).

PubMed

Zhang, Jingwei; Zhou, Dong; Nguyen, Thanh D; Spincemaille, Pascal; Gupta, Ajay; Wang, Yi

2017-05-01

Our objective was to demonstrate the feasibility of using hyperventilation as an efficient vasoconstrictive challenge and prior knowledge as denoising constraints for cerebral metabolic rate of oxygen (CMRO 2 ) mapping based upon quantitative susceptibility mapping (QSM). Three-dimensional (3D) multi-echo gradient echo and arterial spin labeling imaging were performed to calculate QSM and perfusion maps before and after a hyperventilation challenge in 11 healthy subjects. For comparison, this was repeated using a caffeine challenge. Whole-brain CMRO 2 and oxygen extraction fraction (OEF) maps were computed using constrained optimization. Hyperventilation scans were repeated to measure reproducibility. Regional agreement of CMRO 2 and OEF maps was analyzed within the cortical gray matter (CGM) using t-test and Bland-Altman plots. Hyperventilation challenge eliminates the 30-min waiting time needed for caffeine to exert its vasoconstrictive effects. Mean CMRO 2 (in µmol/100g/min) obtained in CGM using the caffeine and repeated hyperventilation scans were 149 ± 16, 153 ± 19, and 150 ± 20, respectively. This corresponded to an OEF of 33.6 ± 3.4%, 32.3 ± 3.2%, and 34.1 ± 3.8% at baseline state and 39.8 ± 4.8%, 43.6 ± 6.2%, and 42.8 ± 6.8% at challenged state, respectively. Hyperventilation scans produced a good agreement of CMRO 2 and OEF values. Hyperventilation is a feasible, reproducible, and efficient vasoconstrictive challenge for QSM-based quantitative CMRO 2 mapping. Magn Reson Med 77:1762-1773, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Hyperventilation-induced nystagmus in vestibular schwannoma and unilateral sensorineural hearing loss.

PubMed

Mandalà, Marco; Giannuzzi, Annalisa; Astore, Serena; Trabalzini, Franco; Nuti, Daniele

2013-07-01

We evaluated the incidence and characteristics of hyperventilation-induced nystagmus (HVN) in 49 patients with gadolinium-enhanced magnetic resonance imaging evidence of vestibular schwannoma and 53 patients with idiopathic unilateral sensorineural hearing loss and normal radiological findings. The sensitivity and specificity of the hyperventilation test were compared with other audio-vestibular diagnostic tests (bedside examination of eye movements, caloric test, auditory brainstem responses) in the two groups of patients. The hyperventilation test scored the highest diagnostic efficiency (sensitivity 65.3 %; specificity 98.1 %) of the four tests in the differential diagnosis of vestibular schwannoma and idiopathic unilateral sensorineural hearing loss. Small tumors with a normal caloric response or caloric paresis were associated with ipsilateral HVN and larger tumors and severe caloric deficits with contralateral HVN. These results confirm that the hyperventilation test is a useful diagnostic test for predicting vestibular schwannoma in patients with unilateral sensorineural hearing loss.

Hyperventilation and Raynaud's disease.

PubMed Central

Williams, H.; Freeman, L. J.; Nixon, P. G.

1987-01-01

A 42 year old woman with long standing Raynaud's disease, unresponsive to medical and surgical treatment, was noted to have a typical history of the hyperventilation syndrome. Rewarming of the hands following cold challenge was markedly prolonged in the presence of hypocapnia. It is suggested that hyperventilation may have an aetiological role in maintaining digital artery spasm in Raynaud's disease, which would benefit from recognition and treatment. PMID:3671272

Hyperventilation and aerophagia: a negative report.

PubMed

Folgering, H; Sistermans, H

1986-03-01

Aerophagia is described as a frequent symptom in the hyperventilation syndrome. However, this has never been substantiated. In this study the extent of air swallowing was estimated from the size of the gastric air-bubble on the chest X-ray, in a group of 62 hyperventilators and in a group of 62 normals. No differences were found between the mean amounts of gastric air in the two groups. Women in both groups seemed to swallow more air than men. The amount of air was not related to the time of the day (meals). In 15 hyperventilators the subjective complaints of upper abdominal discomfort and of chest pain were quantified: no correlation was found with the amount of gastric air.

Responses to voluntary hyperventilation in children with separation anxiety disorder: implications for the link to panic disorder.

PubMed

Kossowsky, Joe; Wilhelm, Frank H; Schneider, Silvia

2013-10-01

Biological theories on respiratory regulation have linked separation anxiety disorder (SAD) to panic disorder (PD). We tested if SAD children show similarly increased anxious and psychophysiological responding to voluntary hyperventilation and compromised recovery thereafter as has been observed in PD patients. Participants were 49 children (5-14 years old) with SAD, 21 clinical controls with other anxiety disorders, and 39 healthy controls. We assessed cardiac sympathetic and parasympathetic, respiratory (including pCO2), electrodermal, electromyographic, and self-report variables during baseline, paced hyperventilation, and recovery. SAD children did not react with increased anxiety or panic symptoms and did not show signs of slowed recovery. However, during hyperventilation they exhibited elevated reactivity in respiratory variability, heart rate, and musculus corrugator supercilii activity indicating difficulty with respiratory regulation. Reactions to hyperventilation are much less pronounced in children with SAD than in PD patients. SAD children showed voluntary breathing regulation deficits. Copyright © 2013 Elsevier Ltd. All rights reserved.

Optimized hyperventilation preserves 2,3-diphosphoglycerate in severe traumatic brain injury.

PubMed

Torres, Rayne Borges; Terzi, Renato Giuseppe Giovanni; Falcão, Antônio Luís Eiras; Höehr, Nelci Fenalti; Dantas Filho, Venâncio Pereira

2007-09-01

The concentration of 2,3-diphosphoglycerate (2,3-DPG/Hct) increases as a physiological occurrence to pH increase and hyperventilation. This response was tested in patients with severe traumatic brain injury (TBI). The concentration of 2,3-DPG/Hct was measured daily for six days in eleven patients with severe TBI in need of optimized hyperventilation because of intracranial hypertension. There was correlation between pH and the concentration of DPG/Hct. The concentration of 2,3-DPG/Hct remained predominantly within normal levels with slight increase in the sixth day of the study. The concentration of 2,3-DPG/Hct correlated significantly with measured partial pressure of oxygen that saturates 50% the hemoglobin of the blood (P50st), confirming the consistency of our data. The expected physiological response of a progressive increase in concentration of 2,3-DPG/Hct to hyperventilation was not observed. This fact may be explained by the intermittent and not sustained hyperventilation as dictated by the protocol of optimized ventilation.

Correlation Between Capnography and Arterial Carbon Dioxide Before, During, and After Severe Chest Injury in Swine

DTIC Science & Technology

2012-01-01

In addi- tion to securing a patent airway, first responders must attempt to achieve adequate ventilation, as hyperventilation or hypo- ventilation... hyperventilated or hypoventi- lated (n = 890 intubated and n = 2,709 nonintubated) before hospital arrival. Adverse effects of ventilation are especially...perfusion, whereas hypoventila- tion causes decreased oxygen delivery (3, 4). Additional risks associated with hyperventilation include overinflation of

Mapping Transient Hyperventilation Induced Alterations with Estimates of the Multi-Scale Dynamics of BOLD Signal.

PubMed

Kiviniemi, Vesa; Remes, Jukka; Starck, Tuomo; Nikkinen, Juha; Haapea, Marianne; Silven, Olli; Tervonen, Osmo

2009-01-01

Temporal blood oxygen level dependent (BOLD) contrast signals in functional MRI during rest may be characterized by power spectral distribution (PSD) trends of the form 1/f(alpha). Trends with 1/f characteristics comprise fractal properties with repeating oscillation patterns in multiple time scales. Estimates of the fractal properties enable the quantification of phenomena that may otherwise be difficult to measure, such as transient, non-linear changes. In this study it was hypothesized that the fractal metrics of 1/f BOLD signal trends can map changes related to dynamic, multi-scale alterations in cerebral blood flow (CBF) after a transient hyperventilation challenge. Twenty-three normal adults were imaged in a resting-state before and after hyperventilation. Different variables (1/f trend constant alpha, fractal dimension D(f), and, Hurst exponent H) characterizing the trends were measured from BOLD signals. The results show that fractal metrics of the BOLD signal follow the fractional Gaussian noise model, even during the dynamic CBF change that follows hyperventilation. The most dominant effect on the fractal metrics was detected in grey matter, in line with previous hyperventilation vaso-reactivity studies. The alpha was able to differentiate also blood vessels from grey matter changes. D(f) was most sensitive to grey matter. H correlated with default mode network areas before hyperventilation but this pattern vanished after hyperventilation due to a global increase in H. In the future, resting-state fMRI combined with fractal metrics of the BOLD signal may be used for analyzing multi-scale alterations of cerebral blood flow.

Hypocapnia and hyperoxia induction using a hyperventilation protocol in electroconvulsive therapy.

PubMed

de Arriba-Arnau, Aida; Dalmau, Antonia; Salvat-Pujol, Neus; Soria, Virginia; Bocos, Javier; Menchón, José Manuel; Urretavizcaya, Mikel

Hyperventilation in electroconvulsive therapy sessions has been associated with seizure threshold, seizure characteristics, and cognitive effects. There is no consensus on the optimal procedure of applying hyperventilation manoeuvres during electroconvulsive therapy. Prospective evaluation of the effects of systematic use of hyperventilation manoeuvres with facial mask and capnography (protocolized hyperventilation [pHV]), on ventilation parameters and on seizures. The study included a sample of 130 sessions (65 performed according to hyperventilation standard practice and 65 successive sessions, with pHV) of 35 patients over a period of 10 weeks. The pHV manoeuvres reduced exhaled CO 2 and increased O 2 saturation significantly (P<.001). The average CO 2 reduction achieved was 6.52±4.75mmHg (95% CI -7.7 to -5.3). The CO 2 values after pHV correlated significantly with seizure duration and O 2 values, with other electroencephalographic quality indices. In pHV sessions, compared with sessions performed according to hyperventilation standard practice, the average lengthening of the motor and electroencephalographic seizure was 3.86±14.62 and 4.73±13.95s, respectively. No differences were identified in other ictal quality parameters. The proposed pHV manoeuvres significantly modify ventilation parameters. The hypocapnia and hyperoxia obtained by applying these manoeuvres lengthen the duration of seizures without worsening the quality of the electroencephalographic trace. The use of pHV is generalisable and might improve electroconvulsive therapy procedure without adding costs. Copyright © 2016 SEP y SEPB. Publicado por Elsevier España, S.L.U. All rights reserved.

Protocolized hyperventilation enhances electroconvulsive therapy.

PubMed

de Arriba-Arnau, Aida; Dalmau, Antonia; Soria, Virginia; Salvat-Pujol, Neus; Ribes, Carmina; Sánchez-Allueva, Ana; Menchón, José Manuel; Urretavizcaya, Mikel

2017-08-01

Hyperventilation is recommended in electroconvulsive therapy (ECT) to enhance seizures and to increase patients' safety. However, more evidence is needed regarding its effects and the optimum method of application. This prospective study involving 21 subjects compared two procedures, protocolized hyperventilation (PHV) and hyperventilation as usual (HVau), applied to the same patient in two consecutive sessions. Transcutaneous partial pressure of carbon dioxide (TcPCO 2 ) was measured throughout all sessions. Ventilation parameters, hemodynamic measures, seizure characteristics, and side effects were also explored. PHV resulted in lower TcPCO 2 after hyperventilation (p=.008) and over the whole session (p=.035). The lowest TcPCO 2 was achieved after voluntary hyperventilation. Changes in TcPCO 2 from baseline showed differences between HVau and PHV at each session time-point (all p<.05). Between- and within-subjects factors were statistically significant in a general linear model. Seizure duration was greater in PHV sessions (p=.028), without differences in other seizure quality parameters or adverse effects. Correlations were found between hypocapnia induction and seizure quality indexes. Secondary outcomes could be underpowered. PHV produces hypocapnia before the stimulus, modifies patients' TcPCO 2 values throughout the ECT session and lengthens seizure duration. Voluntary hyperventilation is the most important part of the PHV procedure with respect to achieving hypocapnia. A specific ventilation approach, CO 2 quantification and monitoring may be advisable in ECT. PHV is easy to apply in daily clinical practice and does not imply added costs. Ventilation management has promising effects in terms of optimizing ECT technique. Copyright © 2017 Elsevier B.V. All rights reserved.

Changes in Cerebral Compartmental Compliances during Mild Hypocapnia in Patients with Traumatic Brain Injury

PubMed Central

Steiner, Luzius A.; Castellani, Gianluca; Smielewski, Peter; Zweifel, Christian; Haubrich, Christina; Pickard, John D.; Menon, David K.; Czosnyka, Marek

2011-01-01

Abstract The benefit of induced hyperventilation for intracranial pressure (ICP) control after severe traumatic brain injury (TBI) is controversial. In this study, we investigated the impact of early and sustained hyperventilation on compliances of the cerebral arteries and of the cerebrospinal (CSF) compartment during mild hyperventilation in severe TBI patients. We included 27 severe TBI patients (mean 39.5 ± 3.4 years, 6 women) in whom an increase in ventilation (20% increase in respiratory minute volume) was performed during 50 min as part of a standard clinical CO2 reactivity test. Using a new mathematical model, cerebral arterial compliance (Ca) and CSF compartment compliance (Ci) were calculated based on the analysis of ICP, arterial blood pressure, and cerebral blood flow velocity waveforms. Hyperventilation initially induced a reduction in ICP (17.5 ± 6.6 vs. 13.9 ± 6.2 mmHg; p < 0.001), which correlated with an increase in Ci (r2 = 0.213; p = 0.015). Concomitantly, the reduction in cerebral blood flow velocities (CBFV, 74.6 ± 27.0 vs. 62.9 ± 22.9 cm/sec; p < 0.001) marginally correlated with the reduction in Ca (r2 = 0.209; p = 0.017). During sustained hyperventilation, ICP increased (13.9 ± 6.2 vs. 15.3 ± 6.4 mmHg; p < 0.001), which correlated with a reduction in Ci (r2 = 0.297; p = 0.003), but no significant changes in Ca were found during that period. The early reduction in Ca persisted irrespective of the duration of hyperventilation, which may contribute to the lack of clinical benefit of hyperventilation after TBI. Further studies are needed to determine whether monitoring of arterial and CSF compartment compliances may detect and prevent an adverse ischemic event during hyperventilation. PMID:21204704

Influence of prior hyperventilation duration on respiratory chemosensitivity and cerebrovascular reactivity during modified hyperoxic rebreathing.

PubMed

Boulet, Lindsey M; Tymko, Michael M; Jamieson, Alenna N; Ainslie, Philip N; Skow, Rachel J; Day, Trevor A

2016-07-01

What is the central question of this study? We characterized and compared the cardiorespiratory and cerebrovascular responses to the 'Duffin' modified hyperoxic CO2 rebreathing test by randomly altering the prior hyperventilation duration. What is the main finding and its importance? Our main finding was that prior hyperventilation duration (1, 3 or 5 min) had no effect on cardiorespiratory and cerebrovascular responses to the hyperoxic rebreathing test, within individuals. These findings suggest that the standard 5 min prior hyperventilation duration used to clear body CO2 stores is unnecessary and can reasonably be shortened to 1 min, reducing protocol times and improving participant comfort. The 'Duffin' modified hyperoxic rebreathing test allows investigators to characterize and quantify the ventilatory and cerebrovascular responses to CO2 across a large physiological range, allowing quantification of basal ventilation and the ventilatory recruitment threshold (VRT). Although the standard protocol includes 5 min of prior hyperventilation to clear body CO2 stores, there is no experimental evidence that a full 5 min is required. We hypothesized that there would be no within-individual differences in the cardiorespiratory or cerebrovascular responses to rebreathing with shortened hyperventilation duration prior to hyperoxic rebreathing. Using a rebreathing apparatus, transcranial Doppler ultrasound and beat-to-beat blood pressure monitoring, we tested 19 participants in the supine position using three randomly assigned hyperoxic rebreathing tests with 1, 3 or 5 min of prior hyperventilation. We measured VRT (in Torr CO2 ), time to VRT (in seconds), central respiratory chemoreflex (breathing frequency, tidal volume and minute ventilation), cerebrovascular (middle and posterior cerebral artery velocity) and cardiovascular (heart rate and mean arterial pressure) responses to CO2 during hyperoxic rebreathing. Using linear regression and repeated-measures ANOVAs, we found no differences in any of the cardiorespiratory or cerebrovascular response magnitudes between trials (P > 0.05). The only difference observed was in the time to VRT (in seconds), whereby 1 min prior hyperventilation duration was shorter (135.4 ± 19.7 s) than with 3 or 5 min prior hyperventilation (176.3 ± 15.1 and 187.2 ± 11.6 s, respectively; P < 0.001). Our findings indicate that 5 min of prior hyperventilation is unnecessary during modified rebreathing when using it to quantify respiratory or cerebrovascular responses and can be reasonably shortened to 1 min, reducing protocol times and improving participant comfort. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.

Effects of hyperventilation on cerebral oxygen saturation estimated using near-infrared spectroscopy: A randomised comparison between propofol and sevoflurane anaesthesia.

PubMed

Ishiyama, Tadahiko; Kotoda, Masakazu; Asano, Nobumasa; Ikemoto, Kodai; Shintani, Noriyuki; Matsuoka, Toru; Matsukawa, Takashi

2016-12-01

Near-infrared spectroscopy estimates cerebral regional tissue oxygen saturation (rSO2), which may decrease under hyperventilation. Propofol and sevoflurane act differently on cerebral blood vessels. Consequently, cerebral blood flow during hyperventilation with propofol and sevoflurane anaesthesia may differ. The first aim of this study was to compare the changes in rSO2 between propofol and sevoflurane anaesthesia during hyperventilation. The second aim was to assess changes in rSO2 with ventilation changes. A randomised, open-label study. University of Yamanashi Hospital, Yamanashi, Japan from January 2014 to September 2014. Fifty American Society of Anesthesiologists physical status 1 or 2 adult patients who were scheduled for elective abdominal surgery were assigned randomly to receive either propofol or sevoflurane anaesthesia. Exclusion criterion was a known history of cerebral disease such as cerebral infarction, cerebral haemorrhage, transient ischaemic attack and subarachnoid haemorrhage. After induction of anaesthesia but before the start of surgery, rSO2, arterial carbon dioxide partial pressure (PaCO2) and arterial oxygen saturation were measured. Measurements were repeated at 5-min intervals during 15 min of hyperventilation with a PaCO2 around 30 mmHg (4 kPa), and again after ventilation was normalised. The primary outcome was the difference of changes in rSO2 between propofol anaesthesia and sevoflurane anaesthesia during and after hyperventilation. The second outcome was change in rSO2 after the initiation of hyperventilation and after the normalisation of ventilation. Changes of rSO2 during hyperventilation were -10 ± 7% (left) and -11 ± 8% (right) in the propofol group, and -10 ± 8% (left) and -9 ± 7% (right) in the sevoflurane group. After normalisation of PaCO2, rSO2 returned to baseline values. Arterial oxygen saturation remained stable throughout the measurement period. The rSO2 values were similar in the propofol and the sevoflurane groups at each time point. The effects of hyperventilation on estimated rSO2 were similar with propofol and sevoflurane anaesthesia. Changes in rSO2 correlated well with ventilation changes. Japan Primary Registries Network (JPRN); UMIN-CTR ID; UMIN000010640.

Cerebral hemodynamics at altitude: effects of hyperventilation and acclimatization on cerebral blood flow and oxygenation.

PubMed

Sanborn, Matthew R; Edsell, Mark E; Kim, Meeri N; Mesquita, Rickson; Putt, Mary E; Imray, Chris; Yow, Heng; Wilson, Mark H; Yodh, Arjun G; Grocott, Mike; Martin, Daniel S

2015-06-01

Alterations in cerebral blood flow (CBF) and cerebral oxygenation are implicated in altitude-associated diseases. We assessed the dynamic changes in CBF and peripheral and cerebral oxygenation engendered by ascent to altitude with partial acclimatization and hyperventilation using a combination of near-infrared spectroscopy, transcranial Doppler ultrasound, and diffuse correlation spectroscopy. Peripheral (Spo2) and cerebral (Scto2) oxygenation, end-tidal carbon dioxide (ETCO2), and cerebral hemodynamics were studied in 12 subjects using transcranial Doppler and diffuse correlation spectroscopy (DCS) at 75 m and then 2 days and 7 days after ascending to 4559 m above sea level. After obtaining baseline measurements, subjects hyperventilated to reduce baseline ETCO2 by 50%, and a further set of measurements were obtained. Cerebral oxygenation and peripheral oxygenation showed a divergent response, with cerebral oxygenation decreasing at day 2 and decreasing further at day 7 at altitude, whereas peripheral oxygenation decreased on day 2 before partially rebounding on day 7. Cerebral oxygenation decreased after hyperventilation at sea level (Scto2 from 68.8% to 63.5%; P<.001), increased after hyperventilation after 2 days at altitude (Scto2 from 65.6% to 69.9%; P=.001), and did not change after hyperventilation after 7 days at altitude (Scto2 from 62.2% to 63.3%; P=.35). An intensification of the normal cerebral hypocapnic vasoconstrictive response occurred after partial acclimatization in the setting of divergent peripheral and cerebral oxygenation. This may help explain why hyperventilation fails to improve cerebral oxygenation after partial acclimatization as it does after initial ascent. The use of DCS is feasible at altitude and provides a direct measure of CBF indices with high temporal resolution. Copyright © 2015 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Increased plasma fibrinopeptide A levels during attacks induced by hyperventilation in patients with coronary vasospastic angina.

PubMed

Oshima, S; Ogawa, H; Yasue, H; Okumura, K; Matsuyama, K; Miyagi, H

1989-07-01

Plasma fibrinopeptide A levels, beta-thromboglobulin levels and platelet factor 4 levels were estimated by enzyme-linked immunosorbent assay before and after hyperventilation in 12 patients with coronary vasospastic angina and in 12 control subjects matched for age and gender. In all 12 study patients, anginal attacks accompanied by electrocardiographic (ECG) changes (ST elevation in 11 patients and ST depression in 1 patient) were induced by hyperventilation. Coronary angiography was performed on 11 of the 12 patients, and coronary artery spasm with the same ECG changes was induced by intracoronary injection of acetylcholine in all 11. The plasma fibrinopeptide A levels increased significantly from 2.0 +/- 0.4 to 10.0 +/- 2.4 ng/ml during the attack (p less than 0.001) in the study patients, but remained unchanged before and after hyperventilation in the control subjects. The plasma levels of beta-thromboglobulin and platelet factor 4 remained unchanged after hyperventilation in both groups. Our data indicate that coronary artery spasm may induce thrombin generation and trigger thrombus formation in the coronary artery.

In vivo measurement of regional brain metabolic response to hyperventilation using magnetic resonance: proton echo planar spectroscopic imaging (PEPSI).

PubMed

Posse, S; Dager, S R; Richards, T L; Yuan, C; Ogg, R; Artru, A A; Müller-Gärtner, H W; Hayes, C

1997-06-01

A new rapid spectroscopic imaging technique with improved sensitivity and lipid suppression, referred to as Proton Echo Planar Spectroscopic Imaging (PEPSI), has been developed to measure the 2-dimensional distribution of brain lactate increases during hyperventilation on a conventional clinical scanner equipped with a head surface coil phased array. PEPSI images (nominal voxel size: 1.125 cm3) in five healthy subjects from an axial section approximately 20 mm inferior to the intercommissural line were obtained during an 8.5-min baseline period of normocapnia and during the final 8.5 min of a 10-min period of capnometry-controlled hyperventilation (end-tidal PCO2 of 20 mmHg). The lactate/N-acetyl aspartate signal increased significantly from baseline during hyperventilation for the insular cortex, temporal cortex, and occipital regions of both the right and left hemisphere, but not in the basal ganglia. Regional or hemispheric right-to-left differences were not found. The study extends previous work using single-voxel MR spectroscopy to dynamically study hyperventilation effects on brain metabolism.

Hyperventilation accelerates rise in arterial blood concentrations of sevoflurane in gynecologic patients.

PubMed

Lu, Chih-Cherng; Lin, Tso-Chou; Hsu, Che-Hao; Yu, Mu-Hsien; Ku, Chih-Hung; Chen, Ta-Liang; Chen, Ruei-Ming; Ho, Shung-Tai

2013-02-01

We investigated whether ventilation volumes affected arterial blood sevoflurane concentration (A (sev)) and its uptake into the body during general anesthesia. Thirty female patients undergoing elective gynecologic surgery were randomly allocated into three groups: hyperventilation, normal ventilation, and hypoventilation. Inspiratory (CI(sev)) and end-tidal ((sev)) sevoflurane concentrations were routinely measured by infrared analysis, and A (sev) were analyzed by gas chromatography for 40 min after intubation. Cardiac index and total peripheral vascular resistance were measured with a Finometer. During the first 10 min after sevoflurane administration, A (sev) in the hyperventilation group was the highest and differed significantly from those in the normal ventilation group, followed by those in the hypoventilation group. In addition, hyperventilation significantly increased the slope of A (sev) over time in the first 5 min, but there were no differences in slopes in the 5-10, 10-20, and 20-40 min periods, which indicates no difference in sevoflurane bodily uptake among the three groups after 5 min. Hyperventilation accelerated the rate of A (sev) increase immediately after sevoflurane administration, which was time dependent with respect to different alveolar ventilation levels.

Hyperventilation-induced nystagmus in a large series of vestibular patients.

PubMed

Califano, L; Melillo, M G; Vassallo, A; Mazzone, S

2011-02-01

The Hyperventilation Test is widely used in the "bed-side examination" of vestibular patients. It can either activate a latent nystagmus in central or peripheral vestibular diseases or it can interact with a spontaneous nystagmus, by reducing it or increasing it. Aims of this study were to determine the incidence, patterns and temporal characteristics of Hyperventilation-induced nystagmus in patients suffering from vestibular diseases, as well as its contribution to the differential diagnosis between vestibular neuritis and neuroma of the 8(th) cranial nerve, and its behaviour in some central vestibular diseases. The present study includes 1202 patients featuring, at vestibular examination, at least one sign of vestibular system disorders or patients diagnosed with a "Migraine-related vertigo" or "Chronic subjective dizziness". The overall incidence of Hyperventilation-induced nystagmus was 21.9%. It was detected more frequently in retrocochlear vestibular diseases rather than in end-organ vestibular diseases: 5.3% in Paroxysmal Positional Vertigo, 37.1% in Menière's disease, 37.6% in compensated vestibular neuritis, 77.2% in acute vestibular neuritis and 91.7% in neuroma of the 8(th) cranial nerve. In acute vestibular neuritis, three HVIN patterns were observed: Paretic pattern: temporary enhancement of the spontaneous nystagmus; Excitatory pattern: temporary inhibition of the spontaneous nystagmus; Strong excitatory pattern: temporary inversion of the spontaneous nystagmus. Excitatory patterns proved to be time-dependent in that they disappeared and were replaced by the paretic pattern over a period of maximum 18 days since the beginning of the disorder. In acoustic neuroma, Hyperventilation-induced nystagmus was frequently observed (91.7%), either in the form of an excitatory pattern (fast phases towards the affected site) or in the form of a paretic pattern (fast phases towards the healthy side). The direction of the nystagmus is only partially related to tumour size, whereas other mechanisms, such as demyelination or a break in nerve fibres, might have an important role in triggering the situation. Hyperventilation-induced nystagmus has frequently been detected in cases of demyelinating diseases and in cerebellar diseases: in multiple sclerosis, hyperventilation inhibits a central type of spontaneous nystagmus or evokes nystagmus in 75% of patients; in cerebellar diseases, hyperventilation evokes or enhances a central spontaneous nystagmus in 72.7% of patients. In conclusion the Hyperventilation Test can provide patterns of oculomotor responses that indicate a diagnostic investigation through cerebral magnetic resonance imaging enhanced by gadolinium, upon suspicion of neuroma of the 8(th) cranial nerve or of a central disease. In our opinion, however, Hyperventilation-induced nystagmus always needs to be viewed within the more general context of a complete examination of the vestibular and acoustic system.

Hyperventilation in Panic Disorder and Asthma: Empirical Evidence and Clinical Strategies

PubMed Central

Meuret, Alicia E.; Ritz, Thomas

2010-01-01

Sustained or spontaneous hyperventilation has been associated with a variety of physical symptoms and has been linked to a number of organic illnesses and mental disorders. Theories of panic disorder hold that hyperventilation either produces feared symptoms of hypocapnia or protects against feared suffocation symptoms of hypercapnia. Although the evidence for both theories is inconclusive, findings from observational, experimental, and therapeutic studies suggest an important role of low carbon dioxide (CO2) levels in this disorder. Similarly, hypocapnia and associated hyperpnia are linked to bronchoconstriction, symptom exacerbation, and lower quality of life in patients with asthma. Raising CO2 levels by means of therapeutic capnometry has proven beneficial effects in both disorders, and the reversing of hyperventilation has emerged as a potent mediator for reductions in panic symptom severity and treatment success. PMID:20685222

Changes in scalp and cortical blood flow during hyperventilation measured with diffusing-wave spectroscopy

NASA Astrophysics Data System (ADS)

Li, Jun; Ninck, Markus; Gisler, Thomas

2009-07-01

Changes in scalp and cortical blood flow induced by voluntary hyperventilation are investigated by near-infrared diffusing-wave spectroscopy. The temporal intensity autocorrelation function g(2) (τ) of multiply scattered light is recorded from the forehead of subjects during hyperventilation. Blood flow within the sampled tissue volume is estimated by the mean decay rate of g(2) (τ) . Data measured from six subjects show that the pattern of the hemodynamic response during 50 s hyperventilation is rather complicated: within the first 10 s, in three subjects an initial increase in blood flow is observed; from 10 s to 20 s, the mean blood flow is smaller than its baseline value for all six subjects; for the duration from 20 s to 30 s, the blood flow increases again. However, after 30 s the change is not consistent across subjects. Further study on one of these subjects by using two receivers probing the blood flow in the cortex and in the superficial layers simultaneously, reveals that during hyperventilation, the direction of change in blood flow within the scalp is opposite to the one in the brain. This helps to understand the complicated hemodynamic response observed in our measurements.

Onset of Hyperventilation during Incremental Exercise: A Brief Review.

ERIC Educational Resources Information Center

Powers, Scott K.; Beadle, Ralph E.

1985-01-01

This review discussed the various mechanisms that have been proposed to be causative of the hyperventilation that occurs during heavy exercise. The humoral hypothesis and nonhumoral hypothesis and secondary factors are reviewed. (MT)

Head-up tilt and hyperventilation produce similar changes in cerebral oxygenation and blood volume: an observational comparison study using frequency-domain near-infrared spectroscopy

PubMed Central

Mantulin, William W.; Alexander, Brenton S.; Cerussi, Albert E.; Tromberg, Bruce J.; Yu, Zhaoxia; Laning, Kathleen; Kain, Zeev N.; Cannesson, Maxime; Gelb, Adrian W.

2012-01-01

Purpose During anesthesia, maneuvers which cause the least disturbance of cerebral oxygenation with the greatest decrease in intracranial pressure would be most beneficial to patients with intracranial hypertension. Both head-up tilt (HUT) and hyperventilation are used to decrease brain bulk, and both may be associated with decreases in cerebral oxygenation. In this observational study, our null hypothesis was that the impact of HUT and hyperventilation on cerebral tissue oxygen saturation (SctO2) and cerebral blood volume (CBV) are comparable. Methods Surgical patients without neurological disease were anesthetized with propofol-remifentanil. Before the start of surgery, frequency-domain near-infrared spectroscopy was used to measure SctO2 and CBV at the supine position, at the 30° head-up and head-down positions, as well as during hypoventilation and hyperventilation. Results Thirty-three patients were studied. Both HUT and hyperventilation induced small decreases in SctO2 [3.5 (2.6)%; P <0.001 and 3.0 (1.8)%; P <0.001, respectively] and in CBV [0.05 (0.07) mL·100 g−1; P <0.001 and 0.06 (0.05) mL·100 g−1; P <0.001, respectively]. There were no differences between HUT to 30° and hyperventilation to an end-tidal carbon dioxide (ETCO2) of 25 mmHg (from 45 mmHg) in both SctO2 (P = 0.3) and CBV (P = 0.4). Discussion The small but statistically significant decreases in both SctO2 and CBV caused by HUT and hyperventilation are comparable. There was no correlation between the decreases in SctO2 and CBV and the decreases in blood pressure and cardiac output during head-up and head-down tilts. However, the decreases in both SctO2 and CBV correlate with the decreases in ETCO2 during ventilation adjustment. PMID:22234820

Head-up tilt and hyperventilation produce similar changes in cerebral oxygenation and blood volume: an observational comparison study using frequency-domain near-infrared spectroscopy.

PubMed

Meng, Lingzhong; Mantulin, William W; Alexander, Brenton S; Cerussi, Albert E; Tromberg, Bruce J; Yu, Zhaoxia; Laning, Kathleen; Kain, Zeev N; Cannesson, Maxime; Gelb, Adrian W

2012-04-01

During anesthesia, maneuvers which cause the least disturbance of cerebral oxygenation with the greatest decrease in intracranial pressure would be most beneficial to patients with intracranial hypertension. Both head-up tilt (HUT) and hyperventilation are used to decrease brain bulk, and both may be associated with decreases in cerebral oxygenation. In this observational study, our null hypothesis was that the impact of HUT and hyperventilation on cerebral tissue oxygen saturation (SctO2) and cerebral blood volume (CBV) are comparable. Surgical patients without neurological disease were anesthetized with propofol-remifentanil. Before the start of surgery, frequency-domain near-infrared spectroscopy was used to measure SctO2 and CBV at the supine position, at the 30° head-up and head-down positions, as well as during hypoventilation and hyperventilation. Thirty-three patients were studied. Both HUT and hyperventilation induced small decreases in SctO2 [3.5 (2.6)%; P < 0.001 and 3.0 (1.8)%; P < 0.001, respectively] and in CBV [0.05 (0.07) mL x 100 g(-1); P < 0.001 and 0.06 (0.05) mL x 100 g(-1); P < 0.001, respectively]. There were no differences between HUT to 30° and hyperventilation to an end-tidal carbon dioxide (ETCO2) of 25 mmHg (from 45 mmHg) in both SctO2 (P = 0.3) and CBV (P = 0.4). The small but statistically significant decreases in both SctO2 and CBV caused by HUT and hyperventilation are comparable. There was no correlation between the decreases in SctO2 and CBV and the decreases in blood pressure and cardiac output during head-up and head-down tilts. However, the decreases in both SctO2 and CBV correlate with the decreases in ETCO2 during ventilation adjustment.

[Assessment of influence of breath holding and hyperventilation on human postural stability with spectral analysis of stabilographic signal].

PubMed

Malakhov, M V; Makarenkova, E A; Mel'nikov, A A; Vikulov, A D

2014-01-01

The influence of breath holding and voluntary hyperventilation on the classic stabilometric parameters and the frequency characteristic of stabilographic signal were studied. We measured the stabilometric parameters on the force platform ("Ritm", Russia) on the healthy volunteers (n = 107) during quiet breath, voluntary hyperventilation (20 seconds) and maximal inspiratory breath holding (20 seconds). Respiratory frequency, respiratory amplitude and ventilation were estimated with strain gauge. We found that antero-posterior and medio-lateral sway amplitude and velocity as well as sway surface at breath-holding and at quiet breathing were the same, so breath holding didn't influence the postural stability. However the spectral parameters shifted to the high frequency range due to alteration of the respiratory muscles contractions during breath-holding versus quiet breath. Voluntary hyperventilation caused significant increase of all stabilographic indices that implied an impairment of postural stability, which was due to the increase of respiration frequency and amplitude. We also found that the spectral indices moved toward the high-frequency range with more pronounced degree of this shift versus breath holding. Besides, amplitudes of spectral peaks also increased. Perhaps such change of spectral indices was due to distortion of proprioceptive information because of increased excitability of nerve fibers during hyperventilation. Maximal inspiration breath holding causes strain of the postural control mechanisms that is reflected as elevation of postural sway frequency with no postural stability changes. Hyperventilation leads to the most prominent strain of balance function and decrease of steadiness that is manifested as increase of center of pressure oscillations amplitude and frequency.

Postural control and ventilatory drive during voluntary hyperventilation and carbon dioxide rebreathing.

PubMed

David, Pascal; Laval, David; Terrien, Jérémy; Petitjean, Michel

2012-01-01

The present study sought to establish links between hyperventilation and postural stability. Eight university students were asked to stand upright under two hyperventilation conditions applied randomly: (1) a metabolic hyperventilation induced by 5 min of hypercapnic-hyperoxic rebreathing (CO(2)-R); and, (2) a voluntary hyperventilation (VH) of 3 min imposed by a metronome set at 25 cycles per min. Recordings were obtained with eyes open, with the subjects standing on a force plate over 20-s periods. Ventilatory response, displacements in the centre of pressure in both the frontal and sagittal planes and fluctuations in the three planes of the ground reaction force were monitored in the time and frequency domains. Postural changes related to respiratory variations were quantified by coherence analysis. Myoelectric activities of the calf muscles were recorded using surface electromyography. Force plate measurements revealed a reduction in postural stability during both CO(2)-R and VH conditions, mainly in the sagittal plane. Coherence analysis provided evidence of a ventilatory origin in the vertical ground reaction force fluctuations during VH. Electromyographic analyses showed different leg muscles strategies, assuming the existence of links between the control of respiration and the control of posture. Our results suggest that the greater disturbing effects caused by voluntary hyperventilation on body balance are more compensated when respiration is under automatic control. These findings may have implications for understanding the organisation of postural and respiratory activities and suggest that stability of the body may be compromised in situations in which respiratory demand increases and requires voluntary control.

A Case of Neuro-Behcet's Disease Presenting with Central Neurogenic Hyperventilation.

PubMed

Alkhachroum, Ayham M; Saeed, Saba; Kaur, Jaspreet; Shams, Tanzila; DeGeorgia, Michael A

2016-03-11

Behcet's disease is a chronic inflammatory disorder usually characterized by the triad of oral ulcers, genital ulcers, and uveitis. Central to the pathogenesis of Behcet's disease is an autoimmune vasculitis. Neurological involvement, so called "Neuro-Behcet's disease", occurs in 10-20% of patients, usually from a meningoencephalitis or venous thrombosis. We report the case of a 46-year-old patient with Neuro-Behcet's disease who presented with central neurogenic hyperventilation as a result of brainstem involvement from venulitis. To the best of our knowledge, central neurogenic hyperventilation has not previously been described in a patient with Neuro-Behcet's disease.

Failure of perception of hypocapnia: physiological and clinical implications.

PubMed Central

King, J C; Rosen, S D; Nixon, P G

1990-01-01

Hyperventilation causes hypocapnia and respiratory alkalosis and thereby predisposes to coronary vasoconstriction and cardiac arrhythmia. Diagnostic methods for use between episodes have not been established. In this study of 100 patients and 25 control subjects the resting end-tidal PCO2 (Pet CO2) levels and the results of a forced hyperventilation test did not show a significant difference between the groups. However the patients hyperventilated more profoundly in response to emotional stimulation, and were less aware of inappropriate breathing and hypocapnia. It is suggested that these differences should be accommodated in cardiac rehabilitation. PMID:2125316

Hypercapnia shortens emergence time from inhaled anesthesia in pigs.

PubMed

Gopalakrishnan, Nishant A; Sakata, Derek J; Orr, Joseph A; McJames, Scott; Westenskow, Dwayne R

2007-04-01

Anesthetic clearance from the lungs and the circle rebreathing system can be maximized using hyperventilation and high fresh gas flows. However, the concomitant clearance of CO2 decreases PAco2, thereby decreasing cerebral blood flow and slowing the clearance of anesthetic from the brain. This study shows that in addition to hyperventilation, hypercapnia (CO2 infusion or rebreathing) is a significant factor in decreasing emergence time from inhaled anesthesia. We anesthetized seven pigs with 2 MACPIG of isoflurane and four with 2 MACPIG of sevoflurane. After 2 h, anesthesia was discontinued, and the animals were hyperventilated. The time to movement of multiple limbs was measured under hypocapnic (end-tidal CO2 = 22 mm Hg) and hypercapnic (end-tidal CO2 = 55 mm Hg) conditions. The time between turning off the vaporizer and to movement of multiple limbs was faster with hypercapnia during hyperventilation. Emergence time from isoflurane and sevoflurane anesthesia was shortened by an average of 65% with rebreathing or with the use of a CO2 controller (P < 0.05). Hypercapnia, along with hyperventilation, may be used clinically to decrease emergence time from inhaled anesthesia. These time savings might reduce drug costs. In addition, higher PAco2 during emergence may enhance respiratory drive and airway protection after tracheal extubation.

Prolonged post-hyperventilation apnea in two young adults with hyperventilation syndrome

PubMed Central

2013-01-01

Background The prognosis of hyperventilation syndrome (HVS) is generally good. However, it is important to proceed with care when treating HVS because cases of death following hyperventilation have been reported. This paper was done to demonstrate the clinical risk of post-hyperventilation apnea (PHA) in patients with HVS. Case presentation We treated two patients with HVS who suffered from PHA. The first, a 21-year-old woman, had a maximum duration of PHA of about 3.5 minutes and an oxygen saturation (SpO2) level of 60%. The second patient, a 22-year-old woman, had a maximum duration of PHA of about 3 minutes and an SpO2 level of 66%. Both patients had loss of consciousness and cyanosis. Because there is no widely accepted regimen for treating patients with prolonged PHA related to HVS, we administered artificial ventilation to both patients using a bag mask and both recovered without any after effects. Conclusion These cases show that some patients with HVS develop prolonged PHA or severe hypoxia, which has been shown to lead to death in some cases. Proper treatment must be given to patients with HVS who develop PHA to protect against this possibility. If prolonged PHA or severe hypoxemia arises, respiratory assistance using a bag mask must be done immediately. PMID:23594702

PubMed Central

CALIFANO, L.; MELILLO, M.G.; VASSALLO, A.; MAZZONE, S.

2011-01-01

SUMMARY The Hyperventilation Test is widely used in the "bed-side examination" of vestibular patients. It can either activate a latent nystagmus in central or peripheral vestibular diseases or it can interact with a spontaneous nystagmus, by reducing it or increasing it. Aims of this study were to determine the incidence, patterns and temporal characteristics of Hyperventilation-induced nystagmus in patients suffering from vestibular diseases, as well as its contribution to the differential diagnosis between vestibular neuritis and neuroma of the 8th cranial nerve, and its behaviour in some central vestibular diseases. The present study includes 1202 patients featuring, at vestibular examination, at least one sign of vestibular system disorders or patients diagnosed with a "Migraine-related vertigo" or "Chronic subjective dizziness". The overall incidence of Hyperventilation-induced nystagmus was 21.9%. It was detected more frequently in retrocochlear vestibular diseases rather than in end-organ vestibular diseases: 5.3% in Paroxysmal Positional Vertigo, 37.1% in Menière's disease, 37.6% in compensated vestibular neuritis, 77.2% in acute vestibular neuritis and 91.7% in neuroma of the 8th cranial nerve. In acute vestibular neuritis, three HVIN patterns were observed: Paretic pattern: temporary enhancement of the spontaneous nystagmus; Excitatory pattern: temporary inhibition of the spontaneous nystagmus; Strong excitatory pattern: temporary inversion of the spontaneous nystagmus. Excitatory patterns proved to be time-dependent in that they disappeared and were replaced by the paretic pattern over a period of maximum 18 days since the beginning of the disorder. In acoustic neuroma, Hyperventilation-induced nystagmus was frequently observed (91.7%), either in the form of an excitatory pattern (fast phases towards the affected site) or in the form of a paretic pattern (fast phases towards the healthy side). The direction of the nystagmus is only partially related to tumour size, whereas other mechanisms, such as demyelination or a break in nerve fibres, might have an important role in triggering the situation. Hyperventilation-induced nystagmus has frequently been detected in cases of demyelinating diseases and in cerebellar diseases: in multiple sclerosis, hyperventilation inhibits a central type of spontaneous nystagmus or evokes nystagmus in 75% of patients; in cerebellar diseases, hyperventilation evokes or enhances a central spontaneous nystagmus in 72.7% of patients. In conclusion the Hyperventilation Test can provide patterns of oculomotor responses that indicate a diagnostic investigation through cerebral magnetic resonance imaging enhanced by gadolinium, upon suspicion of neuroma of the 8th cranial nerve or of a central disease. In our opinion, however, Hyperventilation-induced nystagmus always needs to be viewed within the more general context of a complete examination of the vestibular and acoustic system. PMID:21808459

Impact of stepwise hyperventilation on cerebral tissue oxygen saturation in anesthetized patients: a mechanistic study.

PubMed

Alexander, B S; Gelb, A W; Mantulin, W W; Cerussi, A E; Tromberg, B J; Yu, Z; Lee, C; Meng, L

2013-05-01

While the decrease in blood carbon dioxide (CO2 ) secondary to hyperventilation is generally accepted to play a major role in the decrease of cerebral tissue oxygen saturation (SctO2 ), it remains unclear if the associated systemic hemodynamic changes are also accountable. Twenty-six patients (American Society of Anesthesiologists I-II) undergoing nonneurosurgical procedures were anesthetized with either propofol-remifentanil (n = 13) or sevoflurane (n = 13). During a stable intraoperative period, ventilation was adjusted stepwise from hypoventilation to hyperventilation to achieve a progressive change in end-tidal CO2 (ETCO2 ) from 55 to 25 mmHg. Minute ventilation, SctO2 , ETCO2 , mean arterial pressure (MAP), and cardiac output (CO) were recorded. Hyperventilation led to a SctO2 decrease from 78 ± 4% to 69 ± 5% (Δ = -9 ± 4%, P < 0.001) in the propofol-remifentanil group and from 81 ± 5% to 71 ± 7% (Δ = -10 ± 3%, P < 0.001) in the sevoflurane group. The decreases in SctO2 were not statistically different between these two groups (P = 0.5). SctO2 correlated significantly with ETCO2 in both groups (P < 0.001). SctO2 also correlated significantly with MAP (P < 0.001) and CO (P < 0.001) during propofol-remifentanil, but not sevoflurane (P = 0.4 and 0.5), anesthesia. The main mechanism responsible for the hyperventilation-induced decrease in SctO2 is hypocapnia during both propofol-remifentanil and sevoflurane anesthesia. Hyperventilation-associated increase in MAP and decrease in CO during propofol-remifentanil, but not sevoflurane, anesthesia may also contribute to the decrease in SctO2 but to a much smaller degree. © 2013 The Acta Anaesthesiologica Scandinavica Foundation.

Impact of stepwise hyperventilation on cerebral tissue oxygen saturation in anesthetized patients: a mechanistic study

PubMed Central

Alexander, B. S.; Gelb, A. W.; Mantulin, W. W.; Cerussi, A. E.; Tromberg, B. J.; Yu, Z.; Lee, C.; Meng, L.

2014-01-01

Background While the decrease in blood carbon dioxide (CO2) secondary to hyperventilation is generally accepted to play a major role in the decrease of cerebral tissue oxygen saturation (SctO2), it remains unclear if the associated systemic hemodynamic changes are also accountable. Methods Twenty-six patients (American Society of Anesthesiologists I–II) undergoing nonneurosurgical procedures were anesthetized with either propofol-remifentanil (n = 13) or sevoflurane (n = 13). During a stable intraoperative period, ventilation was adjusted stepwise from hypoventilation to hyper-ventilation to achieve a progressive change in end-tidal CO2 (ETCO2) from 55 to 25 mmHg. Minute ventilation, SctO2, ETCO2, mean arterial pressure (MAP), and cardiac output (CO) were recorded. Results Hyperventilation led to a SctO2 decrease from 78 ± 4% to 69 ± 5% (Δ = −9 ± 4%, P < 0.001) in the propofol-remifentanil group and from 81 ± 5% to 71 ± 7% (Δ = −10 ± 3%, P < 0.001) in the sevoflurane group. The decreases in SctO2 were not statistically different between these two groups (P = 0.5). SctO2 correlated significantly with ETCO2 in both groups (P < 0.001). SctO2 also correlated significantly with MAP (P < 0.001) and CO (P < 0.001) during propofol-remifentanil, but not sevoflurane (P = 0.4 and 0.5), anesthesia. Conclusion The main mechanism responsible for the hyperventilation-induced decrease in SctO2 is hypocapnia during both propofol-remifentanil and sevoflurane anesthesia. Hyperventilation-associated increase in MAP and decrease in CO during propofol-remifentanil, but not sevoflurane, anesthesia may also contribute to the decrease in SctO2 but to a much smaller degree. PMID:23278596

Physiological responses to psychological challenge under hypnosis in patients considered to have the hyperventilation syndrome: implications for diagnosis and therapy.

PubMed Central

Freeman, L J; Conway, A; Nixon, P G

1986-01-01

Thirty patients who were considered to have the hyperventilation syndrome on clinical grounds (history and observation) were referred for testing: 29 patients completed a forced hyperventilation provocation test, and 28 underwent hypnosis during which time a psychological challenge was introduced which was meaningful to each individual patient. In 19/27 of these patients the PetCO2 fell by an average of 18.2 mmHg and persisted spontaneously for more than three minutes. In 10 normal controls studied in a similar fashion there was an average fall of 5 mmHg. The difference in response between responders and controls/non-responders was highly significant (P less than 0.001). A review of the literature is presented for comparison. It is considered that a psychological challenge under hypnosis may have important implications for diagnosis and therapy in some patients considered to have the hyperventilation syndrome. Images Figure 2. Figure 3. Figure 4. Figure 5. PMID:3081708

Effects of Moderate Hyperventilation on Jugular Bulb Gases under Propofol or Isoflurane Anesthesia during Supratentorial Craniotomy.

PubMed

Meng, Lan; Li, Shu-Qin; Ji, Nan; Luo, Fang

2015-05-20

The optimal ventilated status under total intravenous or inhalation anesthesia in neurosurgical patients with a supratentorial tumor has not been ascertained. The purpose of this study was to intraoperatively compare the effects of moderate hyperventilation on the jugular bulb oxygen saturation (SjO 2 ), cerebral oxygen extraction ratio (O 2 ER), mean arterial blood pressure (MAP), and heart rate (HR) in patients with a supratentorial tumor under different anesthetic regimens. Twenty adult patients suffered from supratentorial tumors were randomly assigned to receive a propofol infusion followed by isoflurane anesthesia after a 30-min stabilization period or isoflurane followed by propofol. The patients were randomized to one of the following two treatment sequences: hyperventilation followed by normoventilation or normoventilation followed by hyperventilation during isoflurane or propofol anesthesia, respectively. The ventilation and end-tidal CO 2 tension were maintained at a constant level for 20 min. Radial arterial and jugular bulb catheters were inserted for the blood gas sampling. At the end of each study period, we measured the change in the arterial and jugular bulb blood gases. The mean value of the jugular bulb oxygen saturation (SjO 2 ) significantly decreased, and the oxygen extraction ratio (O 2 ER) significantly increased under isoflurane or propofol anesthesia during hyperventilation compared with those during normoventilation (SjO 2 : t = -2.728, P = 0.011 or t = -3.504, P = 0.001; O 2 ER: t = 2.484, P = 0.020 or t = 2.892, P = 0.009). The SjO 2 significantly decreased, and the O 2 ER significantly increased under propofol anesthesia compared with those values under isoflurane anesthesia during moderate hyperventilation (SjO 2 : t = -2.769, P = 0.012; O 2 ER: t = 2.719, P = 0.013). In the study, no significant changes in the SjO 2 and the O 2 ER were observed under propofol compared with those values under isoflurane during normoventilation. Our results suggest that the optimal ventilated status under propofol or isoflurane anesthesia in neurosurgical patients varies. Hyperventilation under propofol anesthesia should be cautiously performed in neurosurgery to maintain an improved balance between the cerebral oxygen supply and demand.

Tetany During Intravenous Conscious Sedation in Dentistry Resulting From Hyperventilation-Induced Hypocapnia.

PubMed

McCarthy, Caroline; Brady, Paul; O'Halloran, Ken D; McCreary, Christine

2016-01-01

Hyperventilation can be a manifestation of anxiety that involves abnormally fast breathing (tachypnea) and an elevated minute ventilation that exceeds metabolic demand. This report describes a case of hyperventilation-induced hypocapnia resulting in tetany in a 16-year-old girl undergoing orthodontic extractions under intravenous conscious sedation. Pulse oximetry is the gold standard respiratory-related index in conscious sedation. Although the parameter has great utility in determining oxygen desaturation, it provides no additional information on respiratory function, including, for example, respiratory rate. In this case, we found capnography to be a very useful aid to monitor respiration in this patient and also to treat the hypocapnia.

Psychosis, central hyperventilation and inappropriate secretion of antidiuretic hormone in systemic lupus erythematosus

PubMed Central

Decaux, G.; Unger, J.; Marneffe, C.

1981-01-01

A case of systemic lupus erythematosus with reversible psychosis and hyperventilation related to hyponatraemia secondary to a syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is presented. The SIADH was treated successfully by oral urea for more than 8 months. PMID:7339606

A second mechanism of increase of cerebellar hypermetria in humans

PubMed Central

Manto, Mario-Ubaldo; Bosse, Pierre

2003-01-01

So far, there is only one procedure known to increase hypermetria in cerebellar patients. Facing an increased inertia of the moving limb, patients presenting a lesion of the lateral cerebellum are able to increase appropriately the intensity of the agonist electromyographic (EMG) activity (the launching force), but are unable to adapt the intensity of the antagonist activity (the braking force). As a result, hypermetria is larger when the inertial load is artificially increased. Recent studies have demonstrated that hyperventilation increases hypermetria in patients presenting a spinocerebellar ataxia type 6 (SCA 6), a disorder associated with polyglutamine expansions in the α1A-voltage-dependent calcium channel. The mechanism of this increase of hypermetria has not been identified so far. In the present work, we combined kinematic, EMG and transcranial Doppler studies to understand the effects of hyperventilation on fast goal-directed movements in patients presenting a SCA 6. Both in the normal mechanical state and after increasing the inertial load of the moving hand, hyperventilation induced an increase of hypermetria. Hyperventilation increased the delay of the onset latency of the antagonist EMG activity and decreased the rate of rise of both the agonist and the antagonist EMG activities. Hyperventilation induced a marked decrease in cerebral blood flow velocities. The mechanism of this provocative test is original and is distinct from the mechanism of the load-induced increase of hypermetria. PMID:12588903

Hyperventilation accelerates the rise of arterial blood concentrations of desflurane in gynecologic patients.

PubMed

Lu, Chih-Cherng; Lin, Tso-Chou; Hsu, Che-Hao; Yu, Mu-Hsien; Chen, Ta-Liang; Chen, Ruei-Ming; Ku, Chih-Hung; Ho, Shung-Tai

2012-09-01

Under a constant inspired concentration, the uptake of a volatile anesthetic into the arterial blood should mainly be governed by alveolar ventilation, according to the assumption that the patient's cardiac output remains stable during anesthesia. We investigated whether ventilation volume affects the rate of desflurane uptake by examining arterial blood concentrations. Thirty female patients were randomly allocated into the following three groups: hyperventilation, normal ventilation and hypoventilation. Hemodynamic variables were measured using a Finometer, inspiratory and end-tidal concentrations of desflurane were measured by infrared analysis, and the desflurane concentration in the arterial blood (Ades) was analyzed by gas chromatography. During the first 10 minutes after the administration of desflurane, the Ades was highest in the hyperventilation group, and this value was significantly different from those obtained for the normal and hypoventilation groups. In addition, hyperventilation significantly increased the slope of Ades-over-time during the first 5 minutes compared with patients experiencing normal ventilation and hypoventilation, but there were no differences in these slopes during the periods from 5-10, 10-20 and 20-40 minutes after the administration of desflurane. This finding indicates that there were no differences in desflurane uptake between the three groups after the first 5 minutes within desflurane administration. Hyperventilation accelerated the rate of the rise in Ades following desflurane administration, which was time-dependent with respect to different alveolar ventilations levels.

Hyperventilation accelerates the rise of arterial blood concentrations of desflurane in gynecologic patients

PubMed Central

Lu, Chih-Cherng; Lin, Tso-Chou; Hsu, Che-Hao; Yu, Mu-Hsien; Chen, Ta-Liang; Chen, Ruei-Ming; Ku, Chih-Hung; Ho, Shung-Tai

2012-01-01

OBJECTIVES: Under a constant inspired concentration, the uptake of a volatile anesthetic into the arterial blood should mainly be governed by alveolar ventilation, according to the assumption that the patient's cardiac output remains stable during anesthesia. We investigated whether ventilation volume affects the rate of desflurane uptake by examining arterial blood concentrations. METHOD: Thirty female patients were randomly allocated into the following three groups: hyperventilation, normal ventilation and hypoventilation. Hemodynamic variables were measured using a Finometer, inspiratory and end-tidal concentrations of desflurane were measured by infrared analysis, and the desflurane concentration in the arterial blood (Ades) was analyzed by gas chromatography. RESULTS: During the first 10 minutes after the administration of desflurane, the Ades was highest in the hyperventilation group, and this value was significantly different from those obtained for the normal and hypoventilation groups. In addition, hyperventilation significantly increased the slope of Ades-over-time during the first 5 minutes compared with patients experiencing normal ventilation and hypoventilation, but there were no differences in these slopes during the periods from 5-10, 10-20 and 20-40 minutes after the administration of desflurane. This finding indicates that there were no differences in desflurane uptake between the three groups after the first 5 minutes within desflurane administration. CONCLUSIONS: Hyperventilation accelerated the rate of the rise in Ades following desflurane administration, which was time-dependent with respect to different alveolar ventilations levels. PMID:23018299

Delayed refractory hyperventilation following endoscopic third ventriculostomy in a 5-year-old boy.

PubMed

Merola, J; Liang, E; Hoskins, J; Balakrishnan, V; Gan, P

2016-09-01

We present the case of a 5-year-old boy who developed a delayed onset intractable hyperventilation following endoscopic third ventriculostomy. The proposed aetiology of this exceptionally rare phenomenon is discussed. To our knowledge, previous cases have only been reported in the adult population.

The Effects of Differing Oxygen Concentrations on Reaction Time Performance at Altitude

DTIC Science & Technology

2014-12-04

49, 943-946. Harding, R. M., Mills, F. J. (1983). Problems of altitude: Hypoxia and hyperventilation . British Medical Journal, 286, 1408-1410...K. P., Schippers, N., & Van den Bergh, O. (2000). Hyperventilation and attention: effects of hypocapnia on performance in a Stroop task. Biological

The hyperventilation-induced ischaemia model in human neuropharmacology: neurophysiological and psychometric studies of aniracetam and 3-OH aniracetam.

PubMed

Kraaier, V; van Huffelen, A C; Wieneke, G H

1989-01-01

Standardized hyperventilation in young subjects induces changes in the EEG, a decrease in the velocity of the cerebral blood flow and a decline in cognitive performance, which are comparable to those occurring in patients with cerebral ischaemia. The anti-ischaemic properties of aniracetam and 3-OH aniracetam were tested in this model. A single oral dose of 3-OH aniracetam 1500 mg appeared to have the most pronounced effect on hyperventilation-induced EEG changes and cognitive deterioration. The test drugs had no effect on the heart rate or blood flow velocity. The effects agree with those of other drugs classified as noötropics.

Tetany During Intravenous Conscious Sedation in Dentistry Resulting From Hyperventilation-Induced Hypocapnia

PubMed Central

McCarthy, Caroline; Brady, Paul; O'Halloran, Ken D.; McCreary, Christine

2016-01-01

Hyperventilation can be a manifestation of anxiety that involves abnormally fast breathing (tachypnea) and an elevated minute ventilation that exceeds metabolic demand. This report describes a case of hyperventilation-induced hypocapnia resulting in tetany in a 16-year-old girl undergoing orthodontic extractions under intravenous conscious sedation. Pulse oximetry is the gold standard respiratory-related index in conscious sedation. Although the parameter has great utility in determining oxygen desaturation, it provides no additional information on respiratory function, including, for example, respiratory rate. In this case, we found capnography to be a very useful aid to monitor respiration in this patient and also to treat the hypocapnia. PMID:26866408

Is chronic fatigue syndrome synonymous with effort syndrome?

PubMed Central

Rosen, S D; King, J C; Wilkinson, J B; Nixon, P G

1990-01-01

Chronic fatigue syndrome (CFS), including myalgic encephalomyelitis (ME) and postviral syndrome (PVS), is a term used today to describe a condition of incapacity for making and sustaining effort, associated with a wide range of symptoms. None of the reviews of CFS has provided a proper consideration of the effort syndrome caused by chronic habitual hyperventilation. In 100 consecutive patients, whose CFS had been attributed to ME or PVS, the time course of their illness and the respiratory psychophysiological studies were characteristic of chronic habitual hyperventilation in 93. It is suggested that the labels 'CFS', 'ME' or 'PVS' should be withheld until chronic habitual hyperventilation - for which conventional rehabilitation is available - has been definitively excluded. PMID:2125315

Panic Reactivity to Voluntary Hyperventilation Challenge Predicts Distress Tolerance to Bodily Sensations among Daily Cigarette Smokers

PubMed Central

Marshall, Erin C.; Zvolensky, Michael J.; Vujanovic, Anka A.; Gregor, Kristin; Gibson, Laura E.; Leyro, Teresa M.

2008-01-01

The present investigation examined the extent to which panic reactivity to bodily sensations is related to distress tolerance (DT) among daily smokers. It was hypothesized that panic reactivity to an initial voluntary hyperventilation (i.e., whether participants met criteria for a DSM-IV panic attack; PA) would predict the relative degree of task persistence on a second hyperventilation trial (DT) above and beyond the variance accounted for by anxiety sensitivity (AS), negative affectivity (NA), cigarette smoking rate, and self-reported discomfort intolerance (DI). Participants were 95 daily smokers (58% women; Mage = 29.0, SD = 12.2) who completed a battery of questionnaires and two voluntary hyperventilation procedures. Results indicated PA status significantly predicted DT, above and beyond the theoretically relevant covariates of AS, NA, cigarettes per day, and DI (p < .05). Such a result is consistent with theoretical models and empirical findings on emotional reactivity that suggest panic responsivity to internal cues may represent a key explanatory construct in terms of level of DT to interoceptive stimuli. PMID:18729685

Physiology and pathophysiology of respiratory arrest by cyanide poisoning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klimmek, R.

1993-05-13

Respiratory arrest, preceded by hyperventilation, is the primary cause of death in acute cyanide poisoning. Hyperventilation followed by apnea is also observed without intoxication. Hyperventilation and apnea in untoxicated subjects and animals are analyzed for the underlying physiological and biochemical changes and compared with those found during cyanide poisoning. The study reveals that the respiratory autoregulation appears to be the same under both conditions. Respiratory arrest is controlled by cerebral PCO2 and can occur without hypoxia or inhibition of cytochrome oxidase. It is postulated that respiratory arrest is a 'desperate act' thrust on the respiratory neurons by a critical exhaustionmore » of their energy store (ATP) due to the rapid firing in the period of hyperventilation. The point of no return may be reached when anoxia and/or partial inhibition of cytochrome oxidase prevent the neurons from replenishing the ATP store. The formation of Fe3+ cyanide complexes. exemplified by the metHb producer DMAP, appears to give the best results with regard to the restoration of spontaneous respiration. The study of respiratory autoregulation may also be helpful in developing and understanding other therapeutic approaches.« less

Hyperventilation in anticipatory music performance anxiety.

PubMed

Studer, Regina Katharina; Danuser, Brigitta; Hildebrandt, Horst; Arial, Marc; Wild, Pascal; Gomez, Patrick

2012-09-01

Self-report studies have shown an association between music performance anxiety (MPA) and hyperventilation complaints. However, hyperventilation was never assessed physiologically in MPA. This study investigated the self-reported affective experience, self-reported physiological symptoms, and cardiorespiratory variables including partial pressure of end-tidal CO(2) (Petco(2)), which is an indicator for hyperventilation, in 67 music students before a private and a public performance. The response coherence between these response domains was also investigated. From the private to the public session, the intensity of all self-report variables increased (all p values < .001). As predicted, the higher the musician's usual MPA level, the larger were these increases (p values < .10). With the exception of Petco(2), the main cardiorespiratory variables also increased from the private to the public session (p values < .05). These increases were not modulated by the usual MPA level (p values > .10). Petco(2) showed a unique response pattern reflected by an MPA-by-session interaction (p < .01): it increased from the private to the public session for musicians with low MPA levels and decreased for musicians with high MPA levels. Self-reported physiological symptoms were related to the self-reported affective experience (p values < .05) rather than to physiological measures (p values > .17). These findings show for the first time how respiration is stimulated before a public performance in music students with different MPA levels. The hypothesis of a hyperventilation tendency in high-performance-anxious musicians is supported. The response coherence between physiological symptoms and physiological activation is weak.

Electroconvulsive therapy can benefit from controlled hyperventilation using a laryngeal mask.

PubMed

Haeck, Martina; Gillmann, Benjamin; Janouschek, Hildegard; Grözinger, Michael

2011-11-01

Hypocapnia through hyperventilation is a well-known procedure in electroconvulsive therapy (ECT) to enhance seizure activity. However, it has mostly been applied in an uncontrolled manner. Originally intended for a better management of the supraglottic airway, laryngeal masks are more suited to monitor levels of CO(2) during hyperventilation than face masks and thereby provide for the possibility of controlled hyperventilation (CHV). The impact of CHV was retrospectively studied in 114 consecutive patients; 65 of them had received ECT with CHV and 49 had received ECT with uncontrolled hyperventilation (UHV) directly prior to the time period when the laryneal mask was introduced to the ECT treatment procedure. The CO(2) level in the CHV group was aimed at 30 mmHg or below. CHV considerably enhanced the seizure activity leading to changes in clinically determined parameters of the treatment course: the necessity for increasing the electric charge, for re-stimulations (trend) and for bilateral stimulations was lower in the CHV group as compared to the UHV group. The improvement in the Global Assessment of Functioning Scores was not different in both groups. CHV was associated with a higher amount of prolonged seizures, with a reduced number of delirious symptoms after treatments and an attenuating effect on heart rate. Concluding, CHV can help to maintain the applied electric charge low without worsening the clinical outcome. Therefore, it is a helpful technical improvement. However, it should be used carefully with regard to prolonged seizures.

Dynamic cerebral autoregulation measured with coherent hemodynamics spectroscopy (CHS)

NASA Astrophysics Data System (ADS)

Kainerstorfer, Jana M.; Sassaroli, Angelo; Tgavalekos, Kristen T.; Fantini, Sergio

2015-03-01

Coherent Hemodynamics Spectroscopy (CHS) is a novel technique for non-invasive measurements of local microcirculation quantities such as the capillary blood transit times and dynamic autoregulation. The basis of CHS is to measure, for instance with near-infrared spectroscopy (NIRS), peripheral coherent hemodynamic changes that are induced by controlled perturbations in the systemic mean arterial pressure (MAP). In this study, the MAP perturbation was induced by the fast release of two pneumatic cuffs placed around the subject's thighs after they were kept inflated (at 200 mmHg) for two minutes. The resulting transient changes in cerebral oxy- (O) and deoxy- (D) hemoglobin concentrations measured with NIRS on the prefrontal cortex are then described by a novel hemodynamic model, from which quantifiable parameters such as the capillary blood transit time and a cutoff frequency for cerebral autoregulation are obtained. We present results on eleven healthy volunteers in a protocol involving measurements during normal breathing and during hyperventilation, which is known to cause a hypocapnia-induced increase in cerebral autoregulation. The measured capillary transit time was unaffected by hyperventilation (normal breathing: 1.1±0.1 s; hyperventilation: 1.1±0.1 s), whereas the cutoff frequency of autoregulation, which increases for higher autoregulation efficiency, was indeed found to be significantly greater during hyperventilation (normal breathing: 0.017±0.002 Hz; hyperventilation: 0.034±0.005 Hz). These results provide a validation of local cerebral autoregulation measurements with the new technique of CHS.

3D Late Gadolinium Enhancement in a Single Prolonged Breath-hold using Supplemental Oxygenation and Hyperventilation

PubMed Central

Roujol, Sébastien; Basha, Tamer A.; Akçakaya, Mehmet; Foppa, Murilo; Chan, Raymond H.; Kissinger, Kraig V.; Goddu, Beth; Berg, Sophie; Manning, Warren J.; Nezafat, Reza

2013-01-01

Purpose: To evaluate the feasibility of 3D single breath-hold late gadolinium enhancement (LGE) of the left ventricle (LV) using supplemental oxygen and hyperventilation and compressed-sensing acceleration. Methods: Breath-hold metrics (breath-hold duration, diaphragmatic/LV position drift, and maximum variation of RR interval) without and with supplemental oxygen and hyperventilation were assessed in healthy adult subjects using a real time single shot acquisition. Ten healthy subjects and 13 patients then underwent assessment of the proposed 3D breath-hold LGE acquisition (FOV=320×320×100 mm3, resolution=1.6×1.6×5.0 mm3, acceleration rate of 4) and a free breathing acquisition with right hemidiaphragm navigator (NAV) respiratory gating. Semi-quantitative grading of overall image quality, motion artifact, myocardial nulling, and diagnostic value was performed by consensus of two blinded observers. Results: Supplemental oxygenation and hyperventilation increased the breath-hold duration (35±11 s to 58±21 s, p<0.0125) without significant impact on diaphragmatic/LV position drift or maximum variation of RR interval (both p>0.01). LGE images were of similar quality when compared to free breathing acquisitions but with reduced total scan time (85±22 s to 35±6 s, p<0.001). Conclusions: Supplemental oxygenation and hyperventilation allow for prolonged breath-holding and enable single breath-hold 3D accelerated LGE with similar image quality as free breathing with NAV. PMID:24186772

Effects of short-term mechanical hyperventilation on cerebral blood flow and dynamic cerebral autoregulation in critically ill patients with sepsis.

PubMed

Berg, Ronan M G; Plovsing, Ronni R

2016-01-01

In sepsis, higher PaCO2 levels are associated with impaired dynamic cerebral autoregulation (dCA), which may expose the brain to hypo- and hyperperfusion during acute fluctuations in blood pressure. We hypothesised that short-term mechanical hyperventilation would dCA in critically ill patients with sepsis. Seven mechanically ventilated septic patients were included. We assessed dCA before and after 30 min of mechanical hyperventilation. Transfer function analysis of spontaneous oscillations in transcranial Doppler-based middle cerebral artery blood flow velocity (MCAv) and invasive mean arterial blood pressure was used to assess dCA. Mechanical enhance hyperventilation reduced the median PaCO2 from 5.3 (IQR, 5.0-6.5) to 4.7 (IQR, 4.2-5.1) kPa (p < 0.05). This was associated with a reduction in the median MCAv from 57 (IQR, 33-68) to 32 (IQR, 21-40) cm sec(-1) (p < 0.05). Apart from a small increase in gain in the low frequency range (2.32 [IQR 1.80-2.41] vs. 2.59 (2.40-4.64) cm mmHg(-1) sec(-1); p < 0.05), this was not associated with any enhancement in dCA. In conclusion, cerebral CO2 vasoreactivity was found to be preserved in septic patients; nevertheless, and in contrast to our working hypothesis, short-term mechanical hyperventilation did not enhance dCA.

Diagnostic yield of five minutes compared to three minutes hyperventilation during electroencephalography.

PubMed

Craciun, Laura; Varga, Edina Timea; Mindruta, Ioana; Meritam, Pirgit; Horváth, Zoltán; Terney, Daniella; Gardella, Elena; Alving, Jørgen; Vécsei, László; Beniczky, Sándor

2015-08-01

To investigate whether hyperventilation (HV) for 5min increases the diagnostic yield of electroencephalography (EEG) compared to 3min HV. data were evaluated from 1084 consecutive patients, from three European centres, referred to EEG on suspicion of epilepsy. Seizures and interictal EEG abnormalities precipitated during the first 3min and during the last 2min of the HV period (totally 5min) were determined. Eight hundred seventy-seven patients (81%) completed 5min HV. Seizures were precipitated during the first 3min of HV in 21 patients, and during the last 2min in four more patients. Interictal EEG abnormalities were precipitated in the first 3min of HV in 16 patients, and during the last 2min in 7 more patients. Psychogenic nonepileptic seizures occurred in eight patients during the first 3min of HV and in two more patients during the last 2min. No adverse events occurred during the last 2min of HV, but eight patients (1%) stopped HV during the last 2min because they were not able to hyperventilate further. 16% of seizures and 30% of interictal EEG abnormalities triggered by HV occurred during the last 2min of HV, suggesting the clinical usefulness of prolonged hyperventilation for 5min. The vast majority of patients (99%) who are able to hyperventilate for 3min can complete 5min HV, without additional adverse events. Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

Effect of airway acidosis and alkalosis on airway vascular smooth muscle responsiveness to albuterol.

PubMed

Cancado, Jose E; Mendes, Eliana S; Arana, Johana; Horvath, Gabor; Monzon, Maria E; Salathe, Matthias; Wanner, Adam

2015-04-02

In vitro and animal experiments have shown that the transport and signaling of β2-adrenergic agonists are pH-sensitive. Inhaled albuterol, a hydrophilic β2-adrenergic agonist, is widely used for the treatment of obstructive airway diseases. Acute exacerbations of obstructive airway diseases can be associated with changes in ventilation leading to either respiratory acidosis or alkalosis thereby affecting albuterol responsiveness in the airway. The purpose of this study was to determine if airway pH has an effect on albuterol-induced vasodilation in the airway. Ten healthy volunteers performed the following respiratory maneuvers: quiet breathing, hypocapnic hyperventilation, hypercapnic hyperventilation, and eucapnic hyperventilation (to dissociate the effect of pH from the effect of ventilation). During these breathing maneuvers, exhaled breath condensate (EBC) pH and airway blood flow response to inhaled albuterol (ΔQ̇aw) were assessed. Mean ± SE EBC pH (units) and ΔQ̇aw (μl.min(-1).mL(-1)) were 6.4 ± 0.1 and 16.8 ± 1.9 during quiet breathing, 6.3 ± 0.1 and 14.5 ± 2.4 during eucapnic hyperventilation, 6.6 ± 0.2 and -0.2 ± 1.8 during hypocapnic hyperventilation (p = 0.02 and <0.01 vs. quiet breathing), and 5.9 ± 0.1 and 2.0 ± 1.5 during hypercapnic hyperventilation (p = 0.02 and <0.02 vs quiet breathing). Albuterol responsiveness in the airway as assessed by ΔQ̇aw is pH sensitive. The breathing maneuver associated with decreased and increased EBC pH both resulted in a decreased responsiveness independent of the level of ventilation. These findings suggest an attenuated response to hydrophilic β2-adrenergic agonists during airway disease exacerbations associated with changes in pH. Registered at clinicaltrials.gov: NCT01216748 .

Effects of Moderate Hyperventilation on Jugular Bulb Gases under Propofol or Isoflurane Anesthesia during Supratentorial Craniotomy

PubMed Central

Meng, Lan; Li, Shu-Qin; Ji, Nan; Luo, Fang

2015-01-01

Background: The optimal ventilated status under total intravenous or inhalation anesthesia in neurosurgical patients with a supratentorial tumor has not been ascertained. The purpose of this study was to intraoperatively compare the effects of moderate hyperventilation on the jugular bulb oxygen saturation (SjO2), cerebral oxygen extraction ratio (O2ER), mean arterial blood pressure (MAP), and heart rate (HR) in patients with a supratentorial tumor under different anesthetic regimens. Methods: Twenty adult patients suffered from supratentorial tumors were randomly assigned to receive a propofol infusion followed by isoflurane anesthesia after a 30-min stabilization period or isoflurane followed by propofol. The patients were randomized to one of the following two treatment sequences: hyperventilation followed by normoventilation or normoventilation followed by hyperventilation during isoflurane or propofol anesthesia, respectively. The ventilation and end-tidal CO2 tension were maintained at a constant level for 20 min. Radial arterial and jugular bulb catheters were inserted for the blood gas sampling. At the end of each study period, we measured the change in the arterial and jugular bulb blood gases. Results: The mean value of the jugular bulb oxygen saturation (SjO2) significantly decreased, and the oxygen extraction ratio (O2ER) significantly increased under isoflurane or propofol anesthesia during hyperventilation compared with those during normoventilation (SjO2: t = −2.728, P = 0.011 or t = −3.504, P = 0.001; O2ER: t = 2.484, P = 0.020 or t = 2.892, P = 0.009). The SjO2 significantly decreased, and the O2ER significantly increased under propofol anesthesia compared with those values under isoflurane anesthesia during moderate hyperventilation (SjO2: t = −2.769, P = 0.012; O2ER: t = 2.719, P = 0.013). In the study, no significant changes in the SjO2 and the O2ER were observed under propofol compared with those values under isoflurane during normoventilation. Conclusions: Our results suggest that the optimal ventilated status under propofol or isoflurane anesthesia in neurosurgical patients varies. Hyperventilation under propofol anesthesia should be cautiously performed in neurosurgery to maintain an improved balance between the cerebral oxygen supply and demand. PMID:25963351

A case of Pitt-Hopkins syndrome with absence of hyperventilation.

PubMed

Inati, Adlette; Abbas, Hussein A; Korjian, Serge; Daaboul, Yazan; Harajeily, Mohamad; Saab, Raya

2013-12-01

Pitt-Hopkins syndrome is characterized by mental retardation, hyperventilation, and dysmorphic features due to TCF4 mutations. We report a case of Pitt-Hopkins syndrome in a 2½-year-old boy presenting with psychomotor retardation, recurrent respiratory tract infections, and dysmorphic features with absence of hyperventilation or other breathing abnormalities. Comparative genomic hybridization and quantitative real-time polymerase chain reaction were used to confirm TCF4 haploinsufficiency. Pitt-Hopkins syndrome is a rare debilitating disease that should be in the differential diagnosis of other neurodevelopmental disorders characterized by mental retardation and hypotonicity despite the absence of hyperapnea and seizures. Quantitative real-time polymerase chain reaction is another method to identify TCF4 and to confirm Pitt-Hopkins syndrome diagnosis.

Imaging the Effects of Oxygen Saturation Changes in Voluntary Apnea and Hyperventilation on Susceptibility-Weighted Imaging

PubMed Central

Chang, K.; Barnes, S.; Haacke, E.M.; Grossman, R.I.; Ge, Y.

2014-01-01

BACKGROUND AND PURPOSE Cerebrovascular oxygenation changes during respiratory challenges have clinically important implications for brain function, including cerebral autoregulation and the rate of brain metabolism. SWI is sensitive to venous oxygenation level by exploitation of the magnetic susceptibility of deoxygenated blood. We assessed cerebral venous blood oxygenation changes during simple voluntary breath-holding (apnea) and hyperventilation by use of SWI at 3T. MATERIALS AND METHODS We performed SWI scans (3T; acquisition time of 1 minute, 28 seconds; centered on the anterior commissure and the posterior commissure) on 10 healthy male volunteers during baseline breathing as well as during simple voluntary hyperventilation and apnea challenges. The hyperventilation and apnea tasks were separated by a 5-minute resting period. SWI venograms were generated, and the signal changes on SWI before and after the respiratory stress tasks were compared by means of a paired Student t test. RESULTS Changes in venous vasculature visibility caused by the respiratory challenges were directly visualized on the SWI venograms. The venogram segmentation results showed that voluntary apnea decreased the mean venous blood voxel number by 1.6% (P<.0001), and hyperventilation increased the mean venous blood voxel number by 2.7% (P<.0001). These results can be explained by blood CO2 changes secondary to the respiratory challenges, which can alter cerebrovascular tone and cerebral blood flow and ultimately affect venous oxygen levels. CONCLUSIONS These results highlight the sensitivity of SWI to simple and noninvasive respiratory challenges and its potential utility in assessing cerebral hemodynamics and vasomotor responses. PMID:24371029

Moderate hyperventilation during intravenous anesthesia increases net cerebral lactate efflux.

PubMed

Grüne, Frank; Kazmaier, Stephan; Sonntag, Hans; Stolker, Robert Jan; Weyland, Andreas

2014-02-01

Hyperventilation is known to decrease cerebral blood flow (CBF) and to impair cerebral metabolism, but the threshold in patients undergoing intravenous anesthesia is unknown. The authors hypothesized that reduced CBF associated with moderate hyperventilation might impair cerebral aerobic metabolism in patients undergoing intravenous anesthesia. Thirty male patients scheduled for coronary surgery were included in a prospective, controlled crossover trial. Measurements were performed under fentanyl-midazolam anesthesia in a randomized sequence aiming at partial pressures of carbon dioxide of 30 and 50 mmHg. Endpoints were CBF, blood flow velocity in the middle cerebral artery, and cerebral metabolic rates for oxygen, glucose, and lactate. Global CBF was measured using a modified Kety-Schmidt technique with argon as inert gas tracer. CBF velocity of the middle cerebral artery was recorded by transcranial Doppler sonography. Data were presented as mean (SD). Two-sided paired t tests and one-way ANOVA for repeated measures were used for statistical analysis. Moderate hyperventilation significantly decreased CBF by 60%, blood flow velocity by 41%, cerebral oxygen delivery by 58%, and partial pressure of oxygen of the jugular venous bulb by 45%. Cerebral metabolic rates for oxygen and glucose remained unchanged; however, net cerebral lactate efflux significantly increased from -0.38 (2.18) to -2.41(2.43) µmol min 100 g. Moderate hyperventilation, when compared with moderate hypoventilation, in patients with cardiovascular disease undergoing intravenous anesthesia increased net cerebral lactate efflux and markedly reduced CBF and partial pressure of oxygen of the jugular venous bulb, suggesting partial impairment of cerebral aerobic metabolism at clinically relevant levels of hypocapnia.

3D late gadolinium enhancement in a single prolonged breath-hold using supplemental oxygenation and hyperventilation.

PubMed

Roujol, Sébastien; Basha, Tamer A; Akçakaya, Mehmet; Foppa, Murilo; Chan, Raymond H; Kissinger, Kraig V; Goddu, Beth; Berg, Sophie; Manning, Warren J; Nezafat, Reza

2014-09-01

To evaluate the feasibility of three-dimensional (3D) single breath-hold late gadolinium enhancement (LGE) of the left ventricle (LV) using supplemental oxygen and hyperventilation and compressed-sensing acceleration. Breath-hold metrics [breath-hold duration, diaphragmatic/LV position drift, and maximum variation of R wave to R wave (RR) interval] without and with supplemental oxygen and hyperventilation were assessed in healthy adult subjects using a real-time single shot acquisition. Ten healthy subjects and 13 patients then underwent assessment of the proposed 3D breath-hold LGE acquisition (field of view = 320 × 320 × 100 mm(3) , resolution = 1.6 × 1.6 × 5.0 mm(3) , acceleration rate of 4) and a free-breathing acquisition with right hemidiaphragm navigator (NAV) respiratory gating. Semiquantitative grading of overall image quality, motion artifact, myocardial nulling, and diagnostic value was performed by consensus of two blinded observers. Supplemental oxygenation and hyperventilation increased the breath-hold duration (35 ± 11 s to 58 ± 21 s; P < 0.0125) without significant impact on diaphragmatic/LV position drift or maximum variation of RR interval (both P > 0.01). LGE images were of similar quality when compared with free-breathing acquisitions, but with reduced total scan time (85 ± 22 s to 35 ± 6 s; P < 0.001). Supplemental oxygenation and hyperventilation allow for prolonged breath-holding and enable single breath-hold 3D accelerated LGE with similar image quality as free breathing with NAV. Copyright © 2013 Wiley Periodicals, Inc.

Imaging the effects of oxygen saturation changes in voluntary apnea and hyperventilation on susceptibility-weighted imaging.

PubMed

Chang, K; Barnes, S; Haacke, E M; Grossman, R I; Ge, Y

2014-06-01

Cerebrovascular oxygenation changes during respiratory challenges have clinically important implications for brain function, including cerebral autoregulation and the rate of brain metabolism. SWI is sensitive to venous oxygenation level by exploitation of the magnetic susceptibility of deoxygenated blood. We assessed cerebral venous blood oxygenation changes during simple voluntary breath-holding (apnea) and hyperventilation by use of SWI at 3T. We performed SWI scans (3T; acquisition time of 1 minute, 28 seconds; centered on the anterior commissure and the posterior commissure) on 10 healthy male volunteers during baseline breathing as well as during simple voluntary hyperventilation and apnea challenges. The hyperventilation and apnea tasks were separated by a 5-minute resting period. SWI venograms were generated, and the signal changes on SWI before and after the respiratory stress tasks were compared by means of a paired Student t test. Changes in venous vasculature visibility caused by the respiratory challenges were directly visualized on the SWI venograms. The venogram segmentation results showed that voluntary apnea decreased the mean venous blood voxel number by 1.6% (P < .0001), and hyperventilation increased the mean venous blood voxel number by 2.7% (P < .0001). These results can be explained by blood CO2 changes secondary to the respiratory challenges, which can alter cerebrovascular tone and cerebral blood flow and ultimately affect venous oxygen levels. These results highlight the sensitivity of SWI to simple and noninvasive respiratory challenges and its potential utility in assessing cerebral hemodynamics and vasomotor responses. © 2014 by American Journal of Neuroradiology.

Hyperventilation and blood acid-base balance in hypercapnia exposed red drum (Sciaenops ocellatus).

PubMed

Ern, Rasmus; Esbaugh, Andrew J

2016-05-01

Hyperventilation is a common response in fish exposed to elevated water CO2. It is believed to lessen the respiratory acidosis associated with hypercapnia by lowering arterial PCO2, but the contribution of hyperventilation to blood acid-base compensation has yet to be quantified. Hyperventilation may also increase the flux of irons across the gill epithelium and the cost of osmoregulation, owing to the osmo-respiratory compromise. Therefore, hypercapnia exposed fish may increase standard metabolic rate (SMR) leaving less energy for physiological functions such as foraging, migration, growth and reproduction. Here we show that gill ventilation, blood PCO2 and total blood [CO2] increased in red drum (Sciaenops ocellatus) exposed to 1000 and 5000 µatm water CO2, and that blood PCO2 and total blood [CO2] decrease in fish during hypoxia induced hyperventilation. Based on these results we estimate the ventilatory contributions to total acid-base compensation in 1000 and 5000 µatm water CO2. We find that S. ocellatus only utilize a portion of its ventilatory capacity to reduce the acid-base disturbance in 1000 µatm water CO2. SMR was unaffected by both salinity and hypercapnia exposure indicating that the cost of osmoregulation is small relative to SMR, and that the lack of increased ventilation in 1000 µatm water CO2 despite the capacity to do so is not due to an energetic tradeoff between acid-base balance and osmoregulation. Therefore, while ocean acidification may impact ventilatory parameters, there will be little impact on the overall energy budget of S. ocellatus.

Outcome of Children with Hyperventilation-Induced High-Amplitude Rhythmic Slow Activity with Altered Awareness

ERIC Educational Resources Information Center

Barker, Alexander; Ng, Joanne; Rittey, Christopher D. C.; Kandler, Rosalind H.; Mordekar, Santosh R.

2012-01-01

Hyperventilation-induced high-amplitude rhythmic slow activity with altered awareness (HIHARS) is increasingly being identified in children and is thought to be an age-related non-epileptic electrographic phenomenon. We retrospectively investigated the clinical outcome in 15 children (six males, nine females) with HIHARS (mean age 7y, SD 1y 11mo;…

Pubertal Status and Emotional Reactivity to a Voluntary Hyperventilation Challenge Predicting Panic Symptoms and Somatic Complaints

ERIC Educational Resources Information Center

Leen-Feldner, Ellen W.; Reardon, Laura E.; Zvolensky, Michael J.

2007-01-01

The main and interactive effects of pubertal status and emotional reactivity to bodily sensations elicited by a voluntary hyperventilation challenge were examined in relation to panic symptoms and self- and parent-reported somatic complaints among 123 (56 females) adolescents between the ages of 12 and 17 years (M[age] = 15.05; SD = 1.50). As…

Infrared imaging based hyperventilation monitoring through respiration rate estimation

NASA Astrophysics Data System (ADS)

Basu, Anushree; Routray, Aurobinda; Mukherjee, Rashmi; Shit, Suprosanna

2016-07-01

A change in the skin temperature is used as an indicator of physical illness which can be detected through infrared thermography. Thermograms or thermal images can be used as an effective diagnostic tool for monitoring and diagnosis of various diseases. This paper describes an infrared thermography based approach for detecting hyperventilation caused due to stress and anxiety in human beings by computing their respiration rates. The work employs computer vision techniques for tracking the region of interest from thermal video to compute the breath rate. Experiments have been performed on 30 subjects. Corner feature extraction using Minimum Eigenvalue (Shi-Tomasi) algorithm and registration using Kanade Lucas-Tomasi algorithm has been used here. Thermal signature around the extracted region is detected and subsequently filtered through a band pass filter to compute the respiration profile of an individual. If the respiration profile shows unusual pattern and exceeds the threshold we conclude that the person is stressed and tending to hyperventilate. Results obtained are compared with standard contact based methods which have shown significant correlations. It is envisaged that the thermal image based approach not only will help in detecting hyperventilation but can assist in regular stress monitoring as it is non-invasive method.

Utility of the hyperventilation test in the evaluation of the dizzy patient.

PubMed

Califano, Luigi; Mazzone, Salvatore; Salafia, Francesca

2013-10-01

The aim of the review is to value the incidence, patterns and temporal characteristics of hyperventilation-induced nystagmus (HVIN) in patients suffering from vestibular diseases, as well as its contribution to the differential diagnosis between vestibular neuritis and schwannoma of the eighth cranial nerve and its behavior in some central vestibular diseases. The hyperventilation test seems to be more useful than other bedside tests in detecting schwannoma of the eighth cranial nerve in the case of sudden monolateral hypacusia. The presence of an excitatory pattern of HVIN in vestibular schwannoma that has undergone to stereotactic surgery reveals that this therapy produces demyelinization in neural fibers. The hyperventilation test is easy to perform, well tolerated and able to reveal latent vestibular asymmetries; it acts both at peripheral and central vestibular levels through metabolic mechanisms or, more rarely, through changes in cerebrospinal fluid pressure. It can provide patterns of oculomotor responses suggesting the execution of gadolinium-enhanced MRI, upon the suspicion of schwannoma of the eighth cranial nerve or of a central disease. In our opinion, the presence of HVIN always needs to be viewed within the more general context of a complete examination of auditory and vestibular systems.

[Which treatments for the hyperventilation syndrome in adults?

PubMed

Rapin, A; Deslee, G; Percebois-Macadre, L; Jonvel, A-C; Demangeon, S; Boyer, F C

2017-02-01

The hyperventilation syndrome is a complex entity whose management is poorly codified. We report a synthesis about the management of adult patients diagnosed with hyperventilation syndrome. A systematic literature review has identified fifteen articles dealing, among them three studies about drug treatment and the others about non-pharmacological approaches. Among the last ones, a re-educational approach based on abdominal ventilation and regulation of the ventilatory rate seems and an educative approach seems to be the most effective. Methodological biases did not permit a conclusion on the efficacy of these treatments. Practically, teaching abdominal ventilation and respiratory rate regulation, associated with a personalized therapeutic education, seems to be a pertinent management approach. Other clinical studies should explore this issue. Copyright © 2016 SPLF. Published by Elsevier Masson SAS. All rights reserved.

Theoretical effect of hyperventilation on speed of recovery and risk of rehypnotization following recovery - a GasMan® simulation

PubMed Central

2012-01-01

Background Hyperventilation may be used to hasten recovery from general anesthesia with potent inhaled anesthetics. However, its effect may be less pronounced with the newer, less soluble agents, and it may result in rehypnotization if subsequent hypoventilation occurs because more residual anesthetic will be available in the body for redistribution to the central nervous system. We used GasMan® simulations to examine these issues. Methods One MAC of isoflurane, sevoflurane, or desflurane was administered to a fictitious 70 kg patient for 8 h with normoventilation (alveolar minute ventilation [VA] 5 L.min-1), resulting in full saturation of the vessel rich group (VRG) and >95% saturation of the muscle group. After 8 h, agent administration was stopped, and fresh gas flow was increased to 10 L.min-1 to avoid rebreathing. At that same time, we continued with one simulation where normoventilation was maintained, while in a second simulation hyperventilation was instituted (10 L.min-1). We determined the time needed for the partial pressure in the VRG (FVRG; representing the central nervous system) to reach 0.3 MAC (MACawake). After reaching MACawake in the VRG, several degrees of hypoventilation were instituted (VA of 2.5, 1.5, 1, and 0.5 L.min-1) to determine whether FVRG would increase above 0.3 MAC(= rehypnotization). Results Time to reach 0.3 MAC in the VRG with normoventilation was 14 min 42 s with isoflurane, 9 min 12 s with sevoflurane, and 6 min 12 s with desflurane. Hyperventilation reduced these recovery times by 30, 18, and 13% for isoflurane, sevoflurane, and desflurane, respectively. Rehypnotization was observed with VA of 0.5 L.min-1 with desflurane, 0.5 and 1 L.min-1 with sevoflurane, and 0.5, 1, 1.5, and 2.5 L.min-1 with isoflurane. Only with isoflurane did initial hyperventilation slightly increase the risk of rehypnotization. Conclusions These GasMan® simulations confirm that the use of hyperventilation to hasten recovery is marginally beneficial with the newer, less soluble agents. In addition, subsequent hypoventilation results in rehypnotization only with more soluble agents, unless hypoventilation is severe. Also, initial hyperventilation does not increase the risk of rehypnotization with less soluble agents when subsequent hypoventilation occurs. Well-controlled clinical studies are required to validate these simulations. PMID:22989260

Theoretical effect of hyperventilation on speed of recovery and risk of rehypnotization following recovery - a GasMan® simulation.

PubMed

De Wolf, Andre M; Van Zundert, Tom C; De Cooman, Sofie; Hendrickx, Jan F

2012-09-18

Hyperventilation may be used to hasten recovery from general anesthesia with potent inhaled anesthetics. However, its effect may be less pronounced with the newer, less soluble agents, and it may result in rehypnotization if subsequent hypoventilation occurs because more residual anesthetic will be available in the body for redistribution to the central nervous system. We used GasMan® simulations to examine these issues. One MAC of isoflurane, sevoflurane, or desflurane was administered to a fictitious 70 kg patient for 8 h with normoventilation (alveolar minute ventilation [VA] 5 L.min-1), resulting in full saturation of the vessel rich group (VRG) and >95% saturation of the muscle group. After 8 h, agent administration was stopped, and fresh gas flow was increased to 10 L.min-1 to avoid rebreathing. At that same time, we continued with one simulation where normoventilation was maintained, while in a second simulation hyperventilation was instituted (10 L.min-1). We determined the time needed for the partial pressure in the VRG (FVRG; representing the central nervous system) to reach 0.3 MAC (MACawake). After reaching MACawake in the VRG, several degrees of hypoventilation were instituted (VA of 2.5, 1.5, 1, and 0.5 L.min-1) to determine whether FVRG would increase above 0.3 MAC(= rehypnotization). Time to reach 0.3 MAC in the VRG with normoventilation was 14 min 42 s with isoflurane, 9 min 12 s with sevoflurane, and 6 min 12 s with desflurane. Hyperventilation reduced these recovery times by 30, 18, and 13% for isoflurane, sevoflurane, and desflurane, respectively. Rehypnotization was observed with VA of 0.5 L.min-1 with desflurane, 0.5 and 1 L.min-1 with sevoflurane, and 0.5, 1, 1.5, and 2.5 L.min-1 with isoflurane. Only with isoflurane did initial hyperventilation slightly increase the risk of rehypnotization. These GasMan® simulations confirm that the use of hyperventilation to hasten recovery is marginally beneficial with the newer, less soluble agents. In addition, subsequent hypoventilation results in rehypnotization only with more soluble agents, unless hypoventilation is severe. Also, initial hyperventilation does not increase the risk of rehypnotization with less soluble agents when subsequent hypoventilation occurs. Well-controlled clinical studies are required to validate these simulations.

[Artificial hyperventilation in head injury. I. Spontaneous hyperventilation and assisted ventilation (author's transl)].

PubMed

Katsurada, K; Ogawa, M; Minami, T

1975-02-01

The present study was desined to clarify the roles of artificial hyperventilation in management of the patients with cerebral injury. Here reported is the first part of the serial studies and concerned with general informations about hyperventilation. The measurements of PaCO2, minute ventilation volume (VE), dead space (VD), tidal volume (VT), cardiac output (by dye dilution method), oxygen consumption (by Fick' principle) and oxygen equilibrium were performed in the patients suffering from acute, severe head injury. And the effect of assisted ventilation on them were investigated (using pressure-limited respirator). 1. There was a common finding that marked and sustained increase in VE, VA (alveolar ventilation), and decrease in PaCO2 existed during the first week of injury. 97% of both VE and VA were above normal and mean value of PaCO2 was 29-33 mmHg. The syndrome of spontaneous hyperventilation was evidently more prominent in the nonsurvived group of patients. It was noteworthy that increased VE (or VA) was dependent neither on VD or pulmonary dysfunction nor on metabolic acidosis of arterial blood. The relation of VA to base excess in head injury was well contrasted to that of acute CO poisoning. 2. Assisted ventilation resulted in increased VT and decreased respiratory rate, and little change in VE. Consequently, PaCO2 changed only from 33.0 to 29.4 mmHg as a mean of entire series of patients. But when the influence affected by hypoxemic drive was subsided, a significant reduction of PaCO2 was disclosed following assisted ventilation. The assisted ventilation with pure oxygen was also associated with reduced cardiac output (from 6.0l/min to 5.3l/min), though the oxygen consumption changed variedly among the patients. 3. The fact was confirmed that both hypocapnea and alkalosis produced the left-sised shift of oxygen dissociation curve, decrease in P50 (P02 at 50% saturation of oxygen), and in addition, narrowed arterio-mixed venous oxygen difference. The changes of artero-mixed venous oxygen saturation difference which were calculated at 100 mmHg of PaO2 and 40mmHg of mixed venous PO2 were in a linear fashion with those of P50. Apart from the problems on injured brain, the beneficial and non-beneficial effects of hyperventilation were further discussed. The availability and inidcation of artificial hyperventilation should be precisely evaluated later, in a comprehensive manner with the subsequent studies (Part 2 and 3) on cerebral metabolism and intracranial pressure.

Panic-related hyperventilation resulting in hypophosphataemia and a high lactate

PubMed Central

Suarez, Nicolas; Conway, Nerys; Pickett, Tom

2013-01-01

A 22-year-old lady presented to the emergency department with dyspnoea and pleuritic chest pain. Life-threatening asthma, pulmonary embolus and pneumothorax were all excluded. However, investigations did show an unexplained hypophosphataemia and raised lactate, both of which were subsequently attributed to hyperventilation with a component of panic. Here we explore the mechanism of these findings and the management of hypophosphataemia. PMID:23667220

Panic-related hyperventilation resulting in hypophosphataemia and a high lactate.

PubMed

Suarez, Nicolas; Conway, Nerys; Pickett, Tom

2013-05-09

A 22-year-old lady presented to the emergency department with dyspnoea and pleuritic chest pain. Life-threatening asthma, pulmonary embolus and pneumothorax were all excluded. However, investigations did show an unexplained hypophosphataemia and raised lactate, both of which were subsequently attributed to hyperventilation with a component of panic. Here we explore the mechanism of these findings and the management of hypophosphataemia.

Breathing Maneuvers as a Vasoactive Stimulus for Detecting Inducible Myocardial Ischemia – An Experimental Cardiovascular Magnetic Resonance Study

PubMed Central

Fischer, Kady; Guensch, Dominik P; Shie, Nancy; Lebel, Julie; Friedrich, Matthias G

2016-01-01

Background Breathing maneuvers can elicit a similar vascular response as vasodilatory agents like adenosine; yet, their potential diagnostic utility in the presence of coronary artery stenosis is unknown. The objective of the study is to investigate if breathing maneuvers can non-invasively detect inducible ischemia in an experimental animal model when the myocardium is imaged with oxygenation-sensitive cardiovascular magnetic resonance (OS-CMR). Methods and Findings In 11 anesthetised swine with experimentally induced significant stenosis (fractional flow reserve <0.75) of the left anterior descending coronary artery (LAD) and 9 control animals, OS-CMR at 3T was performed during two different breathing maneuvers, a long breath-hold; and a combined maneuver of 60s of hyperventilation followed by a long breath-hold. The resulting change of myocardial oxygenation was compared to the invasive measurements of coronary blood flow, blood gases, and oxygen extraction. In control animals, all breathing maneuvers could significantly alter coronary blood flow as hyperventilation decreased coronary blood flow by 34±23%. A long breath-hold alone led to an increase of 97±88%, while the increase was 346±327% (p<0.001), when the long breath-hold was performed after hyperventilation. In stenosis animals, the coronary blood flow response was attenuated after both hyperventilation and the following breath-hold. This was matched by the observed oxygenation response as breath-holds following hyperventilation consistently yielded a significant difference in the signal of the MRI images between the perfusion territory of the stenosis LAD and remote myocardium. There was no difference between the coronary territories during the other breathing maneuvers or in the control group at any point. Conclusion In an experimental animal model, the response to a combined breathing maneuver of hyperventilation with subsequent breath-holding is blunted in myocardium subject to significant coronary artery stenosis. This maneuver may allow for detecting severe coronary artery stenosis and have a significant clinical potential as a non-pharmacological method for diagnostic testing in patients with suspected coronary artery disease. PMID:27741282

Cerebral Hemodynamic Effects of Acute Hyperoxia and Hyperventilation after Severe Traumatic Brain Injury

PubMed Central

Rangel-Castilla, Leonardo; Lara, Lucia Rivera; Gopinath, Shankar; Swank, Paul R.; Valadka, Alex

2010-01-01

Abstract The purpose of this study was to examine the effects of hyperventilation or hyperoxia on cerebral hemodynamic parameters over time in patients with severe traumatic brain injury (TBI). We prospectively studied 186 patients with severe TBI. CO2 and O2 reactivity tests were conducted twice a day on days 1–5 and once daily on days 6–10 after injury. During hyperventilation there was a significant decrease in intracranial pressure (ICP), mean arterial pressure (MAP), jugular venous oxygen saturation (Sjvo2), brain tissue Po2 (Pbto2), and flow velocity (FV). During hyperoxia there was an increase in Sjvo2 and Pbto2, and a small but consistent decrease in ICP, end-tidal carbon dioxide (etco2), partial arterial carbon dioxide pressure (Paco2), and FV. Brain tissue oxygen reactivity during the first 12 h after injury averaged 19.7 ± 3.0%, and slowly decreased over the next 7 days. The autoregulatory index (ARI; normal = 5.3 ± 1.3) averaged 2.2 ± 1.5 on day 1 post-injury, and gradually improved over the 10 days of monitoring. The ARI significantly improved during hyperoxia, by an average of 0.4 ± 1.8 on the left, and by 0.5 ± 1.8 on the right. However, the change in ARI with hyperoxia was much smaller than that observed with hyperventilation. Hyperventilation increased ARI by an average of 1.3 ± 1.9 on the left, and 1.5 ± 2.0 on the right. Pressure autoregulation, as assessed by dynamic testing, was impaired in these head-injured patients. Acute hyperoxia significantly improved pressure autoregulation, although the effect was smaller than that induced by hyperventilation. The very small change in Paco2 induced by hyperoxia does not appear to explain this finding. Rather, the vasoconstriction induced by acute hyperoxia may allow the cerebral vessels to respond better to transient hypotension. Further studies are needed to define the clinical significance of these observations. PMID:20684672

Hyperventilation and exhaustion syndrome.

PubMed

Ristiniemi, Heli; Perski, Aleksander; Lyskov, Eugene; Emtner, Margareta

2014-12-01

Chronic stress is among the most common diagnoses in Sweden, most commonly in the form of exhaustion syndrome (ICD-10 classification - F43.8). The majority of patients with this syndrome also have disturbed breathing (hyperventilation). The aim of this study was to investigate the association between hyperventilation and exhaustion syndrome. Thirty patients with exhaustion syndrome and 14 healthy subjects were evaluated with the Nijmegen Symptom Questionnaire (NQ). The participants completed questionnaires about exhaustion, mental state, sleep disturbance, pain and quality of life. The evaluation was repeated 4 weeks later, after half of the patients and healthy subjects had engaged in a therapy method called 'Grounding', a physical exercise inspired by African dance. The patients reported significantly higher levels of hyperventilation as compared to the healthy subjects. All patients' average score on NQ was 26.57 ± 10.98, while that of the healthy subjects was 15.14 ± 7.89 (t = -3.48, df = 42, p < 0.001). The NQ scores correlated strongly with two measures of exhaustion (Karolinska Exhaustion Scale KES r = 0.772, p < 0.01; Shirom Melamed Burnout Measure SMBM r = 0.565, p < 0.01), mental status [Hospital Anxiety and Depression Score (HADS) depression r = 0.414, p < 0.01; HADS anxiety r = 0.627, p < 0.01], sleep disturbances (r = -0.514, p < 0.01), pain (r = -.370, p < 0.05) and poor well-being (Medical Outcomes Survey Short Form 36 questionnaire- SR Health r = -0.529, p < 0.05). In the logistic regression analysis, the variance in the scores from NQ were explained to a high degree (R(2) = 0.752) by scores in KES and HADS. The brief Grounding training contributed to a near significant reduction in hyperventilation (F = 2.521, p < 0.124) and to significant reductions in exhaustion scores and scores of depression and anxiety. The conclusion is that hyperventilation is common in exhaustion syndrome patients and that it can be reduced by systematic physical therapy such as Grounding. © 2013 The Authors. Scandinavian Journal of Caring Sciences published by John Wiley & Sons Ltd on behalf of Nordic College of Caring Science.

Enhancement on Wingate Anaerobic Test Performance With Hyperventilation.

PubMed

Leithäuser, Renate M; Böning, Dieter; Hütler, Matthias; Beneke, Ralph

2016-07-01

Relatively long-lasting metabolic alkalizing procedures such as bicarbonate ingestion have potential for improving performance in long-sprint to middle-distance events. Within a few minutes, hyperventilation can induce respiratory alkalosis. However, corresponding performance effects are missing or equivocal at best. To test a potential performance-enhancing effect of respiratory alkalosis in a 30-s Wingate Anaerobic Test (WAnT). 10 men (mean ± SD age 26.6 ± 4.9 y, height 184.4 ± 6.1 cm, body-mass test 1 80.7 ± 7.7 kg, body-mass test 2 80.4 ± 7.2 kg, peak oxygen uptake 3.95 ± 0.43 L/min) performed 2 WAnTs, 1 with and 1 without a standardized 15-min hyperventilation program pre-WAnT in randomized order separated by 1 wk. Compared with the control condition, hyperventilation reduced (all P < .01) pCO2 (40.5 ± 2.8 vs 22.5 ± 1.6 mm Hg) and HCO3 - (25.5 ± 1.7 vs 22.7 ± 1.6 mmol/L) and increased (all P < .01) pH (7.41 ± 0.01 vs 7.61 ± 0.03) and actual base excess (1.4 ± 1.4 vs 3.2 ± 1.6 mmol/L) pre-WAnT with an ergogenic effect on WAnT average power (681 ± 41 vs 714 ± 44 W) and total metabolic energy (138 ± 12 vs. 144 ± 13 kJ) based on an increase in glycolytic energy (81 ± 13 vs 88 ± 13 kJ). Hyperventilation-induced respiratory alkalosis can enhance WAnT cycling sprint performance well in the magnitude of what is seen after successful bicarbonate ingestion.

Metabolic acidosis as an underlying mechanism of respiratory distress in children with severe acute asthma.

PubMed

Meert, Kathleen L; Clark, Jeff; Sarnaik, Ashok P

2007-11-01

1) To alert the clinician that increasing rate and depth of breathing during treatment of acute asthma may be a manifestation of metabolic acidosis with hyperventilation rather than worsening airway obstruction; and 2) to describe the frequency of metabolic acidosis with hyperventilation in children with severe acute asthma admitted to our pediatric intensive care unit. Retrospective medical record review. University-affiliated children's hospital. All patients admitted to the pediatric intensive care unit with a diagnosis of asthma between January 1, 2005, and December 31, 2005. None. Fifty-three patients with asthma (median age 7.8 yrs, range 0.7-17.9 yrs; 35 [66%] male; 46 [87%] black and 7 [13%] white) were admitted to the pediatric intensive care unit during the study period. Fifteen (28%) patients developed metabolic acidosis with hyperventilation (pH <7.35, Pco2 <35 torr [4.6 kPa], and base excess < or = -7 mmol/L) during their hospital course. Of these, lactic acid was assessed in four patients and was elevated in each; all had hyperglycemia (blood glucose >120 mg/dL [6.7 mmol/L]). Patients who developed metabolic acidosis with hyperventilation received asthma therapy similar to that received by patients who did not develop the disorder. Metabolic acidosis resolved contemporaneously with tapering of beta2-adrenergic agonists and administration of supportive care. All patients survived. Metabolic acidosis with hyperventilation manifesting as respiratory distress can occur in children with severe acute asthma. A pathophysiologic rationale exists for the contribution of beta2-adrenergic agents to the development of this acid-base disorder. Failure to recognize metabolic acidosis as the underlying mechanism of respiratory distress may lead to inappropriate intensification of bronchodilator therapy. Supportive care and tapering of beta2-adrenergic agents are recommended to resolve this condition.

Preventing and Treating Hypoxia: Using a Physiology Simulator to Demonstrate the Value of Pre-Oxygenation and the Futility of Hyperventilation.

PubMed

Lerant, Anna A; Hester, Robert L; Coleman, Thomas G; Phillips, William J; Orledge, Jeffrey D; Murray, W Bosseau

2015-01-01

Insufficient pre-oxygenation before emergency intubation, and hyperventilation after intubation are mistakes that are frequently observed in and outside the operating room, in clinical practice and in simulation exercises. Physiological parameters, as appearing on standard patient monitors, do not alert to the deleterious effects of low oxygen saturation on coronary perfusion, or that of low carbon dioxide concentrations on cerebral perfusion. We suggest the use of HumMod, a computer-based human physiology simulator, to demonstrate beneficial physiological responses to pre-oxygenation and the futility of excessive minute ventilation after intubation. We programmed HumMod, to A.) compare varying times (0-7 minutes) of pre-oxygenation on oxygen saturation (SpO2) during subsequent apnoea; B.) simulate hyperventilation after apnoea. We compared the effect of different minute ventilation rates on SpO2, acid-base status, cerebral perfusion and other haemodynamic parameters. A.) With no pre-oxygenation, starting SpO2 dropped from 98% to 90% in 52 seconds with apnoea. At the other extreme, following full pre-oxygenation with 100% O2 for 3 minutes or more, the SpO2 remained 100% for 7.75 minutes during apnoea, and dropped to 90% after another 75 seconds. B.) Hyperventilation, did not result in more rapid normalization of SpO2, irrespective of the level of minute ventilation. However, hyperventilation did cause significant decreases in cerebral blood flow (CBF). HumMod accurately simulates the physiological responses compared to published human studies of pre-oxygenation and varying post intubation minute ventilations, and it can be used over wider ranges of parameters than available in human studies and therefore available in the literature.

Aging blunts hyperventilation-induced hypocapnia and reduction in cerebral blood flow velocity during maximal exercise.

PubMed

Marsden, K R; Haykowsky, M J; Smirl, J D; Jones, H; Nelson, M D; Altamirano-Diaz, Luis A; Gelinas, J C; Tzeng, Y C; Smith, K J; Willie, C K; Bailey, D M; Ainslie, P N

2012-06-01

Cerebral blood flow (CBF) increases from rest to ∼60% of peak oxygen uptake (VO(2peak)) and thereafter decreases towards baseline due to hyperventilation-induced hypocapnia and subsequent cerebral vasoconstriction. It is unknown what happens to CBF in older adults (OA), who experience a decline in CBF at rest coupled with a blunted ventilatory response during VO(2peak). In 14 OA (71 ± 10 year) and 21 young controls (YA; 23 ± 4 years), we hypothesized that OA would experience less hyperventilation-induced cerebral vasoconstriction and therefore an attenuated reduction in CBF at VO(2peak). Incremental exercise was performed on a cycle ergometer, whilst bilateral middle cerebral artery blood flow velocity (MCA V (mean); transcranial Doppler ultrasound), heart rate (HR; ECG) and end-tidal PCO(2) (P(ET)CO(2)) were monitored continuously. Blood pressure (BP) was monitored intermittently. From rest to 50% of VO(2peak), despite greater elevations in BP in OA, the change in MCA V(mean) was greater in YA compared to OA (28% vs. 15%, respectively; P < 0.0005). In the YA, at intensities >70% of VO(2peak), the hyperventilation-induced declines in both P(ET)CO(2) (14 mmHg (YA) vs. 4 mmHg (OA); P < 0.05) and MCA V(mean) (-21% (YA) vs. -7% (OA); P < 0.0005) were greater in YA compared to OA. Our findings show (1), from rest-to-mild intensity exercise (50% VO(2peak)), elevations in CBF are reduced in OA and (2) age-related declines in hyperventilation during maximal exercise result in less hypocapnic-induced cerebral vasoconstriction.

Individuality of breathing during volitional moderate hyperventilation.

PubMed

Besleaga, Tudor; Blum, Michaël; Briot, Raphaël; Vovc, Victor; Moldovanu, Ion; Calabrese, Pascale

2016-01-01

The aim of this study is to investigate the individuality of airflow shapes during volitional hyperventilation. Ventilation was recorded on 18 healthy subjects following two protocols: (1) spontaneous breathing (SP1) followed by a volitional hyperventilation at each subject's spontaneous (HVSP) breathing rate, (2) spontaneous breathing (SP2) followed by hyperventilation at 20/min (HV20). HVSP and HV20 were performed at the same level of hypocapnia: end tidal CO2 (FETCO2) was maintained at 1% below the spontaneous level. At each breath, the tidal volume (VT), the breath (TTOT), the inspiratory (TI) and expiratory durations, the minute ventilation, VT/TI, TI/TTOT and the airflow shape were quantified by harmonic analysis. Under different conditions of breathing, we test if the airflow profiles of the same individual are more similar than airflow profiles between individuals. Minute ventilation was not significantly different between SP1 (6.71 ± 1.64 l·min(-1)) and SP2 (6.57 ± 1.31 l·min(-1)) nor between HVSP (15.88 ± 4.92 l·min(-1)) and HV20 (15.87 ± 4.16 l·min(-1)). Similar results were obtained for FETCO2 between SP1 (5.06 ± 0.54 %) and SP2 (5.00 ± 0.51%), and HVSP (4.07 ± 0.51%) and HV20 (3.88 ± 0.42%). Only TI/TTOT remained unchanged in all four conditions. Airflow shapes were similar when comparing SP1-SP2, HVSP-HV20, and SP1-HVSP but not similar when comparing SP2-HV20. These results suggest the existence of an individuality of airflow shape during volitional hyperventilation. We conclude that volitional ventilation alike automatic breathing follows inherent properties of the ventilatory system. Registered by Pascale Calabrese on ClinicalTrials.gov, # NCT01881945.

Preventing and Treating Hypoxia: Using a Physiology Simulator to Demonstrate the Value of Pre-Oxygenation and the Futility of Hyperventilation

PubMed Central

Lerant, Anna A.; Hester, Robert L.; Coleman, Thomas G.; Phillips, William J.; Orledge, Jeffrey D.; Murray, W. Bosseau

2015-01-01

Introduction: Insufficient pre-oxygenation before emergency intubation, and hyperventilation after intubation are mistakes that are frequently observed in and outside the operating room, in clinical practice and in simulation exercises. Physiological parameters, as appearing on standard patient monitors, do not alert to the deleterious effects of low oxygen saturation on coronary perfusion, or that of low carbon dioxide concentrations on cerebral perfusion. We suggest the use of HumMod, a computer-based human physiology simulator, to demonstrate beneficial physiological responses to pre-oxygenation and the futility of excessive minute ventilation after intubation. Methods: We programmed HumMod, to A.) compare varying times (0-7 minutes) of pre-oxygenation on oxygen saturation (SpO2) during subsequent apnoea; B.) simulate hyperventilation after apnoea. We compared the effect of different minute ventilation rates on SpO2, acid-base status, cerebral perfusion and other haemodynamic parameters. Results: A.) With no pre-oxygenation, starting SpO2 dropped from 98% to 90% in 52 seconds with apnoea. At the other extreme, following full pre-oxygenation with 100% O2 for 3 minutes or more, the SpO2 remained 100% for 7.75 minutes during apnoea, and dropped to 90% after another 75 seconds. B.) Hyperventilation, did not result in more rapid normalization of SpO2, irrespective of the level of minute ventilation. However, hyperventilation did cause significant decreases in cerebral blood flow (CBF). Conclusions: HumMod accurately simulates the physiological responses compared to published human studies of pre-oxygenation and varying post intubation minute ventilations, and it can be used over wider ranges of parameters than available in human studies and therefore available in the literature. PMID:26283881

Leigh syndrome in individuals bearing m.9185T>C MTATP6 variant. Is hyperventilation a factor which starts its development?

PubMed

Piekutowska-Abramczuk, Dorota; Rutyna, Rafał; Czyżyk, Elżbieta; Jurkiewicz, Elżbieta; Iwanicka-Pronicka, Katarzyna; Rokicki, Dariusz; Stachowicz, Sylwia; Strzemecka, Joanna; Guz, Wiesław; Gawroński, Michał; Kosierb, Aneta; Ligas, Joanna; Puchala, Mateusz; Drelich-Zbroja, Anna; Bednarska-Makaruk, Małgorzata; Dąbrowski, Wojciech; Ciara, Elżbieta; Książyk, Janusz B; Pronicka, Ewa

2018-02-01

Leigh syndrome (LS), subacute necrotizing encephalomyelopathy is caused by various genetic defects, including m.9185T>C MTATP6 variant. Mechanism of LS development remains unknown. We report on the acid-base status of three patients with m.9185T>C related LS. At the onset, it showed respiratory alkalosis, reflecting excessive respiration effort (hyperventilation with low pCO 2 ). In patient 1, the deterioration occurred in temporal relation to passive oxygen therapy. To the contrary, on the recovery, she demonstrated a relatively low respiratory drive, suggesting that a "hypoventilation" might be beneficial for m.9185T>C carriers. As long as circumstances of the development of LS have not been fully explained, we recommend to counteract hyperventilation and carefully dose oxygen in patients with m.9185T>C related LS.

Interoceptive threat leads to defensive mobilization in highly anxiety sensitive persons.

PubMed

Melzig, Christiane A; Holtz, Katharina; Michalowski, Jaroslaw M; Hamm, Alfons O

2011-06-01

To study defensive mobilization elicited by the exposure to interoceptive arousal sensations, we exposed highly anxiety sensitive students to a symptom provocation task. Symptom reports, autonomic arousal, and the startle eyeblink response were monitored during guided hyperventilation and a recovery period in 26 highly anxiety sensitive persons and 22 controls. Normoventilation was used as a non-provocative comparison condition. Hyperventilation led to autonomic arousal and a marked increase in somatic symptoms. While high and low anxiety sensitive persons did not differ in their defensive activation during hyperventilation, group differences were detected during early recovery. Highly anxiety sensitive students exhibited a potentiation of startle response magnitudes and increased autonomic arousal after hyper- as compared to after normoventilation, indicating defensive mobilization evoked by the prolonged presence of feared somatic sensations. Copyright © 2010 Society for Psychophysiological Research.

Hyperventilation of pregnancy presenting with flaccid quadriparesis due to hypokalaemia secondary to respiratory alkalosis.

PubMed

Santra, Gouranga; Paul, Rudrajit; Das, Shubhabrata; Pradhan, Sourav

2014-06-01

Hyperventilation in pregnancy is a cause of chronic respiratory alkalosis. Alkalosis either metabolic or respiratory may cause intracellular shift of potassium ions that may lead to hypokalaemia. However, the resultant hypokalaemia in respiratory alkalosis is usually mild and does not cause much clinical features. A five-months-pregnant female of the age 25 years presented with sudden onset flaccid weakness of both lower limbs associated with thigh muscle pain followed by weakness of both upper limbs within three days. Subsequent investigation revealed severe hypokalaemia due to acute exacerbation of chronic respiratory alkalosis secondary to hyperventilation of pregnancy, other causes of hypokalaemia being ruled out. Respiratory alkalosis causes tetany and other clinical manifestations. But hypokalaemia and such weakness is rarely found. Thisis probably the first report of this type from India.

The effect of centrally injected CDP-choline on respiratory system; involvement of phospholipase to thromboxane signaling pathway.

PubMed

Topuz, Bora B; Altinbas, Burcin; Yilmaz, Mustafa S; Saha, Sikha; Batten, Trevor F; Savci, Vahide; Yalcin, Murat

2014-05-01

CDP-choline is an endogenous metabolite in phosphatidylcholine biosynthesis. Exogenous administration of CDP-choline has been shown to affect brain metabolism and to exhibit cardiovascular, neuroendocrine neuroprotective actions. On the other hand, little is known regarding its respiratory actions and/or central mechanism of its respiratory effect. Therefore the current study was designed to investigate the possible effects of centrally injected CDP-choline on respiratory system and the mediation of the central cholinergic receptors and phospholipase to thromboxane signaling pathway on CDP-choline-induced respiratory effects in anaesthetized rats. Intracerebroventricularly (i.c.v.) administration of CDP-choline induced dose- and time-dependent increased respiratory rates, tidal volume and minute ventilation of male anaesthetized Spraque Dawley rats. İ.c.v. pretreatment with atropine failed to alter the hyperventilation responses to CDP-choline whereas mecamylamine, cholinergic nicotinic receptor antagonist, mepacrine, phospholipase A2 inhibitor, and neomycin phospholipase C inhibitor, blocked completely the hyperventilation induced by CDP-choline. In addition, central pretreatment with furegrelate, thromboxane A2 synthesis inhibitor, also partially blocked CDP-choline-evoked hyperventilation effects. These data show that centrally administered CDP-choline induces hyperventilation which is mediated by activation of central nicotinic receptors and phospholipase to thromboxane signaling pathway. Copyright © 2014 Elsevier B.V. All rights reserved.

Hyperventilation Therapy for Control of Posttraumatic Intracranial Hypertension

PubMed Central

Godoy, Daniel Agustín; Seifi, Ali; Garza, David; Lubillo-Montenegro, Santiago; Murillo-Cabezas, Francisco

2017-01-01

During traumatic brain injury, intracranial hypertension (ICH) can become a life-threatening condition if it is not managed quickly and adequately. Physicians use therapeutic hyperventilation to reduce elevated intracranial pressure (ICP) by manipulating autoregulatory functions connected to cerebrovascular CO2 reactivity. Inducing hypocapnia via hyperventilation reduces the partial pressure of arterial carbon dioxide (PaCO2), which incites vasoconstriction in the cerebral resistance arterioles. This constriction decrease cerebral blood flow, which reduces cerebral blood volume and, ultimately, decreases the patient’s ICP. The effects of therapeutic hyperventilation (HV) are transient, but the risks accompanying these changes in cerebral and systemic physiology must be carefully considered before the treatment can be deemed advisable. The most prominent criticism of this approach is the cited possibility of developing cerebral ischemia and tissue hypoxia. While it is true that certain measures, such as cerebral oxygenation monitoring, are needed to mitigate these dangerous conditions, using available evidence of potential poor outcomes associated with HV as justification to dismiss the implementation of therapeutic HV is debatable and remains a controversial subject among physicians. This review highlights various issues surrounding the use of HV as a means of controlling posttraumatic ICH, including indications for treatment, potential risks, and benefits, and a discussion of what techniques can be implemented to avoid adverse complications. PMID:28769857

[Poor tolerance of exertion during sports and bronchial hyperreactivity].

PubMed

Potiron-Josse, M; Boutet, S; Ginet, J

1992-11-01

135 sportsmen and women, 55 girls, 80 boys, aged from 7 to 30 years, from various sports, who complained of bad tolerance of exertion were examined with an exercise test and isocapnic spontaneous hyperventilation. 61, about 45%, during a hyperventilation test had a fall of V.E.M.S. greater than or equal to 20%, showing bronchial hyperreactivity. After three tests, this fall index was greater than or equal to 50%. 68% of the positive responses were seen in boys and 2/3 of the subjects with a positive response were atopics. No other argument could be maintained from the questioning or clinical history to predict the positive or negative character of the hyperventilation (age, sporting level, symptoms, previous asthma or asthmatic, allergy). H.S.V.I. of the chests of a sporting population that complains of exertion intolerance, therefore allows verification of an H.R.B. assessment of its severity and to follow evolution after treatment.

Tissue Pulsatility Imaging of Cerebral Vasoreactivity during Hyperventilation

PubMed Central

Kucewicz, John C.; Dunmire, Barbrina; Giardino, Nicholas D.; Leotta, Daniel F.; Paun, Marla; Dager, Stephen R.; Beach, Kirk W.

2008-01-01

Tissue Pulsatility Imaging (TPI) is an ultrasonic technique that is being developed at the University of Washington to measure tissue displacement or strain due to blood flow over the cardiac and respiratory cycles. This technique is based in principle on plethysmography, an older non-ultrasound technology for measuring expansion of a whole limb or body part due to perfusion. TPI adapts tissue Doppler signal processing methods to measure the “plethysmographic” signal from hundreds or thousands of sample volumes in an ultrasound image plane. This paper presents a feasibility study to determine if TPI can be used to assess cerebral vasoreactivity. Ultrasound data were collected transcranially through the temporal acoustic window from four subjects before, during, and after voluntary hyperventilation. In each subject, decreases in tissue pulsatility during hyperventilation were observed that were statistically correlated with the subject’s end-tidal CO2 measurements. PMID:18336991

Hyperventilation and cold-pressor stress echocardiography combined with automated functional imaging non-invasively detected vasospastic angina

PubMed Central

Suzuki, Kengo; Akashi, Yoshihiro J; Mizukoshi, Kei; Kou, Seisyou; Takai, Manabu; Izumo, Masaki; Shimozato, Takashi; Hayashi, Akio; Ohtaki, Eiji; Nobuoka, Sachihiko; Miyake, Fumihiko

2010-01-01

A 47-year-old male presented with chest discomfort while sleeping. The patient was suspected of having vasospastic angina (VSA) and underwent hyperventilation and cold-pressor stress echocardiography. No chest pain, ECG changes or decreased wall motion was found. However, automated function imaging (AFI) showed decreased peak systolic strain at the apex and postsystolic shortening at both the apex and inferior wall, which was not found before the test. The provocation test revealed 99% stenosis in the right coronary artery #2 at a dose of 50 μg acetylcholine and 90% stenosis in the left coronary artery #8 at a dose of 100 μg. The patient was thus diagnosed as having VSA. The present case demonstrates the usefulness of AFI combined with hyperventilation and cold-pressor stress echocardiography as a screening examination for VSA. PMID:22798093

Hyperventilation and exhaustion syndrome

PubMed Central

Ristiniemi, Heli; Perski, Aleksander; Lyskov, Eugene; Emtner, Margareta

2014-01-01

Chronic stress is among the most common diagnoses in Sweden, most commonly in the form of exhaustion syndrome (ICD-10 classification – F43.8). The majority of patients with this syndrome also have disturbed breathing (hyperventilation). The aim of this study was to investigate the association between hyperventilation and exhaustion syndrome. Thirty patients with exhaustion syndrome and 14 healthy subjects were evaluated with the Nijmegen Symptom Questionnaire (NQ). The participants completed questionnaires about exhaustion, mental state, sleep disturbance, pain and quality of life. The evaluation was repeated 4 weeks later, after half of the patients and healthy subjects had engaged in a therapy method called ‘Grounding’, a physical exercise inspired by African dance. The patients reported significantly higher levels of hyperventilation as compared to the healthy subjects. All patients’ average score on NQ was 26.57 ± 10.98, while that of the healthy subjects was 15.14 ± 7.89 (t = −3.48, df = 42, p < 0.001). The NQ scores correlated strongly with two measures of exhaustion (Karolinska Exhaustion Scale KES r = 0.772, p < 0.01; Shirom Melamed Burnout Measure SMBM r = 0.565, p < 0.01), mental status [Hospital Anxiety and Depression Score (HADS) depression r = 0.414, p < 0.01; HADS anxiety r = 0.627, p < 0.01], sleep disturbances (r = −0.514, p < 0.01), pain (r = −.370, p < 0.05) and poor well-being (Medical Outcomes Survey Short Form 36 questionnaire- SR Health r = −0.529, p < 0.05). In the logistic regression analysis, the variance in the scores from NQ were explained to a high degree (R2 = 0.752) by scores in KES and HADS. The brief Grounding training contributed to a near significant reduction in hyperventilation (F = 2.521, p < 0.124) and to significant reductions in exhaustion scores and scores of depression and anxiety. The conclusion is that hyperventilation is common in exhaustion syndrome patients and that it can be reduced by systematic physical therapy such as Grounding. PMID:24134551

The Hyperventilation Syndrome - USSR -

DTIC Science & Technology

1960-07-28

elicited in all Patients a neurosis of the neurasthenic type and the absence of organ- ic changes of the nervous system. All patients were kept...capacity and maximum breathing capacity of the lungs in «*■ P"Ä^veS^^ «£? nation of the function of «^«»^JfgiJS during rest, oh- symptom is a...corti_ The hyperventilation syndrome ?®P™~;£ athenlc type of neur- cal impairment of respiration in a neurasthenic yv neuroses osis. It can be

Effects of massage therapy on anxiety, depression, hyperventilation and quality of life in HIV infected patients: A randomized controlled trial.

PubMed

Gregory, Reychler; Caty, Gilles; Aude, Arcq; Laurie, Lebrun; Leïla, Belkhir; Jean-Cyr, Yombi; Jean-Christophe, Marot

2017-06-01

HIV infection is often preceded or accompanied by psychiatric comorbidities. These disorders improve with complementary therapies. The aim of this study was to measure the effect of massage therapy on anxiety, depression, hyperventilation and quality of life in HIV infected patients. Adult HIV-infected patients were randomized (n=29) in massage therapy group (one hour a week during four weeks) and control group. Anxiety and depression (HADS-A and HADS-D), hyperventilation (Nijmegen questionnaire) and quality of life (WHOQOL-HIV) were evaluated at inclusion and after 4 weeks. At inclusion, 51% and 17% of the patients had a positive HADS-A and HADS-D score respectively. Two facets from WHOQOL-HIV ("Home environment" and "Death and dying" (p=0.04)) were different between groups. After the four week massage therapy, a significant improvement was observed only for Nijmegen questionnaire (p=0.01) and HADS-A (p=0.04) contrarily to WHOQOL-HIV and HADS-D. Domains of the WHOQOL-HIV did not improve following the massage therapy. Only "Pain and discomfort" facet improved after massage therapy (p=0.04). This study highlights the positive impact of a four week massage therapy on anxiety and hyperventilation in HIV infected patients. However, neither benefit of this program was observed on depression and quality of life. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effects of hyperventilation on axonal excitability parameters in patients with diabetes mellitus and polyneuropathy.

PubMed

Akça, Gökçen; Yerdelen, Deniz; Balcı, Mustafa Kemal; Uysal, Hilmi

2016-08-01

We aimed to explore axonal excitability parameters in patients with diabetes mellitus (DM) and polyneuropathy (PNP) as well as those without PNP. We used the short TROND protocol by QTRAC to measure axonal excitability parameters (strength-duration time constant (SDTC), rheobase, etc.) in 12 healthy subjects and 14 DM patients with PNP and 10 DM patients without PNP. The short TROND protocol was performed before and after 20min of deep hyperventilation in healthy subjects and patients with DM. Also, venous blood pH and partial pressure of O2 and CO2 were recorded before hyperventilation (HPV) and after 20min of HPV. A "hyperventilation score" was evaluated before and after HPV. When the values of DM with PNP group and control group before HPV were compared, SDTC and latency were statistically significant. Comparing the values of the excitability parameters after HPV showed statistically significant changes in the SDTC, rheobase, and refractoriness at 2.5ms in controls and DM patients without PNP. HPV resulted in no changes in SDTC in DM patients with PNP. The results of this study suggest that patients with DM and healthy subjects have different responses to HPV, and pH changes have different effects on diabetic PNP compared with healthy controls and DM patients without PNP. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The 'think test': a further technique to elicit hyperventilation.

PubMed Central

Nixon, P G; Freeman, L J

1988-01-01

Hyperventilation can undermine cardiovascular homeostasis by generating autonomic imbalance, sympathetic dominance, hypokalaemia, and intracellular alkalosis with calcium ion shifts. The role of hyperventilation in episodic disorders such as arrhythmia and coronary vasospasm can be difficult to identify if the patient does not present in an attack and so a provocation challenge is required. Today, the standard challenge is the forced hyperventilation provocation test (FHPT). A capnograph enables the resting end-tidal PCO2 to be compared with the level 3 min after the period of overbreathing. We report the use of a patient-specific challenge. After the FHPT, the subject is invited to close his eyes and think about the circumstances of an attack, feelings and sensations experienced (breathing is not mentioned) or topics that were seen to disturb the rhythm of breathing when the medical history was taken. A fall of end-tidal PCO2 of 10 mmHg or more lasting at least one minute was taken as a positive response. Out of 57 patients with cardiovascular symptoms suggesting a hypocapnic influence, resting hypocapnia (end-tidal PCO2 = 30 mmHg) was present in 3 (5%). Of the remaining 54, the FHPT was positive in 16 (30%) and the 'think test' in 33 (61%). This suggests that patient-specific stimulation has advantages over an unspecific challenge in testing for episodic hypocapnia. PMID:3133476

[Transcutaneous carbon dioxide measurements. Dynamics during hyperventilation in healthy adults].

PubMed

Bertram, L; Stiel, S; Grözinger, M

2012-12-01

In various fields of medicine the transcutaneous measurement (p(tc)CO₂) of carbon dioxide pressure (pCO₂) has been accepted as a reliable measuring method while for other disciplines the method has been doubted. Nevertheless, some minor therapeutic interventions, such as electroconvulsive therapy and breathing biofeedback used in psychiatry could benefit considerably from transcutaneous monitoring. The study presented here investigated the accuracy of transcutaneous measurement as compared to end-tidal (p(et)CO₂) and capillary (p(cap)CO₂) measurements in hyperventilation. In this study 22 healthy volunteers underwent a hyperventilation procedure with assessment of p(tc)CO₂, p(et)CO₂, p(cap)CO₂, breathing and pulse rates. The three measurement methods of pCO₂ were compared pairwise by Bland-Altman diagrams before and at the end of hyperventilation. The time delay between p(et)CO₂ and p(tc)CO₂ was determined for each individual participant by a stepwise shifting the time course of p(et)CO₂ until an optimal congruence with p(tc)CO₂ was reached. The study group consisted of 10 men and 12 women with a mean age of 30.5 ± 9.4 years. The experimental procedure lasted an average of 27.7 min including 1.9 min for the baseline measurement and 11.6 min for the actual hyperventilation procedure. The course of pCO₂ from baseline to the end of the hyperventilation phase and back to normal baseline followed a U-curve in all individuals. The pCO₂ could be reduced by a mean of approximately 45 % for the 3 measurement methods from the individual baseline of 35 mmHg. The breathing and pulse frequencies increased by 26.8 % and 17.3 %, respectively. A total of 91 p(cap)CO₂ values (mean 4 values per person) and 1,218 pairs of p(et)CO₂ and p(tc)CO₂ values (mean 55 values per person) could be evaluated. The difference of the pCO₂ values for two measurement methods revealed similar standard deviations in the Bland-Altman diagrams of about 2.5 mmHg for the 3 pairwise comparisons. The absolute measurement differences between p(et)CO₂ and p(tc)CO₂, p(cap)CO₂ and p(tc)CO₂ as well as p(et)CO₂ and p(cap)CO₂ were averaged for each single participant and afterwards across all individuals resulting in values of 2.0, 2.5 and 2.3 mmHg, respectively. When the baseline and hyperventilation periods were examined separately in this analysis they did not show any relevant differences. The individually determined delays of p(tc)CO₂ in regard to p(et)CO₂ averaged 53 s. The time delay exceeded 1 min in only two study participants. In the presented hyperventilation experiment the agreement between the p(tc)CO₂ values and the p(et)CO₂ and p(cap)CO₂ measurements were comparable to the agreement between the latter two. Altogether, the comparability of the measurement methods seemed satisfactory. The delay between the time courses of p(et)CO₂ and p(tc)CO₂ of <1 min for most participants was short and is acceptable for clinical practice. Because only healthy subjects were tested these results might not be the same in children and critically ill patients and could differ from the presented results.

Sch 37224, an experimental antiallergy compound, inhibits the neuropeptide component of hyperventilation- and nicotine-induced bronchoconstriction in guinea pigs.

PubMed

Mauser, P J; Rasquinha, C; Hey, J A; Kreutner, W; Egan, R W; Sherwood, J E; Anthes, J; Greenfeder, S; Chapman, R W

1997-01-01

Sch 37224 is an experimental antiallergy compound that inhibits hyperventilation-induced bronchoconstriction (HIB) in guinea pigs and cold air bronchospasm in human asthmatics. HIB in guinea pigs may involve the release of tachykinins such as neurokinin A (NKA) and substance P (SP), and the action of Sch 37224 in this model may relate to inhibition of these neuropeptides. We studied the effect of Sch 37224 on the neuropeptide component of HIB that was enhanced in guinea pigs treated with the neutral endopeptidase inhibitors, thiorphan and phosphoramidon. Pulmonary resistance (RL) and dynamic lung compliance (CDyn) were measured in anesthetized, mechanically ventilated guinea pigs. RL and CDyn were measured at baseline (1 ml/100 g tidal volume and 50 breaths/min) and after a 10-min period of hyperventilation (1 ml/100 g, 150 breaths/min). Hyperventilation produced modest changes in RL (+41 +/- 12%) and CDyn (-12 +/- 3%) which were markedly enhanced by treatment with 3 mg/kg of either thiorphan or phosphoramidon (RL + 269 +/- 43% for thiorphan, + 292 +/- 63% for phosphoramidon and CDyn -65 +/- 3% for thiorphan, -51 +/- 13% for phosphoramidon). In the presence of thiorphan or phosphoramidon, the bronchospasm to hyperventilation was significantly reduced (> 70%) with 5 mg/kg, p.o., of Sch 37224. In other studies, the peptidergic (conducted in the presence of ipratropium bromide and phosphoramidon) bronchoconstrictor response to intravenous nicotine (1 mg/kg) was also inhibited by Sch 37224 (0.3-10 mg/kg, p.o.). However, Sch 37224 (5 mg/kg, p.o.) had no effect on the bronchoconstrictor response to intravenous NKA. These results indicate that Sch 37224 inhibits the neuropeptide component of HIB and nicotine in guinea pigs and this effect appears to be mediated by the inhibition of the release of tachykinins from airway C fibers.

The effect of rebreathing and hyperventilation on retinal and choroidal vessels measured by spectral domain optical coherence tomography.

PubMed

Ozcimen, Muammer; Sakarya, Yasar; Goktas, Sertan; Sakarya, Rabia; Alpfidan, Ismail; Yener, Halil I; Demir, Lutfi S

2015-01-01

The purpose of this study was to examine the vasoreactivity in retina and choroid of the healthy eyes in response to experimentally altered partial arterial pressure of carbon dioxide (PaCO(2)) using a non-invasive technique, spectral domain optical coherence tomography (SD-OCT). The study included non-smoking participants between 18 and 35 years of age, having visual acuity of 20/20 and with no systemic and ocular diseases. At baseline, the participants breathed room air (normocapnia). Hypocapnia was created with the help of hyperventilation; for this, the participants were instructed to draw deep and quick breaths, resulting one breathing cycle per 2 s. To create hypercapnia subjects rebreathed from a 5 l bag at least 3 min. Choroidal thickness and retinal artery diameter were measured at baseline, and hyperventilation and rebreathing conditions by SD-OCT. Twenty eyes of 20 healthy subjects were included in this study. Their mean age was 24.90 ± 5.32 years. Hyperventilation caused a significant reduction in choroidal thickness, compared with baseline, at all points; whereas rebreathing caused no significant change at all points. The mean diameters of the arteries were 151.80 ± 7.88 μm, with a significant decline to 148.90 ± 7.25 μm at hyperventilation condition and a significant increase to 153.50 ± 7.88 μm at rebreathing condition (p = 0.018, p = 0.043, respectively). This study demonstrated that, SD-OCT was a useful tool in measuring the ocular vascular response under hypercapnia and hypocapnia conditions. These findings may be helpful for further understanding the physiological nature of ocular blood flow and this preliminary study provides a basis for future studies.

Isocapnic hyperventilation shortens washout time for sevoflurane - an experimental in vivo study.

PubMed

Hallén, K; Stenqvist, O; Ricksten, S-E; Lindgren, S

2016-10-01

Isocapnic hyperventilation (IHV) is a method that fastens weaning from inhalation anaesthesia by increasing airway concentration of carbon dioxide (CO2 ) during hyperventilation (HV). In an animal model, we evaluated a technique of adding CO2 directly to the breathing circuit of a standard anaesthesia apparatus. Eight anaesthetised pigs weighing 28 ± 2 kg were intubated and mechanically ventilated. From a baseline ventilation of 5 l/min, HV was achieved by doubling minute volume and fresh gas flow. Respiratory rate was increased from 15 to 22/min. The CO2 absorber was disconnected and CO2 was delivered (DCO2 ) to the inspiratory limb of a standard breathing circuit via a mixing box. Time required to decrease end-tidal sevoflurane concentration from 2.7% to 0.2% was defined as washout time. Respiration and haemodynamics were monitored by blood gas analysis, spirometry, electric impedance tomography and pulse contour analysis. A DCO2 of 261 ± 19 ml/min was necessary to achieve isocapnia during HV. The corresponding FICO2 -level remained stable at 3.1 ± 0.3%. During IHV, washout of sevoflurane was three times faster, 433 ± 135 s vs. 1387 ± 204 s (P < 0.001). Arterial CO2 tension and end-tidal CO2 , was 5.2 ± 0.4 kPa and 5.6 ± 0.4%, respectively, before IHV and 5.1 ± 0.3 kPa and 5.7 ± 0.3%, respectively, during IHV. In this experimental in vivo model of isocapnic hyperventilation, the washout time of sevoflurane anaesthesia was one-third compared to normal ventilation. The method for isocapnic hyperventilation described can potentially be transferred to a clinical setting with the intention to decrease emergence time from inhalation anaesthesia. © 2016 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Comparison of hyperthermic hyperventilation during passive heating and prolonged light and moderate exercise in the heat.

PubMed

Tsuji, Bun; Honda, Yasushi; Fujii, Naoto; Kondo, Narihiko; Nishiyasu, Takeshi

2012-11-01

Elevation of core temperature leads to increases in ventilation in both resting subjects and those engaged in prolonged exercise. We compared the characteristics of the hyperthermic hyperventilation elicited during passive heating at rest and during prolonged moderate and light exercise. Twelve healthy men performed three trials: a rest trial in which subjects were passively heated using hot-water immersion (41°C) and a water-perfused suit and two exercise trials in which subjects exercised at 25% (light) or 50% (moderate) of peak oxygen uptake in the heat (37°C and 50% relative humidity) after first using water immersion (18°C) to reduce resting esophageal temperature (T(es)). This protocol enabled detection of a T(es) threshold for hyperventilation during the exercise. When minute ventilation (Ve) was expressed as a function of T(es), 9 of the 12 subjects showed T(es) thresholds for hyperventilation in all trials. The T(es) thresholds for increases in Ve during light and moderate exercise (37.1 ± 0.4 and 36.9 ± 0.4°C) were both significantly lower than during rest (38.3 ± 0.6°C), but the T(es) thresholds did not differ between the two exercise intensities. The sensitivity of Ve to increasing T(es) (slope of the T(es)-Ve relation) above the threshold was significantly lower during moderate exercise (8.7 ± 3.5 l · min(-1) · °C(-1)) than during rest (32.5 ± 24.2 l · min(-1) · °C(-1)), but the sensitivity did not differ between light (10.4 ± 13.0 l · min(-1) · °C(-1)) and moderate exercise. These results suggest the core temperature threshold for hyperthermic hyperventilation and the hyperventilatory response to increasing core temperature in passively heated subjects differs from that in exercising subjects, irrespective of whether the exercise is moderate or light.

Effect of voluntary hyperventilation with supplemental CO2 on pulmonary O2 uptake and leg blood flow kinetics during moderate-intensity exercise.

PubMed

Chin, Lisa M K; Heigenhauser, George J F; Paterson, Donald H; Kowalchuk, John M

2013-12-01

Pulmonary O2 uptake (V(O₂p)) and leg blood flow (LBF) kinetics were examined at the onset of moderate-intensity exercise, during hyperventilation with and without associated hypocapnic alkalosis. Seven male subjects (25 ± 6 years old; mean ± SD) performed alternate-leg knee-extension exercise from baseline to moderate-intensity exercise (80% of estimated lactate threshold) and completed four to six repetitions for each of the following three conditions: (i) control [CON; end-tidal partial pressure of CO2 (P(ET, CO₂)) ~40 mmHg], i.e. normal breathing with normal inspired CO2 (0.03%); (ii) hypocapnia (HYPO; P(ET, CO₂) ~20 mmHg), i.e. sustained hyperventilation with normal inspired CO2 (0.03%); and (iii) normocapnia (NORMO; P(ET, CO₂) ~40 mmHg), i.e. sustained hyperventilation with elevated inspired CO2 (~5%). The V(O₂p) was measured breath by breath using mass spectrometry and a volume turbine. Femoral artery mean blood velocity was measured by Doppler ultrasound, and LBF was calculated from femoral artery diameter and mean blood velocity. Phase 2 V(O₂p) kinetics (τV(O₂p)) was different (P < 0.05) amongst all three conditions (CON, 19 ± 7 s; HYPO, 43 ± 17 s; and NORMO, 30 ± 8 s), while LBF kinetics (τLBF) was slower (P < 0.05) in HYPO (31 ± 9 s) compared with both CON (19 ± 3 s) and NORMO (20 ± 6 s). Similar to previous findings, HYPO was associated with slower V(O₂p) and LBF kinetics compared with CON. In the present study, preventing the fall in end-tidal P(CO₂) (NORMO) restored LBF kinetics, but not V(O₂p) kinetics, which remained 'slowed' relative to CON. These data suggest that the hyperventilation manoeuvre itself (i.e. independent of induced hypocapnic alkalosis) may contribute to the slower V(O₂p) kinetics observed during HYPO.

Effect of voluntary hypocapnic hyperventilation on the metabolic response during Wingate anaerobic test.

PubMed

Fujii, Naoto; Tsuchiya, Sho-Ichiro; Tsuji, Bun; Watanabe, Kazuhito; Sasaki, Yosuke; Nishiyasu, Takeshi

2015-09-01

We evaluated whether hypocapnia achieved through voluntary hyperventilation diminishes the increases in oxygen uptake elicited by short-term (e.g., ~30 s) all-out exercise without affecting exercise performance. Nine subjects performed 30-s Wingate anaerobic tests (WAnT) in control and hypocapnia trials on separate days in a counterbalanced manner. During the 20-min rest prior to the 30-s WAnT, the subjects in the hypocapnia trial performed voluntary hyperventilation (minute ventilation = 31 L min(-1)), while the subjects in the control trial continued breathing spontaneously (minute ventilation = 14 L min(-1)). The hyperventilation in the hypocapnia trial reduced end-tidal CO2 pressure from 34.8 ± 2.5 mmHg at baseline rest to 19.3 ± 1.0 mmHg immediately before the 30-s WAnT. In the control trial, end-tidal CO2 pressure at baseline rest (35.9 ± 2.5 mmHg) did not differ from that measured immediately before the 30-s WAnT (35.9 ± 3.3 mmHg). Oxygen uptake during the 30-s WAnT was lower in the hypocapnia than the control trial (1.55 ± 0.52 vs. 1.95 ± 0.44 L min(-1)), while the postexercise peak blood lactate concentration was higher in the hypocapnia than control trial (10.4 ± 1.9 vs. 9.6 ± 1.9 mmol L(-1)). In contrast, there was no difference in the 5-s peak (842 ± 111 vs. 850 ± 107 W) or mean (626 ± 74 vs. 639 ± 80 W) power achieved during the 30-s WAnT between the control and hypocapnia trials. These results suggest that during short-period all-out exercise (e.g., 30-s WAnT), hypocapnia induced by voluntary hyperventilation reduces the aerobic metabolic rate without affecting exercise performance. This implies a compensatory elevation in the anaerobic metabolic rate.

Moderate correlation between breath-holding and CO(2) inhalation/hyperventilation methods for transcranial doppler evaluation of cerebral vasoreactivity.

PubMed

Haussen, Diogo C; Katsnelson, Michael; Rodriguez, Abiezer; Campo, Nelly; Campo-Bustillo, Iszet; Romano, Jose G; Koch, Sebastian

2012-01-01

Both CO(2) inhalation followed by hyperventilation and breath-holding have been utilized to measure cerebral vasomotor reactivity (VMR) but their correlation has been poorly studied and understood. A retrospective study was conducted in 143 subjects (62.6 ± 15.8 years old, 64% men) with transcranial Doppler ultrasonography measurement of mean flow velocity (MFV) at baseline, after 30 seconds of breath-holding, and after CO(2) inhalation followed by hyperventilation, in the left and right middle cerebral artery. Breath-holding index (BHI) was calculated as the percentage of MFV increase from baseline per second of apnea. CO(2) inhalation/hyperventilation index (CO(2) /HV) was calculated as the percentage of MFV difference between CO(2) inhalation and hyperventilation. There were 75 carotid arteries with >70% stenosis or occlusion, and 18 middle cerebral arteries with >50% stenosis or occlusion. The mean BHI was 0.93 ± 0.7 and 0.89 ± 0.6, whereas the mean CO(2) /HV was 61 ± 26% and 60 ± 26%, respectively, on the right and left sides. The correlation between BHI and CO(2) /HV was moderate on the right (r = 0.33; p < 0.01) and left sides (r = 0.38; p < 0.01). Multivariate linear regression analysis indicated that age (p = 0.01) and history of stroke (p = 0.007) were associated independently with an impaired VMR on the right as measured by CO(2) /HV. No predictors for impaired VMR by CO(2) /HV on the left and by BHI on either side were found. CO(2) /HV and BHI are only moderately correlated. Further studies are necessary to determine which method more accurately predicts clinical morbidity. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound 2012; Published online in Wiley Online Library. Copyright © 2012 Wiley Periodicals, Inc.

Hyperventilation assists proarrhythmia development during delayed repolarization in clofilium-treated, anaesthetized, mechanically ventilated rabbits.

PubMed

Papp, H; Sarusi, A; Farkas, A S; Takacs, H; Kui, P; Vincze, D; Ivany, E; Varro, A; Papp, J G; Forster, T; Farkas, A

2016-10-01

Hyperventilation reduces partial pressure of CO 2 (PCO 2 ) in the blood, which results in hypokalaemia. Hypokalaemia helps the development of the life-threatening torsades de pointes type ventricular arrhythmia (TdP) evoked by repolarization delaying drugs. This implies that hyperventilation may assist the development of proarrhythmic events. Therefore, this study experimentally investigated the effect of hyperventilation on proarrhythmia development during delayed repolarization. Phenylephrine (an α 1 -adrenoceptor agonist) and clofilium (as a representative repolarization delaying agent inhibiting the rapid component of the delayed rectifier potassium current, I Kr ) were administered intravenously to pentobarbital-anaesthetized, mechanically ventilated, open chest rabbits. ECG was recorded, and the onset times and incidences of the arrhythmias were determined. Serum K + , pH and PCO 2 were measured in arterial blood samples. Clofilium prolonged the rate corrected QT interval. TdP occurred in 15 animals (TdP+ group), and did not occur in 14 animals (TdP- group). We found a strong, positive, linear correlation between serum K + and PCO 2 . There was no relationship between the occurrence of TdP and the baseline K + and PCO 2 values. However, a positive, linear correlation was found between the onset time of the first arrhythmias and the K + and PCO 2 values. The regression lines describing the relationship between PCO 2 and onset time of first arrhythmias were parallel in the TdP+ and TdP- groups, but the same PCO 2 resulted in earlier arrhythmia onset in the TdP+ group than in the TdP- group. We conclude that hyperventilation and hypocapnia with the resultant hypokalaemia assist the multifactorial process of proarrhythmia development during delayed repolarization. This implies that PCO 2 and serum K + should be controlled tightly during mechanical ventilation in experimental investigations and clinical settings when repolarization-delaying drugs are applied.

Hyperventilation in patients who have sustained myocardial infarction after a work injury.

PubMed Central

Rosen, S D; King, J C; Nixon, P G

1994-01-01

Patients who present with acute myocardial infarction after a work injury (AMI-WI) often report symptoms consistent with chronic hyperventilation which date back as far as the work injury itself, rather than to the AMI. The aim of the study was to test the hypothesis that hyperventilation significantly contributes to the symptoms of AMI-WI patients. The prevalence of hyperventilation was assessed by clinical capnography in 12 AMI-WI patients, 20 normal controls, 15 AMI patients whose AMI was conventional and not subsequent to a work injury (AMI-C) and 14 patients with post-traumatic stress disorder (PTSD). End-tidal carbon dioxide partial pressure (P(et)CO2) was measured at rest, after 1 min hyperventilation (FHPT), after recall of the relevant stressor (Think) and when the breathing was felt to be normal (MBIN). P(et)CO2 levels after FHPT were: 29.0 +/- 1.5 (mean +/- SD) mmHg for AMI-WI; 26.7 +/- 1.9 mmHg for PTSD; 32.1 +/- 4.1 mmHg for AMI-C and 33.7 +/- 1.4 mmHg for the controls (P < 0.05 and P < 0.01 for AMI-WI and PTSD, respectively, versus controls). After Think, the levels were 25.8 +/- 1.6 mmHg for AMI-WI, 24.6 +/- 1.4 mmHg for PTSD, 31.2 +/- 4.1 mmHg for AMI-C and 31.2 +/- 1.5 mmHg for normals (P < 0.05 and P < 0.01 for AMI-WI and PTSD, respectively, versus controls). For MBIN, values of P(et)CO2 were 26.8 +/- 1.7 mmHg and 26.7 +/- 1.5 mmHg for AMI-WI and PTSD versus 33.8 +/- 1.2 mmHg for normals, (P < 0.01 for both versus controls).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8207722

Respiratory physiology and pathological anxiety.

PubMed

Gorman, J M; Uy, J

1987-11-01

There has been comparatively little attention paid to the respiratory derangements in anxiety disorders. Some authorities contend, however, that indices of respiratory function may be the best objective marker of anxiety state. Furthermore, an understanding of the ventilatory status of patients with anxiety disorder has shed light on the basic pathophysiology of abnormal anxiety. For example, it is now clear that patients with a wide variety of anxiety disorders hyperventilate both chronically and acutely. Therefore, we present an explanation of the physiological changes produced by hyperventilation. In order to further study ventilatory physiology in patients with anxiety disorder, our group and others have used the carbon dioxide challenge test. The data from these experiments suggest that patients with panic disorder are hypersensitive to carbon dioxide and that carbon dioxide inhalation induces panic attacks in susceptible patients. Hyperventilation appears to be a secondary, but pathophysiologically important, event in the generation of acute panic. The implications of work in respiratory physiology for clinical management of patients with anxiety disorder are discussed.

Airway extravasation induced by increasing airway temperature in ovalbumin-sensitized rats

PubMed Central

Hsu, Chun-Chun; Tapia, Reyno J.; Lee, Lu-Yuan

2015-01-01

This study was carried out to determine whether hyperventilation of humidified warm air (HWA) induced airway extravasation in ovalbumin (Ova)-sensitized rats. Our results showed: 1) After isocapnic hyperventilation with HWA for 2 min, tracheal temperature (Ttr) was increased to 40.3°C, and the Evans blue contents in major airways and lung tissue were elevated to 651% and 707%, respectively, of that after hyperventilation with humidified room air in Ova-sensitized rats; this striking effect of HWA was absent in control rats. 2) The HWA-induced increase in Evans blue content in sensitized rats was completely prevented by a pretreatment with either L-732138, a selective antagonist of neurokinin type 1 (NK-1) receptor, or formoterol, a selective agonist of β2 adrenoceptor. This study demonstrated that an increase in airway temperature induced protein extravasation in the major airways and lung tissue of sensitized rats, and an activation of the NK-1 receptor by tachykinins released from bronchopulmonary C-fiber nerve endings was primarily responsible. PMID:25864799

Heart rate and heart rate variability in panic, social anxiety, obsessive-compulsive, and generalized anxiety disorders at baseline and in response to relaxation and hyperventilation.

PubMed

Pittig, Andre; Arch, Joanna J; Lam, Chi W R; Craske, Michelle G

2013-01-01

It remains unclear if diminished high frequency heart rate variability (HF-HRV) can be found across anxiety disorders. HF-HRV and heart rate (HR) were examined in panic (PD), generalized anxiety (GAD), social anxiety (SAD), and obsessive-compulsive disorder (OCD) relative to healthy controls at baseline and during anxiety stressors. All disorders evidenced diminished baseline HF-HRV relative to controls. Baseline HRV differences were maintained throughout relaxation. For hyperventilation, PD and GAD demonstrated greater HR than controls. Psychotropic medication did not account for HF-HRV differences except in OCD. Age and sex evidenced multiple main effects. Findings suggest that low baseline HF-HRV represents a common index for inhibitory deficits across PD, GAD, and SAD, which is consistent with the notion of autonomic inflexibility in anxiety disorders. Elevated HR responses to hyperventilation, however, are specific to PD and GAD. Copyright © 2012 Elsevier B.V. All rights reserved.

Respiratory alkalosis may impair the production of vitamin D and lead to significant morbidity, including the fibromyalgia syndrome.

PubMed

Lewis, John M; Fontrier, Toinette H; Coley, J Lynn

2017-05-01

Hyperventilation caused by physical and/or psychological stress may lead to significant respiratory alkalosis and an elevated systemic pH. The alkalotic pH may in turn suppress the normal renal release of phosphate into the urine, thereby interrupting the endogenous production of 1,25-dihydroxyvitamin D (calcitriol). This could cause a shortfall in its normal production, leading to a variety of adverse consequences. It might partially explain the pathogenesis of acute mountain sickness, a treatable disease characterized by severe hyperventilation secondary to the hypoxia of high altitude exposure. Milder degrees of hyperventilation due to different forms of stress may produce other conditions which share characteristics with acute mountain sickness. One of these may be the fibromyalgia syndrome, a chronic painful disorder for which no satisfactory treatment exists. Should fibromyalgia and acute mountain sickness have a common etiology, may they also share a common form of treatment? Evidence is presented to support this hypothesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Syncope or seizure? The diagnostic value of the EEG and hyperventilation test in transient loss of consciousness.

PubMed Central

Hoefnagels, W A; Padberg, G W; Overweg, J; Roos, R A; van Dijk, J G; Kamphuisen, H A

1991-01-01

In a prospective study of consecutive patients (age 15 or over) with transient loss of consciousness 45 patients had a history of seizure and 74 patients had a history of syncope. All patients had an EEG, ECG, laboratory tests and a hyperventilation test and were followed for an average of 14.5 months. Epileptiform activity in the interictal EEG had a sensitivity of 0.40 and a specificity of 0.95 for the diagnosis of a seizure. Epileptiform activity nearly doubled the probability of a seizure in doubtful cases. If no epileptiform activity was found, this probability remained substantially the same. The hyperventilation test had a sensitivity of 0.57 and a specificity of 0.84 for the diagnosis of syncope. A positive test increased the probability of syncope half as much in doubtful cases. A negative test did not exclude syncope. Laboratory tests were not helpful except for an ECG which was helpful in elderly patients. PMID:1800665

Eicosanoids modulate hyperpnea-induced late phase airway obstruction and hyperreactivity in dogs.

PubMed

Davis, Michael S; McCulloch, Sharron; Myers, Teresa; Freed, Arthur N

2002-01-01

A canine model of exercise-induced asthma was used to test the hypothesis that the development of a late phase response to hyperventilation depends on the acute production of pro-inflammatory mediators. Peripheral airway resistance, reactivity to hypocapnia and aerosol histamine, and bronchoalveolar lavage fluid (BALF) cell and eicosanoid content were measured in dogs approximately 5 h after dry air challenge (DAC). DAC resulted in late phase obstruction, hyperreactivity to histamine, and neutrophilic inflammation. Both cyclooxygenase and lipoxygenase inhibitors administered in separate experiments attenuated the late phase airway obstruction and hyperreactivity to histamine. Neither drug affected the late phase inflammation nor the concentrations of eicosanoids in the BALF obtained 5 h after DAC. This study confirms that hyperventilation of peripheral airways with unconditioned air causes late phase neutrophilia, airway obstruction, and hyperreactivity. The late phase changes in airway mechanics are related to the hyperventilation-induced release of both prostaglandins and leukotrienes, and appear to be independent of the late phase infiltration of inflammatory cells.

Comparison between hyperventilation and breath-holding in panic disorder: patients responsive and non-responsive to both tests.

PubMed

Nardi, Antonio E; Valença, Alexandre M; Mezzasalma, Marco A; Levy, Sandra P; Lopes, Fabiana L; Nascimento, Isabella; Freire, Rafael C; Veras, Andre B; Zin, Walter A

2006-06-15

Our aim was to compare the demographic and psychopathological features of panic disorder (PD) patients who underwent hyperventilation and breath-holding challenge tests, and to describe the features of patients who had a panic attack after both tests versus those patients who did not experience panic after either test. Eighty-five PD patients were induced to hyperventilate (30 breaths/min) for 4 min, and a week later to hold their breath for as long as possible four times with a 2-min interval in between. Anxiety scales were applied before and after the tests. Patients who responded with a panic attack to both tests (BPA, n = 25) were compared with patients who experienced spontaneous panic attacks but did not panic in response to the two tests (NPA, n = 16). The BPA group had a significantly higher presence of respiratory symptoms during a panic attack. The criteria for the respiratory PD subtype were fulfilled in 18 (72.0%) BPA patients and in 6 (37.5%) NPA patients. The BPA patients had a later onset of panic disorder and a higher familial prevalence of PD. Our data suggest that there is a distinction between PD patients who were sensitive to both hyperventilation and breath-holding tests and PD patients who were not affected by the challenge tests. The panic attack may be a final common pathway for different types of stimuli, and respiratory tests may characterize different PD subgroups.

Normalizing CO2 in chronic hyperventilation by means of a novel breathing mask: a pilot study.

PubMed

Johansen, Troels; Jack, Sandy; Dahl, Ronald

2013-10-01

Chronic idiopathic hyperventilation (CIH) is a form of dysfunctional breathing that has proven hard to treat effectively. To perform a preliminary test of the hypothesis that by periodically inducing normocapnia over several weeks, it would be possible to raise the normal resting level of CO2 and achieve a reduction of symptoms. Six CIH patients were treated 2 h a day for 4 weeks with a novel breathing mask. The mask was used to induce normocapnia in these chronically hypocapnic patients. Capillary blood gases and acid/base parameters [capillary CO2 tension (PcapCO2 ), pH, and standard base excess (SBE)] were measured at baseline and once each week at least 3 h after mask use, as well as spirometric values, breath-holding tolerance and hyperventilation symptoms as per the Nijmegen Questionnaire (NQ). The mask treatment resulted in a significant increase of resting PcapCO2 (+0.45 kPa, P = 0.028), a moderate increase in SBE (+1.4 mEq/L, P = 0.035) and a small reduction in daily symptoms (-3.8 NQ units, P = 0.046). The effect was most pronounced in the first 2 weeks of treatment. By inducing normocapnia with the breathing mask 2 h a day for 4 weeks, the normal resting CO2 and acid/base levels in chronically hyperventilating patients were partially corrected, and symptoms were reduced. © 2013 John Wiley & Sons Ltd.

Optimizing cerebral perfusion pressure during fiberoptic bronchoscopy in severe head injury: effect of hyperventilation.

PubMed

Previgliano, I J; Ripoll, P I; Chiappero, G; Galíndez, F; Germani, L; González, D H; Ferrari, N; Hlavnicka, A; Purvis, C

2002-01-01

The aim of this study was to evaluate if Hyperventilation (HV) could avoid the Intracranial Pressure (ICP) peak that occurs during Fiberoptic Bronchoscopy (FB) in severely head injured patients. A Cerebral Perfusion Pressure (CPP) > 75 mmHg was maintained in 34 patients, with a subgroup randomized to receive controlled HV during FB. Measurements were done before the procedure, during maximum ICP values and 30 minutes after FB. The HV group had minor ICP values after FB, without differences in CPP and ICP peak values.

Pulmonary O2 uptake and leg blood flow kinetics during moderate exercise are slowed by hyperventilation-induced hypocapnic alkalosis.

PubMed

Chin, Lisa M K; Heigenhauser, George J F; Paterson, Donald H; Kowalchuk, John M

2010-06-01

The effect of hyperventilation-induced hypocapnic alkalosis (Hypo) on the adjustment of pulmonary O2 uptake (VO2p) and leg femoral conduit artery ("bulk") blood flow (LBF) during moderate-intensity exercise (Mod) was examined in eight young male adults. Subjects completed four to six repetitions of alternate-leg knee-extension exercise during normal breathing [Con; end-tidal partial pressure of CO2 (PetCO2) approximately 40 mmHg] and sustained hyperventilation (Hypo; PetCO2 approximately 20 mmHg). Increases in work rate were made instantaneously from baseline (3 W) to Mod (80% estimated lactate threshold). VO2p was measured breath by breath by mass spectrometry and volume turbine, and LBF (calculated from mean femoral artery blood velocity and femoral artery diameter) was measured simultaneously by Doppler ultrasound. Concentration changes of deoxy (Delta[HHb])-, oxy (Delta[O2Hb])-, and total hemoglobin-myoglobin (Delta[HbTot]) of the vastus lateralis muscle were measured continuously by near-infrared spectroscopy (NIRS). The kinetics of VO2p, LBF, and Delta[HHb] were modeled using a monoexponential equation by nonlinear regression. The time constants for the phase 2 VO2p (Hypo, 49+/-26 s; Con, 28+/-8 s) and LBF (Hypo, 46+/-16 s; Con, 23+/-6 s) were greater (P<0.05) in Hypo compared with Con. However, the mean response time for the overall Delta[HHb] response was not different between conditions (Hypo, 23+/-5 s; Con, 24+/-3 s), whereas the Delta[HHb] amplitude was greater (P<0.05) in Hypo (8.05+/-7.47 a.u.) compared with Con (6.69+/-6.31 a.u.). Combined, these results suggest that hyperventilation-induced hypocapnic alkalosis is associated with slower convective (i.e., slowed femoral artery and microvascular blood flow) and diffusive (i.e., greater fractional O2 extraction for a given DeltaVO2p) O2 delivery, which may contribute to the hyperventilation-induced slowing of VO2p (and muscle O2 utilization) kinetics.

Pulmonary O2 uptake and leg blood flow kinetics during moderate exercise are slowed by hyperventilation-induced hypocapnic alkalosis

PubMed Central

Chin, Lisa M. K.; Heigenhauser, George J. F.; Paterson, Donald H.

2010-01-01

The effect of hyperventilation-induced hypocapnic alkalosis (Hypo) on the adjustment of pulmonary O2 uptake (V̇o2p) and leg femoral conduit artery (“bulk”) blood flow (LBF) during moderate-intensity exercise (Mod) was examined in eight young male adults. Subjects completed four to six repetitions of alternate-leg knee-extension exercise during normal breathing [Con; end-tidal partial pressure of CO2 (PetCO2) ∼40 mmHg] and sustained hyperventilation (Hypo; PetCO2 ∼20 mmHg). Increases in work rate were made instantaneously from baseline (3 W) to Mod (80% estimated lactate threshold). V̇o2p was measured breath by breath by mass spectrometry and volume turbine, and LBF (calculated from mean femoral artery blood velocity and femoral artery diameter) was measured simultaneously by Doppler ultrasound. Concentration changes of deoxy (Δ[HHb])-, oxy (Δ[O2Hb])-, and total hemoglobin-myoglobin (Δ[HbTot]) of the vastus lateralis muscle were measured continuously by near-infrared spectroscopy (NIRS). The kinetics of V̇o2p, LBF, and Δ[HHb] were modeled using a monoexponential equation by nonlinear regression. The time constants for the phase 2 V̇o2p (Hypo, 49 ± 26 s; Con, 28 ± 8 s) and LBF (Hypo, 46 ± 16 s; Con, 23 ± 6 s) were greater (P < 0.05) in Hypo compared with Con. However, the mean response time for the overall Δ[HHb] response was not different between conditions (Hypo, 23 ± 5 s; Con, 24 ± 3 s), whereas the Δ[HHb] amplitude was greater (P < 0.05) in Hypo (8.05 ± 7.47 a.u.) compared with Con (6.69 ± 6.31 a.u.). Combined, these results suggest that hyperventilation-induced hypocapnic alkalosis is associated with slower convective (i.e., slowed femoral artery and microvascular blood flow) and diffusive (i.e., greater fractional O2 extraction for a given ΔV̇o2p) O2 delivery, which may contribute to the hyperventilation-induced slowing of V̇o2p (and muscle O2 utilization) kinetics. PMID:20339012

Bronchoconstriction triggered by breathing hot humid air in patients with asthma: role of cholinergic reflex.

PubMed

Hayes, Don; Collins, Paul B; Khosravi, Mehdi; Lin, Ruei-Lung; Lee, Lu-Yuan

2012-06-01

Hyperventilation of hot humid air induces transient bronchoconstriction in patients with asthma; the underlying mechanism is not known. Recent studies showed that an increase in temperature activates vagal bronchopulmonary C-fiber sensory nerves, which upon activation can elicit reflex bronchoconstriction. This study was designed to test the hypothesis that the bronchoconstriction induced by increasing airway temperature in patients with asthma is mediated through cholinergic reflex resulting from activation of these airway sensory nerves. Specific airway resistance (SR(aw)) and pulmonary function were measured to determine the airway responses to isocapnic hyperventilation of humidified air at hot (49°C; HA) and room temperature (20-22°C; RA) for 4 minutes in six patients with mild asthma and six healthy subjects. A double-blind design was used to compare the effects between pretreatments with ipratropium bromide and placebo aerosols on the airway responses to HA challenge in these patients. SR(aw) increased by 112% immediately after hyperventilation of HA and by only 38% after RA in patients with asthma. Breathing HA, but not RA, triggered coughs in these patients. In contrast, hyperventilation of HA did not cause cough and increased SR(aw) by only 22% in healthy subjects; there was no difference between their SR(aw) responses to HA and RA challenges. More importantly, pretreatment with ipratropium completely prevented the HA-induced bronchoconstriction in patients with asthma. Bronchoconstriction induced by increasing airway temperature in patients with asthma is mediated through the cholinergic reflex pathway. The concomitant increase in cough response further indicates an involvement of airway sensory nerves, presumably the thermosensitive C-fiber afferents.

Cheyne-Stokes respiration in patients with congestive heart failure: causes and consequences.

PubMed

Lorenzi-Filho, Geraldo; Genta, Pedro R; Figueiredo, Adelaide C; Inoue, Daniel

2005-08-01

Cheyne-Stokes respiration is a form of periodic breathing in which central apneas and hypopneas alternate with periods of hyperventilation, producing a waxing and waning pattern of tidal volume. This review focuses on the causes and consequences of Cheyne-Stokes respiration in patients with congestive heart failure, in whom the prevalence is strikingly high and ranges from 30% to 50%. Several factors have been implicated in the genesis of Cheyne-Stokes respiration, including low cardiac output and recurrent hypoxia. The key pathophysiological mechanism triggering Cheyne-Stokes respiration is hyperventilation and low arterial CO2 (PaCO2) that when below the apneic threshold triggers a central apnea. Hyperventilation is associated with pulmonary congestion, and Cheyne-Stokes respiration is more prone to occur during sleep, when the respiratory system is mainly dependent on chemical control. It is associated with recurrent dips in oxygen saturation and arousals from sleep, with oscillations in blood pressure and heart rate, sympathetic activation and increased risk of ventricular tachycardia. Cheyne-Stokes respiration is an independent marker of poor prognosis and may participate in a vicious cycle, further stressing the failing heart.

Functional connectivity in raphé-pontomedullary circuits supports active suppression of breathing during hypocapnic apnea

PubMed Central

Nuding, Sarah C.; Segers, Lauren S.; Iceman, Kimberly E.; O'Connor, Russell; Dean, Jay B.; Bolser, Donald C.; Baekey, David M.; Dick, Thomas E.; Shannon, Roger; Morris, Kendall F.

2015-01-01

Hyperventilation is a common feature of disordered breathing. Apnea ensues if CO2 drive is sufficiently reduced. We tested the hypothesis that medullary raphé, ventral respiratory column (VRC), and pontine neurons have functional connectivity and persistent or evoked activities appropriate for roles in the suppression of drive and rhythm during hyperventilation and apnea. Phrenic nerve activity, arterial blood pressure, end-tidal CO2, and other parameters were monitored in 10 decerebrate, vagotomized, neuromuscularly-blocked, and artificially ventilated cats. Multielectrode arrays recorded spiking activity of 649 neurons. Loss and return of rhythmic activity during passive hyperventilation to apnea were identified with the S-transform. Diverse fluctuating activity patterns were recorded in the raphé-pontomedullary respiratory network during the transition to hypocapnic apnea. The firing rates of 160 neurons increased during apnea; the rates of 241 others decreased or stopped. VRC inspiratory neurons were usually the last to cease firing or lose rhythmic activity during the transition to apnea. Mayer wave-related oscillations (0.04–0.1 Hz) in firing rate were also disrupted during apnea. Four-hundred neurons (62%) were elements of pairs with at least one hyperventilation-responsive neuron and a correlational signature of interaction identified by cross-correlation or gravitational clustering. Our results support a model with distinct groups of chemoresponsive raphé neurons contributing to hypocapnic apnea through parallel processes that incorporate disfacilitation and active inhibition of inspiratory motor drive by expiratory neurons. During apnea, carotid chemoreceptors can evoke rhythm reemergence and an inspiratory shift in the balance of reciprocal inhibition via suppression of ongoing tonic expiratory neuron activity. PMID:26203111

Ultrasound tagged near infrared spectroscopy does not detect hyperventilation-induced reduction in cerebral blood flow.

PubMed

Lund, Anton; Secher, Niels H; Hirasawa, Ai; Ogoh, Shigehiko; Hashimoto, Takeshi; Schytz, Henrik W; Ashina, Messoud; Sørensen, Henrik

2016-01-01

Continuous non-invasive monitoring of cerebral blood flow (CBF) may be important during anaesthesia and several options are available. We evaluated the CerOx monitor that employs ultrasound tagged near infrared spectroscopy to estimate changes in a CBF index (CFI). Seven healthy males (age 21-26 years) hyperventilated and were administered phenylephrine to increase mean arterial pressure by 20-30 mmHg. Frontal lobe tissue oxygenation (ScO2) and CFI were obtained using the CerOx and mean blood flow velocity in the middle cerebral artery (MCAv mean) was determined by transcranial Doppler. Blood flow in the internal and external carotid artery (ICAf and ECAf) was determined using duplex ultrasonography and forehead skin blood flow (SkBF) and oxygenation (S skin O2) by laser Doppler and white light spectroscopy. During hyperventilation MCAv mean and ICAf decreased by 44% (median; interquartile range 40-49; p = 0.016) and 46% (40-53; p = 0.03), respectively. Conversely, CFI increased by 9% (2-31; p = 0.016), while no significant change was observed in ScO2. SkBF increased by 19% (9-53; p = 0.016) and S skin O2 by 6% (1-7; p = 0.047), although ECAf was unchanged. Administration of phenylephrine was not associated with any changes in MCAv mean, ICAf, ECAf, ScO2, SkBF, S skin O2, or CFI. The CerOx was able to detect a stable CBF during administration of phenylephrine. However, during hyperventilation MCAv mean and ICAf decreased while CFI increased, likely due to an increase in superficial tissue oxygenation. Thus, CFI does not provide an unbiased evaluation of changes in CBF.

Bronchoconstriction Triggered by Breathing Hot Humid Air in Patients with Asthma

PubMed Central

Hayes, Don; Collins, Paul B.; Khosravi, Mehdi

2012-01-01

Rationale: Hyperventilation of hot humid air induces transient bronchoconstriction in patients with asthma; the underlying mechanism is not known. Recent studies showed that an increase in temperature activates vagal bronchopulmonary C-fiber sensory nerves, which upon activation can elicit reflex bronchoconstriction. Objectives: This study was designed to test the hypothesis that the bronchoconstriction induced by increasing airway temperature in patients with asthma is mediated through cholinergic reflex resulting from activation of these airway sensory nerves. Methods: Specific airway resistance (SRaw) and pulmonary function were measured to determine the airway responses to isocapnic hyperventilation of humidified air at hot (49°C; HA) and room temperature (20–22°C; RA) for 4 minutes in six patients with mild asthma and six healthy subjects. A double-blind design was used to compare the effects between pretreatments with ipratropium bromide and placebo aerosols on the airway responses to HA challenge in these patients. Measurements and Main Results: SRaw increased by 112% immediately after hyperventilation of HA and by only 38% after RA in patients with asthma. Breathing HA, but not RA, triggered coughs in these patients. In contrast, hyperventilation of HA did not cause cough and increased SRaw by only 22% in healthy subjects; there was no difference between their SRaw responses to HA and RA challenges. More importantly, pretreatment with ipratropium completely prevented the HA-induced bronchoconstriction in patients with asthma. Conclusions: Bronchoconstriction induced by increasing airway temperature in patients with asthma is mediated through the cholinergic reflex pathway. The concomitant increase in cough response further indicates an involvement of airway sensory nerves, presumably the thermosensitive C-fiber afferents. PMID:22505744

A clinical observational study analysing the factors associated with hyperventilation during actual cardiopulmonary resuscitation in the emergency department.

PubMed

Park, Sang O; Shin, Dong Hyuk; Baek, Kwang Je; Hong, Dae Young; Kim, Eun Jung; Kim, Sang Chul; Lee, Kyeong Ryong

2013-03-01

This is the first study to identify the factors associated with hyperventilation during actual cardiopulmonary resuscitation (CPR) in the emergency department (ED). All CPR events in the ED were recorded by video from April 2011 to December 2011. The following variables were analysed using review of the recorded CPR data: ventilation rate (VR) during each minute and its associated factors including provider factors (experience, advanced cardiovascular life support (ACLS) certification), clinical factors (auscultation to confirm successful intubation, suctioning, and comments by the team leader) and time factors (time or day of CPR). Fifty-five adult CPR cases including a total of 673 min sectors were analysed. The higher rates of hyperventilation (VR>10/min) were delivered by inexperienced (53.3% versus 14.2%) or uncertified ACLS provider (52.2% versus 10.8%), during night time (61.0 versus 34.5%) or weekend CPR (53.1% versus 35.6%) and when auscultation to confirm successful intubation was performed (93.5% versus 52.8%) than not (all p<0.0001). However, experienced (25.3% versus 29.7%; p=0.448) or certified ACLS provider (20.6% versus 31.3%; p<0.0001) could not deliver high rate of proper ventilation (VR 8-10/min). Comment by the team leader was most strongly associated with the proper ventilation (odds ratio 7.035, 95% confidence interval 4.512-10.967). Hyperventilation during CPR was associated with inexperienced or uncertified ACLS provider, auscultation to confirm intubation, and night time or weekend CPR. And to deliver proper ventilation, comments by the team leader should be given regardless of providers' expert level. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Increased ventilatory variability and complexity in patients with hyperventilation disorder.

PubMed

Bokov, Plamen; Fiamma, Marie-Noëlle; Chevalier-Bidaud, Brigitte; Chenivesse, Cécile; Straus, Christian; Similowski, Thomas; Delclaux, Christophe

2016-05-15

It has been hypothesized that hyperventilation disorders could be characterized by an abnormal ventilatory control leading to enhanced variability of resting ventilation. The variability of tidal volume (VT) often depicts a nonnormal distribution that can be described by the negative slope characterizing augmented breaths formed by the relationship between the probability density distribution of VT and VT on a log-log scale. The objectives of this study were to describe the variability of resting ventilation [coefficient of variation (CV) of VT and slope], the stability in respiratory control (loop, controller and plant gains characterizing ventilatory-chemoresponsiveness interactions) and the chaotic-like dynamics (embedding dimension, Kappa values characterizing complexity) of resting ventilation in patients with a well-defined dysfunctional breathing pattern characterized by air hunger and constantly decreased PaCO2 during a cardiopulmonary exercise test. Compared with 14 healthy subjects with similar anthropometrics, 23 patients with hyperventilation were characterized by increased variability of resting tidal ventilation (CV of VT median [interquartile]: 26% [19-35] vs. 36% [28-48], P = 0.020; slope: -6.63 [-7.65; -5.36] vs. -3.88 [-5.91; -2.66], P = 0.004) that was not related to increased chemical drive (loop gain: 0.051 [0.039-0.221] vs. 0.044 [0.012-0.087], P = 0.149) but that was related to an increased ventilatory complexity (Kappa values, P < 0.05). Plant gain was decreased in patients and correlated with complexity (with Kappa 5 - degree 5: Rho = -0.48, P = 0.006). In conclusion, well-defined patients suffering from hyperventilation disorder are characterized by increased variability of their resting ventilation due to increased ventilatory complexity with stable ventilatory-chemoresponsiveness interactions. Copyright © 2016 the American Physiological Society.

Pulmonary hypertension and ventilation during exercise: Role of the pre-capillary component.

PubMed

Caravita, Sergio; Faini, Andrea; Deboeck, Gael; Bondue, Antoine; Naeije, Robert; Parati, Gianfranco; Vachiéry, Jean-Luc

2017-07-01

Excessive exercise-induced hyperventilation and high prevalence of exercise oscillatory breathing (EOB) are present in patients with post-capillary pulmonary hypertension (PH) complicating left heart disease (LHD). Patients with pre-capillary PH have even higher hyperventilation but no EOB. We sought to determine the impact of a pre-capillary component of PH on ventilatory response to exercise in patients with PH and left heart disease. We retrospectively compared patients with idiopathic or heritable pulmonary arterial hypertension (PAH, n = 29), isolated post-capillary PH (IpcPH, n = 29), and combined post- and pre-capillary PH (CpcPH, n = 12). Diastolic pressure gradient (DPG = diastolic pulmonary artery pressure - pulmonary wedge pressure) was used to distinguish IpcPH (DPG <7 mm Hg) from CpcPH (DPG ≥7 mm Hg). Pulmonary vascular resistance (PVR) was higher in PAH, intermediate in CpcPH, and low in IpcPH. All patients with CpcPH but 1 had PVR >3 Wood unit. Exercise-induced hyperventilation (high minute ventilation over carbon dioxide production, low end-tidal carbon dioxide) was marked in PAH, intermediate in CpcPH, and low in IpcPH (p < 0.001) and correlated with DPG and PVR. Prevalence of EOB decreased from IpcPH to CpcPH to PAH (p < 0.001). Patients with CpcPH may have worse hemodynamics than patients with IpcPH and distinct alterations of ventilatory control, consistent with more exercise-induced hyperventilation and less EOB. This might be explained at least in part by the presence and extent of pulmonary vascular disease. Copyright © 2017 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Central lactic acidosis, hyperventilation, and respiratory alkalosis: leading clinical features in a 3-year-old boy with malignant meningeal melanoma.

PubMed

Blüher, Susann; Schulz, Manuela; Bierbach, Uta; Meixensberger, Jürgen; Tröbs, Ralf-Bodo; Hirsch, Wolfgang; Schober, Ralf; Kiess, Wieland; Siekmeyer, Werner

2008-04-01

Meningeal tumors are extremely rare in children and are diagnostically as well as therapeutically challenging. Among the least common types of malignancies in childhood is malignant melanoma, counting for less than 1% of pediatric tumors. Due to the rarity and the wide spectrum of appearance, initial clinical features may be misleading. A 3-year-old boy was referred to our hospital with symptoms of hyperventilation, dyspnoea, tachycardia, respiratory alkalosis, inarticulate speech, and fatigue. Measurement of pH in cerebrospinal fluid (CSF) yielded central lactic acidosis despite alkalosis in peripheral blood. Diagnostic imaging procedures as well as histology and immunohistochemistry revealed the diagnosis of a malignant meningeal melanoma. We hypothesize that central lactate production of the tumor nests might have induced central acidification, thus inducing hyperventilation by stimulation of central chemoreceptors. This case is a model example of the key role of central pH as an inducer/suppressor of ventilation in humans and illustrates the critical importance of central pH for regulating both ventilation and acid-base homeostasis. Thus, pH of CSF should be measured whenever a malignant brain tumor is suspected.

CO2 reactivity and brain oxygen pressure monitoring in severe head injury.

PubMed

Carmona Suazo, J A; Maas, A I; van den Brink, W A; van Santbrink, H; Steyerberg, E W; Avezaat, C J

2000-09-01

To investigate the effect of hyperventilation on cerebral oxygenation after severe head injury. A prospective, observational study. Neurointensive care unit at a university hospital. A total of 90 patients with severe head injury (Glasgow Coma Scale score < or =8), in whom continuous monitoring of brain tissue oxygen pressure (PbrO2) was performed as a measure of cerebral oxygenation. Arterial PCO2 was decreased each day over a 5-day period for 15 mins by increasing minute volume on the ventilator setting to 20% above baseline. Arterial blood gas analysis was performed before and after changing ventilator settings. Multimodality monitoring, including PbrO2, was performed in all patients. Absolute and relative PbrO2/PaCO2 reactivity was calculated. Outcome at 6 months was evaluated according to the Glasgow Outcome Scale. Effective hyperventilation, defined by a decrease of PaCO2 > or =2 torr (0.27 kPa), was obtained in 218 (84%) of 272 tests performed. Baseline PaCO2 averaged 32.3 +/- 4.5 torr (4.31 +/- 0.60 kPa). Average reduction in PaCO2 was 3.8 +/- 1.7 torr (0.51 +/- 0.23 kPa). PbrO2 decreased by 2.8 +/- 3.7 torr (0.37 +/- 0.49 kPa; p < .001) from a baseline value of 26.5 +/- 11.6 torr (3.53 +/- 1.55 kPa). PbrO2/PaCO2 reactivity was low on day 1 (0.8 +/- 2.3 torr [0.11 +/- 0.31 kPa]), increasing on subsequent days to 6.1 +/- 4.4 torr (0.81 +/- 0.59 kPa) on day 5. PbrO2/PaCO2 reactivity on days 1 and 2 was not related to outcome. In later phases in patients with unfavorable outcome, relative reactivity was increased more markedly, reaching statistical significance on day 5. Increased hyperventilation causes a significant reduction in PbrO2, providing further evidence for possible increased risk of secondary ischemic damage during hyperventilation. The low PbrO2/PaCO2 reactivity on day 1 indicates the decreased responsiveness of cerebral microvascular vessels to PaCO2 changes, caused by generalized vascular narrowing. The increasing PbrO2/PaCO2 reactivity from days 2 to 5 suggests that the risk of compromising cerebral oxygenation by hyperventilation may increase over time.

Respiratory and psychiatric abnormalities in chronic symptomatic hyperventilation.

PubMed Central

Bass, C; Gardner, W N

1985-01-01

Many physicians believe that the hyperventilation syndrome is invariably associated with anxiety or undiagnosed organic disease such as asthma and pulmonary embolus, or both. Twenty one patients referred by specialist physicians with unexplained somatic symptoms and unequivocal chronic hypocapnia (resting end tidal Pco2 less than or equal to 4 kPa (30 mm Hg) on repeated occasions during prolonged measurement) were investigated. All but one complained of inability to take a satisfying breath. Standard lung function test results and chest radiographs were normal in all patients, but histamine challenge showed bronchial hyper-reactivity in two of 20 patients tested, and skin tests to common allergens were positive in three of 18. Ventilation-perfusion scanning was abnormal in a further three of 15 patients studied, with unmatched perfusion defects in two and isolated ventilation defects in one. None of the 21 had thyrotoxicosis, severe coronary heart disease, or other relevant cardiovascular abnormalities. Ten of the 21 patients were neurotic and suffered from chronic psychiatric disturbance characterised by anxiety, panic, and phobic symptoms. The remainder had no detectable psychiatric disorders but reported proportionately more somatic than anxiety symptoms. Severe hyperventilation can occur in the absence of formal psychiatric or detectable respiratory or other organic abnormalities. Asthma and pulmonary embolus must be specifically excluded. PMID:3922504

Blood-Injection-Injury (B-I-I) Specific Phobia Affects the Outcome of Hypoxic Challenge Testing.

PubMed

Spurling, Kristofer J; McGoldrick, Veronica P

2017-05-01

Blood-injection-injury (B-I-I) phobia is capable of producing inaccurate hypoxic challenge testing results due to anxiety-induced hyperventilation. A 69-yr-old woman with a history of hypersensitivity pneumonitis, restrictive spirometry, exercise desaturation requiring supplementary oxygen on mobilizing, reduced DLco, and B-I-I phobia was referred for hypoxic challenge testing (HCT) to assess in-flight oxygen requirements. HCT was performed by breathing a 15% FIo2 gas mixture, simulating the available oxygen in ambient air onboard aircraft pressurized to an equivalent altitude of 8000 ft. Spo2 fell to a nadir value of 81% during HCT, although it rapidly increased to 89% during the first of two attempts at blood gas sampling. A resultant blood gas sample showed an acceptable Po2 outside the criteria for recommending in-flight oxygen and a reduced Pco2. Entering the nadir Spo2 value into the Severinghaus equation gives an estimated arterial Po2 of 6 kPa (45 mmHg), which was felt to be more representative of resting values during HCT, and in-flight oxygen was recommended. While hyperventilation is an expected response to hypoxia, transient rises in Spo2 coinciding with threat of injury are likely to be attributable to emotional stress-induced hyperventilation, characteristic of B-I-I specific phobia and expected during the anticipation of exteroceptive threat, even in normal subjects. In summary, should excessive hyperventilation be detected during HCT and coincide with transient increases in Spo2, HCT should be repeated using Spo2 only as a guide to the level of hypoxemia, and Spo2 maintained using supplementary oxygen in accordance with alternative methods described in guidelines.Spurling KJ, McGoldrick VP. Blood-injection-injury (B-I-I) specific phobia affects the outcome of hypoxic challenge testing. Aerosp Med Hum Perform. 2017; 88(5):503-506.

Cerebral hemodynamic changes during sustained hypocapnia in severe head injury: can hyperventilation cause cerebral ischemia?

PubMed

Ausina, A; Báguena, M; Nadal, M; Manrique, S; Ferrer, A; Sahuquillo, J; Garnacho, A

1998-01-01

Hyperventilation (HV) is routinely used in the management of increased intracranial pressure (ICP) in severe head injury. However, this treatment continues to be controversial because it has been reported that long-lasting reduced cerebral blood flow (CBF) due to profound sustained hypocapnia may contribute to the development or deterioration of ischemic lesions. Our goal in this study was to analyze the effects of sustained hyperventilation on cerebral hemodynamics (CBF, ICP) and metabolism (arterio jugular differences of lactates = AVDL). CO2-reactivity and CBF was estimated using AVDO2 (arteriojugular differences of oxygen content). Global cerebral ischemia and increased anaerobic metabolism were considered according to AVDO2 and AVDL respectively. Thirty-three patients with severe and moderate head injury and increased ICP were included. Within 72 hours after accident, patients were hyperventilated for a period of 4 hours. During this time jugular oxygen saturation (SjO2), arterial oxygen saturation (SaO2), ICP, mean arterial blood pressure (MABP), AVDO2 and AVDL were recorded. In our study, most patients preserved CO2-reactivity (88.2%). In these cases HV was very effective in lowering ICP. Our findings showed that this reduction was due to a CBF decrease. According to basal AVDO2 twenty-five patients (75.7%) were considered as hyperemic and eight (24.2%) as not hyperemic. Global ischemia and increased anaerobic metabolism were detected in one case in the non-hyperemic group. According to AVDO2 and AVDL, no adverse effects were found during four hours of HV in hyperemic patients. Nevertheless, AVDO2 and AVDL are global measurements and might not detect regional ischemia surrounding focal lesions such as contusions and haematomas. We suggest that monitoring of AVDO2 or other haemometabolic variables should be mandatory when sustained HV is used in the management of head injury patients.

Voluntary suppression of hyperthermia-induced hyperventilation mitigates the reduction in cerebral blood flow velocity during exercise in the heat.

PubMed

Tsuji, Bun; Honda, Yasushi; Ikebe, Yusuke; Fujii, Naoto; Kondo, Narihiko; Nishiyasu, Takeshi

2015-04-15

Hyperthermia during prolonged exercise leads to hyperventilation, which can reduce arterial CO2 pressure (PaCO2 ) and, in turn, cerebral blood flow (CBF) and thermoregulatory response. We investigated 1) whether humans can voluntarily suppress hyperthermic hyperventilation during prolonged exercise and 2) the effects of voluntary breathing control on PaCO2 , CBF, sweating, and skin blood flow. Twelve male subjects performed two exercise trials at 50% of peak oxygen uptake in the heat (37°C, 50% relative humidity) for up to 60 min. Throughout the exercise, subjects breathed normally (normal-breathing trial) or they tried to control their minute ventilation (respiratory frequency was timed with a metronome, and target tidal volumes were displayed on a monitor) to the level reached after 5 min of exercise (controlled-breathing trial). Plotting ventilatory and cerebrovascular responses against esophageal temperature (Tes) showed that minute ventilation increased linearly with rising Tes during normal breathing, whereas controlled breathing attenuated the increased ventilation (increase in minute ventilation from the onset of controlled breathing: 7.4 vs. 1.6 l/min at +1.1°C Tes; P < 0.001). Normal breathing led to decreases in estimated PaCO2 and middle cerebral artery blood flow velocity (MCAV) with rising Tes, but controlled breathing attenuated those reductions (estimated PaCO2 -3.4 vs. -0.8 mmHg; MCAV -10.4 vs. -3.9 cm/s at +1.1°C Tes; P = 0.002 and 0.011, respectively). Controlled breathing had no significant effect on chest sweating or forearm vascular conductance (P = 0.67 and 0.91, respectively). Our results indicate that humans can voluntarily suppress hyperthermic hyperventilation during prolonged exercise, and this suppression mitigates changes in PaCO2 and CBF. Copyright © 2015 the American Physiological Society.

Effects of the concurrent use of a reduced dose of propofol with divided supplemental remifentanil and moderate hyperventilation on duration and morphology of electroconvulsive therapy-induced electroencephalographic seizure activity: A randomized controlled trial.

PubMed

Nishikawa, Kohki; Yamakage, Michiaki

2017-02-01

The clinical adequacy of electroconvulsive therapy (ECT) depends on not only seizure duration but also seizure amplitude and postictal suppression. The objective of this study was to evaluate the effects of combination of a reduced dose of propofol and moderate hyperventilation on seizure duration and electrical stimulus requirement for adequate ictal amplitude and postictal suppression. Prospective, randomized, controlled trial. Operating room at a municipal hospital. Sixty ASA physical status I or II patients scheduled to receive a total of >300 ECT treatments. Patients were randomly assigned to have the three interventions: the use of a standard dose (1mg/kg) of propofol and normoventilation (ETCO 2 of 40-45mmHg) (group P/N), the use of a reduced dose (0.5mg/kg) of propofol with divided remifentanil injections and normoventilation (group RP/N), and the use of a reduced dose of propofol with divided remifentanil injections and moderate hyperventilation (ETCO 2 of 30-35mmHg) (group RP/H). Patients in groups RP/N and RP/H received remifentanil 1μg/kg followed by propofol 0.5mg/kg for unconsciousness and thereafter remifentanil 1μg/kg immediately before the electrical stimulus. Patients in group RP/H had significantly longer durations of electroencephalographic (EEG) seizures in the early phase of the ECT course (P<0.05) and lower intensities of electrical stimulus in the late phase of the ECT course (P<0.05) than those in groups P/N and RP/N. A reduced dose of propofol combined with divided supplemental remifentanil under moderate hyperventilation during ECT may contribute to reduced electrical dosage due to the ability of its augmentation of seizure amplitude and postictal suppression in the late phase of the ECT course. Copyright © 2016 Elsevier Inc. All rights reserved.

Impact of hyperventilation and apnea on myocardial oxygenation in patients with obstructive sleep apnea - An oxygenation-sensitive CMR study.

PubMed

Roubille, François; Fischer, Kady; Guensch, Dominik P; Tardif, Jean-Claude; Friedrich, Matthias G

2017-02-01

Oxygenation-sensitive cardiovascular magnetic resonance imaging (OS-CMR) is an emerging technique that can monitor changes in myocardial oxygenation in vivo. Obstructive sleep apnea syndrome (OSAS) is associated with endothelial and microcirculatory dysfunction and increased cardiovascular morbidity and mortality. Little is known about myocardial responses to apnea in patients with OSAS. We hypothesized that the coronary vascular response to hyperventilation and long breath-hold is diminished in patients with OSAS when compared to healthy volunteers. Twenty-nine OSAS patients and 36 healthy volunteers were prospectively enrolled. All CMR scans were performed on a clinical 3T system. Participants performed a breathing maneuver with 60s of hyperventilation followed by a maximal breath-hold. During the breath-hold, OS-CMR images were continuously acquired and signal intensity changes were measured by a blinded reader. Patients with OSAS were older than healthy volunteers (p<0.01) and presented more co-morbidities; 66% were currently treated with nocturnal positive airway pressure. Compared to healthy participants, the expected increase of myocardial oxygenation during the first 15s of the breath-hold was significantly lower in patients with OSAS (2.6±8.3% vs. 6.7±5.6%; p<0.05), and remained reduced at all time points during the breath-hold. Importantly this result was mainly driven by patients under continuous positive airway pressure (CPAP), suggesting that CPAP might have a greater impact on increase of myocardial oxygenation rather than OSAS itself. The myocardial vascular response to combined breathing maneuvers of hyperventilation followed by voluntary apnea is blunted in patients with obstructive sleep apnea. Clinical studies should now further define the clinical role of oxygenation-sensitive CMR in patients with respiratory disorders. Copyright © 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Hyperventilation-induced nystagmus in patients with vestibular schwannoma.

PubMed

Califano, Luigi; Iorio, Giuseppina; Salafia, Francesca; Mazzone, Salvatore; Califano, Maria

2015-02-01

To determine the utility of the hyperventilation test (HVT) in the diagnosis of vestibular schwannoma (VS). A retrospective analysis of hyperventilation-induced nystagmus (HVIN) in 45 patients with unilateral VS. A tertiary referral center. Forty-five patients with VS; 30 patients with chronic vestibular neuritis; 20 healthy subjects with normal hearing and without symptoms or a history of vertigo, migraine, or neurological diseases (control group). Audiological and vestibular examination; "side-stream" measurement of end-tidal CO2 pressure (P(EtCO2)) to standardize the procedure; magnetic resonance imaging (MRI) centered on the cerebellopontine angle. An analysis of HVIN, its patterns, and its appearance threshold via the measurement of P(EtCO2) correlations with the tumor size. HVIN was observed in 40 of 45 cases (88.9%) in the schwannoma group and in 12 of 30 cases (40%) in the chronic vestibular neuritis group; HVIN was not observed in the control group (0/20 cases) (p < 0.001). In the schwannoma group, HVIN was evoked at a mean P(EtCO2) value of 16.5 ± 1.15 mm Hg. The hypofunctional labyrinth was identified with high sensibility and specificity through caloric test, head shaking test, and head thrust test. The excitatory pattern, which included HVIN with slow phases that beat toward the hypofunctional side, and the paretic pattern, which included HVIN with slow phases that beat toward the hypofunctional side, were not significantly associated with VS size (19.04 ± 10.56 mm for the excitatory pattern and 19.06 ± 11.01 mm for the paretic pattern). The difference in the VS size in HVIN+ (19.05 ± 10.60 mm) and HVIN- (8.40 ± 2.19 mm) cases was significant (p = 0.009). A 60-second hyperventilation event causes metabolic changes in the vestibular system and reveals a latent vestibular asymmetry. The presence of an excitatory pattern is the major criterion that suggests VS in patients with signs of unilateral vestibular deficit.

Voluntary suppression of hyperthermia-induced hyperventilation mitigates the reduction in cerebral blood flow velocity during exercise in the heat

PubMed Central

Tsuji, Bun; Honda, Yasushi; Ikebe, Yusuke; Fujii, Naoto; Kondo, Narihiko

2015-01-01

Hyperthermia during prolonged exercise leads to hyperventilation, which can reduce arterial CO2 pressure (PaCO2) and, in turn, cerebral blood flow (CBF) and thermoregulatory response. We investigated 1) whether humans can voluntarily suppress hyperthermic hyperventilation during prolonged exercise and 2) the effects of voluntary breathing control on PaCO2, CBF, sweating, and skin blood flow. Twelve male subjects performed two exercise trials at 50% of peak oxygen uptake in the heat (37°C, 50% relative humidity) for up to 60 min. Throughout the exercise, subjects breathed normally (normal-breathing trial) or they tried to control their minute ventilation (respiratory frequency was timed with a metronome, and target tidal volumes were displayed on a monitor) to the level reached after 5 min of exercise (controlled-breathing trial). Plotting ventilatory and cerebrovascular responses against esophageal temperature (Tes) showed that minute ventilation increased linearly with rising Tes during normal breathing, whereas controlled breathing attenuated the increased ventilation (increase in minute ventilation from the onset of controlled breathing: 7.4 vs. 1.6 l/min at +1.1°C Tes; P < 0.001). Normal breathing led to decreases in estimated PaCO2 and middle cerebral artery blood flow velocity (MCAV) with rising Tes, but controlled breathing attenuated those reductions (estimated PaCO2 −3.4 vs. −0.8 mmHg; MCAV −10.4 vs. −3.9 cm/s at +1.1°C Tes; P = 0.002 and 0.011, respectively). Controlled breathing had no significant effect on chest sweating or forearm vascular conductance (P = 0.67 and 0.91, respectively). Our results indicate that humans can voluntarily suppress hyperthermic hyperventilation during prolonged exercise, and this suppression mitigates changes in PaCO2 and CBF. PMID:25632021

Cerebral vasomotor reactivity: steady-state versus transient changes in carbon dioxide tension

PubMed Central

Brothers, R Matthew; Lucas, Rebekah A I; Zhu, Yong-Sheng; Crandall, Craig G; Zhang, Rong

2014-01-01

New Findings What is the central question of this study? The relationship between changes in cerebral blood flow and arterial carbon dioxide tension is used to assess cerebrovascular function. Hypercapnia is generally evoked by two methods, i.e. steady-state and transient increases in carbon dioxide tension. In some cases, the hypercapnia is immediately preceded by a period of hypocapnia. It is unknown whether the cerebrovascular response differs between these methods and whether a period of hypocapnia blunts the subsequent response to hypercapnia. What is the main finding and its importance? The cerebrovascular response is similar between steady-state and transient hypercapnia. However, hyperventilation-induced hypocapnia attenuates the cerebral vasodilatory responses during a subsequent period of rebreathing-induced hypercapnia. Cerebral vasomotor reactivity (CVMR) to changes in arterial carbon dioxide tension () is assessed during steady-state or transient changes in . This study tested the following two hypotheses: (i) that CVMR during steady-state changes differs from that during transient changes in ; and (ii) that CVMR during rebreathing-induced hypercapnia would be blunted when preceded by a period of hyperventilation. For each hypothesis, end-tidal carbon dioxide tension () middle cerebral artery blood velocity (CBFV), cerebrovascular conductance index (CVCI; CBFV/mean arterial pressure) and CVMR (slope of the linear regression between changes in CBFV and CVCI versus ) were assessed in eight individuals. To address the first hypothesis, measurements were made during the following two conditions (randomized): (i) steady-state increases in of 5 and 10 Torr above baseline; and (ii) rebreathing-induced transient breath-by-breath increases in . The linear regression for CBFV versus (P = 0.65) and CVCI versus (P = 0.44) was similar between methods; however, individual variability in CBFV or CVCI responses existed among subjects. To address the second hypothesis, the same measurements were made during the following two conditions (randomized): (i) immediately following a brief period of hypocapnia induced by hyperventilation for 1 min followed by rebreathing; and (ii) during rebreathing only. The slope of the linear regression for CBFV versus (P < 0.01) and CVCI versus (P < 0.01) was reduced during hyperventilation plus rebreathing relative to rebreathing only. These results indicate that cerebral vasomotor reactivity to changes in is similar regardless of the employed methodology to induce changes in and that hyperventilation-induced hypocapnia attenuates the cerebral vasodilatory responses during a subsequent period of rebreathing-induced hypercapnia. PMID:25172891

Gravity-induced hyperventilation is caused by a reduced brain perfusion.

PubMed

Arieli, R; Farhi, L E

1987-08-01

The suggestion that hyperventilation caused by increased gravity is mediated by a decrease in brain perfusion has led us to propose a mathematical model based on: (1) the CO2 balance equation for the respiratory center (RC), and (2) the relationship between RC blood flow (QRC), foot-to-head acceleration (Gz) and PRCCO2, namely, QRC = [1 - a(Gz - 1)](b X PRCCO2 + c), where the coefficients a, b and c can be calculated from data in the literature. QRC is significantly affected by + GZ only at high PaCO2. The model can be used to calculate oxygen pressure in the RC; the numbers so obtained are in good agreement with measurements of jugular vein PO2 obtained by others.

[Alkalosis].

PubMed

Kościelska, Malgorzata; Mieczkowski, Mariusz

2013-01-01

An elevation of arterial blood pH called alkalosis remains an underestimated condition in hospitalized patients. Serious alkalosis can be associated with high risk of death. The disorder can be caused by increased concentration of bicarbonate (metabolic alkalosis) or decreased concentration of carbon dioxide (respiratory alkalosis). In most cases of metabolic alkalosis it is generated by vomiting or diuretic use, whereas respiratory alkalosis is provoked by hyperventilation associated with respiratory or neurological disorder. Maintenance of metabolic alkalosis is possible only in patients with impaired renal base excretion which is most often produced by hypochloremia. In both respiratory and metabolic alkaloses treatment depends on the underlying factor. In hyperventilation syndrome is based on behavioral therapy. In most cases of metabolic alkalosis the administration of sodium and potassium chloride forms a substantial part of therapy.

40 CFR 797.1400 - Fish acute toxicity test.

Code of Federal Regulations, 2013 CFR

2013-07-01

... appearance or physiology such as discoloration, excessive mucous production, hyperventilation, opaque eyes... showing signs of stress, such as discoloration, hemorrhaging, disorientation or other unusual behavior...

40 CFR 797.1400 - Fish acute toxicity test.

Code of Federal Regulations, 2014 CFR

2014-07-01

... appearance or physiology such as discoloration, excessive mucous production, hyperventilation, opaque eyes... showing signs of stress, such as discoloration, hemorrhaging, disorientation or other unusual behavior...

40 CFR 797.1400 - Fish acute toxicity test.

Code of Federal Regulations, 2012 CFR

2012-07-01

... appearance or physiology such as discoloration, excessive mucous production, hyperventilation, opaque eyes... showing signs of stress, such as discoloration, hemorrhaging, disorientation or other unusual behavior...

Hyperventilation revisited: physiological effects and efficacy on focal seizure activation in the era of video-EEG monitoring.

PubMed

Guaranha, Mirian S B; Garzon, Eliana; Buchpiguel, Carlos A; Tazima, Sérgio; Yacubian, Elza M T; Sakamoto, Américo C

2005-01-01

Hyperventilation is an activation method that provokes physiological slowing of brain rhythms, interictal discharges, and seizures, especially in generalized idiopathic epilepsies. In this study we assessed its effectiveness in inducing focal seizures during video-EEG monitoring. We analyzed the effects of hyperventilation (HV) during video-EEG monitoring (video-EEG) of patients with medically intractable focal epilepsies. We excluded children younger than 10 years, mentally retarded patients, and individuals with frequent seizures. We analyzed 97 patients; 24 had positive seizure activation (PSA), and 73 had negative seizure activation (NSA). No differences were found between groups regarding sex, age, age at epilepsy onset, duration of epilepsy, frequency of seizures, and etiology. Temporal lobe epilepsies were significantly more activated than frontal lobe epilepsies. Spontaneous and activated seizures did not differ in terms of their clinical characteristics, and the activation did not affect the performance of ictal single-photon emission computed tomography (SPECT). HV is a safe and effective method of seizure activation during monitoring. It does not modify any of the characteristics of the seizures and allows the obtaining of valuable ictal SPECTs. This observation is clinically relevant and suggests the effectiveness and the potential of HV in shortening the presurgical evaluation, especially of temporal lobe epilepsy patients, consequently reducing its costs and increasing the number of candidates for epilepsy surgery.

Investigating hyperventilation syndrome in patients suffering from empty nose syndrome.

PubMed

Mangin, David; Bequignon, Emilie; Zerah-Lancner, Francoise; Isabey, Daniel; Louis, Bruno; Adnot, Serge; Papon, Jean-François; Coste, André; Boyer, Laurent; Devars du Mayne, Marie

2017-09-01

Patients with empty nose syndrome (ENS) following turbinate surgery often complain about breathing difficulties. We set out to determine if dyspnea in patients with ENS was associated with hyperventilation syndrome (HVS). We hypothesized that lower airway symptoms in ENS could be explained by HVS. Observational prospective study. All consecutive patients referred to our center for ENS over 1 year were invited to participate. Patients completed the Nijmegen score and underwent a hyperventilation provocation test (HVPT) and arterial blood gas and cardiopulmonary tests. HVS was defined by a delayed return of the end-tidal partial pressure of carbon dioxide in the expired gas to baseline during HVPT. Patients with HVS were asked to complete the Sinonasal Outcome Test (SNOT)-16 questionnaire before and after a specific eight-session respiratory rehabilitation program. Twenty-two of the 29 patients referred for ENS during the study period were eligible for inclusion and underwent a complete workup. HVS was diagnosed in 17 of these patients (77.3%). In the five patients who completed the SNOT-16, the score was significantly lower after rehabilitation. This study suggests that HVS is frequent in patients with ENS, and that symptoms can be improved by respiratory rehabilitation. Pathophysiological links between ENS and HVS deserve to be further explored. 2b Laryngoscope, 127:1983-1988, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Novel optoacoustic system for noninvasive continuous monitoring of cerebral venous blood oxygenation

NASA Astrophysics Data System (ADS)

Petrov, Yuriy; Petrov, Irene Y.; Prough, Donald S.; Esenaliev, Rinat O.

2012-02-01

Traumatic brain injury (TBI) and spinal cord injury are a major cause of death for individuals under 50 years of age. In the USA alone, 150,000 patients per year suffer moderate or severe TBI. Moreover, TBI is a major cause of combatrelated death. Monitoring of cerebral venous blood oxygenation is critically important for management of TBI patients because cerebral venous blood oxygenation below 50% results in death or severe neurologic complications. At present, there is no technique for noninvasive, accurate monitoring of this clinically important variable. We proposed to use optoacoustic technique for noninvasive monitoring of cerebral venous blood oxygenation by probing cerebral veins such as the superior sagittal sinus (SSS) and validated it in animal studies. In this work, we developed a novel, medical grade optoacoustic system for continuous, real-time cerebral venous blood oxygenation monitoring and tested it in human subjects at normal conditions and during hyperventilation to simulate changes that may occur in patients with TBI. We designed and built a highly-sensitive optoacoustic probe for SSS signal detection. Continuous measurements were performed in the near infrared spectral range and the SSS oxygenation absolute values were automatically calculated in real time using a special algorithm developed by our group. Continuous measurements performed at normal conditions and during hyperventilation demonstrated that hyperventilation resulted in approximately 12% decrease of cerebral venous blood oxygenation.

Inspiratory flow pattern in humans.

PubMed

Lafortuna, C L; Minetti, A E; Mognoni, P

1984-10-01

The theoretical estimation of the mechanical work of breathing during inspiration at rest is based on the common assumption that the inspiratory airflow wave is a sine function of time. Different analytical studies have pointed out that from an energetic point of view a rectangular wave is more economical than a sine wave. Visual inspection of inspiratory flow waves recorded during exercise in humans and various animals suggests that a trend toward a rectangular flow wave may be a possible systematic response of the respiratory system. To test this hypothesis, the harmonic content of inspiratory flow waves that were recorded in six healthy subjects at rest, during exercise hyperventilation, and during a maximum voluntary ventilation (MVV) maneuver were evaluated by a Fourier analysis, and the results were compared with those obtained on sinusoidal and rectangular models. The dynamic work inherent in the experimental waves and in the sine-wave model was practically the same at rest; during exercise hyperventilation and MVV, the experimental wave was approximately 16-20% more economical than the sinusoidal one. It was concluded that even though at rest the sinusoidal model is a reasonably good approximation of inspiratory flow, during exercise and MVV, a physiological controller is probably operating in humans that can select a more economical inspiratory pattern. Other peculiarities of airflow wave during hyperventilation and some optimization criteria are also discussed.

Minimizing Shortness of Breath

MedlinePlus

... and hyperventilation as well as factors like emotional stress, overexertion, habitual postures and exposure to environmental irritants. Pursed-Lip Breathing One focus of occupational therapy is to teach pursed-lip breathing. This ...

Cerebral vasomotor reactivity: steady-state versus transient changes in carbon dioxide tension.

PubMed

Brothers, R Matthew; Lucas, Rebekah A I; Zhu, Yong-Sheng; Crandall, Craig G; Zhang, Rong

2014-11-01

Cerebral vasomotor reactivity (CVMR) to changes in arterial carbon dioxide tension (P aCO 2) is assessed during steady-state or transient changes in P aCO 2. This study tested the following two hypotheses: (i) that CVMR during steady-state changes differs from that during transient changes in P aCO 2; and (ii) that CVMR during rebreathing-induced hypercapnia would be blunted when preceded by a period of hyperventilation. For each hypothesis, end-tidal carbon dioxide tension (P ET , CO 2) middle cerebral artery blood velocity (CBFV), cerebrovascular conductance index (CVCI; CBFV/mean arterial pressure) and CVMR (slope of the linear regression between changes in CBFV and CVCI versus P ET , CO 2) were assessed in eight individuals. To address the first hypothesis, measurements were made during the following two conditions (randomized): (i) steady-state increases in P ET , CO 2 of 5 and 10 Torr above baseline; and (ii) rebreathing-induced transient breath-by-breath increases in P ET , CO 2. The linear regression for CBFV versus P ET , CO 2 (P = 0.65) and CVCI versus P ET , CO 2 (P = 0.44) was similar between methods; however, individual variability in CBFV or CVCI responses existed among subjects. To address the second hypothesis, the same measurements were made during the following two conditions (randomized): (i) immediately following a brief period of hypocapnia induced by hyperventilation for 1 min followed by rebreathing; and (ii) during rebreathing only. The slope of the linear regression for CBFV versus P ET , CO 2 (P < 0.01) and CVCI versus P ET , CO 2 (P < 0.01) was reduced during hyperventilation plus rebreathing relative to rebreathing only. These results indicate that cerebral vasomotor reactivity to changes in P aCO 2 is similar regardless of the employed methodology to induce changes in P aCO 2 and that hyperventilation-induced hypocapnia attenuates the cerebral vasodilatory responses during a subsequent period of rebreathing-induced hypercapnia. © 2014 The Authors. Experimental Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

Hypocapnia and cerebral hypoperfusion in orthostatic intolerance

NASA Technical Reports Server (NTRS)

Novak, V.; Spies, J. M.; Novak, P.; McPhee, B. R.; Rummans, T. A.; Low, P. A.

1998-01-01

BACKGROUND AND PURPOSE: Orthostatic and other stresses trigger tachycardia associated with symptoms of tremulousness, shortness of breath, dizziness, blurred vision, and, often, syncope. It has been suggested that paradoxical cerebral vasoconstriction during head-up tilt might be present in patients with orthostatic intolerance. We chose to study middle cerebral artery (MCA) blood flow velocity (BFV) and cerebral vasoregulation during tilt in patients with orthostatic intolerance (OI). METHODS: Beat-to-beat BFV from the MCA, heart rate, CO2, blood pressure (BP), and respiration were measured in 30 patients with OI (25 women and 5 men; age range, 21 to 44 years; mean age, 31.3+/-1.2 years) and 17 control subjects (13 women and 4 men; age range, 20 to 41 years; mean age, 30+/-1.6 years); ages were not statistically different. These indices were monitored during supine rest and head-up tilt (HUT). We compared spontaneous breathing and hyperventilation and evaluated the effect of CO2 rebreathing in these 2 positions. RESULTS: The OI group had higher supine heart rates (P<0.001) and cardiac outputs (P<0.01) than the control group. In response to HUT, OI patients underwent a greater heart rate increment (P<0.001) and greater reductions in pulse pressure (P<0.01) and CO2 (P<0.001), but total systemic resistance failed to show an increment. Among the cerebrovascular indices, all BFVs (systolic, diastolic, and mean) decreased significantly more, and cerebrovascular resistance (CVR) was increased in OI patients (P<0.01) compared with control subjects. In both groups, hyperventilation induced mild tachycardia (P<0.001), a significant reduction of BFV, and a significant increase of CVR associated with a fall in CO2. Hyperventilation during HUT reproduced hypocapnia, BFV reduction, and tachycardia and worsened symptoms of OI; these symptoms and indices were improved within 2 minutes of CO2 rebreathing. The relationships between CO2 and BFV and heart rate were well described by linear regressions, and the slope was not different between control subjects and patients with OI. CONCLUSIONS: Cerebral vasoconstriction occurs in OI during orthostasis, which is primarily due to hyperventilation, causing significant hypocapnia. Hypocapnia and symptoms of orthostatic hypertension are reversible by CO2 rebreathing.

Hypocapnia and cerebral hypoperfusion in orthostatic intolerance.

PubMed

Novak, V; Spies, J M; Novak, P; McPhee, B R; Rummans, T A; Low, P A

1998-09-01

Orthostatic and other stresses trigger tachycardia associated with symptoms of tremulousness, shortness of breath, dizziness, blurred vision, and, often, syncope. It has been suggested that paradoxical cerebral vasoconstriction during head-up tilt might be present in patients with orthostatic intolerance. We chose to study middle cerebral artery (MCA) blood flow velocity (BFV) and cerebral vasoregulation during tilt in patients with orthostatic intolerance (OI). Beat-to-beat BFV from the MCA, heart rate, CO2, blood pressure (BP), and respiration were measured in 30 patients with OI (25 women and 5 men; age range, 21 to 44 years; mean age, 31.3+/-1.2 years) and 17 control subjects (13 women and 4 men; age range, 20 to 41 years; mean age, 30+/-1.6 years); ages were not statistically different. These indices were monitored during supine rest and head-up tilt (HUT). We compared spontaneous breathing and hyperventilation and evaluated the effect of CO2 rebreathing in these 2 positions. The OI group had higher supine heart rates (P<0.001) and cardiac outputs (P<0.01) than the control group. In response to HUT, OI patients underwent a greater heart rate increment (P<0.001) and greater reductions in pulse pressure (P<0.01) and CO2 (P<0.001), but total systemic resistance failed to show an increment. Among the cerebrovascular indices, all BFVs (systolic, diastolic, and mean) decreased significantly more, and cerebrovascular resistance (CVR) was increased in OI patients (P<0.01) compared with control subjects. In both groups, hyperventilation induced mild tachycardia (P<0.001), a significant reduction of BFV, and a significant increase of CVR associated with a fall in CO2. Hyperventilation during HUT reproduced hypocapnia, BFV reduction, and tachycardia and worsened symptoms of OI; these symptoms and indices were improved within 2 minutes of CO2 rebreathing. The relationships between CO2 and BFV and heart rate were well described by linear regressions, and the slope was not different between control subjects and patients with OI. Cerebral vasoconstriction occurs in OI during orthostasis, which is primarily due to hyperventilation, causing significant hypocapnia. Hypocapnia and symptoms of orthostatic hypertension are reversible by CO2 rebreathing.

[Correlation of brain electrical activity and motivation in healthy people].

PubMed

Bogovin, L V; Nakhamchen, D L; Kolosov, V P; Perel'man, Iu M

2014-01-01

Motivation dominates in the structure of the personality and is one of the basic notions which explains the dynamics of the behavior. The literature has little data about neurophysiology of motivation. The aim of the research was to study the correlation between the motivational sphere and electrical activity of the brain at the influence of different provocations. 24 healthy people at the age of 26-36 years were examined. The results of motivation tests turned out to be uniform (the motivation to success was of a moderate or high level, there were mean values of readiness to risk and low motivation to achievement and approval). Multiple correlations between different types of motivation and electrical activity of the brain at rest, at hyperventilation with room temperature air and at isocapnic cold air hyperventilation were revealed.

The effects of centrally injected arachidonic acid on respiratory system: Involvement of cyclooxygenase to thromboxane signaling pathway.

PubMed

Erkan, Leman Gizem; Guvenc, Gokcen; Altinbas, Burcin; Niaz, Nasir; Yalcin, Murat

2016-05-01

Arachidonic acid (AA) is a polyunsaturated fatty acid that is present in the phospholipids of the cell membranes of the body and is abundant in the brain. Exogenously administered AA has been shown to affect brain metabolism and to exhibit cardiovascular and neuroendocrine actions. However, little is known regarding its respiratory actions and/or central mechanism of its respiratory effects. Therefore, the present study was designed to investigate the possible effects of centrally injected AA on respiratory system and the mediation of the central cyclooxygenase (COX) to thromboxane A2 (TXA2) signaling pathway on AA-induced respiratory effects in anaesthetized rats. Intracerebroventricular (i.c.v.) administration of AA induced dose- and time-dependent increase in tidal volume, respiratory rates and respiratory minute ventilation and also caused an increase in partial oxygen pressure (pO2) and decrease in partial carbon dioxide pressure (pCO2) in male anaesthetized Spraque Dawley rats. I.c.v. pretreatment with ibuprofen, a non-selective COX inhibitor, completely blocked the hyperventilation and blood gases changes induced by AA. In addition, central pretreatment with different doses of furegrelate, a TXA2 synthesis inhibitor, also partially prevented AA-evoked hyperventilation and blood gases effects. These data explicitly show that centrally administered AA induces hyperventilation with increasing pO2 and decreasing pCO2 levels which are mediated by the activation of central COX to TXA2 signaling pathway. Copyright © 2016 Elsevier B.V. All rights reserved.

Fibromyalgia as a cause of uncontrolled asthma: a case-control multicenter study.

PubMed

Martinez-Moragon, Eva; Plaza, Vicente; Torres, Isabel; Rosado, Ana; Urrutia, Isabel; Casas, Xavier; Hinojosa, Belen; Blanco-Aparicio, Marina; Delgado, Julio; Quirce, Santiago; Sabadell, Carles; Cebollero, Pilar; Muñoz-Fernández, Ana

2017-12-01

Fibromyalgia can affect the control of asthma when both diseases are present in a single patient. To characterize asthma in patients with concomitant fibromyalgia to assess whether fibromyalgia is an independent factor of asthma severity that influences poor asthma control. We also evaluated how dyspnea is perceived by patients in order to demonstrate that alterations in the perception of airway obstruction may be responsible for poor asthma control. This was a cross-sectional case-control multicenter study, in which 56 patients in the asthma and fibromyalgia group were matched to 36 asthmatics by sex, approximate age, and asthma severity level. All patients were women. Study variables included the Asthma Control Test (ACT), the Mini Asthma Quality of Life Questionnaire (MiniAQLQ), the Nijmegen hyperventilation syndrome questionnaire, the Hospital Anxiety and Depression Scale, and perception of dyspnea after acute bronchoconstriction. Although patients in both study groups showed similar asthma severity and use of anti-asthmatic drugs, patients in the asthma and fibromyalgia group showed lower scores on the ACT and MiniAQLQ questionnaires, and higher scores of anxiety and depression as well as hyperventilation compared to asthma patients without fibromyalgia. All these differences were statistically significant. Fibromyalgia in patients with asthma influences poor control of the respiratory disease and is associated with altered perception of dyspnea, hyperventilation syndrome, high prevalence of depression and anxiety, and impaired quality of life. Fibromyalgia may be considered a risk factor for uncontrolled asthma in patients suffering from asthma and fibromyalgia concomitantly.

Widespread cardiovascular autonomic dysfunction in primary amyloidosis: does spontaneous hyperventilation have a compensatory role against postural hypotension?

PubMed Central

Bernardi, L; Passino, C; Porta, C; Anesi, E; Palladini, G; Merlini, G

2002-01-01

Objective: To investigate the possible causes of abnormal blood pressure control in light chain related (primary, AL) amyloidosis. Design: Cardiovascular, autonomic, and respiratory response to passive tilting were investigated in 51 patients with primary amyloidosis (mean (SEM) age 56 (2) years) and in 20 age matched controls. Spontaneous fluctuations in RR interval, respiration, end tidal carbon dioxide, blood pressure, and skin microcirculation were recorded during supine rest and with tilting. The values were subjected to spectral analysis to assess baroreflex sensitivity and the autonomic modulation of cardiac and vascular responses. Setting: Tertiary referral centre. Results: Autonomic modulation of the heart and blood pressure was nearly absent in the patients with amyloidosis: thus baroreflex sensitivity and the low frequency (0.1 Hz) fluctuations in all cardiovascular signals were severely reduced (p < 0.01 or more), as were respiratory fluctuations in the RR interval, and no change was observed upon tilting. Despite reduced autonomic modulation, blood pressure remained relatively stable in the amyloid group from supine to tilting. End tidal carbon dioxide was reduced in the amyloid patients (p < 0.001) indicating persistent hyperventilation; the breathing rate correlated inversely with the fall in blood pressure on tilting (p < 0.05). Conclusions: In primary amyloidosis, pronounced abnormalities in arterial baroreflexes and cardiovascular autonomic modulation to the heart and the vessels may be partly compensated for by hyperventilation at a slow breathing rate. PMID:12433892

Cardiopulmonary and arterial baroreceptor unloading during passive hyperthermia does not contribute to hyperthermia-induced hyperventilation.

PubMed

Lucas, Rebekah A I; Pearson, James; Schlader, Zachary J; Crandall, Craig G

2015-11-01

What is the central question of this study? Does baroreceptor unloading during passive hyperthermia contribute to increases in ventilation and decreases in end-tidal carbon dioxide during that exposure? What is the main finding and its importance? Hyperthermic hyperventilation is not mitigated by expanding central blood volume and reloading the cardiopulmonary baroreceptors via rapid saline infusion or by reloading the arterial baroreceptors via phenylephrine administration. The absence of a reduction in ventilation upon reloading the baroreceptors to pre-hyperthermic levels indicates that cardiopulmonary and arterial baroreceptor unloading with hyperthermia is unlikely to contribute to hyperthermic hyperventilation in humans. This study tested the hypothesis that baroreceptor unloading during passive hyperthermia contributes to increases in ventilation and decreases in end-tidal partial pressure of carbon dioxide (P ET ,CO2) during that exposure. Two protocols were performed, in which healthy subjects underwent passive hyperthermia (increasing intestinal temperature by ∼1.8°C) to cause a sustained increase in ventilation and reduction in P ET ,CO2. Upon attaining hyperthermic hyperventilation, in protocol 1 (n = 10; three females) a bolus (19 ± 2 ml kg(-1) ) of warm (∼38°C) isotonic saline was rapidly (5-10 min) infused intravenously to restore reductions in central venous pressure, whereas in protocol 2 (n = 11; five females) phenylephrine was infused intravenously (60-120 μg min(-1) ) to return mean arterial pressure to normothermic levels. In protocol 1, hyperthermia increased ventilation (by 2.2 ± 1.7 l min(-1) , P < 0.01), while reducing P ET ,CO2 (by 4 ± 3 mmHg, P = 0.04) and central venous pressure (by 5 ± 1 mmHg, P <0.01). Saline infusion increased central venous pressure by 5 ± 1 mmHg (P < 0.01), restoring it to normothermic values, but did not change ventilation or P ET ,CO2 (P > 0.05). In protocol 2, hyperthermia increased ventilation (by 5.0 ± 2.7 l min(-1) , P <0.01) and reduced P ET ,CO2 (by 5 ± 2 mmHg, P < 0.01) and mean arterial pressure (by 9 ± 7 mmHg, P <0.01). Phenylephrine infusion increased mean arterial pressure by 12 ± 3 mmHg (P < 0.01), restoring it to normothermic values, but did not change ventilation or P ET ,CO2 (P > 0.05). The absence of a reduction in ventilation upon reloading the cardiopulmonary and arterial baroreceptors to pre-hyperthermic levels indicates that baroreceptor unloading with hyperthermia is unlikely to contribute to hyperthermic hyperventilation in humans. © 2015 The Authors. Experimental Physiology © 2015 The Physiological Society.

Dynamic contrast-enhanced x-ray CT measurement of cerebral blood volume in a rabbit tumor model

NASA Astrophysics Data System (ADS)

Cenic, Aleksa; Lee, Ting-Yim; Craen, Rosemary A.; Gelb, Adrian W.

1998-07-01

Cerebral blood volume (CBV) is a major determinant of intracranial pressure (ICP). Hyperventilation is commonly employed to reduce raised ICP (e.g. in brain tumour patients) presumably through its effect on CBV. With the advent of slip- ring CT scanners, dynamic contrast-enhanced imaging allows for the measurement of CBV with high spatial resolution. Using a two-compartment model to characterize the distribution of X- ray contrast agent in the brain, we have developed a non- equilibrium CT method to measure CBV in normal and pathological regions. We used our method to investigate the effect of hyperventilation on CBV during propofol anaesthesia in rabbits with implanted brain tumours. Eight New Zealand White rabbits with implanted VX2 carcinoma brain tumours were studied. For each rabbit, regional CBV measurements were initially made at normocapnia (PaCO2 40 mmHg) and then at hyperventilation (PaCO2 25 mmHg) during propofol anaesthesia. The head was positioned such that a coronal image through the brain incorporated a significant cross-section of the brain tumour as well as a radial artery in a forelimb. Images at the rate of 1 per second were acquired for 2 minutes as Omnipaque 300 (1.5 ml/kg rabbit weight) was injected via a peripheral vein. In these CT images, regions of interest in the brain tissue (e.g. tumour, contra-lateral normal, and peri-tumoural) and the radial artery were drawn. For each region, the mean CT number in pre-contrast images was subtracted from the mean CT number in post-contrast images to produce either the tissue contrast concentration curve, or the arterial contrast concentration curve. Using our non- equilibrium analysis method based on a two-compartment model, regional CBV values were determined from the measured contrast concentration curves. From our study, the mean CBV values [+/- SD] in the tumour, peri-tumoural, and contra-lateral normal regions during normocapnia were: 5.47 plus or minus 1.97, 3.28 plus or minus 1.01, and 1.86 plus or minus 0.54 ml/100 g, respectively. Following hyperventilation, we found a significant decrease (p less than 0.025) of 10.4% in CBV in the peri-tumoural region, and no statistically significant change in CBV in the tumour or contra-lateral normal regions. We have developed a convenient method for measuring CBV in normal and pathological tissue using a slip-ring CT scanner. In a brain tumour model, we found that CBV was markedly increased in tumour and peri-tumoural regions compared to normal regions. Our results suggest that the reduction of raised ICP following hyperventilation during propofol anaesthesia may be mainly due to a reduction in CBV in the peri-tumoural tissue rather than in the bulk of the tumour or normal regions. Our method has the potential to provide further knowledge on the cerebral hemodynamics of space- occupying lesions during different anaesthetic interventions or treatment regiments.

A Laboratory-Based Test of the Relation between Adolescent Alcohol Use and Panic-Relevant Responding

PubMed Central

Blumenthal, Heidemarie; Cloutier, Renee M.; Zamboanga, Byron L.; Bunaciu, Liviu; Knapp, Ashley A.

2015-01-01

A burgeoning literature supports a link between alcohol use and panic-spectrum problems (e.g., panic attacks, disorder) among adolescents, but the direction of influence has yet to be properly examined. From a theoretical perspective, panic-spectrum problems may increase risk for problematic drinking via affect regulation efforts (e.g., self-medication), and problematic consumption also may increase or initiate panic-relevant responding (e.g., learning or kindling models). The objective of the current investigation was to examine the role of prior alcohol use in predicting panic-relevant responding, as well as panic symptom history in predicting the desire to consume alcohol, in the context of either a voluntary hyperventilation or a low-arousal task. Participants were community-recruited adolescents aged 12-17 years (n = 92, Mage = 15.42, SD = 1.51; 39.1% girls). Results indicated that prior alcohol use predicted panic-relevant responding among those undergoing the hyperventilation task (but not the low-arousal task), and that this finding was robust to the inclusion of theoretically-relevant covariates (i.e. age, sex, negative affectivity). However, panic symptom history did not predict the desire to consume alcohol as a function of either the hyperventilation or low-arousal condition. This work sheds further light on the nature of the relation between panic-spectrum problems and problematic alcohol use in adolescence. Specifically, the current findings suggest that frequent alcohol use may increase panic vulnerability among adolescents, whereas acute panic symptoms may not elicit the immediate (self-reported) desire to drink. PMID:26053320

Effects of hyperthermia on ventilation and metabolism during hypoxia in conscious mice.

PubMed

Iwase, Michiko; Izumizaki, Masahiko; Kanamaru, Mitsuko; Homma, Ikuo

2004-02-01

Hyperthermia and hypoxia influence ventilation and metabolism; however, their synergistic effects remain unanswered. We hypothesized that an enhancement of ventilation induced by hyperthermia is competitive with hypoxic hypometabolism. We then examined the relationship of body temperature, hypoxia, and respiration in conscious mice, measuring minute ventilation (VE), aerobic metabolism, and arterial blood gases. All parameters were measured at two different body temperatures (BTs), approximately 37 degrees C (normothermia) and 39 degrees C (hyperthermia), under both normoxia (room air inhalation) and hypoxia (7% O2 inhalation). Under normoxia, VE and O2 consumption (VO2) were lower at hyperthermia than at normothermia, and the VE-VO2 ratio remained constant. PaCO2 values were normal at both BTs under normoxia. Hypoxic gas inhalation increased VE, which reached a peak in 2 min, then decreased at both BTs. VE remained at a higher level during hyperthermia than during normothermia throughout the 10 min experiment. VO2 decreased during hypoxia at both BTs. Hypoxia increased the VE-VO2 ratio because of relatively high VE with respect to the decreased VO2, which means hyperventilation. At hypoxia under hyperthermia, serious hyperventilation occurred with a further increase in VE. The augmented ventilation may be due to the thermal stimulus and a lowered thermoregulatory set point for hypoxia. Thus hyperthermia reduces ventilation and metabolism to maintain normocapnia; as a result, thermogenesis is reduced under normoxia. Hyperthermia augments hyperventilation induced by hypoxia, leading to severe hypoxic hypocapnia. Thermal stimuli may impair the adjustment of ventilation and metabolism when O2 is limited.

Alcohol Use History and Panic-Relevant Responding among Adolescents: A Test using a Voluntary Hyperventilation Challenge

PubMed Central

Blumenthal, Heidemarie; Leen-Feldner, Ellen W.; Knapp, Ashley A.; Bunaciu, Liviu; Zamboanga, Byron L.

2012-01-01

Given the onset of alcohol use, neurological sensitivity, and enhanced panic-relevant vulnerability, adolescence is a key period in which to study the documented linkage between alcohol and panic-related problems. The current study was designed to build upon and uniquely extend extant work via (1) utilization of well-established experimental psychopathology techniques, and (2) evaluation of unique associations between alcohol use and panic symptoms after controlling for theoretically-relevant behavioral, environmental, and individual difference variables (i.e., age, gender, negative affectivity, anxiety sensitivity, child and parent tobacco use, and parental panic disorder). Participants were 111 community-recruited adolescents ages 12–17 years (M = 15.76 years; n = 50 girls). Youth completed a battery of well-established questionnaires and a voluntary hyperventilation challenge, and parents present at the laboratory completed a structured clinical interview. Adolescent alcohol use was categorized as Non-Users, Experimenters, or Users. Panic symptoms were indexed via retrospective self-report and adolescents’ response to a biological challenge procedure (i.e., voluntary hyperventilation). After controlling for theoretically-relevant covariates, Users evidenced elevated panic-relevant symptoms and responding compared to Non-Users; Experimenters did not differ from Non-Users. Findings suggest alcohol use history is uniquely associated with panic symptomatology among youth, including “real-time” reactivity elicited by a laboratory challenge. While there is significant work yet to be done, these data advance extant work and lay the groundwork for the types of sophisticated designs that will be needed to answer the most pressing and complex questions regarding the link between alcohol use and panic symptoms among adolescents. PMID:22369219

Hyperventilation-induced hypocapnic alkalosis slows the adaptation of pulmonary O2 uptake during the transition to moderate-intensity exercise.

PubMed

Chin, Lisa M K; Leigh, Ryan J; Heigenhauser, George J F; Rossiter, Harry B; Paterson, Donald H; Kowalchuk, John M

2007-08-15

The effect of voluntary hyperventilation-induced hypocapnic alkalosis (RALK) on pulmonary O2 uptake (VO2) kinetics and muscle deoxygenation was examined in young male adults (n=8) during moderate-intensity exercise. Subjects performed five repetitions of a step-transition in work rate from 20 W cycling to a work rate corresponding to 90% of the estimated lactate threshold during control (CON; PET,CO2, approximately 40 mmHg) and during hyperventilation (RALK; PET,CO2, approximately 20 mmHg). was measured breath-by-breath and relative concentration changes in muscle deoxy- (DeltaHHb), oxy- (DeltaO2Hb) and total (DeltaHbtot) haemoglobin were measured continuously using near-infrared (NIR) spectroscopy (Hamamatsu, NIRO 300). The time constant for the fundamental, phase 2, VO2 response (tau VO2) was greater (P<0.05) in RALK (48+/-11 s) than CON (31+/-9 s), while tauHHb was similar between conditions (RALK, 12+/-4 s; CON, 11+/-4 s). The DeltaHb(tot) was lower (P<0.05) in RALK than CON, prior to (RALK, -3+/-5 micromol l(-1); CON, -1+/-4 micromol l(-1)) and at the end (RALK, 1+/-6 micromol l(-1); CON, 5+/-5 micromol l(-1)) of moderate-intensity exercise. Although slower adaptation of during RALK may be related to an attenuated activation of PDH (and other enzymes) and provision of oxidizable substrate to the mitochondria (i.e. metabolic inertia), the present findings also suggest a role for a reduction in local muscle perfusion and O2 delivery.

Respiratory alkalosis and associated electrolytes in long-term ventilator dependent persons with tetraplegia.

PubMed

Watt, J W; Silva, P

2001-11-01

A pilot case control study of the acid-base and electrolyte status in 30 long-term ventilator-dependent (LTVD) and 30 self ventilating persons with tetraplegia. To assess the extent of respiratory alkalosis and screen for associated hypokalaemia, hypomagnesaemia and/or hypophosphataemia. Medically stable persons with tetraplegia under the long-term care of the Southport Spinal Injuries Centre, England. Blood gases and electrolytes were sampled from 30 control patients with tetraplegia and from 30 patients having been LTVD for more than 12 months. All the blood gas measurements in the LTVD group lay outside both the reference range and the 95% confidence intervals (CI) of the control group: pH 7.46 (0.06); PCO(2) 3.46 (1.1) kPa; bicarbonate 18.3 (3.8) and base excess -3.2 (2.8) mmol/l; PO(2) 13.8 (2.8) kPa (means and standard deviations). The serum potassium, magnesium, phosphate, and sodium means lay within the reference ranges but the potassium, phosphate and calcium were at or below the 95% CI of the control values. One patient on part-time ventilatory support having less bicarbonate compensation had low serum electrolytes during ventilation. There was no evidence of biochemical jeopardy from long-term mechanical hyperventilation although acutely administered hyperventilation has the potential to cause falls in serum potassium, magnesium and phosphate and so caution should be exercised in part-time ventilated persons. The full range of electrolytes should be assayed during stabilisation in LTVD and periodically thereafter. Hyperventilation helps to maintain good oxygenation in LTVD persons with paralysis and normal lungs. None.

Cerebral venous blood oxygenation monitoring during hyperventilation in healthy volunteers with a novel optoacoustic system

NASA Astrophysics Data System (ADS)

Petrov, Andrey; Prough, Donald S.; Petrov, Irene Y.; Petrov, Yuriy; Deyo, Donald J.; Henkel, Sheryl N.; Seeton, Roger; Esenaliev, Rinat O.

2013-03-01

Monitoring of cerebral venous oxygenation is useful to facilitate management of patients with severe or moderate traumatic brain injury (TBI). Prompt recognition of low cerebral venous oxygenation is a key to avoiding secondary brain injury associated with brain hypoxia. In specialized clinical research centers, jugular venous bulb catheters have been used for cerebral venous oxygenation monitoring and have demonstrated that oxygen saturation < 50% (normal range is 55-75%) correlates with poor clinical outcome. We developed an optoacoustic technique for noninvasive monitoring of cerebral venous oxygenation. Recently, we designed and built a novel, medical grade optoacoustic system operating in the near-infrared spectral range for continuous, real-time oxygenation monitoring in the superior sagittal sinus (SSS), a large central cerebral vein. In this work, we designed and built a novel SSS optoacoustic probe and developed a new algorithm for SSS oxygenation measurement. The SSS signals were measured in healthy volunteers during voluntary hyperventilation, which induced changes in SSS oxygenation. Simultaneously, we measured exhaled carbon dioxide concentration (EtCO2) using capnography. Good temporal correlation between decreases in optoacoustically measured SSS oxygenation and decreases in EtCO2 was obtained. Decreases in EtCO2 from normal values (35-45 mmHg) to 20-25 mmHg resulted in SSS oxygenation decreases by 3-10%. Intersubject variability of the responses may relate to nonspecific brain activation associated with voluntary hyperventilation. The obtained data demonstrate the capability of the optoacoustic system to detect in real time minor changes in the SSS blood oxygenation.

Feasibility to apply eucapnic voluntary hyperventilation in young elite athletes.

PubMed

Van der Eycken, S; Schelpe, A; Marijsse, G; Dilissen, E; Troosters, T; Vanbelle, V; Aertgeerts, S; Dupont, L J; Peers, K; Bullens, D M; Seys, S F

2016-02-01

Exercise-induced bronchoconstriction (EIB) is more common in athletes compared to the general population. The eucapnic voluntary hyperventilation test is used to detect EIB in adult athletes. It is however unclear whether this technique is also applicable to young athletes. Young athletes (basketball (n = 13), football (n = 19), swimming (n = 12)) were recruited at the start of their elite sports career (12-14 years). Eight age-matched controls were also recruited. Eucapnic voluntary hyperventilation test was performed according to ATS guidelines in all subjects. A second (after 1 year, n = 32) and third (after 2 years, n = 39) measurement was performed in a subgroup of athletes and controls. At time of first evaluation, 3/13 basketball players, 4/19 football players, 5/11 swimmers and 1/8 controls met criteria for EIB (fall in FEV1≥10% after EVH). A ventilation rate of >85% of the maximal voluntary ventilation (MVV) is recommended by current guidelines (for adults) but was only achieved by a low number of individuals (first occasion: 27%, third occasion: 45%) However, MVV in young athletes corresponds to 30 times FEV1, which is equivalent to 85% of MVV in adults. A threshold of 70% of MVV (21 times FEV1) is feasible in the majority of young athletes. EIB is present in a substantial number of individuals at the age of 12-14 years, especially in swimmers. This underscores the importance of screening for EIB at this age. EVH is feasible in young elite athletes, however target ventilation needs to be adjusted accordingly. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mimickers of generalized spike and wave discharges.

PubMed

Azzam, Raed; Bhatt, Amar B

2014-06-01

Overinterpretation of benign EEG variants is a common problem that can lead to the misdiagnosis of epilepsy. We review four normal patterns that mimic generalized spike and wave discharges: phantom spike-and-wave, hyperventilation hypersynchrony, hypnagogic/ hypnopompic hypersynchrony, and mitten patterns.

Millivolt-scale DC shifts in the human scalp EEG: evidence for a nonneuronal generator.

PubMed

Voipio, Juha; Tallgren, Pekka; Heinonen, Erkki; Vanhatalo, Sampsa; Kaila, Kai

2003-04-01

Slow shifts in the human scalp-recorded EEG, including those related to changes in brain CO(2) levels, have been generally assumed to result from changes in the level of tonic excitation of apical dendrites of cortical pyramidal neurons. We readdressed this issue using DC-EEG shifts elicited in healthy adult subjects by hypo- or hypercapnia. A 3-min period of hyperventilation resulted in a prompt negative shift with a rate of up to 10 microV/s at the vertex (Cz) and an extremely steep dependence (up to 100 microV/mmHg) on the end-tidal Pco(2). This shift had a maximum of up to -2 mV at Cz versus the temporal derivations (T3/T4). Hyperventilation-like breathing of 5% CO(2)-95% O(2), which does not lead to a significant hypocapnia, resulted in a near-complete block of the negative DC shift at Cz. Hypoventilation, or breathing 5% CO(2) in air at normal respiratory rate, induced a positive shift. The high amplitude of the voltage gradients on the scalp induced by hyperventilation is not consistent with a neuronal origin. Instead, the present data suggest that they are generated by extracortical volume currents driven by a Pco(2)-dependent potential difference across epithelia separating the cerebrospinal fluid and blood. Since changes in respiratory patterns and, hence, in the level of brain Pco(2), are likely to occur under a number of experimental conditions in which slow EEG responses have been reported (e.g., attention shifts, preparatory states, epileptic seizures, and hypoxic episodes), the present results call for a thorough reexamination of the mechanisms underlying scalp-recorded DC-EEG responses.

End-tidal pCO2 in blood phobics during viewing of emotion- and disease-related films.

PubMed

Ritz, Thomas; Wilhelm, Frank H; Gerlach, Alexander L; Kullowatz, Antje; Roth, Walton T

2005-01-01

Many patients with blood, injection, and injury (BII) phobia respond to specific stimuli with vasovagal dysregulation and fainting. However, little is known about the role of hyperventilation in the distress of these patients. Hyperventilation, defined by subnormal arterial pCO2 levels, induces anxiety and may promote the development of fainting. We studied end-tidal pCO2 in 12 patients with BII phobia and 14 nonanxious controls during presentation of emotional films. Ten film clips were shown, two in each of 5 categories: pleasant, unpleasant, neutral, BII-related (surgery), and asthma-related (portraying labored breathing). For each subject, two subsets were created, each containing one clip from each category. For one subset, the instruction was simply to view the film, and for the other subset, to view the film while tensing the leg muscles. PCO2, heart rate, blood pressure, and leg electromyogram were recorded continuously during viewing, and self-report of symptoms and emotion was collected after each film. Patients reported the greatest anxiety and disgust during surgery films. PCO2 was relatively stable throughout all categories except surgery films, during which minima were below 30 mm Hg, indicating significant hypocapnia. Cardiovascular variables suggested biphasic patterns in two patients with BII phobia. These patients, together with one additional patient and one control who were close to fainting after or during one surgery film, also showed a marked fall in pCO2) Leg muscle tension raised heart rate and systolic blood pressure for all films, but was not related to near-fainting or endurance in surgery film viewing. Hyperventilation is part of the fear response of patients with BII phobia, but was transitory in experimental fear induction using surgery films. Its role in real-life exposure and fainting deserves further study.

Hyperventilation-induced hypocapnic alkalosis slows the adaptation of pulmonary O2 uptake during the transition to moderate-intensity exercise

PubMed Central

Chin, Lisa M K; Leigh, Ryan J; Heigenhauser, George J F; Rossiter, Harry B; Paterson, Donald H; Kowalchuk, John M

2007-01-01

The effect of voluntary hyperventilation-induced hypocapnic alkalosis (RALK) on pulmonary O2 uptake (V˙o2) kinetics and muscle deoxygenation was examined in young male adults (n = 8) during moderate-intensity exercise. Subjects performed five repetitions of a step-transition in work rate from 20 W cycling to a work rate corresponding to 90% of the estimated lactate threshold during control (CON; , ∼40 mmHg) and during hyperventilation (RALK; , ∼20 mmHg). V˙o2 was measured breath-by-breath and relative concentration changes in muscle deoxy- (ΔHHb), oxy- (ΔO2Hb) and total (ΔHbtot) haemoglobin were measured continuously using near-infrared (NIR) spectroscopy (Hamamatsu, NIRO 300). The time constant for the fundamental, phase 2, V˙o2 response (τV˙o2) was greater (P < 0.05) in RALK (48 ± 11 s) than CON (31 ± 9 s), while τHHb was similar between conditions (RALK, 12 ± 4 s; CON, 11 ± 4 s). The ΔHbtot was lower (P < 0.05) in RALK than CON, prior to (RALK, −3 ± 5 μmol l−1; CON, −1 ± 4 μmol l−1) and at the end (RALK, 1 ± 6 μmol l−1; CON, 5 ± 5 μmol l−1) of moderate-intensity exercise. Although slower adaptation of V˙o2 during RALK may be related to an attenuated activation of PDH (and other enzymes) and provision of oxidizable substrate to the mitochondria (i.e. metabolic inertia), the present findings also suggest a role for a reduction in local muscle perfusion and O2 delivery. PMID:17584832

Rescue of hyperexcitability in hippocampal CA1 neurons from Mecp2 (-/y) mouse through surface potential neutralization

PubMed Central

Mironov, Sergej L.

2018-01-01

Hyperventilation is a known feature of Rett syndrome (RTT). However, how hyperventilation is related to other RTT symptoms such as hyperexcitability is unknown. Intense breathing during hyperventilation induces hypocapnia and culminates in respiratory alkalosis. Alkalinization of extracellular milieu can trigger epilepsy in patients who already have neuronal hyperexcitability. By combining patch-clamp electrophysiology and quantitative glutamate imaging, we compared excitability of CA1 neurons of WT and Mecp2 (-/y) mice, and analyzed the biophysical properties of subthreshold membrane channels. The results show that Mecp2 (-/y) CA1 neurons are hyperexcitable in normal pH (7.4) and are increasingly vulnerable to alkaline extracellular pH (8.4), during which their excitability increased further. Under normal pH conditions, an abnormal negative shift in the voltage-dependencies of HCN (hyperpolarization-activated cyclic nucleotide-gated) and calcium channels in the CA1 neurons of Mecp2 (-/y) mice was observed. Alkaline pH also enhanced excitability in wild-type (WT) CA1 neurons through modulation of the voltage dependencies of HCN- and calcium channels. Additionally alkaline pH augmented spontaneous glutamate release and burst firing in WT CA1 neurons. Conversely, acidic pH (6.4) and 8 mM Mg2+ exerted the opposite effect, and diminished hyperexcitability in Mecp2 (-/y) CA1 neurons. We propose that the observed effects of pH and Mg2+ are mediated by changes in the neuronal membrane surface potential, which consecutively modulates the gating of HCN and calcium channels. The results provide insight to pivotal cellular mechanisms that can regulate neuronal excitability and help to devise treatment strategies for hyperexcitability induced symptoms of Rett syndrome. PMID:29621262

Hyperventilation in Patients With Focal Epilepsy: Electromagnetic Tomography, Functional Connectivity and Graph Theory - A Possible Tool in Epilepsy Diagnosis?

PubMed

Mazzucchi, Edoardo; Vollono, Catello; Losurdo, Anna; Testani, Elisa; Gnoni, Valentina; Di Blasi, Chiara; Giannantoni, Nadia M; Lapenta, Leonardo; Brunetti, Valerio; Della Marca, Giacomo

2017-01-01

Hyperventilation (HV) is a commonly used electroencephalogram activation method. We analyzed EEG recordings in 22 normal subjects and 22 patients with focal epilepsy of unknown cause. We selected segments before (PRE), during (HYPER), and 5 minutes after (POST) HV. To analyze the neural generators of EEG signal, we used standard low-resolution electromagnetic tomography (sLORETA software). We then computed EEG lagged coherence, an index of functional connectivity, between 19 regions of interest. A weighted graph was built for each band in every subject, and characteristic path length (L) and clustering coefficient (C) have been computed. Statistical comparisons were performed by means of analysis of variance (Group X Condition X Band) for mean lagged coherence, L and C. Hyperventilation significantly increases EEG neural generators (P < 0.001); the effect is particularly evident in cingulate cortex. Functional connectivity was increased by HV in delta, theta, alpha, and beta bands in the Epileptic group (P < 0.01) and only in theta band in Control group. Intergroup analysis of mean lagged coherence, C and L, showed significant differences for Group (P < 0.001), Condition (P < 0.001), and Band (P < 0.001). Analysis of variance for L also showed significant interactions: Group X Condition (P = 0.003) and Group X Band (P < 0.001). In our relatively small group of epileptic patients, HV is associated with activation of cingulate cortex; moreover, it modifies brain connectivity. The significant differences in mean lagged coherence, path length, and clustering coefficient permit to hypothesize that this activation method leads to different brain connectivity patterns in patients with epilepsy when compared with normal subjects. If confirmed by other studies involving larger populations, this analysis could become a diagnostic tool in epilepsy.

A simple method for isocapnic hyperventilation evaluated in a lung model.

PubMed

Hallén, K; Stenqvist, O; Ricksten, S-E; Lindgren, S

2016-05-01

Isocapnic hyperventilation (IHV) has the potential to increase the elimination rate of anaesthetic gases and has been shown to shorten time to wake-up and post-operative recovery time after inhalation anaesthesia. In this bench test, we describe a technique to achieve isocapnia during hyperventilation (HV) by adding carbon dioxide (CO2) directly to the breathing circuit of a standard anaesthesia apparatus with standard monitoring equipment. Into a mechanical lung model, carbon dioxide was added to simulate a CO2 production (V(CO2)) of 175, 200 and 225 ml/min. Dead space (V(D)) volume could be set at 44, 92 and 134 ml. From baseline ventilation (BLV), HV was achieved by doubling the minute ventilation and fresh gas flow for each level of V(CO2), and dead space. During HV, CO2 was delivered (D(CO2)) by a precision flow meter via a mixing box to the inspiratory limb of the anaesthesia circuit to achieve isocapnia. During HV, the alveolar ventilation increased by 113 ± 6%. Tidal volume increased by 20 ± 0.1% during IHV irrespective of V(D) and V(CO2) level. D(CO2) varied between 147 ± 8 and 325 ± 13 ml/min. Low V(CO2) and large V(D) demanded a greater D(CO2) administration to achieve isocapnia. The FICO2 level during IHV varied between 2.3% and 3.3%. It is possible to maintain isocapnia during HV by delivering carbon dioxide through a standard anaesthesia circuit equipped with modern monitoring capacities. From alveolar ventilation, CO2 production and dead space, the amount of carbon dioxide that is needed to achieve IHV can be estimated. © 2015 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Hyperventilation induces sympathetic overactivation in mesial temporal epilepsy.

PubMed

Assenza, Giovanni; Mecarelli, Oriano; Tombini, Mario; Pulitano, Patrizia; Pellegrino, Giovanni; Benvenga, Antonella; Assenza, Federica; Campana, Chiara; Di Pino, Giovanni; Di Lazzaro, Vincenzo

2015-02-01

Hyperventilation (HV) during electroencephalography (EEG) is a standard clinical procedure to trigger seizures in patients affected by mesial temporal lobe epilepsy (MTLE). Despite the pathophysiology of this susceptibility to HV is not definitively understood, it may be hypothesized to be related to ictal and interictal sympathetic nervous system abnormalities, the presence of which is well known in MTLE patients. In order to test this hypothesis we investigated the HV effect on heart rate variability (HRV) in a group of MTLE patients, compared to a matched group of healthy controls. Forty patients affected by MTLE and 40 age- and sex-matched controls were enrolled in the study. In those subjects, a standard electroencephalographic recording has been acquired and the high and the low frequency components (HF, LF) of heart rate variability (HRV) and their ratio (LF/HF) have been analyzed at rest and during the HV. Indeed, LF/HF is a reliable index of sympathetic tone modulation. HRV did not differ between MTLE and healthy subjects at rest, whereas HV induced a significant LF/HF increase only in MTLE. Within the MTLE group, males showed higher LF/HF increase during HV respect to females, while no differences related to the side of the epileptic focus were found. MTLE patients showed an increased sympathetic response to HV compared to healthy subjects. HRV analysis points towards an autonomic overactivation as a pathophysiological pathway subtending seizure triggered by hyperventilation in MTLE. Autonomic susceptibility in MTLE may help to explain the increased prevalence of arrhythmic events in these patients, potentially predisposing to Sudden Unexpected Death in Epilepsy (SUDEP). Copyright © 2014 Elsevier B.V. All rights reserved.

Feasibility and Efficacy of an mHealth Game for Managing Anxiety: "Flowy" Randomized Controlled Pilot Trial and Design Evaluation.

PubMed

Pham, Quynh; Khatib, Yasmin; Stansfeld, Stephen; Fox, Simon; Green, Tobias

2016-02-01

Meeting the complex needs of patients with chronic common mental health disorders (CMHDs) may be the greatest challenge facing organized medical practice. On the basis of a well-established and proven theoretical foundation for controlled respiration as a behavioral intervention for CMHDs, as well as preliminary evidence that gamification can improve health outcomes through increasing patient engagement, this randomized controlled pilot study evaluated the feasibility and clinical efficacy of a mobile health game called "Flowy" ( www.flowygame.com ) that digitally delivered breathing retraining exercises for anxiety, panic, and hyperventilation symptom management. We designed an unblinded, Web-based, parallel-group randomized controlled trial focusing on feasibility, clinical efficacy, and design proof of concept. In the intervention condition (n = 31), participants received free access to "Flowy" for 4 weeks. In the control condition (n = 32), participants were placed on a waitlist for 4 weeks before being offered free access to "Flowy." Online measurements using psychological self-report questionnaires were made at 2 and 4 weeks post-baseline. At trial conclusion, participants found "Flowy" acceptable as an anxiety management intervention. "Flowy" engaged participants sufficiently to endorse proactive gameplay. Intent-to-treat analysis revealed a reduction in anxiety, panic, and self-report hyperventilation scores in both trial arms, with the intervention arm experiencing greater quality of life. Participants perceived "Flowy" as a fun and useful intervention, proactively used "Flowy" as part of their care, and would recommend "Flowy" to family and friends. Our results suggest that a digital delivery of breathing retraining exercises through a mobile health game can manage anxiety, panic, and hyperventilation symptoms associated with CMHDs.

Reversible central neural hyperexcitability: an electroencephalographic clue to hypocalcaemia.

PubMed

Patel, Bhagyadhan A; Chakor, Rahul T; Kothari, Kaumil V; Nadaf, Swaleha

2017-08-01

A 23-year-old male patient presented with cognitive decline and seizures. Examination revealed Chvostek's and Trousseau's signs. Investigations revealed hypocalcaemia, hyperphosphatemia and normal intact parathyroid hormone levels. Imaging showed calcifications in bilateral basal ganglia, thalamus and dentate nuclei. Interictal electroencephalogram showed theta range slowing of background activity and bilateral temporo-occipital, irregular, sharp and slow wave discharges, which accentuated during hyperventilation, photic stimulation and eye closure. Appearance of epileptiform discharges after eye closure, hyperventilation and photic stimulation may suggest presence of central neural hyperexcitability due to hypocalcaemia. These features may be an equivalent of peripheral neuromuscular hyperexcitability (Chvostek's and Trousseau's signs) that occurs in hypocalcaemia. The clinical and electroencephalographic features completely reversed with correction of serum calcium without antiepileptic medications. It is important for clinicians to recognise these reversible changes, as it can help to avoid misdiagnosis and long-term administration of antiepileptic becomes unnecessary. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Hyperthermic-induced hyperventilation and associated respiratory alkalosis in humans.

PubMed

Abbiss, Chris R; Nosaka, Kazunori; Laursen, Paul B

2007-05-01

The purpose of this study was to determine if increased environmental heat leads to hyperthermic-induced hypocapnia and associated alkalosis during prolonged self-paced cycling. Nine male cyclists completed three 100 km stochastic time trials in hot (34 degrees C), neutral (22 degrees C) and cold (10 degrees C) environments. Intermittent measurements of rectal and skin temperature, expired gases, blood pH, PaCO(2), PaO(2), and bicarbonate were made throughout. Rectal temperature increased significantly throughout all trials (P < 0.001) and was significantly correlated with increases in the ventilatory equivalent for carbon dioxide (Ve/ VCo2; r = 0.77; P < 0.001) and blood pH (r = 0.69; P < 0.05). Rectal temperature was also negatively correlated with a reduction in PaCO(2) (r = -0.80; P < 0.001). PaO(2) and bicarbonate concentration remained constant throughout all trials. This study has shown that prolonged self-paced cycling is associated with a hyperthermic-induced hyperventilation, causing a decrease in arterialized carbon dioxide tension and consequential respiratory alkalosis.

Hyperventilation, cerebral perfusion, and syncope.

PubMed

Immink, R V; Pott, F C; Secher, N H; van Lieshout, J J

2014-04-01

This review summarizes evidence in humans for an association between hyperventilation (HV)-induced hypocapnia and a reduction in cerebral perfusion leading to syncope defined as transient loss of consciousness (TLOC). The cerebral vasculature is sensitive to changes in both the arterial carbon dioxide (PaCO2) and oxygen (PaO2) partial pressures so that hypercapnia/hypoxia increases and hypocapnia/hyperoxia reduces global cerebral blood flow. Cerebral hypoperfusion and TLOC have been associated with hypocapnia related to HV. Notwithstanding pronounced cerebrovascular effects of PaCO2 the contribution of a low PaCO2 to the early postural reduction in middle cerebral artery blood velocity is transient. HV together with postural stress does not reduce cerebral perfusion to such an extent that TLOC develops. However when HV is combined with cardiovascular stressors like cold immersion or reduced cardiac output brain perfusion becomes jeopardized. Whether, in patients with cardiovascular disease and/or defect, cerebral blood flow cerebral control HV-induced hypocapnia elicits cerebral hypoperfusion, leading to TLOC, remains to be established.

Eucapnic Voluntary Hyperventilation to Detect Exercise-Induced Bronchoconstriction in Cystic Fibrosis.

PubMed

Kirkby, Stephen E; Hayes, Don; Parsons, Jonathan P; Wisely, Clayton E; Kopp, Ben; McCoy, Karen S; Mastronarde, John G

2015-10-01

Exercise-induced bronchoconstriction (EIB) has not been well studied in cystic fibrosis (CF), and eucapnic voluntary hyperventilation (EVH) testing has not been used as an objective assessment of EIB in CF to date. A prospective cohort pilot study was completed where standard EVH testing was completed by 10 CF patients with forced expiratory volume in 1 s (FEV1) ≥70% of predicted. All patients also completed a cardiopulmonary exercise test (CPET) with pre- and post-CPET spirometry as a comparative method of detecting EIB. No adverse events occurred with EVH testing. A total of 20% (2/10) patients were diagnosed with EIB by means of EVH. Both patients had clinical symptoms consistent with EIB. No patient had a CPET-based exercise challenge consistent with EIB. EVH testing was safe and effective in the objective assessment for EIB in patients with CF who had well-preserved lung function. It may be a more sensitive method of detecting EIB then exercise challenge.

Effect of hypoxic breathing on cutaneous temperature recovery in man

NASA Astrophysics Data System (ADS)

Fahim, Mohammad

1992-03-01

Effect of hypoxia (12% O2) on skin temperature recovery was studied on healthy young men. Forty male volunteers free of any respiratory disorder were randomly selected to participate in the study. Skin temperature, peripheral blood flow, heart rate and end expiratory PO2 and PCO2 were measured. During hyoxic ventilation the peripheral blood flow was reduced and a corresponding drop in skin temperature occurred. This was partly due to hyperventilation associated with hypoxic ventilation. The recovery of skin temperature after cooling the hand for 2 min in cold water (10 12° C) took 5.5±0.1 min during normal air breathing; during hypoxic ventilation even after 9.1±0.3 min when the skin temperature recovery curve plateaued, the skin temperature remained about 2° C below control. The results of the present investigation indicate that hypoxia interferes with the normal functioning of the thermoregulatory mechanism in man. Hyperventilation associated with hypoxic ventilation is also partly responsible for incomplete recovery of skin temperature.

Characterization of Ventilatory Modes in Dragonfly Nymph

NASA Astrophysics Data System (ADS)

Roh, Chris; Saxton-Fox, Theresa; Gharib, Morteza

2013-11-01

A dragonfly nymph's highly modified hindgut has multiple ventilatory modes: hyperventilation (i.e. jet propulsion), gulping ventilation (extended expiratory phase) and normal ventilation. Each mode involves dynamic manipulation of the exit diameter and pressure. To study the different fluid dynamics associated with the three modes, Anisopteran larvae of the family Aeshnidae were tethered onto a rod for flow visualization. The result showed distinct flow structures. The hyperventilation showed a highly turbulent and powerful jet that occurred at high frequency. The gulping ventilation produced a single vortex at a moderate frequency. The normal ventilation showed two distinct vortices, a low-Reynolds number vortex, followed by a high-Reynolds number vortex. Furthermore, a correlation of the formation of the vortices with the movement of the sternum showed that the dragonfly is actively controlling the timing and the speed of the vortices to have them at equal distance from the jet exit at the onset of inspiration. This behavior prevents inspiration of the oxygen deficient expirated water, resulting in the maximization of the oxygen intake. Supported by NSF GRFP.

The body comes to family therapy: Treatment of a school-aged boy with hyperventilation-induced non-epileptic seizures.

PubMed

Kozlowska, Kasia; Chudleigh, Catherine; Elliott, Bronwen; Landini, Andrea

2016-10-01

We present the case of a 10-year-old boy, Evan, where a knock to the head activated memories of past bullying, causing intense distress, activation of the body's stress-regulation systems and recurrent hospital presentations with hyperventilation-induced non-epileptic seizures. We describe the initial assessment session that enabled Evan and his family to understand the context for Evan's non-epileptic seizures, to engage with the therapeutic team and to collaborate in the implementation of a mind-body multimodal family-based intervention. Once the physical symptoms had been addressed therapeutically, we explored possible dangers within the family and school systems and we worked with Evan and his family to increase his ability to access comfort and protection from his parents. Our short hospital intervention highlighted the importance of ongoing therapeutic work with Evan and the family and laid the foundation stones for the next part of the family's therapeutic journey. © The Author(s) 2015.

One-dimensional model for the intracranial pulse morphological analysis during hyperventilation and CO2 inhalation tests

NASA Astrophysics Data System (ADS)

Ryu, Jaiyoung; Hu, Xiao; Shadden, Shawn C.

2015-11-01

The brain's CO2 reactivity mechanism is coupled with cerebral autoregulation and other unique features of cerebral hemodynamics. We developed a one-dimensional nonlinear model of blood flow in the cerebral arteries coupled to lumped parameter (LP) networks. The LP networks incorporate cerebral autoregulation, CO2 reactivity, intracranial pressure, cerebrospinal fluid, and cortical collateral blood flow models. The model was used to evaluate hemodynamic variables (arterial deformation, blood velocity and pressure) in the cerebral vasculature during hyperventilation and CO2 inhalation test. Tests were performed for various arterial blood pressure (ABP) representing normal and hypotensive conditions. The increase of the cerebral blood flow rates agreed well with the published measurements for various ABP measurements taken during clinical CO2 reactivity tests. The changes in distal vasculature affected the reflected pulse wave energy, which caused the waveform morphological changes at the middle cerebral, common and internal carotid arteries. The pulse morphological analysis demonstrated agreement with previous clinical measurements for cerebral vasoconstriction and vasodilation.

Medical Handbook for Pilots.

ERIC Educational Resources Information Center

Federal Aviation Administration (DOT), Washington, DC.

This handbook provides information on an airline pilot's physical and mental status and related medical factors which may affect his/her performance. Contents include information on the physical examination for pilots, the flyer's environment, hypoxia, hyperventilation, gas in the body, the ears, alcohol, drugs and flying, carbon monoxide, vision,…

DECISION-SUPPORT SOFTWARE FOR SOIL VAPOR EXTRACTION TECHNOLOGY APPLICATION: HYPERVENTILATE

EPA Science Inventory

The U.S. Environmental Protection Agency (EPA) estimate* that 15% to 20% of the approximately 1.7 million underground storage tank (UST) systems containing petroleum products are either leaking or will leak In the near future. These UST systems could pose a serious threat to p...

Breathing exercises for dysfunctional breathing/hyperventilation syndrome in adults.

PubMed

Jones, Mandy; Harvey, Alex; Marston, Louise; O'Connell, Neil E

2013-05-31

Dysfunctional breathing/hyperventilation syndrome (DB/HVS) is a respiratory disorder, psychologically or physiologically based, involving breathing too deeply and/or too rapidly (hyperventilation) or erratic breathing interspersed with breath-holding or sighing (DB). DB/HVS can result in significant patient morbidity and an array of symptoms including breathlessness, chest tightness, dizziness, tremor and paraesthesia. DB/HVS has an estimated prevalence of 9.5% in the general adult population, however, there is little consensus regarding the most effective management of this patient group. (1) To determine whether breathing exercises in patients with DB/HVS have beneficial effects as measured by quality of life indices (2) To determine whether there are any adverse effects of breathing exercises in patients with DB/HVS SEARCH METHODS: We identified trials for consideration using both electronic and manual search strategies. We searched CENTRAL, MEDLINE, EMBASE, and four other databases. The latest search was in February 2013. We planned to include randomised, quasi-randomised or cluster randomised controlled trials (RCTs) in which breathing exercises, or a combined intervention including breathing exercises as a key component, were compared with either no treatment or another therapy that did not include breathing exercises in patients with DB/HVS. Observational studies, case studies and studies utilising a cross-over design were not eligible for inclusion.We considered any type of breathing exercise for inclusion in this review, such as breathing control, diaphragmatic breathing, yoga breathing, Buteyko breathing, biofeedback-guided breathing modification, yawn/sigh suppression. Programs where exercises were either supervised or unsupervised were eligible as were relaxation techniques and acute-episode management, as long as it was clear that breathing exercises were a key component of the intervention.We excluded any intervention without breathing exercises or where breathing exercises were not key to the intervention. Two review authors independently checked search results for eligible studies, assessed all studies that appeared to meet the selection criteria and extracted data. We used standard procedures recommended by The Cochrane Collaboration. We included a single RCT assessed at unclear risk of bias, which compared relaxation therapy (n = 15) versus relaxation therapy and breathing exercises (n = 15) and a no therapy control group (n = 15).Quality of life was not an outcome measure in this RCT, and no numerical data or statistical analysis were presented in this paper. A significant reduction in the frequency and severity of hyperventilation attacks in the breathing exercise group compared with the control group was reported. In addition, a significant difference in frequency and severity of hyperventilation attacks between the breathing and relaxation group was reported. However, no information could be extracted from the paper regarding the size of the treatment effects. The results of this systematic review are unable to inform clinical practice, based on the inclusion of only one small, poorly reported RCT. There is no credible evidence regarding the effectiveness of breathing exercises for the clinical symptoms of DB/HVS. It is currently unknown whether these interventions offer any added value in this patient group or whether specific types of breathing exercise demonstrate superiority over others. Given that breathing exercises are frequently used to treat DB/HVS, there is an urgent need for further well designed clinical trials in this area. Future trials should conform to the CONSORT statement for standards of reporting and use appropriate, validated outcome measures. Trial reports should also ensure full disclosure of data for all important clinical outcomes.

The Role of Hemispheral Asymmetry and Regional Activity of Quantitative EEG in Children with Stuttering

ERIC Educational Resources Information Center

Ozge, Aynur; Toros, Fevziye; Comelekoglu, Ulku

2004-01-01

We investigated the role of delayed cerebral maturation, hemisphere asymmetry and regional differences in children with stuttering and healthy controls during resting state and hyperventilation, using conventional EEG techniques and quantitative EEG (QEEG) analysis. This cross-sectional case control study included 26 children with stuttering and…

An Analogue Assessment of Repetitive Hand Behaviours in Girls and Young Women with Rett Syndrome

ERIC Educational Resources Information Center

Wales, L.; Charman, T.; Mount, R. H.

2004-01-01

Rett syndrome is a neuro-developmental disorder that almost exclusively affects females. In addition to neuro-developmental regression and loss of hand skills, apraxia, deceleration of head growth, and increasing spasticity and scoliosis, a number of behavioural features are also seen, including stereotypic hand movements, hyperventilation and…

Breathing hot humid air induces airway irritation and cough in patients with allergic rhinitis.

PubMed

Khosravi, Mehdi; Collins, Paul B; Lin, Ruei-Lung; Hayes, Don; Smith, Jaclyn A; Lee, Lu-Yuan

2014-07-01

We studied the respiratory responses to an increase in airway temperature in patients with allergic rhinitis (AR). Responses to isocapnic hyperventilation (40% of maximal voluntary ventilation) for 4min of humidified hot air (HA; 49°C) and room air (RA; 21°C) were compared between AR patients (n=7) and healthy subjects (n=6). In AR patients, cough frequency increased pronouncedly from 0.10±0.07 before to 2.37±0.73 during, and 1.80±0.79coughs/min for the first 8min after the HA challenge, but not during the RA challenge. In contrast, neither HA nor RA had any significant tussive effect in healthy subjects. The HA challenge also caused respiratory discomfort (mainly throat irritation) measured by the handgrip dynamometry in AR patients, but not in healthy subjects. Bronchoconstriction was not detected after the HA challenge in either group of subjects. In conclusion, hyperventilation of HA triggered vigorous cough response and throat irritation in AR patients, indicating the involvement of sensory nerves innervating upper airways. Copyright © 2014 Elsevier B.V. All rights reserved.

Low serum concentrations of vitamin B6 and iron are related to panic attack and hyperventilation attack.

PubMed

Mikawa, Yasuhito; Mizobuchi, Satoshi; Egi, Moritoki; Morita, Kiyoshi

2013-01-01

Patients undergoing a panic attack (PA) or a hyperventilation attack (HVA) are sometimes admitted to emergency departments (EDs). Reduced serotonin level is known as one of the causes of PA and HVA. Serotonin is synthesized from tryptophan. For the synthesis of serotonin, vitamin B6 (Vit B6) and iron play important roles as cofactors. To clarify the pathophysiology of PA and HVA, we investigated the serum levels of vitamins B2, B6, and B12 and iron in patients with PA or HVA attending an ED. We measured each parameter in 21 PA or HVA patients and compared the values with those from 20 volunteers. We found that both Vit B6 and iron levels were significantly lower in the PA/HVA group than in the volunteer group. There was no significant difference in the serum levels of vitamins B2 or B12. These results suggest that low serum concentrations of Vit B6 and iron are involved in PA and HVA. Further studies are needed to clarify the mechanisms involved in such differences.

Analysis of the influence location of the fiber optic sensor on the measurement and determination the heart rate of the human body

NASA Astrophysics Data System (ADS)

Nedoma, Jan; Fajkus, Marcel; Martinek, Radek; Cubik, Jakub; Kepak, Stanislav; Vanus, Jan; Zboril, Ondrej; Vasinek, Vladimir

2017-10-01

Authors of this article focused on the analysis of the influence location of the fiber-optic sensor on the measurement and determination the heart rate of the human body. The sensor uses a Fiber Bragg Grating (FBG) and is encapsulated in the polymer polydimethylsiloxane (PDMS). The combination of fiber-optic technology and its encapsulation in a polymer PDMS allows the use of the sensor e.g. in magnetic resonance environments (MRI). Among currently solved doctors requirements belongs field focusing on the study of hyperventilation and panic attacks of patients during MRI examination due to their very frequent occurrence. Proposed FBG sensor can help doctors to predict (based on heart rate) hyperventilation and panic attacks of patients during MRI examinations. For the most accurate determination of the heart rate, it is necessary to know the influence location of the sensor on the human body. The sensor functionality and analysis of the sensor placement on the heart rate has been verified by a series of real experimental measurements of test subjects in laboratory environment.

Epidemiology of central sleep apnoea in heart failure.

PubMed

Naughton, Matthew T

2016-03-01

Central sleep apnoea occurs in about a third of patients with reduced systolic heart failure and is a marker of increased mortality. Such patients usually are older males with advanced heart failure (i.e., high pulmonary wedge pressure), often in atrial fibrillation, with evidence of hyperventilation (i.e., low PaCO2) in the absence of hypoxemia. Characteristically, ventilation waxes and wanes in a sinusoidal pattern, with mild hypoxemia, occurring in the lighter levels of sleep usually when supine. Snoring may also occur in central sleep apnoea, often at the peak of hyperventilation, sometimes contributing to the confusion or overlap with obstructive sleep apnoea. Central sleep apnoea is associated with orthopnoea, paroxysmal nocturnal dyspnoea and an oscillatory respiratory pattern with an incremental cardiopulmonary exercise study. Importantly, heart failure therapies (e.g., afterload reduction, diuresis, pacemakers, transplantation) attenuate central sleep apnoea. Night to night variability in severity of central sleep apnoea may occur with changes in patients' posture during sleep (less severe when sleeping on-side or upright). Crown Copyright © 2016. Published by Elsevier Ireland Ltd. All rights reserved.

Anticipation of interoceptive threat in highly anxiety sensitive persons.

PubMed

Melzig, Christiane A; Michalowski, Jaroslaw M; Holtz, Katharina; Hamm, Alfons O

2008-10-01

Anticipatory anxiety plays a major role in the etiology of panic disorder. Although anticipatory anxiety elicited by expectation of interoceptive cues is specifically relevant for panic patients, it has rarely been studied. Using a population analogue in high fear of such interoceptive arousal sensations (highly anxiety sensitive persons) we evaluated a new experimental paradigm to assess anticipatory anxiety during anticipation of interoceptive (somatic sensations evoked by hyperventilation) and exteroceptive (electric shock) threat. Symptom reports, autonomic arousal, and defensive response mobilization (startle eyeblink response) were monitored during threat and matched safe conditions in 26 highly anxiety sensitive persons and 22 controls. The anticipation of exteroceptive threat led to a defensive and autonomic mobilization as indexed by a potentiation of the startle response and an increase in skin conductance level in both experimental groups. During interoceptive threat, however, only highly anxiety sensitive persons but not the controls exhibited a startle response potentiation as well as autonomic activation. The anticipation of a hyperventilation procedure thus seems a valid paradigm to investigate anticipatory anxiety elicited by interoceptive cues in the clinical context.

Bronchoconstriction induced by hyperventilation with humidified hot air: role of TRPV1-expressing airway afferents.

PubMed

Lin, Ruei-Lung; Hayes, Don; Lee, Lu-Yuan

2009-06-01

A recent study by our laboratory has shown that an increase in intrathoracic temperature activates vagal pulmonary C-fibers. Because these afferents are known to elicit reflex bronchoconstriction upon stimulation, this study was carried out to investigate if an increase in airway temperature within the physiological range alters bronchomotor tone. Adult guinea pigs were anesthetized and mechanically ventilated via a tracheal tube. After the lung had been hyperventilated with humidified hot air (HHA) for 4 min, the tracheal temperature was elevated from 36.4 to 40.5 degrees C, which induced an immediate bronchoconstriction, increasing total pulmonary resistance (R(L)) to 177 +/- 10% and decreasing dynamic lung compliance to 81 +/- 6% of their respective baselines. The increase in R(L) returned spontaneously toward the baseline in <10 min and was reproducible in the same animals. There were no difference in the responses whether the humidity was generated from distilled water or isotonic saline. In contrast, hyperventilation with humidified air at room temperature did not cause any increase in R(L). The increase in R(L) caused by HHA was attenuated by 65.9% after a pretreatment with atropine alone and by 72.0% after a pretreatment with a combination of atropine and neurokinin receptor type 1 and 2 antagonists. In addition, capsazepine, a selective transient receptor potential vanilloid type 1 (TRPV1) antagonist, reduced the HHA-induced increase in R(L) by 64.1% but did not abolish it. However, pretreatment with formoterol, a beta(2)-agonist, completely prevented the HHA-induced bronchoconstriction. These results indicate that the increase in airway temperature induced transient airway constriction in guinea pigs. Approximately two-thirds of the increase in bronchomotor tone was mediated through the cholinergic reflex, which was probably elicited by the activation of TRPV1-expressing airway afferents. The remaining bronchoconstriction was caused by other, yet unidentified factors.

Cerebral blood flow and carbon dioxide reactivity in children with bacterial meningitis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ashwal, S.; Stringer, W.; Tomasi, L.

1990-10-01

We examined total and regional cerebral blood flow (CBF) by stable xenon computed tomography in 20 seriously ill children with acute bacterial meningitis to determine whether CBF was reduced and to examine the changes in CBF during hyperventilation. In 13 children, total CBF was normal (62 +/- 20 ml/min/100 gm) but marked local variability of flow was seen. In five other children, total CBF was significantly reduced (26 +/- 10 ml/min/100 gm; p less than 0.05), with flow reduced more in white matter (8 +/- 5 ml/min/100 gm) than in gray matter (30 +/- 15 ml/min/100 gm). Autoregulation of CBFmore » appeared to be present in these 18 children within a range of mean arterial blood pressure from 56 to 102 mm Hg. In the remaining two infants, brain dead within the first 24 hours, total flow was uniformly absent, averaging 3 +/- 3 ml/min/100 gm. In seven children, CBF was determined at two carbon dioxide tension (PCO2) levels: 40 (+/- 3) mm Hg and 29 (+/- 3) mm Hg. In six children, total CBF decreased 33%, from 52 (+/- 25) to 35 (+/- 15) ml/min/100 gm; the mean percentage of change in CBF per millimeter of mercury of PCO2 was 3.0%. Regional variability of perfusion to changes in PCO2 was marked in all six children. The percentage of change in CBF per millimeter of mercury of PCO2 was similar in frontal gray matter (3.1%) but higher in white matter (4.5%). In the seventh patient a paradoxical response was observed; total and regional CBF increased 25% after hyperventilation. Our findings demonstrate that (1) CBF in children with bacterial meningitis may be substantially decreased globally, with even more variability noted regionally, (2) autoregulation of CBF is preserved, (3) CBF/CO2 responsitivity varies among patients and in different regions of the brain in the same patient, and (4) hyperventilation can reduce CBF below ischemic thresholds.« less

Cerebrovascular response to acute hypocapnic and eucapnic hypoxia in normal man

PubMed Central

Shapiro, William; Wasserman, Albert J.; Baker, James P.; Patterson, John L.

1970-01-01

Alterations in human cerebral blood flow and related blood constituents were studied during exposure to acute hypoxia. Observations were made during serial inhalation of decreasing O2 concentrations with and without maintenance of normocarbia, during 8 min inhalation of 10% O2, and after hyperventilation at an arterial PO2 of about 40 mm Hg. In the range of hypoxemia studied, from normal down to arterial PO2 of about 40 mm Hg, the magnitude of the cerebral vasodilator response to hypoxia appeared to be largely dependent upon the coexisting arterial CO2 tension. The mean slope of the increase in cerebral blood flow with decreasing arterial O2 tension rose more quickly (P < 0.05) when eucapnia was maintained when compared with the slope derived under similar hypoxic conditions without maintenance of eucapnia. When 12 subjects inhaled 10% oxygen, cerebral blood flow rose to more than 135% of control in four whose mean decrease in arterial CO2 tension was - 2.0 mm Hg. The remaining eight had flows ranging from 97 to 120% of control, and their mean decrease in CO2 tension was - 5.1 mm Hg. When mean arterial PO2 was 37 mm Hg, hyperventilation was carried out in 10 subjects. Arterial PO2 increased insignificantly, arterial PCO2 declined from 34 to 27 mm Hg (P < 0.05), and cerebral blood flow which had been 143% of control decreased to 109%, a figure not significantly different from control. These data demonstrate the powerful counterbalancing constrictor effects of modest reductions in CO2 tension on the vasodilator influence of hypoxia represented by arterial PO2 reductions to about 40 mm Hg. Indeed, mild hyperventilation completely overcame the vasodilator effect provided by an arterial O2 tension as low as 40 mm Hg. The effects of hypoxia on the control of the cerebral circulation must be analyzed in terms of the effects of any associated changes in CO2 tension. PMID:5480859

TRPV1 deletion exacerbates hyperthermic seizures in an age-dependent manner in mice.

PubMed

Barrett, Karlene T; Wilson, Richard J A; Scantlebury, Morris H

2016-12-01

Febrile seizures (FS) are the most common seizure disorder to affect children. Although there is mounting evidence to support that FS occur when children have fever-induced hyperventilation leading to respiratory alkalosis, the underlying mechanisms of hyperthermia-induced hyperventilation and links to FS remain poorly understood. As transient receptor potential vanilloid-1 (TRPV1) receptors are heat-sensitive, play an important role in adult thermoregulation and modulate respiratory chemoreceptors, we hypothesize that TRPV1 activation is important for hyperthermia-induced hyperventilation leading to respiratory alkalosis and decreased FS thresholds, and consequently, TRPV1 KO mice will be relatively protected from hyperthermic seizures. To test our hypothesis we subjected postnatal (P) day 8-20 TRPV1 KO and C57BL/6 control mice to heated dry air. Seizure threshold temperature, latency and the rate of rise of body temperature during hyperthermia were assessed. At ages where differences in seizure thresholds were identified, head-out plethysmography was used to assess breathing and the rate of expired CO 2 in response to hyperthermia, to determine if the changes in seizure thresholds were related to respiratory alkalosis. Paradoxically, we observed a pro-convulsant effect of TRPV1 deletion (∼4min decrease in seizure latency), and increased ventilation in response to hyperthermia in TRPV1 KO compared to control mice at P20. This pro-convulsant effect of TRPV1 absence was not associated with an increased rate of expired CO 2 , however, these mice had a more rapid rise in body temperature following exposure to hyperthermia than controls, and the expected linear relationship between body weight and seizure latency was absent. Based on these findings, we conclude that deletion of the TRPV1 receptor prevents reduction in hyperthermic seizure susceptibility in older mouse pups, via a mechanism that is independent of hyperthermia-induced respiratory alkalosis, but possibly involves impaired development of thermoregulatory mechanisms, although at present the mechanism remain unknown. Copyright © 2016 Elsevier B.V. All rights reserved.

Cardiopulmonary and arterial baroreceptor unloading during passive hyperthermia does not contribute to hyperthermia-induced hyperventilation

PubMed Central

Lucas, Rebekah A. I.; Pearson, James; Schlader, Zachary J.; Crandall, Craig G.

2016-01-01

This study tested the hypothesis that baroreceptor unloading during passive hyperthermia contributes to increases in ventilation and decreases in end-tidal partial pressure of carbon dioxide (PET,CO2) during that exposure. Two protocols were performed, in which healthy subjects underwent passive hyperthermia (increasing intestinal temperature by ~1.8°C) to cause a sustained increase in ventilation and reduction in PET,CO2. Upon attaining hyperthermic hyperventilation, in protocol 1 (n = 10; three females) a bolus (19 ± 2 ml kg−1) of warm (~38°C) isotonic saline was rapidly (5–10 min) infused intravenously to restore reductions in central venous pressure, whereas in protocol 2 (n = 11; five females) phenylephrine was infused intravenously (60–120 μg min−1) to return mean arterial pressure to normothermic levels. In protocol 1, hyperthermia increased ventilation (by 2.2 ± 1.7 l min−1, P < 0.01), while reducing PET,CO2 (by 4 ± 3 mmHg, P = 0.04) and central venous pressure (by 5 ± 1 mmHg, P <0.01). Saline infusion increased central venous pressure by 5 ± 1 mmHg (P < 0.01), restoring it to normothermic values, but did not change ventilation or PET,CO2 (P > 0.05). In protocol 2, hyperthermia increased ventilation (by 5.0 ± 2.7l min−1, P <0.01) and reduced PET ,CO2 (by 5 ± 2 mmHg, P < 0.01) and mean arterial pressure (by 9 ± 7 mmHg, P <0.01). Phenylephrine infusion increased mean arterial pressure by 12 ± 3 mmHg (P < 0.01), restoring it to normothermic values, but did not change ventilation or PET,CO2 (P > 0.05). The absence of a reduction in ventilation upon reloading the cardiopulmonary and arterial baroreceptors to pre-hyperthermic levels indicates that baroreceptor unloading with hyperthermia is unlikely to contribute to hyperthermic hyperventilation in humans. PMID:26299270

Effect of voluntary hypocapnic hyperventilation or moderate hypoxia on metabolic and heart rate responses during high-intensity intermittent exercise.

PubMed

Dobashi, Kohei; Fujii, Naoto; Watanabe, Kazuhito; Tsuji, Bun; Sasaki, Yosuke; Fujimoto, Tomomi; Tanigawa, Satoru; Nishiyasu, Takeshi

2017-08-01

To investigate the effect of voluntary hypocapnic hyperventilation or moderate hypoxia on metabolic and heart rate responses during high-intensity intermittent exercise. Ten males performed three 30-s bouts of high-intensity cycling [Ex1 and Ex2: constant-workload at 80% of the power output in the Wingate anaerobic test (WAnT), Ex3: WAnT] interspaced with 4-min recovery periods under normoxic (Control), hypocapnic or hypoxic (2500 m) conditions. Hypocapnia was developed through voluntary hyperventilation for 20 min prior to Ex1 and during each recovery period. End-tidal CO 2 pressure was lower before each exercise in the hypocapnia than control trials. Oxygen uptake ([Formula: see text]) was lower in the hypocapnia than control trials (822 ± 235 vs. 1645 ± 245 mL min -1 ; mean ± SD) during Ex1, but not Ex2 or Ex3, without a between-trial difference in the power output during the exercises. Heart rates (HRs) during Ex1 (127 ± 8 vs. 142 ± 10 beats min -1 ) and subsequent post-exercise recovery periods were lower in the hypocapnia than control trials, without differences during or after Ex2, except at 4 min into the second recovery period. [Formula: see text] did not differ between the control and hypoxia trials throughout. These results suggest that during three 30-s bouts of high-intensity intermittent cycling, (1) hypocapnia reduces the aerobic metabolic rate with a compensatory increase in the anaerobic metabolic rate during the first but not subsequent exercises; (2) HRs during the exercise and post-exercise recovery periods are lowered by hypocapnia, but this effect is diminished with repeated exercise bouts, and (3) moderate hypoxia (2500 m) does not affect the metabolic response during exercise.

Arterial-to-end-tidal carbon dioxide tension difference in children with congenital heart disease.

PubMed

Choudhury, Minati; Kiran, Usha; Choudhary, Shiv Kumar; Airan, Balram

2006-04-01

This study estimated the arterial-to-end-tidal carbon dioxide tension difference (deltaPaCO2-PE'CO2) in children with congenital heart disease; evaluated whether hyperventilation can reduce this difference; and analyzed the relationship between the difference and the oxygen saturation (SaO2) and hemoglobin level. Prospective clinical study. Tertiary health care center. One hundred patients scheduled for correction of their underlying cardiac defect with either right-to-left or left-to-right intracardiac shunts were divided into 4 groups (n = 25 each): (1) N1, cyanotic with severe pulmonary artery hypertension; (2) N2, cyanotic with normal or decreased pulmonary artery pressure (PAP); (3) N3, acyanotic with normal or mild increases in PAP and severe increases in pulmonary blood flow (PBF); and (4) N4, acyanotic with normal PAP and normal or mild increase in PBF. All the patients received the same anesthetic regimen. The initial settings for tidal volume, respiratory rate, and inspiratory-to-expiratory (I:E) ratio were 10 mL/kg, 15 to 30 breath/min, and inspired time 40% of the total respiratory period with a 10% end-inspiratory pause. After the measurement of oxygen saturation, PO2, Hb, and deltaPaCO2-PE'CO2, all the children were hyperventilated (tidal volume: 14-15 mL/kg, respiratory rate: 5-6 breaths/min more than the initial rate, I:E ratio: same) to observe its effects on the deltaPaCO2-PE'CO2. The deltaPaCO2-PE'CO2, when predicted from the oxygen saturation, hemoglobin concentration, and PaO2, was found to be greater than the observed value in the first 3 groups (p < 0.001); whereas in group N4 these 2 values were comparable. It was also found that the gradient was higher when there was a decrease in SaO2 and an increase in the hemoglobin level. After hyperventilation, in groups N1 and N3, deltaPaCO2-PE'CO2 was decreased when compared with their baseline values; this reduction was not as much as predicted (p = 0.363 and 0.236, respectively). However, in groups N2 and N4 posthyperventilation, the deltaPaCO2-PE'27 CO2 was decreased significantly below their baseline measurements. These decreases were as much predicted. The deltaPaCO2-end-tidal carbon dioxide (PE'CO2) can be increased both in cyanotic and acyanotic children. Increased PAP is as important as increased PBF or right-to-left shunting in producing disorders in carbon dioxide homeostasis. Hyperventilation is of little use in reducing deltaPaCO2-PE'CO2 in children with high PAPs and pulmonary hyperperfusion.

Prognosis in Acute Cerebrovascular Accidents in Relation to Respiratory Pattern and Blood—gas Tensions

PubMed Central

Rout, M. W.; Lane, D. J.; Wollner, L.

1971-01-01

Respiratory pattern and arterial blood gas tensions were assessed in patients with acute cerebrovascular accidents. Hyperventilation, low Pco2, and high arterial pH were associated with a poor prognosis, whereas patients with normal respiratory pattern and blood gas tensions survived. Periodic and Cheyne-Stokes breathing carried an intermediate prognosis. PMID:5091916

The Effect of Hyperventilation on the Ability To Hold One's Breath: Testing the Influence of Beliefs versus Physiology.

ERIC Educational Resources Information Center

Given, Mac F.

1997-01-01

Reports on a simple classroom exercise that investigates whether students' beliefs of what they think should happen influences their measurements. The exercise also provides a framework for discussing the challenges that human belief systems bring to the discipline of using the scientific process. Results suggest that students' preconceived…

Acute Infectious Disease,

DTIC Science & Technology

1984-03-23

accelerated respiration. This tachypnia causes an exaggerated loss of carbon dioxide.3 The respiratory alkalosis that ensues is typically seen during all...with respiratory alkalosis . During periods of heat-induced tachypnia, U’. inorganic phosphates may virtually disappear for a time from urine and sweat...urine and sweat during the period when respiratory alkalosis and hyperventilation are taking place. On the other hand, losses of phosphate may be

The Interactive Role of Anxiety Sensitivity and Pubertal Status in Predicting Anxious Responding to Bodily Sensations among Adolescents

ERIC Educational Resources Information Center

Leen-Feldner, Ellen W.; Reardon, Laura E.; McKee, Laura G.; Feldner, Matthew T.; Babson, Kimberly A.; Zvolensky, Michael J. J.

2006-01-01

The present study examined the interaction between pubertal status and anxiety sensitivity (AS) in predicting anxious and fearful responding to a three-minute voluntary hyperventilation challenge among 124 (57 females) adolescents between the ages of 12 and 17 years (Mage = 15.04; SD = 1.49). As predicted, after controlling for baseline anxiety,…

The new American Heart Association cardiopulmonary resuscitation guidelines: should children and adults have to share?

PubMed

Sherman, Mindy

2007-06-01

The latest American Heart Association guidelines for pediatric cardiopulmonary resuscitation (CPR) were published in December 2005. Changes from the 2000 guidelines were directed toward simplifying CPR. Infants, children, and adults now share the same recommendation for the initial compression:ventilation ratio. This is a significant change for pediatricians trained in the importance of a respiratory etiology of pediatric cardiopulmonary arrest. The present review will focus on the rationale behind these guideline changes. The new guidelines for single rescuer CPR include a compression:ventilation ratio of 30: 2 for both adult and pediatric victims. The impetus for this recommendation is based on recent appreciation for the deleterious effects of hyperventilation as well as an attempt to increase bystander delivery of CPR. The physiologic results of hyperventilation are discussed. The new pediatric basic life support guideline changes are underscored. Research representing the spectrum of opinions on the optimal compression:ventilation ratio, including compression-only CPR, is presented. Although based primarily on adult, animal, and computational models, the new compression:ventilation ratio, recommended for both initial pediatric and adult CPR, is a reasonable recommendation. The simplified CPR guidelines released in 2005 will hopefully contribute to improved bystander delivery of CPR and improved outcome.

The efficacy of routine hyperventilation for seizure activation during prolonged video-electroencephalography monitoring.

PubMed

Abubakr, Abuhuziefa; Ifeayni, Iwuchukwu; Wambacq, Ilse

2010-12-01

Hyperventilation (HV) is considered to be one of the activation procedures that provokes epileptic potentials and clinical seizures. However, the true clinical yield of HV is not well established. We retrospectively reviewed the records of all patients admitted to JFK Hospital, Edison, New Jersey, between October 2001 and December 2004 for long-term video-electroencephalography (EEG). A total of 475 patients (193 males; 282 females; age range 5-89 years) were included in the study. All patients underwent routine 3-minute HV as part of the evaluation of their clinical episodes. During the initial assessment, 165 patients did not experience a seizure event, 92 had non-epileptic events, 16 experienced psychogenic non-epileptic seizures (PNES) and six had a clinical event. During HV, of the 43 patients who had primary generalized epilepsy, nine had an abnormal EEG and two experienced seizures; however, out of the 159 patients who had partial seizures, only one patient demonstrated an abnormal EEG. Our study demonstrates that routine HV generally has a very low yield in our Epilepsy-Monitoring Unit. This finding also lends support to the idea that partial seizures are relatively resistant to HV activation. Copyright © 2010 Elsevier Ltd. All rights reserved.

Quantification of Macrocirculation and Microcirculation in Brain Using Ultrasound Perfusion Imaging.

PubMed

Vinke, Eline J; Eyding, Jens; de Korte, Chris; Slump, Cornelis H; van der Hoeven, Johannes G; Hoedemaekers, Cornelia W E

2018-01-01

The aim of this study was to investigate the feasibility of simultaneous visualization of the cerebral macrocirculation and microcirculation, using ultrasound perfusion imaging (UPI). In addition, we studied the sensitivity of this technique for detecting changes in cerebral blood flow (CBF). We performed an observational study in ten healthy volunteers. Ultrasound contrast was used for UPI measurements during normoventilation and hyperventilation. For the data analysis of the UPI measurements, an in-house algorithm was used to visualize the DICOM files, calculate parameter images and select regions of interest (ROIs). Next, time intensity curves (TIC) were extracted and perfusion parameters calculated. Both volume- and velocity-related perfusion parameters were significantly different between the macrocirculation and the parenchymal areas. Hyperventilation-induced decreases in CBF were detectable by UPI in both the macrocirculation and microcirculation, most consistently by the volume-related parameters. The method was safe, with no adverse effects in our population. Bedside quantification of CBF seems feasible and the technique has a favourable safety profile. Adjustment of current method is required to improve its diagnostic accuracy. Validation studies using a 'gold standard' are needed to determine the added value of UPI in neurocritical care monitoring.

Computer Assisted Diagnosis of Chest Pain. Preliminary Manual

DTIC Science & Technology

1984-04-27

liquid antacids, a fact which assists in diagnosis. Esophageal spasm may follow a meal and is accompanied by dysphagia . The pain is relieved by...treatment. Occasionally, the practitioner will pinpoint a "specific" diagnosis (i.e., esophagitis ) in this category, but in all cases NONSCP is...costochrondritis (Tietze’s syndrome); c) esophagitis ; d) esophageal spasm (" esophageal angina"); e) hyperventilation syndrome; f) psychoneurotic

Pulmonary Stress Induced by Hyperthermia: Role of Airway Sensory Nerves

DTIC Science & Technology

2013-10-01

ABSTRACT Based upon the results obtained from these studies, we can draw the following conclusions: 1) Airway hyperresponsiveness developed in Ova ...hyperthermia in Ova -sensitized rats. The manuscript reporting the results obtained frim this study has been accepted for publication by the Journal of...to increasing airway temperature. Our results showed: 1) In Brown-Norway rats actively sensitized by ovalbumin ( Ova ), isocapnic hyperventilation with

Respiratory Adaptations in Acid-base Disturbances: Role of Cerebral Fluids,

DTIC Science & Technology

1979-06-19

The respiratory and metabolic components of acid-base homeostasis are defined. A quantitative empirical description of the (incomplete) mutual...literature. Respiratory adaptations in steady acid-base disturbances of metabolic origin (hyperventilation with hypocapnia in primary metabolic acidosis, and...hypoventilation with hypercapnia in metabolic alkalosis ) are analyzed as a function of the acidity of the cerebral fluids (cerebrospinal and cerebral interstitial fluid). (Author)

Emergency Interventions After Severe Traumatic Brain Injury in Rats: Effect on Neuropatholgy and Functional Outcome.

DTIC Science & Technology

1999-01-01

practical interventions applicable in the emergency treatment of severe TBI ( respiratory management, temperature control, and sedation) can reduce secondary...during the low cerebral blood flow state immediately after injury coupled with alkalosis may increase the vulnerability of selected neurons to damage...injury. KEYWORDS • head injury • hyperventilation • alkalosis • hippocampus • rat TRAUMATIC brain injury (TBI) is often complicated

Postural hypocapnic hyperventilation is associated with enhanced peripheral vasoconstriction in postural tachycardia syndrome with normal supine blood flow

PubMed Central

Stewart, Julian M.; Medow, Marvin S.; Cherniack, Neil S.; Natelson, Benjamin H.

2015-01-01

Previous investigations have demonstrated a subset of postural tachycardia syndrome (POTS) patients characterized by normal peripheral resistance and blood volume while supine but thoracic hypovolemia and splanchnic blood pooling while upright secondary to splanchnic hyperemia. Such “normal-flow” POTS patients often demonstrate hypocapnia during orthostatic stress. We studied 20 POTS patients (14–23 yr of age) and compared them with 10 comparably aged healthy volunteers. We measured changes in heart rate, blood pressure, heart rate and blood pressure variability, arm and leg strain-gauge occlusion plethysmography, respiratory impedance plethysmography calibrated against pneumotachography, end-tidal partial pressure of carbon dioxide (PetCO2), and impedance plethysmographic indexes of blood volume and blood flow within the thoracic, splanchnic, pelvic (upper leg), and lower leg regional circulations while supine and during upright tilt to 70°. Ten POTS patients demonstrated significant hyperventilation and hypocapnia (POTSHC) while 10 were normocapnic with minimal increase in postural ventilation, comparable to control. While relative splanchnic hypervolemia and hyperemia occurred in both POTS groups compared with controls, marked enhancement in peripheral vasoconstriction occurred only in POTSHC and was related to thoracic blood flow. Variability indexes suggested enhanced sympathetic activation in POTSHC compared with other subjects. The data suggest enhanced cardiac and peripheral sympathetic excitation in POTSHC. PMID:16565300

The Effects of Endotracheal Suctioning with Manual Hyperventilation on Cerebrovascular Status of Closed Head Injured Patients

DTIC Science & Technology

1989-02-02

PERFORMING ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION AFIT STUDENT AT (if applicable) AFIT/CIA Univ of MDI 6c. ADDRESS (City, State...Medicine, Pediatrics, ICU USAF Regional Hospital RAF Lakenheath, England 1987-Present Graduate Student Air Force Institute of Technology University...open or closed head injury to determine the acute physiologic alterations in cerebrovascular status that occurred during chest physiotherapy (CPT). ICP

Development of Medical Adjunctive Treatment for Acute Penetrating Head Injury

DTIC Science & Technology

1988-04-01

surgical procedure performed will naturally depend upon the nature of the injury. In general terms, however, a craniectomy or craniotomy will be performed...ICP cannot be kept under control, even with CSF drainage and mannitol when sedation and pancuronium are withdrawn. Radiological Studies All patients...will be hyperventilated to achieve a pCO2 of not less tan 25 mmHg. Ventricular drainage via the ventriculostomy will be simulta- neously employed. 11

Effect of Six Days of Staging on Physiologic Adjustments and Acute Mountain Sickness During Ascent to 4300 Meters

DTIC Science & Technology

2009-01-01

respiratory alkalosis due to hyperventilation that was partially compensated for by increased excretion of HCO3 to maintain a normal pH following...carbon dioxide; RER, respiratory exchange quotient; Sao2, arterial oxygen saturation; Paco2, partial pressure of capillary-arterialized carbon dioxide...dioxide production; E=O2, ventilatory equivalent for oxygen; E=CO2, ventilatory equivalent for carbon dioxide; RER, respiratory exchange quotient

Hemoglobin P50 During a Simulated Ascent of Mt. Everest, Operation Everest II

DTIC Science & Technology

2007-01-01

With altitude, increased [2,3-DPG] shifts the dissociation curve rightward, but hypocap- nia and alkalosis move it leftward. We determined both...of 30 mmHg. However, in vivo P50 remained between 26 and 27 mmHg throughout due to pro- gressive hypocapnia and alkalosis . Calculations suggest that...were unpredictable at extreme altitude, espe- cially in the face of counterbalancing effects from progressive hyperventilation and alkalosis . It was

Endogenous excitatory drive to the respiratory system in rapid eye movement sleep in cats.

PubMed

Orem, J; Lovering, A T; Dunin-Barkowski, W; Vidruk, E H

2000-09-01

A putative endogenous excitatory drive to the respiratory system in rapid eye movement (REM) sleep may explain many characteristics of breathing in that state, e.g. its irregularity and variable ventilatory responses to chemical stimuli. This drive is hypothetical, and determinations of its existence and character are complicated by control of the respiratory system by the oscillator and its feedback mechanisms. In the present study, endogenous drive was studied during apnoea caused by mechanical hyperventilation. We reasoned that if there was a REM-dependent drive to the respiratory system, then respiratory activity should emerge out of the background apnoea as a manifestation of the drive. Diaphragmatic muscle or medullary respiratory neuronal activity was studied in five intact, unanaesthetized adult cats who were either mechanically hyperventilated or breathed spontaneously in more than 100 REM sleep periods. Diaphragmatic activity emerged out of a background apnoea caused by mechanical hyperventilation an average of 34 s after the onset of REM sleep. Emergent activity occurred in 60 % of 10 s epochs in REM sleep and the amount of activity per unit time averaged approximately 40 % of eupnoeic activity. The activity occurred in episodes and was poorly related to pontogeniculo-occipital waves. At low CO2 levels, this activity was non-rhythmic. At higher CO2 levels (less than 0.5 % below eupnoeic end-tidal percentage CO2 levels in non-REM (NREM) sleep), activity became rhythmic. Medullary respiratory neurons were recorded in one of the five animals. Nineteen of twenty-seven medullary respiratory neurons were excited in REM sleep during apnoea. Excited neurons included inspiratory, expiratory and phase-spanning neurons. Excitation began about 43 s after the onset of REM sleep. Activity increased from an average of 6 impulses s-1 in NREM sleep to 15.5 impulses s-1 in REM sleep. Neuronal activity was non-rhythmic at low CO2 levels and became rhythmic when levels were less than 0.5 % below eupnoeic end-tidal levels in NREM sleep. The level of CO2 at which rhythmic neuronal activity developed corresponded to eupnoeic end-tidal CO2 levels in REM sleep. These results demonstrate an endogenous excitatory drive to the respiratory system in REM sleep and account for rapid and irregular breathing and the lower set-point to CO2 in that state.

Development of an Atlas of Strengths and Establishment of an Appropriate Model Structure

DTIC Science & Technology

1981-11-01

exercise hyperaemic response was greater for a given duration of contraction in water at 34 and 42*C than at lower temperatures. The rate of blood flow...Lambie, D.G. and Johnson, R.H. Ventilatory responses to sustained static forearm exercise in man. New Zealand Med. Journal; 1978, 88(618), 169...KEYWORDS: Static exercise , ventilatory responses . METHODS: Five healthy subjects were used to study the stimulus for hyperventilation which occurs during

Cardiovascular activity in blood-injection-injury phobia during exposure: evidence for diphasic response patterns?

PubMed

Ritz, Thomas; Meuret, Alicia E; Simon, Erica

2013-08-01

Exposure to feared stimuli in blood-injection-injury (BII)-phobia is thought to elicit a diphasic response pattern, with an initial fight-flight-like cardiovascular activation followed by a marked deactivation and possible fainting (vasovagal syncope). However, studies have remained equivocal on the importance of such patterns. We therefore sought to determine the prevalence and clinical relevance of diphasic responses using criteria that require a true diphasic response to exceed cardiovascular activation of an emotional episode of a negative valence and to exceed deactivation of an emotionally neutral episode. Sixty BII-phobia participants and 20 healthy controls were exposed to surgery, anger and neutral films while measuring heart rate, blood pressure, respiratory pattern, and end-tidal partial pressure of carbon dioxide (as indicator of hyperventilation). Diphasic response patterns were observed in up to 20% of BII-phobia participants and 26.6% of healthy controls for individual cardiovascular parameters. BII-phobia participants with diphasic patterns across multiple parameters showed more fear of injections and blood draws, reported the strongest physical symptoms during the surgery film, and showed the strongest tendency to hyperventilate. Thus, although only a minority of individuals with BII phobia shows diphasic responses, their occurrence indicates significant distress. Respiratory training may add to the treatment of BII phobia patients that show diphasic response patterns. Copyright © 2013 Elsevier Ltd. All rights reserved.

Laboratory-induced hyperventilation differentiates female sexual arousal disorder subtypes.

PubMed

Brotto, Lori A; Klein, Carolin; Gorzalka, Boris B

2009-08-01

The effects of heightened sympathetic nervous system (SNS) activity via laboratory-induced hyperventilation (LIH) on subjective and physiological sexual arousal were examined in a heterogeneous group of women with Sexual Arousal Disorder (SAD; n = 60), as well as across subtypes of SAD, in comparison to a control group of women without sexual difficulties (n = 42). Participants took part in 2 min of rapid breathing, a technique previously found to increase SNS activity, immediately prior to viewing erotic stimuli. Physiological arousal (i.e., vaginal pulse amplitude; VPA) was measured via the vaginal photoplethysmograph and subjective arousal was measured via self-report questionnaires. LIH differentiated women with SAD from those in the control group, with LIH increasing VPA in the latter, but having no significant effect in the heterogeneous SAD group. However, among subtypes of SAD, LIH differentiated women with genital (n = 16) and subjective (n = 16) subtypes of SAD from women with combined SAD (n = 28) and women without sexual difficulties. Specifically, women in the control group and those with combined SAD had a significant increase in VPA whereas women with genital or subjective SAD had a significant decrease in VPA following LIH. There was no significant effect of LIH on any self-report measure of sexual arousal following erotic stimuli. Implications of the results for the conceptualization, diagnosis, and treatment of SAD are discussed.

How study of respiratory physiology aided our understanding of abnormal brain function in panic disorder.

PubMed

Sinha, S; Papp, L A; Gorman, J M

2000-12-01

There is a substantial body of literature demonstrating that stimulation of respiration (hyperventilation) is a common event in panic disorder patients during panic attack episodes. Further, a number of abnormalities in respiration, such as enhanced CO2 sensitivity, have been detected in panic patients. This led some to posit that there is a fundamental abnormality in the physiological mechanisms that control breathing in panic disorder and that this abnormality is central to illness etiology. More recently, however, evidence has accumulated suggesting that respiratory physiology is normal in panic patients and that their tendency to hyperventilate and to react with panic to respiratory stimulants like CO2 represents the triggering of a hypersensitive fear network. The fear network anatomy is taken from preclinical studies that have identified the brain pathways that subserve the acquisition and maintenance of conditioned fear. Included are the amygdala and its brain stem projections, the hippocampus, and the medial prefrontal cortex. Although attempts to image this system in patients during panic attacks have been difficult, the theory that the fear network is operative and hyperactive in panic patients explains why both medication and psychosocial therapies are clearly effective. Studies of respiration in panic disorder are an excellent example of the way in which peripheral markers have guided researchers in developing a more complete picture of the neural events that occur in psychopathological states.

Reflex cardioventilatory responses to hypoxia in the flathead gray mullet (Mugil cephalus) and their behavioral modulation by perceived threat of predation and water turbidity.

PubMed

Shingles, A; McKenzie, D J; Claireaux, G; Domenici, P

2005-01-01

In hypoxia, gray mullet surface to ventilate well-oxygenated water in contact with air, an adaptive response known as aquatic surface respiration (ASR). Reflex control of ASR and its behavioral modulation by perceived threat of aerial predation and turbid water were studied on mullet in a partly sheltered aquarium with free surface access. Injections of sodium cyanide (NaCN) into either the bloodstream (internal) or ventilatory water stream (external) revealed that ASR, hypoxic bradycardia, and branchial hyperventilation were stimulated by chemoreceptors sensitive to both systemic and water O2 levels. Sight of a model avian predator elicited bradycardia and hypoventilation, a fear response that inhibited reflex hyperventilation following external NaCN. The time lag to initiation of ASR following NaCN increased, but response intensity (number of events, time at the surface) was unchanged. Mullet, however, modified their behavior to surface under shelter or near the aquarium edges. Turbid water abolished the fear response and effects of the predator on gill ventilation and timing of ASR following external NaCN, presumably because of reduced visibility. However, in turbidity, mullet consistently performed ASR under shelter or near the aquarium edges. These adaptive modulations of ASR behavior would allow mullet to retain advantages of the chemoreflex when threatened by avian predators or when unable to perceive potential threats in turbidity.

Benefits of Manometer in Non-Invasive Ventilatory Support.

PubMed

Lacerda, Rodrigo Silva; de Lima, Fernando Cesar Anastácio; Bastos, Leonardo Pereira; Fardin Vinco, Anderson; Schneider, Felipe Britto Azevedo; Luduvico Coelho, Yves; Fernandes, Heitor Gomes Costa; Bacalhau, João Marcus Ramos; Bermudes, Igor Matheus Simonelli; da Silva, Claudinei Ferreira; da Silva, Luiza Paterlini; Pezato, Rogério

2017-12-01

Introduction Effective ventilation during cardiopulmonary resuscitation (CPR) is essential to reduce morbidity and mortality rates in cardiac arrest. Hyperventilation during CPR reduces the efficiency of compressions and coronary perfusion. Problem How could ventilation in CPR be optimized? The objective of this study was to evaluate non-invasive ventilator support using different devices. The study compares the regularity and intensity of non-invasive ventilation during simulated, conventional CPR and ventilatory support using three distinct ventilation devices: a standard manual resuscitator, with and without airway pressure manometer, and an automatic transport ventilator. Student's t-test was used to evaluate statistical differences between groups. P values <.05 were regarded as significant. Peak inspiratory pressure during ventilatory support and CPR was significantly increased in the group with manual resuscitator without manometer when compared with the manual resuscitator with manometer support (MS) group or automatic ventilator (AV) group. The study recommends for ventilatory support the use of a manual resuscitator equipped with MS or AVs, due to the risk of reduction in coronary perfusion pressure and iatrogenic thoracic injury during hyperventilation found using manual resuscitator without manometer. Lacerda RS , de Lima FCA , Bastos LP , Vinco AF , Schneider FBA , Coelho YL , Fernandes HGC , Bacalhau JMR , Bermudes IMS , da Silva CF , da Silva LP , Pezato R . Benefits of manometer in non-invasive ventilatory support. Prehosp Disaster Med. 2017;32(6):615-620.

Hyperventilation and photic stimulation are useful additions to a placebo-based suggestive seizure induction protocol in patients with psychogenic nonepileptic seizures.

PubMed

Popkirov, Stoyan; Grönheit, Wenke; Wellmer, Jörg

2015-05-01

The early and definitive diagnosis of psychogenic nonepileptic seizures is a common challenge in epileptology practice. Suggestive seizure induction is a valuable tool to aid the differentiation between epileptic and psychogenic nonepileptic seizures, especially when long-term video-EEG monitoring is inconclusive or unavailable. In this retrospective analysis, we compared the diagnostic yield of a classical, placebo-based induction protocol with that of an extended protocol that includes hyperventilation and photic stimulation as means of suggestion while also implementing more open, standardized patient information. We investigated whether the diversification of suggestive seizure induction has an effect on diagnostic yield and whether it preempts the administration of placebo. Data from 52 patients with confirmed psychogenic nonepileptic seizures were analyzed. While suggestive seizure induction using only placebo-based suggestion provoked a typical event in 13 of 20 patients (65%), the extended protocol was positive in 27 of 34 cases (84%); this improvement was not significant (p=0.11). Noninvasive suggestion techniques accounted for 78% of inductions, avoiding placebo administration in a majority of patients. Still, placebo remains an important part of suggestive seizure induction, responsible for 22% (6 out of 27) of successful inductions using our extended protocol. Our study demonstrates that the diversification of suggestive seizure induction is feasible and beneficial for both patients and diagnosticians. Copyright © 2015 Elsevier Inc. All rights reserved.

Liver Injury by Carbon Tetrachloride Intoxication in 16 Patients Treated with Forced Ventilation to Accelerate Toxin Removal via the Lungs: A Clinical Report.

PubMed

Teschke, Rolf

2018-04-27

Carbon tetrachloride (CCl₄) is an efficient but highly toxic solvent, used in households and commercially in the industry under regulatory surveillance to ensure safety at the working place and to protect the workers’ health. However, acute unintentional or intentional intoxications by CCl₄ may rarely occur and are potentially life-threatening. In this review article, therapy options are discussed that are based on a literature review of traditional poisoning cases and the clinical experience with 16 patients with acute poisoning by CCl₄. Among various therapy options, the CO₂-induced hyperventilation therapy will be considered in detail as the most promising approach. This special therapy was developed because only around 1% of the intoxicating CCl₄ is responsible for the liver injury after conversion to toxic radicals via microsomal cytochrome P450 2E1 whereas 99% of the solvent will leave the body unchanged by exhalation. Therefore, to enhance CCl₄ elimination through the lungs, CO₂ is added to the inspiration air at a flow rate of 2⁻3 L min −1 in order to achieve hyperventilation with a respiratory volume of 25⁻30 L min −1 . Under this therapy, the clinical course was favorable in 15/16 patients, corresponding to 93.8%. In essence, patients with acute CCl₄ intoxication should be treated by forced ventilation.

Perioperative management of a child with glutaric aciduria type I undergoing cardiac surgery.

PubMed

Kölker, Stefan; Eichhorn, Joachim; Sebening, Christian; Klein, Berthold; Springer, Wolfgang; Bopp, Christian; Rauch, Helmut

2013-10-01

Patients with glutaric aciduria type I are at risk for acute striatal injury precipitated by catabolic stress. Here, we report the successful interdisciplinary anesthetic and perioperative management of a child with glutaric aciduria type I undergoing cardiac surgery with extracorporeal circulation. Given the central focus on prevention of acute striatal injury, our anesthetic strategy emphasized avoiding a high protein load, high-dose inotropics, especially epinephrine (associated with impaired glucose utilization), deliberate hyperventilation, and other interventions associated with systemic inflammatory response.

AsMA Medical Guidelines for Air Travel: Reported In-Flight Medical Events and Death.

PubMed

Thibeault, Claude; Evans, Anthony D

2015-06-01

Medical Guidelines for Airline Travel provide information that enables healthcare providers to properly advise patients who plan to travel by air. Although there are no publicly available databases providing information on the number of in-flight medical emergencies, the few studies published in the literature indicate that they are uncommon. Minor illnesses such as near-fainting, dizziness, and hyperventilation occur more frequently. However, serious illnesses, such as seizures and myocardial infarction, also occur. In-flight deaths are also rare.

A Stress Test to Evaluate the Physical Capacity of Performing L-1 Anti-G Straining Maneuvers

DTIC Science & Technology

1988-09-01

similar to hyperventilation can produce respiratory alkalosis . Therefore, lowered G-tolerance may result from decreased cerebral blood flow. Another...VE), respiratory exchange ratio (RER) and heart rate (HR were determined for steady state exercise at AGSM duty cyclEs cf 2,, 215%, 33% and 50%. Thesc...V02, ml/kg/min), minute pulmonary ventilation (VE, I/min) and respiratory exchange ratio (RER, VCO 2/VO2) at each duty cycle of discontinuous AGSM

Anxiety Sensitivity, Body Vigilance, Interoceptive Acuity, and Cardiovascular Reactivity in the Genesis of Panic

DTIC Science & Technology

2000-08-04

hyperventilation in nonclinical subjects. Journal of Abnormal PsycholoBY. 103.693-699. Rapee, R.M., Brown, T.A., Antony, M.M, and Barlow , D.H. (1992). Response to...of Medical and Clinical Psychology Master of Science 1000 Thesis and Abstract Approved: ~\\’JJ~~ Michael Feuerstein, Ph.D. Department of Medical and...Clinical Psychology Thesis Advisor David Krantz, Ph.D. Department of Medical and CUnical Psychology Committee Member ~~.~\\?J>----- Department of

Effects of Attentional Focus on Emotional Responding to a Biological Challenge in Panic Disorder

DTIC Science & Technology

1996-08-26

Panic .5 1.4. Biological Challenges 6 1.4.1. Carbon dioxide 6 1.4.2. Sodium Lactate 7 1.4.3. Yohimbine 7 1.4.4. Caffeine 8 1.4.5. Hyperventilation 8...biological challenges (e.g., carbon dioxide, caffeine , lactate infusion) have been used to provoke somatic symptoms that are similar to those reported during...challenges utilized in the study of panic disorder. Examples of biological challenge agents include carbon dioxide, sodium lactate, yohimbine, caffeine

[Intravenous ethyl alcohol in metabolic resuscitation].

PubMed

Agolini, G; Lipartiti, T; Zaffiri, O; Musso, L; Belloni, G P

1980-11-01

Intravenously administered ethyl alcohol may be effective as analgesic and hypotensive peripheric vasoactive drug. In the Intensive Care Departments parenteral ethanol administration is infrequent because no "sure dosage" can be suggested in adults and children. Liver, kidney and C.N.S. diseases can worsen; foetopathy can follow. Drug-ethanol interaction may be particularly important for some patients admitted in Intensive Care Departments. Often the potential caloric support cannot be fully utilized ("empty" calories) and seldom hyperventilation, hyperlactacidemia and impaired protein synthesis can follow.

Histone Modifications in a Mouse Model of Early Adversities and Panic Disorder: Role for Asic1 and Neurodevelopmental Genes.

PubMed

Cittaro, Davide; Lampis, Valentina; Luchetti, Alessandra; Coccurello, Roberto; Guffanti, Alessandro; Felsani, Armando; Moles, Anna; Stupka, Elia; D' Amato, Francesca R; Battaglia, Marco

2016-04-28

Hyperventilation following transient, CO2-induced acidosis is ubiquitous in mammals and heritable. In humans, respiratory and emotional hypersensitivity to CO2 marks separation anxiety and panic disorders, and is enhanced by early-life adversities. Mice exposed to the repeated cross-fostering paradigm (RCF) of interference with maternal environment show heightened separation anxiety and hyperventilation to 6% CO2-enriched air. Gene-environment interactions affect CO2 hypersensitivity in both humans and mice. We therefore hypothesised that epigenetic modifications and increased expression of genes involved in pH-detection could explain these relationships. Medullae oblongata of RCF- and normally-reared female outbred mice were assessed by ChIP-seq for H3Ac, H3K4me3, H3K27me3 histone modifications, and by SAGE for differential gene expression. Integration of multiple experiments by network analysis revealed an active component of 148 genes pointing to the mTOR signalling pathway and nociception. Among these genes, Asic1 showed heightened mRNA expression, coherent with RCF-mice's respiratory hypersensitivity to CO2 and altered nociception. Functional enrichment and mRNA transcript analyses yielded a consistent picture of enhancement for several genes affecting chemoception, neurodevelopment, and emotionality. Particularly, results with Asic1 support recent human findings with panic and CO2 responses, and provide new perspectives on how early adversities and genes interplay to affect key components of panic and related disorders.

Voluntary respiratory control and cerebral blood flow velocity upon ice-water immersion.

PubMed

Mantoni, Teit; Rasmussen, Jakob Højlund; Belhage, Bo; Pott, Frank Christian

2008-08-01

In non-habituated subjects, cold-shock response to cold-water immersion causes rapid reduction in cerebral blood flow velocity (approximately 50%) due to hyperventilation, increasing risk of syncope, aspiration, and drowning. Adaptation to the response is possible, but requires several cold immersions. This study examines whether thorough instruction enables non-habituated persons to attenuate the ventilatory component of cold-shock response. There were nine volunteers (four women) who were lowered into a 0 degrees C immersion tank for 60 s. Middle cerebral artery mean velocity (CBFV) was measured together with ventilatory parameters and heart rate before, during, and after immersion. Within seconds after immersion in ice-water, heart rate increased significantly from 95 +/- 8 to 126 +/- 7 bpm (mean +/- SEM). Immersion was associated with an elevation in respiratory rate (from 12 +/- 3 to 21 +/- 5 breaths, min(-1)) and tidal volume (1022 +/- 142 to 1992 +/- 253 ml). Though end-tidal carbon dioxide tension decreased from 4.9 +/- 0.13 to 3.9 +/- 0.21 kPa, CBFV was insignificantly reduced by 7 +/- 4% during immersion with a brief nadir of 21 +/- 4%. Even without prior cold-water experience, subjects were able to suppress reflex hyperventilation following ice-water immersion, maintaining the cerebral blood flow velocity at a level not associated with impaired consciousness. This study implies that those susceptible to accidental cold-water immersion could benefit from education in cold-shock response and the possibility of reducing the ventilatory response voluntarily.

Respiratory manifestations of panic disorder: causes, consequences and therapeutic implications.

PubMed

Sardinha, Aline; Freire, Rafael Christophe da Rocha; Zin, Walter Araújo; Nardi, Antonio Egidio

2009-07-01

Multiple respiratory abnormalities can be found in anxiety disorders, especially in panic disorder (PD). Individuals with PD experience unexpected panic attacks, characterized by anxiety and fear, resulting in a number of autonomic and respiratory symptoms. Respiratory stimulation is a common event during panic attacks. The respiratory abnormality most often reported in PD patients is increased CO2 sensitivity, which has given rise to the hypothesis of fundamental abnormalities in the physiological mechanisms that control breathing in PD. There is evidence that PD patients with dominant respiratory symptoms are more sensitive to respiratory tests than are those who do not manifest such symptoms, and that the former group constitutes a distinct subtype. Patients with PD tend to hyperventilate and to panic in response to respiratory stimulants such as CO2, triggering the activation of a hypersensitive fear network. Although respiratory physiology seems to remain normal in these subjects, recent evidence supports the idea that they present subclinical abnormalities in respiration and in other functions related to body homeostasis. The fear network, composed of the hippocampus, the medial prefrontal cortex, the amygdala and its brain stem projections, might be oversensitive in PD patients. This theory might explain why medication and cognitive-behavioral therapy are both clearly effective. Our aim was to review the relationship between respiration and PD, addressing the respiratory subtype of PD and the hyperventilation syndrome, with a focus on respiratory challenge tests, as well as on the current mechanistic concepts and the pharmacological implications of this relationship.

Relationship of 133Xe cerebral blood flow to middle cerebral arterial flow velocity in men at rest

NASA Technical Reports Server (NTRS)

Clark, J. M.; Skolnick, B. E.; Gelfand, R.; Farber, R. E.; Stierheim, M.; Stevens, W. C.; Beck, G. Jr; Lambertsen, C. J.

1996-01-01

Cerebral blood flow (CBF) was measured by 133Xe clearance simultaneously with the velocity of blood flow through the left middle cerebral artery (MCA) over a wide range of arterial PCO2 in eight normal men. Average arterial PCO2, which was varied by giving 4% and 6% CO2 in O2 and by controlled hyperventilation on O2, ranged from 25.3 to 49.9 mm Hg. Corresponding average values of global CBF15 were 27.2 and 65.0 ml 100 g min-1, respectively, whereas MCA blood-flow velocity ranged from 42.8 to 94.2 cm/s. The relationship of CBF to MCA blood-flow velocity over the imposed range of arterial PCO2 was described analytically by a parabola with the equation: CBF = 22.8 - 0.17 x velocity + 0.006 x velocity2 The observed data indicate that MCA blood-flow velocity is a useful index of CBF response to change in arterial PCO2 during O2 breathing at rest. With respect to baseline values measured while breathing 100% O2 spontaneously, percent changes in velocity were significantly smaller than corresponding percent changes in CBF at increased levels of arterial PCO2 and larger than CBF changes at the lower arterial PCO2. These observed relative changes are consistent with MCA vasodilation at the site of measurement during exposure to progressive hypercapnia and also during extreme hyperventilation hypocapnia.

Exaggerated compensatory response to acute respiratory alkalosis in panic disorder is induced by increased lactic acid production.

PubMed

Ueda, Yoshiyasu; Aizawa, Masayo; Takahashi, Atsushi; Fujii, Masamitsu; Isaka, Yoshitaka

2009-03-01

In acute respiratory alkalosis, the severity of alkalaemia is ameliorated by a decrease in plasma [HCO(3)(-)] of 0.2 mEq/L for each 1 mmHg decrease in PaCO(2). Although hyperventilation in panic disorder patients is frequently encountered in outpatients, the drop in plasma [HCO(3)(-)] sometimes surpasses the expectation calculated from the above formula. The quantitative relationship between reduced PaCO(2) and plasma [HCO(3)(-)] in acute respiratory alkalosis has not been studied in panic disorder patients. Our objective was to provide reference data for the compensatory metabolic changes in acute respiratory alkalosis in panic disorder patients. In 34 panic disorder patients with hyperventilation attacks, we measured arterial pH, PaCO(2), plasma [HCO(3)(-)] and lactate on arrival at the emergency room. For each decrease of 1 mmHg in PaCO(2), plasma [HCO(3)(-)] decreased by 0.41 mEq/L. During hypocapnia, panic disorder patients exhibited larger increases in serum lactate levels (mean +/- SD; 2.59 +/- 1.50 mmol/L, range; 0.78-7.78 mmol/L) than previously reported in non-panic disorder subjects. Plasma lactate accumulation was correlated with PaCO(2) (P < 0.001). These results suggest that the compensatory metabolic response to acute respiratory alkalosis is exaggerated by increased lactic acid production in panic disorder patients. Here, we call attention to the diagnosis of acid-base derangements by means of plasma [HCO(3)(-)] and lactate concentration in panic disorder patients.

Purinergic and adenosine receptors contribute to hypoxic hyperventilation in zebrafish (Danio rerio).

PubMed

Coe, Alisha J; Picard, Alexina J; Jonz, Michael G

2017-12-01

The chemoreceptors involved in oxygen sensing in teleost fish are neuroepithelial cells (NECs) in the gills, and are analogous to glomus cells in the mammalian carotid body. Purinergic signalling mechanisms involving the neurotransmitters, ATP and adenosine, have been identified in mediating hypoxic signalling in the carotid body, but these pathways are not well understood in the fish gill. The present study used a behavioural assay to screen for the effects of drugs, that target purinergic and adenosine receptors, on the hyperventilatory response to hypoxia in larval zebrafish (Danio rerio) in order to determine if the receptors on which these drugs act may be involved in hypoxic signalling. The purinergic receptor antagonist, PPADS, targets purinergic P2X2/3 receptors and inhibited the hyperventilatory response to hypoxia (IC 50 =18.9μM). The broad-spectrum purinergic agonist, ATPγS, elicited a hyperventilatory response (EC 50 =168μM). The non-specific adenosine receptor antagonist, caffeine, inhibited the hyperventilatory response to hypoxia, as did the specific A2a receptor antagonist, SCH58261 (IC 50 =220nM). These results suggest that P2X2/3 and A2a receptors are candidates for mediating hypoxic hyperventilation in zebrafish. This study highlights the potential of applying chemical screening to ventilatory behaviour in zebrafish to further our understanding of the pathways involved in signalling by gill NECs and oxygen sensing in vertebrates. Copyright © 2017 Elsevier Inc. All rights reserved.

Eucapnic voluntary hyperventilation in diagnosing exercise-induced laryngeal obstructions.

PubMed

Christensen, Pernille M; Rasmussen, Niels

2013-11-01

Exercise-induced laryngeal obstructions (EILOs) cause exercise-related respiratory symptoms (ERRS) and are important differential diagnoses to exercise-induced asthma. The diagnostic method for EILOs includes provocation to induce the obstruction followed by a verification of the obstruction and the degree thereof. The objective of the present study was to examine if a eucapnic voluntary hyperventilation (EVH) test could induce laryngeal obstructions laryngoscopically identical in subtypes and development as seen during an exercise test. EVH and exercise testing with continuous laryngoscopy were performed during a screening of two national athletic teams (n = 67). The laryngoscopic recordings were examined for usability, abnormalities and maximal supraglottic and glottic obstruction using two currently available methods (Eilomea and CLE-score). The participants were asked questions on ERRS, and whether the symptoms experienced during each provocation matched those experienced during regular training. A total of 39 completed both tests. There were no significant differences in subtypes and development thereof, the experience of symptoms, and specificity and sensitivity between the methods. Significantly more recordings obtained during the exercise test were usable for evaluation primarily due to resilient mucus on the tip of the fiber-laryngoscope in the EVH test. Only recordings of six athletes from both provocation methods were usable for evaluation using the Eilomea method (high-quality demand). Amongst these, a linear correlation was found for the glottic obstruction. EVH tests can induce EILOs. However, the present test protocol needs adjustments to secure better visualisation of the larynx during provocation.

Hyperventilation in asthma: a validation study of the Nijmegen Questionnaire--NQ.

PubMed

Grammatopoulou, Eirini P; Skordilis, Emmanouil K; Georgoudis, Georgios; Haniotou, Aikaterini; Evangelodimou, Afroditi; Fildissis, George; Katsoulas, Theodoros; Kalagiakos, Panagiotis

2014-10-01

The Nijmegen questionnaire (NQ) has previously been used for screening the hyperventilation syndrome (HVS) in asthmatics. However, no validity study has been reported so far. To examine the validity and reliability of the NQ in asthma patients and identify the prevalence of HVS. The NQ (n = 162) was examined for translation, construct, cross-sectional and discriminant validity as well as for internal consistency and test-retest reliability. Principal component analysis and exploratory factor analysis revealed a single factor solution with 11 items and 58.6% of explained variability. These 11 NQ items showed high internal consistency (Cronbach's alpha = 0.92) and test-retest reliability (IR = 0.98). Higher NQ scores were found in the following subgroups: women versus men (p < 0.01); participants with moderate versus mild asthma (p < 0.001) or uncontrolled versus controlled asthma (p < 0.001), and participants with breath-hold time (BHT) < 30 versus ≥ 30 s (p < 0.01) or end-tidal CO2 (ETCO2) ≤ 35 versus >35 mmHg (p < 0.001). A cut-off score of >17 discriminated the participants with regard to the presence of HVS. The NQ showed 92.73% sensitivity and 91.59% specificity. The total NQ score was found significantly correlated with ETCO2 (r = -0.68), RR (r = 0.66) and BHT (r = -0.65). The prevalence of HVS was found 34%. The NQ is a valid and reliable questionnaire for screening HVS in patients with stable mild-to-moderate asthma.

Anesthetic considerations for patients with esophageal achalasia undergoing peroral endoscopic myotomy: a retrospective case series review.

PubMed

Löser, Benjamin; Werner, Yuki B; Punke, Mark A; Saugel, Bernd; Haas, Sebastian; Reuter, Daniel A; Mann, Oliver; Duprée, Anna; Schachschal, Guido; Rösch, Thomas; Petzoldt, Martin

2017-05-01

Peroral endoscopic myotomy (POEM) is a novel technique for treating esophageal achalasia. During POEM, carbon dioxide (CO 2 ) is insufflated to aid surgical dissection, but it may inadvertently track into surrounding tissues, causing systemic CO 2 uptake and tension capnoperitoneum. This in turn may affect cardiorespiratory function. This study quantified these cardiorespiratory effects and treatment by hyperventilation and percutaneous abdominal needle decompression (PND). One hundred and seventy-three consecutive patients who underwent POEM were included in this four-year retrospective study. Procedure-related changes in peak inspiratory pressure (p max ), end-tidal CO 2 levels (etCO 2 ), minute ventilation (MV), mean arterial pressure (MAP), and heart rate (HR) were analyzed. We also quantified the impact of PND on these cardiorespiratory parameters. During the endoscopic procedure, cardiorespiratory parameters increased from baseline: p max 15.1 (4.5) vs 19.8 (4.7) cm H 2 O; etCO 2 4.5 (0.4) vs 5.5 (0.9) kPa [34.0 (2.9) vs 41.6 (6.9) mmHg]; MAP 73.9 (9.7) vs 99.3 (15.2) mmHg; HR 67.6 (12.4) vs 85.3 (16.4) min -1 (P < 0.001 for each). Hyperventilation [MV 5.9 (1.2) vs 9.0 (1.8) L·min -1 , P < 0.001] was applied to counteract iatrogenic hypercapnia. Individuals with tension capnoperitoneum treated with PND (n = 55) had higher peak p max values [22.8 (5.7) vs 18.4 (3.3) cm H 2 O, P < 0.001] than patients who did not require PND. After PND, p max [22.8 (5.7) vs 19.9 (4.3) cm H 2 O, P = 0.045] and MAP [98.2 (16.3) vs 88.6 (11.8) mmHg, P = 0.013] decreased. Adverse events included pneumothorax (n = 1), transient myocardial ischemia (n = 1), and subcutaneous emphysema (n = 49). The latter precluded immediate extubation in eight cases. Postanesthesia care unit (PACU) stay was longer in individuals with subcutaneous emphysema than in those without [74.9 min (34.5) vs 61.5 (26.8 min), P = 0.007]. Carbon dioxide insufflation during POEM produces systemic CO 2 uptake and increased intra-abdominal pressure. Changes in cardiorespiratory parameters include increased p max , etCO 2 , MAP, and HR. Hyperventilation and PND help mitigate some of these changes. Subcutaneous emphysema is common and may delay extubation and prolong PACU stay.

Breathing metabolic simulator.

NASA Technical Reports Server (NTRS)

Bartlett, R. G., Jr.; Hendricks, C. M.; Morison, W. B.

1971-01-01

Description of a device for simulation of the human breathing and metabolic parameters required for the evaluation of respiratory diagnostic, monitoring, support and resuscitation equipment. The remotely controlled device allows wide variations in breathing rate and depth, breath velocity contour, oxygen uptake and carbon dioxide release to simulate conditions from sleep to hard work, with respiration exchange ratios ranging from hypoventilation to hyperventilation. It also reduces the cost of prolonged testing when simulation chambers with human subjects require three shifts of crews and standby physicians. Several block diagrams of the device and subsystems are given.

Genesis of multipeaked waves of the esophagus: repetitive contractions or motion artifact?

PubMed

Sampath, Neha J; Bhargava, Valmik; Mittal, Ravinder K

2010-06-01

Multipeaked waves (MPW) in the distal esophagus occur frequently in patients with esophageal spastic motor disorders and diabetes mellitus and are thought to represent repetitive esophageal contractions. We aimed to investigate whether the relative motion between a stationary pressure sensor and contracted peristaltic esophageal segment that moves with respiration leads to the formation of MPW. We mathematically modeled the effect of relative movement between a moving pressure segment and a fixed pressure sensor on the pressure waveform morphology. We conducted retrospective analysis of 100 swallow-induced esophageal contractions in 10 patients, who demonstrated >30% MPW on high-resolution manometry (HRM) during standardized swallows. Finally, using HRM, we determined the effects of suspended breathing and hyperventilation on the waveform morphology in 10 patients prospectively. Modeling revealed that relative movement between a stationary pressure sensor and a moving contracted segment, contraction duration, contraction amplitude, respiratory frequency, and depth of respiration affects the waveform morphology. Retrospective analysis demonstrated a close temporal association with the onset of second and subsequent contractions in MPW with respiratory phase reversals. Numbers of peaks in MPW and respiratory phase reversals were closely related to the duration of contraction. In the prospective study, suspended breathing and hyperventilation resulted in a significant decrease and increase in the MPW frequency as well as the number of peaks within MPW respectively. We conclude that MPW observed during clinical motility studies are not indicative of repetitive esophageal contraction; rather they represent respiration-related movement of the contracted esophageal segment in relation to the stationary pressure sensor.

Dynamic hyperinflation after metronome-paced hyperventilation in COPD--a 2 year follow-up.

PubMed

Hannink, Jorien; Lahaije, Anke; Bischoff, Erik; van Helvoort, Hanneke; Dekhuijzen, Richard; Schermer, Tjard; Heijdra, Yvonne

2010-11-01

In contrast to the decline in FEV(1), the behavior of dynamic hyperinflation (DH) over time is unknown in patients with COPD. Metronome-paced hyperventilation (MPH) is a simple applicable surrogate for exercise to detect DH. To evaluate changes in MPH-induced DH during two years follow-up in mild-to-severe COPD patients. Additionally, influence of smoking status on DH and the relation between DH and other lung function parameters were assessed. Patients were recruited from a randomized controlled trial conducted in general practice. Measurements of lung function and DH were performed at baseline and after 12 and 24 months. DH was assessed by MPH with breathing frequency set at twice the baseline rate. Change in inspiratory capacity after MPH was used to reflect change in end-expiratory lung volume and therefore DH, presuming constant total lung capacity. During follow-up, 68 patients completed all measurements. DH increased by 0.23±0.06L (p≤0.001). No significant changes in FEV(1) %pred were seen. Smokers had lower FEV(1) and a more rapid decline than non-smokers. DH in smokers increased more over time compared to non-smokers. The amount of DH correlated positively with resting inspiratory capacity. After two years, a significant increase in MPH-induced DH in COPD patients was demonstrated, which was not accompanied by a decline in FEV(1). It might be that DH is a sensitive measure to track consequences of changes in airflow obstruction. Copyright © 2010 Elsevier Ltd. All rights reserved.

Respiratory and sleep disorders in female children with atypical Rett syndrome caused by mutations in the CDKL5 gene.

PubMed

Hagebeuk, Eveline E O; van den Bossche, Renilde A S; de Weerd, Al W

2013-05-01

In female children with drug-resistant seizures and developmental delay from birth, atypical Rett syndrome caused by mutations in the CDKL5 gene should be considered. Several clinical features resemble classic Rett syndrome. Respiratory and sleep abnormalities are frequently present in Rett syndrome, whereas little is known in patients with CDKL5 mutations. In four genetically confirmed female patients with CDKL5 mutations (age range 2-15 y), the presence of breathing and sleep abnormalities was evaluated using the validated Sleep Disturbance Scale for Children and polysomnography (PSG). The Sleep Disturbance Scale for Children indicated disorders of initiating and maintaining sleep, daytime somnolence, and sleep breathing disorders. In one patient, PSG showed central apnoeas during sleep: her total apnoea-hypopnoea index (AHI) was 4.9, of which the central AHI was 3.4/h. When awake, central apnoeas were present in two of the four female children (central AHI 28/h and 41/h respectively), all preceded by hyperventilation. PSG showed low rapid eye movement (REM) sleep (9.7-18.3%), frequent awakenings, and low sleep efficiency (range 59-78%). Episodic hyperventilation followed by central apnoeas was present while awake in two of four patients. This may indicate failure of brainstem respiratory centres. In addition, low REM sleep, frequent arousals (not caused by apnoeas/seizures), and low sleep efficiency were present. Similar to Rett syndrome, in patients with CDKL5 mutations PSG seems warranted to evaluate breathing and sleep disturbances. © The Authors. Developmental Medicine & Child Neurology © 2012 Mac Keith Press.

Bronchial hyperresponsiveness testing in athletes of the Swiss Paralympic team

PubMed Central

2013-01-01

Background The aim of this study was to assess airway hyperresponsiveness to eucapnic voluntary hyperventilation and dry powder mannitol challenge in athletes aiming to participate at the Paralympic Games 2008 in Beijing, especially in athletes with spinal cord injury. Methods Forty-four athletes with a disability (27 with paraplegia (group 1), 3 with tetraplegia (group 2) and 14 with other disabilities such as blindness or single limb amputations (group 3) performed spirometry, skin prick testing, measurement of exhaled nitric oxide, eucapnic voluntary hyperventilation challenge test (EVH) and mannitol challenge test (MCT). A fall in FEV1 of ≥10% in either challenge test was deemed positive for exercise-induced bronchoconstriction. Results Fourteen (32%) athletes were atopic and 7 (16%) had a history of physician-diagnosed asthma. Absolute lung function values were significantly lower in patients of group 1 and 2 compared to group 3. Nine (20%) athletes were positive to EVH (8 paraplegics, 1 tetraplegic), and 8 (18%) athletes were positive to MCT (7 paraplegics, 1 tetraplegic). Fourteen (22.7%) subjects were positive to at least one challenge; only three athletes were positive to both tests. None of the athletes in group 3 had a positive test. Both challenge tests showed a significant association with physician-diagnosed asthma status (p = 0.0001). The positive and negative predictive value to diagnose physician-diagnosed asthma was 89% and 91% for EHV, and 75% and 86% for MCT, respectively. Conclusion EVH and MCT can be used to identify, but especially exclude asthma in Paralympic athletes. PMID:23845126

Anesthetic management of neurosurgical procedures during pregnancy: a case series.

PubMed

Kazemi, Pooya; Villar, Giselle; Flexman, Alana M

2014-07-01

Neurosurgical disorders are rare during pregnancy and challenge the anesthesiologist with conflicting anesthetic considerations and little evidence to guide decision-making. Our objective was to review the anesthetic management of pregnant patients undergoing intracranial neurosurgery at our institution and to describe the perioperative complications and outcomes. We used our institutional Discharge Abstract Database to identify patients assigned both neurological and obstetrical International Classification of Disease 10-A codes between April 1, 2001 and March 1, 2012. Pregnant patients who underwent intracranial neurosurgical procedures underwent a detailed chart review to extract demographic data and details about their anesthetic management and outcome. Nine patients underwent full chart review with a median age of 28 (range, 17 to 35) years and a gestational age of 23 (range, 7 to 30) weeks. Patients underwent a craniotomy for vascular lesions (4), neoplasms (3), and traumatic brain injuries (2). One patient was hyperventilated (PaCO2 28 mmHg), and mannitol and furosemide were used in 6 and 3 patients, respectively, without complication. Maternal neurological outcomes were good in 5 patients (Glasgow Outcome Scale of >3), poor in 3 patients (Glasgow Outcome Scale 3), and 1 patient died. Fetal outcomes were good in 5 patients and poor in 4 patients (1 therapeutic abortion, 3 intrauterine fetal demises). All cases of fetal distress or demise were either remote or occurred before the anesthetic management. Pregnant patients undergoing neurosurgery experience a high rate of morbidity and mortality. There were no adverse outcomes directly attributed to the use of osmotic diuretics and hyperventilation in our series.

[Instrumentation support in respiratory kinesiotherapy].

PubMed

Vandevenne, A; Sergysels, R; Ravez, P; Worth, H; De Coster, A

1988-01-01

The points of impact of instrumental support in respiratory physiotherapy are numerous; they concern primarily the pulmonary expansion, bronchial drainage and function of respiratory muscles. The pulmonary expansion may be helped by incitant spirometry and either intermittent or continuous positive pressure respiration, or indirectly by the utilisation of respiration against resistance (expiratory bottles, masks with uni-directional valves and expiratory resistances etc.). These different techniques may be used in the presence of instability of the respiratory units, secondary to an alteration of surfactant or to closure of the small airways induced by a transitory reduction (in the post-operative period) or permanent reduction (such as parietal wall disease of mechanical or neuro-muscular origin) of the functional residual capacity (CRF). If the continuous positive airway pressure (CPAP) seems particularly helpful for the CRF to recover to the pre-operative level it also appears on the contrary as the least efficacious technique to increase trans-pulmonary pressure. The instrumental support for bronchial drainage may theoretically affect the tension activity of the transport (instrumental help in the pulmonary expansion and in hyperventilation), muco-ciliary transport (external parietal vibration or internal vibrations applied to the upper airways), the biphasic flow (expiratory assistance by negative pressure and humidifiers). The function of the respiratory muscles may in certain cases be improved by the use of abdominal pneumatic cuirasses, by hyperventilation exercises in an isocapnoeic milieu or in breathing exercises against an additional inspiratory or expiratory resistance. If the physiological foundation of mechanical support in respiratory education may be frequently identified, the clinical results reported in the literature are often contradictory.

Respiratory acidosis prolongs, while alkalosis shortens, the duration and recovery time of vecuronium in humans.

PubMed

Yamauchi, Masanori; Takahashi, Hiromi; Iwasaki, Hiroshi; Namiki, Akiyoshi

2002-03-01

To determine the effects of respiratory acidosis and alkalosis by mechanical ventilation on the onset, duration, and recovery times of vecuronium. Randomized, prospective study. Operating rooms in the Sapporo Medical University Hospital and Kitami Red Cross Hospital. 90 ASA physical status I and II patients undergoing lower abdominal surgery. Patients were randomly allocated to one of three groups by arterial carbon dioxide tension level (PaCO2; mmHg) after induction: hyperventilation group (PaCO2 = 25-35), normoventilation group (PaCO2 = 35-45), and hypoventilation group (PaCO2 = 45-55). Anesthesia was maintained by spinal block with inhalation of 50% to 66% nitrous oxide in oxygen and intermittent intravenous administration of fentanyl and midazolam with tracheal intubation. After vecuronium 0.08 mg/kg was given, onset, duration, and recovery time were measured by mechanomyography (Biometer Myograph 2,000, Odense, Denmark). There were significant differences in the duration and recovery time of vecuronium among the normoventilation group (12.7 +/- 3.3 min and 11.8 +/- 2.8 min, respectively), the hyperventilation group (10.6 +/- 3.5 min and 9.2 +/- 2.7 min, respectively; p < 0.01), and the hypoventilation group (14.4 +/- 3.1 min and 15.0 +/- 3.7 min, respectively; p < 0.01) (mean SD). The closest significant correlation in this study was observed between recovery time and arterial blood pH (r = 0.57; p < 0.05). In humans, duration and recovery times of vecuronium are prolonged in respiratory acidosis and shortened in respiratory alkalosis.

Measuring Cerebral Hypoperfusion Induced by Hyperventilation Challenge With Intravoxel Incoherent Motion Magnetic Resonance Imaging in Healthy Volunteers.

PubMed

Pavilla, Aude; Arrigo, Alessandro; Mejdoubi, Mehdi; Duvauferrier, Régis; Gambarota, Giulio; Saint-Jalmes, Hervé

The aim of this study was to demonstrate the feasibility to assess cerebral hypoperfusion with a hyperventilation (HV) challenge protocol using intravoxel incoherent motion (IVIM) magnetic resonance imaging. Magnetic resonance imaging experiments were performed on 10 healthy volunteers at 1.5 T, with a diffusion IVIM magnetic resonance imaging protocol using a set of b-values optimized by Cramer-Rao Lower Bound analysis. Hypoperfusion was induced by an HV maneuver. Measurements were performed in normoventilation and HV conditions. Biexponential curve fitting was used to obtain the perfusion fraction (f), pseudodiffusion coefficient (D*), and the product fD* in gray matter (GM) regions of interest (ROIs). Regional cerebral blood flow in the same ROIs was also assessed with arterial spin labeling. The HV challenge led to a diminution of IVIM perfusion-related parameters, with a decrease of f and fD* in the cerebellum (P = 0.03 for f; P = 0.01 for fD*), thalamus GM (P = 0.09 for f; P = 0.01 for fD*), and lenticular nuclei (P = 0.03 for f; P = 0.02 for fD*). Mean GM cerebral blood flow (in mL/100 g tissue/min) measured with arterial spin labeling averaged over all ROIs also decreased (normoventilation: 42.7 ± 4.1 vs HV: 33.2 ± 2.2, P = 0.004) during the HV challenge. The optimized IVIM protocol proposed in the current study allows for measurements of cerebral hypoperfusion that might be of great interest for pathologies diagnosis such as ischemic stroke.

Hyperventilation syndrome in adolescents with and without asthma.

PubMed

D'Alba, Irene; Carloni, Ines; Ferrante, Anna Lisa; Gesuita, Rosaria; Palazzi, Maria Laura; de Benedictis, Fernando Maria

2015-12-01

Data on the prevalence of hyperventilation syndrome (HVS) in adolescents are scanty. To determine the prevalence of HVS in a population of adolescents with and without asthma, and to verify whether HVS was related to asthma activity. A population of adolescents was asked to self-complete a questionnaire, including the Nijmegen questionnaire to assess HVS, and a standardized asthma questionnaire. Seven hundred and sixty questionnaires were suitable for analysis. One hundred and twenty subjects (15.8%) were classified as asthmatic. Forty-seven subjects (6.2%) had a Nijmegen score ≥ 23, which was suggestive of HVS. Symptoms indicative of HVS were ten times more common in subjects with asthma (25%) than in those without asthma (2.5%). Nijmegen score was significantly higher in subjects with lifetime asthma (P < 0.001), current episodic asthma (P < 0.05) and current active asthma (P < 0.001) than in those with no asthma. In the whole population, girls presented HVS more frequently than boys (P < 0.001). There was a significant effect of gender (females, OR 3.2) and status of asthma (lifetime asthma, OR 11.2; current episodic asthma, OR 8.9; current active asthma, OR 41.5) on the probability of suffering from HVS. The prevalence of symptoms indicative of HVS in an unselected population of adolescents was relatively high. Symptoms were more common in girls and in subjects with asthma, and there was a significant effect of asthma activity on the probability of suffering from HVS. Further studies need to be performed in order to validate a screening tool for HVS in both adolescents and asthmatic subjects. © 2014 Wiley Periodicals, Inc.

Influence of chest compression artefact on capnogram-based ventilation detection during out-of-hospital cardiopulmonary resuscitation.

PubMed

Leturiondo, Mikel; Ruiz de Gauna, Sofía; Ruiz, Jesus M; Julio Gutiérrez, J; Leturiondo, Luis A; González-Otero, Digna M; Russell, James K; Zive, Dana; Daya, Mohamud

2018-03-01

Capnography has been proposed as a method for monitoring the ventilation rate during cardiopulmonary resuscitation (CPR). A high incidence (above 70%) of capnograms distorted by chest compression induced oscillations has been previously reported in out-of-hospital (OOH) CPR. The aim of the study was to better characterize the chest compression artefact and to evaluate its influence on the performance of a capnogram-based ventilation detector during OOH CPR. Data from the MRx monitor-defibrillator were extracted from OOH cardiac arrest episodes. For each episode, presence of chest compression artefact was annotated in the capnogram. Concurrent compression depth and transthoracic impedance signals were used to identify chest compressions and to annotate ventilations, respectively. We designed a capnogram-based ventilation detection algorithm and tested its performance with clean and distorted episodes. Data were collected from 232 episodes comprising 52 654 ventilations, with a mean (±SD) of 227 (±118) per episode. Overall, 42% of the capnograms were distorted. Presence of chest compression artefact degraded algorithm performance in terms of ventilation detection, estimation of ventilation rate, and the ability to detect hyperventilation. Capnogram-based ventilation detection during CPR using our algorithm was compromised by the presence of chest compression artefact. In particular, artefact spanning from the plateau to the baseline strongly degraded ventilation detection, and caused a high number of false hyperventilation alarms. Further research is needed to reduce the impact of chest compression artefact on capnographic ventilation monitoring. Copyright © 2017 Elsevier B.V. All rights reserved.

Acute respiratory alkalosis occurring after endoscopic third ventriculostomy -A case report-.

PubMed

Sung, Hui-Jin; Sohn, Ju-Tae; Kim, Jae-Gak; Shin, Il-Woo; Ok, Seong-Ho; Lee, Heon-Keun; Chung, Young-Kyun

2010-12-01

An endoscopic third ventriculostomy was performed in a 55-year-old man with an obstructive hydrocephalus due to aqueductal stenosis. The vital signs and laboratory studies upon admission were within the normal limits. Anesthesia was maintained with nitrous oxide in oxygen and 6% desflurane. The patient received irrigation with approximately 3,000 ml normal saline during the procedure. Anesthesia and operation were uneventful. However, he developed postoperative hyperventilation in the recovery room, and arterial blood gas analysis revealed acute respiratory alkalosis. We report a rare respiratory alkalosis that occurred after an endoscopic third ventriculostomy.

Adverse Reactions in Allogeneic Blood Donors: A Tertiary Care Experience from a Developing Country.

PubMed

Sultan, Sadia; Baig, Mohammad Amjad; Irfan, Syed Mohammed; Ahmed, Syed Ijlal; Hasan, Syeda Faiza

2016-03-01

Fragmented blood transfusion services along with an unmotivated blood donation culture often leads to blood shortage. Donor retention is crucial to meet the increasing blood demand, and adverse donor reactions have a negative impact on donor return. The aim of this study was to estimate adverse donor reactions and identify any demographic association.  . We conducted a prospective study between January 2011 and December 2013. A total of 41,759 healthy donors were enrolled. Professionally trained donor attendants drew blood and all donors were observed during and following donation for possible adverse events for 20 minutes. Blood donors were asked to report if they suffered from any delayed adverse consequences.  . Out of 41,759 blood donors, 537 (1.3%) experienced adverse reactions. The incidence was one in every 78 donations. The mean age of donors who experienced adverse events was 26.0±6.8 years, and all were male. Out of 537 donors, 429 (80%) developed vasovagal reaction (VVR), 133 (25%) had nausea, 63 (12%) fainted, 35 (6%) developed hyperventilation, 9 (2%) had delayed syncope, and 9 (2%) developed hematoma. Arterial prick, nerve injury, cardiac arrest, and seizures were not observed. Donors aged less than < 30 years and weighing < 70 kg were significantly associated with VVR, hyperventilation, and nausea (p < 0.005). Undergraduates and Urdu speaking donors also had a significant association with fainting and nausea, respectively (p < 0.05).  . The prevalence of adverse events was low at our tertiary center. A VVR was the predominant adverse reaction and was associated with age and weight. Our study highlights the importance of these parameters in the donation process. A well-trained and experienced phlebotomist and pre-evaluation counseling of blood donors could further minimize the adverse reactions.

Magnesium, stress and neuropsychiatric disorders.

PubMed

Galland, L

Magnesium has a profound effect on neural excitability; the most characteristic signs and symptoms of Mg deficiency are produced by neural and neuromuscular hyperexcitability. These create a constellation of clinical findings termed tetany syndrome (TS). TS symptoms include muscle spasms, cramps and hyperarousal, hyperventilation and asthenia. Physical signs (Chvostek's, Trousseau's or von Bonsdorff's) and abnormalities of the electromyogram or electroencephalogram can usually be elicited. Signs and symptoms of TS are frequently encountered in clinical practice, especially among patients with functional or stress-related disorders. The role of Mg deficit in TS is suggested by relatively low levels of serum or erythrocyte Mg and by the clinical response to oral Mg salts, which has been demonstrated in controlled studies. Among the more serious neurologic sequelae of TS are migraine attacks, transient ischemic attacks, sensorineural hearing loss and convulsions. Mg deficiency may predispose to hyperventilation and may sensitize the cerebral vasculature to the effects of hypocarbia. Mg deficiency increases susceptibility to the physiologic damage produced by stress, and Mg administration has a protective effect; studies on noise stress and noise-induced hearing loss are taken as an example. In addition, the adrenergic effects of psychological stress induce a shift of Mg from the intracellular to the extracellular space, increasing urinary excretion and eventually depleting body stores. Drugs used in neurology and psychiatry may affect Mg levels in blood and may diminish signs of tetany, making assessment of Mg status more difficult. Pharmacologic use of Mg can decrease neurologic deficit in experimental head trauma, possibly by blockade of N-methyl-D-aspartate receptors. In conjunction with high doses of pyridoxine, Mg salts benefit 40% of patients with autism, possibly by an effect on dopamine metabolism.

The ventilatory responsiveness to CO2 below eupnoea as a determinant of ventilatory stability in sleep

PubMed Central

Dempsey, Jerome A; Smith, Curtis A; Przybylowski, Tadeuez; Chenuel, Bruno; Xie, Ailiang; Nakayama, Hideaki; Skatrud, James B

2004-01-01

Sleep unmasks a highly sensitive hypocapnia-induced apnoeic threshold, whereby apnoea is initiated by small transient reductions in arterial CO2 pressure (PaCO2) below eupnoea and respiratory rhythm is not restored until PaCO2 has risen significantly above eupnoeic levels. We propose that the ‘CO2 reserve’ (i.e. the difference in PaCO2 between eupnoea and the apnoeic threshold (AT)), when combined with ‘plant gain’ (or the ventilatory increase required for a given reduction in PaCO2) and ‘controller gain’ (ventilatory responsiveness to CO2 above eupnoea) are the key determinants of breathing instability in sleep. The CO2 reserve varies inversely with both plant gain and the slope of the ventilatory response to reduced CO2 below eupnoea; it is highly labile in non-random eye movement (NREM) sleep. With many types of increases or decreases in background ventilatory drive and PaCO2, the slope of the ventilatory response to reduced PaCO2 below eupnoea remains unchanged from control. Thus, the CO2 reserve varies inversely with plant gain, i.e. it is widened with hyperventilation and narrowed with hypoventilation, regardless of the stimulus and whether it acts primarily at the peripheral or central chemoreceptors. However, there are notable exceptions, such as hypoxia, heart failure, or increased pulmonary vascular pressures, which all increase the slope of the CO2 response below eupnoea and narrow the CO2 reserve despite an accompanying hyperventilation and reduced plant gain. Finally, we review growing evidence that chemoreceptor-induced instability in respiratory motor output during sleep contributes significantly to the major clinical problem of cyclical obstructive sleep apnoea. PMID:15284345

Delivery of helium–oxygen mixture during spontaneous breathing: evaluation of three high-concentration face masks.

PubMed

Roche-Campo, Ferran; Vignaux, Laurence; Galia, Fabrice; Lyazidi, Aissam; Vargas, Frédéric; Texereau, Joëlle; Apiou-Sbirlea, Gabriela; Jolliet, Philippe; Brochard, Laurent

2011-11-01

To evaluate the efficacy of delivering a mixture of helium and oxygen gas (He–O2) in spontaneous ventilation. Three high oxygen flow reservoir masks were tested: the Heliox21, specifically designed for helium; the Hi-Ox80 mask, with an inspiratory and an expiratory valve; and a standard high-concentration face mask. This prospective randomized crossover study was performed in six healthy volunteers in a laboratory setting. Volunteers breathed a mixture of 78% He/22% O2 through each of the masks under two different breathing conditions (rest and hyperventilation: minute ventilation of 14.9 ± 6.1 and 26.7 ± 8.7 L min(−1), respectively) and four different He–O2 flow rates (7, 10, 12, and 15 L min(−1)). A nasopharyngeal catheter was used to estimate He pharyngeal concentration (Fp [He]) in the airways in order to determine the percentage of contamination with room air (% air cont) at end-expiration. Under all testing conditions, the Hi-Ox80 mask presented a significantly lower % air cont. During resting breathing pattern, a Fp [He] higher than 50% was achieved in 54% of the tests performed with the Hi-Ox80 mask compared to 29% for the Heliox21 mask and only 17% for the standard mask. At hyperventilation, a Fp [He] higher than 50% was achieved in 17% of the tests performed with the Hi-Ox mask compared to 4% for the other two masks. He–O2 administration via the usual high-concentration reservoir masks results in significant dilution by room air. The Hi-Ox80 mask minimized room air contamination and much more frequently achieved a pharyngeal He concentration higher than 50%.

[Gas embolism in the rat].

PubMed

Lagneaux, D; Bodson, L; Remacle, R

1982-11-01

Gaseous carbon dioxide was used to produce experimental pulmonary embolism in anaesthetized rats, the vagal nerves of which were either intact or severed. 1. Within seconds following intravenous CO2 injection, pulmonary hypertension, moderate systemic hypotension and bradycardia occurred. After a short hyperventilation period, intact rats showed a brief and transient apnea. Vagotomy suppresses (1) apnea presumably by interruption of reflexes from J pulmonary receptors (Paintal, 1967) and (2) bradycardia by the same token or by suppression of a reflex from auricular origin (Thorén, 1976). 2. Following that initial phase, the events were totally dependent on the right ventricular ability to overcome the pulmonary vascular resistance. If it failed, left and right pressures fell and a secondary apnea followed systemic hypotension. Vagotomy had no effect at this stage. Only half of all animals showed these features. 3. Pulmonary hypertension and hyperventilation lasted twenty minutes at least in intact rats, while vagotomized ones showed an evolution toward acute pulmonary oedema and death. 4. With the same amount of CO2/kg, the dogs of Verstappen et al. (1977) showed only minimal cardio-vascular alterations. The mode of effective embolization in the two species was probably different, as a function of the respective circulation times. But this geometrical point of view is not the only one to be considered: in rats, the rise of pulmonary arterial blood pressure remains even when mechanical obstruction by bubbles has dissipated and a local prolonged vasospasm could be advocated. 5. Acute pulmonary oedema rapidly occurring in vagotomized rats seems to be related to the hyperinflation (very large tidal volume) as also seen in this species with other intensive respiratory drives.

Centrally administered verapamil prevents the autonomic reaction to visceral pain in sheep.

PubMed

Kania, B F; Brytan, M; Tomaszewska, D

2009-02-01

The significant role of voltage gated calcium channels (VGCC) L-type antagonists used concomitantly with opioids in attenuation of clinical pain has been confirmed. The aim of this study was to evaluate the effect of centrally administered verapamil on behavior and biochemical parameters in sheep that have undergone experimental duodenal distension (DD) and to determine whether verapamil exerts any anti-nociceptive effects under these conditions. The study was carried out using 24 mature crossbred ewes, each weighing 38-43 kg. Verapamil, a VGCC blocker, was administered through an intracerebroventricular cannula at the following doses: 0.25, 0.5, 1.0 and 2.0mg in toto. Ten minutes later experimental DD was conducted by insertion and the distension of rubber balloon (containing 40 ml of warm water) inserted into sheep duodenum. After 5 min of mechanical DD the following reactions were then observed: the significant increase in behavioral pain responses, i.e. tachycardia, hyperventilation, inhibition of reticulo-ruminal contractions (70% approximately, during 15 min), an increase of plasma catecholamine concentration (over 7-fold increase of epinephrine during 2h following DD, 2-times norepinephrine and +/-80% increase of dopamine). Verapamil infusion administered 10 min prior to DD decreased intensity of visceral pain responses, such as: behavioral changes, tachycardia, hyperventilation, inhibition of the reticulo-rumen motility and efficiently prevented the appearance of catecholamine release. These data demonstrated that the development and persistence of duodenal hyperalgesia depends on the activation of Ca(2+) ion flux leading to neurotransmitters release and modulation of membrane excitability. The observed antinociceptive action of VGCCs type-L blockers suggests that these channels play a crucial role in the modulation of acute visceral hyperalgesia in sheep.

Preoperative gender differences in pulmonary gas exchange in morbidly obese subjects.

PubMed

Zavorsky, Gerald S; Christou, Nicolas V; Kim, Do Jun; Carli, Franco; Mayo, Nancy E

2008-12-01

Morbidly obese men may have poorer pulmonary gas exchange compared to morbidly obese women (see Zavorsky et al., Chest 131:362-367, 2007). The purpose was to compare pulmonary gas exchange in morbidly obese men and women at rest and throughout exercise. Twenty-five women (age=38+/-10 years, 164+/-7 cm, body mass index or BMI = 51+/-7 kg/m(2), peak oxygen consumption or VO(2peak)=2.0+/-0.4 l/min) and 17 men (age=43+/-9 years, 178+/-7 cm, BMI=50+/-10 kg/m(2), VO(2peak)=2.6+/-0.8 l/min) were recruited to perform a graded exercise test on a cycle ergometer with temperature-corrected arterial blood-gas samples taken at rest and every minute of exercise, including peak exercise. At rest, women were 98% predicted for pulmonary diffusion compared to 88% predicted in men. At rest, women had better pulmonary gas exchange compared to the men which was related to women having a lower waist-to-hip ratio (WHR; p<0.01). Only 20% of the subjects had an excessive alveolar-to-arterial oxygen partial pressure difference (>or=25 mmHg) at peak exercise, but 75% of the subjects showed inadequate compensatory hyperventilation at peak exercise (arterial carbon dioxide pressure >35 mmHg), and both were not different between genders. At rest, morbidly obese men have poorer pulmonary gas exchange and pulmonary diffusion compared to morbidly obese women. The better gas exchange in women is related to the lower WHR in the women. During exercise, few subjects showed disturbances in pulmonary gas exchange despite demonstrating poor compensatory hyperventilation at peak exercise.

Changes in arterial blood pressure elicited by severe passive heating at rest is associated with hyperthermia-induced hyperventilation in humans.

PubMed

Fujii, Naoto; Ichinose, Masashi; Honda, Yasushi; Tsuji, Bun; Watanabe, Kazuhito; Kondo, Narihiko; Nishiyasu, Takeshi

2013-01-01

The arterial blood pressure and ventilatory responses to severe passive heating at rest varies greatly among individuals. We tested the hypothesis that the increase in ventilation seen during severe passive heating of resting humans is associated with a decrease in arterial blood pressure. Passive heating was performed on 18 healthy males using hot water immersion to the level of the iliac crest and a water-perfused suit. We then divided the subjects into two groups: MAP(NOTINC) (n = 8), whose mean arterial blood pressure (MAP) at the end of heating had increased by ≤3 mmHg, and MAP(INC) (n = 10), whose MAP increased by >3 mmHg. Increases in esophageal temperature (T (es)) elicited by the heating were similar in the two groups (+2.3 ± 0.3 vs. +2.4 ± 0.4 °C). Early during heating (increase in T (es) was <1.5 °C), MAP, minute ventilation ([Formula: see text]), and end-tidal CO(2) pressure ([Formula: see text]) were similar between the groups. However, during the latter part of heating (increase in T (es) was ≥1.5 °C), the increase in [Formula: see text] and decrease in [Formula: see text] were significantly greater or tended to be greater, while the increase in MAP was significantly smaller in MAP(NOTINC) than MAP(INC). Among all subjects, heating-induced changes in [Formula: see text] significantly and negatively correlated with heating-induced changes in MAP during the latter part of heating (r = -0.52 to -0.74, P < 0.05). These results suggest that, in resting humans, 25-50 % of the variation in the magnitude of the arterial blood pressure response to severe passive heating can be explained by the magnitude of hyperthermia-induced hyperventilation.

The relationship between adverse events during selective serotonin reuptake inhibitor treatment for major depressive disorder and nonremission in the suicide assessment methodology study.

PubMed

Daly, Ella J; Trivedi, Madhukar H; Fava, Maurizio; Shelton, Richard; Wisniewski, Stephen R; Morris, David W; Stegman, Diane; Preskorn, Sheldon H; Rush, A John

2011-02-01

Little is known about the association between antidepressant treatment-emergent adverse events and symptom nonremission in major depressive disorder. The objective of the current analysis was to determine whether particular baseline symptoms or treatment-emergent symptoms (adverse events) during the first 2 weeks are associated with nonremission after 8 weeks of treatment with a selective serotonin reuptake inhibitor (SSRI).Outpatients clinically diagnosed with nonpsychotic major depressive disorder were recruited from 6 primary and 9 psychiatric care sites. Participants (n = 206) were treated with an SSRI antidepressant (citalopram [20-40 mg/d], escitalopram [10-20 mg/d], fluoxetine [20-40 mg/d], paroxetine [20-40 mg/d], paroxetine CR [25-37.5 mg/d], or sertraline [50-150 mg/d]) for 8 weeks. Remission was defined as having a score of 5 or less on the 16-item Quick Inventory of Depressive Symptomatology-Clinician-Rated at week 8, or using last observation carried forward. Adverse events were identified using the 55-item Systematic Assessment for Treatment Emergent Events-Systematic Inquiry completed by participants at baseline and week 2.Findings indicated that the emergence of adverse events of weakness/fatigue, strange feeling, and trouble catching breath/hyperventilation at week 2 were independently associated with lack of remission even after controlling for the potential confounders of baseline depressive severity, anxious symptoms, antidepressant medication, chronic depression, race, burden of general medical comorbidity, and time in study. Hearing/seeing things appeared to have a protective effect. In conclusion, during SSRI treatment, the adverse events of weakness/fatigue, feeling strange, and trouble catching breath/hyperventilation are associated with nonremission, possibly due to lower adherence, early attrition, difficulty increasing the dose, and reduced efficacy.

Efficacy and safety of a video-EEG protocol for genetic generalized epilepsies.

PubMed

De Marchi, Luciana Rodrigues; Corso, Jeana Torres; Zetehaku, Ana Carolina; Uchida, Carina Gonçalves Pedroso; Guaranha, Mirian Salvadori Bittar; Yacubian, Elza Márcia Targas

2017-05-01

Video-EEG has been used to characterize genetic generalized epilepsies (GGE). For best performance, sleep recording, photic stimulation, hyperventilation, and neuropsychological protocols are added to the monitoring. However, risks and benefits of these video-EEG protocols are not well established. The aim of this study was to analyze the efficacy and safety of a video-EEG neuropsychological protocol (VNPP) tailored for GGE and compare its value with that of routine EEG (R-EEG). We reviewed the VNPP and R-EEG of patients with GGE. We considered confirmation of the clinical suspicion of a GGE syndrome and characterization of reflex traits as benefits; and falls, injuries, psychiatric and behavioral changes, generalized tonic-clonic (GTC) seizures, and status epilepticus (SE) as the main risks of the VNPP. The VNPPs of 113 patients were analyzed. The most common epileptic syndrome was juvenile myoclonic epilepsy (85.8%). The protocol confirmed a GGE syndrome in 97 patients and 62 had seizures. Sleep recording had a provocative effect in 51.2% of patients. The second task that showed highest efficacy was praxis (39.3%) followed by hyperventilation (31.3%). Among the risks, 1.8% had GTC seizures and another 1.8%, SE. Eighteen percent of patients had persistently normal R-EEG, 72.2% of them had discharges during VNPP. Generalized tonic-clonic seizures, myoclonic status epilepticus, and repeated seizures were the main risks of VNPP present in 6 (5.31%) patients while there were no complications during R-EEG. The VNPP in GGE is a useful tool in diagnosis and characterization of reflex traits, and is a safe procedure. Its use might preclude multiple R-EEG exams. Copyright © 2017 Elsevier Inc. All rights reserved.

A Novel Physiological Investigation of the Functional Residual Capacity by the Bias Flow Nitrogen Washout Technique in Infants

PubMed Central

Morris, Mohy G.

2011-01-01

Summary The dynamic functional residual capacity (FRCdyn), the lung volume most routinely measured in infants, is an unreliable volume landmark. In addition to the FRCdyn, we measured the (passive) static FRC (FRCst) by inducing a brief post-hyperventilation apnea (PHA) in 33 healthy infants aged 7.4–127.2 weeks. A commercial system for nitrogen (N2) washout to measure FRC, and a custom made system to monitor and record flow and airwayopening pressure signals in real-time were used in unison. Infants were manually hyperventilated to induce a PHA. After the last passive expiration, FRCst was estimated by measuring the volume of N2 expired after end-passive expiratory switching of the inspired gas from room air to 100% oxygen during the post-expiratory apneic pause. Repeatable intrasubject FRCst and FRCdyn measurements overlapped in most infants including the younger ones (P = 0.2839). Mean (95% confidence interval [CI]) FRCst was 21.1 (20.0–22.3), and error-corrected FRCdyn was 21.4 (20.4–22.4) ml/kg. Mean (washout time [t]) tFRCst was longer than tFRCdyn 60 sec (95% CI 55–65) versus 47 sec (95% CI 43–51) (P<0.0001). The FRC and washout time were dependent on body length, weight and age. We conclude that the FRCst is not different from the FRCdyn in infants. The FRCst is a reliable volume landmark because the PHA stabilizes the end-expiratory level by potentially abolishing the sedated infant’s breathing strategies. The FRCst lacks potential sources of errors and disadvantages associated with measuring the FRCdyn. The findings cast significant doubt on the traditional physiology of air trapping in healthy infants’ lungs. PMID:19499588

Restoring heat stress-associated reduction in middle cerebral artery velocity does not reduce fatigue in the heat.

PubMed

Keiser, S; Flück, D; Stravs, A; Hüppin, F; Lundby, C

2015-06-01

Heat-induced hyperventilation may reduce PaCO2 and thereby cerebral perfusion and oxygenation and in turn exercise performance. To test this hypothesis, eight volunteers completed three incremental exercise tests to exhaustion: (a) 18 °C ambient temperature (CON); (b) 38 °C (HEAT); and (c) 38 °C with addition of CO2 to inspiration to prevent the hyperventilation-induced reduction in PaCO2 (HEAT + CO2 ). In HEAT and HEAT + CO2 , rectal temperature was elevated prior to the exercise tests by means of hot water submersion and was higher (P < 0.05) than in CON. Compared with CON, ventilation was elevated (P < 0.01), and hence, PaCO2 reduced in HEAT. This caused a reduction (P < 0.05) in mean cerebral artery velocity (MCAvmean ) from 68.6 ± 15.5 to 53.9 ± 10.0 cm/s, which was completely restored in HEAT + CO2 (68.8 ± 5.8 cm/s). Cerebral oxygenation followed a similar pattern. V ˙ O 2   m a x was 4.6 ± 0.1 L/min in CON and decreased (P < 0.05) to 4.1 ± 0.2 L/min in HEAT and remained reduced in HEAT + CO2 (4.1 ± 0.2 L/min). Despite normalization of MCAvmean and cerebral oxygenation in HEAT + CO2 , this did not improve exercise performance, and thus, the reduced MCAvmean in HEAT does not seem to limit exercise performance. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Downregulation of cough by exercise and voluntary hyperpnea.

PubMed

Fontana, Giovanni A

2010-01-01

No information exists on the effects of hyperpnea on the sensory and cognitive aspects of coughing evoked by inhalation of tussigenic agents. The threshold for the cough reflex induced by inhalation of increasing concentrations of ultrasonically nebulized distilled water (fog), and the index of cough reflex sensitivity, was assessed in 12 healthy humans in control conditions, during exercise, and during voluntary isocapnic hyperventilation (VIH) to the same level as the exercise. The intensity of the urge-to-cough (UTC), a cognitive component of coughing, was also recorded throughout the trials. The log-log relationship between inhaled fog concentrations and the correspondingly evoked UTC values, an index of the perceptual magnitude of the UTC sensitivity, was also calculated. Cough appearance was always assessed audiovisually. At an exercise level of 80% of anaerobic threshold, the mean cough threshold was increased from a control value of 1.03 +/- 0.65 to 2.25 +/- 1.14 ml/min (p < 0.01), i.e., cough sensitivity was downregulated. With VIH, the mean (+/-SD) threshold increased from 1.03 +/- 0.65 to 2.42 +/- 1.16 ml/min (p < 0.01), a similar downregulation. With exercise and VIH compared with control, mean UTC values at cough threshold were not significantly changed: control, 3.83 +/- 1.11 cm; exercise, 3.12 +/- 0.82 cm; VIH, 4.08 +/- 1.67 cm. Since the slopes of the log fog concentration/log UTC value were approximately halved during exercise and VIH compared with control, the UTC sensitivity to fog was depressed (p < 0.01). The results indicate that the adjustments brought into action by exercise-induced or voluntary hyperventilation exert inhibitory influences on the sensory and cognitive components of fog-induced cough.

[P300 potential in chldren with psychogenic nonepileptic events and tension headache].

PubMed

Steczkowska, Małgorzata; Stolarska-Weryńska, Urszula; Fiederer, Krystyna; Kaciński, Marek

2016-01-01

Psychotherapy is being used as the primary treatment in nonepileptic psychogenic seizures and tension headaches in children. Children's intelectual functioning is related to certain endogenous neurophysiological parameters. The goal of this study was to establish whether the endogenous potential P300 is different in children with nonepileptic psychogenic events and with tension headaches, and whether it changes under the influence of the cognitive-behavioral psychotherapy. The study included a group of 47 children: 20 with nonepileptic psychogenic seizures (18 girls and 2 boys), aged 11.09-17.11 years, and 27 children with tension headache (25 girls and 2 boys), aged 10.11-17.11 years. The P300 potential was induced using an auditory stimulus. The reaction time, the amount of mistakes and the percentage of attention focus was measured in all children. All children attended 8-10 psychotherapy sessions. The P300 potential was registered before and after the course of therapy, and additionally in both cycles also after a 3 minutes hyperventilation. Medium P300 parameters were closer to normal in the group of children with tension headaches rather than in the group with nonepileptic seizures. The shorter was the reaction time in the first measurement, the higher the attention score and the shorter the reaction time in the second measurement - this was visible in the results of children with nonepileptic seizures, in contrast to children with tension headaches. The use of hyperventilation caused a noticeable extension of the reaction time in the P300 measurement, with other components unchanged (mistake count and percentage of attention focus). The endogenous potential P300 does vary, although on a statistically insignificant level, in groups of children with tension headaches and nonepileptic seizures.

The hemodynamic effects of prolonged respiratory alkalosis in anesthetized newborn piglets.

PubMed

Jundi, K; Barrington, K J; Henderson, C; Allen, R G; Finer, N N

2000-04-01

To test the hypothesis that prolonged alkalosis decreases cardiac output and, furthermore, exacerbates hypoxic pulmonary vasoconstriction, as respiratory alkalosis is frequently induced as a therapy for persistent pulmonary hypertension of the newborn despite a lack of controlled evidence of improved outcomes. Potential adverse effects of prolonged alkalosis have been demonstrated. Two groups (control, n = 6, and hypocapnic alkalosis, n = 6) of 1-3 day old fentanyl-anesthetized, vecuronium-paralyzed piglets were instrumented to measure cardiac index (CI) and mean systemic (MAP) and pulmonary (PAP) arterial pressures. Baseline values were recorded. Alveolar hypoxia was then induced to achieve an arterial oxygen saturation of between 50 and 60% for 15 min. Respiratory alkalosis was then induced, by increasing ventilation to achieve a pH between 7.55-7.60, and was continued for 240 min. Inspired carbon dioxide was used with hyperventilation in the control group to maintain pressure of arterial carbon dioxide (PaCO2) at 35-45 mmHg and pH of 7.35-7.45. Hypoxia was induced again at 15 and 240 min. Pulmonary and systemic vascular resistances (PVR and SVR) were calculated. Prolonged alkalosis led to a significant and progressive fall in mean MAP from 61 (SD 7) mmHg at the start of the study falling to 50 (SD 6.9, p = 0.043), with no effect on CI. Calculated SVR decreased (0.45 SD 0.03 vs 0.36 SD 0.05). There were no statistically significant changes in any of the variables in the control group. Neither acute nor prolonged respiratory alkalosis had a significant effect on hypoxic pulmonary vasoconstriction. Prolonged hyperventilation leads to systemic hypotension, however it does not exacerbate hypoxic pulmonary vasoconstriction.

Low sodium intake does not impair renal compensation of hypoxia-induced respiratory alkalosis.

PubMed

Höhne, Claudia; Boemke, Willehad; Schleyer, Nora; Francis, Roland C; Krebs, Martin O; Kaczmarczyk, Gabriele

2002-05-01

Acute hypoxia causes hyperventilation and respiratory alkalosis, often combined with increased diuresis and sodium, potassium, and bicarbonate excretion. With a low sodium intake, the excretion of the anion bicarbonate may be limited by the lower excretion rate of the cation sodium through activated sodium-retaining mechanisms. This study investigates whether the short-term renal compensation of hypoxia-induced respiratory alkalosis is impaired by a low sodium intake. Nine conscious, tracheotomized dogs were studied twice either on a low-sodium (LS = 0.5 mmol sodium x kg body wt-1 x day-1) or high-sodium (HS = 7.5 mmol sodium x kg body wt-1 x day-1) diet. The dogs breathed spontaneously via a ventilator circuit during the experiments: first hour, normoxia (inspiratory oxygen fraction = 0.21); second to fourth hour, hypoxia (inspiratory oxygen fraction = 0.1). During hypoxia (arterial PO2 34.4 +/- 2.1 Torr), plasma pH increased from 7.37 +/- 0.01 to 7.48 +/- 0.01 (P < 0.05) because of hyperventilation (arterial PCO2 25.6 +/- 2.4 Torr). Urinary pH and urinary bicarbonate excretion increased irrespective of the sodium intake. Sodium excretion increased more during HS than during LS, whereas the increase in potassium excretion was comparable in both groups. Thus the quick onset of bicarbonate excretion within the first hour of hypoxia-induced respiratory alkalosis was not impaired by a low sodium intake. The increased sodium excretion during hypoxia seems to be combined with a decrease in plasma aldosterone and angiotensin II in LS as well as in HS dogs. Other factors, e.g., increased mean arterial blood pressure, minute ventilation, and renal blood flow, may have contributed.

Cerebral blood volume in humans by NIRS and PET

NASA Astrophysics Data System (ADS)

Pott, Frank; Knudsen, Gitte M.; Rostrup, Egill; Ide, Kojiro; Secher, Niels H.; Paulson, Olaf B.

1997-12-01

Near infrared spectroscopy (NIRS) determined changes in the cerebral blood volume (CBV) were compared to those obtained by positron emission tomography (PET) in five healthy volunteers (2 females). Two NIRS optodes were placed on the left forehead and NIRS-CBV was derived from the sum of oxyhemoglobin and deoxyhemoglobin. CBV changes were induced by hyperventilation and inhalation of 6% CO2. After 2 min inhalation of labeled carbon monoxide, data were sampled during 8 min for both PET- and NIRS-CBV as well as for the arterial carbon dioxide tension (PaCO2). The region of interest for PET-CBV was `banana-shaped' with boundaries corresponding to the position of the NIRS optodes on the transmission scan and to a depth of approximately 2 cm. During hyperventilation, PaCO2 decreased from 5.2 (4.6 - 5.8) to 4.6 (4.2 - 4.9) kPa and equally PET-CBV (from 3.9 (2.5 - 5.2) to 3.6 (3.0 - 4.8) ml (DOT) 100 g-1) and NIRS-CBV were reduced (by -0.14 [-0.38 - 0.50] ml (DOT) 100 g-1). During hypercapnia PaCO2 increased to 6.0 (5.9 - 7.0) kPa accompanied by parallel changes in PET- (to 4.5 (3.9 - 4.9) ml (DOT) 100 g-1) and NIRS-CBV (by 0.04 [-0.02 - 0.30] ml (DOT) 100 g-1) and the two variables were correlated (r equals 0.78, p < 0.05). In conclusion, with a moderate change in the arterial carbon dioxide tension, the cerebral blood volumes determined by near infrared spectroscopy and by positron emission tomography change in parallel but the change in NIRS-CBV is small compared to that obtained by PET.

Studying cerebral hemodynamics and metabolism using simultaneous near-infrared spectroscopy and transcranial Doppler ultrasound: a hyperventilation and caffeine study

PubMed Central

Yang, Runze; Brugniaux, Julien; Dhaliwal, Harinder; Beaudin, Andrew E; Eliasziw, Misha; Poulin, Marc J; Dunn, Jeff F

2015-01-01

Caffeine is one of the most widely consumed psycho-stimulants in the world, yet little is known about its effects on brain oxygenation and metabolism. Using a double-blind, placebo-controlled, randomized cross-over study design, we combined transcranial Doppler ultrasound (TCD) and near-infrared spectroscopy (NIRS) to study caffeine's effect on middle cerebral artery peak blood flow velocity (Vp), brain tissue oxygenation (StO2), total hemoglobin (tHb), and cerebral oxygen metabolism (CMRO2) in five subjects. Hyperventilation-induced hypocapnia served as a control to verify the sensitivity of our measurements. During hypocapnia (∼16 mmHg below resting values), Vp decreased by 40.0 ± 2.4% (95% CI, P < 0.001), while StO2 and tHb decreased by 2.9 ± 0.3% and 2.6 ± 0.4%, respectively (P = 0.003 and P = 0.002, respectively). CMRO2, calculated using the Fick equation, was reduced by 29.3 ± 9% compared to the isocapnic-euoxia baseline (P < 0.001). In the pharmacological experiments, there was a significant decrease in Vp, StO2, and tHb after ingestion of 200 mg of caffeine compared with placebo. There was no significant difference in CMRO2 between caffeine and placebo. Both showed a CMRO2 decline compared to baseline showing the importance of a placebo control. In conclusion, this study showed that profound hypocapnia impairs cerebral oxidative metabolism. We provide new insight into the effects of caffeine on cerebral hemodynamics. Moreover, this study showed that multimodal NIRS/TCD is an excellent tool for studying brain hemodynamic responses to pharmacological interventions and physiological challenges. PMID:25907789

Cerebral blood volume in humans by NIRS and PET

NASA Astrophysics Data System (ADS)

Pott, Frank; Knudsen, Gitte M.; Rostrup, Egill; Ide, Kojiro; Secher, Niels H.; Paulson, Olaf B.

1998-01-01

Near infrared spectroscopy (NIRS) determined changes in the cerebral blood volume (CBV) were compared to those obtained by positron emission tomography (PET) in five healthy volunteers (2 females). Two NIRS optodes were placed on the left forehead and NIRS-CBV was derived from the sum of oxyhemoglobin and deoxyhemoglobin. CBV changes were induced by hyperventilation and inhalation of 6% CO2. After 2 min inhalation of labeled carbon monoxide, data were sampled during 8 min for both PET- and NIRS-CBV as well as for the arterial carbon dioxide tension (PaCO2). The region of interest for PET-CBV was `banana-shaped' with boundaries corresponding to the position of the NIRS optodes on the transmission scan and to a depth of approximately 2 cm. During hyperventilation, PaCO2 decreased from 5.2 (4.6 - 5.8) to 4.6 (4.2 - 4.9) kPa and equally PET-CBV (from 3.9 (2.5 - 5.2) to 3.6 (3.0 - 4.8) ml (DOT) 100 g-1) and NIRS-CBV were reduced (by -0.14 [-0.38 - 0.50] ml (DOT) 100 g-1). During hypercapnia PaCO2 increased to 6.0 (5.9 - 7.0) kPa accompanied by parallel changes in PET- (to 4.5 (3.9 - 4.9) ml (DOT) 100 g-1) and NIRS-CBV (by 0.04 [-0.02 - 0.30] ml (DOT) 100 g-1) and the two variables were correlated (r equals 0.78, p < 0.05). In conclusion, with a moderate change in the arterial carbon dioxide tension, the cerebral blood volumes determined by near infrared spectroscopy and by positron emission tomography change in parallel but the change in NIRS-CBV is small compared to that obtained by PET.

Severely impaired health-related quality of life in chronic hyperventilation patients: exploratory data.

PubMed

Chenivesse, Cécile; Similowski, Thomas; Bautin, Nathalie; Fournier, Clément; Robin, Sophie; Wallaert, Benoît; Perez, Thierry

2014-03-01

Patients with hyperventilation syndrome (HVS) report severe symptom-related suffering and often complain from insufficient medical attention. However, quality of life data in this context are scarce. We aimed at assessing the health-related quality of life (HRQoL) of HVS patients. Twenty-one HVS patients with extensive cardiorespiratory workup including cardiopulmonary exercise testing (CPET) filled in the generic SF-36 questionnaire and the results were compared to French normal values. Correlations between SF36 dimensions and clinical and functional data were established. All SF-36 scores were markedly decreased in HVS patients compared to healthy subjects: Physical Functioning: 44 ± 24, Social Functioning: 57 ± 27, Role Physical: 21 ± 32, Role Emotional: 48 ± 42, Mental Health: 51 ± 27, Vitality: 34 ± 20, Body Pain: 41 ± 21, General Health: 42 ± 21. These figures were all significantly lower in the HVS patients respective to the normal reference population. They were also lower than corresponding values published in patients with asthma or chronic obstructive pulmonary disease (COPD). "Vitality" and "Physical Functioning" scores were correlated with Nijmegen score (r = -0.594, p = 0.047) and peak respiratory frequency during CPET (r = -0.644, p = 0.019). The SF-36 Social Functioning score was correlated with the ventilatory threshold (r = 0.629, p = 0.034), peak V'E/V'CO2 (ventilation/CO2 production) (r = 0.650, p = 0.016) and peak PaCO2 (r = -0.664, p = 0.027). In conclusion, this study shows that HRQoL can be severely impaired in patients with HVS, which is one more reason to take this condition seriously. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of changes in PCO2 and body positions on intraocular pressure during general anaesthesia.

PubMed

Hvidberg, A; Kessing, S V; Fernandes, A

1981-08-01

Elevated arterial carbon dioxide tension, induced by the administration of CO2 via the respiratory air or by hypoventilation, entailed a gradual increase in the IOP in patients without eye diseases under general anaesthesia. A sudden cessation of CO2 administration or hyperventilation caused such a rapid, simultaneous fall in IOP to values below the initial level that the pressure variations must be of vascular nature, presumably related to changes in choroidal blood volume. The above-mentioned procedures always cause a change in the central venous pressure (CVP) simultaneously with the IOP changes. Alterations of the CVP induced by hydrostatic factors in postural changes, placing the head 15 degrees above or below the horizontal level while keeping the PaCO2 constant, caused IOP changes of the same configuration and magnitude as described above. It is concluded, therefore, that presumably the CO2-conditioned IOP changes are due predominantly to changes in central venous pressure, being one link in a CO2-conditioned action upon the general circulation, entailing passive secondary changes in the choroidal venous blood volume and thereby an influence upon the IOP. On the basis of the present results it appears rational to recommend hyperventilation to keep the PaCO2 between 25 and 30 mm and a 15 degree anti-Trendelenburg position in operations on the eye under general anaesthesia, since both procedures afford a low central venous pressure and consequently a low pressure in the posterior segment of the eye, with its attendant advantages as regards vitreous complications and the insertion of intraocular lenses. Owing to the risk of an unacceptable fall in BP in the combined procedure, a frequent checking of the BP is needed.

Pediatric Major Head Injury: Not a Minor Problem.

PubMed

Leetch, Aaron N; Wilson, Bryan

2018-05-01

Traumatic brain injury is a highly prevalent and devastating cause of morbidity and mortality in children. A rapid, stepwise approach to the traumatized child should proceed, addressing life-threatening problems first. Management focuses on preventing secondary injury from physiologic extremes such as hypoxemia, hypotension, prolonged hyperventilation, temperature extremes, and rapid changes in cerebral blood flow. Initial Glasgow Coma Score, hyperglycemia, and imaging are often prognostic of outcome. Surgically amenable lesions should be evacuated promptly. Reduction of intracranial pressure through hyperosmolar therapy, decompressive craniotomy, and seizure prophylaxis may be considered after stabilization. Nonaccidental trauma should be considered when evaluating pediatric trauma patients. Copyright © 2017 Elsevier Inc. All rights reserved.

Cardiorespiratory interactions in neural circulatory control in humans.

PubMed

Shamsuzzaman, A S; Somers, V K

2001-06-01

The reflex mechanisms and interactions described in this overview provide some explanation for the range of neural circulatory responses evident during changes in breathing. The effects described represent the integrated responses to activation of several reflex mechanisms, including peripheral and central chemoreflexes, arterial baroreflexes, pulmonary stretch receptors, and ventricular mechanoreceptors. These interactions occur on a dynamic basis and the transfer characteristics of any single interaction are, in all likelihood, also highly dynamic. Nevertheless, it is only by attempting to understand individual reflexes and their modulating influences that a more thorough understanding of the responses to complex phenomena such as hyperventilation, apnea, and obstructive sleep apnea can be better understood.

Controlling public speaking jitters: making the butterflies fly in formation.

PubMed

Harvey, Hannah; Baum, Neil

2014-01-01

Nearly every person who has been asked to give a speech or who has volunteered to make a presentation to a group of strangers develops fear and anxiety prior to the presentation. Most of us, the authors included, start hyperventilating, our pulse quickens, and we feel a little weak in the knees. We grab the lectern and our knuckles turn white as we hold on for dear life. This is a normal response that everyone experiences. However, this stress can be controlled and made manageable by understanding the stress response cycle and practicing a few techniques that calm those butterflies flying around in the pit of your stomach.

Monitoring of endogenous carbon monoxide dynamics in human breath by tunable diode laser

NASA Astrophysics Data System (ADS)

Stepanov, Eugene V.; Daraselia, Mikhail V.; Zyrianov, Pavel V.; Shulagin, Yurii A.; Skrupskii, Vladimir A.

1996-01-01

High sensitive CO gas analyzer based on tunable diode laser (TDL) was used as a real time monitor of endogenous carbon monoxide in a set of breath physiology experiments. The measurements of the CO content dynamics in exhaled air with 10 ppb sensitivity were attended with detection of carbon dioxide and O2 in breath, lung ventilation parameters, heart rate and blood analysis using conventional techniques. Temporal variations of endogenous CO in human breath caused by hyperoxia, hypoxia, hyperventilation and sport loading were first studied in real time. Scattering of the CO variation time constants was observed for different tested persons. Possible reasons for this scattering related with the organisms' physiology peculiarities are discussed.

Endogenous CO dynamics monitoring in breath by tunable diode laser

NASA Astrophysics Data System (ADS)

Kouznetsov, Andrian I.; Stepanov, Eugene V.; Shulagin, Yurii A.; Skrupskii, Vladimir A.

1996-04-01

High sensitive CO gas analyzer based on tunable diode laser (TDL) was used as a real time monitor of endogenous carbon monoxide in a set of breath physiology experiments. The measurements of the CO content dynamics in exhaled air with 10 ppb sensitivity were attended with detection of carbon dioxide and O2 in breath, lung ventilation parameters, heart rate and blood analysis using conventional techniques. Variations of endogenous CO in human breath caused by hyperoxia, hypoxia, hyperventilation as well as sport loading were studied in real time. Scattering of the CO variation time constants was observed for different tested persons. Possible reasons for this scattering related with the organisms' physiology peculiarities are discussed.

The effect of varying alveolar carbon dioxide levels on free recall.

PubMed

Marangoni, A H; Hurford, D P

1990-05-01

A recent study suggested that students who have increased minute ventilation receive poorer grades. The present study was interested in determining the role alveolar carbon dioxide (CO2) levels play with cognitive abilities. A free recall task was used to examine list learning under two conditions of alveolar CO2 level: normal and decreased. The results suggested that decreased alveolar CO2 level affect the participant's ability to rehearse and recall information. It was concluded that conditions that reduce alveolar CO2 levels, such as hyperventilation resulting from stress, nervousness, or inappropriate breathing habits, can lead to poorer learning. If these conditions produce a habitual breathing pattern, the academic performance of the individual may suffer.

Effect of short-term exercise-heat acclimation on ventilatory and cerebral blood flow responses to passive heating at rest in humans.

PubMed

Fujii, Naoto; Tsuji, Bun; Honda, Yasushi; Kondo, Narihiko; Nishiyasu, Takeshi

2015-09-01

Hyperthermia induces hyperventilation and cerebral hypoperfusion in resting humans. We tested the hypothesis that short-term exercise-heat acclimation would alleviate those effects. Twenty healthy male subjects were divided into two groups that performed exercise training in the heat (TR-HEAT, n = 10) or cold (TR-COLD, n = 10). Before and after the training, the subjects in both groups participated in passive-heat tests at rest. Training was performed at 37°C (TR-HEAT) or 10°C (TR-COLD) and entailed four 20-min bouts of cycling at 50% peak oxygen uptake separated by 10-min recoveries daily for 6 consecutive days. After TR-HEAT, esophageal temperature was lowered when measured before and during passive heating, as was the esophageal temperature threshold for cutaneous active vasodilation, whereas plasma volume was increased (all P < 0.05). These traditional indices of successful heat acclimation were not all induced by TR-COLD (all P > 0.05). TR-HEAT had no significant effect on passive heating-induced increases in minute ventilation, even when evaluated as the esophageal temperature threshold for increases in minute ventilation and the slope relating minute ventilation to esophageal temperature (all P > 0.05). By contrast, TR-HEAT attenuated the passive heating-induced reduction in the cerebral vascular conductance index (middle cerebral artery mean blood velocity/mean arterial pressure) (all P < 0.05). TR-COLD did not attenuate the increase in minute ventilation or the decrease in the cerebral vascular conductance index observed during passive heating (all P > 0.05). These data suggest that in resting heated humans, short-term heat acclimation achieved through moderate-intensity exercise training (i.e., 50% peak oxygen uptake) in the heat does not influence hyperthermia-induced hyperventilation, but it does potentially attenuate cerebral hypoperfusion. Copyright © 2015 the American Physiological Society.

Adaptation of exercise ventilation during an actively-induced hyperthermia following passive heat acclimation.

PubMed

Beaudin, Andrew E; Clegg, Miriam E; Walsh, Michael L; White, Matthew D

2009-09-01

Hyperthermia-induced hyperventilation has been proposed to be a human thermolytic thermoregulatory response and to contribute to the disproportionate increase in exercise ventilation (VE) relative to metabolic needs during high-intensity exercise. In this study it was hypothesized that VE would adapt similar to human eccrine sweating (E(SW)) following a passive heat acclimation (HA). All participants performed an incremental exercise test on a cycle ergometer from rest to exhaustion before and after a 10-day passive exposure for 2 h/day to either 50 degrees C and 20% relative humidity (RH) (n = 8, Acclimation group) or 24 degrees C and 32% RH (n = 4, Control group). Attainment of HA was confirmed by a significant decrease (P = 0.025) of the esophageal temperature (T(es)) threshold for the onset of E(SW) and a significantly elevated E(SW) (P < or = 0.040) during the post-HA exercise tests. HA also gave a significant decrease in resting T(es) (P = 0.006) and a significant increase in plasma volume (P = 0.005). Ventilatory adaptations during exercise tests following HA included significantly decreased T(es) thresholds (P < or = 0.005) for the onset of increases in the ventilatory equivalents for O(2) (VE/VO(2)) and CO(2) (VE/VCO(2)) and a significantly increased VE (P < or = 0.017) at all levels of T(es). Elevated VE was a function of a significantly greater tidal volume (P = 0.003) at lower T(es) and of breathing frequency (P < or = 0.005) at higher T(es). Following HA, the ventilatory threshold was uninfluenced and the relationships between VO(2) and either VE/VO(2) or VE/VCO(2) did not explain the resulting hyperventilation. In conclusion, the results support that exercise VE following passive HA responds similarly to E(SW), and the mechanism accounting for this adaptation is independent of changes of the ventilatory threshold or relationships between VO(2) with each of VE/VO(2) and VE/VCO(2).

No effect of skin temperature on human ventilation response to hypercapnia during light exercise with a normothermic core temperature.

PubMed

Greiner, Jesse G; Clegg, Miriam E; Walsh, Michael L; White, Matthew D

2010-05-01

Hyperthermia potentiates the influence of CO(2) on pulmonary ventilation (.V(E)). It remains to be resolved how skin and core temperatures contribute to the elevated exercise ventilation response to CO(2). This study was conducted to assess the influences of mean skin temperature (_T(SK)) and end-tidal PCO(2) (P(ET)CO(2)) on .V(E) during submaximal exercise with a normothermic esophageal temperature (T(ES)). Five males and three females who were 1.76 +/- 0.11 m tall (mean +/- SD), 75.8 +/- 15.6 kg in weight and 22.0 +/- 2.2 years of age performed three 1 h exercise trials in a climatic chamber with the relative humidity (RH) held at 31.5 +/- 9.5% and the ambient temperature (T (AMB)) maintained at one of 25, 30, or 35 degrees C. In each trial, the volunteer breathed eucapnic air for 5 min during a rest period and subsequently cycle ergometer exercised at 50 W until T (ES) stabilized at approximately 37.1 +/- 0.4 degrees C. Once T (ES) stabilized in each trial, the volunteer breathed hypercapnic air twice for approximately 5 min with P(ET)CO(2) elevated by approximately +4 or +7.5 mmHg. The significantly (P < 0.05) different increases of P(ET)CO(2) of +4.20 +/- 0.49 and +7.40 +/- 0.51 mmHg gave proportionately larger increases in .V(E) of 10.9 +/- 3.6 and 15.2 +/- 3.6 L min(-1) (P = 0.001). This hypercapnia-induced hyperventilation was uninfluenced by varying the _T(SK) to three significantly different levels (P < 0.001) of 33.2 +/- 1.2 degrees C, to 34.5 +/- 0.8 degrees C to 36.4 +/- 0.5 degrees C. In conclusion, the results support that skin temperature between approximately 33 and approximately 36 degrees C has neither effect on pulmonary ventilation nor on hypercapnia-induced hyperventilation during a light exercise with a normothermic core temperature.

A Comparison of Different Techniques for Interfacing Capnography With Adult and Pediatric Supplemental Oxygen Masks.

PubMed

Phillips, Justin S; Pangilinan, Lance P; Mangalindan, Earl R E; Booze, Joseph L; Kallet, Richard H

2017-01-01

Accurately measuring the partial pressure of end-tidal CO 2 (P ETCO 2 ) in non-intubated patients is problematic due to dilution of expired CO 2 at high O 2 flows and mask designs that may either cause CO 2 rebreathing or inadequately capture expired CO 2 . We evaluated the performance of 2 capnographic O 2 masks (Cap-ONE and OxyMask) against a clinically expedient method using a standard O 2 mask with a flow-directed nasal cannula used for capnography (CapnoLine) in a spontaneous breathing model of an adult and child under conditions of normal ventilation, hypoventilation, and hyperventilation. An ASL-5000 simulator was attached to a manikin face with a catheter port, through which various CO 2 /air mixtures were bled into the ASL-5000 to achieve a P ETCO 2 of 40, 65, and 30 mm Hg. Both P ETCO 2 and inspired P CO 2 were measured at O 2 flows of 5, 10, 15, and 20 L/min (adult model) and 2, 4, 6, 8, and 10 L/min (pediatric model). P ETCO 2 decreased to varying degrees as O 2 flow increased, depending upon the breathing pattern. Although all devices appeared to perform reasonably well under normal and hyperventilation conditions, the clinically expedient method was associated with substantially more CO 2 rebreathing. P ETCO 2 usually deteriorated more under simulated hypoventilation, regardless of the measurement method. Both of the specially designed O 2 capnography masks provided reasonably stable P ETCO 2 without significant CO 2 rebreathing at the commonly used O 2 flows. Because of their open design, P ETCO 2 measured at high O 2 flows may produce artificially lower readings that may not reflect arterial CO 2 levels compared with lower O 2 flows. Copyright © 2017 by Daedalus Enterprises.

Diurnal variation in the control of ventilation in response to rising body temperature during exercise in the heat

PubMed Central

Tsuji, Bun; Honda, Yasushi; Kondo, Narihiko

2016-01-01

We investigated whether heat-induced hyperventilation during exercise is affected by time of day, as diurnal variation leads to higher core temperatures in the evening. Nineteen male subjects were divided into two experiments (protocol 1, n = 10 and protocol 2, n = 9). In protocol 1, subjects performed cycle exercise at 50% peak oxygen uptake in the heat (37°C and 50% RH) in the morning (0600) and evening (1800). Results showed that baseline resting and exercising esophageal temperature (Tes) were significantly (0.5°C) higher in the evening than morning. Minute ventilation (V̇e) increased from 54.3 ± 7.9 and 54.9 ± 6.8 l/min at 10 min to 71.4 ± 8.1 and 76.5 ± 11.8 l/min at 48.5 min in the morning and evening, respectively (both P < 0.01). Time of day had no effect on V̇e (P = 0.44). When V̇e as the output response was plotted against Tes as thermal input, the Tes threshold for increases in V̇e was higher in the evening than morning (37.2 ± 0.7 vs. 36.6 ± 0.6°C, P = 0.009), indicating the ventilatory response to the same core temperature is smaller in the evening. In protocol 2, the circadian rhythm-related higher resting Tes seen in the evening was adjusted down to the same temperature seen in the morning by immersing the subject in cold water. Importantly, the time course of changes in V̇e during exercise were smaller in the evening, but the threshold for V̇e remained higher in the evening than morning (P < 0.001). Collectively, those results suggest that time of day has no effect on time course hyperventilation during exercise in the heat, despite the higher core temperatures in the evening. This is likely due to diurnal variation in the control of ventilation in response to rising core temperature. PMID:27335282

Signal-to-noise ratio of bilateral nonimaging transcranial Doppler recordings of the middle cerebral artery is not affected by age and sex.

PubMed

Katsogridakis, Emmanuel; Dineen, Nicky E; Brodie, Fiona G; Robinson, Thompson G; Panerai, Ronney B

2011-04-01

Differences between transcranial Doppler ultrasonography (TCD) recordings of symmetrical vessels can show true physiologic differences, but can also be caused by measurement error and other sources of noise. The aim of this project was to assess the influence of noise on estimates of dynamic cerebral autoregulation (dCA), and of age, sex and breathing manoeuvres on the signal-to-noise ratio (SNR). Cerebral blood flow (CBF) was monitored in 30 young (<40 years) and 30 older volunteers (age >60 years) during baseline conditions, breath-holding and hyperventilation. Noise was defined as the difference between beat-to-beat values of the two mean CBF velocity (CBFV) signals. Magnitude squared coherence estimates of noise vs. ABP and ABP vs. CBFV were obtained and averaged. A similar approach was adopted for the CBFV step response. The effect of age and breathing manoeuvre on the SNR was assessed using a two-way analysis of variance (ANOVA), whilst the effect of sex was investigated using a Student's t test. No significant differences were observed in SNR (baseline 6.07 ± 3.07 dB and 7.33 ± 3.84 dB, breath-hold: 13.53 ± 3.93 dB and 14.64 ± 4.52 dB, and hyperventilation: 14.69 ± 4.04 dB and 14.84 ± 4.05 dB) estimates between young and old groups, respectively. The use of breathing manoeuvres significantly improved the SNR (p < 10(-4)) without a significant difference between manoeuvres. Sex does not appear to have an effect on SNR (p = 0.365). Coherence estimates were not influenced by the SNR, but significant differences were found in the amplitude of the CBFV step response. Copyright © 2011 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Interventions to improve cardiopulmonary hemodynamics during laparoscopy in a porcine sepsis model.

PubMed

Grief, W M; Forse, R A

1999-11-01

Laparoscopy is increasingly used in severely ill and acutely septic patients. In animals undergoing laparoscopy, the hemodynamic response to sepsis is blunted. Specific interventions to augment the hemodynamic potential may make laparoscopic intervention a safer alternative in septic patients. We compared different interventions to improve hemodynamic performance during exploratory laparoscopy in a porcine endotoxic shock model. Domestic pigs (n = 12) received intravenous lipopolysaccharide injection and underwent surgical abdominal exploration using either laparoscopy or conventional laparotomy. For comparison, pigs exposed to endotoxin underwent laparoscopy with these interventions: intravenous infusions of prostacyclin (n = 5) or indomethacin (n = 4), intravenous crystalloid resuscitation (n = 5), pulmonary hyperventilation (n = 4), or abdominal insufflation with air (n = 5). Hemodynamic measurements and blood gas analyses were obtained using Swan-Ganz and arterial catheters. Septic animals treated with prostacyclin undergoing laparoscopy had a higher cardiac index (CI, p < 0.01), stroke volume (SV; p < 0.001) and oxygen delivery (p < 0.05) than the untreated group. Likewise, treatment with indomethacin was associated with a higher CI (p < 0.001), SV (p < 0.005), and oxygen delivery (p < 0.005) compared with the untreated group. These effects may be secondary to a decreased pulmonary vascular resistance, demonstrated in the animals that received either prostacyclin (p < 0.05) or indomethacin (p < 0.05). In addition, animals given aggressive fluid resuscitation had a significantly higher CI (p < 0.05) and SV (p < 0.001) than those with normal fluid resuscitation during laparoscopy. Manipulation of arterial pH by insufflation of the abdomen with air to create the pneumoperitoneum, or by aggressively hyperventilating the animals, did not improve CI. Adverse effects of laparoscopy on cardiovascular hemodynamics in the septic state may be mediated by increased pulmonary vascular resistance, diminished venous return, or both. Specific interventions to reverse these variables may ameliorate hemodynamic changes seen.

Physiological responses to heat of resting man with impaired sweating capacity

NASA Technical Reports Server (NTRS)

Totel, G. L.

1974-01-01

The effects of total-body heat exposure were studied in three groups of subjects with varied degrees of impaired sweating capacity. The responses of two ectodermal dysplasic men, six quadriplegic men, and a man with widespread burned scar tissue were compared with the responses of three able-bodied men resting in the heat. It was found that the able-bodied and burned subjects competed successfully with a controlled environment of 38 C and 20% relative humidity for up to 150 min, whereas the quadriplegic and ectodermal dysplasic men developed hyperthermia, hyperventilation, and distress after only 120 and 75 min of heat exposure, respectively. The intolerance to heat is thus ascribed directly to the inability to produce and evaporate sweat.

Mental disorders induced by carbamazepine.

PubMed

Mizukami, K; Naito, Y; Yoshida, M; Nakanishi, T; Koizumi, J

1990-03-01

We present here a case with various physical and neuropsychiatric symptoms caused by the administration of carbamazepine. The patient suffering from right ophthalmic neuralgia showed fever, eczema, erythema, lymphoadenopathy, eosinophilia, vomiting, headache, dizziness, nystagmus, and various mental disorders which consisted of emotional instability, personality change, delusions of reference and persecution, depressive state, and hyperventilation syndrome during the administration of carbamazepine. The physical symptoms in the present case were conformable to the side effect of carbamazepine. The mental disorders appeared in a few days from the start of carbamazepine administration and disappeared after the discontinuation of the administration of this drug without antipsychotic therapy and have never relapsed until now. The mental disorders and the physical symptoms were in parallel with their clinical course. This kind of mental disorders induced by carbamazepine has not yet been reported.

Monitoring of rapid blood pH variations by CO detection in breath with tunable diode laser

NASA Astrophysics Data System (ADS)

Kouznetsov, Andrian I.; Stepanov, Eugene V.; Zyrianov, Pavel V.; Shulagin, Yurii A.; Diachenko, Alexander I.; Gurfinkel, Youri I.

1997-06-01

Detection of endogenous carbon monoxide content in breath with tunable diode lasers (TDL) was proposed for noninvasive monitoring of rapid blood pH variation. Applied approach is based on high sensitivity of the haemoglobin and myoglobin affinity for CO to blood pH value and an ability to detect rapidly small variations of CO content in expired air. Breath CO absorption in 4.7 micrometers spectral region was carefully measured using PbSSe tunable diode laser that can provide 1 ppb CO concentration sensitivity and 10 s time constant. Applied TDL gas analyzer was used to monitor expired air of studied persons in physiological tests including hyperventilation and physical load. Simultaneous blood tests were conducted to demonstrate correlation between blood and breath chemical parameters.

Anterior cerebral blood velocity and end-tidal CO2 responses to exercise differ in children and adults.

PubMed

Ellis, Lindsay A; Ainslie, Philip N; Armstrong, Victoria A; Morris, Laura E; Simair, Ryan G; Sletten, Nathan R; Tallon, Christine M; McManus, Ali M

2017-06-01

Little is known about the response of the cerebrovasculature to acute exercise in children and how these responses might differ with adults. Therefore, we compared changes in middle cerebral artery blood velocity (MCAV mean ), end-tidal Pco 2 ([Formula: see text]), blood pressure, and minute ventilation (V̇e) in response to incremental exercise between children and adults. Thirteen children [age: 9 ± 1 (SD) yr] and thirteen sex-matched adults (age: 25 ± 4 yr) completed a maximal exercise test, during which MCAV mean , [Formula: see text], and V̇e were measured continuously. These variables were measured at rest, at exercise intensities specific to individual ventilatory thresholds, and at maximum. Although MCAV mean was higher at rest in children compared with adults, there were smaller increases in children (1-12%) compared with adults (12-25%) at all exercise intensities. There were alterations in [Formula: see text] with exercise intensity in an age-dependent manner [ F (2.5,54.5) = 7.983, P < 0.001; η 2 = 0.266], remaining stable in children with increasing exercise intensity (37-39 mmHg; P > 0.05) until hyperventilation-induced reductions following the respiratory compensation point. In adults, [Formula: see text] increased with exercise intensity (36-45 mmHg, P < 0.05) until the ventilatory threshold. From the ventilatory threshold to maximum, adults showed a greater hyperventilation-induced hypocapnia than children. These findings show that the relative increase in MCAV mean during exercise was attenuated in children compared with adults. There was also a weaker relationship between MCAV mean and [Formula: see text] during exercise in children, suggesting that cerebral perfusion may be regulated by different mechanisms during exercise in the child. NEW & NOTEWORTHY These findings provide the first direct evidence that exercise increases cerebral blood flow in children to a lesser extent than in adults. Changes in end-tidal CO 2 parallel changes in cerebral perfusion in adults but not in children, suggesting age-dependent regulatory mechanisms of cerebral blood flow during exercise. Copyright © 2017 the American Physiological Society.

Diurnal variation in the control of ventilation in response to rising body temperature during exercise in the heat.

PubMed

Tsuji, Bun; Honda, Yasushi; Kondo, Narihiko; Nishiyasu, Takeshi

2016-08-01

We investigated whether heat-induced hyperventilation during exercise is affected by time of day, as diurnal variation leads to higher core temperatures in the evening. Nineteen male subjects were divided into two experiments (protocol 1, n = 10 and protocol 2, n = 9). In protocol 1, subjects performed cycle exercise at 50% peak oxygen uptake in the heat (37°C and 50% RH) in the morning (0600) and evening (1800). Results showed that baseline resting and exercising esophageal temperature (Tes) were significantly (0.5°C) higher in the evening than morning. Minute ventilation (V̇e) increased from 54.3 ± 7.9 and 54.9 ± 6.8 l/min at 10 min to 71.4 ± 8.1 and 76.5 ± 11.8 l/min at 48.5 min in the morning and evening, respectively (both P < 0.01). Time of day had no effect on V̇e (P = 0.44). When V̇e as the output response was plotted against Tes as thermal input, the Tes threshold for increases in V̇e was higher in the evening than morning (37.2 ± 0.7 vs. 36.6 ± 0.6°C, P = 0.009), indicating the ventilatory response to the same core temperature is smaller in the evening. In protocol 2, the circadian rhythm-related higher resting Tes seen in the evening was adjusted down to the same temperature seen in the morning by immersing the subject in cold water. Importantly, the time course of changes in V̇e during exercise were smaller in the evening, but the threshold for V̇e remained higher in the evening than morning (P < 0.001). Collectively, those results suggest that time of day has no effect on time course hyperventilation during exercise in the heat, despite the higher core temperatures in the evening. This is likely due to diurnal variation in the control of ventilation in response to rising core temperature. Copyright © 2016 the American Physiological Society.

Termination of respiratory events with and without cortical arousal in obstructive sleep apnea.

PubMed

Jordan, Amy S; Eckert, Danny J; Wellman, Andrew; Trinder, John A; Malhotra, Atul; White, David P

2011-11-15

A total of 20-30% of respiratory events in obstructive sleep apnea are terminated without clear arousal. Arousals are thought to predispose to further events by promoting hyperventilation, hypocapnia, and upper-airway dilator muscle hypotonia. Therefore, events terminated without arousal may promote stable breathing. To compare physiologic changes at respiratory event termination with American Sleep Disorders Association (ASDA) Arousal to No Arousal, and determine whether secondary respiratory events are less common and have higher dilator muscle activity after No Arousal compared with ASDA Arousal. Patients with obstructive sleep apnea wore sleep staging, genioglossus (EMG(GG)), and tensor palatini (EMG(TP)) electrodes plus a nasal mask and pneumotachograph. During stable sleep, continuous positive airway pressure (CPAP) was lowered for 3-minute periods to induce respiratory events. Physiologic variables were compared between events terminated with (1) ASDA Arousal, (2) No Arousal, or (3) sudden CPAP increase (CPAPinc, control). Sixteen subjects had adequate data. EMG(GG), EMG(TP), and heart rate increased after ASDA Arousal (340 ± 57%, 215 ± 28%, and 110.7 ± 2.3%) and No Arousal (185 ± 32%, 167 ± 15%, and 108.5 ± 1.6%) but not CPAPinc (90 ± 10%, 94 ± 11%, and 102.1 ± 1%). Ventilation increased more after ASDA Arousal than No Arousal and CPAPinc, but not after accounting for the severity of respiratory event. Fewer No Arousals were followed by secondary events than ASDA Arousals. However, low dilator muscle activity did not occur after ASDA Arousal or No Arousal (EMG(GG) rose from 75 ± 5 to 125 ± 7%) and secondary events were less severe than initial events (ventilation rose 4 ± 0.4 to 5.5 ± 0.51 L/min). Respiratory events that were terminated with ASDA Arousal were more severely flow-limited, had enhanced hyperventilation after event termination, and were more often followed by secondary events than No arousal. However, secondary events were not associated with low dilator muscle activity and airflow was improved after both No Arousal and ASDA Arousal.

Termination of Respiratory Events with and without Cortical Arousal in Obstructive Sleep Apnea

PubMed Central

Eckert, Danny J.; Wellman, Andrew; Trinder, John A.; Malhotra, Atul; White, David P.

2011-01-01

Rationale: A total of 20–30% of respiratory events in obstructive sleep apnea are terminated without clear arousal. Arousals are thought to predispose to further events by promoting hyperventilation, hypocapnia, and upper-airway dilator muscle hypotonia. Therefore, events terminated without arousal may promote stable breathing. Objectives: To compare physiologic changes at respiratory event termination with American Sleep Disorders Association (ASDA) Arousal to No Arousal, and determine whether secondary respiratory events are less common and have higher dilator muscle activity after No Arousal compared with ASDA Arousal. Methods: Patients with obstructive sleep apnea wore sleep staging, genioglossus (EMGGG), and tensor palatini (EMGTP) electrodes plus a nasal mask and pneumotachograph. During stable sleep, continuous positive airway pressure (CPAP) was lowered for 3-minute periods to induce respiratory events. Physiologic variables were compared between events terminated with (1) ASDA Arousal, (2) No Arousal, or (3) sudden CPAP increase (CPAPinc, control). Measurements and Main Results: Sixteen subjects had adequate data. EMGGG, EMGTP, and heart rate increased after ASDA Arousal (340 ± 57%, 215 ± 28%, and 110.7 ± 2.3%) and No Arousal (185 ± 32%, 167 ± 15%, and 108.5 ± 1.6%) but not CPAPinc (90 ± 10%, 94 ± 11%, and 102.1 ± 1%). Ventilation increased more after ASDA Arousal than No Arousal and CPAPinc, but not after accounting for the severity of respiratory event. Fewer No Arousals were followed by secondary events than ASDA Arousals. However, low dilator muscle activity did not occur after ASDA Arousal or No Arousal (EMGGG rose from 75 ± 5 to 125 ± 7%) and secondary events were less severe than initial events (ventilation rose 4 ± 0.4 to 5.5 ± 0.51 L/min). Conclusions: Respiratory events that were terminated with ASDA Arousal were more severely flow-limited, had enhanced hyperventilation after event termination, and were more often followed by secondary events than No arousal. However, secondary events were not associated with low dilator muscle activity and airflow was improved after both No Arousal and ASDA Arousal. PMID:21836132

Efficiency and limitations of the upper airway mucosa as an air conditioner evaluated from the mechanisms of bronchoconstriction in asthmatic subjects.

PubMed

Konno, A; Terada, N; Okamoto, Y; Togawa, K

1985-01-01

To elucidate a limit to the efficiency of the upper airway mucosa as an air conditioner, the temperatures of the inspiratory air and mucosa were measured in the cervical trachea. Both of them were affected only minimally by change of atmospheric air temperature during resting nose breathing, but were affected greatly by change of mode of breathing. During hyperventilation through the mouth, when the atmospheric air temperature was 1 degree C, a temperature difference of 9 degrees C was noted between inspiratory air in the cervical trachea and body temperature, together with a mucosal temperature fall by 1.86 +/- 0.61 degree C. Wearing of a mask caused a rise of 3 degrees C in the inspiratory air temperature in the cervical trachea.

Use of sodium bicarbonate to treat tricyclic antidepressant-induced arrhythmias in a patient with alkalosis.

PubMed Central

Molloy, D W; Penner, S B; Rabson, J; Hall, K W

1984-01-01

Sodium bicarbonate has been recommended for the treatment of arrhythmias induced by tricyclic antidepressants. It is unclear, however, whether this therapy is effective only in the presence of acidosis. A case is presented in which there was an immediate response to sodium bicarbonate in three episodes of ventricular tachycardia despite the presence of alkalosis on two of the three occasions. Given the poor response to conventional therapy of arrhythmias induced by tricyclic antidepressants the use of sodium bicarbonate may be reasonable even in the presence of alkalosis. However, in the presence of pre-existing respiratory or metabolic alkalosis, such therapy is not without risk, and it is suggested that it be reserved for life-threatening situations when the arrhythmia has failed to respond to hyperventilation or antiarrhythmics or both. PMID:6329501

Persistent pulmonary hypertension of the newborn.

PubMed

Nair, P M C; Bataclan, Maria Flordeliz A

2004-06-01

This article attempts to define a complicated, yet not rare disease of the neonate, which presents with extreme hypoxemia due to increased pulmonary vascular resistance, resulting in diversion of the pulmonary venous blood through persistent fetal channels, namely ductus arteriosus and foramen ovale. Pathophysiology, diagnostic approach and the various modalities of management are analyzed. Persistent pulmonary hypertension of the newborn is multi-factorial, which is reflected in the management as well. These babies are extremely labile to hypoxia and should be stabilized with minimum handling. One hundred percent oxygen and ventilation are the mainstay of treatment. The role of hyperventilation, alkalinization, various non-specific vasodilators such as tolazoline, magnesium sulphate, selective vasodilators such as inhaled nitric oxide, adenosine and the role of high frequency oscillatory ventilation and extra corporeal membrane oxygenation are discussed. With the newer modalities of management, the outlook has improved with mortality of less than 20% and fewer long-term deficits.

Peripheral muscle ergoreceptors and ventilatory response during exercise recovery in heart failure.

PubMed

Francis, N; Cohen-Solal, A; Logeart, D

1999-03-01

Recent studies have suggested that the increased ventilatory response during exercise in patients with chronic heart failure was related to the activation of muscle metaboreceptors. To address this issue, 23 patients with heart failure and 7 normal subjects performed arm and leg bicycle exercises with and without cuff inflation around the arms or the thighs during recovery. Obstruction slightly reduced ventilation and gas exchange variables at recovery but did not change the kinetics of recovery of these parameters compared with nonobstructed recovery: half-time of ventilation recovery was 175 +/- 54 to 176 +/- 40 s in patients and 155 +/- 66 to 127 +/- 13 s in controls (P < 0.05, patients vs. controls, not significant within each group from baseline to obstructed recovery). We conclude that muscle metaboreceptor activation does not seem to play a role in the exertion hyperventilation of patients with heart failure.

Near-infrared measurements of hemodynamic and oxygenation changes on the frontal cortex during breath holding, hyperventilation, and natural sleep

NASA Astrophysics Data System (ADS)

Noponen, Tommi E.; Kotilahti, Kalle; Toppila, Jussi; Nissila, Ilkka T.; Salmi, Tapani; Kajava, Timo T.; Katila, Toivo E.

2003-07-01

We have developed a frequency-domain near-infrared device suitable for physiological studies in human. In this work, a four-channel configuration of the instrument is applied to monitor hemodynamic and oxygenation changes in the frontal cortex of volunteers during different ventilation tasks. We use four different source-receiver separations (2, 3, 4, and 5 cm) and three wavelengths (760, 808, and 830 nm) to test the sensitivity of these parameters to cardiovascular and metabolic changes. Low-frequency oscillations (~ 0.02 Hz) and variations in heart rate during different ventilation tasks are investigated as well. We also study physiological changes during natural sleep using the frequency-domain instrument simultaneously with a polysomnography system containing a pulse oximeter. Our results indicate that hemodynamic and oxygenation changes in the frontal cortex during natural sleep can be detected using near-infrared measurements.

Relationship between central sleep apnea and Cheyne-Stokes Respiration.

PubMed

Flinta, Irena; Ponikowski, Piotr

2016-03-01

Central sleep apnea (CSA) in patients with heart failure (HF) occurs frequently and shows a serious influence on prognosis in this population. The key elements in the pathophysiology of CSA are respiratory instability with chronic hyperventilation, changes of arterial carbon dioxide pressure (pCO2) and elongated circulation time. The main manifestation of CSA in patients with HF is Cheyne-Stokes Respiration (CSR). The initial treatment is the optimization of HF therapy. However, many other options of the therapeutic management have been studied, particularly those based on positive airway pressure methods. In patients with heart failure we often can observe the overlap of CSA and CSR; we will discuss the differences between these forms of breathing disorders during sleep. We will also discuss when CSA and CSR occur independently of each other and the importance of CSR occurring during the daytime in context of CSA during the nighttime. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Analysis of non-invasive FBG sensor for monitoring patient vital signs during MRI

NASA Astrophysics Data System (ADS)

Nedoma, Jan; Fajkus, Marcel; Martinek, Radek; Vasinek, Vladimir

2017-10-01

This article focuses on the analysis and verification of a non-invasive fiber Bragg grating (FBG) sensor used for the monitoring of a patient`s heart rate (HR) and respiratory rate (RR) in a magnetic resonance environment (MRI). Measuring heart and respiratory rate were carried out on a group of five volunteers with their written consent during MRI examinations. The type of the scanner used in the experiment was GE Signa HDxt 1.5T. The benefit of this article lies in the design of a sensor in the form of a sensor pad. The sensor is placed beneath a patient`s body lying supine. The purpose is to increase and improve the patient`s safety as well as to help doctors to predict panic and hyperventilation attacks of patients during MRI examinations. Provided Bland-Altman statistical analysis demonstrates the heart and respiratory rate detection with a satisfactory accuracy for all five volunteers.

Disturbances of Pulmonary Function in Mitral Valve Disease

PubMed Central

Palmer, Wilfred H.; Gee, J. B. L.; Mills, F. C.; Bates, D. V.

1963-01-01

To study the sequence of changes in respiratory function that occur in the natural history of mitral stenosis, and the physiological basis of “cardiac dyspnea”, 30 patients with chronic mitral valve disease were subjected to detailed pulmonary function tests. There was no significant change in vital capacity and functional residual capacity. The reduction in maximal mid-expiratory flow rate showed excellent correlation with the respiratory symptoms. The pulmonary capillary blood volume was increased in moderately advanced cases but was consistently reduced in the severest cases. Hyperventilation was due to an increased respiratory rate. Dyspnea was associated with increased respiratory work owing to the interrelation between the reduction in diffusion capacity, compliance, cardiac output, the increase in airway resistance, and the uneven ventilation and perfusion of the lungs. The amount of “effort” required to breathe is incommensurate with the external load in these patients. PMID:14060164

Electroencephalography in the Diagnosis of Genetic Generalized Epilepsy Syndromes

PubMed Central

Seneviratne, Udaya; Cook, Mark J.; D’Souza, Wendyl Jude

2017-01-01

Genetic generalized epilepsy (GGE) consists of several syndromes diagnosed and classified on the basis of clinical features and electroencephalographic (EEG) abnormalities. The main EEG feature of GGE is bilateral, synchronous, symmetric, and generalized spike-wave complex. Other classic EEG abnormalities are polyspikes, epileptiform K-complexes and sleep spindles, polyspike-wave discharges, occipital intermittent rhythmic delta activity, eye-closure sensitivity, fixation-off sensitivity, and photoparoxysmal response. However, admixed with typical changes, atypical epileptiform discharges are also commonly seen in GGE. There are circadian variations of generalized epileptiform discharges. Sleep, sleep deprivation, hyperventilation, intermittent photic stimulation, eye closure, and fixation-off are often used as activation techniques to increase the diagnostic yield of EEG recordings. Reflex seizure-related EEG abnormalities can be elicited by the use of triggers such as cognitive tasks and pattern stimulation during the EEG recording in selected patients. Distinct electrographic abnormalities to help classification can be identified among different electroclinical syndromes. PMID:28993753

Paresthesias Among Community Members Exposed to the World Trade Center Disaster

PubMed Central

Marmor, Michael; Shao, Yongzhao; Bhatt, D. Harshad; Stecker, Mark M.; Berger, Kenneth I.; Goldring, Roberta M.; Rosen, Rebecca L.; Caplan-Shaw, Caralee; Kazeros, Angeliki; Pradhan, Deepak; Wilkenfeld, Marc; Reibman, Joan

2017-01-01

Objective: Paresthesias can result from metabolic disorders, nerve entrapment following repetitive motions, hyperventilation pursuant to anxiety, or exposure to neurotoxins. We analyzed data from community members exposed to the World Trade Center (WTC) disaster of September 11, 2001, to evaluate whether exposure to the disaster was associated with paresthesias. Methods: Analysis of data from 3141 patients of the WTC Environmental Health Center. Results: Fifty-six percent of patients reported paresthesias at enrollment 7 to 15 years following the WTC disaster. After controlling for potential confounders, paresthesias were associated with severity of exposure to the WTC dust cloud and working in a job requiring cleaning of WTC dust. Conclusions: This study suggests that paresthesias were commonly associated with WTC-related exposures or post-WTC cleaning work. Further studies should objectively characterize these paresthesias and seek to identify relevant neurotoxins or paresthesia-inducing activities. PMID:28157767

Respiratory alkalosis.

PubMed

Foster, G T; Vaziri, N D; Sassoon, C S

2001-04-01

Respiratory alkalosis is an extremely common and complicated problem affecting virtually every organ system in the body. This article reviews the various facets of this interesting problem. Respiratory alkalosis produces multiple metabolic abnormalities, from changes in potassium, phosphate, and calcium, to the development of a mild lactic acidosis. Renal handling of the above ions is also affected. The etiologies may be related to pulmonary or extrapulmonary disorders. Hyperventilation syndrome is a common etiology of respiratory alkalosis in the emergency department setting and is a diagnosis by exclusion. There are many cardiac effects of respiratory alkalosis, such as tachycardia, ventricular and atrial arrhythmias, and ischemic and nonischemic chest pain. In the lungs, vasodilation occurs, and in the gastrointestinal system there are changes in perfusion, motility, and electrolyte handling. Therapeutically, respiratory alkalosis is used for treatment of elevated intracranial pressure. Correction of a respiratory alkalosis is best performed by correcting the underlying etiology.

Exogenous factors in panic disorder: clinical and research implications.

PubMed

Roy-Byrne, P P; Uhde, T W

1988-02-01

Because panic disorder has an underlying biologic and probably genetic basis, the role of factors outside the organism in initiating and sustaining panic is often overlooked. The authors review certain exogenous factors that seem capable of triggering attacks and/or increasing their frequency and intensity: self-administered pharmacologic agents (caffeine, alcohol, nicotine, over-the-counter cold preparations, cannabis, cocaine); habits (sleep deprivation, diet, exercise, relaxation, hyperventilation); and aspects of the environment (fluorescent lighting, life stressors). There may be a specificity to the action of some of these factors, because certain factors previously thought to trigger panic attacks (e.g., pain, hypoglycemia) have been proved not to have this effect. Although the clinical significance of many of the exogenous factors discussed still awaits empirical confirmation, attention to such factors during the initial evaluation of a patient with panic disorder may be helpful in formulating a successful treatment plan.

Time-Frequency Characterization of Cerebral Hemodynamics of Migraine Sufferers as Assessed by NIRS Signals

NASA Astrophysics Data System (ADS)

Molinari, Filippo; Rosati, Samanta; Liboni, William; Negri, Emanuela; Mana, Ornella; Allais, Gianni; Benedetto, Chiara

2010-12-01

Near-infrared spectroscopy (NIRS) is a noninvasive system for the real-time monitoring of the concentration of oxygenated ([InlineEquation not available: see fulltext.]) and reduced (HHb) hemoglobin in the brain cortex. [InlineEquation not available: see fulltext.] and HHb concentrations vary in response to cerebral autoregulation. Sixty-eight women (14 migraineurs without aura, 49 migraineurs with aura, and 5 controls) performed breath-holding and hyperventilation during NIRS recordings. Signals were processed using the Choi-Williams time-frequency transform in order to measure the power variation of the very-low frequencies (VLF: 20-40 mHz) and of the low frequencies (LF: 40-140 mHz). Results showed that migraineurs without aura present different LF and VLF power levels than controls and migraineurs with aura. The accurate power measurement of the time-frequency analysis allowed for the discrimination of the subjects' hemodynamic patterns. The time-frequency analysis of NIRS signals can be used in clinical practice to assess cerebral hemodynamics.

Hemodynamic, ventilatory, and biochemical responses of panic patients and normal controls with sodium lactate infusion and spontaneous panic attacks.

PubMed

Gaffney, F A; Fenton, B J; Lane, L D; Lake, C R

1988-01-01

Hemodynamic, ventilatory, and biochemical variables were measured in ten healthy adults and ten panic patients during infusion of 0.5 mol/L of sodium lactate. Physical activity, fitness level, and ambulatory electrocardiograms were also recorded. Lactate infusion doubled cardiac output, increased blood lactate levels by sixfold, and produced hypernatremia, hypocalcemia, and decreased serum bicarbonate levels in both groups but raised arterial pressure only in the patients. The patients hyperventilated before and during the infusion. Physiological responses and somatic complaints with the infusion differed little between the groups, but emotional complaints were six times more frequent among the panic patients. Eight patients but no control subjects interpreted their symptoms as a panic attack. Heart rate increased with only 14 of 31 recorded spontaneous outpatient panic attacks. Sodium lactate infusions appear to produce panic by mimicking the physiology of spontaneous panic. Treatment with cardioactive agents is not indicated in the absence of cardiopulmonary or autonomic nervous system abnormalities.

Tetany: quantitative interrelationships between calcium and alkalosis.

PubMed

Edmondson, J W; Brashear, R E; Li, T K

1975-04-01

Tetany occurs with hypocalcemia and alkalosis or both. The interrelationship of calcium and acid-base balance necessary for inducing tetany, the role of the central nervous system, and the rate of development of hypocalcemia have been investigated. Tetany occurred in less than 50 percent of one group of dogs made alkalotic by hyperventilation or made hypocalcemic by infusion of ethylene glycol-bis(beta-amino ethyl ether) N, N'-tetraacetate. In contrast, hypocalcemia combined with hypocapnic alkalosis always produced tetany. Slowly evolving hypocalcemia was achieved inanother group of dogs by thyroparathyroidectomy, and tetany was induced postoperatively by hypocapnic alkalosis. An identical relationship between serum calcium ion concentration and arterial pH or CO2 tension was found in both groups. Tetany could not be related to the cerebrospinal fluid (CSF) calcium ion content in either group. Hypocalcemia and alkalosis are therefore coparticipants in the development of tetany and are independent of the rate of development of hypocalcemia and of CSF calcium ion concentration. The importance of alkalosis in tetany with hypoparathyroidism is emphasized.

Contemporary Insights and Novel Treatment Approaches to Central Sleep Apnea Syndrome in Heart Failure

PubMed Central

Grayburn, Ryan L.; Kaka, Yaquta; Wilson Tang, W. H.

2014-01-01

Opinion Statement Central sleep apnea (CSA) is a common and under-diagnosed condition commonly associated with Cheyne-Stokes respiration. It is particularly prevalent in the heart failure population affecting up to 40% of all patients with heart failure. The pathophysiology associated with CSA is based on the underlying effects of hypoventilation and hyperventilation, with neurologic dysregulation of respiratory control as the primary defect. However, therapeutic options are limited due to the prevailing perception that CSA is a consequence, rather than cause of morbidity and mortality. At present, the main focus remains treating the underlying problem (ie intensifying heart failure therapeutics, decongestion), while additional suggestions of using acetazolamide, progesterone, nocturnal oxygen, and theophylline have not been validated with contemporary clinical trials. Positive pressure ventilation is currently the primary recommendation for all patients with sleep-disordered breathing (CSA included), and in some patients may effectively reduce the apnea-hypopnea index. However, significant research is ongoing to determine how to treat this complex patient population. PMID:24874028

Common High Altitudes Illnesses a Primer for Healthcare Provider

PubMed Central

Mohsenin, Vahid

2015-01-01

Exposure to high altitude imposes significant strain on cardiopulmonary system and the brain. As a consequence, sojourners to high altitude frequently experience sleep disturbances, often reporting restless and sleepless nights. At altitudes above 3,000 meters (9,800 ft) almost all healthy subjects develop periodic breathing especially during NREM sleep. Sleep architecture gradually improves with increased NREM and REM sleep despite persistence of periodic breathing. The primary reason for periodic breathing at high altitude is a hypoxic-induced increase in chemoreceptor sensitivity to changes in PaCO2 – both above and below eupnea, leading to periods of apnea and hyperpnea. Acetazolamide improves sleep by reducing the periodic breathing through development of metabolic acidosis and induced hyperventilation decreasing the plant gain and widening the PCO2 reserve. This widening of the PCO2 reserve impedes development of central apneas during sleep. Benzodiazepines and GABA receptor antagonist such as zolpidem improve sleep without affecting breathing pattern or cognitive functions. PMID:27057512

The ins and outs of breath holding: simple demonstrations of complex respiratory physiology.

PubMed

Skow, Rachel J; Day, Trevor A; Fuller, Jonathan E; Bruce, Christina D; Steinback, Craig D

2015-09-01

The physiology of breath holding is complex, and voluntary breath-hold duration is affected by many factors, including practice, psychology, respiratory chemoreflexes, and lung stretch. In this activity, we outline a number of simple laboratory activities or classroom demonstrations that illustrate the complexity of the integrative physiology behind breath-hold duration. These activities require minimal equipment and are easily adapted to small-group demonstrations or a larger-group inquiry format where students can design a protocol and collect and analyze data from their classmates. Specifically, breath-hold duration is measured during a number of maneuvers, including after end expiration, end inspiration, voluntary prior hyperventilation, and inspired hyperoxia. Further activities illustrate the potential contribution of chemoreflexes through rebreathing and repeated rebreathing after a maximum breath hold. The outcome measures resulting from each intervention are easily visualized and plotted and can comprise a comprehensive data set to illustrate and discuss complex and integrated cardiorespiratory physiology. Copyright © 2015 The American Physiological Society.

Hypophosphatemia in Users of Cannabis.

PubMed

Cadman, Peter E

2017-01-01

As cannabis use has legalized for medical and recreational use in several states, the medical community has become more aware of the drug's potential toxicities. First described in 2004, cannabinoid hyperemesis syndrome is increasingly recognized as a cause of hospitalization among drug users. However, little information is available in the medical literature regarding electrolyte abnormalities in this syndrome. Between 2011 and 2014, six men were treated for cannabinoid hyperemesis syndrome at the Veterans Affairs Medical Center in San Diego, CA, and found to have significant hypophosphatemia (phosphate range, <1-1.3mg/dL). The 6 cases are presented here and possible causes of hypophosphatemia are discussed. In 3 patients, serum phosphate levels normalized spontaneously within hours, suggesting redistribution of phosphate as a potential mechanism. Hyperventilation, which can lead to phosphate redistribution, was observed in 4 of the 6 individuals and may have contributed. Hypophosphatemia is a presenting feature of cannabinoid hyperemesis syndrome in some patients. Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

[Temporary disappearance of EEG activity during reversible respiratory failure in rabbits and cats].

PubMed

Jurco, M; Tomori, Z; Tkácová, R; Calfa, J

1989-02-01

The dynamics of changes of EEG activity was studied on the model of reversible respiratory failure in rabbits and cats in pentobarbital anesthesia. During N2 inhalation, apnea of 60 second duration, and subsequent resuscitation the electrocorticogram in bifrontal and bioccipital connection was recorded. Evaluation of 19 episodes of apnea in 7 rabbits and of 25 episodes in 8 cats yielded the following results: 1. During hyperventilation induced by N2 inhalation a certain activation of the EEG was observed (spindles more pronounced, increased occurrence rate of discharges of the reticular activation system). 2. At the onset of apnea the EEG was still distinct, suggesting that primary apnea is presumably not caused by anoxia and the accompanying electric silence of the structures that control respiration. 3. Disappearance of EEG occurred within 50 seconds from the onset of apnea in rabbits and within 30 seconds in cats. 4. After repeated episodes of apnea lasting for 60 sec., artificial ventilation mostly resulted in normalization of EEG.

Increased erythropoietin concentration after repeated apneas in humans.

PubMed

de Bruijn, Robert; Richardson, Matt; Schagatay, Erika

2008-03-01

Hypoxia-induced increases in red blood cell production have been found in both altitude-adapted populations and acclimatized lowlanders. This process is mediated by erythropoietin (EPO) released mainly by the hypoxic kidney. We have previously observed high hemoglobin concentrations in elite breath-hold divers and our aim was to investigate whether apnea-induced hypoxia could increase EPO concentration. Ten healthy volunteers performed 15 maximal duration apneas, divided into three series of five apneas, each series separated by 10 min of rest. Apneas within series were separated by 2 min and preceded by 1 min of hyperventilation to increase apnea duration and arterial oxygen desaturation. When EPO concentration after serial apneas was compared to baseline values, an average maximum increase of 24% was found (P < 0.01). No changes in EPO concentration were observed during a control day without apnea, eliminating possible effects of a diurnal rhythm or blood loss. We therefore conclude that serial apneas increase circulating EPO concentration in humans.

Evaluation of cerebral maturation by visual and quantitative analysis of resting electroencephalography in children with primary nocturnal enuresis.

PubMed

Hallioğlu, O; Ozge, A; Comelekoglu, U; Topaloglu, A K; Kanik, A; Duzovali, O; Yilgor, E

2001-10-01

This study was undertaken to evaluate resting electroencephalographic (EEG) changes and their relations to cerebral maturation in children with primary nocturnal enuresis. Cerebral maturation is known to be important in the pathogenesis of this disorder. Twenty-five right-handed patients with primary nocturnal enuresis, aged 6 to 14 years, and 23 age- and sex-matched healthy children were included in this cross-sectional case-control study. The abnormalities detected using such techniques as hemispheral asymmetry, regional differences, and hyperventilation response in addition to visual and quantitative EEG analysis were examined statistically by multivariate analysis. A decrease in alpha activity in the left (dominant hemisphere) temporal lobe and in the frontal lobes bilaterally and an increase in delta activity in the right temporal region were observed. We concluded that insufficient cerebral maturation is an important factor in the pathogenesis of primary nocturnal enuresis, and EEG, as a noninvasive and inexpensive method, could be used in evaluating cerebral maturation.

Effects of growth, diving history, and high altitude on blood oxygen capacity in harbor seals

NASA Technical Reports Server (NTRS)

Kodama, A. M.; Elsner, R.; Pace, N.

1977-01-01

Blood volume and body composition for diving and nondiving harbor seals were measured at six-week intervals during a 10-month period of captitivity. Whole body hematocrit, red cell volume per kg of lean body mass, and total circulating hemoglobin per kg lean body mass were significantly higher in the diving group, but relatively large blood volumes expressed in terms of body weight (11-12%) were found in both groups. A pair of harbor seals exposed to high altitude for about three months registered significant increases in red cell volume, blood hemoglobin levels, and blood volume expressed in terms of body weight; results of alveolar gas analyses indicate that hyperventilation also occurred. These typical mammalian responses to hypoxia suggest that the harbor seal's large blood volume and high hemoglobin content are an expression of phylogenetic control, and that in spite of its adaptability to apnea during its diving life, the animal cannot be considered preacclimatized to high altitude.

Redox signaling in acute oxygen sensing.

PubMed

Gao, Lin; González-Rodríguez, Patricia; Ortega-Sáenz, Patricia; López-Barneo, José

2017-08-01

Acute oxygen (O 2 ) sensing is essential for individuals to survive under hypoxic conditions. The carotid body (CB) is the main peripheral chemoreceptor, which contains excitable and O 2 -sensitive glomus cells with O 2 -regulated ion channels. Upon exposure to acute hypoxia, inhibition of K + channels is the signal that triggers cell depolarization, transmitter release and activation of sensory fibers that stimulate the brainstem respiratory center to produce hyperventilation. The molecular mechanisms underlying O 2 sensing by glomus cells have, however, remained elusive. Here we discuss recent data demonstrating that ablation of mitochondrial Ndufs2 gene selectively abolishes sensitivity of glomus cells to hypoxia, maintaining responsiveness to hypercapnia or hypoglycemia. These data suggest that reactive oxygen species and NADH generated in mitochondrial complex I during hypoxia are signaling molecules that modulate membrane K + channels. We propose that the structural substrates for acute O 2 sensing in CB glomus cells are "O 2 -sensing microdomains" formed by mitochondria and neighboring K + channels in the plasma membrane. Copyright © 2017. Published by Elsevier B.V.

Pitt-Hopkins Syndrome: A Review of Current Literature, Clinical Approach, and 23-Patient Case Series.

PubMed

Goodspeed, Kimberly; Newsom, Cassandra; Morris, Mary Ann; Powell, Craig; Evans, Patricia; Golla, Sailaja

2018-03-01

Pitt-Hopkins syndrome (PTHS) is a rare, genetic disorder caused by a molecular variant of TCF4 which is involved in embryologic neuronal differentiation. PTHS is characterized by syndromic facies, psychomotor delay, and intellectual disability. Other associated features include early-onset myopia, seizures, constipation, and hyperventilation-apneic spells. Many also meet criteria for autism spectrum disorder. Here the authors present a series of 23 PTHS patients with molecularly confirmed TCF4 variants and describe 3 unique individuals. The first carries a small deletion but does not exhibit the typical facial features nor the typical pattern of developmental delay. The second exhibits typical facial features, but has attained more advanced motor and verbal skills than other reported cases to date. The third displays typical features of PTHS, however inherited a large chromosomal duplication involving TCF4 from his unaffected father with somatic mosaicism. To the authors' knowledge, this is the first chromosomal duplication case reported to date.

Congenital Lobar Emphysema: An Approach of Anesthetic Management.

PubMed

Mourya, Meenakshi; Meena, Dharam Singh

2016-08-01

Congenital Lobar Emphysema (CLE) is a medical condition which is quiet rarely seen especially in neonates. The disease is characterized by over inflation of lungs which is produced due to inhibition of escape of inspired air from lungs. This condition usually occurs in infants due to partial obstruction of the bronchus and can be reversed with timely and planned anaesthetic management. Here in, we are presenting a case of an infant who was merely four months of age. CLE was affecting his left upper lobe since birth which was being treated as lobar pneumonia outside at some peripheral health center. The case presented to hospital with the symptoms acute respiratory distress and was taken up for urgent surgical management. Left upper lobectomy was performed which relived his symptoms. Case was discharged from hospital after 10 days of uneventful hospital stay. The case was challenging, as it involved careful and planned anaesthetic management of lung separation as well as prevention of hyperventilation of the un-involved lung.

Acclimatization and tolerance to extreme altitude

NASA Technical Reports Server (NTRS)

West, J. B.

1993-01-01

During the last ten years, two major experiments have elucidated the factors determining acclimatization and tolerance to extreme altitude (over 7000 m). These were the American Medical Research Expedition to Everest, and the low pressure chamber simulation, Operation Everest II. Extreme hyperventilation is one of the most important responses to extreme altitude. Its chief value is that it allows the climber to maintain an alveolar PO2 which keeps the arterial PO2 above dangerously low levels. Even so, there is evidence of residual impairment of central nervous system function after ascents to extreme altitude, and maximal oxygen consumption falls precipitously above 7000 m. The term 'acclimatization' is probably not appropriate for altitudes above 8000 m, because the body steadily deteriorates at these altitudes. Tolerance to extreme altitude is critically dependent on barometric pressure, and even seasonal changes in pressure probably affect climbing performance near the summit of Mt Everest. Supplementary oxygen always improves exercise tolerance at extreme altitudes, and rescue oxygen should be available on climbing expeditions to 8000 m peaks.

Inhomogeneity of pulmonary perfusion during sustained microgravity

NASA Technical Reports Server (NTRS)

Prisk, G. Kim; Guy, Harold J. B.; Elliott, Ann R.; West, John B.

1994-01-01

The effects of gravity on the inhomogeneity of pulmonary perfusion in man were studied by performing hyperventilation-breathhold single-breath measurements before, during and after 9 days of continuous exposure to microgravity. In microgravity the indicators of inhomogeneity of perfusion, especially the size of cardiogenic oscillations in expired CO2 and the height of phase 4, were both markedly reduced. Cardiogenic oscillations were reduced to approximately 60 of their preflight standing size, while the height of phase 4 was between 0 and -8% (a terminal fall became a small terminal rise) of preflights standing. The terminal change in CO2 was nearly abolished in microgravity indicating more uniformity of blood flow between lung units that close at the end of expiration and units that remain open. This may result from the disappearance of gravity-dependent topographical inequality of blood flow. The residual cardiographic oscillations in expired CO2 imply a persisting inhomogeneity of perfusion in the absence of gravity at a level larger than acinar.

Multifractal and wavelet analysis of epileptic seizures

NASA Astrophysics Data System (ADS)

Dick, Olga E.; Mochovikova, Irina A.

The aim of the study is to develop quantitative parameters of human electroencephalographic (EEG) recordings with epileptic seizures. We used long-lasting recordings from subjects with epilepsy obtained as part of their clinical investigation. The continuous wavelet transform of the EEG segments and the wavelet-transform modulus maxima method enable us to evaluate the energy spectra of the segments, to fin lines of local maximums, to gain the scaling exponents and to construct the singularity spectra. We have shown that the significant increase of the global energy with respect to background and the redistribution of the energy over the frequency range are observed in the patterns involving the epileptic activity. The singularity spectra expand so that the degree of inhomogenety and multifractality of the patterns enhances. Comparing the results gained for the patterns during different functional probes such as open and closed eyes or hyperventilation we demonstrate the high sensitivity of the analyzed parameters (the maximal global energy, the width and asymmetry of the singularity spectrum) for detecting the epileptic patterns.

Case Report: A Case of Severe Cerebral Malaria Managed with Therapeutic Hypothermia and Other Modalities for Brain Edema.

PubMed

Gad, AbdAllah; Ali, Sajjad; Zahoor, Talal; Azarov, Nick

2018-04-01

Malarial infections are uncommon in the United States and almost all reported cases stem from recent travelers coming from endemic countries. Cerebral malaria (CM) is a severe form of the disease usually affecting children and individuals with limited immunity. Despite proper management, mortality from CM can reach up to 25%, especially when it is associated with brain edema. Inefficient management of the edema may result in brain herniation and death. Uniform guidelines for management of CM-associated brain edema are lacking. In this report, we present a case of CM with associated severe brain edema that was successfully managed using a unique combination of therapeutic hypothermia, hypertonic saline, mannitol, and hyperventilation along with the antimalarial drugs quinidine and doxycycline. Our use of hypothermia was based on its proven benefit for improving neurological outcomes in post-cardiac arrest patients and previous in vitro research, suggesting its potential inhibitory role on malaria growth.

Intoxication by cyanide in fires: a study in monkeys using polyacrylonitrile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Purser, D.A.; Grimshaw, P.; Berrill, K.R.

It is suspected that hydrogen cyanide (HCN) may be an important factor in incapacitating fire victims, but the effects of sublethal exposures are not well characterized. Also, the incapacitating effects of fire atmospheres result from exposure to a mixture of toxic products so that the contribution from each component is difficult to determine. The mechanisms of incapacitation in monkeys exposed to the pyrolysis products of polyacrylonitrile (PAN) were compared to those resulting from low level HCN gas exposures. The physiological effects of the PAN atmospheres were almost identical to those of HCN gas alone. They consisted of hyperventilation, followed bymore » loss of consciousness after 1-5 min, bradycardia with arrhythmias and T-wave abnormalities, and were followed by a rapid recovery after exposure. Hydrogen cyanide is considered to be the major toxic product formed by the pyrolysis of PAN. It is suggested that HCN may produce rapid incapacitation at low blood levels of cyanide in fires, while death may occur later due to carbon monoxide poisoning or other factors.« less

Pinpointing brainstem mechanisms responsible for autonomic dysfunction in Rett syndrome: therapeutic perspectives for 5-HT1A agonists

PubMed Central

Abdala, Ana P.; Bissonnette, John M.; Newman-Tancredi, Adrian

2014-01-01

Rett syndrome is a neurological disorder caused by loss of function of methyl-CpG-binding protein 2 (MeCP2). Reduced function of this ubiquitous transcriptional regulator has a devastating effect on the central nervous system. One of the most severe and life-threatening presentations of this syndrome is brainstem dysfunction, which results in autonomic disturbances such as breathing deficits, typified by episodes of breathing cessation intercalated with episodes of hyperventilation or irregular breathing. Defects in numerous neurotransmitter systems have been observed in Rett syndrome both in animal models and patients. Here we dedicate special attention to serotonin due to its role in promoting regular breathing, increasing vagal tone, regulating mood, alleviating Parkinsonian-like symptoms and potential for therapeutic translation. A promising new symptomatic strategy currently focuses on regulation of serotonergic function using highly selective serotonin type 1A (5-HT1A) “biased agonists.” We address this newly emerging therapy for respiratory brainstem dysfunction and challenges for translation with a holistic perspective of Rett syndrome, considering potential mood and motor effects. PMID:24910619

The role of hemoglobin oxygen affinity in oxygen transport at high altitude.

PubMed

Winslow, Robert M

2007-09-30

Hemoglobin is involved in the regulation of O(2) transport in two ways: a long-term adjustment in red cell mass is mediated by erythropoietin (EPO), a response to renal oxgyenation. Short-term, rapid-response adjustments are mediated by ventilation, cardiac output, hemoglobin oxygen affinity (P50), barriers to O(2) diffusion, and the control of local microvascular tissue perfusion. The distribution of O(2) between dissolved (PO2) and hemoglobin-bound (saturation) is the familiar oxygen equilibrium curve, whose position is noted as P50. Human hemoglobin is not genetically adapted for function at high altitude. However, more specialized species native to high altitudes (guinea pig and bar-headed goose, for example) seem to have a lower P50 than their sea level counterparts, an adaptation that presumably promotes O(2) uptake from a hypoxic environment. Humans, native to very high altitude either in the Andes or Himalayan mountains, also can increase O(2) affinity, not because of a fundamental difference in hemoglobin structure or function, but because of extreme hyperventilation and alkalosis.

Task2 potassium channels set central respiratory CO2 and O2 sensitivity

PubMed Central

Gestreau, Christian; Heitzmann, Dirk; Thomas, Joerg; Dubreuil, Véronique; Bandulik, Sascha; Reichold, Markus; Bendahhou, Saïd; Pierson, Patricia; Sterner, Christina; Peyronnet-Roux, Julie; Benfriha, Chérif; Tegtmeier, Ines; Ehnes, Hannah; Georgieff, Michael; Lesage, Florian; Brunet, Jean-Francois; Goridis, Christo; Warth, Richard; Barhanin, Jacques

2010-01-01

Task2 K+ channel expression in the central nervous system is surprisingly restricted to a few brainstem nuclei, including the retrotrapezoid (RTN) region. All Task2-positive RTN neurons were lost in mice bearing a Phox2b mutation that causes the human congenital central hypoventilation syndrome. In plethysmography, Task2−/− mice showed disturbed chemosensory function with hypersensitivity to low CO2 concentrations, leading to hyperventilation. Task2 probably is needed to stabilize the membrane potential of chemoreceptive cells. In addition, Task2−/− mice lost the long-term hypoxia-induced respiratory decrease whereas the acute carotid-body-mediated increase was maintained. The lack of anoxia-induced respiratory depression in the isolated brainstem–spinal cord preparation suggested a central origin of the phenotype. Task2 activation by reactive oxygen species generated during hypoxia could silence RTN neurons, thus contributing to respiratory depression. These data identify Task2 as a determinant of central O2 chemoreception and demonstrate that this phenomenon is due to the activity of a small number of neurons located at the ventral medullary surface. PMID:20133877

The Utility of EEG in Attention Deficit Hyperactivity Disorder: A Replication Study.

PubMed

Swatzyna, Ronald J; Tarnow, Jay D; Roark, Alexandra; Mardick, Jacob

2017-07-01

The routine use of stimulants in pediatrics has increased dramatically over the past 3 decades and the long-term consequences have yet to be fully studied. Since 1978 there have been 7 articles identifying electroencephalogram (EEG) abnormalities, particularly epileptiform discharges in children with attention deficit hyperactivity disorder (ADHD). Many have studied the prevalence of these discharges in this population with varying results. An article published in 2011 suggests that EEG technology should be considered prior to prescribing stimulants to children diagnosed with ADHD due to a high prevalence of epileptiform discharges. The 2011 study found a higher prevalence (26%) of epileptiform discharges when using 23-hour and sleep-deprived EEGs in comparison with other methods of activation (hyperventilation or photostimulation) and conventional EEG. We sought to replicate the 2011 results using conventional EEG with the added qEEG technologies of automatic spike detection and low-resolution electromagnetic tomography analysis (LORETA) brain mapping. Our results showed 32% prevalence of epileptiform discharges, which suggests that an EEG should be considered prior to prescribing stimulant medications.

Abdominal epilepsy as an unusual cause of abdominal pain: a case report.

PubMed

Yunus, Yilmaz; Sefer, Ustebay; Dondu, Ulker Ustebay; Ismail, Ozanli; Yusuf, Ehi

2016-09-01

Abdominal pain, in etiology sometimes difficult to be defined, is a frequent complaint in childhood. Abdominal epilepsy is a rare cause of abdominal pain. In this article, we report on 5 year old girl patient with abdominal epilepsy. Some investigations (stool investigation, routine blood tests, ultrasonography (USG), electrocardiogram (ECHO) and electrocardiograpy (ECG), holter for 24hr.) were done to understand the origin of these complaints; but no abnormalities were found. Finally an EEG was done during an episode of abdominal pain and it was shown that there were generalized spikes especially precipitated by hyperventilation. The patient did well on valproic acid therapy and EEG was normal 1 month after beginning of the treatment. The cause of chronic recurrent paroxymal abdominal pain is difficult for the clinicians to diagnose in childhood. A lot of disease may lead to paroxysmal gastrointestinal symptoms like familial mediterranean fever and porfiria. Abdominal epilepsy is one of the rare but easily treatable cause of abdominal pain. In conclusion, abdominal epilepsy should be suspected in children with recurrent abdominal pain.

Vitamin E does not prevent exercise-induced increase in pulmonary clearance.

PubMed

Lorino, A M; Paul, M; Cocea, L; Scherrer-Crosbie, M; Dahan, E; Meignan, M; Atlan, G

1994-11-01

It has been observed that sustained exercise results in a prolonged increase in alveolar epithelial permeability, as assessed by the pulmonary clearance rate of aerosolized 99mTc-labeled diethylenetriaminepentaacetate (Lorino et al. J. Appl. Physiol. 67: 2055-2059, 1989). The involvement of lipid peroxidation in this increased permeability was tested in seven nonsmoking volunteers by comparing the exercise-induced increases in pulmonary 99mTc-diethylenetriaminepentaacetate clearance before and after a 3-wk supplementation with oral vitamin E (1,000 IU/day), according to a protocol designed as a single-blind crossover study. The 60-min exercise was performed on a treadmill at a constant load corresponding to 80% of maximal O2 uptake. Administration of vitamin E, a very important antioxidant, did not reduce the exercise-induced increase in lung clearance, suggesting that the exercise-induced increase in lung epithelial permeability does not primarily result from the occurrence of lipid peroxidation in the alveolar membrane. This result thus corroborates the hypothesis of an alteration of the intercellular tight junctions due to the mechanical effects of hyperventilation.

[A case of respiratory dyskinesia due to clebopride malate].

PubMed

Kawasaki, H; Yamamoto, M; Okayasu, H; Wakayama, Y

1991-08-01

Clebopride malate is therapeutically used for the treatment of peptic ulcer. This drug has potent antidopaminergic activity that causes acute dystonic reaction, parkinsonism and tardive dyskinesia as adverse effects. Here, we have reported an 86-year-old man who developed abnormal involuntary movement of respiratory muscles and lower limb muscles after this drug had been given for four months. This involuntary movement appeared spontaneously at resting state and disappeared during sleep. Surface EMG demonstrated a synchronous grouping discharge in m. orbicularis oris, m. sternocleidomastoideus and m. interstales which synchronized with diaphragmatic movement on cinefluorography. Involuntary movement of the lower limbs was synchronous bilaterally and had little relationship with diaphragmatic movement. This involuntary movement was irregular not only in rhythm but also in duration. According to this irregular nature, we diagnosed this involuntary movement as respiratory dyskinesia with limb dyskinesia that belongs to tardive dyskinesia. After cessation of clebopride malate limb dyskinesia disappeared rapidly and respiratory dyskinesia markedly decreased. We emphasize that respiratory dyskinesia should be differentiated from psychogenic hyperventilation as easily misdiagnosed on initial examination.

Thyroid storm complicated by bicytopenia and disseminated intravascular coagulation.

PubMed

Tokushima, Yoshinori; Sakanishi, Yuta; Nagae, Kou; Tokushima, Midori; Tago, Masaki; Tomonaga, Motosuke; Yoshioka, Tsuneaki; Hyakutake, Masaki; Sugioka, Takashi; Yamashita, Shu-ichi

2014-07-24

Male, 23. Thyroid storm. Delirium • diarrhea • fever • hypertension • hyperventilation • tachycardia • weight loss. -. -. Endocrinology and Metabolic. Unusual clinical course. The clinical presentation of thyroid storm includes fever, tachycardia, hypertension, and neurological abnormalities. It is a serious condition with a high mortality rate. Furthermore, some other complications affect the clinical course of thyroid storm. Although it is reported that prognosis is poor when thyroid storm is complicated by disseminated intravascular coagulation syndrome (DIC) and leukopenia, reports of such cases are rare. A 23-year-old man presented with delirium, high pyrexia, diarrhea, and weight loss of 18 kg over 2 months. According to the criteria of Burch and Wartofsky, he was diagnosed with thyroid storm on the basis of his symptom-complex and laboratory data that confirmed the presence of hyperthyroidism. Investigations also found leukopenia, thrombocytopenia, and disseminated intravascular coagulation, all of which are very rare complications of thyroid storm. We successfully treated him with combined therapy including anti-thyroid medication, despite leukopenia. Early diagnosis and treatment are essential in ensuring a good outcome for patients with this rare combination of medical problems.

Inhomogeneity of pulmonary perfusion during sustained microgravity on SLS-1

NASA Technical Reports Server (NTRS)

Prisk, G. Kim; Guy, Harold J. B.; Elliott, Ann R.; West, John B.

1994-01-01

We studied the effects of gravity on the inhomogeneity of pulmonary perfusion in humans by performing hyperventilation-breath-hold single-breath measurements before, during, and after 9 days of continuous exposure to microgravity during the Spacelab Life Sciences-1 (SLS-1) mission. In microgravity the indicators of inhomogeneity of perfusion, especially the size of cardiogenic oscillations in expired CO2 and the height of phase IV, were markedly reduced. Cardiogenic oscillations were reduced to approximately 60% of their preflight standing size, and the height of phase IV was between 0 and -8% (a terminal fall became a small terminal rise) of the preflight standing value. The terminal change in expired CO2 was nearly abolished in microgravity, indicating more uniformity of blood flow between lung units that close and those that remain open at the end of expiration. A possible explanation of this observation is the disappearance of gravity-dependent topographic inequality of blood flow. The residual cardiogenic oscillations in expired CO2 imply a persisting inhomogeneity of perfusion in the absence of gravity, probably in lung regions that are not within the same acinus.

Piston-pump-type high frequency oscillatory ventilation for neonates with congenital diaphragmatic hernia: a new protocol.

PubMed

Tamura, M; Tsuchida, Y; Kawano, T; Honna, T; Ishibashi, R; Iwanaka, T; Morita, Y; Hashimoto, H; Tada, H; Miyasaka, K

1988-05-01

High frequency ventilation and extracorporeal membrane oxygenation (ECMO) are devices that are expected to save the lives of newborn infants whose pulmonary conditions have deteriorated. A piston-pump-type high-frequency oscillator (HFO), developed by Bryan and Miyasaka called "Hummingbird," is considered to be superior to high frequency "jet" ventilators or those of the flow-interrupter type, and was used successfully in two neonates with congenital diaphragmatic hernia (CDH) in a high-risk group. The first baby was on a conventional ventilator with pharmacologic support for the first 54 hours and then operated on. Postoperative deterioration necessitated the use of HFO for the next eight days. The infant then recovered uneventfully. For the second baby, HFO was necessary both preoperatively and postoperatively. This baby had a major diaphragmatic defect and her case was complicated with pneumothorax. There was a long stormy course on HFO (total, 70 days), but the patient was successfully extubated on the 75th day postoperatively and is now doing well. We believe active long preoperative stabilization with pharmacologic support and preoperative and postoperative hyperventilation with a piston-pump-type HFO may be a new innovative strategy for the management of severe CDH patients.

Interoceptive exposure exercises for social anxiety.

PubMed

Dixon, Laura J; Kemp, Joshua J; Farrell, Nicholas R; Blakey, Shannon M; Deacon, Brett J

2015-06-01

Individuals with social anxiety disorder (SAD) commonly experience panic attacks and evidence increased anxiety sensitivity (AS) specific to noticeable anxiety sensations. Interoceptive exposure (IE) is an effective treatment for reducing AS, but few IE tasks target fears of blushing, sweating, or trembling, which are incorporated within AS social concerns and especially feared by individuals with SAD. The primary study aims were trifold: (1) identify novel IE tasks that produce blushing, sweating, and/or trembling; (2) assess the intensity of sensations and anxiety produced by a series of novel and validated IE tasks; and (3) evaluate the incremental validity of combining an IE task and a speech task. Individuals (N = 55) with heightened fear of noticeably blushing, sweating, and/or trembling completed a control task and 8 IE tasks (e.g., hot sauce, hyperventilation). All tasks produced greater intensity of anxiety and sensations compared to the control task (ps < .001; range of η(p)(2) = .20-.50). Responses to the combination of an IE task and social task compared to a social task alone did not differ significantly. Future directions for research and clinical implications of the findings are discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sudden Failure of Swimming in Cold Water

PubMed Central

Keatinge, W. R.; Prys-Roberts, C.; Cooper, K. E.; Honour, A. J.; Haight, J.

1969-01-01

To investigate the effect of cold water on swimming four men who declared themselves good swimmers were immersed fully clothed on separate days in water at 23·7° and 4·7° C. The time that they were able to swim in the cold water was much shorter than in the warm. The two shortest swims ended after 1·5 and 7·6 minutes, before rectal temperature fell, when the men suddenly floundered after developing respiratory distress with breathing rates of 56–60/min. The other cold swims, by the two fattest men, ended less abruptly with signs of general and peripheral hypothermia. It is concluded that swimming in cold water was stopped partly by respiratory reflexes in the thin men and hypothermia in the fat, and partly by the cold water's high viscosity. The longer swimming times of the fat men are attributed largely to their greater buoyancy enabling them to keep their heads above water during the early hyperventilation. The findings explain some reports of sudden death in cold water. It is clearly highly dangerous to attempt to swim short distances to shore without a life-jacket in water near 0° C. PMID:5764250

A proposal to evaluate mechanistic efficacy of hallucinogens in addiction treatment.

PubMed

Burdick, Brittany Vasae; Adinoff, Bryon

2013-09-01

Current treatments for addiction are frequently ineffective. Hallucinogenic therapy has been indicated as helpful for a range of substance use disorders, yet this approach remains understudied and publicly unavailable. It is nonetheless a promising treatment, which has significant, long-term beneficial effects with single doses and a profile characterized by general safety, low toxicity, and non-addictiveness. However, pharmacological interventions, such as hallucinogens, should not be offered if the same effects (e.g. psychological insights/mystical experiences) and outcomes (e.g. decreased drug use) could be achieved absent pharmacological intervention. To date, there have been no clinical comparisons of drug-induced altered states with non-drug-induced states for addiction treatment. We propose and then outline a clinical trial to address this gap in knowledge. The proposed design would evaluate abstinence outcomes in a population of prescription opioid abusers after exposure to one of three conditions: a drug-induced altered state using psilocybin, a non-drug-induced altered state via hyperventilation (Holotropic Breathwork), and an active placebo with niacin. The outcomes of such a study would reveal important differences in therapeutic potential by discriminating hallucinogen-dependent effects from those psychological effects resulting from altered states.

Provisional report on diving-related fatalities in Australian waters 2008.

PubMed

Lippmann, John; Walker, Douglas; Lawrence, Chris; Fock, Andrew; Wodak, Thomas; Harris, Richard; Jamieson, Scott

2013-03-01

An individual case review of diving-related deaths, reported as occurring in Australia in 2008, was conducted as part of the DAN Asia-Pacific dive fatality reporting project. The case studies were compiled using reports from witnesses, the police and coroners. In each case, the particular circumstances of the accident and details from the post-mortem examination, where available, are provided. In total, there were 19 reported fatalities (the same as for 2007), 17 involving males. Twelve deaths occurred while snorkelling and/or breath-hold diving,and six while scuba diving. One diver died while using surface-supply breathing apparatus. Two breath-hold divers appear to have died as a result of apnoeic hypoxia, at least one case likely associated with hyperventilation. Two deaths resulted from trauma: one from impact with a boat and the other from an encounter with a great white shark. Cardiac-related issues were thought to have contributed to the deaths of five snorkellers and at least two, possibly three, scuba divers. Trauma from a marine creature, snorkelling or diving alone, apnoeic hypoxia and pre-existing medical conditions were once again features in several deaths in this series.

Alternative approaches to treatment of Central Sleep Apnea.

PubMed

Thomas, Robert Joseph

2014-03-01

Divergent approaches to treatment of hypocapnic central sleep apnea syndromes reflect the difficulties in taming a hyperactive respiratory chemoreflex. As both sleep fragmentation and a narrow CO 2 reserve or increased loop gain drive the disease, sedatives (to induce longer periods of stable non-rapid eye movement (NREM) sleep and reduce the destabilizing effects of arousals in NREM sleep) and CO 2 -based stabilization approaches are logical. Adaptive ventilation reduces mean hyperventilation yet can induce ventilator-patient dyssynchrony, while enhanced expiratory rebreathing space (EERS, dead space during positive pressure therapy) and CO 2 manipulation directly stabilize respiratory control by moving CO 2 above the apnea threshold. Carbonic anhydrase inhibition can provide further adjunctive benefits. Provent and Winx may be less likely to trigger central apneas or periodic breathing in those with a narrow CO 2 reserve. An oral appliance can meaningfully reduce positive pressure requirements and thus enable treatment of complex apnea. Novel pharmacological approaches may target mediators of carotid body glomus cell excitation, such as the balance between gas neurotransmitters. In complex apnea patients, single mode therapy is not always successful, and multi-modality therapy might need to be considered. Phenotyping of sleep apnea beyond conventional scoring approaches is the key to optimal management.

Hypnosis in pediatrics: applications at a pediatric pulmonary center.

PubMed

Anbar, Ran D

2002-12-03

This report describes the utility of hypnosis for patients who presented to a Pediatric Pulmonary Center over a 30 month period. Hypnotherapy was offered to 303 patients from May 1, 1998 - October 31, 2000. Patients offered hypnotherapy included those thought to have pulmonary symptoms due to psychological issues, discomfort due to medications, or fear of procedures. Improvement in symptoms following hypnosis was observed by the pulmonologist for most patients with habit cough and conversion reaction. Improvement of other conditions for which hypnosis was used was gauged based on patients' subjective evaluations. Hypnotherapy was associated with improvement in 80% of patients with persistent asthma, chest pain/pressure, habit cough, hyperventilation, shortness of breath, sighing, and vocal cord dysfunction. When improvement was reported, in some cases symptoms resolved immediately after hypnotherapy was first employed. For the others improvement was achieved after hypnosis was used for a few weeks. No patients' symptoms worsened and no new symptoms emerged following hypnotherapy. Patients described in this report were unlikely to have achieved rapid improvement in their symptoms without the use of hypnotherapy. Therefore, hypnotherapy can be an important complementary therapy for patients in a pediatric practice.

[Variations of respiratory parameters in healthy men].

PubMed

Shishkin, G S; Ustiuzhaninova, N V

2006-01-01

The subjects of the study were 656 healthy men living in the south of West Siberia, in whom the basic parameters of gas exchange, lung ventilation, static lung volumes, and bronchial permeability were measured. The significance and incidence of non-pathological changes in the system of external respiration were defined on the basis of statistical and cluster analysis of these parameters. The study shows that individuals with functional changes can be divided into four groups with different characteristics: 1. Steady mobilization of the reserve tissue of the respiratory parts of the lungs as a physiological defense reaction to unfavorable ecological factors; 2. An increased airiness of the respiratory tissue as a sign of a compensatory reaction directed towards maintaining gas homeostasis in frequent and prominent overload of the system of external respiration; 3. Steady hyperventilation as a direct functional response of the organism to the slowing down of oxygen mass transfer in the respiratory parts of the lungs; 4. Restriction of external respiration due to respiratory diseases in the past. Despite differences in the origin, all the studied functional changes have one common feature, i.e. their association with a decrease in external respiratory reserve; all of them should be considered pulmonological risk manifestations.

Anxiety sensitivity and panic reactivity to bodily sensations: relation to quit-day (acute) nicotine withdrawal symptom severity among daily smokers making a self-guided quit attempt.

PubMed

Marshall, Erin C; Johnson, Kirsten; Bergman, Jenna; Gibson, Laura E; Zvolensky, Michael J

2009-10-01

The current investigation explored the main and interactive effects of panic attacks in response to laboratory-induced bodily sensations and anxiety sensitivity in predicting acute nicotine withdrawal symptoms among daily smokers making a self-guided quit attempt. Participants were 99 daily smokers (58% women; M(age) = 28.4 years, SD = 11.7) who completed a battery of questionnaires, a voluntary hyperventilation challenge, and a measure of nicotine withdrawal symptoms 12 hr after making a self-guided quit attempt. Results indicated that the interaction of anxiety sensitivity and panic responsivity to the challenge predicted quit-day nicotine withdrawal symptom severity above and beyond the main effects (p < .05). The form of the interaction indicated that the relationship between postchallenge panic attack status and acute nicotine withdrawal was more robust among individuals who were low in anxiety sensitivity. Individuals who did not experience a panic attack posthyperventilation who were also low in anxiety sensitivity reported the lowest levels of nicotine withdrawal. Results suggest that anxiety sensitivity may be less relevant with regard to acute nicotine withdrawal severity among individuals with panic-related problems.

[Sport and atopy].

PubMed

Didier, A; Mazieres, J; Kouevijin, G; Tetu, L; Rivière, D

2003-11-01

The atopic diseases, asthma, allergic rhinitis and atopic dermatitis, are common in children, adolescents and young adults. They may have important consequences on physical exercise, especially asthma. Elite athletes have been observed to have a high prevalence of asthma (and perhaps also rhinitis). The reasons for this observation are still debated, but different mechanisms linked to the intensity of physical activity in athletes are probably involved. Exercise-induced symptoms should be confirmed not only from the clinical history but also by objective measurements of lung function. In elite athletes confirmation of exercise-induced asthma might be difficult and may require special diagnostic tests such as bronchial provocation by eucapnic voluntary hyperventilation. Several drugs are effective in exercise-induced prevention of nasal and bronchial symptoms. Therapeutic approaches for atopic diseases in international guidelines (GINA and ARIA) are generally compatible with anti-doping laws but require compliance with specific prescription rules. A better understanding of mechanisms and risk factors involved in the increase of asthma prevalence in elite athletes may permit prevention by modifying training conditions during exercise. Atopic diseases are common in athletes. They require special therapeutic considerations. The increasing prevalence of respiratory asthma-like symptoms in elite athlete is opening new paths for research into airway physiology in extreme conditions.

Oxygen control of breathing by an olfactory receptor activated by lactate

PubMed Central

Chang, Andy J.; Ortega, Fabian E.; Riegler, Johannes; Madison, Daniel V.; Krasnow, Mark A.

2015-01-01

Summary Animals have evolved homeostatic responses to changes in oxygen availability that act on different time scales. Although the hypoxia-inducible factor (HIF) transcriptional pathway that controls long term responses to low oxygen (hypoxia) has been established1, the pathway that mediates acute responses to hypoxia in mammals is not well understood. Here we show that the olfactory receptor Olfr78 is highly and selectively expressed in oxygen-sensitive glomus cells of the carotid body, a chemosensory organ at the carotid artery bifurcation that monitors blood oxygen and stimulates breathing within seconds when oxygen declines2. Olfr78 mutants fail to increase ventilation in hypoxia but respond normally to hypercapnia. Glomus cells are present in normal numbers and appear structurally intact, but hypoxia-induced carotid body activity is diminished. Lactate, a metabolite that rapidly accumulates in hypoxia and induces hyperventilation3–6, activates Olfr78 in heterologous expression experiments, induces calcium transients in glomus cells, and stimulates carotid sinus nerve activity through Olfr78. We propose that in addition to its role in olfaction, Olfr78 acts as a hypoxia sensor in the breathing circuit by sensing lactate produced when oxygen levels decline. PMID:26560302

Lungs in Heart Failure

PubMed Central

Apostolo, Anna; Giusti, Giuliano; Gargiulo, Paola; Bussotti, Maurizio; Agostoni, Piergiuseppe

2012-01-01

Lung function abnormalities both at rest and during exercise are frequently observed in patients with chronic heart failure, also in the absence of respiratory disease. Alterations of respiratory mechanics and of gas exchange capacity are strictly related to heart failure. Severe heart failure patients often show a restrictive respiratory pattern, secondary to heart enlargement and increased lung fluids, and impairment of alveolar-capillary gas diffusion, mainly due to an increased resistance to molecular diffusion across the alveolar capillary membrane. Reduced gas diffusion contributes to exercise intolerance and to a worse prognosis. Cardiopulmonary exercise test is considered the “gold standard” when studying the cardiovascular, pulmonary, and metabolic adaptations to exercise in cardiac patients. During exercise, hyperventilation and consequent reduction of ventilation efficiency are often observed in heart failure patients, resulting in an increased slope of ventilation/carbon dioxide (VE/VCO2) relationship. Ventilatory efficiency is as strong prognostic and an important stratification marker. This paper describes the pulmonary abnormalities at rest and during exercise in the patients with heart failure, highlighting the principal diagnostic tools for evaluation of lungs function, the possible pharmacological interventions, and the parameters that could be useful in prognostic assessment of heart failure patients. PMID:23365739

Hypnosis in pediatrics: applications at a pediatric pulmonary center

PubMed Central

Anbar, Ran D

2002-01-01

Background This report describes the utility of hypnosis for patients who presented to a Pediatric Pulmonary Center over a 30 month period. Methods Hypnotherapy was offered to 303 patients from May 1, 1998 – October 31, 2000. Patients offered hypnotherapy included those thought to have pulmonary symptoms due to psychological issues, discomfort due to medications, or fear of procedures. Improvement in symptoms following hypnosis was observed by the pulmonologist for most patients with habit cough and conversion reaction. Improvement of other conditions for which hypnosis was used was gauged based on patients' subjective evaluations. Results Hypnotherapy was associated with improvement in 80% of patients with persistent asthma, chest pain/pressure, habit cough, hyperventilation, shortness of breath, sighing, and vocal cord dysfunction. When improvement was reported, in some cases symptoms resolved immediately after hypnotherapy was first employed. For the others improvement was achieved after hypnosis was used for a few weeks. No patients' symptoms worsened and no new symptoms emerged following hypnotherapy. Conclusions Patients described in this report were unlikely to have achieved rapid improvement in their symptoms without the use of hypnotherapy. Therefore, hypnotherapy can be an important complementary therapy for patients in a pediatric practice. PMID:12460456

Chronic hypobaric hypoxia increases isolated rat fast-twitch and slow-twitch limb muscle force and fatigue.

PubMed

El-Khoury, R; Bradford, A; O'Halloran, K D

2012-01-01

Chronic hypoxia alters respiratory muscle force and fatigue, effects that could be attributed to hypoxia and/or increased activation due to hyperventilation. We hypothesized that chronic hypoxia is associated with phenotypic change in non-respiratory muscles and therefore we tested the hypothesis that chronic hypobaric hypoxia increases limb muscle force and fatigue. Adult male Wistar rats were exposed to normoxia or hypobaric hypoxia (PB=450 mm Hg) for 6 weeks. At the end of the treatment period, soleus (SOL) and extensor digitorum longus (EDL) muscles were removed under pentobarbitone anaesthesia and strips were mounted for isometric force determination in Krebs solution in standard water-jacketed organ baths at 25 °C. Isometric twitch and tetanic force, contractile kinetics, force-frequency relationship and fatigue characteristics were determined in response to electrical field stimulation. Chronic hypoxia increased specific force in SOL and EDL compared to age-matched normoxic controls. Furthermore, chronic hypoxia decreased endurance in both limb muscles. We conclude that hypoxia elicits functional plasticity in limb muscles perhaps due to oxidative stress. Our results may have implications for respiratory disorders that are characterized by prolonged hypoxia such as chronic obstructive pulmonary disease (COPD).

Simultaneous diffuse near-infrared imaging of hemodynamic and oxygenation changes and electroencephalographic measurements of neuronal activity in the human brain

NASA Astrophysics Data System (ADS)

Noponen, Tommi; Kicic, Dubravko; Kotilahti, Kalle; Kajava, Timo; Kahkonen, Seppo; Nissila, Ilkka; Merilainen, Pekka; Katila, Toivo

2005-04-01

Visually evoked hemodynamic responses and potentials were simultaneously measured using a 16-channel optical imaging instrument and a 60-channel electroencephalography instrument during normo-, hypo- and hypercapnia from three subjects. Flashing and pattern-reversed checkerboard stimuli were used. The study protocol included two counterbalanced measurements during both normo- and hypocapnia and normo- and hypercapnia. Hypocapnia was produced by controlled hyperventilation and hypercapnia by breathing carbon dioxide enriched air. Near-infrared imaging was also used to monitor the concentration changes of oxy- and deoxyhaemoglobin due to hypo- and hypercapnia. Hemodynamic responses and evoked potentials were successfully detected for each subject above the visual cortex. The latencies of the hemodynamic responses during hypocapnia were shorter whereas during hypercapnia they were longer when compared to the latencies during normocapnia. Hypocapnia tended to decrease the latencies of visually evoked potentials compared to those during normocapnia while hypercapnia did not show any consistent effect to the potentials. The developed measurement setup and the study protocol provide the opportunity to investigate the neurovascular coupling and the links between the baseline level of blood flow, electrical activity and hemodynamic responses in the human brain.

Oxygen regimen in the human peripheral tissue during space flights

NASA Astrophysics Data System (ADS)

Haase, H.; Kovalenko, E. A.; Vacek, A.; Bobrovnickij, M. P.; Jarsumbeck, B.; Semencov, V. N.; Sarol, Z.; Hideg, J.; Zlatarev, K.

A survey of the results of the experiment "Oxygen," carried out within the scope of the INTERKOSMOS program in members of the permanent crews and of international visiting expeditions to the Soviet orbital station Salyut-6, is given. During the 7-day space flights of the international visiting expeditions a significant decrease in pO 2 ic by 3.28 kPa was observed. Local oxygen utilization reduced significantly by 0.44 kPa. During hyperventilation testing after return to earth a statistically significant decrease in the peak value by 1.39 kPa was noted. In the long-term crews of the orbital station Salyut-6 the highest decrease in pO 2 ic of 3.8 kPa and the absolutely lowest value of 3.4 ± 0.5 kPa during space flight were observed. The decrease in local oxygen utilization during the flight of 0.8 kPa/min was greater than that of the visiting crews. The results indicate the importance of investigating the dynamics of the oxygen regimen for medical control of the crew members both during the space flight and during the readaptation phase after return to earth.

Mutation spectrum of Joubert syndrome and related disorders among Arabs

PubMed Central

Ben-Salem, Salma; Al-Shamsi, Aisha M; Gleeson, Joseph G; Ali, Bassam R; Al-Gazali, Lihadh

2014-01-01

Joubert syndrome (JS) is a rare autosomal recessive (AR), neurological condition characterized by dysgenesis of the cerebellar vermis with the radiological hallmark of molar tooth sign, oculomotor apraxia, recurrent hyperventilation and intellectual disability. Most cases display a broad spectrum of additional features, including polydactyly, retinal dystrophy and renal abnormalities, which define different subtypes of JS-related disorders (JSRDs). To date, 23 genes have been shown to cause JSRDs, and although most of the identified genes encode proteins involved in cilia function or assembly, the molecular mechanisms associated with ciliary signaling remain enigmatic. Arab populations are ethnically diverse with high levels of consanguinity (20–60%) and a high prevalence of AR disorders. In addition, isolated communities with very-high levels of inbreeding and founder mutations are common. In this article, we review the 70 families reported thus far with JS and JSRDs that have been studied at the molecular level from all the Arabic countries and compile the mutations found. We show that JS and the related JSRDs are genetically heterogeneous in Arabs, with 53 mutations in 15 genes. Thirteen of these mutations are potentially founder mutations for the region. PMID:27081510

Hypocapnic hypothesis of Leigh disease.

PubMed

Pronicka, Ewa

2017-04-01

Leigh syndrome (LS) is a neurogenetic disorder of children caused by mutations in at least 75 genes which impair mitochondrial bioenergetics. The changes have typical localization in basal ganglia and brainstem, and typical histological picture of spongiform appearance, vascular proliferation and gliosis. ATP deprivation, free radicals and lactate accumulation are suspected to be the causes. Hypocapnic hypothesis proposed in the paper questions the energy deprivation as the mechanism of LS. We assume that the primary harmful factor is hypocapnia (decrease in pCO 2 ) and respiratory alkalosis (increase in pH) due to hyperventilation, permanent or in response to stress. Inside mitochondria, the pH signal of high pH/low bicarbonate ion (HCO - 3 ) is transmitted by soluble adenyl cyclase (sAC) through cAMP dependent manner. The process can initiate brain lesions (necrosis, apoptosis, hypervascularity) in OXPHOS deficient cells residing at the LS area of the brain. The major message of the article is that it is not the ATP depletion but intracellular alkalization (and/or hyperoxia?) which seem to be the cause of LS. The paper includes suggestions concerning the methodology for further research on the LS mechanism and for therapeutic strategy. Copyright © 2017 The Author. Published by Elsevier Ltd.. All rights reserved.

Respiratory responses to intermittent hypoxia in unsedated piglets: relation to substance P binding in brainstem.

PubMed

Laferrière, André; Moss, Immanuela Ravé

2004-10-12

Respiratory responses to single intermittent hypoxia (5 min 21% O(2), 5 min 8% O(2) X6) in 5-6, 10-11, 21-22 and 26-27 day-old piglets, and to recurrent six daily intermittent hypoxia in 10-11 and 26-27 day-old piglets were assessed. Substance P binding in the piglets' brainstem immediately after the last hypoxic episode was measured. All piglets hyperventilated during hypoxia. Weight adjusted inspired ventilation, tidal volume and instantaneous flow decreased with age. The oldest piglets uniquely displayed attenuated ventilation and tidal volume during the sixth versus first hypoxic episode with single intermittent hypoxia, and reduced inspired ventilation and tidal volume during the first hypoxic episode on the sixth daily hypoxia compared to single hypoxia. By contrast, substance P binding was greatly reduced in the solitary, hypoglossal, paraambigual and lateral reticular brainstem nuclei of both younger and older piglets following either single or recurrent intermittent hypoxia. Thus, the reduction in membrane-bound neurokinin receptors by intermittent hypoxia, presumably consequent to endogenously released substance P, does not exclusively determine whether the ventilatory response to that hypoxia will be attenuated or not.

[Real-time feedback systems for improvement of resuscitation quality].

PubMed

Lukas, R P; Van Aken, H; Engel, P; Bohn, A

2011-07-01

The quality of chest compression is a determinant of survival after cardiac arrest. Therefore, the European Resuscitation Council (ERC) 2010 guidelines on resuscitation strongly focus on compression quality. Despite its impact on survival, observational studies have shown that chest compression quality is not reached by professional rescue teams. Real-time feedback devices for resuscitation are able to measure chest compression during an ongoing resuscitation attempt through a sternal sensor equipped with a motion and pressure detection system. In addition to the electrocardiograph (ECG) ventilation can be detected by transthoracic impedance monitoring. In cases of quality deviation, such as shallow chest compression depth or hyperventilation, feedback systems produce visual or acoustic alarms. Rescuers can thereby be supported and guided to the requested quality in chest compression and ventilation. Feedback technology is currently available both as a so-called stand-alone device and as an integrated feature in a monitor/defibrillator unit. Multiple studies have demonstrated sustainable enhancement in the education of resuscitation due to the use of real-time feedback technology. There is evidence that real-time feedback for resuscitation combined with training and debriefing strategies can improve both resuscitation quality and patient survival. Chest compression quality is an independent predictor for survival in resuscitation and should therefore be measured and documented in further clinical multicenter trials.

Inhibiting the Physiological Stress Effects of a Sustained Attention Task on Shoulder Muscle Activity.

PubMed

Wixted, Fiona; O'Riordan, Cliona; O'Sullivan, Leonard

2018-01-11

The objective of this study was to investigate if a breathing technique could counteract the effects of hyperventilation due to a sustained attention task on shoulder muscle activity. The trend towards higher levels of automation in industry is increasing. Consequently, manufacturing operators often monitor automated process for long periods of their work shift. Prolonged monitoring work requires sustained attention, which is a cognitive process that humans are typically poor at and find stressful. As sustained attention becomes an increasing requirement of manufacturing operators' job content, the resulting stress experienced could contribute to the onset of many health problems, including work related musculoskeletal disorders (WRMSDs). The SART attention test was completed by a group of participants before and after a breathing intervention exercise. The effects of the abdominal breathing intervention on breathing rate, upper trapezius muscle activity and end-tidal CO₂ were evaluated. The breathing intervention reduced the moderation effect of end-tidal CO₂ on upper trapezius muscle activity. Abdominal breathing could be a useful technique in reducing the effects of sustained attention work on muscular activity. This research can be applied to highly-automated manufacturing industries, where prolonged monitoring of work is widespread and could, in its role as a stressor, be a potential contributor to WRMSDs.

Toxicosis associated with ingestion of quick-dissolve granulated chlorine in a dog.

PubMed

Hofmeister, Aaron S; Heseltine, Johanna C; Sharp, Claire R

2006-10-15

A dog was referred for treatment after ingestion of quick-dissolve chlorine granules intended for use in a swimming pool. At evaluation 18 hours after ingestion of the granules, the dog had tachypnea, signs of depression, approximately 5% dehydration, oral mucositis, and a productive cough. Increased respiratory tract sounds and wheezes were ausculted in all lung fields. Complete blood count revealed erythrocytosis and lymphopenia. Serum biochemical analyses revealed mildly high activities of hepatic enzymes and creatine kinase. Arterial blood gas concentrations were consistent with hypoxemia and hyperventilation. Thoracic radiography revealed widespread pulmonary alveolar infiltrates predominantly affecting the ventral portions of both lungs, consistent with noncardiogenic pulmonary edema secondary to aspiration of the granulated chlorine. Initial treatment included IV administration of an electrolyte solution with supplemental KCl, ranitidine, furosemide, cefotaxime, buprenorphine, and supplemental oxygen. Subsequent treatment included administration of meloxicam and an endoscopically placed percutaneous gastrostomy tube. Endoscopic examination revealed esophagitis and mild gastritis; therefore, metoclopramide and sucralfate were also administered. Fifteen days later, the gastrostomy tube was removed prior to discharge; endoscopic examination revealed grossly normal esophageal and gastric mucosa, and thoracic radiography revealed complete resolution of the lung lesions. Although ingestion of granulated chlorine is rare in veterinary patients, the resulting disease processes are common and can be treated successfully.

Successful outcome after intravenous gasoline injection.

PubMed

Domej, Wolfgang; Mitterhammer, Heike; Stauber, Rudolf; Kaufmann, Peter; Smolle, Karl Heinz

2007-12-01

Gasoline, ingested intentionally or accidentally, is toxic. The majority of reported cases of gasoline intoxication involve oral ingestion or inhalation. Data are scarce on complications and outcomes following hydrocarbon poisoning by intravenous injection. Following a suicide attempt by intravenous self-injection of 10 ml of gasoline, a 26-year-old medical student was admitted to the intensive care unit (ICU) with hemoptysis, symptoms of acute respiratory failure, chest pain, and severe abdominal cramps. Gas exchange was severely impaired and a chest x-ray indicated chemical pneumonitis. Initial treatment consisted of mechanical ventilation, supportive hyperventilation, administration of nitrogen oxide (NO), and prednisone. Unfortunately, the patient developed multi-organ dysfunction syndrome (MODS) complicated by life-threatening severe vasoplegia within 24 hours after gasoline injection. High doses of vasopressors along with massive amounts of parenteral fluids were necessary. Despite fluid replacement, renal function worsened and required hemofiltration on 5 sequential days. After 12 days of intensive care management, the patient recovered completely and was discharged to a psychiatric care facility. Intravenous gasoline injection causes major injury to the lungs, the organ bearing the first capillary bed encountered. Treatment of gasoline poisoning is symptomatic because no specific antidote is available. Early and aggressive supportive care may be conducive to a favorable outcome with minimal residual pulmonary sequelae.

The brain acid-base homeostasis and serotonin: A perspective on the use of carbon dioxide as human and rodent experimental model of panic.

PubMed

Leibold, N K; van den Hove, D L A; Esquivel, G; De Cort, K; Goossens, L; Strackx, E; Buchanan, G F; Steinbusch, H W M; Lesch, K P; Schruers, K R J

2015-06-01

Panic attacks (PAs), the core feature of panic disorder, represent a common phenomenon in the general adult population and are associated with a considerable decrease in quality of life and high health care costs. To date, the underlying pathophysiology of PAs is not well understood. A unique feature of PAs is that they represent a rare example of a psychopathological phenomenon that can be reliably modeled in the laboratory in panic disorder patients and healthy volunteers. The most effective techniques to experimentally trigger PAs are those that acutely disturb the acid-base homeostasis in the brain: inhalation of carbon dioxide (CO2), hyperventilation, and lactate infusion. This review particularly focuses on the use of CO2 inhalation in humans and rodents as an experimental model of panic. Besides highlighting the different methodological approaches, the cardio-respiratory and the endocrine responses to CO2 inhalation are summarized. In addition, the relationships between CO2 level, changes in brain pH, the serotonergic system, and adaptive physiological and behavioral responses to CO2 exposure are presented. We aim to present an integrated psychological and neurobiological perspective. Remaining gaps in the literature and future perspectives are discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Experimental studies on brain hematoma detection and oxygenation monitoring using PRM/NIR sensors

NASA Astrophysics Data System (ADS)

Zheng, Liu; Lee, Hyo Sang; Wilson, David A.; Hanley, Daniel F.; Lokos, Sandor; Kim, Jin

1997-08-01

Real time noninvasive head injury detection is needed in critical care facilities and triage site with limited resources. One tool missing right now is a small and fast noninvasive sensor which can help urgent care workers to (1) diagnose the location and severity of the injury, (2) to perform on site pre-hospital treatment if necessary, and (3) to make a decision on what kind of further medical action is needed. On the other hand, continuous monitoring of cerebral blood oxygenation is also needed in intensive care unit and in operation rooms. Pseudo-random modulation/near infrared sensor (PRM/NIR sensor) is developed to address these issues. It relies on advanced techniques in diode laser cw modulation and time resolved spectroscopy to perform fast and noninvasive brain tissue diagnostics. Phantom experiments have been conducted to study the feasibility of the sensor. Brain's optical properties are simulated with solutions of intralipid and ink. Hematomas are simulated with bags of paint and hemoglobin immersed in the solution of varies sizes, depths, and orientations. Effects of human skull and hair are studied experimentally. In animal experiment, the sensor was used to monitor the cerebral oxygenation change due to hypercapnia, hypoxia, and hyperventilation. Good correlations were found between NIR measurement parameters and physiological changes induced to the animals.

Reactive oxygen metabolites (ROMs) as an index of oxidative stress in obstructive sleep apnea patients.

PubMed

Christou, Kostas; Markoulis, Nikolaos; Moulas, Anargyros N; Pastaka, Chaido; Gourgoulianis, Kostantinos I

2003-09-01

Obstructive sleep apnea syndrome (OSA) is accompanied by oxygen desaturation and arousal from sleep. Free oxygen radicals are highly reactive molecules which could be produced by the OSA phenomenon of hypoxia/reoxygenation: cyclical alterations of arterial oxygen saturation with oxygen desaturation developing in response to apneas followed by resumption of oxygen saturation during hyperventilation. On the basis of these considerations, it was hypothesized that OSA may be linked to increased oxidative stress. Twenty-six participants gave an interview during which a physician asked them about their age, smoking habits, and symptoms such as excessive daytime sleepiness and snoring. Physical examination and polysomnography were performed during their hospitalization. Reactive oxygen metabolites (ROMs) were measured in blood samples by the diacron reactive oxygen metabolites (D-ROM) test. Twenty-one out of 26 subjects had an apnea/hypopnea index greater than 5 (OSA group). The measurement of free radicals was high in OSA patients. Furthermore, ROMs values in OSA patients were linearly correlated with the apnea/hypopnea index (R = 0.426; p = 0.042). The predictive value of a positive D-ROM test is 81%. ROMs were elevated in patients with OSA. When OSA was severe, similarly the value of ROMs in blood samples was enhanced, and the probable underlying mechanism for these events is the hypoxia/reoxygenation phenomenon.

Cardiorespiratory interactions and blood flow generation during cardiac arrest and other states of low blood flow.

PubMed

Sigurdsson, Gardar; Yannopoulos, Demetris; McKnite, Scott H; Lurie, Keith G

2003-06-01

Recent advances in cardiopulmonary resuscitation have shed light on the importance of cardiorespiratory interactions during shock and cardiac arrest. This review focuses on recently published studies that evaluate factors that determine preload during chest compression, methods that can augment preload, and the detrimental effects of hyperventilation and interrupting chest compressions. Refilling of the ventricles, so-called ventricular preload, is diminished during cardiovascular collapse and resuscitation from cardiac arrest. In light of the potential detrimental effects and challenges of large-volume fluid resuscitations, other methods have increasing importance. During cardiac arrest, active decompression of the chest and impedance of inspiratory airflow during the recoil of the chest work by increasing negative intrathoracic pressure and, hence, increase refilling of the ventricles and increase cardiac preload, with improvement in survival. Conversely, increased frequency of ventilation has detrimental effects on coronary perfusion pressure and survival rates in cardiac arrest and severe shock. Prolonged interruption of chest compressions for delivering single-rescuer ventilation or analyzing rhythm before shock delivery is associated with decreased survival rate. Cardiorespiratory interactions are of profound importance in states of cardiovascular collapse in which increased negative intrathoracic pressure during decompression of the chest has a favorable effect and increased intrathoracic pressure with ventilation has a detrimental effect on survival rate.

Relation of insulin resistance to neurocognitive function and electroencephalography in obese children.

PubMed

Akın, Onur; Eker, İbrahim; Arslan, Mutluay; Yavuz, Süleyman Tolga; Akman, Sevil; Taşçılar, Mehmet Emre; Ünay, Bülent

2017-10-26

Childhood obesity may lead to neuronal impairment in both the peripheral and the central nervous system. This study aimed to investigate the impact of obesity and insulin resistance (IR) on the central nervous system and neurocognitive functions in children. Seventy-three obese children (38 male and 35 female) and 42 healthy children (21 male and 21 female) were recruited. Standard biochemical indices and IR were evaluated. The Wechsler Intelligence Scale for Children-Revised (WISC-R) and electroencephalography (EEG) were administered to all participants. The obese participants were divided into two groups based on the presence or absence of IR, and the data were compared between the subgroups. Only verbal scores on the WISC-R in the IR+ group were significantly lower than those of the control and IR- groups. There were no differences between the groups with respect to other parameters of the WISC-R or the EEG. Verbal scores of the WISC-R were negatively correlated with obesity duration and homeostatic model assessment-insulin resistance (HOMA-IR) values. EEGs showed significantly more frequent 'slowing during hyperventilation' (SDHs) in obese children than non-obese children. Neurocognitive functions, particularly verbal abilities, were impaired in obese children with IR. An early examination of cognitive functions may help identify and correct such abnormalities in obese children.

Refractory status epilepticus and autoimmune encephalitis with GABAAR and GAD65 antibodies: A case report.

PubMed

Gagnon, Maude-Marie; Savard, Martin; Mourabit Amari, Karim

2016-04-01

Autoimmune encephalitis is an inflammatory disorder of the brain that may be associated with different neuronal antibodies. Recently, an increasing number of valuable autoantibodies have been identified, including GABAAR antibodies, which appear to be associated with a severe form of encephalitis with refractory status epilepticus. We report here on a patient with encephalitis associated with GAD65 and GABAAR antibodies, an entity that remains an understudied topic, with an unanticipated clinical presentation and we describe the longitudinal follow-up. We report a case of encephalitis associated with GAD65 and GABAAR antibodies; we describe clinical and paraclinical features and the longitudinal follow-up. Our case presented with dysgueusia, dysosmia and episodes of hyperventilation that evolved into a refractory status epilepticus. Multiple anticonvulsant drugs were required. An aggressive immunotherapy was associated with a relative favorable outcome, in regard of epilepsy and cognitive functions. However, a relapse occurred and a full recovery was not observed at the last follow-up visit. There was no correlation between GAD65 antibodies titers and disease activity. Autoimmune encephalitis associated with GABAAR and GAD65 antibodies might be a severe and refractory disease. The appropriate treatment is currently unknown for those patients. Copyright © 2016 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

A dual mode breath sampler for the collection of the end-tidal and dead space fractions.

PubMed

Salvo, P; Ferrari, C; Persia, R; Ghimenti, S; Lomonaco, T; Bellagambi, F; Di Francesco, F

2015-06-01

This work presents a breath sampler prototype automatically collecting end-tidal (single and multiple breaths) or dead space air fractions (multiple breaths). This result is achieved by real time measurements of the CO2 partial pressure and airflow during the expiratory and inspiratory phases. Suitable algorithms, used to control a solenoid valve, guarantee that a Nalophan(®) bag is filled with the selected breath fraction even if the subject under test hyperventilates. The breath sampler has low pressure drop (<0.5 kPa) and uses inert or disposable components to avoid bacteriological risk for the patients and contamination of the breath samples. A fully customisable software interface allows a real time control of the hardware and software status. The performances of the breath sampler were evaluated by comparing (a) the CO2 partial pressure calculated during the sampling with the CO2 pressure measured off-line within the Nalophan(®) bag; (b) the concentrations of four selected volatile organic compounds in dead space, end-tidal and mixed breath fractions. Results showed negligible deviations between calculated and off-line CO2 pressure values and the distributions of the selected compounds into dead space, end-tidal and mixed breath fractions were in agreement with their chemical-physical properties. Copyright © 2015. Published by Elsevier Ltd.

Influence of drive and timing mechanisms on breathing pattern and ventilation during mental task performance.

PubMed

Wientjes, C J; Grossman, P; Gaillard, A W

1998-09-01

Assessment of multiple respiratory measures may provide insight into how behavioral demands affect the breathing pattern. This is illustrated by data from a study among 44 subjects, in which tidal volume, respiration rate, minute ventilation and indices of central drive and timing mechanisms were assessed via inductive plethysmography, in addition to end-tidal PCO2. After a baseline, three conditions of a memory comparison task were presented. The first two conditions differed only with regard to the presence or absence of feedback of performance (NFB and FB). In the third 'all-or-nothing' (AON) condition, subjects only received a monetary bonus, if their performance exceeded that of the previous two conditions. Minute ventilation increased from baseline to all task conditions, and from NFB and FB to AON. Respiration rate increased in all task conditions, but there were no differences between task conditions. Tidal volume decreased during NFB, but was equal to baseline during FB and AON. Of the respiratory control indices, inspiratory flow rate covaried much more closely with minute ventilation than duty cycle. The task performance induced a minor degree of hyperventilation. The discussion focusses on how behavioral demands affect respiratory control processes to produce alterations in breathing pattern and ventilation.

An analogue assessment of repetitive hand behaviours in girls and young women with Rett syndrome.

PubMed

Wales, L; Charman, T; Mount, R H

2004-10-01

Rett syndrome is a neurodevelopmental disorder that almost exclusively affects females. In addition to neurodevelopmental regression and loss of hand skills, apraxia, deceleration of head growth, and increasing spasticity and scoliosis, a number of behavioural features are also seen, including stereotypic hand movements, hyperventilation and breath holding. The aim of the study was to investigate the extent to which analogue environmental conditions affected the frequency of repetitive hand behaviour in eight girls and young women with Rett syndrome. The frequency of repetitive hand movements was observed every 10 s for four 4-min sessions under the following conditions: Continuous Adult Attention, Adult Demands, Stimulation and No Stimulation. The frequency of repetitive hand movements was high -- they occurred in above 60% of all intervals in all conditions for all participants and at nearly 100% for some participants in some conditions. For one participant the frequency of repetitive hand movements was somewhat reduced in the Stimulation condition; for another it was relatively increased in the No Stimulation condition. Overall, environmental manipulations had relatively limited effects on repetitive hand behaviours. Repetitive hand behaviour in Rett syndrome may be maintained by automatic reinforcement or neurochemical processes and may not be primarily influenced by contingent reinforcement.

Do over 200 million healthy altitude residents really suffer from chronic Acid-base disorders?

PubMed

Zubieta-Calleja, Gustavo; Zubieta-Castillo, Gustavo; Zubieta-Calleja, Luis; Ardaya-Zubieta, Gustavo; Paulev, Poul-Erik

2011-01-01

As the oxygen tension of inspired air falls with increasing altitude in normal subjects, hyperventilation ensues. This acute respiratory alkalosis, induces increased renal excretion of bicarbonate, returning the pH back to normal, giving rise to compensated respiratory alkalosis or chronic hypocapnia. It seems a contradiction that so many normal people at high altitude should permanently live as chronic acid-base patients. Blood gas analyses of 1,865 subjects at 3,510 m, reported a P(a)CO(2) (arterial carbon dioxide tension ± SEM) = 29.4 ± 0.16 mmHg and pH = 7.40 ± 0.005. Base excess, calculated with the Van Slyke sea level equation, is -5 mM (milliMolar or mmol/l) as an average, suggesting chronic hypocapnia. THID, a new term replacing "Base Excess" is determined by titration to a pH of 7.40 at a P(a)CO(2) of 5.33 kPa (40 mmHg) at sea level, oxygen saturated and at 37°C blood temperature. Since our new modified Van Slyke equations operate with normal values for P(a)CO(2) at the actual altitude, a calculation of THID will always result in normal values-that is, zero.

Alternative approaches to treatment of Central Sleep Apnea

PubMed Central

2013-01-01

Synopsis Divergent approaches to treatment of hypocapnic central sleep apnea syndromes reflect the difficulties in taming a hyperactive respiratory chemoreflex. As both sleep fragmentation and a narrow CO2 reserve or increased loop gain drive the disease, sedatives (to induce longer periods of stable non-rapid eye movement (NREM) sleep and reduce the destabilizing effects of arousals in NREM sleep) and CO2-based stabilization approaches are logical. Adaptive ventilation reduces mean hyperventilation yet can induce ventilator-patient dyssynchrony, while enhanced expiratory rebreathing space (EERS, dead space during positive pressure therapy) and CO2 manipulation directly stabilize respiratory control by moving CO2 above the apnea threshold. Carbonic anhydrase inhibition can provide further adjunctive benefits. Provent and Winx may be less likely to trigger central apneas or periodic breathing in those with a narrow CO2 reserve. An oral appliance can meaningfully reduce positive pressure requirements and thus enable treatment of complex apnea. Novel pharmacological approaches may target mediators of carotid body glomus cell excitation, such as the balance between gas neurotransmitters. In complex apnea patients, single mode therapy is not always successful, and multi-modality therapy might need to be considered. Phenotyping of sleep apnea beyond conventional scoring approaches is the key to optimal management. PMID:24772053

Role of nocturnal rostral fluid shift in the pathogenesis of obstructive and central sleep apnoea.

PubMed

White, Laura H; Bradley, T Douglas

2013-03-01

Obstructive sleep apnoea (OSA) is common in the general population and increases the risk of motor vehicle accidents due to hypersomnolence from sleep disruption, and risk of cardiovascular diseases owing to repetitive hypoxia, sympathetic nervous system activation, and systemic inflammation. In contrast, central sleep apnoea (CSA) is rare in the general population. Although their pathogenesis is multifactorial, the prevalence of both OSA and CSA is increased in patients with fluid retaining states, especially heart failure, where they are associated with increased mortality risk. This observation suggests that fluid retention may contribute to the pathogenesis of both OSA and CSA. According to this hypothesis, during the day fluid accumulates in the intravascular and interstitial spaces of the legs due to gravity, and upon lying down at night redistributes rostrally, again owing to gravity. Some of this fluid may accumulate in the neck, increasing tissue pressure and causing the upper airway to narrow, thereby increasing its collapsibility and predisposing to OSA. In heart failure patients, with increased rostral fluid shift, fluid may additionally accumulate in the lungs, provoking hyperventilation and hypocapnia, driving below the apnoea threshold, leading to CSA. This review article will explore mechanisms by which overnight rostral fluid shift, and its prevention, can contribute to the pathogenesis and therapy of sleep apnoea.

Electroencephalographic features of benign adult familial myoclonic epilepsy.

PubMed

Toyota, Tomoko; Akamatsu, Naoki; Tanaka, Akihiro; Tsuji, Sadatoshi; Uozumi, Takenori

2014-02-01

To investigate electroencephalographic (EEG) features of benign adult familial myoclonic epilepsy (BAFME). We reviewed interictal EEG features in patients with BAFME treated between April 2005 and November 2012 at a tertiary referral center. The diagnostic criteria for BAFME were the presence of infrequent generalized tonic-clonic seizures, myoclonus or myoclonic seizures, and autosomal dominant inheritance. Interictal EEG findings of epilepsy with generalized tonic-clonic seizure only (EGTCS) were reviewed for comparison. We randomly selected 10 generalized spike/polyspike and wave complexes (GSW) for each BAFME patient and measured the duration of them. Photic stimulation and hyperventilation were performed in all. Nineteen (eight men, 11 women) patients with BAFME were included in this study. The mean frequency of GSW was 4.3±1.0Hz (mean±SD, n=14) in BAFME and 3.2±0.8Hz (n=10) in EGTCS. There was a statistically significant difference (p=0.008) between the two. Photoparoxysmal responses (PPR) were noted in 18 (95%) patients with BAFME but 1 (10%) with EGTCS. Faster frequency of GSW, compared with that in EGTCS, accompanied by PPR may be characteristic EEG features of BAFME. These findings may lead the diagnosis of BAFME. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Long-term efficacy and safety of lamotrigine monotherapy in Japanese and South Korean pediatric patients with newly diagnosed typical absence seizures: An open-label extension study.

PubMed

Yasumoto, Sawa; Ohtsuka, Yoko; Sato, Katsuaki; Kurata, Atsuyo; Numachi, Yotaro; Shimizu, Masahiro

2018-05-31

To investigate the efficacy and safety of long-term lamotrigine (LTG) monotherapy in Japanese and South Korean pediatric patients with newly diagnosed typical absence seizures. Six Japanese patients and one South Korean patient were enrolled in the extension phase of the study after completing the 12-week maintenance phase of an open-label clinical study of LTG monotherapy. During the extension phase, patients underwent efficacy and safety evaluation every 12 weeks. Of the seven patients, six patients completed the extension phase. The seizure-free rate confirmed by hyperventilation (HV)-electroencephalography ranged from 71.4% to 100.0% at each visit up to Week 168 of the extension phase. Similar effects were confirmed by HV-clinical signs and seizure diaries. Although no unexpected adverse events were observed, one Japanese patient was withdrawn from the extension phase due to mild drug-related rash developed 842 days after the start of LTG. Although the number of patients is limited, long-term LTG monotherapy appeared to be effective and generally well tolerated in Japanese and South Korean pediatric patients with typical absence seizures. Copyright © 2018 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

The venous-arterial difference in CO2 should be interpreted with caution in case of respiratory alkalosis in healthy volunteers.

PubMed

Morel, Jerome; Gergelé, Laurent; Dominé, Alexandre; Molliex, Serge; Perrot, Jean-Luc; Labeille, Bruno; Costes, Frederic

2017-08-01

The venous-arterial difference in CO 2 (ΔCO 2 ) has been proposed as an index of the adequacy of tissue perfusion in shock states. We hypothesized that the variation in PaCO 2 (hyper- or hypocapnia) could impact ΔCO 2 , partly through microcirculation adaptations. Fifteen healthy males volunteered to participate. For hypocapnia condition (hCO 2 ), the subjects were asked to hyperventilate, while they were asked to breathe a gas mixture containing 8 % CO 2 for hypercapnia condition (HCO 2 ). The 2 conditions were randomly assigned. Blood gases were measured at baseline before each condition, and after 5-7 min of either hCO 2 or HCO 2 condition. Microcirculation was assessed by the muscle reoxygenation slope measured with near infrared spectroscopy following a vascular occlusion test and by skin circulation with in vivo reflectance confocal microscopy. ΔCO 2 was significantly increased with hCO 2 while it tended to decrease with HCO 2 (non-significant). HCO 2 induced a moderate increase of the resaturation slope of NIRS oxygenation. Skin microcirculatory blood flow significantly dropped with hCO 2 , while it remained unchanged with hypercapnia. Our results warrant cautious interpretation of ΔCO 2 as an indicator of tissue perfusion during respiratory alkalosis.

Effects of respiratory alkalosis on human skeletal muscle metabolism at the onset of submaximal exercise.

PubMed

LeBlanc, P J; Parolin, M L; Jones, N L; Heigenhauser, G J F

2002-10-01

The purpose of this study was to examine the effects of respiratory alkalosis on human skeletal muscle metabolism at rest and during submaximal exercise. Subjects exercised on two occasions for 15 min at 55 % of their maximal oxygen uptake while either hyperventilating (R-Alk) or breathing normally (Con). Muscle biopsies were taken at rest and after 1 and 15 min of exercise. At rest, no effects on muscle metabolism were observed in response to R-Alk. In the first minute of exercise, there was a delayed activation of pyruvate dehydrogenase (PDH) in R-Alk compared with Con, resulting in a reduced rate of pyruvate oxidation. Also, glycogenolysis was higher in R-Alk compared with Con, which was attributed to a higher availability of the monoprotonated form of inorganic phosphate (P(i)), resulting in an elevated rate of pyruvate production. The mismatch between pyruvate production and its oxidation resulted in net lactate accumulation. These effects were not seen after 15 min of exercise, with no further differences in muscle metabolism between conditions. The results from the present study suggest that respiratory alkalosis may play an important role in lactate accumulation during the transition from rest to exercise in acute hypoxic conditions, but that other factors mediate lactate accumulation during steady-state exercise.

Effects of respiratory alkalosis on human skeletal muscle metabolism at the onset of submaximal exercise

PubMed Central

LeBlanc, P J; Parolin, M L; Jones, N L; Heigenhauser, G J F

2002-01-01

The purpose of this study was to examine the effects of respiratory alkalosis on human skeletal muscle metabolism at rest and during submaximal exercise. Subjects exercised on two occasions for 15 min at 55 % of their maximal oxygen uptake while either hyperventilating (R-Alk) or breathing normally (Con). Muscle biopsies were taken at rest and after 1 and 15 min of exercise. At rest, no effects on muscle metabolism were observed in response to R-Alk. In the first minute of exercise, there was a delayed activation of pyruvate dehydrogenase (PDH) in R-Alk compared with Con, resulting in a reduced rate of pyruvate oxidation. Also, glycogenolysis was higher in R-Alk compared with Con, which was attributed to a higher availability of the monoprotonated form of inorganic phosphate (Pi), resulting in an elevated rate of pyruvate production. The mismatch between pyruvate production and its oxidation resulted in net lactate accumulation. These effects were not seen after 15 min of exercise, with no further differences in muscle metabolism between conditions. The results from the present study suggest that respiratory alkalosis may play an important role in lactate accumulation during the transition from rest to exercise in acute hypoxic conditions, but that other factors mediate lactate accumulation during steady-state exercise. PMID:12356901

Inactivity-induced phrenic and hypoglossal motor facilitation are differentially expressed following intermittent vs. sustained neural apnea

PubMed Central

Baertsch, N. A.

2013-01-01

Reduced respiratory neural activity elicits a rebound increase in phrenic and hypoglossal motor output known as inactivity-induced phrenic and hypoglossal motor facilitation (iPMF and iHMF, respectively). We hypothesized that, similar to other forms of respiratory plasticity, iPMF and iHMF are pattern sensitive. Central respiratory neural activity was reversibly reduced in ventilated rats by hyperventilating below the CO2 apneic threshold to create brief intermittent neural apneas (5, ∼1.5 min each, separated by 5 min), a single brief massed neural apnea (7.5 min), or a single prolonged neural apnea (30 min). Upon restoration of respiratory neural activity, long-lasting (>60 min) iPMF was apparent following brief intermittent and prolonged, but not brief massed, neural apnea. Further, brief intermittent and prolonged neural apnea elicited an increase in the maximum phrenic response to high CO2, suggesting that iPMF is associated with an increase in phrenic dynamic range. By contrast, only prolonged neural apnea elicited iHMF, which was transient in duration (<15 min). Intermittent, massed, and prolonged neural apnea all elicited a modest transient facilitation of respiratory frequency. These results indicate that iPMF, but not iHMF, is pattern sensitive, and that the response to respiratory neural inactivity is motor pool specific. PMID:23493368

Laboratory, clinical and therapeutic features of respiratory panic disorder subtype.

PubMed

Zugliani, Morena M; Freire, Rafael C; Perna, Giampaolo; Crippa, Jose A; Nardi, Antonio E

2015-01-01

It is our aim to elaborate on the new developments in regard to the respiratory subtype (RS) of panic disorder (PD) since it was first described. We will present psychopathological features, diagnostic criteria, genetic and physiopathological hypotheses, as well as therapeutic and prognostic characteristics. Two searches were performed in the Thomson Reuters Web of Knowledge (http://wokinfo.com/): 1 - search terms: "panic disorder" AND ("respiratory symptom" OR "respiratory symptoms" OR "respiratory subtype" OR "respiratory panic" OR "cardiorespiratory"); 2 - all articles citing Briggs and colleagues' 1993 article "Subtyping of Panic Disorder by Symptom Profile" (Br J Psychiatry 1993;163: 201-9). Only those articles involving human subjects and written English were included. In comparison with patients of the non-respiratory subtype (NRS), RS patients showed greater familial history of PD, and higher comorbidity rates for anxiety disorders and depressive disorders. These patients were also more sensitive to CO2, hyperventilation and caffeine. Certain characteristics, such as heightened sensitivity to CO2 and the higher incidence of a family history of PD, clearly distinguished the Respiratory Subtype patients from the Non-Respiratory. Nonetheless, some studies failed to demonstrate differential responses to pharmacological treatment and CBT across the subtypes. RS patients seem to respond faster than NRS to pharmacological treatment with antidepressants and benzodiazepines, but more studies are needed to confirm this finding.

Respiratory modulation of human autonomic rhythms

NASA Technical Reports Server (NTRS)

Badra, L. J.; Cooke, W. H.; Hoag, J. B.; Crossman, A. A.; Kuusela, T. A.; Tahvanainen, K. U.; Eckberg, D. L.

2001-01-01

We studied the influence of three types of breathing [spontaneous, frequency controlled (0.25 Hz), and hyperventilation with 100% oxygen] and apnea on R-R interval, photoplethysmographic arterial pressure, and muscle sympathetic rhythms in nine healthy young adults. We integrated fast Fourier transform power spectra over low (0.05-0.15 Hz) and respiratory (0.15-0.3 Hz) frequencies; estimated vagal baroreceptor-cardiac reflex gain at low frequencies with cross-spectral techniques; and used partial coherence analysis to remove the influence of breathing from the R-R interval, systolic pressure, and muscle sympathetic nerve spectra. Coherence among signals varied as functions of both frequency and time. Partialization abolished the coherence among these signals at respiratory but not at low frequencies. The mode of breathing did not influence low-frequency oscillations, and they persisted during apnea. Our study documents the independence of low-frequency rhythms from respiratory activity and suggests that the close correlations that may exist among arterial pressures, R-R intervals, and muscle sympathetic nerve activity at respiratory frequencies result from the influence of respiration on these measures rather than from arterial baroreflex physiology. Most importantly, our results indicate that correlations among autonomic and hemodynamic rhythms vary over time and frequency, and, thus, are facultative rather than fixed.

Effects of improper source coupling in frequency-domain near-infrared spectroscopy

NASA Astrophysics Data System (ADS)

Noponen, T. E. J.; Kotilahti, K.; Nissilä, I.; Kajava, T.; Meriläinen, P. T.

2010-05-01

Currently, there is no widely used method to assess the reliability of contact between optodes and tissue in near-infrared spectroscopy (NIRS). In this study we observe a high linear dependence (R2 ~ 0.99) of the logarithmic modulation amplitude (ln(IAC)), average intensity (ln(IDC)) and phase (phi) on the source-detector distance (SDD) ranging from ~20 to 50 mm on human forehead measurements. The regression of phi is clearly reduced in measurements where light leakage occurs, mainly due to insufficient contact between the source optode and tissue. Utilizing this observation, a novel criterion to detect light leakage is developed. The criterion is applied to study the reliability of hemodynamic responses measured on the human forehead when breathing carbon dioxide-enriched air and during hyperventilation. The contrast of the signals is significantly lower in measurements which were adversely affected by light leakage. Furthermore, such unreliable signals at SDDs >= 50 mm correlate significantly (for \\rm [HbO_2] p < 0.01 and for [HbR] p < 0.001) better with the signals measured at SDDs < 20 mm. Using this method, poor contact between the source optode and tissue can be detected and corrected before the actual measurement, which enables us to avoid the acquisition of low contrast cortical signals.

Sensitivity of bronchopulmonary receptors to cold and heat mediated by transient receptor potential cation channel subtypes in an ex vivo rat lung preparation.

PubMed

Zhou, Yun; Sun, Biying; Li, Qian; Luo, Pin; Dong, Li; Rong, Weifang

2011-08-15

Changes in airway temperature can result in respiratory responses such as cough, bronchoconstriction and mucosal secretion after cold exposure and hyperventilation after heat exposure. In the present investigation, we examined the activity of bronchopulmonary receptors in response to activators of thermo-sensitive transient receptor potential (TS-TRP) cation channels using an ex vivo rat lung preparation. Receptive fields in small bronchioles were probed with von Frey hair monofilaments, warm (50°C) or cold (8°C) saline or saline containing TS-TRP agonists. Among 233 fibers tested, 159 (68.2%) responded to heat (50°C). A large proportion of heat-responsive receptors (107/145) were also activated by capsaicin. Heat and capsaicin-evoked responses were both blocked by TRPV1 antagonist, capsazepine. Only 15.3% of airway receptors responded to cold, which was associated with sensitivity to TRPM8 agonist menthol but not to TRPA1 agonist cinnamaldehyde (CA). Moreover, cold-evoked responses was unaffected by TRPA1 antagonist HC-03001. Our observations suggest that TRPV1 and TRPM8 are involved in transducing heat and cold in the lower respiratory tract, respectively. Copyright © 2011 Elsevier B.V. All rights reserved.

Role of nocturnal rostral fluid shift in the pathogenesis of obstructive and central sleep apnoea

PubMed Central

White, Laura H; Bradley, T Douglas

2013-01-01

Obstructive sleep apnoea (OSA) is common in the general population and increases the risk of motor vehicle accidents due to hypersomnolence from sleep disruption, and risk of cardiovascular diseases owing to repetitive hypoxia, sympathetic nervous system activation, and systemic inflammation. In contrast, central sleep apnoea (CSA) is rare in the general population. Although their pathogenesis is multifactorial, the prevalence of both OSA and CSA is increased in patients with fluid retaining states, especially heart failure, where they are associated with increased mortality risk. This observation suggests that fluid retention may contribute to the pathogenesis of both OSA and CSA. According to this hypothesis, during the day fluid accumulates in the intravascular and interstitial spaces of the legs due to gravity, and upon lying down at night redistributes rostrally, again owing to gravity. Some of this fluid may accumulate in the neck, increasing tissue pressure and causing the upper airway to narrow, thereby increasing its collapsibility and predisposing to OSA. In heart failure patients, with increased rostral fluid shift, fluid may additionally accumulate in the lungs, provoking hyperventilation and hypocapnia, driving below the apnoea threshold, leading to CSA. This review article will explore mechanisms by which overnight rostral fluid shift, and its prevention, can contribute to the pathogenesis and therapy of sleep apnoea. PMID:23230237

The emotional sequelae of whistleblowing: findings from a qualitative study.

PubMed

Peters, Kath; Luck, Lauretta; Hutchinson, Marie; Wilkes, Lesley; Andrew, Sharon; Jackson, Debra

2011-10-01

To highlight and illuminate the emotional sequelae of whistleblowing from whistleblowers and subjects of whistleblowing complaints. Whistleblowing has the potential to have a negative impact on individuals' physical and emotional well-being. However, few empirical studies have been conducted using qualitative methods to provide an in-depth exploration of the emotional consequences for those involved in whistleblowing incidents. Qualitative narrative inquiry design. Purposive sampling was used to recruit participants who had been involved in whistleblowing incidents. During interviews participants' accounts were digitally recorded and then transcribed verbatim. Data were then analysed by two researchers until consensus was reached. Findings revealed that participants' emotional health was considerably compromised as a result of the whistleblowing incident. Analysis of the data revealed the following dominant themes: 'I felt sad and depressed': overwhelming and persistent distress; 'I was having panic attacks and hyperventilating': acute anxiety; and, 'I had all this playing on my mind': nightmares, flashbacks and intrusive thoughts. While it has been previously acknowledged that whistleblowing has the potential to have a negative impact on all aspects of an individual's life, this study notably highlights the intensity of emotional symptoms suffered by participants as well as the extended duration of time these symptoms were apparent. As professionals, nurses, as well as organisations, have a responsibility to identify those who may be suffering the emotional trauma of whistleblowing and ensure they have access to appropriate resources. © 2011 Blackwell Publishing Ltd.

Altered Intermittent Rhythmic Delta and Theta Activity in the Electroencephalographies of High Functioning Adult Patients with Autism Spectrum Disorder

PubMed Central

Endres, Dominique; Maier, Simon; Feige, Bernd; Posielski, Nicole A.; Nickel, Kathrin; Ebert, Dieter; Riedel, Andreas; Philipsen, Alexandra; Perlov, Evgeniy; Tebartz van Elst, Ludger

2017-01-01

Background: Autism spectrum disorder (ASD) is often associated with epilepsy. Previous studies have also shown increased rates of electroencephalographic (EEG) alteration in ASD patients without epilepsy. The aim of this study was to compare the rate of intermittent rhythmic delta and theta activity (IRDA/IRTA) events between high-functioning adult patients with ASD and matched healthy controls. Materials and Methods: Routine EEG records of 19 ASD patients and 19 matched controls were screened for IRDA/IRTA using a fully data driven analysis with fixed thresholds. IRDA/IRTA rates before and after hyperventilation (HV) as well as the HV-induced difference in IRDA/IRTA rates (HV difference) were analyzed. For inter-group measures, we used the Wilcoxon rank sum test. Results: Significantly increased HV difference was detected in the ASD group (p = 0.0497). However, the groups showed no difference in IRDA/IRTA rates before HV (p = 0.564) and after HV (p = 0.163). Conclusions: The lack of any group differences regarding IRDA/IRTA before HV might be related to the fact that we only studied non-secondary high-functioning autism in a small sample of epilepsy-free adult patients. A significantly increased HV difference might be regarded as a marker of subtle neuronal network instability possibly causing short-term disturbances via local area network inhibition and long-term effects via epileptic encephalopathy. PMID:28265243

[Electrophysiological correlates of efficacy of nootropic drugs in the treatment of consequences of traumatic brain injury in adolescents].

PubMed

Iznak, E V; Iznak, A F; Pankratova, E A; Zavadenko, N N; Guzilova, L S; Guzilova, Iu I

2010-01-01

To assess objectively a dynamics of brain functional state, EEG spectral power and peak latency of the P300 component of cognitive auditory evoked potentials have been analyzed in adolescents during the course of nootropic therapy of residual asthenic consequences of traumatic brain injury (ICD-10 F07.2). The study included 76 adolescents, aged 12-18 years, who have undergone severe closed head trauma with brain commotion 1/2--5 years ago. Patients have been divided into 3 groups treated during one month with cerebrolysin, piracetam or magne-B6, respectively. After the end of the nootropic therapy, 77% of patients treated with cerebrolysin as well as 50% of patients treated with piracetam and magne-B6 have demonstrated the positive dynamics of their brain functional state that manifested itself in the appearance of occipital EEG alpha rhythm or in the increase of its spectral power; in the normalization of alpha rhythm frequency; in the decrease in the spectral power of slow wave (theta and delta) EEG activity, in the amount (up to the disappearance) of paroxysmal EEG activity, in the EEG response to hyperventilation and in the shortening of the P300 peak latency. Such positive changes of neurophysiological parameters have been associated with the improvement of clinical conditions of patients and correlated significantly with the dynamics of psychometric scores of attention and memory.

PaCO2 measurement in cerebral haemodynamics: face mask or nasal cannulae?

PubMed

Minhas, J S; Robinson, T; Panerai, R

2017-06-22

PaCO 2 affects cerebral blood flow (CBF) and its regulatory mechanisms, but the effects of CO 2 measurement technique on cerebrovascular parameters are unknown. In order to determine if the two most commonly used approaches, face mask (FM) or nasal cannulae (NC), are interchangeable or not, we tested the hypothesis that the use of FM versus NC does not lead to significant differences in CO 2 -related systemic and cerebrovascular parameters. Recordings of CBF velocity (CBFV), blood pressure (BP), heart rate, and end-tidal CO 2 (EtCO 2 ) were performed in 42 subjects during normocapnia (FM or NC) and 5% CO 2 inhalation (FM) or hyperventilation (NC). Dynamic cerebral autoregulation was assessed with the autoregulation index (ARI), derived by transfer function analysis from the CBFV response to a hypothetical step change in BP. Significant differences in physiological parameters were seen between FM and NC: EtCO 2 (37.40 versus 35.26 mmHg, p  =  0.001) and heart rate (69.6 versus 66.7 bpm, p  =  0.001) respectively. No differences were observed for mean BP, CBFV or the ARI index. Use of FM or NC for measurement of EtCO 2 leads to physiological changes and differences in parameter values that need to be taken into consideration when interpreting and/or comparing results in studies of cerebral haemodynamics.

Stimulation of the basal and central amygdala in the mustached bat triggers echolocation and agonistic vocalizations within multimodal output

PubMed Central

Ma, Jie; Kanwal, Jagmeet S.

2014-01-01

The neural substrate for the perception of vocalizations is relatively well described, but how their timing and specificity are tightly coupled with accompanying physiological changes and context-appropriate behaviors remains unresolved. We hypothesized that temporally integrated vocal and emotive responses, especially the expression of fear, vigilance and aggression, originate within the amygdala. To test this hypothesis, we performed electrical microstimulation at 461 highly restricted loci within the basal and central amygdala in awake mustached bats. At a subset of these sites, high frequency stimulation with weak constant current pulses presented at near-threshold levels triggered vocalization of either echolocation pulses or social calls. At the vast majority of locations, microstimulation produced a constellation of changes in autonomic and somatomotor outputs. These changes included widespread co-activation of significant tachycardia and hyperventilation and/or rhythmic ear pinna movements (PMs). In a few locations, responses were constrained to vocalization and/or PMs despite increases in the intensity of stimulation. The probability of eliciting echolocation pulses vs. social calls decreased in a medial-posterior to anterolateral direction within the centrobasal amygdala. Microinjections of kainic acid (KA) at stimulation sites confirmed the contribution of cellular activity rather than fibers-of-passage in the control of multimodal outputs. The results suggest that localized clusters of neurons may simultaneously modulate the activity of multiple central pattern generators (CPGs) present within the brainstem. PMID:24624089

Stimulation of the basal and central amygdala in the mustached bat triggers echolocation and agonistic vocalizations within multimodal output.

PubMed

Ma, Jie; Kanwal, Jagmeet S

2014-01-01

The neural substrate for the perception of vocalizations is relatively well described, but how their timing and specificity are tightly coupled with accompanying physiological changes and context-appropriate behaviors remains unresolved. We hypothesized that temporally integrated vocal and emotive responses, especially the expression of fear, vigilance and aggression, originate within the amygdala. To test this hypothesis, we performed electrical microstimulation at 461 highly restricted loci within the basal and central amygdala in awake mustached bats. At a subset of these sites, high frequency stimulation with weak constant current pulses presented at near-threshold levels triggered vocalization of either echolocation pulses or social calls. At the vast majority of locations, microstimulation produced a constellation of changes in autonomic and somatomotor outputs. These changes included widespread co-activation of significant tachycardia and hyperventilation and/or rhythmic ear pinna movements (PMs). In a few locations, responses were constrained to vocalization and/or PMs despite increases in the intensity of stimulation. The probability of eliciting echolocation pulses vs. social calls decreased in a medial-posterior to anterolateral direction within the centrobasal amygdala. Microinjections of kainic acid (KA) at stimulation sites confirmed the contribution of cellular activity rather than fibers-of-passage in the control of multimodal outputs. The results suggest that localized clusters of neurons may simultaneously modulate the activity of multiple central pattern generators (CPGs) present within the brainstem.

Preoperative assessment and preparation of patients with diseases affecting the central nervous system.

PubMed

Milaković, Branko; Dimitrijević, Ivan; Malenković, Vesna; Marković, Dejan; Pantić-Palibrk, Vesna; Gvozdenović, Ljiljana

2011-01-01

This review will examine the most important issues of preoperative evaluation and preparation in relation to patients with deseases affecting the central nervous system. Those patients may undergo various forms of surgery unrelated to the central nervous system disease. We discuss the effect of physiologic and pharmacological factors on cerebral autoregulation and control of intracranial pressure alongside its clinical relevance with the help of new evidence. Regardless of the reason for surgery, coexisting diseases of brain often have important implications when selecting anesthetic drugs, procedures and monitoring techniques. Suppression of cerebral metabolic rate is not the sole mechanism for the neuroprotective effect of anaesthetic agents. There are certain general principles, but also some specific circumstances, when we are talking about optimal anesthetic procedure for a patient with coexisting brain disease. Intravenous anesthesia, such as combination of propofol and remifentanil, provides best preservation of autoregulation. Among inhaled agents isoflurane and sevoflurane appear to preserve autoregulation at all doses, whereas with other agents autoregulation is impaired in a dose-related manner. During maintenance of anesthesia the patient is ventilated by intermittent positive pressure ventilation, at intermediate hyperventilation (PaCO2 25-30 mmHg). Intraoperative cerebral autoregulation monitoring is an important consideration for the patients with coexisting neurological disease. Transcranial Doppler based static autoregulation measurements appears to be the most robust bedside method for this purpose.

'Ome' on the range: update on high-altitude acclimatization/adaptation and disease.

PubMed

Luo, Yongjun; Wang, Yuxiao; Lu, Hongxiang; Gao, Yuqi

2014-11-01

The main physiological challenge in high-altitude plateau environments is hypoxia. When people living in a plain environment migrate to the plateau, they face the threat of hypoxia. Most people can acclimatize to high altitudes; the acclimatization process mainly consists of short-term hyperventilation and long-term compensation by increased oxygen uptake, transport, and use due to increased red blood cell mass, myoglobin, and mitochondria. If individuals cannot acclimatize to high altitude, they may suffer from a high-altitude disease, such as acute mountain disease (AMS), high-altitude pulmonary edema (HAPE), high-altitude cerebral edema (HACE) or chronic mountain sickness (CMS). Because some individuals are more susceptible to high altitude diseases than others, the incidence of these high-altitude diseases is variable and cannot be predicted. Studying "omes" using genomics, proteomics, metabolomics, transcriptomics, lipidomics, immunomics, glycomics and RNomics can help us understand the factors that mediate susceptibility to high altitude illnesses. Moreover, analysis of the "omes" using a systems biology approach may provide a greater understanding of high-altitude illness pathogenesis and improve the efficiency of the diagnosis and treatment of high-altitude illnesses in the future. Below, we summarize the current literature regarding the role of "omes" in high-altitude acclimatization/adaptation and disease and discuss key research gaps to better understand the contribution of "omes" to high-altitude illness susceptibility.

Potential of in vivo real-time gastric gas profiling: a pilot evaluation of heat-stress and modulating dietary cinnamon effect in an animal model

NASA Astrophysics Data System (ADS)

Ou, Jian Zhen; Cottrell, Jeremy J.; Ha, Nam; Pillai, Naresh; Yao, Chu K.; Berean, Kyle J.; Ward, Stephanie A.; Grando, Danilla; Muir, Jane G.; Harrison, Christopher J.; Wijesiriwardana, Udani; Dunshea, Frank R.; Gibson, Peter R.; Kalantar-Zadeh, Kourosh

2016-09-01

Gastroenterologists are still unable to differentiate between some of the most ordinary disorders of the gut and consequently patients are misdiagnosed. We have developed a swallowable gas sensor capsule for addressing this. The gases of the gut are the by-product of the fermentation processes during digestion, affected by the gut state and can consequently provide the needed information regarding the health of the gut. Here we present the first study on gas sensor capsules for revealing the effect of a medical supplement in an animal (pig) model. We characterise the real-time alterations of gastric-gas in response to environmental heat-stress and dietary cinnamon and use the gas profiles for understanding the bio-physiological changes. Under no heat-stress, feeding increases gastric CO2 concentration, while dietary cinnamon reduces it due to decrease in gastric acid and pepsin secretion. Alternatively, heat-stress leads to hyperventilation in pigs, which reduces CO2 concentration and with the cinnamon treatment, CO2 diminishes even more, resulting in health improvement outcomes. Overall, a good repeatability in gas profiles is also observed. The model demonstrates the strong potential of real-time gas profiler in providing new physiological information that will impact understanding of therapeutics, presenting a highly reliable device for monitoring/diagnostics of gastrointestinal disorders.

Potential of in vivo real-time gastric gas profiling: a pilot evaluation of heat-stress and modulating dietary cinnamon effect in an animal model.

PubMed

Ou, Jian Zhen; Cottrell, Jeremy J; Ha, Nam; Pillai, Naresh; Yao, Chu K; Berean, Kyle J; Ward, Stephanie A; Grando, Danilla; Muir, Jane G; Harrison, Christopher J; Wijesiriwardana, Udani; Dunshea, Frank R; Gibson, Peter R; Kalantar-Zadeh, Kourosh

2016-09-16

Gastroenterologists are still unable to differentiate between some of the most ordinary disorders of the gut and consequently patients are misdiagnosed. We have developed a swallowable gas sensor capsule for addressing this. The gases of the gut are the by-product of the fermentation processes during digestion, affected by the gut state and can consequently provide the needed information regarding the health of the gut. Here we present the first study on gas sensor capsules for revealing the effect of a medical supplement in an animal (pig) model. We characterise the real-time alterations of gastric-gas in response to environmental heat-stress and dietary cinnamon and use the gas profiles for understanding the bio-physiological changes. Under no heat-stress, feeding increases gastric CO2 concentration, while dietary cinnamon reduces it due to decrease in gastric acid and pepsin secretion. Alternatively, heat-stress leads to hyperventilation in pigs, which reduces CO2 concentration and with the cinnamon treatment, CO2 diminishes even more, resulting in health improvement outcomes. Overall, a good repeatability in gas profiles is also observed. The model demonstrates the strong potential of real-time gas profiler in providing new physiological information that will impact understanding of therapeutics, presenting a highly reliable device for monitoring/diagnostics of gastrointestinal disorders.

Low pre-treatment end-tidal CO2 predicts dropout from cognitive-behavioral therapy for anxiety and related disorders.

PubMed

Tolin, David F; Billingsley, Amber L; Hallion, Lauren S; Diefenbach, Gretchen J

2017-03-01

Recent clinical trial research suggests that baseline low end-tidal CO 2 (ETCO 2 , the biological marker of hyperventilation) may predict poorer response to cognitive-behavioral therapy (CBT) for anxiety-related disorders. The present study examined the predictive value of baseline ETCO 2 among patients treated for such disorders in a naturalistic clinical setting. Sixty-nine adults with a primary diagnosis of a DSM-5 anxiety disorder, obsessive-compulsive disorder, or posttraumatic stress disorder completed a 4-min assessment of resting ETCO 2 , and respiration rate (the first minute was analyzed). Lower ETCO 2 was not associated with a diagnosis of panic disorder, and was associated with lower subjective distress ratings on certain measures. Baseline ETCO 2 significantly predicted treatment dropout: those meeting cutoff criteria for hypocapnia were more than twice as likely to drop out of treatment, and ETCO 2 significantly predicted dropout beyond other pre-treatment variables. Weekly measurement suggested that the lower-ETCO 2 patients who dropped out were not responding well to treatment prior to dropout. The present results, along with previous clinical trial data, suggest that lower pre-treatment ETCO 2 is a negative prognostic indicator for CBT for anxiety-related disorders. It is suggested that patients with lower ETCO 2 might benefit from additional intervention that targets respiratory abnormality. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cerebral monitoring during cardiopulmonary bypass in children.

PubMed

Kern, F H; Schell, R M; Greeley, W J

1993-07-01

Although cerebral monitoring during CPB remains primarily investigational, recent data support its clinical utility. In particular, it is cerebral metabolic monitoring that provides meaningful information in terms of preparing the brain for dhCPB and dhCA. Cerebral blood flow or cerebral blood flow velocity monitoring is less beneficial due to the presence of luxuriant cerebral blood flow at deep hypothermic temperatures. Conventional temperature monitoring can be improved upon by adding jugular venous oxygen saturation monitoring to satisfy the primary goal of cerebral protection--uniform cerebral cooling and metabolic suppression. Although online measures of cerebral cellular metabolism are not widely available, early experience with near infrared technology suggests that it is a feasible and reliable monitor of cerebral metabolic activity and is likely to represent an important noninvasive continuous monitor in the near future. CMRO2 recovery data have suggested that cerebral metabolic suppression is more severe the longer the period of dhCA. Cerebral protection strategies, such as intermittent cerebral perfusion have demonstrated less metabolic suppression of dhCA in animal models and are currently undergoing clinical evaluation in our institution. Finally, the postoperative period remains a high-risk period for neurologic injury because temperatures are normothermic, cardiac output is reduced, cerebral autoregulation is impaired, and management strategies, such as hyperventilation, are commonly used to increase pulmonary blood flow with little knowledge on its effects on cerebral perfusion.

Cardiac output variations in supine resting subjects during head-out cold water immersion.

PubMed

Vogelaere, P; Deklunder, G; Lecroart, J

1995-08-01

Five men, aged 31.2 years (SD 2.3), under semi-nude conditions and resting in a dorsal reclining position, were exposed to thermoneutral air for 30 min, followed immediately by a cold water (15 degrees C) immersion for 60 min. Cardiac output was measured using a dual-beam Doppler flow meter. During immersion in cold water, cardiac frequency (fc) showed an initial bradycardia. The lowest values were reached at about 10 min after immersion, 58.3 (SD 2.5) to 48.3 (SD 7.8) beats min-1 (P < 0.05). By the 20th min of exposure, fc had gradually risen to 70.0 beats min-1 (SD 6.6, P < 0.05). This change could be due to the inhibition of the initial vagal reflex by increased catecholamine concentration. Stroke volume (Vs) was significantly increased (P < 0.05) during the whole cold immersion period. Cardiac output, increased from 3.57 (SD 0.50) to 6.26 (SD 1.33) l min-1 (P < 0.05) and its change with time was a function of both Vs and fc. On the other hand, systolic flow acceleration was unchanged during the period of immersion. The changes in the respiratory variables (ventilation, oxygen uptake, carbon dioxide output and respiratory exchange ratio) during immersion showed an initial hyperventilation followed, as immersion proceeded, by a slower metabolic increase due to shivering.

Potential of in vivo real-time gastric gas profiling: a pilot evaluation of heat-stress and modulating dietary cinnamon effect in an animal model

PubMed Central

Ou, Jian Zhen; Cottrell, Jeremy J.; Ha, Nam; Pillai, Naresh; Yao, Chu K.; Berean, Kyle J.; Ward, Stephanie A.; Grando, Danilla; Muir, Jane G.; Harrison, Christopher J.; Wijesiriwardana, Udani; Dunshea, Frank R.; Gibson, Peter R.; Kalantar-zadeh, Kourosh

2016-01-01

Gastroenterologists are still unable to differentiate between some of the most ordinary disorders of the gut and consequently patients are misdiagnosed. We have developed a swallowable gas sensor capsule for addressing this. The gases of the gut are the by-product of the fermentation processes during digestion, affected by the gut state and can consequently provide the needed information regarding the health of the gut. Here we present the first study on gas sensor capsules for revealing the effect of a medical supplement in an animal (pig) model. We characterise the real-time alterations of gastric-gas in response to environmental heat-stress and dietary cinnamon and use the gas profiles for understanding the bio-physiological changes. Under no heat-stress, feeding increases gastric CO2 concentration, while dietary cinnamon reduces it due to decrease in gastric acid and pepsin secretion. Alternatively, heat-stress leads to hyperventilation in pigs, which reduces CO2 concentration and with the cinnamon treatment, CO2 diminishes even more, resulting in health improvement outcomes. Overall, a good repeatability in gas profiles is also observed. The model demonstrates the strong potential of real-time gas profiler in providing new physiological information that will impact understanding of therapeutics, presenting a highly reliable device for monitoring/diagnostics of gastrointestinal disorders. PMID:27633400

The effect of a holistic self-management plan on asthma control.

PubMed

Grammatopoulou, Eirini; Skordilis, Emmanouil K; Haniotou, Aikaterini; John, Zarotis; Athanasopoulos, Spyros

2017-08-01

The holistic self-management plan includes lifelong actions that enable patients to cope with their disease. The present study was designed to evaluate the effect of a holistic self-management plan on asthma control. A 12-month controlled study was conducted. Adult patients with mild-to-moderate asthma (n = 24) who attended the emergency asthma department were randomized to two groups: One group followed four educational sessions and three personal home sessions (n = 12), while a second group received a short manual with asthma information (n = 12). The main measure was the asthma control test (ACT), while secondary outcomes were self-efficacy (general self-efficacy scale, GSE), end-tidal carbon dioxide (ETCO 2 ), respiratory rate (RR), breathing hold time (BHT), the Nijmegen Questionnaire (NQ), and spirometry (FEV 1 % predicted (forced expiratory volume in 1 second % predicted)) scores. The 2 × 4 ANOVA showed a significant interaction effect between intervention and time in ACT (p = 0.001), GSE (p < 0.001), ETCO 2 (p < 0.001), RR (p < 0.001), BHT (p < 0.001), NQ (p = 0.05), and FEV 1 % predicted (p < 0.001). Predictors of asthma control were self-efficacy and ETCO 2 . In conclusion, this exploratory study provided support for the effectiveness of holistic self-management in asthma control. Behavioral changes, as indicated by the development of self-efficacy and the reduction of hyperventilation, contributed to the effectiveness of the intervention.

Intraspecific Variation of Centruroides Edwardsii Venom from Two Regions of Colombia

PubMed Central

Estrada-Gómez, Sebastián; Cupitra, Nelson Ivan; Arango, Walter Murillo; Vargas Muñoz, Leidy Johana

2014-01-01

We report the first description studies, partial characterization, and intraspecific difference of Centruroides edwardsii, Gervais 1843, venom. C. edwardsii from two Colombian regions (Antioquia and Tolima) were evaluated. Both venoms showed hemolytic activity, possibly dependent of enzymatic active phospholipases, and neither coagulant nor proteolytic activities were observed. Venom electrophoretic profile showed significant differences between C. edwardsii venom from both regions. A high concentration of proteins with molecular masses between 31 kDa and 97.4 kDa, and an important concentration close or below 14.4 kDa were detected. RP-HPLC retention times between 38.2 min and 42.1 min, showed bands close to 14.4 kDa, which may correspond to phospholipases. RP-HPLC venom profile showed a well conserved region in both venoms between 7 and 17 min, after this, significant differences were detected. From Tolima region venom, 50 well-defined peaks were detected, while in the Antioquia region venom, 55 well-defined peaks were detected. Larvicidal activity was only detected in the C. edwardsii venom from Antioquia. No antimicrobial activity was observed using complete venom or RP-HPLC collected fractions of both venoms. Lethally activity (carried out on female albino swiss mice) was detected at doses over 19.2 mg/kg of crude venom. Toxic effects included distress, excitability, eye irritation and secretions, hyperventilation, ataxia, paralysis, and salivation. PMID:25025710

Cardiorespiratory responses in an Antarctic fish suggest limited capacity for thermal acclimation.

PubMed

Egginton, Stuart; Campbell, Hamish A

2016-05-01

Polar fishes are at high risk from increasing seawater temperatures. Characterising the physiological responses to such changes may both clarify mechanisms that permit life under extreme conditions and identify limitations in the response to continued global warming. We hypothesised that Notothenia coriiceps would show physiological compensation after an acute exposure to 5°C, and following 6 weeks warm acclimation, compared with ambient temperature (0°C). However, initial tachycardia (22.4±2.8 versus 12.8±1.1 min(-1); P<0.01) was not reversed by acclimation (21.0±1.9 min(-1)). Hyperventilation (45.5±3.1 versus 21.4±2.4 breaths min(-1); P<0.001) showed a modest reduction following acclimation (38.0±2.9 min(-1); P<0.05), while resting oxygen consumption (0.52±0.08 mmol kg(-1) h(-1)) was acutely increased at 5°C (1.07±0.10 mmol kg(-1) h(-1); P<0.001) but unchanged with acclimation. Autonomic blockade showed initial responses were mainly of vagal origin, with little subsequent withdrawal or recovery in long-term heart rate variability after 6 weeks. Given the limited cardiorespiratory capacity to withstand sustained warming, effective physiological compensation probably requires a more prolonged acclimation period. © 2016. Published by The Company of Biologists Ltd.

Gill remodelling during terrestrial acclimation reduces aquatic respiratory function of the amphibious fish Kryptolebias marmoratus.

PubMed

Turko, Andy J; Cooper, Chris A; Wright, Patricia A

2012-11-15

The skin-breathing amphibious fish Kryptolebias marmoratus experiences rapid environmental changes when moving between water- and air-breathing, but remodelling of respiratory morphology is slower (~1 week). We tested the hypotheses that (1) there is a trade-off in respiratory function of gills displaying aquatic versus terrestrial morphologies and (2) rapidly increased gill ventilation is a mechanism to compensate for reduced aquatic respiratory function. Gill surface area, which varied inversely to the height of the interlamellar cell mass, was increased by acclimating fish for 1 week to air or low ion water, or decreased by acclimating fish for 1 week to hypoxia (~20% dissolved oxygen saturation). Fish were subsequently challenged with acute hypoxia, and gill ventilation or oxygen uptake was measured. Fish with reduced gill surface area increased ventilation at higher dissolved oxygen levels, showed an increased critical partial pressure of oxygen and suffered impaired recovery compared with brackish water control fish. These results indicate that hyperventilation, a rapid compensatory mechanism, was only able to maintain oxygen uptake during moderate hypoxia in fish that had remodelled their gills for land. Thus, fish moving between aquatic and terrestrial habitats may benefit from cutaneously breathing oxygen-rich air, but upon return to water must compensate for a less efficient branchial morphology (mild hypoxia) or suffer impaired respiratory function (severe hypoxia).

Cardiac output variations in supine resting subjects during head-out cold water immersion

NASA Astrophysics Data System (ADS)

Vogelaere, P.; Deklunder, G.; Lecroart, J.

1995-03-01

Five men, aged 31.2 years (SD 2.3), under semi-nude conditions and resting in a dorsal reclining position, were exposed to thermoneutral air for 30 min, followed immediately by a cold water (15°C) immersion for 60 min. Cardiac output was measured using a dualbeam Doppler flow meter. During immersion in cold water, cardiac frequency ( f c) showed an initial bradycardia. The lowest values were reached at about 10 min after immersion, 58.3 (SD 2.5) to 48.3 (SD 7.8) beats min-1 ( P < 0.05). By the 20th min of exposure, f c had gradually risen to 70.0 beats min-1 (SD 6.6, P < 0.05). This change could be due to the inhibition of the initial vagal reflex by increased catecholamine concentration. Stroke volume ( V s) was significantly increased ( P < 0.05) during the whole cold immersion period. Cardiac output, increased from 3.57 (SD 0.50) to 6.26 (SD 1.33)1 min-1 ( P < 0.05) and its change with time was a function of both V s and f c. On the other hand, systolic flow acceleration was unchanged during the period of immersion. The changes in the respiratory variables (ventilation, oxygen uptake, carbon dioxide output and respiratory exchange ratio) during immersion showed an initial hyperventilation followed, as immersion proceeded, by a slower metabolic increase due to shivering.

Anaesthesia for electroconvulsive therapy - new tricks for old drugs: a systematic review.

PubMed

Stripp, Tobias Kvist; Jorgensen, Martin Balslev; Olsen, Niels Vidiendal

2018-04-01

The objective of this review is to investigate existing literature in order to delineate whether the use of anaesthesia and timing of seizure induction in a new and optimised way may improve the efficacy of electroconvulsive therapy (ECT). PubMed/MEDLINE was searched for existing literature, last search on 24 June 2015. Relevant clinical studies on human subjects involving choice of anaesthetic, ventilation and bispectral index (BIS) monitoring in the ECT setting were considered. The references of relevant studies were likewise considered. Propofol yields the shortest seizures, etomidate and ketamine the longest. Etomidate and ketamine+propofol 1 : 1 seems to yield the seizures with best quality. Seizure quality is improved when induction of ECT is delayed until the effect of the anaesthetic has waned - possibly monitored with BIS values. Manual hyperventilation with 100% O2 may increase the pO2/pCO2-ratio, which may be correlated with better seizure quality. Etomidate or a 1 : 1 ketamine and propofol combination may be the best method to achieve general anaesthesia in the ECT setting. There is a need for large randomised prospective studies comparing the effect of methohexital, thiopental, propofol, ketamine, propofol+ketamine 1 : 1 and etomidate in the ECT treatment of major depressed patients. These studies should investigate safety and side effects, and most importantly have antidepressant efficacy and cognitive side effects as outcome measures instead of seizure quality.

Reflex respiratory and cardiovascular effects of stimulation of receptors in the nose of the dog.

PubMed

James, J E; De Burgh Daly, M

1972-02-01

1. In forty-one out of forty-seven dogs under chloralose-urethane or Nembutal anaesthesia, mechanical stimulation of the nasal mucous membrane caused a reduction or inhibition of respiration, bradycardia, variable changes of arterial blood pressure, and a small rise in venous pressure.2. Simultaneous measurements of arterial and venous pressures, and also of blood flow in various arteries by means of an electromagnetic flowmeter indicate that the calculated vascular resistance increases in the intact limb, muscle, and skin, and the vascular beds of the vertebral, superior mesenteric, renal and splenic arteries. No changes in vascular resistance occur in the common carotid circulation.3. Evidence is presented that the increase in vascular resistance is due to vasoconstriction, and occurs in the absence of changes in pulmonary ventilation.4. Stimulation of the nasal mucous membrane causes a reduction in volume of the spleen.5. The respiratory and cardiovascular responses are reflex in nature, being abolished by the application of a local anaesthetic to the nose or by combined division of the maxillary and ethmoidal branches of the trigeminal nerves. The cardiac response is mediated largely by the vagus nerves, and the vascular responses by sympathetic adrenergic fibres.6. Cessation of the stimulus to the nose not infrequently results in the following temporary after-effects: hyperventilation, tachycardia, hypertension, and vasodilatation in the intact limb and in muscle.

Cerebral versus systemic hemodynamics during graded orthostatic stress in humans

NASA Technical Reports Server (NTRS)

Levine, B. D.; Giller, C. A.; Lane, L. D.; Buckey, J. C.; Blomqvist, C. G.

1994-01-01

BACKGROUND: Orthostatic syncope is usually attributed to cerebral hypoperfusion secondary to systemic hemodynamic collapse. Recent research in patients with neurocardiogenic syncope has suggested that cerebral vasoconstriction may occur during orthostatic hypotension, compromising cerebral autoregulation and possibly contributing to the loss of consciousness. However, the regulation of cerebral blood flow (CBF) in such patients may be quite different from that of healthy individuals, particularly when assessed during the rapidly changing hemodynamic conditions associated with neurocardiogenic syncope. To be able to interpret the pathophysiological significance of these observations, a clear understanding of the normal responses of the cerebral circulation to orthostatic stress must be obtained, particularly in the context of the known changes in systemic and regional distributions of blood flow and vascular resistance during orthostasis. Therefore, the specific aim of this study was to examine the changes that occur in the cerebral circulation during graded reductions in central blood volume in the absence of systemic hypotension in healthy humans. We hypothesized that cerebral vasoconstriction would occur and CBF would decrease due to activation of the sympathetic nervous system. We further hypothesized, however, that the magnitude of this change would be small compared with changes in systemic or skeletal muscle vascular resistance in healthy subjects with intact autoregulation and would be unlikely to cause syncope without concomitant hypotension. METHODS AND RESULTS: To test this hypothesis, we studied 13 healthy men (age, 27 +/- 7 years) during progressive lower body negative pressure (LBNP). We measured systemic flow (Qc is cardiac output; C2H2 rebreathing), regional forearm flow (FBF; venous occlusion plethysmography), and blood pressure (BP; Finapres) and calculated systemic (SVR) and forearm (FVR) vascular resistances. Changes in brain blood flow were estimated from changes in the blood flow velocity in the middle cerebral artery (VMCA) using transcranial Doppler. Pulsatility (systolic minus diastolic/mean velocity) normalized for systemic arterial pressure pulsatility was used as an index of distal cerebral vascular resistance. End-tidal PACO2 was closely monitored during LBNP. From rest to maximal LBNP before the onset of symptoms or systemic hypotension, Qc and FBF decreased by 29.9% and 34.4%, respectively. VMCA decreased less, by 15.5% consistent with a smaller decrease in CBF. Similarly, SVR and FVR increased by 62.8% and 69.8%, respectively, whereas pulsatility increased by 17.2%, suggestive of a mild degree of small-vessel cerebral vasoconstriction. Seven of 13 subjects had presyncope during LBNP, all associated with a sudden drop in BP (29 +/- 9%). By comparison, hyperventilation alone caused greater changes in VMCA (42 +/- 2%) and pulsatility but never caused presyncope. In a separate group of 3 subjects, superimposition of hyperventilation during highlevel LBNP caused a further decrease in VMCA (31 +/- 7%) but no change in BP or level of consciousness. CONCLUSIONS: We conclude that cerebral vasoconstriction occurs in healthy humans during graded reductions in central blood volume caused by LBNP. However, the magnitude of this response is small compared with changes in SVR or FVR during LBNP or other stimuli known to induce cerebral vasoconstriction (hypocapnia). We speculate that this degree of cerebral vasoconstriction is not by itself sufficient to cause syncope during orthostatic stress. However, it may exacerbate the decrease in CBF associated with hypotension if hemodynamic instability develops.

Automatic interpretation and writing report of the adult waking electroencephalogram.

PubMed

Shibasaki, Hiroshi; Nakamura, Masatoshi; Sugi, Takenao; Nishida, Shigeto; Nagamine, Takashi; Ikeda, Akio

2014-06-01

Automatic interpretation of the EEG has so far been faced with significant difficulties because of a large amount of spatial as well as temporal information contained in the EEG, continuous fluctuation of the background activity depending on changes in the subject's vigilance and attention level, the occurrence of paroxysmal activities such as spikes and spike-and-slow-waves, contamination of the EEG with a variety of artefacts and the use of different recording electrodes and montages. Therefore, previous attempts of automatic EEG interpretation have been focussed only on a specific EEG feature such as paroxysmal abnormalities, delta waves, sleep stages and artefact detection. As a result of a long-standing cooperation between clinical neurophysiologists and system engineers, we report for the first time on a comprehensive, computer-assisted, automatic interpretation of the adult waking EEG. This system analyses the background activity, intermittent abnormalities, artefacts and the level of vigilance and attention of the subject, and automatically presents its report in written form. Besides, it also detects paroxysmal abnormalities and evaluates the effects of intermittent photic stimulation and hyperventilation on the EEG. This system of automatic EEG interpretation was formed by adopting the strategy that the qualified EEGers employ for the systematic visual inspection. This system can be used as a supplementary tool for the EEGer's visual inspection, and for educating EEG trainees and EEG technicians. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

6th Yahya Cohen Lecture: visual experience during cataract surgery.

PubMed

Au Eong, K G

2002-09-01

The visual sensations many patients experience during cataract surgery under local anaesthesia have received little attention until recently. This paper reviews the recent studies on this phenomenon, discusses its clinical significance and suggests novel approaches to reduce its negative impact on the surgery. Literature review. Many patients who have cataract surgery under retrobulbar, peribulbar or topical anaesthesia experience a variety of visual sensations in their operated eye during surgery. These visual sensations include perception of light, movements, flashes, one or more colours, surgical instruments, the surgeon's hand/fingers, the surgeon and changes in light brightness. Some patients experience transient no light perception, even if the operation is performed under topical anaesthesia. The clinical significance of this phenomenon lies in the fact that approximately 7.1% to 15.4% of patients find their visual experience frightening. This fear and anxiety may cause some patients to become uncooperative during surgery and trigger a sympathetic surge, causing such undesirable effects as hypertension, tachycardia, ischaemic strain on the heart, hyperventilation and acute panic attack. Several approaches to reduce the negative impact of patients' visual experience are suggested, including appropriate preoperative counselling and reducing the ability of patients to see during surgery. The findings that some patients find their intraoperative visual experience distressing have a major impact on the way ophthalmologists manage their cataract patients. To reduce its negative impact, surgeons should consider incorporating appropriate preoperative counselling on potential intraoperative visual experience when obtaining informed consent for surgery.

Cognitive training modifies frequency EEG bands and neuropsychological measures in Rett syndrome.

PubMed

Fabio, Rosa Angela; Billeci, Lucia; Crifaci, Giulia; Troise, Emilia; Tortorella, Gaetano; Pioggia, Giovanni

2016-01-01

Rett syndrome (RS) is a childhood neurodevelopmental disorder characterized by a primary disturbance in neuronal development. Neurological abnormalities in RS are reflected in several behavioral and cognitive impairments such as stereotypies, loss of speech and hand skills, gait apraxia, irregular breathing with hyperventilation while awake, and frequent seizures. Cognitive training can enhance both neuropsychological and neurophysiological parameters. The aim of this study was to investigate whether behaviors and brain activity were modified by training in RS. The modifications were assessed in two phases: (a) after a short-term training (STT) session, i.e., after 30 min of training and (b) after long-term training (LTT), i.e., after 5 days of training. Thirty-four girls with RS were divided into two groups: a training group (21 girls) who underwent the LTT and a control group (13 girls) that did not undergo LTT. The gaze and quantitative EEG (QEEG) data were recorded during the administration of the tasks. A gold-standard eye-tracker and a wearable EEG equipment were used. Results suggest that the participants in the STT task showed a habituation effect, decreased beta activity and increased right asymmetry. The participants in the LTT task looked faster and longer at the target, and show increased beta activity and decreased theta activity, while a leftward asymmetry was re-established. The overall result of this study indicates a positive effect of long-term cognitive training on brain and behavioral parameters in subject with RS. Copyright © 2016 Elsevier Ltd. All rights reserved.

Risk and prognostic factors of ventilator-associated pneumonia in trauma patients.

PubMed

Cavalcanti, Manuela; Ferrer, Miquel; Ferrer, Ricard; Morforte, Ramon; Garnacho, Angel; Torres, Antoni

2006-04-01

To assess the risk and prognostic factors of ventilator-associated pneumonia in trauma patients, with an emphasis on the inflammatory response. Case-control study. Trauma intensive care unit. Of 190 consecutive mechanically ventilated patients, those with microbiologically confirmed pneumonia (n = 62) were matched with 62 controls without pneumonia. None. Clinical, microbiological, and outcome variables were recorded. Cytokines were measured in serum and blind bronchoalveolar lavage specimens at onset of pneumonia. Multivariate analyses of risk and prognostic factors for ventilator-associated pneumonia were done. Increased severity of head and neck injury (odds ratio, 11.9; p < .001) was the only independent predictor of pneumonia. Among patients with pneumonia, serum levels of interleukin-6 (p = .019) and interleukin-8 (p = .036) at onset of pneumonia were higher in nonresponders to treatment. Moreover, serum levels of tumor necrosis factor-alpha (p = .028) and interleukin-6 (p = .007) at onset of pneumonia were higher in nonsurvivors. Mortality in the intensive care unit was 23% in cases and controls. Nonresponse to antimicrobial treatment (odds ratio, 22.2; p = .001) and the use of hyperventilation (p = .021) were independent predictors of mortality in the intensive care unit for patients with pneumonia. Severe head and neck trauma is strongly associated with ventilator-associated pneumonia. A higher inflammatory response is associated with nonresponse to treatment and mortality among patients with pneumonia. Although pneumonia did not influence mortality, nonresponse to treatment independently predicted mortality among these patients.

Global ischemia in dogs: cerebrovascular CO2 reactivity and autoregulation.

PubMed

Nemoto, E M; Snyder, J V; Carroll, R G; Morita, H

1975-01-01

One hypothesis on the pathogenesis of post-ischemic-anoxic encephalopathy is impaired cerebral perfusion or the no-reflow phenomenon. Therapies aimed at preventing the development of this phenomenon are increased cerebral perfusion pressure (CPP) and hyperventilation or hypercapnia. Using a dog model in which we have described the progressive development of post-ischemic (PI) cerebral hypoperfusion after 15 minutes of global ischemia induced by aortic and vena cavae clamping, our aims in this study were to determine during the PI cerebral hypoperfusion period: (1) cerebrovascular reactivity to CO2, and (2) cerebral blood (CBF) autoregulation. Post-ischemic cerebral hypoperfusion to about 50% of normal was not accompanied by raised intracranial pressure (ICP) but cerebrovascular CO2 reactivity was markedly attenuated while maintaining some kind of autoregulatory phenomenon. Cerebral uptake of oxygen was not significantly affected by changing PACO2 from 20 to 60 torr at constant CPP or by changing CPP from 64 to 104 torr at constant PaCO2. These results suggest that increasing both CPP and hypocapnia/hypercapnia would not significantly attenuate PI neurological deficit after global cerebral ischemia. However, in two dogs inadvertently hemodiluted in the PI period, increasing CPP from 50 to 200 torr increased CBF by 200%, suggesting that hemodilution plus increased CPP may be effective therapy for amelioration of post-ischemic-anoxic encephalopathy. The significance of our findings on cerebrovascular CO2 reactivity and autoregulation with respect to the mechanism of the no-reflow phenomenon is discussed.

PRM/NIR sensor for brain hematoma detection and oxygenation monitoring

NASA Astrophysics Data System (ADS)

Zheng, Liu; Lee, Hyo Sang; Lokos, Sandor; Kim, Jin; Hanley, Daniel F.; Wilson, David A.

1997-06-01

The pseudo-random modulation/near IR sensor (PRM/NIR Sensor) is a low cost portable system designed for time-resolved tissue diagnosis, especially hematoma detection in the emergency care facility. The sensor consists of a personal computer and a hardware unit enclosed in a box of size 37 X 37 X 31 cm3 and of weight less than 10 kg. Two pseudo-random modulated diode lasers emitting at 670 nm and 810 nm are used in the sensor as light sources. The sensor can be operated either in a single wavelength mode or a true differential mode. Optical fiber bundles are used for convenient light delivery and color filters are used to reject room light. Based on a proprietary resolution- enhancement correlation technique, the system achieves a time resolution better than 40 ps with a PRM modulation speed of 200 MHz and a sampling rate of 1-10 Gs/s. Using the prototype sensor, phantom experiments have been conducted to study the feasibility of the sensor. Brain's optical properties are simulated with solutions of intralipid and ink. Hematomas are simulated with bags of paint and hemoglobin immersed in the solution of varies sizes, depths, and orientations. Effects of human skull and hair are studied experimentally. In animal experiment, the sensor was used to monitor the cerebral oxygenation change due to hypercapnia, hypoxia, and hyperventilation. Good correlations were found between NIR measurement parameters and physiological changes induced to the animals.

Missing memories of death: Dissociative amnesia in the bereaved the day after a cancer death.

PubMed

Ishida, Mayumi; Onishi, Hideki; Toyama, Hiroaki; Tsutsumi, Chizuko; Endo, Chieko; Tanahashi, Iori; Takahashi, Takao; Uchitomi, Yosuke

2015-12-01

The death of a loved one is one of the most stressful events of life, and such stress affects the physical and psychological well-being of the bereaved. Dissociative amnesia is characterized by an inability to recall important autobiographical information. Dissociative amnesia in the bereaved who have lost a loved one to cancer has not been previously reported. We discuss herein the case of a patient who developed dissociative amnesia the day after the death of here beloved husband. A 38-year-old woman was referred for psychiatric consultation because of restlessness and abnormal behavior. Her 44-year-old husband had died of pancreatic cancer the day before the consultation. On the day of the death, she looked upset and began to hyperventilate. The next day, she behaved as if the deceased were still alive, which embarrassed her family. At her initial psychiatric consultation, she talked and behaved as if her husband was still alive and in the hospital. Her psychiatric features fulfilled the DSM-V criteria for dissociative amnesia. The death of her husband had been very traumatic for her and was considered to have been one of the causes of this dissociation. This report adds to the list of psychiatric symptoms in the bereaved who have lost a loved one to cancer. In an oncology setting, we should consider the impact of death, the concomitant defense mechanisms, and the background of the families.

Oxytocin's role on the cardiorespiratory activity of endotoxemic rats.

PubMed

Elorza-Ávila, Ana Rosa; Reyes-Lagos, José Javier; Hadamitzky, Martin; Peña-Castillo, Miguel Ángel; Echeverría, Juan Carlos; Ortiz-Pedroza, María Del Rocío; Lückemann, Laura; Schedlowski, Manfred; Pacheco-López, Gustavo

2017-02-01

Recent findings concerning oxytocin indicate its anti-inflammatory, cardioprotective and parasympathetic modulating properties. In this study, we investigated the effects of systemically applied oxytocin on the cardiorespiratory activity in a rodent model of moderate endotoxemia. Telemetrically recorded electrocardiogram (ECGs) from animals which received lipopolysaccharide (LPS); oxytocin (Ox); lipopolysaccharide+oxytocin (LPS+Ox), or vehicle (V) were analyzed using the ECG-derived respiration (EDR) technique to estimate the respiratory rate. The mean R-R interval and the spectral parameters of heart rate variability (HRV), such as the natural logarithm of the high frequency (lnHF) and low frequency (lnLF) components were also estimated up to 24h after treatment. The endotoxemic animals (LPS) showed an elevated respiratory rate as well as a reduced mean R-R interval, lnHF and lnLF components compared to controls (V) from +5 to +12h after the treatment. The administration of oxytocin significantly attenuated the hyperventilation produced by the LPS-induced endotoxemia (LPS+Ox) and restored the values of the mean R-R interval and such spectral parameters at different time points. Our results support the existence of a link among the respiratory, cardiovascular, and immune systems in which oxytocin seems to act as a potential cardioprotective peptide by favoring cardiac cholinergic autonomic coupling. As a result, oxytocin diminished animal's endotoxemic tachypnea and restored the cardiorespiratory interactions, which was indicated by the spectral components of HRV. Copyright © 2016 Elsevier B.V. All rights reserved.

High anion gap metabolic acidosis induced by cumulation of ketones, L- and D-lactate, 5-oxoproline and acute renal failure.

PubMed

Heireman, Laura; Mahieu, Boris; Helbert, Mark; Uyttenbroeck, Wim; Stroobants, Jan; Piqueur, Marian

2017-07-27

Frequent causes of high anion gap metabolic acidosis (HAGMA) are lactic acidosis, ketoacidosis and impaired renal function. In this case report, a HAGMA caused by ketones, L- and D-lactate, acute renal failure as well as 5-oxoproline is discussed. A 69-year-old woman was admitted to the emergency department with lowered consciousness, hyperventilation, diarrhoea and vomiting. The patient had suffered uncontrolled type 2 diabetes mellitus, underwent gastric bypass surgery in the past and was chronically treated with high doses of paracetamol and fosfomycin. Urosepsis was diagnosed, whilst laboratory analysis of serum bicarbonate concentration and calculation of the anion gap indicated a  HAGMA. L-lactate, D-lactate, β-hydroxybutyric acid, acetone and 5-oxoproline serum levels were markedly elevated and renal function was impaired. We concluded that this case of HAGMA was induced by a variety of underlying conditions: sepsis, hyperglycaemia, prior gastric bypass surgery, decreased renal perfusion and paracetamol intake. Risk factors for 5-oxoproline intoxication present in this case are female gender, sepsis, impaired renal function and uncontrolled type 2 diabetes mellitus. Furthermore, chronic antibiotic treatment with fosfomycin might have played a role in the increased production of 5-oxoproline. Paracetamol-induced 5-oxoproline intoxication should be considered as a cause of HAGMA in patients with female gender, sepsis, impaired renal function or uncontrolled type 2 diabetes mellitus, even when other more obvious causes of HAGMA such as lactate, ketones or renal failure can be identified.

TMS combined with EEG in genetic generalized epilepsy: A phase II diagnostic accuracy study.

PubMed

Kimiskidis, Vasilios K; Tsimpiris, Alkiviadis; Ryvlin, Philippe; Kalviainen, Reetta; Koutroumanidis, Michalis; Valentin, Antonio; Laskaris, Nikolaos; Kugiumtzis, Dimitris

2017-02-01

(A) To develop a TMS-EEG stimulation and data analysis protocol in genetic generalized epilepsy (GGE). (B) To investigate the diagnostic accuracy of TMS-EEG in GGE. Pilot experiments resulted in the development and optimization of a paired-pulse TMS-EEG protocol at rest, during hyperventilation (HV), and post-HV combined with multi-level data analysis. This protocol was applied in 11 controls (C) and 25 GGE patients (P), further dichotomized into responders to antiepileptic drugs (R, n=13) and non-responders (n-R, n=12).Features (n=57) extracted from TMS-EEG responses after multi-level analysis were given to a feature selection scheme and a Bayesian classifier, and the accuracy of assigning participants into the classes P-C and R-nR was computed. On the basis of the optimal feature subset, the cross-validated accuracy of TMS-EEG for the classification P-C was 0.86 at rest, 0.81 during HV and 0.92 at post-HV, whereas for R-nR the corresponding figures are 0.80, 0.78 and 0.65, respectively. Applying a fusion approach on all conditions resulted in an accuracy of 0.84 for the classification P-C and 0.76 for the classification R-nR. TMS-EEG can be used for diagnostic purposes and for assessing the response to antiepileptic drugs. TMS-EEG holds significant diagnostic potential in GGE. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Influence of ventilation and hypocapnia on sympathetic nerve responses to hypoxia in normal humans.

PubMed

Somers, V K; Mark, A L; Zavala, D C; Abboud, F M

1989-11-01

The sympathetic response to hypoxia depends on the interaction between chemoreceptor stimulation (CRS) and the associated hyperventilation. We studied this interaction by measuring sympathetic nerve activity (SNA) to muscle in 13 normal subjects, while breathing room air, 14% O2, 10% O2, and 10% O2 with added CO2 to maintain isocapnia. Minute ventilation (VE) and blood pressure (BP) increased significantly more during isocapnic hypoxia (IHO) than hypocapnic hypoxia (HHO). In contrast, SNA increased more during HHO [40 +/- 10% (SE)] than during IHO (25 +/- 19%, P less than 0.05). To determine the reason for the lesser increase in SNA with IHO, 11 subjects underwent voluntary apnea during HHO and IHO. Apnea potentiated the SNA responses to IHO more than to HHO. SNA responses to IHO were 17 +/- 7% during breathing and 173 +/- 47% during apnea whereas SNA responses to HHO were 35 +/- 8% during breathing and 126 +/- 28% during apnea. During ventilation, the sympathoexcitation of IHO (compared with HHO) is suppressed, possibly for two reasons: 1) because of the inhibitory influence of activation of pulmonary afferents as a result of a greater increase in VE, and 2) because of the inhibitory influence of baroreceptor activation due to a greater rise in BP. Thus in humans, the ventilatory response to chemoreceptor stimulation predominates and restrains the sympathetic response. The SNA response to chemoreceptor stimulation represents the net effect of the excitatory influence of the chemoreflex and the inhibitory influence of pulmonary afferents and baroreceptor afferents.

Gestation increases the energetic cost of breathing in the lizard Tiliqua rugosa.

PubMed

Munns, Suzanne L

2013-01-15

High gestational loads result in fetuses that occupy a large proportion of the body cavity and may compress maternal organs. Compression of the lungs results in alterations in breathing patterns during gestation, which may affect the energetic cost of breathing. In this study, the energetic cost of breathing during gestation was determined in the viviparous skink Tiliqua rugosa. Radiographic imaging showed progressive lung compression during gestation and a 30% reduction in the lung inflation index (rib number at which the caudal margin of the lung was imaged divided by total rib number). Pneumotachography and open flow respirometry were used to measure breathing patterns and metabolic rates. Gestation induced a twofold increase in minute ventilation via increases in breathing frequency, but no change in inspired tidal volume. The rates of O(2) consumption and CO(2) production did not change significantly during gestation. Together, these results suggest that a relative hyperventilation occurs during gestation in T. rugosa, which in turn suggests that diffusion and/or perfusion limitations may exist at the lung during gestation. The energetic cost of breathing was estimated as a percentage of resting metabolic rate using hypercapnia to stimulate ventilation at different stages of pregnancy. The energetic cost of breathing in non-pregnant lizards was 19.96±3.85% of resting metabolic rate and increased threefold to 62.80±10.11% during late gestation. This significant increase in the energetic cost of breathing may have significant consequences for energy budgets during gestation.

Comparison of cerebral vascular reactivity measures obtained using breath-holding and CO2 inhalation

PubMed Central

Tancredi, Felipe B; Hoge, Richard D

2013-01-01

Stimulation of cerebral vasculature using hypercapnia has been widely used to study cerebral vascular reactivity (CVR), which can be expressed as the quantitative change in cerebral blood flow (CBF) per mm Hg change in end-tidal partial pressure of CO2 (PETCO2). We investigate whether different respiratory manipulations, with arterial spin labeling used to measure CBF, lead to consistent measures of CVR. The approaches included: (1) an automated system delivering variable concentrations of inspired CO2 for prospective targeting of PETCO2, (2) administration of a fixed concentration of CO2 leading to subject-dependent changes in PETCO2, (3) a breath-hold (BH) paradigm with physiologic modeling of CO2 accumulation, and (4) a maneuver combining breath-hold and hyperventilation. When CVR was expressed as the percent change in CBF per mm Hg change in PETCO2, methods 1 to 3 gave consistent results. The CVR values using method 4 were significantly lower. When CVR was expressed in terms of the absolute change in CBF (mL/100 g per minute per mm Hg), greater discrepancies became apparent: methods 2 and 3 gave lower absolute CVR values compared with method 1, and the value obtained with method 4 was dramatically lower. Our findings indicate that care must be taken to ensure that CVR is measured over the linear range of the CBF-CO2 dose–response curve, avoiding hypocapnic conditions. PMID:23571282

Camera-based measurement of respiratory rates is reliable.

PubMed

Becker, Christoph; Achermann, Stefan; Rocque, Mukul; Kirenko, Ihor; Schlack, Andreas; Dreher-Hummel, Thomas; Zumbrunn, Thomas; Bingisser, Roland; Nickel, Christian H

2017-06-01

Respiratory rate (RR) is one of the most important vital signs used to detect whether a patient is in critical condition. It is part of many risk scores and its measurement is essential for triage of patients in emergency departments. It is often not recorded as measurement is cumbersome and time-consuming. We intended to evaluate the accuracy of camera-based measurements as an alternative measurement to the current practice of manual counting. We monitored the RR of healthy male volunteers with a camera-based prototype application and simultaneously by manual counting and by capnography, which was considered the gold standard. The four assessors were mutually blinded. We simulated normoventilation, hypoventilation and hyperventilation as well as deep, normal and superficial breathing depths to assess potential clinical settings. The volunteers were assessed while being undressed, wearing a T-shirt or a winter coat. In total, 20 volunteers were included. The results of camera-based measurements of RRs and capnography were in close agreement throughout all clothing styles and respiratory patterns (Pearson's correlation coefficient, r=0.90-1.00, except for one scenario, in which the volunteer breathed slowly dressed in a winter coat r=0.84). In the winter-coat scenarios, the camera-based prototype application was superior to human counters. In our pilot study, we found that camera-based measurements delivered accurate and reliable results. Future studies need to show that camera-based measurements are a secure alternative for measuring RRs in clinical settings as well.

[A man with a classic serious milk-alkali syndrome and a carcinoma of the stomach].

PubMed

Verburg, F A J; van Zanten, R A A; Brouwer, R M L; Woittiez, A J J; Veneman, Th F

2006-07-22

A 42-year-old man was transferred to the Emergency Department after his friends had found him unresponsive and confused in his room. He had been experiencing upper abdominal complaints for a period of several months. He had taken large amounts of a calcium carbonate/magnesium subcarbonate preparation (Rennie) and had consumed at least 3 litres of dairy products per day. His behaviour was reported as being more and more abnormal during the previous few weeks. On admission he was confused and agitated and had involuntary movements of his limbs. Laboratory investigation indicated a triple acid base disorder, i.e. metabolic alkalosis, respiratory alkalosis and high anion gap metabolic acidosis, with severe dehydration. The metabolic alkalosis was caused by the intake of large amounts of dairy and antacids: milk-alkali syndrome. The metabolic acidosis was the result of hypovolaemia and pre-renal renal failure and the respiratory alkalosis was caused by hyperventilation due to the organic psychosyndrome. The patient was treated with volume expansion by isotonic saline and the administration of potassium and he was sedated with low-dose midazolam, which led to a full respiratory compensation of the metabolic alkalosis. A few days following admission, both the plasma calcium concentration and renal function returned to normal; the acid-base disorder completely normalized and the organic psychosyndrome disappeared. On gastroduodenoscopy a gastric ulcer was found; biopsies revealed a signet ring cell adenocarcinoma of the stomach.

Prevention of needless deaths from drowning.

PubMed

Modell, Jerome H

2010-07-01

To determine whether faulty pool maintenance and substandard lifeguard performance critically delayed retrieval and resuscitation of a significant number of pool drowning victims. One hundred and eighty drowning incidents that resulted in litigation from 1998 to 2008 were studied to determine whether faulty pool maintenance and/or substandard lifeguard performance delayed retrieval and thereby contributed to the death of these persons. A total of 180 swimming pools-commercial and private-were included. Ninety-seven of these pools were manned by lifeguards. Subjects who underwent the drowning process and suffered severe brain injury or death were reviewed to determine the rescue and resuscitation attempts by lifeguards or bystanders at the pool. One hundred and seventy-seven of the 180 persons who underwent the drowning process died. Cases were analyzed as to whether faulty pool maintenance and/or substandard lifeguard performance contributed to their demise. At fault were cloudy or dirty water; drain pipes that created underwater suction to trap victims; inadequate fencing around pools through which small children gained access; permitting small children to be at the pool without adult supervision; permitting dangerous exercises such as hyperventilation while underwater swimming, resulting in shallow water blackout; lifeguards not being attentive, being distracted by other persons, performing nonrelated chores, leaving their positions without proper relief, while failure to enter the water when told persons were submerged. Faculty pool maintenance and substandard lifeguard performance critically delayed retrieval and resuscitation of a significant number of pool drowning victims.

Some unexplored regions of psychosomatic medicine.

PubMed

Weiner, H

1987-01-01

The history of psychosomatic medicine in the 20th century is predominantly marked by a concern with studies of major diseases (e.g., angina pectoris, bronchial asthma, diabetes mellitus, essential hypertension, neurodermatitis, rheumatoid arthritis, etc.). Traditional physicians also narrowly focus on disease--a trend that began with Morgagni in the 18th century. But disease (defined by structural alterations) is not the only cause of illness and disability. In fact, most persons seeking health care are ill without having a disease. It is only recently that this distinction has been fully made. The various manifestations of ill-health go by a variety of descriptive names--the functional or irritable bowel and hyperventilation syndromes, fibromyositis, psychophysiological, functional and somatoform or somatization disorders. They lead to loss of productivity, cost the health care system excessively, produce negative reactions in physicians, and are fertile ground for iatrogenic disease. They do not constitute discrete syndromes but overlap, each also being closely associated with anxiety and depression, sleep disturbances or marital disruption. They are the manifestations of sick persons not only of disturbances of bodily systems. They may be precipitated by unemployment, marital discord, bereavement, and job dissatisfaction. Curiously, ill-health has not been the major area of investigative interest of psychosomatic medicine. This presentation will emphasize why it should be, and why proper interventions may radically reduce the cost of medical care, prevent iatrogenic disease, and reduce the use of ill-advised procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Placebo-controlled crossover assessment of mecasermin for the treatment of Rett syndrome.

PubMed

O'Leary, Heather M; Kaufmann, Walter E; Barnes, Katherine V; Rakesh, Kshitiz; Kapur, Kush; Tarquinio, Daniel C; Cantwell, Nicole G; Roche, Katherine J; Rose, Suzanne A; Walco, Alexandra C; Bruck, Natalie M; Bazin, Grace A; Holm, Ingrid A; Alexander, Mark E; Swanson, Lindsay C; Baczewski, Lauren M; Mayor Torres, Juan M; Nelson, Charles A; Sahin, Mustafa

2018-03-01

To measure the efficacy of mecasermin (recombinant human insulin-like growth factor 1, rhIGF-1), for treating symptoms of Rett syndrome (RTT) in a pediatric population using a double-blind crossover study design. Thirty girls with classic RTT in postregression stage were randomly assigned to placebo or rhIGF-1 in treatment period 1 and crossed over to the opposite assignment for period 2 (both 20 weeks), separated by a 28-week washout period. The primary endpoints were as follows: Anxiety Depression and Mood Scale (ADAMS) Social Avoidance subscale, Rett Syndrome Behaviour Questionnaire (RSBQ) Fear/Anxiety subscale, Parent Target Symptom Visual Analog Scale (PTSVAS) top three concerns, Clinical Global Impression (CGI), Parent Global Impression (PGI), and the Kerr severity scale. Cardiorespiratory- and electroencephalography (EEG)-based biomarkers were also analyzed. There were no significant differences between randomization groups. The majority of AEs were mild to moderate, although 12 episodes of serious AEs occurred. The Kerr severity scale, ADAMS Depressed Mood subscale, Visual Analog Scale Hyperventilation, and delta average power change scores significantly increased, implying worsening of symptoms. Electroencephalography (EEG) parameters also deteriorated. A secondary analysis of subjects who were not involved in a placebo recall confirmed most of these findings. However, it also revealed improvements on a measure of stereotypic behavior and another of social communication. As in the phase 1 trial, rhIGF-1 was safe; however, the drug did not reveal significant improvement, and some parameters worsened.

How to take arms against central apneas in heart failure.

PubMed

Borrelli, Chiara; Aimo, Alberto; Mirizzi, Gianluca; Passino, Claudio; Vergaro, Giuseppe; Emdin, Michele; Giannoni, Alberto

2017-10-01

Introduction Despite being a risk mediator in several observational studies, central apneas are currently orphan of treatment in heart failure. After the neutral effects on survival of two randomized controlled trials (RCTs) based on the use of positive airway pressure (the CANPAP and SERVE-HF trials), two alternative hypotheses have been formulated: 1) Periodic breathing/Cheyne-Stokes respiration (PB/CSR) in HF is protective. Indeed, the Naughton's hypothesis assumes that hyperventilation leads to increased cardiac output, lung volume, oxygen storage and reduced muscle sympathetic nerve activity, while central apnea to respiratory muscle rest and hypoxia-induced erythropoiesis. 2) The use of positive airway pressure is just a wrong treatment for PB/CSR. If this is the case, the search for novel potential alternative treatment approaches is mandatory in HF. Areas covered This review will focus on the crucial issue of whether PB/CSR should be treated or not in HF, first by outlining the ideal design of pathophysiological studies to test the Naughton's hypothesis and second by summarizing the treatment strategies so far proposed for PB/CSR in HF and identifying the most promising options to be tested in future RCTs. Expert commentary It is likely that PB/CSR may be compensatory in some cases, but after a certain threshold (to be defined) it becomes maladaptive with negative prognostic meaning in HF. The development of a pathophysiologically based treatment targeting feedback resetting and neurohormonal activation underlying PB/CSR is likely to be the best option to obtain survival benefits in HF.

Adenosine A2a receptors and O2 sensing in development

PubMed Central

2011-01-01

Reduced mitochondrial oxidative phosphorylation, via activation of adenylate kinase and the resulting exponential rise in the cellular AMP/ATP ratio, appears to be a critical factor underlying O2 sensing in many chemoreceptive tissues in mammals. The elevated AMP/ATP ratio, in turn, activates key enzymes that are involved in physiologic adjustments that tend to balance ATP supply and demand. An example is the conversion of AMP to adenosine via 5′-nucleotidase and the resulting activation of adenosine A2A receptors, which are involved in acute oxygen sensing by both carotid bodies and the brain. In fetal sheep, A2A receptors associated with carotid bodies trigger hypoxic cardiovascular chemoreflexes, while central A2A receptors mediate hypoxic inhibition of breathing and rapid eye movements. A2A receptors are also involved in hypoxic regulation of fetal endocrine systems, metabolism, and vascular tone. In developing lambs, A2A receptors play virtually no role in O2 sensing by the carotid bodies, but brain A2A receptors remain critically involved in the roll-off ventilatory response to hypoxia. In adult mammals, A2A receptors have been implicated in O2 sensing by carotid glomus cells, while central A2A receptors likely blunt hypoxic hyperventilation. In conclusion, A2A receptors are crucially involved in the transduction mechanisms of O2 sensing in fetal carotid bodies and brains. Postnatally, central A2A receptors remain key mediators of hypoxic respiratory depression, but they are less critical for O2 sensing in carotid chemoreceptors, particularly in developing lambs. PMID:21677265

Neurologic decompression sickness following cabin pressure fluctuations at high altitude.

PubMed

Auten, Jonathan D; Kuhne, Michael A; Walker, Harlan M; Porter, Henry O

2010-04-01

Decompression sickness (DCS) occurs in diving, altitude chamber exposures, and unpressurized or depressurized high-altitude flights. Because DCS takes many forms, in-flight cases may be misinterpreted as hypoxia, hyperventilation, or viral illness, with resulting failure to respond appropriately. In this case, a 28-yr-old male pilot of a single-seat, tactical aircraft experienced 12 rapid pressure fluctuations while flying at 43,000 ft above sea level. He had no symptoms and decided to complete the flight, which required an additional 2 h in the air. Approximately 1 h later he began to experience fatigue, lightheadedness, and confusion, which he interpreted as onset of a viral illness. However, symptoms progressed to visual, cognitive, motor, and sensory degradations and it was with some difficulty that he landed safely at his destination. Neurologic DCS was suspected on initial evaluation by flight line medical personnel because of the delayed onset and symptom progression. He was transferred to a local Emergency Department and noted to have altered mental status, asymmetric motor deficits, and non-dermatomal paresthesias of the upper and lower extremities. Approximately 3.5 h after the incident and 2.5 h after the onset of symptoms he began hyperbaric oxygen therapy. He received partial relief at 30 min of the Navy DiveTable 6 and full resolution at 90 min; there were no recurrent symptoms at a 1-yr follow-up. This case highlights the importance of early recognition of in-flight DCS symptoms and landing as soon as possible rather than as soon as practical in all likely scenarios.

Altitude-related hypoxia: risk assessment and management for passengers on commerical aircraft.

PubMed

Mortazavi, Amir; Eisenberg, Mark J; Langleben, David; Ernst, Pierre; Schiff, Renee L

2003-09-01

Individuals with pulmonary and cardiac disorders are particularly at risk of developing hypoxemia at altitude. Our objective is to describe the normal and maladaptive physiological responses to altitude-related hypoxia, to review existing methods and guidelines for preflight assessment of air travelers, and to provide recommendations for treatment of hypoxia at altitude. Falling partial pressure of oxygen with altitude results in a number of physiologic adaptations including hyperventilation, pulmonary vasoconstriction, altered ventilation/perfusion matching, and increased sympathetic tone. According to three guideline statements, the arterial pressure of oxygen (PaO2) should be maintained above 50 to 55 mm Hg at all altitudes. General indicators such as oxygen saturation and sea level blood gases may be useful in predicting altitude hypoxia. More specialized techniques for estimation of altitude PaO2, such as regression equations, hypoxia challenge testing, and hypobaric chamber exposure have also been examined. A regression equation using sea level PaO2 and spirometric parameters can be used to estimate PaO2 at altitude. Hypoxia challenge testing, performed by exposing subjects to lower inspired FIO2 at sea level may be more precise. Hypobaric chamber exposure, the gold standard, mimics lower barometric pressure, but is mainly used in research. Oxygen supplementation during air travel is needed for individuals with an estimated PaO2 (8000 ft) below 50 mmHg. There are a number of guidelines for the pre-flight assessment of patients with pulmonary and/or cardiac diseases. However, these data are based on small studies in patients with a limited group of diseases.

Ventilation by high-frequency chest wall compression in dogs with normal lungs.

PubMed

Zidulka, A; Gross, D; Minami, H; Vartian, V; Chang, H K

1983-06-01

In 6 anesthetized and paralyzed supine dogs, ventilation by high-frequency chest wall compression (HFCWC) was accomplished by a piston pump rapidly oscillating the pressure in a modified double blood pressure cuff wrapped around the lower thorax. Testing applied frequencies at 3, 5, 8, and 11 Hz, applied peak cuff pressures ranged from 30 to 230 cmH2O. This produced swings of esophageal pressure as high as 18 cmH2O and peak oscillatory air flow ranging from 0.7 to 1.6 L/s. Oscillatory tidal volume declined with increasing frequency and ranged from a mean of 61 to 45 ml. After 30 min of applied HFCWC, arterial blood gas determinations revealed a mean PaCO2 of 29.3 mmHg at 5 Hz, 35 mmHg at 3 Hz, 36 mmHg at 8 Hz, and 51 mmHg at 11 Hz. Mean PaO2 improved from ventilator control values at 3 Hz, remained unchanged at 5 and 8 Hz, and declined at 11 Hz. In 2 dogs breathing spontaneously, HFCWC applied at 5 and 11 Hz resulted in a reduction in spontaneous minute ventilation, mainly by a reduction in spontaneous tidal volume, whereas arterial blood gas values changed slightly. One dog ceased to breath spontaneously within 5 min of application of HFCWC as the PaCO2 fell below control values. We conclude that in dogs with normal lungs, HFCWC may assist spontaneous ventilation. In paralyzed dogs, HFCWC may be of sufficient magnitude to cause hyperventilation.

Impact of alignment to gravito-inertial force on motion sickness and cardiopulmonary variables.

PubMed

Mert, Agali; Bles, Willem

2011-07-01

In tilting trains partial alignment to the gravito-inertial force (GIF) in the curves seems to be the best tilt compensation to reduce the incidence of motion sickness. We investigated the effect of alignment to the GIF on the development of motion sickness during low-frequency horizontal motion. There were 12 healthy subjects who participated. The design was a three-period, single-blind, crossover trial, counterbalanced for order. Cardiopulmonary measurements, Misery SCores (MISC), and questionnaire data (Motion Sickness Susceptibility Questionnaire, Nijmegen Questionnaire for Hyperventilation) were obtained. The stimulus was a sinusoidal movement (0.176 Hz, 0.2 g peak acceleration) on the ESA-sled. The cabin was compensated for 0% (A-0), 50% (A-50), and 100% (A-100) to the GIF. Runs were 1 wk apart. The A-50 condition may delay the development of motion sickness. Based on the survival curves the possible effect seems temporary. However, MISC 2 early in the runs resulted in high positive and negative predictive values for dropout and survival during the runs. No synchronization of the respiratory frequency with the sled motion was observed. There was a significant (P = 0.002) drop in relative end-tidal CO2 levels. There seems to be a rationale for partially compensating to the GIF while trying to prevent motion sickness in tilting trains. Sitting comfort is just better than without compensation at all and Coriolis effects are not as nauseating as with complete tilt compensation. Also, a drop in end-tidal CO2 levels might be a sign of pulmonary compensation for the nauseating stimulus.

Therapeutical options for the treatment of Cheyne-Stokes respiration.

PubMed

Randerath, Winfried J

2009-03-07

The awareness of Cheyne-Stokes respiration (CSR) and of the co-existence of the obstructive sleep apnoea syndrome and central breathing disturbances has rapidly grown in recent years. CSR is defined by a waxing and waning pattern of the breathing amplitude. Sleep related breathing disorders in patients with heart failure are associated with impaired clinical outcome and survival. While continuous positive airway pressure treatment (CPAP) is widely used to treat CSR, it has failed to improve overall survival of heart failure patients. Nevertheless, it has been shown that CPAP reduces mortality if breathing disturbances were sufficiently eliminated. Therefore, optimal suppression of CSR is critical. While CPAP reduces CSR by 50% on average, adaptive servoventilation (ASV) normalises CSR in most patients. ASV devices apply different levels of pressure support: during periods of hypoventilation the inspiratory pressure is increased while it is reduced to the lowest possible level during hyperventilation. The devices deliver an expiratory pressure to overcome upper airways obstruction. Pressure support is defined by the difference between expiratory and inspiratory pressure. Thus, while pressure support is fixed in bilevel devices, it varies under ASV. However, the hypothesis that ASV might improve survival in CSR patients has to be proved in prospective studies in CPAP nonresponders. There is a lack of evidence on the use of bilevel devices in CSR. However, ASV has proven both to effectively treat CSR and to be superior to CPAP in respiratory and sleep parameters in short term and medium term studies. Nevertheless, data on the long term use and the influence on cardiac parameters are necessary.

Stimulation of abdominal and upper thoracic muscles with surface electrodes for respiration and cough: Acute studies in adult canines.

PubMed

Walter, James S; Posluszny, Joseph; Dieter, Raymond; Dieter, Robert S; Sayers, Scott; Iamsakul, Kiratipath; Staunton, Christine; Thomas, Donald; Rabbat, Mark; Singh, Sanjay

2018-05-01

To optimize maximal respiratory responses with surface stimulation over abdominal and upper thorax muscles and using a 12-Channel Neuroprosthetic Platform. Following instrumentation, six anesthetized adult canines were hyperventilated sufficiently to produce respiratory apnea. Six abdominal tests optimized electrode arrangements and stimulation parameters using bipolar sets of 4.5 cm square electrodes. Tests in the upper thorax optimized electrode locations, and forelimb moment was limited to slight-to-moderate. During combined muscle stimulation tests, the upper thoracic was followed immediately by abdominal stimulation. Finally, a model of glottal closure for cough was conducted with the goal of increased peak expiratory flow. Optimized stimulation of abdominal muscles included three sets of bilateral surface electrodes located 4.5 cm dorsal to the lateral line and from the 8 th intercostal space to caudal to the 13 th rib, 80 or 100 mA current, and 50 Hz stimulation frequency. The maximal expired volume was 343 ± 23 ml (n=3). Optimized upper thorax stimulation included a single bilateral set of electrodes located over the 2 nd interspace, 60 to 80 mA, and 50 Hz. The maximal inspired volume was 304 ± 54 ml (n=4). Sequential stimulation of the two muscles increased the volume to 600 ± 152 ml (n=2), and the glottal closure maneuver increased the flow. Studies in an adult canine model identified optimal surface stimulation methods for upper thorax and abdominal muscles to induce sufficient volumes for ventilation and cough. Further study with this neuroprosthetic platform is warranted.

[Blood coagulation and fibrinolysis in ischemic heart disease].

PubMed

Sakamoto, T; Ogawa, H; Miyao, Y; Yasue, H

1994-01-01

Intracoronary thrombus formation has been thought to play an important role in the genesis of acute myocardial infarction an unstable angina. To examine whether the coagulation and fibrinolytic systems are altered in such ischemic heart diseases, the plasma levels of fibrinopeptide A (FPA) and plasminogen activator (PAI) were measured. The plasma level of FPA was increased in patients with variant angina as compared with those with stable exertional angina and there was a significant circadian variation in the plasma level of FPA in parallel with that of the frequency of the attacks with the peak level occurring from midnight to early morning in patients with variant angina. The plasma FPA level increased in patients with coronary spastic angina after the ischemic attack induced by hyperventilation. Furthermore, FPA was released into the coronary circulation after the anginal attack induced by intracoronary injection of acetylcholine. These findings suggest that the coronary artery spasm may induce thrombin generation and trigger thrombus formation in the coronary artery. On the other hand, the plasma level of PAI activity was higher in patients with unstable angina and coronary spastic angina than in those with stable exertional angina. Moreover, the PAI activity in patients with unstable angina decreased to the level in patients with stable exertional angina after the stabilization of their symptoms by drugs. Our findings suggest that the increased plasma PAI activity may reduce fibrinolytic activity and attenuate removal of the thrombus and may ultimately lead to acute myocardial infarction in some patients with unstable angina and coronary spastic angina.(ABSTRACT TRUNCATED AT 250 WORDS)

The contribution(s) of the insula to speech production: a review of the clinical and functional imaging literature.

PubMed

Ackermann, Hermann; Riecker, Axel

2010-06-01

Skilled spoken language production requires fast and accurate coordination of up to 100 muscles. A long-standing concept--tracing ultimately back to Paul Broca--assumes posterior parts of the inferior frontal gyrus to support the orchestration of the respective movement sequences prior to innervation of the vocal tract. At variance with this tradition, the insula has more recently been declared the relevant "region for coordinating speech articulation", based upon clinico-neuroradiological correlation studies. However, these findings have been criticized on methodological grounds. A survey of the clinical literature (cerebrovascular disorders, brain tumours, stimulation mapping) yields a still inconclusive picture. By contrast, functional imaging studies report more consistently hemodynamic insular responses in association with motor aspects of spoken language. Most noteworthy, a relatively small area at the junction of insular and opercular cortex was found sensitive to the phonetic-linguistic structure of verbal utterances, a strong argument for its engagement in articulatory control processes. Nevertheless, intrasylvian hemodynamic activation does not appear restricted to articulatory processes and might also be engaged in the adjustment of the autonomic system to ventilatory needs during speech production: Whereas the posterior insula could be involved in the cortical representation of respiration-related metabolic (interoceptive) states, the more rostral components, acting upon autonomic functions, might serve as a corollary pathway to "voluntary control of breathing" bound to corticospinal and -bulbar fiber tracts. For example, the insula could participate in the implementation of task-specific autonomic settings such as the maintenance of a state of relative hyperventilation during speech production.

Studies on the Nature and Aetiology of Respiratory Disability in Witwatersrand Gold-Miners Free of Radiological Silicosis

PubMed Central

Becklake, Margaret R.; Zwi, Saul; Lutz, W.

1959-01-01

In an investigation into the cause of symptoms in gold-miners who have no radiological silicosis, the relationship of dyspnoea and physiological disturbances to dust exposure was examined. Forty-five subjects, aged 41 to 45 years, with normal chest radiographs and long service underground were chosen for study from the population of miners past and present. Thirty-four men only were tested, but the validity of the sample was checked by comparison with a similar group of miners reported previously. Each individual's dust exposure was estimated in “particle-hours”. A detailed history, including smoking habits, was followed by a clinical examination and a battery of lung function tests in each case. No significant relationship was found between dyspnoea and dust exposure or smoking. However, a negative correlation was observed between dust exposure and effort tests, implying that exercise capacity appeared best in those men whose dust exposure was greatest. Possible reasons for this finding are discussed. On the other hand, dyspnoea did correlate with airway obstruction and hyperventilation on effort, indicating a physiological rather than a psychological basis for the symptoms. Further, the higher incidence of cough, sputum, and rhonchi in the more disabled subjects suggested that chronic bronchitis might be the basis of their symptoms, but the cause of the bronchitis remains to be identified. It seems that dust exposure alone was not the cause, but the findings do not exclude the possibility of its being related to the occupation of mining with stresses such as inhalation of fumes and rapid changes in temperature, humidity, and altitude. PMID:13798146

Effects of salinity and hypoxia-induced hyperventilation on oxygen consumption and cost of osmoregulation in the estuarine red drum (Sciaenops ocellatus).

PubMed

Ern, Rasmus; Esbaugh, Andrew J

2018-04-23

Understanding the physiological responses of fishes to salinity changes and aquatic hypoxia is essential for the conservation of marine species. Salinity changes affect the osmotic gradient across the gill epithelium, while hypoxia increases gill ventilation and the flow of water over the gills. Both processes affect the diffusive movement of ions and water across the gill epithelium, and the rate of active ion transport required for maintaining osmotic homeostasis. Consequently, salinity and hypoxia may affect the energetic cost of osmoregulation, and consequently the energy available for other physiological functions such as migration, growth, and reproduction. Historically, studies have assessed the costs of osmoregulation and ventilation in fishes via standard metabolic rate (SMR); however, few studies have used a multi-stressor approach that fully accounts for the osmorespiratory compromise. Here, we determined the combined effects of salinity and hypoxia on SMR, routine metabolic rate (RMR), and plasma ion concentrations in red drum (Sciaenops ocellatus) acclimated to salinities ranging from freshwater to hypersalinity. Surprisingly, there was no significant change in any parameter as a consequence of salinity or hypoxia, including the relatively extreme scenario of combined hypersalinity and hypoxia exposure. We conclude that changes in the osmotic gradient across the gill epithelium and the flow of water over the gills have a negligible effect on the whole animal energy budget of S. ocellatus, suggesting that the cost of osmoregulation is a minor component of basal metabolism regardless of oxygenation status. Copyright © 2018 Elsevier Inc. All rights reserved.

Carotid body, insulin, and metabolic diseases: unraveling the links

PubMed Central

Conde, Sílvia V.; Sacramento, Joana F.; Guarino, Maria P.; Gonzalez, Constancio; Obeso, Ana; Diogo, Lucilia N.; Monteiro, Emilia C.; Ribeiro, Maria J.

2014-01-01

The carotid bodies (CB) are peripheral chemoreceptors that sense changes in arterial blood O2, CO2, and pH levels. Hypoxia, hypercapnia, and acidosis activate the CB, which respond by increasing the action potential frequency in their sensory nerve, the carotid sinus nerve (CSN). CSN activity is integrated in the brain stem to induce a panoply of cardiorespiratory reflexes aimed, primarily, to normalize the altered blood gases, via hyperventilation, and to regulate blood pressure and cardiac performance, via sympathetic nervous system (SNS) activation. Besides its role in the cardiorespiratory control the CB has been proposed as a metabolic sensor implicated in the control of energy homeostasis and, more recently, in the regulation of whole body insulin sensitivity. Hypercaloric diets cause CB overactivation in rats, which seems to be at the origin of the development of insulin resistance and hypertension, core features of metabolic syndrome and type 2 diabetes. Consistent with this notion, CB sensory denervation prevents metabolic and hemodynamic alterations in hypercaloric feed animal. Obstructive sleep apnea (OSA) is another chronic disorder characterized by increased CB activity and intimately related with several metabolic and cardiovascular abnormalities. In this manuscript we review in a concise manner the putative pathways linking CB chemoreceptors deregulation with the pathogenesis of insulin resistance and arterial hypertension. Also, the link between chronic intermittent hypoxia (CIH) and insulin resistance is discussed. Then, a final section is devoted to debate strategies to reduce CB activity and its use for prevention and therapeutics of metabolic diseases with an emphasis on new exciting research in the modulation of bioelectronic signals, likely to be central in the future. PMID:25400585

Cardiorespiratory screening in elite endurance sports athletes: the Quebec study.

PubMed

Turmel, Julie; Poirier, Paul; Bougault, Valérie; Blouin, Evelyne; Belzile, Mireille; Boulet, Louis-Philippe

2012-09-01

Cardiorespiratory disorders are common in athletes. However, these conditions are often underdiagnosed, which potentially results in impaired performance and increased health risks. The aim of this study was to evaluate, in a research setting, the prevalence of cardiorespiratory disorders in athletes in order to determine the potential value of a screening program. One hundred thirty-three athletes were studied. Each subject underwent a physical examination. A eucapnic voluntary hyperventilation (EVH) test and a methacholine inhalation test were performed to confirm the diagnosis of asthma. A cardiovascular evaluation was also performed, including maximal exercise test with electrocardiogram, 24-hour ambulatory blood pressure monitoring, 24-hour Holter monitoring, and blood sampling. Seventy-four (56%) athletes had airway hyperresponsiveness to EVH or the methacholine inhalation test. Among those with airway hyperresponsiveness, 45 (61%) athletes were only hyperresponsive to EVH, and 10 (14%) were only hyperresponsive to the methacholine inhalation test (using the criteria of a PC20 ≤ 4 mg/mL). Thirty-two (24%) athletes had a known diagnosis of asthma, while 34 (26%) athletes received a new asthma diagnosis. Ninety-seven (73%) athletes were sensitized to common airborne allergens. Forty-seven (35%) athletes completed the cardiovascular evaluation. Three (6%) and 7 (15%) athletes had a previous or new diagnosis of cardiovascular disease, respectively. Resting systemic hypertension was documented in 2 (4%) athletes and exaggerated blood pressure response to exercise was found in 12 (26%) athletes. This cardiorespiratory screening data set in athletes showed a high prevalence of exercise-induced asthma and exercise hypertension, which in many cases were not previously diagnosed.

Cardiopulmonary changes during clarinet playing.

PubMed

Hahnengress, Maria L; Böning, Dieter

2010-12-01

Since playing wind instrument impedes normal respiratory functions, its effect on expiratory and blood gases as well as on cardiac function was investigated. In 15 skilled clarinettists expiratory PO(2) and PCO(2) were measured in gas drawn from a modified clarinet barrel when playing a composition (Robert Schumann's "Phantasiestücke" Op. 73 for clarinet and piano) with increasing difficulty from movement 1 to movement 3. Blood gases were measured in arterialized ear lobe blood at the end of each movement and the electrocardiogram was recorded continuously. From the expiratory gas pressures one may conclude that the most advanced players adapt their ventilation to the requirements of the composition and sustain expiration during difficult parts of the composition until hypoxic alveolar PO(2) values are reached (minimum 77 mmHg). Less trained clarinettists tend to hyperventilation or shallow breathing. Oxygen saturation in arterialized blood showed a slight step-wise decrease from movement to movement [control 96.6 ± 0.5 (SD)%, end of concert 95.6 ± 1.0%]. SO(2) was significantly higher because of possibly more effective ventilation in instrumentalists with practise time exceeding 2 h daily. Mean heart rate increased to values like during moderate to heavy physical exercise depending on artistic fitness and the difficulty of the movement (maximal individual value 173 beats/min). Additionally, a large variation might be caused through intrathoracic pressure changes, changing exertion, respiratory influences and emotion. The electrocardiogram showed no pathological events. In general, clarinet playing at a professional level imposes strain on ventilation and circulation but usually not on a pathophysiological level.

Swimming Three Ice Miles within Fifteen Hours.

PubMed

Stjepanovic, Mirko; Nikolaidis, Pantelis T.; Knechtle, Beat

2017-08-31

Ice Mile swimming (1608 m in water of below 5 °Celsius) is becoming increasingly popular. This case study aimed to identify body core temperature and selected haematological and biochemical parameters before and after repeated Ice Miles. An experienced ice swimmer completed three consecutive Ice Miles within 15 h. Swim times, body core temperatures, and selected urinary and haematological parameters were recorded. Body core temperature reached its maximum between 5, 8 and 15 min after immersion (37.7°C, 38.1°C, and 38.0°C, respectively). The swimmer suffered hypothermia during the first Ice Mile (35.4°C) and body core temperature dropped furthermore to 34.5°C during recovery after the first Ice Mile. He developed a metabolic acidosis in both the first and the last Ice Mile (pH 7.31 and pH 7.34, respectively). We observed hyperkalaemia ([K⁺] > 5.5 mM) after the second Ice Mile (6.9 mM). This was followed by a drop in [K⁺] to3.7 mM after the third Ice Mile. Anticipatory thermogenesis (i.e. an initial increase of body core temperature after immersion in ice cold water) seems to be a physiological response in a trained athlete. The results suggest that swimming in ice-cold water leads to a metabolic acidosis, which the swimmer compensates with hyperventilation (i.e. leading to respiratory alkalosis). The shift of serum [K⁺] could increase the risk of a cardiac arrhythmia. Further studies addressing the physiology and potential risks of Ice Mile swimming are required to substantiate this finding.

Somatic expressions of grief and psychosomatic illness in the works of William Shakespeare and his coevals.

PubMed

Heaton, Kenneth W

2012-10-01

To find out if Shakespeare, famed for his insights into human nature, is exceptional in how much his characters express grief through somatic symptoms and signs, and by physical illness. The texts of all large-scale works currently attributed to Shakespeare (39 plays, 3 long narrative poems) were systematically searched for bodily changes and for evidence of grief as dominating the character's emotional state at the time. The findings were compared with those from a search of 46 works, similar in genre, by 15 prominent playwrights active at the same time as Shakespeare. In Shakespeare 31 different grief-associated symptoms or signs were found, in 140 instances. They are present in all but two of his plays and long poems and involve most systems of the body. With non-Shakespearean writers there were 26 kinds, 132 instances. Twenty-two changes are common to both groups, including fainting, death (sudden or after a decline), and wrinkled face, and symptoms such as malaise, fatigue, awareness of the heart-beat, and anorexia. Ten somatic expressions of grief were found only in Shakespeare, including hyperventilation, hair turning white and premature childbirth. Four were found only in his contemporaries but were trivial or unconvincing. Deaths and non-fatal illnesses are prevalent in Shakespeare. Grieving Shakespearean characters exhibit many somatic symptoms and signs and a wide range of psychosomatic illnesses. This panoply of psychosomatic phenomena may be an artistic artefact but it also confirms that Shakespeare's empathy with grieving humanity was unrivalled. Copyright © 2012 Elsevier Inc. All rights reserved.

Body-conscious Shakespeare: sensory disturbances in troubled characters.

PubMed

Heaton, Kenneth W

2011-12-01

It is widely accepted that Shakespeare was unique in the range of his insights into the human mind, but the way his characters reveal their mental states through bodily sensations has not been systematically explored. The author has searched for these phenomena in the 42 major works of Shakespeare and in 46 genre-matched works by his contemporaries, and in this paper the author focuses on sensory changes other than those involving vision, taste, the heart and the alimentary tract (all considered in other papers). Vertigo is experienced by five distressed Shakespearean characters, all men, but not at all by the other writers' characters. Breathlessness, probably representing hyperventilation, occurs eleven times in Shakespeare's works but only twice in the other writers' works. Fatigue, expressing grief, is articulated by several Shakespearean characters including Hamlet. It features less often in the others' works. Deafness at a time of high emotion is mentioned by Shakespeare several times but usually by a character 'turning a deaf ear', consciously or unconsciously. To the other writers, ears show emotion only by burning or itching. Blunting of touch and pain and their opposites of hypersensitivity to touch and pain are all to be found in Shakespeare's works when a character is distressed or excited, but not so with his contemporaries' works. Faint feelings and cold feelings are also more common in the works of Shakespeare. Overall, therefore, Shakespeare was exceptional in his use of sensory disturbances to express emotional upset. This may be a conscious literary device or a sign of exceptional awareness of bodily sensations.

Sleep apnoea in heart failure: To treat or not to treat?

PubMed

Naughton, Matthew T; Kee, Kirk

2017-02-01

Heart failure (HF) and sleep apnoea are common disorders which frequently coexist. Two main types of apnoea occur: one is obstructive which, through recurring episodes of snoring, hypoxaemia, large negative intra-thoracic pressures and arousals from sleep leading to downstream inflammatory and autonomic nervous system changes, is thought to be a causative factor to the development of systemic hypertension and HF. The other type of apnoea, Cheyne-Stokes respiration with central sleep apnoea (CSR-CSA), is characterized by an oscillatory pattern of ventilation with a prevailing hyperventilation-induced hypocapnia, often in the absence of significant hypoxaemia and snoring, and is thought to be a consequence of advanced HF-related low cardiac output, high sympathetic nervous system activation and pulmonary congestion. CSR-CSA may be a compensatory response to advanced HF. Rostral fluid shift during sleep may play an important role in the pathogenesis of both obstructive sleep apnoea (OSA) and CSA. Studies of positive airway pressure (PAP) treatment of OSA and CSA in HF have shown short-term improvements in cardiac and autonomic function; however, there is no evidence of improved survival. Loop gain may provide useful marker of continuous PAP (CPAP) responsiveness in patients with central apnoea. A greater understanding of the pathophysiology of the interaction between obstructive and central apnoea and the various types of HF, and the mechanisms of therapies, such as PAP, is required to develop new strategies to overcome the disabling symptoms, and perhaps improve the mortality, that accompany HF with sleep apnoea. © 2016 Asian Pacific Society of Respirology.

Cerebral blood flow and metabolism during exercise: implications for fatigue.

PubMed

Secher, Neils H; Seifert, Thomas; Van Lieshout, Johannes J

2008-01-01

During exercise: the Kety-Schmidt-determined cerebral blood flow (CBF) does not change because the jugular vein is collapsed in the upright position. In contrast, when CBF is evaluated by (133)Xe clearance, by flow in the internal carotid artery, or by flow velocity in basal cerebral arteries, a approximately 25% increase is detected with a parallel increase in metabolism. During activation, an increase in cerebral O(2) supply is required because there is no capillary recruitment within the brain and increased metabolism becomes dependent on an enhanced gradient for oxygen diffusion. During maximal whole body exercise, however, cerebral oxygenation decreases because of eventual arterial desaturation and marked hyperventilation-related hypocapnia of consequence for CBF. Reduced cerebral oxygenation affects recruitment of motor units, and supplemental O(2) enhances cerebral oxygenation and work capacity without effects on muscle oxygenation. Also, the work of breathing and the increasing temperature of the brain during exercise are of importance for the development of so-called central fatigue. During prolonged exercise, the perceived exertion is related to accumulation of ammonia in the brain, and data support the theory that glycogen depletion in astrocytes limits the ability of the brain to accelerate its metabolism during activation. The release of interleukin-6 from the brain when exercise is prolonged may represent a signaling pathway in matching the metabolic response of the brain. Preliminary data suggest a coupling between the circulatory and metabolic perturbations in the brain during strenuous exercise and the ability of the brain to access slow-twitch muscle fiber populations.

Household exposure and animal-bite surveillance following human rabies detection in Southern Ghana.

PubMed

Afakye, Kofi; Kenu, Ernest; Nyarko, Kofi Mensah; Johnson, Sherry Ama Mawuko; Wongnaah, Florence; Bonsu, George Kwame

2016-01-01

Rabies remains a neglected tropical zoonotic disease with 100% case fatality rate and estimated 6,000 global mortality annually, and yet vaccine preventable. In Ghana, rabies outbreaks receive poor response. We investigated rabies in a 5-year old boy to find the source of infection, identify exposed persons for post-exposure prophylaxis and describe animal-bite surveillance in Manya-Krobo District of Ghana. We actively searched for cases and exposures by interviewing household members of the victim, schoolmates, and health professionals using WHO case definition, interview guide and checklist. We reviewed health and veterinary records and reports, and interviewed stakeholders. Descriptive data analyses were carried out and presented using tables and charts. Recorded responses were transcribed into thematic areas and analysed. Child had dog-bite at the wrist, and developed hyperactivity, hydrophobia and hyperventilation 2 months post bite. He was hospitalised and died from respiratory failure day 3 after admission. Thirty-three persons were exposed to rabies infectious material. Females were 66%, age-groups 5-15yrs and 30-59 yrs were 33.3% and 39.4% respectively. A third (11/33) were category II exposure by WHO classification and were recommended for post-exposure prophylaxis. Surveillance records showed ninety-two animal-bite cases were reported for past 12 months. Half were females, and 18-59yrs age-group was 43%. Surveillance data quality was poor. Rabies remains a public health burden inGhana with domestic dog as reservoir of the virus and females more vulnerable to secondary exposures. Health education on rabies should be intensified, and robust animal-bite surveillance system put in place.

Proton detection and breathing regulation by the retrotrapezoid nucleus

PubMed Central

Bayliss, Douglas A.; Stornetta, Ruth L.; Ludwig, Marie‐Gabrielle; Kumar, Natasha N.; Shi, Yingtang; Burke, Peter G. R.; Kanbar, Roy; Basting, Tyler M.; Holloway, Benjamin B.; Wenker, Ian C.

2016-01-01

Abstract We discuss recent evidence which suggests that the principal central respiratory chemoreceptors are located within the retrotrapezoid nucleus (RTN) and that RTN neurons are directly sensitive to [H+]. RTN neurons are glutamatergic. In vitro, their activation by [H+] requires expression of a proton‐activated G protein‐coupled receptor (GPR4) and a proton‐modulated potassium channel (TASK‐2) whose transcripts are undetectable in astrocytes and the rest of the lower brainstem respiratory network. The pH response of RTN neurons is modulated by surrounding astrocytes but genetic deletion of RTN neurons or deletion of both GPR4 and TASK‐2 virtually eliminates the central respiratory chemoreflex. Thus, although this reflex is regulated by innumerable brain pathways, it seems to operate predominantly by modulating the discharge rate of RTN neurons, and the activation of RTN neurons by hypercapnia may ultimately derive from their intrinsic pH sensitivity. RTN neurons increase lung ventilation by stimulating multiple aspects of breathing simultaneously. They stimulate breathing about equally during quiet wake and non‐rapid eye movement (REM) sleep, and to a lesser degree during REM sleep. The activity of RTN neurons is regulated by inhibitory feedback and by excitatory inputs, notably from the carotid bodies. The latter input operates during normo‐ or hypercapnia but fails to activate RTN neurons under hypocapnic conditions. RTN inhibition probably limits the degree of hyperventilation produced by hypocapnic hypoxia. RTN neurons are also activated by inputs from serotonergic neurons and hypothalamic neurons. The absence of RTN neurons probably underlies the sleep apnoea and lack of chemoreflex that characterize congenital central hypoventilation syndrome. PMID:26748771

Guinea Pig Oxygen-Sensing and Carotid Body Functional Properties

PubMed Central

Gonzalez-Obeso, Elvira; Docio, Inmaculada; Olea, Elena; Cogolludo, Angel; Obeso, Ana; Rocher, Asuncion; Gomez-Niño, Angela

2017-01-01

Mammals have developed different mechanisms to maintain oxygen supply to cells in response to hypoxia. One of those mechanisms, the carotid body (CB) chemoreceptors, is able to detect physiological hypoxia and generate homeostatic reflex responses, mainly ventilatory and cardiovascular. It has been reported that guinea pigs, originally from the Andes, have a reduced ventilatory response to hypoxia compared to other mammals, implying that CB are not completely functional, which has been related to genetically/epigenetically determined poor hypoxia-driven CB reflex. This study was performed to check the guinea pig CB response to hypoxia compared to the well-known rat hypoxic response. These experiments have explored ventilatory parameters breathing different gases mixtures, cardiovascular responses to acute hypoxia, in vitro CB response to hypoxia and other stimuli and isolated guinea pig chemoreceptor cells properties. Our findings show that guinea pigs are hypotensive and have lower arterial pO2 than rats, probably related to a low sympathetic tone and high hemoglobin affinity. Those characteristics could represent a higher tolerance to hypoxic environment than other rodents. We also find that although CB are hypo-functional not showing chronic hypoxia sensitization, a small percentage of isolated carotid body chemoreceptor cells contain tyrosine hydroxylase enzyme and voltage-dependent K+ currents and therefore can be depolarized. However hypoxia does not modify intracellular Ca2+ levels or catecholamine secretion. Guinea pigs are able to hyperventilate only in response to intense acute hypoxic stimulus, but hypercapnic response is similar to rats. Whether other brain areas are also activated by hypoxia in guinea pigs remains to be studied. PMID:28533756

Guinea Pig Oxygen-Sensing and Carotid Body Functional Properties.

PubMed

Gonzalez-Obeso, Elvira; Docio, Inmaculada; Olea, Elena; Cogolludo, Angel; Obeso, Ana; Rocher, Asuncion; Gomez-Niño, Angela

2017-01-01

Mammals have developed different mechanisms to maintain oxygen supply to cells in response to hypoxia. One of those mechanisms, the carotid body (CB) chemoreceptors, is able to detect physiological hypoxia and generate homeostatic reflex responses, mainly ventilatory and cardiovascular. It has been reported that guinea pigs, originally from the Andes, have a reduced ventilatory response to hypoxia compared to other mammals, implying that CB are not completely functional, which has been related to genetically/epigenetically determined poor hypoxia-driven CB reflex. This study was performed to check the guinea pig CB response to hypoxia compared to the well-known rat hypoxic response. These experiments have explored ventilatory parameters breathing different gases mixtures, cardiovascular responses to acute hypoxia, in vitro CB response to hypoxia and other stimuli and isolated guinea pig chemoreceptor cells properties. Our findings show that guinea pigs are hypotensive and have lower arterial pO 2 than rats, probably related to a low sympathetic tone and high hemoglobin affinity. Those characteristics could represent a higher tolerance to hypoxic environment than other rodents. We also find that although CB are hypo-functional not showing chronic hypoxia sensitization, a small percentage of isolated carotid body chemoreceptor cells contain tyrosine hydroxylase enzyme and voltage-dependent K + currents and therefore can be depolarized. However hypoxia does not modify intracellular Ca 2+ levels or catecholamine secretion. Guinea pigs are able to hyperventilate only in response to intense acute hypoxic stimulus, but hypercapnic response is similar to rats. Whether other brain areas are also activated by hypoxia in guinea pigs remains to be studied.

Demographic profile and extent of healthcare resource utilisation of patients with severe traumatic brain injury: still a major public health problem.

PubMed

Wee, Jing Zhong; Yang, Yun Rui Jasmine; Lee, Qian Yi Ruth; Cao, Kelly; Chong, Chin Ted

2016-09-01

Trauma is the fifth principal cause of death in Singapore, with traumatic brain injury (TBI) being the leading specific subordinate cause. This study was an eight-year retrospective review of the demographic profiles of patients with severe TBI who were admitted to the neurointensive care unit (NICU) of the National Neuroscience Institute at Tan Tock Seng Hospital, Singapore, between 2004 and 2011. A total of 780 TBI patients were admitted during the study period; 365 (46.8%) patients sustained severe TBI (i.e. Glasgow Coma Scale score ≤ 8), with the majority (75.3%) being male. The ages of patients with severe TBI ranged from 14-93 years, with a bimodal preponderance in young adults (i.e. 21-40 years) and elderly persons (i.e. > 60 years). Motor vehicle accidents (48.8%) and falls (42.5%) were the main mechanisms of injury. Invasive line monitoring was frequently employed; invasive arterial blood pressure monitoring and central venous pressure monitoring were used in 81.6% and 60.0% of the patients, respectively, while intracranial pressure (ICP) measurement was required in 47.4% of the patients. The use of tiered therapy to control ICP (e.g. sedation, osmotherapy, cerebrospinal fluid drainage, moderate hyperventilation and barbiturate-induced coma) converged with international practices. The high-risk groups for severe TBI were young adults and elderly persons involved in motor vehicle accidents and falls, respectively. In the NICU, the care of patients with severe TBI requires heavy utilisation of resources. The healthcare burden of these patients extends beyond the acute critical care phase.

Panic disorder respiratory subtype: psychopathology, laboratory challenge tests, and response to treatment.

PubMed

Freire, Rafael C; Perna, Giampaolo; Nardi, Antonio E

2010-01-01

Our objective is to summarize the new findings concerning the respiratory subtype (RS) of panic disorder (PD) since its first description. Two searches were made in the Institute for Scientific Information Web of Science: with the keywords "panic disorder" and "respiratory symptoms," and all articles that cited Briggs and colleagues' 1993 article "Subtyping of Panic Disorder by Symptom Profile" (Br J Psychiatry 1993;163:201-9). Altogether, 133 articles were reviewed. We describe and discuss RS epidemiology, genetics, psychopathology, demographic features, clinical features, correlations with the respiratory system, traumatic suffocation history, provocative tests, and nocturnal panic. Compared to patients with the nonrespiratory subtype (non-RS), the RS patients had higher familial history of PD, lower comorbidity with depression, longer duration of illness, lower neuroticism scores, and higher scores in severity scales, such as the Panic and Agoraphobia Scale, Panic-Agoraphobia Spectrum scale and the Clinical Global Impression scale. Tests to induce panic attacks, such as those with CO(2), hyperventilation, and caffeine, produce panic attacks in a higher proportion of RS patients than non-RS patients. Differences in the subtypes' improvement with the pharmacologic treatment were found. There are also some controversial findings regarding the RS, including the age of onset of PD, and alcohol and tobacco use in RS patients. Some characteristics, such as the increased sensitivity to CO(2) and the higher familial history of PD, clearly distinguish the RS from the non-RS. Nevertheless, there are also controversial findings. More studies are needed to determine the validity of the RS subtype.

Does ammonia trigger hyperventilation in the elasmobranch, Squalus acanthias suckleyi?

PubMed

De Boeck, Gudrun; Wood, Chris M

2015-01-15

We examined the ventilatory response of the spiny dogfish, to elevated internal or environmental ammonia. Sharks were injected via arterial catheters with ammonia solutions or their Na salt equivalents sufficient to increase plasma total ammonia concentration [TAmm]a by 3-5 fold from 145±21μM to 447±150μM using NH4HCO3 and a maximum of 766±100μM using (NH4)2SO4. (NH4)2SO4 caused a small increase in ventilation frequency (+14%) and a large increase in amplitude (+69%), while Na2SO4 did not. However, CO2 partial pressure (PaCO2) also increased and arterial pHa and plasma bicarbonate concentration ([HCO3(-)]a) decreased. NH4HCO3 caused a smaller increase in plasma ammonia resulting in a smaller but significant, short lived increases in ventilation frequency (+6%) and amplitude (36%), together with a rise in PaCO2 and [HCO3(-)]a. Injection with NaHCO3 which increased pHa and [HCO3(-)]a did not change ventilation. Plasma ammonia concentration correlated significantly with ventilation amplitude, while ventilation frequency showed a (negative) correlation with pHa. Exposure to high environmental ammonia (1500μM NH4HCO3) did not induce changes in ventilation until plasma [TAmm]a increased and ventilation amplitude (but not frequency) increased in parallel. We conclude that internal ammonia stimulates ventilation in spiny dogfish, especially amplitude or stroke volume, while environmental ammonia only stimulates ventilation after ammonia diffuses into the bloodstream. Copyright © 2014 Elsevier B.V. All rights reserved.

Hematological variations at rest and during maximal and submaximal exercise in a cold (0°C) environment

NASA Astrophysics Data System (ADS)

Vogelaere, P.; Brasseur, M.; Quirion, A.; Leclercq, R.; Laurencelle, L.; Bekaert, S.

1990-03-01

The affect of negative thermal stress on hematological variables at rest, and during submaximal (sub ex) and maximal exercise (max ex) were observed for young males who volunteered in two experimental sessions, performed in cold (0°C) and in normal room temperature (20°C). At rest, hematological variables such as RBC and derivates Hb and Hct were significantly increased ( P<0.05) during cold stress exposure, while plasma volume decreased. The findings of this study suggest that the major factor inducing hypovolemia during low thermal stress can be imputed to local plasma water-shift mechanisms and especially to a transient shift of plasma water from intrato extravascular compartments. Rest values for WBC and platelets (Pla) were also slightly increased during cold stress exposure. However this increase can partly be related to hemoconcentration but also to the cold induced hyperventilation activating the lung circulation. Maximal exhaustive exercise induced, in both experimental temperatures, significant ( P<0.05) increments of RBC, Hb, Hct, and WBC while plasma volume decreased. However, Pla increase was less marked. On the other hand, cold stress raised slightly the observed variations of the different hematological variables. Submaximal exercise induced a similar, though non-significant, pattern for the different hematological variables in both experimental conditions. Observed plasma volume (Δ PV%) reduction appears during exercise. However cold stress induced resting plasma volume variations that are transferred at every exercise level. Neither exercise nor cold inducement significantly modified the hematological indices (MCH, MCV, MCHC). In conclusion hematological variables are affected by cold stress exposure, even when subjects perform a physical activity.

Non-invasive assessment of cerebral microcirculation with diffuse optics and coherent hemodynamics spectroscopy

NASA Astrophysics Data System (ADS)

Fantini, Sergio; Sassaroli, Angelo; Kainerstorfer, Jana M.; Tgavalekos, Kristen T.; Zang, Xuan

2016-03-01

We describe the general principles and initial results of coherent hemodynamics spectroscopy (CHS), which is a new technique for the quantitative assessment of cerebral hemodynamics on the basis of dynamic near-infrared spectroscopy (NIRS) measurements. The two components of CHS are (1) dynamic measurements of coherent cerebral hemodynamics in the form of oscillations at multiple frequencies (frequency domain) or temporal transients (time domain), and (2) their quantitative analysis with a dynamic mathematical model that relates the concentration and oxygen saturation of hemoglobin in tissue to cerebral blood volume (CBV), cerebral blood flow (CBF), and cerebral metabolic rate of oxygen (CMRO2). In particular, CHS can provide absolute measurements and dynamic monitoring of CBF, and quantitative measures of cerebral autoregulation. We report initial results of CBF measurements in hemodialysis patients, where we found a lower CBF (54 +/- 16 ml/(100 g-min)) compared to a group of healthy controls (95 +/- 11 ml/(100 g-min)). We also report CHS measurements of cerebral autoregulation, where a quantitative index of autoregulation (its cutoff frequency) was found to be significantly greater in healthy subjects during hyperventilation (0.034 +/- 0.005 Hz) than during normal breathing (0.017 +/- 0.002 Hz). We also present our approach to depth resolved CHS, based on multi-distance, frequency-domain NIRS data and a two-layer diffusion model, to enhance sensitivity to cerebral tissue. CHS offers a potentially powerful approach to the quantitative assessment and continuous monitoring of local brain perfusion at the microcirculation level, with prospective brain mapping capabilities of research and clinical significance.

Videographic assessment of cardiopulmonary resuscitation quality in the pediatric emergency department.

PubMed

Donoghue, Aaron; Hsieh, Ting-Chang; Myers, Sage; Mak, Allison; Sutton, Robert; Nadkarni, Vinay

2015-06-01

To describe the adherence to guidelines for CPR in a tertiary pediatric emergency department (ED) where resuscitations are reviewed by videorecording. Resuscitations in a tertiary pediatric ED are videorecorded as part of a quality improvement project. Patients receiving CPR under videorecorded conditions were eligible for inclusion. CPR parameters were quantified by retrospective review. Data were described by 30-s epoch (compression rate, ventilation rate, compression:ventilation ratio), by segment (duration of single providers' compressions) and by overall event (compression fraction). Duration of interruptions in compressions was measured; tasks completed during pauses were tabulated. 33 children received CPR under videorecorded conditions. A total of 650 min of CPR were analyzed. Chest compressions were performed at <100/min in 90/714 (13%) of epochs; 100-120/min in 309/714 (43%); >120/min in 315/714 (44%). Ventilations were 6-12 breaths/min in 201/708 (23%) of epochs and >12/min in 489/708 (70%). During CPR without an artificial airway, compression:ventilation coordination (15:2) was done in 93/234 (40%) of epochs. 178 pauses in CPR occurred; 120 (67%) were <10s in duration. Of 370 segments of compressions by individual providers, 282/370 (76%) were <2 min in duration. Median compression fraction was 91% (range 88-100%). CPR in a tertiary pediatric ED frequently met recommended parameters for compression rate, pause duration, and compression fraction. Hyperventilation and failure of C:V coordination were very common. Future studies should focus on the impact of training methods on CPR performance as documented by videorecording. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Exercise physiological responses to drug treatments in chronic thromboembolic pulmonary hypertension.

PubMed

Charalampopoulos, Athanasios; Gibbs, J Simon R; Davies, Rachel J; Gin-Sing, Wendy; Murphy, Kevin; Sheares, Karen K; Pepke-Zaba, Joanna; Jenkins, David P; Howard, Luke S

2016-09-01

We tested the hypothesis that patients with chronic thromboembolic pulmonary hypertension (CTEPH) that was deemed to be inoperable were more likely to respond to drugs for treating pulmonary arterial hypertension (PAH) by using cardiopulmonary exercise (CPX) testing than those with CTEPH that was deemed to be operable. We analyzed CPX testing data of all patients with CTEPH who were treated with PAH drugs and had undergone CPX testing before and after treatment at a single pulmonary hypertension center between February 2009 and March 2013. Suitability for pulmonary endarterectomy (PEA) was decided by experts in PEA who were associated with a treatment center. The group with inoperable CTEPH included 16 patients, the operable group included 26 patients. There were no differences in demographics and baseline hemodynamic data between the groups. Unlike patients in the operable group, after drug treatment patients with inoperable CTEPH had a significantly higher peak V̇o2 (P < 0.001), work load (P = 0.002), and oxygen pulse (P < 0.001). In terms of gas exchange, there was an overall net trend toward improved V̇e/V̇co2 in the group with inoperable CTEPH, with an increased PaCO2 (P = 0.01), suggesting reduced hyperventilation. No changes were observed in patients with operable CTEPH. In conclusion, treatment with PAH drug therapy reveals important pathophysiological differences between inoperable and operable CTEPH, with significant pulmonary vascular and cardiac responses in inoperable disease. Drug effects on exercise function observed in inoperable CTEPH cannot be translated to all forms of CTEPH. Copyright © 2016 the American Physiological Society.

Using screen-based simulation of inhaled anaesthetic delivery to improve patient care.

PubMed

Philip, J H

2015-12-01

Screen-based simulation can improve patient care by giving novices and experienced clinicians insight into drug behaviour. Gas Man(®) is a screen-based simulation program that depicts pictorially and graphically the anaesthetic gas and vapour tension from the vaporizer to the site of action, namely the brain and spinal cord. The gases and vapours depicted are desflurane, enflurane, ether, halothane, isoflurane, nitrogen, nitrous oxide, sevoflurane, and xenon. Multiple agents can be administered simultaneously or individually and the results shown on an overlay graph. Practice exercises provide in-depth knowledge of the subject matter. Experienced clinicians can simulate anaesthesia occurrences and practices for application to their clinical practice, and publish the results to benefit others to improve patient care. Published studies using this screen-based simulation have led to a number of findings, as follows: changing from isoflurane to desflurane toward the end of anaesthesia does not accelerate recovery in humans; vital capacity induction can produce loss of consciousness in 45 s; simulated context-sensitive decrement times explain recovery profiles; hyperventilation does not dramatically speed emergence; high fresh gas flow is wasteful; fresh gas flow and not the vaporizer setting should be reduced during intubation; re-anaesthetization can occur with severe hypoventilation after extubation; and in re-anaesthetization, the anaesthetic redistributes from skeletal muscle. Researchers using screen-based simulations can study fewer subjects to reach valid conclusions that impact clinical care. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Exogenous sphingosine-1-phosphate boosts acclimatization in rats exposed to acute hypobaric hypoxia: assessment of haematological and metabolic effects.

PubMed

Chawla, Sonam; Rahar, Babita; Singh, Mrinalini; Bansal, Anju; Saraswat, Deepika; Saxena, Shweta

2014-01-01

The physiological challenges posed by hypobaric hypoxia warrant exploration of pharmacological entities to improve acclimatization to hypoxia. The present study investigates the preclinical efficacy of sphingosine-1-phosphate (S1P) to improve acclimatization to simulated hypobaric hypoxia. Efficacy of intravenously administered S1P in improving haematological and metabolic acclimatization was evaluated in rats exposed to simulated acute hypobaric hypoxia (7620 m for 6 hours) following S1P pre-treatment for three days. Altitude exposure of the control rats caused systemic hypoxia, hypocapnia (plausible sign of hyperventilation) and respiratory alkalosis due to suboptimal renal compensation indicated by an overt alkaline pH of the mixed venous blood. This was associated with pronounced energy deficit in the hepatic tissue along with systemic oxidative stress and inflammation. S1P pre-treatment improved blood oxygen-carrying-capacity by increasing haemoglobin, haematocrit, and RBC count, probably as an outcome of hypoxia inducible factor-1α mediated erythropoiesis and renal S1P receptor 1 mediated haemoconcentation. The improved partial pressure of oxygen in the blood could further restore aerobic respiration and increase ATP content in the hepatic tissue of S1P treated animals. S1P could also protect the animals from hypoxia mediated oxidative stress and inflammation. The study findings highlight S1P's merits as a preconditioning agent for improving acclimatization to acute hypobaric hypoxia exposure. The results may have long term clinical application for improving physiological acclimatization of subjects venturing into high altitude for occupational or recreational purposes.

Exogenous Sphingosine-1-Phosphate Boosts Acclimatization in Rats Exposed to Acute Hypobaric Hypoxia: Assessment of Haematological and Metabolic Effects

PubMed Central

Chawla, Sonam; Rahar, Babita; Singh, Mrinalini; Bansal, Anju; Saraswat, Deepika; Saxena, Shweta

2014-01-01

Background The physiological challenges posed by hypobaric hypoxia warrant exploration of pharmacological entities to improve acclimatization to hypoxia. The present study investigates the preclinical efficacy of sphingosine-1-phosphate (S1P) to improve acclimatization to simulated hypobaric hypoxia. Experimental Approach Efficacy of intravenously administered S1P in improving haematological and metabolic acclimatization was evaluated in rats exposed to simulated acute hypobaric hypoxia (7620m for 6 hours) following S1P pre-treatment for three days. Major Findings Altitude exposure of the control rats caused systemic hypoxia, hypocapnia (plausible sign of hyperventilation) and respiratory alkalosis due to suboptimal renal compensation indicated by an overt alkaline pH of the mixed venous blood. This was associated with pronounced energy deficit in the hepatic tissue along with systemic oxidative stress and inflammation. S1P pre-treatment improved blood oxygen-carrying-capacity by increasing haemoglobin, haematocrit, and RBC count, probably as an outcome of hypoxia inducible factor-1α mediated erythropoiesis and renal S1P receptor 1 mediated haemoconcentation. The improved partial pressure of oxygen in the blood could further restore aerobic respiration and increase ATP content in the hepatic tissue of S1P treated animals. S1P could also protect the animals from hypoxia mediated oxidative stress and inflammation. Conclusion The study findings highlight S1P’s merits as a preconditioning agent for improving acclimatization to acute hypobaric hypoxia exposure. The results may have long term clinical application for improving physiological acclimatization of subjects venturing into high altitude for occupational or recreational purposes. PMID:24887065

Cerebrovascular reactivity is increased with acclimatization to 3,454 m altitude.

PubMed

Flück, Daniela; Siebenmann, Christoph; Keiser, Stefanie; Cathomen, Adrian; Lundby, Carsten

2015-08-01

Controversy exists regarding the effect of high-altitude exposure on cerebrovascular CO2 reactivity (CVR). Confounding factors in previous studies include the use of different experimental approaches, ascent profiles, duration and severity of exposure and plausibly environmental factors associated with altitude exposure. One aim of the present study was to determine CVR throughout acclimatization to high altitude when controlling for these. Middle cerebral artery mean velocity (MCAv mean) CVR was assessed during hyperventilation (hypocapnia) and CO2 administration (hypercapnia) with background normoxia (sea level (SL)) and hypoxia (3,454 m) in nine healthy volunteers (26 ± 4 years (mean ± s.d.)) at SL, and after 30 minutes (HA0), 3 (HA3) and 22 (HA22) days of high-altitude (3,454 m) exposure. At altitude, ventilation was increased whereas MCAv mean was not altered. Hypercapnic CVR was decreased at HA0 (1.16% ± 0.16%/mm Hg, mean ± s.e.m.), whereas both hyper- and hypocapnic CVR were increased at HA3 (3.13% ± 0.18% and 2.96% ± 0.10%/mm Hg) and HA22 (3.32% ± 0.12% and 3.24% ± 0.14%/mm Hg) compared with SL (1.98% ± 0.22% and 2.38% ± 0.10%/mm Hg; P < 0.01) regardless of background oxygenation. Cerebrovascular conductance (MCAv mean/mean arterial pressure) CVR was determined to account for blood pressure changes and revealed an attenuated response. Collectively our results show that hypocapnic and hypercapnic CVR are both elevated with acclimatization to high altitude.

Cerebrovascular reactivity is increased with acclimatization to 3,454 m altitude

PubMed Central

Flück, Daniela; Siebenmann, Christoph; Keiser, Stefanie; Cathomen, Adrian; Lundby, Carsten

2015-01-01

Controversy exists regarding the effect of high-altitude exposure on cerebrovascular CO2 reactivity (CVR). Confounding factors in previous studies include the use of different experimental approaches, ascent profiles, duration and severity of exposure and plausibly environmental factors associated with altitude exposure. One aim of the present study was to determine CVR throughout acclimatization to high altitude when controlling for these. Middle cerebral artery mean velocity (MCAvmean) CVR was assessed during hyperventilation (hypocapnia) and CO2 administration (hypercapnia) with background normoxia (sea level (SL)) and hypoxia (3,454 m) in nine healthy volunteers (26±4 years (mean±s.d.)) at SL, and after 30 minutes (HA0), 3 (HA3) and 22 (HA22) days of high-altitude (3,454 m) exposure. At altitude, ventilation was increased whereas MCAvmean was not altered. Hypercapnic CVR was decreased at HA0 (1.16%±0.16%/mm Hg, mean±s.e.m.), whereas both hyper- and hypocapnic CVR were increased at HA3 (3.13%±0.18% and 2.96%±0.10%/mm Hg) and HA22 (3.32%±0.12% and 3.24%±0.14%/mm Hg) compared with SL (1.98%±0.22% and 2.38%±0.10%/mm Hg; P<0.01) regardless of background oxygenation. Cerebrovascular conductance (MCAvmean/mean arterial pressure) CVR was determined to account for blood pressure changes and revealed an attenuated response. Collectively our results show that hypocapnic and hypercapnic CVR are both elevated with acclimatization to high altitude. PMID:25806704

Feasibility of the capnogram to monitor ventilation rate during cardiopulmonary resuscitation.

PubMed

Aramendi, Elisabete; Elola, Andoni; Alonso, Erik; Irusta, Unai; Daya, Mohamud; Russell, James K; Hubner, Pia; Sterz, Fritz

2017-01-01

The rates of chest compressions (CCs) and ventilations are both important metrics to monitor the quality of cardiopulmonary resuscitation (CPR). Capnography permits monitoring ventilation, but the CCs provided during CPR corrupt the capnogram and compromise the accuracy of automatic ventilation detectors. The aim of this study was to evaluate the feasibility of an automatic algorithm based on the capnogram to detect ventilations and provide feedback on ventilation rate during CPR, specifically addressing intervals where CCs are delivered. The dataset used to develop and test the algorithm contained in-hospital and out-of-hospital cardiac arrest episodes. The method relies on adaptive thresholding to detect ventilations in the first derivative of the capnogram. The performance of the detector was reported in terms of sensitivity (SE) and Positive Predictive Value (PPV). The overall performance was reported in terms of the rate error and errors in the hyperventilation alarms. Results were given separately for the intervals with CCs. A total of 83 episodes were considered, resulting in 4880min and 46,740 ventilations (8741 during CCs). The method showed an overall SE/PPV above 99% and 97% respectively, even in intervals with CCs. The error for the ventilation rate was below 1.8min -1 in any group, and >99% of the ventilation alarms were correctly detected. A method to provide accurate feedback on ventilation rate using only the capnogram is proposed. Its accuracy was proven even in intervals where canpography signal was severely corrupted by CCs. This algorithm could be integrated into monitor/defibrillators to provide reliable feedback on ventilation rate during CPR. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Prospective impact of panic disorder and panic-anxiety on asthma control, health service use, and quality of life in adult patients with asthma over a 4-year follow-up.

PubMed

Favreau, Helene; Bacon, Simon L; Labrecque, Manon; Lavoie, Kim L

2014-02-01

Background Panic disorder (PD) is a common anxiety disorder among asthmatic patients with overlapping symptoms (e.g., hyperventilation). However, the longitudinal impact of PD on asthma control remains poorly understood. This study assessed the impact of PD and panic-anxiety on asthma control over a 4.3-year follow-up in 643 adult asthmatic patients. Methods Consecutive patients presenting to a tertiary asthma clinic underwent a sociodemographic, medical history, and psychiatric (Primary Care Evaluation of Mental Disorders) interview and completed questionnaires including the Anxiety Sensitivity Index (ASI) to assess panic-anxiety. At follow-up, patients completed the Asthma Control (ACQ) and Asthma Quality of Life (AQLQ) questionnaires and reported emergency department visits and hospitalizations during the follow-up. Results Baseline frequency of PD was 10% (n = 65). In fully adjusted models, analyses revealed that PD and ASI scores predicted worse follow-up ACQ total scores (β = 0.292, p = .037; β = 0.012, p = .003) but not AQLQ total scores. ASI scores also predicted greater nocturnal and waking symptoms, activity limitations, and bronchodilator use on the ACQ (β = 0.012-0.018, p < .05) as well as lower symptom (β = -0.012, p = .006) and emotional distress (β = -0.014, p = .002) subscale scores on the AQLQ. Neither PD nor ASI scores were associated with hospitalizations, although ASI scores (but not PD) were associated with an increased risk of emergency department visits (relative risk = 1.023, 95% confidence interval = 1.001-1.044). Conclusions PD and anxiety sensitivity are prospectively associated with poorer asthma control and may be important targets for treatment.

Metronome improves compression and ventilation rates during CPR on a manikin in a randomized trial.

PubMed

Kern, Karl B; Stickney, Ronald E; Gallison, Leanne; Smith, Robert E

2010-02-01

We hypothesized that a unique tock and voice metronome could prevent both suboptimal chest compression rates and hyperventilation. A prospective, randomized, parallel design study involving 34 pairs of paid firefighter/emergency medical technicians (EMTs) performing two-rescuer CPR using a Laerdal SkillReporter Resusci Anne manikin with and without metronome guidance was performed. Each CPR session consisted of 2 min of 30:2 CPR with an unsecured airway, then 4 min of CPR with a secured airway (continuous compressions at 100 min(-1) with 8-10 ventilations/min), repeated after the rescuers switched roles. The metronome provided "tock" prompts for compressions, transition prompts between compressions and ventilations, and a spoken "ventilate" prompt. During CPR with a bag/valve/mask the target compression rate of 90-110 min(-1) was achieved in 5/34 CPR sessions (15%) for the control group and 34/34 sessions (100%) for the metronome group (p<0.001). An excessive ventilation rate was not observed in either the metronome or control group during CPR with a bag/valve/mask. During CPR with a bag/endotracheal tube, the target of both a compression rate of 90-110 min(-1) and a ventilation rate of 8-11 min(-1) was achieved in 3/34 CPR sessions (9%) for the control group and 33/34 sessions (97%) for the metronome group (p<0.001). Metronome use with the secured airway scenario significantly decreased the incidence of over-ventilation (11/34 EMT pairs vs. 0/34 EMT pairs; p<0.001). A unique combination tock and voice prompting metronome was effective at directing correct chest compression and ventilation rates both before and after intubation. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

α4-Containing nicotinic receptors contribute to the effects of perinatal nicotine on ventilatory and metabolic responses of neonatal mice to ambient cooling.

PubMed

Avraam, Joanne; Cummings, Kevin J; Frappell, Peter B

2016-10-01

Among numerous studies, perinatal nicotine exposure (PN) has had variable effects on respiratory control in the neonatal period. The effects of acute nicotine exposure on breathing are largely mediated by α4-containing nicotine acetylcholine receptors (nAChRs). These receptors are also involved in thermoregulatory responses induced by both acetylcholine and nicotine. We therefore hypothesized that α4-containing nAChRs would mediate the effects of PN on the metabolic and ventilatory responses of neonates to modest cold exposure. Wild-type (WT) and α4 knockout (KO) mice were exposed to 6 mg·kg -1 ·day -1 nicotine or vehicle from embryonic day 14 At postnatal day (P) 7 mice were cooled from an ambient temperature (T A ) of 32 to 20°C. Body temperature (T B ), rate of O 2 consumption (V̇o 2 ), ventilation (V̇e), respiratory frequency (F B ), and tidal volume (V T ) were continually monitored. An absence of α4 had no effect on the metabolic response to ambient cooling. Surprisingly, PN selectively increased the metabolic response of KO pups to cooling. Regardless, KO pups became hypothermic to the same degree as WT pups, and for both genotypes the drop in T B was exacerbated by PN. PN led to hyperventilation in WT pups caused by an increase in V T , an effect that was absent in α4 KO littermates. We show that PN interacts with α4-containing nAChRs in unique ways to modulate the control of breathing and thermoregulation in the early postnatal period. Copyright © 2016 the American Physiological Society.

Relationship between arterial oxygen desaturation and ventilation during maximal exercise.

PubMed

Miyachi, M; Tabata, I

1992-12-01

The purpose of the present study was to investigate the contribution of ventilation to arterial O2 desaturation during maximal exercise. Nine untrained subjects and 22 trained long-distance runners [age 18-36 yr, maximal O2 uptake (VO2max) 48-74 ml.min-1 x kg-1] volunteered to participate in the study. The subjects performed an incremental exhaustive cycle ergometry test at 70 rpm of pedaling frequency, during which arterial O2 saturation (SaO2) and ventilatory data were collected every minute. SaO2 was estimated with a pulse oximeter. A significant positive correlation was found between SaO2 and end-tidal PO2 (PETO2; r = 0.72, r2 = 0.52, P < 0.001) during maximal exercise. These statistical results suggest that approximately 50% of the variability of SaO2 can be accounted for by differences in PETO2, which reflects alveolar PO2. Furthermore, PETO2 was highly correlated with the ventilatory equivalent for O2 (VE/VO2; r = 0.91, P < 0.001), which indicates that PETO2 could be the result of ventilation stimulated by maximal exercise. Finally, SaO2 was positively related to VE/VO2 during maximal exercise (r = 0.74, r2 = 0.55, P < 0.001). Therefore, one-half of the arterial O2 desaturation occurring during maximal exercise may be explained by less hyperventilation, specifically for our subjects, who demonstrated a wide range of trained states. Furthermore, we found an indirect positive correlation between SaO2 and ventilatory response to CO2 at rest (r = 0.45, P < 0.05), which was mediated by ventilation during maximal exercise. These data also suggest that ventilation is an important factor for arterial O2 desaturation during maximal exercise.

Effects of ischemic stroke on dynamics of cerebral autoregulation

NASA Astrophysics Data System (ADS)

Chen, Zhi; Ivanov, Plamen Ch; Hu, Kun; Stanley, Eugene; Novak, Vera

2004-03-01

Cerebral vasoregulation involves several complex mechanisms adapting blood flow to fluctuations of systemic blood pressure (BP). Autonomic BP and metabolic vasoregulation are impaired after stroke and cerebral blood flow depends on systemic BP. To probe the mechanisms of cerebral autoregulation we study levels of nonlinear synchronization between cerebral blood flow velocity (BFV) and peripheral BP. We quantify the instantaneous phase of each signal employing analytic signal approach and Hilbert transform. As a marker of synchronization, we introduce a measure of cross-correlation between the instantaneous phase increments of the BFV and BP signals at different time lags. We have studied 12 subjects with minor chronic ischemic stroke and 11 matched normotensive controls (age<65years). BFV and BP of these subjects are continuously recorded during supine baseline, head-up tilt, hyperventilation and CO2 rebreathing. For control subjects we find significant synchronization between cerebral BFV and peripheral BP only for short time lags of up to 5-6 seconds, suggesting a rapid return to a steady cerebral blood flow after initial blood pressure perturbations. In contrast, for stroke subjects BFV/BP we find enhanced synchronization over longer time lags of up to 20 seconds, suggesting entrainment of cerebral blood flow velocity by slow vasomotor rhythms. These findings suggest that cerebral vasoregulation is impaired and cerebral blood flow follows the fluctuations of systemic BP in a synchronous manner. Our analysis shows that cerebral autoregulation is impaired in 10 out of the 12 stroke subjects, which is typically difficult to diagnose with conventional methods. Thus, our novel synchronization approach offers a new tool sensitive for evaluation of changes in the dynamics of cerebral autoregulation under stroke.

Development of a clinical applicable graphical user interface to automatically detect exercise oscillatory ventilation: The VOdEX-tool.

PubMed

Cornelis, Justien; Denis, Tim; Beckers, Paul; Vrints, Christiaan; Vissers, Dirk; Goossens, Maggy

2017-08-01

Cardiopulmonary exercise testing (CPET) gained importance in the prognostic assessment of especially patients with heart failure (HF). A meaningful prognostic parameter for early mortality in HF is exercise oscillatory ventilation (EOV). This abnormal respiratory pattern is recognized by hypo- and hyperventilation during CPET. Up until now, assessment of EOV is mainly done upon visual agreement or manual calculation. The purpose of this research was to automate the interpretation of EOV so this prognostic parameter could be readily investigated during CPET. Preliminary, four definitions describing the original characteristics of EOV, were selected and integrated in the "Ventilatory Oscillations during Exercise-tool" (VOdEX-tool), a graphical user interface that allows automate calculation of EOV. A Discrete Meyer Level 2 wavelet transformation appeared to be the optimal filter to apply on the collected breath-by-breath minute ventilation CPET data. Divers aspects of the definitions i.e. cycle length, amplitude, regularity and total duration of EOV were combined and calculated. The oscillations meeting the criteria were visualised. Filter methods and cut-off criteria were made adjustable for clinical application and research. The VOdEX-tool was connected to a database. The VOdEX-tool provides the possibility to calculate EOV automatically and to present the clinician an overview of the presence of EOV at a glance. The computerized analysis of EOV can be made readily available in clinical practice by integrating the tool in the manufactures existing CPET software. The VOdEX-tool enhances assessment of EOV and therefore contributes to the estimation of prognosis in especially patients with HF. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

A Method of Managing Severe Traumatic Brain Injury in the Absence of Intracranial Pressure Monitoring: The Imaging and Clinical Examination Protocol.

PubMed

Chesnut, Randall M; Temkin, Nancy; Dikmen, Sureyya; Rondina, Carlos; Videtta, Walter; Petroni, Gustavo; Lujan, Silvia; Alanis, Victor; Falcao, Antonio; de la Fuenta, Gustavo; Gonzalez, Luis; Jibaja, Manuel; Lavarden, Arturo; Sandi, Freddy; Mérida, Roberto; Romero, Ricardo; Pridgeon, Jim; Barber, Jason; Machamer, Joan; Chaddock, Kelley

2018-01-01

The imaging and clinical examination (ICE) algorithm used in the Benchmark Evidence from South American Trials: Treatment of Intracranial Pressure (BEST TRIP) randomized controlled trial is the only prospectively investigated clinical protocol for traumatic brain injury management without intracranial pressure (ICP) monitoring. As the default literature standard, it warrants careful evaluation. We present the ICE protocol in detail and analyze the demographics, outcome, treatment intensity, frequency of intervention usage, and related adverse events in the ICE-protocol cohort. The 167 ICE protocol patients were young (median 29 years) with a median Glasgow Coma Scale motor score of 4 but with anisocoria or abnormal pupillary reactivity in 40%. This protocol produced outcomes not significantly different from those randomized to the monitor-based protocol (favorable 6-month extended Glasgow Outcome Score in 39%; 41% mortality rate). Agents commonly employed to treat suspected intracranial hypertension included low-/moderate-dose hypertonic saline (72%) and mannitol (57%), mild hyperventilation (adjusted partial pressure of carbon dioxide 30-35 mm Hg in 73%), and pressors to maintain cerebral perfusion (62%). High-dose hyperosmotics or barbiturates were uncommonly used. Adverse event incidence was low and comparable to the BEST TRIP monitored group. Although this protocol should produce similar/acceptable results under circumstances comparable to those in the trial, influences such as longer pre-hospital times and non-specialist transport personnel, plus an intensive care unit model of aggressive physician-intensive care by small groups of neurotrauma-focused intensivists, which differs from most high-resource models, support caution in expecting the same results in dissimilar settings. Finally, this protocol's ICP-titration approach to suspected intracranial hypertension (vs. crisis management for monitored ICP) warrants further study.

Treatment of Cheyne-Stokes respiration reduces arrhythmic events in chronic heart failure.

PubMed

Bitter, Thomas; Gutleben, Klaus-Jürgen; Nölker, Georg; Westerheide, Nina; Prinz, Christian; Dimitriadis, Zisis; Horstkotte, Dieter; Vogt, Jürgen; Oldenburg, Olaf

2013-10-01

This study aimed to investigate whether adequate treatment of Cheyne-Stokes respiration (CSR) reduces the risk of arrhythmic events in patients with chronic heart failure (CHF). A cohort of 403 registry patients with CHF (LVEF≤45%, NYHA-class≥2) and implanted cardioverter-defibrillator devices (ICD) was studied. They underwent overnight polygraphy, with 221 having mild or no CSR (apnea-hypopnea index [AHI]<15/h), and 182 having moderate to severe CSR (AHI>15/h). Latter ones were offered therapy with adaptive servoventilation (ASV), which 96 patients accepted and 86 rejected. During follow-up (21± 15 months) defibrillator therapies were recorded in addition to clinical and physiologic measures of heart failure severity. Event-free survival from (a) appropriate cardioverter-defibrillator therapies and (b) appropriately monitored ventricular arrhythmias was shorter in the untreated CSR group compared to the treated CSR and the no CSR group. Stepwise Cox proportional hazard regression analysis showed untreated CSR (a: hazard ratio [HR] 1.99, 95% confidence interval [CI] 1.46-2.72, P < 0.001; b: HR 2.19, 95%CI 1.42-3.37, P < 0.001), but not treated CSR (a: HR 1.06, 95%CI 0.74-1.50; P = 0.77; b: HR 1.21, 95%CI 0.75-1.93, P = 0.43) was an independent risk factor. The treated CSR group showed improvements in cardiac function and respiratory stability compared to the untreated CSR group. This study demonstrates a decrease of appropriate defibrillator therapies by ASV treated CSR in patients with CHF and ICD. A reduced exposure to hyperventilation, hypoxia, and improvement in indices of CHF severity and neurohumoral disarrangements are potential causative mechanisms. © 2013 Wiley Periodicals, Inc.

Brief ethanol exposure and stress-related factors disorganize neonatal breathing plasticity during the brain growth spurt period in the rat.

PubMed

Macchione, A F; Anunziata, F; Haymal, B O; Abate, P; Molina, J C

2018-04-01

The effects of early ethanol exposure upon neonatal respiratory plasticity have received progressive attention given a multifactorial perspective related with sudden infant death syndrome or hypoxia-associated syndromes. The present preclinical study was performed in 3-9-day-old pups, a stage in development characterized by a brain growth spurt that partially overlaps with the 3rd human gestational trimester. Breathing frequencies and apneas were examined in pups receiving vehicle or a relatively moderate ethanol dose (2.0 g/kg) utilizing a whole body plethysmograph. The experimental design also considered possible associations between drug administration stress and exteroceptive cues (plethysmographic context or an artificial odor). Ethanol exposure progressively exerted a detrimental effect upon breathing frequencies. A test conducted at PD9 when pups were under the state of sobriety confirmed ethanol's detrimental effects upon respiratory plasticity (breathing depression). Pre-exposure to the drug also resulted in a highly disorganized respiratory response following a hypoxic event, i.e., heightened apneic episodes. Associative processes involving drug administration procedures and placement in the plethysmographic context also affected respiratory plasticity. Pups that experienced intragastric administrations in close temporal contiguity with such a context showed diminished hyperventilation during hypoxia. In a 2nd test conducted at PD9 while pups were intoxicated and undergoing hypoxia, an attenuated hyperventilatory response was observed. In this test, there were also indications that prior ethanol exposure depressed breathing frequencies during hypoxia and a recovery normoxia phase. As a whole, the results demonstrated that brief ethanol experience and stress-related factors significantly disorganize respiratory patterns as well as arousal responses linked to hypoxia in neonatal rats.

Voluntary activation of the sympathetic nervous system and attenuation of the innate immune response in humans.

PubMed

Kox, Matthijs; van Eijk, Lucas T; Zwaag, Jelle; van den Wildenberg, Joanne; Sweep, Fred C G J; van der Hoeven, Johannes G; Pickkers, Peter

2014-05-20

Excessive or persistent proinflammatory cytokine production plays a central role in autoimmune diseases. Acute activation of the sympathetic nervous system attenuates the innate immune response. However, both the autonomic nervous system and innate immune system are regarded as systems that cannot be voluntarily influenced. Herein, we evaluated the effects of a training program on the autonomic nervous system and innate immune response. Healthy volunteers were randomized to either the intervention (n = 12) or control group (n = 12). Subjects in the intervention group were trained for 10 d in meditation (third eye meditation), breathing techniques (i.a., cyclic hyperventilation followed by breath retention), and exposure to cold (i.a., immersions in ice cold water). The control group was not trained. Subsequently, all subjects underwent experimental endotoxemia (i.v. administration of 2 ng/kg Escherichia coli endotoxin). In the intervention group, practicing the learned techniques resulted in intermittent respiratory alkalosis and hypoxia resulting in profoundly increased plasma epinephrine levels. In the intervention group, plasma levels of the anti-inflammatory cytokine IL-10 increased more rapidly after endotoxin administration, correlated strongly with preceding epinephrine levels, and were higher. Levels of proinflammatory mediators TNF-α, IL-6, and IL-8 were lower in the intervention group and correlated negatively with IL-10 levels. Finally, flu-like symptoms were lower in the intervention group. In conclusion, we demonstrate that voluntary activation of the sympathetic nervous system results in epinephrine release and subsequent suppression of the innate immune response in humans in vivo. These results could have important implications for the treatment of conditions associated with excessive or persistent inflammation, such as autoimmune diseases.

Bronchoconstriction induced by increasing airway temperature in ovalbumin-sensitized rats: role of tachykinins.

PubMed

Hsu, Chun-Chun; Lin, Ruei-Lung; Lin, You Shuei; Lee, Lu-Yuan

2013-09-01

This study was carried out to determine the effect of allergic inflammation on the airway response to increasing airway temperature. Our results showed the following: 1) In Brown-Norway rats actively sensitized by ovalbumin (Ova), isocapnic hyperventilation with humidified warm air (HWA) for 2 min raised tracheal temperature (Ttr) from 33.4 ± 0.6°C to 40.6 ± 0.1°C, which induced an immediate and sustained (>10 min) increase in total pulmonary resistance (Rl) from 0.128 ± 0.004 to 0.212 ± 0.013 cmH2O·ml(-1)·s (n = 6, P < 0.01). In sharp contrast, the HWA challenge caused the same increase in Ttr but did not generate any increase in Rl in control rats. 2) The increase in Rl in sensitized rats was reproducible when the same HWA challenge was repeated 60-90 min later. 3) This bronchoconstrictive effect was temperature dependent: a slightly smaller increase in peak Ttr (39.6 ± 0.2°C) generated a significant but smaller increase in Rl in sensitized rats. 4) The HWA-induced bronchoconstriction was not generated by the humidity delivered by the HWA challenge alone, because the same water content delivered by saline aerosol at room temperature had no effect. 5) The HWA-evoked increase in Rl in sensitized rats was not blocked by atropine but was completely prevented by pretreatment either with a combination of neurokinin (NK)-1 and NK-2 antagonists or with formoterol, a β2 agonist, before the HWA challenge. This study showed that increasing airway temperature evoked a pronounced and reversible increase in airway resistance in sensitized rats and that tachykinins released from the vagal bronchopulmonary C-fiber endings were primarily responsible.

Transient receptor potential melastatin 8 gene polymorphism is associated with cold-induced airway hyperresponsiveness in bronchial asthma.

PubMed

Naumov, Denis E; Perelman, Juliy M; Kolosov, Victor P; Potapova, Tatyana A; Maksimov, Vladimir N; Zhou, Xiangdong

2015-11-01

Cold-induced airway hyperresponsiveness (CAH) is common in bronchial asthma (BA) patients and represents a problem for those living in cold climate. Transient receptor potential melastatin 8 (TRPM8) channel is the main cold temperature sensor in humans that could mediate cold response in asthmatics with CAH. No associations between TRPM8 gene polymorphisms and CAH have been reported. The present study involved 123 BA patients. CAH was assessed by 3-min isocapnic (5% CO2 ) cold air (-20°C) hyperventilation challenge. The c.750G > C (rs11562975), c.1256G > A (rs7593557), c.3048C > T (rs11563208) and c.3174C > G (rs11563071) polymorphisms of TRPM8 gene were genotyped by allele-specific polymerase chain reaction (PCR) and PCR with subsequent restriction fragment length polymorphism analysis. GC genotype and C allele carriers of the c.750G > C (rs11562975) polymorphism were more frequently observed to exhibit CAH. The estimated odds ratio for the GC genotype was 3.73 95%CI (1.48; 9.37), P = 0.005. Furthermore, GC heterozygotes had a prominent decrease in forced expiratory volume in 1 s after the challenge as compared to GG homozygotes (-12% (-16; -8.1) vs -6.45% (-11; -2.1), P < 0.001). GC carriers also had a marked reduction in other spirometric parameters. The GC variant of the TRPM8:c.750G > C (rs11562975) polymorphism is associated with CAH in patients with BA, which suggests a potential role of TRPM8 in CAH development. © 2015 Asian Pacific Society of Respirology.

Monitoring in traumatic brain injury.

PubMed

Matz, P G; Pitts, L

1997-01-01

In the past several years, improvements in technology have advanced the monitoring capabilities for patients with TBI. The primary goal of monitoring the patient with TBI is to prevent secondary insults to the brain, primarily cerebral ischemia. Cerebral ischemia may occur early and without clinical correlation and portends a poor outcome. Measurement of ICP is the cornerstone of monitoring in the patient with TBI. Monitoring of ICP provides a measurement of CPP and a rough estimation of CBF. However, with alterations in pressure autoregulation, measurement of CPP does not always allow for determination of CBF. To circumvent this problem, direct measurements of CBF can be performed using clearance techniques (133Xe, N2O, Xe-CT) or invasive monitoring techniques (LDF, TDF, NIRS). Although direct and quantitative, clearance techniques do not allow for continuous monitoring. Invasive CBF monitoring techniques are new, and artifactual results can be problematic. The techniques of jugular venous saturation monitoring and TCD are well established and are powerful adjuncts to ICP monitoring. They allow the clinician to monitor cerebral oxygen extraction and blood flow velocity, respectively, for any given CPP. Use of TCD may predict posttraumatic vasospasm before clinical sequelae. Jugular venous saturation monitoring may detect clinically occult episodes of cerebral ischemia and increased oxygen extraction. Jugular venous saturation monitoring optimizes the use of hyperventilation in the treatment of intracranial hypertension. Although PET and SPECT scanning allow direct measurement of CMRO2, these techniques have limited application currently. Similarly, microdialysis is in its infancy but has demonstrated great promise for metabolic monitoring. EEG and SEP are excellent adjuncts to the monitoring arsenal and provide immediate information on current brain function. With improvements in electronic telemetry, functional monitoring by EEG or SEP may become an important part of routine monitoring in TBI.

Exercise capacity in young adults with hypertension and systolic blood pressure difference between right arm and leg after repair of coarctation of the aorta.

PubMed

Instebø, Arne; Norgård, Gunnar; Helgheim, Vegard; Røksund, Ola Drange; Segadal, Leidulf; Greve, Gottfried

2004-10-01

Coarctation of the aorta represents 5-7% of congenital heart defects. Symptoms and prognosis depend on the degree of stenosis, age at surgery, surgical method and the presence of other heart defects. Postoperative complications are hypertension, restenosis and an abnormal blood pressure response during exercise. This study includes 41 patients, 15-40 years old, operated in the period 1975-1996. All were exercised on a treadmill until maximal oxygen consumption was achieved. Blood pressure was measured in the right arm and leg before and immediately after exercise, and in the right arm during exercise. Oxygen consumption was monitored and we defined an aerobic phase, an isocapnic buffering phase and a hypocapnic hyperventilation phase. The resting systolic blood pressure correlates with the resting systolic blood pressure difference between right arm and leg. A resting systolic blood pressure difference between the right arm and leg of 0.13 kPa (1 mmHg) to 2.67 kPa (20 mmHg) corresponds with a slight increase in resting systolic blood pressure. This rise in blood pressure increases the aerobic phase of the exercise test, helping the patients to achieve higher maximal oxygen consumption. A resting systolic blood pressure difference of more than 2.67 kPa (20 mmHg) corresponds with severe hypertension and causes reduction in the aerobic phase and maximal oxygen consumption. Resting systolic blood pressure and resting systolic blood pressure difference between the right arm and leg are not indicators for blood pressure response during exercise. Exercise testing is important to reveal exercise-induced hypertension and to monitor changes in transition from aerobic to anaerobic exercise and limitation to exercise capacity.

Brazilian dentists' attitudes about medical emergencies during dental treatment.

PubMed

Arsati, Franco; Montalli, Victor Angelo; Flório, Flavia Martão; Ramacciato, Juliana Cama; da Cunha, Fernanda Lopes; Cecanho, Rodrigo; de Andrade, Eduardo Dias; Motta, Rogério Heládio Lopes

2010-06-01

The main objective of this study was to evaluate the prevalence of emergencies in dental practices and the prepared-ness and the training experience in cardiopulmonary resuscitation (CPR) of Brazilian dentists in dealing with emergencies. The volunteer participants in the study were 498 Brazilian dentists who were present at the 27th International Congress of Dentistry in São Paulo. The most prevalent emergency was presyncope (reported by 54.20 percent of respondents), followed by orthostatic hypotension (44.37 percent), moderate allergic reactions (16.86 percent), hypertensive crisis (15.06 percent), asthma (15.06 percent), syncope (12.65 percent), angina (6.82 percent), convulsion (6.22 percent), hypoglycemia (5.62 percent), hyperventilation crisis (5.22 percent), choking (2.20 percent), and cerebrovascular accident (0.8 percent). Anaphylaxis, myocardial infarction, and cardiac arrest were the rarest emergencies, reported by only 0.4, 0.2, and 0.2 percent of dentists, respectively. Only 41 percent of the dentists judged themselves capable to diagnose the cause of an emergency during a dental visit. The majority responded that they would be capable of performing initial treatment of presyncope, syncope, orthostatic hypotension, convulsion, and choking. However, most of them felt unable to treat anaphylaxis, myocardial infarction, or cardiac arrest. Further, the majority felt unable to perform CPR or undertake an intravenous injection. It was concluded that the most prevalent medical emergencies in dental practice of Brazilian dentists are presyncope and orthostatic hypotension. The occurrence of life-threatening medical emergencies like anaphylaxis, myocardial infarction, cardiac arrest, and cerebrovascular accident is rare. Brazilian dentists are not fully prepared to manage medical emergencies and have insufficient experience training in CPR.

Decreased steady-state cerebral blood flow velocity and altered dynamic cerebral autoregulation during 5-h sustained 15% O2 hypoxia.

PubMed

Nishimura, Naoko; Iwasaki, Ken-ichi; Ogawa, Yojiro; Aoki, Ken

2010-05-01

Effects of hypoxia on cerebral circulation are important for occupational, high-altitude, and aviation medicine. Increased risk of fainting might be attributable to altered cerebral circulation by hypoxia. Dynamic cerebral autoregulation is reportedly impaired immediately by mild hypoxia. However, continuous exposure to hypoxia causes hyperventilation, resulting in hypocapnia. This hypocapnia is hypothesized to restore impaired dynamic cerebral autoregulation with reduced steady-state cerebral blood flow (CBF). However, no studies have examined hourly changes in alterations of dynamic cerebral autoregulation and steady-state CBF during sustained hypoxia. We therefore examined cerebral circulation during 5-h exposure to 15% O2 hypoxia and 21% O2 in 13 healthy volunteers in a sitting position. Waveforms of blood pressure and CBF velocity in the middle cerebral artery were measured using finger plethysmography and transcranial Doppler ultrasonography. Dynamic cerebral autoregulation was assessed by spectral and transfer function analysis. As expected, steady-state CBF velocity decreased significantly from 2 to 5 h of hypoxia, accompanying 2- to 3-Torr decreases in end-tidal CO2 (ETCO2). Furthermore, transfer function gain and coherence in the very-low-frequency range increased significantly at the beginning of hypoxia, indicating impaired dynamic cerebral autoregulation. However, contrary to the proposed hypothesis, indexes of dynamic cerebral autoregulation showed no significant restoration despite ETCO2 reductions, resulting in persistent higher values of very-low-frequency power of CBF velocity variability during hypoxia (214+/-40% at 5 h of hypoxia vs. control) without significant increases in blood pressure variability. These results suggest that sustained mild hypoxia reduces steady-state CBF and continuously impairs dynamic cerebral autoregulation, implying an increased risk of shortage of oxygen supply to the brain.

Advanced airway management in hoist and longline operations in mountain HEMS - considerations in austere environments: a narrative review This review is endorsed by the International Commission for Mountain Emergency Medicine (ICAR MEDCOM).

PubMed

Pietsch, Urs; Knapp, Jürgen; Kreuzer, Oliver; Ney, Ludwig; Strapazzon, Giacomo; Lischke, Volker; Albrecht, Roland; Phillips, Patrick; Rauch, Simon

2018-04-03

Providing sufficient oxygenation and ventilation is of paramount importance for the survival of emergency patients. Therefore, advanced airway management is one of the core tasks for every rescue team. Endotracheal intubation is the gold standard to secure the airway in the prehospital setting. This review aims to highlight special considerations for advanced airway management preceding human external cargo (HEC) evacuations. We systematically searched MEDLINE, EMBASE, and PubMed in August 2017 for articles on airway management and ventilation in patients before hoist or longline operation in HEMS. Relevant reference lists were hand-searched. Three articles with regard to advanced airway management and five articles concerning the epidemiology of advanced airway management in hoist or longline rescue missions were included. We found one case report regarding ventilation during hoist operations. The exact incidence of advanced airway management before evacuation of a patient by HEC is unknown but seems to be very low (< 5%). There are several hazards which can impede mechanical ventilation of patients during HEC extractions: loss of equipment, hyperventilation, inability to ventilate and consequent hypoxia, as well as inadequacy of monitoring. Advanced airway management prior to HEC operation is rarely performed. If intubation before helicopter hoist operations (HHO) and human cargo sling (HCS) extraction is considered by the rescue team, a risk/benefit analysis should be performed and a clear standard operating procedure (SOP) should be defined. Continuous and rigorous training including the whole crew is required. An international registry on airway management during HEC extraction would be desirable.

Specific cerebral heat shock proteins and histamine receptor cross-talking mechanisms promote distinct lead-dependent neurotoxic responses in teleosts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giusi, Giuseppina; Alo, Raffaella; Crudo, Michele

Recent interests are beginning to be directed towards toxic neurobiological dysfunctions caused by lead (Pb) in aquatic vertebrates. In the present work, treatment with a maximum acceptable toxic concentration of this heavy metal was responsible for highly significant (p < 0.01) abnormal motor behaviors such as hyperactive movements in the teleost Thalassoma pavo and the same treatment accounted for significantly (p < 0.05) enhanced hyperventilating states. On the other hand, greater abnormal motor behaviors were detected in the presence of the histamine (HA) receptor subtype 2 (H{sub 2}R) antagonist cimetidine (Cim), as shown by the very robust (p < 0.001)more » increases of the two behavioral states. Interestingly, elevated expression levels of stress-related factors, i.e. heat shock protein70/90 (HSP90/70) orthologs were reported for the first time in hypothalamic and mesencephalic areas of Pb-treated teleosts. In particular, an up-regulation of HSP70 was readily detected when this heavy metal was given concomitantly with Cim, while the histamine subtype 3 antagonist (H{sub 3}R) thioperamide (Thio), instead, blocked Pb-dependent up-regulatory trends of both chaperones in mostly hypothalamic areas. Moreover, intense neuronal damages of the above brain regions coincided with altered expressions of HSP70 and HSP90 when treated only with Cim. Overall these first results show that distinct H{sub n}R are able to exert a net neuroprotective role arising from their interaction with chaperones in fish exposed to Pb-dependent stressful conditions making this a potentially key interaction especially for T. pavo, aquatic species which plays an important ecological role towards the survival of other commercially vital fishes.« less

Brain Abscess.

PubMed

Davis; Baldwin

1999-05-01

Optimal treatment of a brain abscess requires early clinical suspicion, and the diagnosis is usually made by identification of the abscess on contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI). The immediate first step is to reduce the potentially life-threatening brain mass (abscess and surrounding cerebral edema) and secure the diagnosis with culture specimens. This is usually accomplished by reducing the increased intracranial pressure (ICP) through surgical aspiration with or without drainage of the abscess pus. The surgical procedure chosen depends on several factors, including the location and type of abscess, multiplicity, and the medical condition of the patient. In addition, dexamethasone and hyperventilation may be required if brain herniation is imminent. The dexamethasone dose should be reduced as soon as the ICP is reduced because steroid administration may retard abscess capsule formation and decrease antibiotic concentrations within the abscess cavity. Antibiotic therapy should be started as soon as the diagnosis is made. Penicillin G or third-generation cephalosporins plus metronidazole are commonly given to treat both anaerobic and aerobic bacteria. The initial choice of antibiotic will vary on the basis of the suspected source of the brain organisms, which is most often either contiguous spread from a sinus or mastoid infection or hematogenous spread from a pulmonary, gastrointestinal, cardiac, or dental infection. Isolation and determination of the antibiotic sensitivities of the organism from abscess pus allow definitive antibiotic therapy. Patients should be managed in an intensive care unit. Phenytoin is often given to prevent seizures, which could further elevate the ICP. The duration of antimicrobial treatment is 4 to 8 weeks, during which time the patient should be monitored clinically and with repeated neuroimaging studies to ensure abscess resolution.