A new device for administration of continuous positive airway pressure in preterm infants: comparison with a standard nasal CPAP continuous positive airway pressure system.

PubMed

Trevisanuto, Daniele; Grazzina, Nicoletta; Doglioni, Nicoletta; Ferrarese, Paola; Marzari, Francesco; Zanardo, Vincenzo

2005-06-01

We compared the effectiveness of a new continuous positive airway pressure (CPAP) device (neonatal helmet CPAP) with a conventional nasal CPAP system in preterm neonates needing continuous distending pressure. Randomized, physiological, cross-over study in a tertiary referral, neonatal intensive care unit in a university teaching hospital. Twenty very low birth weight infants with a postnatal age greater than 24 h who were receiving nasal CPAP for apnea and/or mild respiratory distress were enrolled. CPAP delivered by neonatal helmet CPAP and nasal CPAP in random order for two subsequent 90-min periods. Were continuously measured the Neonatal Infant Pain Scale (NIPS) score, oxygen requirements, respiratory rate, heart rate, oxygen saturation, transcutaneous PO(2) (tcPO(2)) and PCO(2) (tcPCO(2)), blood pressure, and desaturations. NIPS scores were significantly lower when the infants were on the neonatal helmet CPAP than when they were on nasal CPAP (0.26+/-0.07 vs. 0.63+/-0.12). The other studied parameters did not differ between the two CPAP modes. The number of desaturations was reduced during the neonatal helmet CPAP treatment (18 vs. 32), although this difference was not significant. In this short-term physiological study the neonatal helmet CPAP appears to be as good as the golden standard for managing preterm infants needing continuous distending pressure, with enhanced tolerability. Further evaluation in a randomized clinical trial is needed to confirm these findings.

The Supraglottic Effect of a Reduction in Expiratory Mask Pressure During Continuous Positive Airway Pressure

PubMed Central

Masdeu, Maria J.; Patel, Amit V.; Seelall, Vijay; Rapoport, David M.; Ayappa, Indu

2012-01-01

Study Objectives: Patients with obstructive sleep apnea may have difficulty exhaling against positive pressure, hence limiting their acceptance of continuous positive airway pressure (CPAP). C-Flex is designed to improve comfort by reducing pressure in the mask during expiration proportionally to expiratory airflow (3 settings correspond to increasing pressure changes). When patients use CPAP, nasal resistance determines how much higher supraglottic pressure is than mask pressure. We hypothesized that increased nasal resistance results in increased expiratory supraglottic pressure swings that could be mitigated by the effects of C-Flex on mask pressure. Design: Cohort study. Setting: Sleep center. Participants: Seventeen patients with obstructive sleep apnea/hypopnea syndrome and a mechanical model of the upper airway. Interventions: In patients on fixed CPAP, CPAP with different C-Flex levels was applied multiple times during the night. In the model, 2 different respiratory patterns and resistances were tested. Measurements and Results: Airflow, expiratory mask, and supraglottic pressures were measured on CPAP and on C-Flex. Swings in pressure during expiration were determined. On CPAP, higher nasal resistance produced greater expiratory pressure swings in the supraglottis in the patients and in the model, as expected. C-Flex 3 produced expiratory drops in mask pressure (range −0.03 to −2.49 cm H2O) but mitigated the expira-tory pressure rise in the supraglottis only during a sinusoidal respiratory pattern in the model. Conclusions: Expiratory changes in mask pressure induced by C-Flex did not uniformly transmit to the supraglottis in either patients with obstructive sleep apnea on CPAP or in a mechanical model of the upper airway with fixed resistance. Data suggest that the observed lack of expiratory drop in supraglottic pressure swings is related to dynamics of the C-Flex algorithm. Citation: Masdeu MJ; Patel AV; Seelall V; Rapoport DM; Ayappa I. The supraglottic effect of a reduction in expiratory mask pressure during continuous positive airway pressure. SLEEP 2012;35(2):263-272. PMID:22294817

Continuous Positive Airway Pressure Versus Oxygen Therapy in the Cardiac Surgical Ward: A Randomized Trial.

PubMed

Olper, Luigi; Bignami, Elena; Di Prima, Ambra L; Albini, Santina; Nascimbene, Simona; Cabrini, Luca; Landoni, Giovanni; Alfieri, Ottavio

2017-02-01

Noninvasive ventilation (NIV) is a common technique to manage patients with acute respiratory failure in the intensive care unit. However, use of NIV in general wards is less well described. The authors' aim was to demonstrate efficacy of NIV, applied in a cardiac surgery ward, in improving oxygenation in patients who developed hypoxemic acute respiratory failure after being discharged from the intensive care unit. Randomized, open-label trial. University hospital. Sixty-four patients with hypoxemia (PaO 2 /F I O 2 ratio between 100 and 250) admitted to the main ward after cardiac surgery. Patients were randomized to receive standard treatment (oxygen, early mobilization, a program of breathing exercises and diuretics) or continuous positive airway pressure in addition to standard treatment. Continuous positive airway pressure was administered 3 times a day for 2 consecutive days. Every cycle lasted 1 to 3 hours. All patients completed their 1-year follow-up. Data were analyzed according to the intention-to-treat principle. The primary endpoint was the number of patients with PaO 2 /F I O 2 <200 48 hours after randomization. Continuous positive airway pressure use was associated with a statistically significant reduction in the number of patients with PaO 2 /F I O 2 <200 (4/33 [12%] v 14/31 [45%], p = 0.003). One patient in the control group died at the 30-day follow-up. Among patients with acute respiratory failure following cardiac surgery, administration of continuous positive airway pressure in the main ward was associated with improved respiratory outcome. This was the first study that was performed in the main ward of post-surgical patients with acute respiratory failure. Copyright © 2017 Elsevier Inc. All rights reserved.

Continuous long-term measurements of the middle ear pressure in subjects without a history of ear disease.

PubMed

Tideholm, B; Carlborg, B; Jönsson, S; Bylander-Groth, A

1998-06-01

A new method was used for continuous measurement of the middle ear (ME) pressure during a 24-h period. In 10 subjects without a history of ear disease a small perforation was made through the tympanic membrane. A tight rubber stopper containing a small polyethylene tube was fitted into the external ear canal. Conventional tubal function tests were performed. The equipment was then carried by the subjects for 24 h of normal activity to monitor any slow or rapid dynamic pressure change in the ME. Body position was found to be the most important factor affecting ME pressure variation, during the 24-h continuous pressure measurements. A significant pressure rise occurred in the recumbent position in all but one subject. Few rapid pressure equilibrations were seen during the recordings, indicating few tubal openings. This implies that the pressure changes in the ME seen in this study were mainly the result of gas exchange over the mucosa. The investigation might be a base for reference when investigating different kinds of pathologic conditions in the ear.

Continuous Negative Abdominal Pressure Reduces Ventilator-induced Lung Injury in a Porcine Model.

PubMed

Yoshida, Takeshi; Engelberts, Doreen; Otulakowski, Gail; Katira, Bhushan; Post, Martin; Ferguson, Niall D; Brochard, Laurent; Amato, Marcelo B P; Kavanagh, Brian P

2018-04-27

In supine patients with acute respiratory distress syndrome, the lung typically partitions into regions of dorsal atelectasis and ventral aeration ("baby lung"). Positive airway pressure is often used to recruit atelectasis, but often overinflates ventral (already aerated) regions. A novel approach to selective recruitment of dorsal atelectasis is by "continuous negative abdominal pressure." A randomized laboratory study was performed in anesthetized pigs. Lung injury was induced by surfactant lavage followed by 1 h of injurious mechanical ventilation. Randomization (five pigs in each group) was to positive end-expiratory pressure (PEEP) alone or PEEP with continuous negative abdominal pressure (-5 cm H2O via a plexiglass chamber enclosing hindlimbs, pelvis, and abdomen), followed by 4 h of injurious ventilation (high tidal volume, 20 ml/kg; low expiratory transpulmonary pressure, -3 cm H2O). The level of PEEP at the start was ≈7 (vs. ≈3) cm H2O in the PEEP (vs. PEEP plus continuous negative abdominal pressure) groups. Esophageal pressure, hemodynamics, and electrical impedance tomography were recorded, and injury determined by lung wet/dry weight ratio and interleukin-6 expression. All animals survived, but cardiac output was decreased in the PEEP group. Addition of continuous negative abdominal pressure to PEEP resulted in greater oxygenation (PaO2/fractional inspired oxygen 316 ± 134 vs. 80 ± 24 mmHg at 4 h, P = 0.005), compliance (14.2 ± 3.0 vs. 10.3 ± 2.2 ml/cm H2O, P = 0.049), and homogeneity of ventilation, with less pulmonary edema (≈10% less) and interleukin-6 expression (≈30% less). Continuous negative abdominal pressure added to PEEP reduces ventilator-induced lung injury in a pig model compared with PEEP alone, despite targeting identical expiratory transpulmonary pressure.

Lung mechanical and vascular changes during positive- and negative-pressure lung inflations: importance of reference pressures in the pulmonary vasculature.

PubMed

Peták, Ferenc; Albu, Gergely; Lele, Enikö; Hantos, Zoltán; Morel, Denis R; Fontao, Fabienne; Habre, Walid

2009-03-01

The continuous changes in lung mechanics were related to those in pulmonary vascular resistance (Rv) during lung inflations to clarify the mechanical changes in the bronchoalveolar system and the pulmonary vasculature. Rv and low-frequency lung impedance data (Zl) were measured continuously in isolated, perfused rat lungs during 2-min inflation-deflation maneuvers between transpulmonary pressures of 2.5 and 22 cmH(2)O, both by applying positive pressure at the trachea and by generating negative pressure around the lungs in a closed box. ZL was averaged and evaluated for 2-s time windows; airway resistance (Raw), parenchymal damping and elastance (H) were determined in each window. Lung inflation with positive and negative pressures led to very similar changes in lung mechanics, with maximum decreases in Raw [-68 +/- 4 (SE) vs. -64 +/- 18%] and maximum increases in H (379 +/- 36 vs. 348 +/- 37%). Rv, however, increased with positive inflation pressure (15 +/- 1%), whereas it exhibited mild decreases during negative-pressure expansions (-3 +/- 0.3%). These results demonstrate that pulmonary mechanical changes are not affected by the opposing modes of lung inflations and confirm the importance of relating the pulmonary vascular pressures in interpreting changes in Rv.

Hemodynamic effects of external continuous negative pressure ventilation compared with those of continuous positive pressure ventilation in dogs with acute lung injury.

PubMed

Skaburskis, M; Helal, R; Zidulka, A

1987-10-01

Patients with noncardiogenic pulmonary edema requiring ventilatory assistance are usually supported with CPPV using positive end-expiratory pressure (PEEP), but CPPV requires endotracheal intubation and may decrease cardiac output (QT). The purpose of this study was to examine thoracoabdominal continuous negative pressure ventilation (CNPV) using external negative end-expiratory pressure (NEEP). The effects on gas exchange and hemodynamics were compared with those of CPPV with PEEP, with the premise that CNPV might sustain venous return and improve QT. In 6 supine, anesthetized and paralyzed dogs with oleic-acid-induced pulmonary edema, 30 min of CNPV was alternated twice with 30 min of CPPV. Positive and negative pressure ventilation were carefully matched for fractional inspired oxygen concentration (FIO2 = 0.56), breathing frequency, and tidal volume. In addition, we matched the increase in delta FRC obtained with the constant distending pressures produced by both modes of ventilation. An average of -9 cm H2O of NEEP produced the same delta FRC as 10.8 cm H2O of PEEP. Gas exchange did not differ significantly between the 2 modes. However, QT was 15.8% higher during CNPV than during CPPV (p less than 0.02). Mixed venous oxygen saturation also improved during CNPV compared with that during CPPV (58.3 versus 54.5%, p less than 0.01). Negative pressure ventilation using NEEP may be a viable alternative to positive pressure ventilation with PEEP in the management of critically ill patients with noncardiogenic pulmonary edema. It offers comparable improvement in gas exchange with the advantages of less cardiac depression and the possible avoidance of endotracheal intubation.

Characteristics of the mach disk in the underexpanded jet in which the back pressure continuously changes with time

NASA Astrophysics Data System (ADS)

Irie, T.; Yasunobu, T.; Kashimura, H.; Setoguchi, T.

2003-05-01

When the high-pressure gas is exhausted to the vacuum chamber from the nozzle, the underexpanded supersonic jet contained with the Mach disk is generally formed. The eventual purpose of this study is to clarify the unsteady phenomenon of the underexpanded free jet when the back pressure continuously changes with time. The characteristic of the Mach disk has been clarified in consideration of the diameter and position of it by the numerical analysis in this paper. The sonic jet of the exit Mach number Me=1 is assumed and the axisymmetric conservational equation is solved by the TVD method in the numerical calculation. The diameter and position of the Mach disk differs with the results of a steady jet and the influence on the continuously changing of the back pressure is evidenced from the comparison with the case of steady supersonic jet.

Strategies to Sustain and Enhance Performance in Stressful Environments

DTIC Science & Technology

1990-03-14

Pressure Switch in his left hand which controlled power to the vacuum source which was only active when the subject was pressing on the Page 6 positive... pressure switch . Internal LBNP chamber vacuum was calibrated with a Wallace & Tierman 1500 Hi-Performance Gauge (Model 61A-1D-0800, Wallace & Tierman...pressure release when the subject released the positive pressure switch without warning. Behavioral testing continued regardless of when LBNP was returned to

Oxidative stress and quality of life in elderly patients with obstructive sleep apnea syndrome: are there differences after six months of Continuous Positive Airway Pressure treatment?

PubMed Central

Yagihara, Fabiana; Lucchesi, Ligia Mendonça; D'Almeida, Vânia; de Mello, Marco Túlio; Tufik, Sergio; Bittencourt, Lia Rita Azeredo

2012-01-01

OBJECTIVES: This study evaluated the effect of Continuous Positive Airway Pressure treatment on oxidative stress parameters and the quality of life of elderly patients with obstructive sleep apnea syndrome. METHODS: In total, 30 obstructive sleep apnea syndrome patients and 27 subjects without obstructive sleep apnea syndrome were included in this study. Both groups underwent quality of life and oxidative stress evaluations at baseline and after six months. Polysomnography was performed in both groups at baseline and a second time in the obstructive sleep apnea syndrome group after six months of Continuous Positive Airway Pressure treatment. All of the variables were compared between the control and obstructive sleep apnea syndrome groups in this prospective case-control study. RESULTS: The baseline concentrations of the antioxidant enzyme catalase were higher in the obstructive sleep apnea syndrome group than the control group. After Continuous Positive Airway Pressure treatment, the obstructive sleep apnea syndrome group exhibited a reduction in the level of oxidative stress, as indicated by a decrease in the level of lipid peroxidation measured by the malondialdehyde (MDA) concentration [pre: 2.7 nmol malondialdehyde/mL (95% 1.6-3.7) vs. post: 1.3 nmol MDA/mL (0.7-1.9), p<0.01]. Additionally, improvements were observed in two domains covered by the SF-36 questionnaire: functional capacity [pre: 77.4 (69.2-85.5) vs. post: 83.4 (76.9-89.9), p = 0.002] and pain [pre: 65.4 (52.8-78.1) vs. post: 77.8 (67.2-88.3), p = 0.004]. CONCLUSION: Our study demonstrated that the use of Continuous Positive Airway Pressure to treat obstructive sleep apnea syndrome in elderly patients reduced oxidative stress and improved the quality of life. PMID:22760893

Nonlinear aspects of infrasonic pressure transfer into the perilymph.

PubMed

Krukowski, B; Carlborg, B; Densert, O

1980-06-01

The perilymphatic pressure was studied in response to various low frequency pressure changes in the ear canal. The pressure transfer was analysed and found to be nonlinear in many aspects. The pressure response was found to contain two time constants representing the inner ear pressure regulating mechanisms. The time constants showed an asymmetry in response to positive and negative going inputs--the effects to some extent proportional to input levels. Further nonlinearities were found when infrasonic sine waves were applied to the ear. Harmonic distortion and modulation appeared. When short bursts of infrasound were introduced a clear d.c. shift was observed as a consequence of an asymmetry in the response to positive and negative going pressure inputs. A temporary change in mean perilymphatic pressure was thus achieved and continued throughout the duration of the signal. At very low frequencies a distinct phase shift was detected in the sine waves. This appeared as a phase lead, breaking the continuity of the output sine wave.

Evaluation of Time to Donor Lenticule Apposition Using Intraoperative Optical Coherence Tomography in Descemet Stripping Automated Endothelial Keratoplasty.

PubMed

Titiyal, Jeewan S; Kaur, Manpreet; Falera, Ruchita; Jose, Cijin P; Sharma, Namrata

2016-04-01

To evaluate the time to donor lenticule apposition in cases of Descemet stripping automated endothelial keratoplasty (DSAEK) using microscope-integrated intraoperative optical coherence tomography (iOCT). Thirty eyes of 27 patients planned to undergo Descemet stripping automated endothelial keratoplasty were enrolled in this prospective study. In group I (n = 10), continuous intracameral positive pressure was maintained for 8 minutes. In group II (n = 10) and group III (n = 10), external corneal massage was initiated simultaneously with positive intracameral air pressure. The external corneal massage was continued till complete resolution of interface fluid; the positive intracameral pressure was maintained for 8 minutes in group II and for 5 minutes in group III. The host-donor relationship was continuously monitored with the iOCT. The main outcome measure was time to complete donor lenticule apposition. In group I, the interface fluid persisted after 8 minutes of positive intracameral pressure in all eyes (10/10); hence an external corneal massage was required to achieve optimal donor adherence. In groups II and III, all eyes (20/20) had complete resolution of the interface fluid at the end of 3 minutes. In 100% of the eyes (30/30), the grafts were attached after anterior chamber decompression as seen on the iOCT. In all cases, the donor lenticules were adhered in the postoperative period. iOCT helps in understanding that the donor lenticule is well apposed within 1 to 3 minutes with the technique of simultaneous positive intracameral pressure and external corneal massage. This knowledge minimizes the waiting time for graft apposition and prevents prolonged intraocular pressure elevation.

40 CFR 147.3107 - Mechanical integrity.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Oklahoma Indian Tribes § 147.3107 Mechanical integrity. (a) Monitoring of annulus pressure conducted pursuant to § 146.8(b)(1) shall be preceded by an initial pressure test. A positive gauge pressure on the casing/tubing annulus (filled with liquid) shall be maintained continuously. The pressure shall be...

40 CFR 147.3107 - Mechanical integrity.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Oklahoma Indian Tribes § 147.3107 Mechanical integrity. (a) Monitoring of annulus pressure conducted pursuant to § 146.8(b)(1) shall be preceded by an initial pressure test. A positive gauge pressure on the casing/tubing annulus (filled with liquid) shall be maintained continuously. The pressure shall be...

40 CFR 147.3107 - Mechanical integrity.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Oklahoma Indian Tribes § 147.3107 Mechanical integrity. (a) Monitoring of annulus pressure conducted pursuant to § 146.8(b)(1) shall be preceded by an initial pressure test. A positive gauge pressure on the casing/tubing annulus (filled with liquid) shall be maintained continuously. The pressure shall be...

40 CFR 147.3107 - Mechanical integrity.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Oklahoma Indian Tribes § 147.3107 Mechanical integrity. (a) Monitoring of annulus pressure conducted pursuant to § 146.8(b)(1) shall be preceded by an initial pressure test. A positive gauge pressure on the casing/tubing annulus (filled with liquid) shall be maintained continuously. The pressure shall be...

Prolonged lateral steep position impairs respiratory mechanics during continuous lateral rotation therapy in respiratory failure.

PubMed

Schellongowski, Peter; Losert, Heidrun; Locker, Gottfried J; Laczika, Klaus; Frass, Michael; Holzinger, Ulrike; Bojic, Andja; Staudinger, Thomas

2007-04-01

To establish whether prolonged lateral steep position during continuous rotation therapy leads to improvement on pulmonary gas exchange, respiratory mechanics and hemodynamics. Prospective observational study. Intensive care unit of a university hospital. Twelve consecutive patients suffering from acute lung injury or adult respiratory distress syndrome undergoing continuous rotation therapy. Blood gas analysis, static lung compliance, blood pressure, cardiac index and pulmonary shunt fraction were measured in supine as well as in left and right lateral steep position at 62 degrees during continuous rotation therapy (phase I). Rotation was then stopped for 30 min with the patients in supine position, left and right lateral steep position, and the same measurements were performed every 10 min (phase II). Phase I and II revealed no significant changes in PaO(2)/FiO(2) ratio, mean arterial blood pressure, pulmonary shunt fraction, or cardiac index. Significantly lower static compliance was observed in lateral steep position than in supine position (p<0.001). Concomitantly, PaCO(2) was significantly lower in supine position than in left and right lateral steep position (p<0.01). Lateral steep positioning impairs the compliance of the respiratory system. Prolonged lateral steep position does not lead to benefits with respect to oxygenation or hemodynamics. Individual response to the different positions is unpredictable. The pauses in "extreme" positions should be as short as possible.

Effects of continuous positive airway pressure on blood pressure in patients with resistant hypertension and obstructive sleep apnea: a systematic review and meta-analysis of six randomized controlled trials

PubMed Central

Lei, Qiang; Lv, Yunhui; Li, Kai; Ma, Lei; Du, Guodong; Xiang, Yan; Li, Xuqing

2017-01-01

ABSTRACT Objective: To evaluate systematically the effects of continuous positive airway pressure (CPAP) on blood pressure in patients with resistant hypertension and obstructive sleep apnea (OSA). Methods: The Cochrane Library, PubMed, ScienceDirect, and the Web of Science were searched for studies investigating the effects of CPAP on blood pressure in patients with resistant hypertension and OSA. The selected studies underwent quality assessment and meta-analysis, as well as being tested for heterogeneity. Results: Six randomized controlled trials were included in the meta-analysis. The pooled estimates of the changes in mean systolic blood pressure and mean diastolic blood pressure (as assessed by 24-h ambulatory blood pressure monitoring) were −5.40 mmHg (95% CI: −9.17 to −1.64; p = 0.001; I2 = 74%) and −3.86 mmHg (95% CI: −6.41 to −1.30; p = 0.00001; I2 = 79%), respectively. Conclusions: CPAP therapy can significantly reduce blood pressure in patients with resistant hypertension and OSA. PMID:28767770

Cardiopulmonary Responses to Pressure Breathing.

DTIC Science & Technology

1995-05-01

possible improvement in VAIQ relationships, at least in lowV a/Q regions or shunt. This is equivalent to continuous positive airway pressure ( CPAP ) used clinically to augment arterial oxygenation in patients.

Cardiorespiratory interaction with continuous positive airway pressure

PubMed Central

Bonafini, Sara; Fava, Cristiano; Steier, Joerg

2018-01-01

The treatment of choice for obstructive sleep apnoea (OSA) is continuous positive airway pressure therapy (CPAP). Since its introduction in clinical practice, CPAP has been used in various clinical conditions with variable and heterogeneous outcomes. In addition to the well-known effects on the upper airway CPAP impacts on intrathoracic pressures, haemodynamics and blood pressure (BP) control. However, short- and long-term effects of CPAP therapy depend on multiple variables which include symptoms, underlying condition, pressure used, treatment acceptance, compliance and usage. CPAP can alter long-term cardiovascular risk in patients with cardiorespiratory conditions. Furthermore, the effect of CPAP on the awake patient differs from the effect on the patients while asleep, and this might contribute to discomfort and removal of the use interface. The purpose of this review is to highlight the physiological impact of CPAP on the cardiorespiratory system, including short-term benefits and long-term outcomes. PMID:29445529

Adult obstructive sleep apnoea

PubMed Central

Jordan, Amy S.; McSharry, David G.; Malhotra, Atul

2013-01-01

Obstructive sleep apnoea is an increasingly common disorder of repeated upper airway collapse during sleep, which leads to oxygen desaturation and disrupted sleep. Symptoms include snoring, witnessed apnoeas, and sleepiness. Pathogenesis varies; predisposing factors include small upper airway lumen, unstable respiratory control, low arousal threshold, small lung volume, and dysfunctional upper airway dilator muscles. Risk factors include obesity, male sex, age, menopause, fluid retention, adenotonsillar hypertrophy, and smoking. Obstructive sleep apnoea causes sleepiness, road traffic accidents, and probably systemic hypertension. It has also been linked to myocardial infarction, congestive heart failure, stroke, and diabetes mellitus though not definitively. Continuous positive airway pressure is the treatment of choice, with adherence of 60–70%. Bi-level positive airway pressure or adaptive servo-ventilation can be used for patients who are intolerant to continuous positive airway pressure. Other treatments include dental devices, surgery, and weight loss. PMID:23910433

Choosing an Oronasal Mask to Deliver Continuous Positive Airway Pressure May Cause More Upper Airway Obstruction or Lead to Higher Continuous Positive Airway Pressure Requirements than a Nasal Mask in Some Patients: A Case Series

PubMed Central

Ng, Justin R.; Aiyappan, Vinod; Mercer, Jeremy; Catcheside, Peter G.; Chai-Coetzer, Ching Li; McEvoy, R. Doug; Antic, Nick

2016-01-01

Study Objectives: The choice of mask interface used with continuous positive airway pressure (CPAP) therapy can affect the control of upper airway obstruction (UAO) in obstructive sleep apnea (OSA). We describe a case series of four patients with paradoxical worsening of UAO with an oronasal mask and the effect of changing to a nasal mask. Methods: We retrospectively reviewed the case histories of 4 patients and recorded patient demographics, in-laboratory and ambulatory CPAP titration data, CPAP therapy data, type of mask interface used and potential confounding factors. Results: The 4 cases (mean ± SD: age = 59 ± 16 y; BMI = 30.5 ± 4.5 kg/m2) had a high residual apnoea-hypopnea index (AHI) (43 ± 14.2 events/h) and high CPAP pressure requirements (14.9 ± 6.6 cmH2O) with an oronasal mask. Changing to a nasal mask allowed adequate control of UAO with a significant reduction in the average residual AHI (3.1 ± 1.5 events/h). In two of the four cases, it was demonstrated that control of UAO was obtained at a much lower CPAP pressure compared to the oronasal mask (Case one = 17.5 cmH2O vs 12cmH2O; Case two = 17.9 cmH2O vs 7.8 cmH2O). Other potential confounding factors were unchanged. There are various physiological observations that may explain these findings but it is uncertain which individuals are susceptible to these mechanisms. Conclusions: If patients have OSA incompletely controlled by CPAP with evidence of residual UAO and/or are requiring surprisingly high CPAP pressure to control OSA with an oronasal mask, the choice of mask should be reviewed and consideration be given to a trial of a nasal mask. Commentary: A commentary on this article appears in this issue on page 1209. Citation: Ng JR, Aiyappan V, Mercer J, Catcheside PG, Chai-Coetzer CL, McEvoy RD, Antic N. Choosing an oronasal mask to deliver continuous positive airway pressure may cause more upper airway obstruction or lead to higher continuous positive airway pressure requirements than a nasal mask in some patients: a case series. J Clin Sleep Med 2016;12(9):1227–1232. PMID:27306398

Blood Pressure Associates with Standing Balance in Elderly Outpatients

PubMed Central

Pasma, Jantsje H.; Bijlsma, Astrid Y.; Klip, Janneke M.; Stijntjes, Marjon; Blauw, Gerard Jan; Muller, Majon; Meskers, Carel G. M.; Maier, Andrea B.

2014-01-01

Objectives Assessment of the association of blood pressure measurements in supine and standing position after a postural change, as a proxy for blood pressure regulation, with standing balance in a clinically relevant cohort of elderly, is of special interest as blood pressure may be important to identify patients at risk of having impaired standing balance in routine geriatric assessment. Materials and Methods In a cross-sectional cohort study, 197 community-dwelling elderly referred to a geriatric outpatient clinic of a middle-sized teaching hospital were included. Blood pressure was measured intermittently (n = 197) and continuously (subsample, n = 58) before and after a controlled postural change from supine to standing position. The ability to maintain standing balance was assessed during ten seconds of side-by-side, semi-tandem and tandem stance, with both eyes open and eyes closed. Self-reported impaired standing balance and history of falls were recorded by questionnaires. Logistic regression analyses were used to examine the association between blood pressure and 1) the ability to maintain standing balance; 2) self-reported impaired standing balance; and 3) history of falls, adjusted for age and sex. Results Blood pressure decrease after postural change, measured continuously, was associated with reduced ability to maintain standing balance in semi-tandem stance with eyes closed and with increased self-reported impaired standing balance and falls. Presence of orthostatic hypotension was associated with reduced ability to maintain standing balance in semi-tandem stance with eyes closed for both intermittent and continuous measurements and with increased self-reported impaired standing balance for continuous measurements. Conclusion Continuous blood pressure measurements are of additional value to identify patients at risk of having impaired standing balance and may therefore be useful in routine geriatric care. PMID:25222275

Continuous Positive Airway Pressure During Exercise Improves Walking Time in Patients Undergoing Inpatient Cardiac Rehabilitation After Coronary Artery Bypass Graft Surgery: A RANDOMIZED CONTROLLED TRIAL.

PubMed

Pantoni, Camila Bianca Falasco; Di Thommazo-Luporini, Luciana; Mendes, Renata Gonçalves; Caruso, Flávia Cristina Rossi; Mezzalira, Daniel; Arena, Ross; Amaral-Neto, Othon; Catai, Aparecida Maria; Borghi-Silva, Audrey

2016-01-01

Continuous positive airway pressure (CPAP) has been used as an effective support to decrease the negative pulmonary effects of coronary artery bypass graft (CABG) surgery. However, it is unknown whether CPAP can positively influence patients undergoing CABG during exercise. This study evaluated the effectiveness of CPAP on the first day of ambulation after CABG in patients undergoing inpatient cardiac rehabilitation (CR). Fifty-four patients after CABG surgery were randomly assigned to receive either inpatient CR and CPAP (CPG) or standard CR without CPAP (CG). Cardiac rehabilitation included walking and CPAP pressures were set between 10 to 12 cmH2O. Participants were assessed on the first day of walking at rest and during walking. Outcome measures included breathing pattern variables, exercise time in seconds (ETs), dyspnea/leg effort ratings, and peripheral oxygen saturation (SpO2). Twenty-seven patients (13 CPG vs 14 CG) completed the study. Compared with walking without noninvasive ventilation assistance, CPAP increased ETs by 43.4 seconds (P = .040) during walking, promoted better thoracoabdominal coordination, increased ventilation during walking by 12.5 L/min (P = .001), increased SpO2 values at the end of walking by 2.6% (P = .016), and reduced dyspnea ratings by 1 point (P = .008). Continuous positive airway pressure can positively influence exercise tolerance, ventilatory function, and breathing pattern in response to a single bout of exercise after CABG.

Nasal CPAP and preterm bradycardia: cause or cure.

PubMed

MacLaren, Andrew Torrance; Peters, Colin; MacDonald, Peter D

2014-05-23

Nasal continuous positive airway pressure (nCPAP) is widely used for the treatment of respiratory distress syndrome and apnoea of prematurity. Complications related to fixation devices have been well documented. We report a clinically well preterm baby suffering intermittent, profound episodes of bradycardia without any prior associated apnoea or desaturation. We believe these episodes were due to the oculocardiac reflex related to orbital compression from the continuous positive airway pressure (CPAP) fixation straps. Bradycardia was replicated by gentle ocular compression and the episodes resolved after repositioning the CPAP straps. Vagal overstimulation has previously been reported in preterm babies but we believe this to be the first case in which pressure from CPAP strapping has been reported to trigger bradycardia. However, we suspect that similar cases could easily go unrecognised. Careful positioning of CPAP securing straps may prevent accidental vagal overstimulation contributing to episodic bradycardia. 2014 BMJ Publishing Group Ltd.

Adult obstructive sleep apnoea.

PubMed

Jordan, Amy S; McSharry, David G; Malhotra, Atul

2014-02-22

Obstructive sleep apnoea is an increasingly common disorder of repeated upper airway collapse during sleep, leading to oxygen desaturation and disrupted sleep. Features include snoring, witnessed apnoeas, and sleepiness. Pathogenesis varies; predisposing factors include small upper airway lumen, unstable respiratory control, low arousal threshold, small lung volume, and dysfunctional upper airway dilator muscles. Risk factors include obesity, male sex, age, menopause, fluid retention, adenotonsillar hypertrophy, and smoking. Obstructive sleep apnoea causes sleepiness, road traffic accidents, and probably systemic hypertension. It has also been linked to myocardial infarction, congestive heart failure, stroke, and diabetes mellitus though not definitively. Continuous positive airway pressure is the treatment of choice, with adherence of 60-70%. Bi-level positive airway pressure or adaptive servo-ventilation can be used for patients who are intolerant to continuous positive airway pressure. Other treatments include dental devices, surgery, and weight loss. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparison of manual versus automatic continuous positive airway pressure titration and the development of a predictive equation for therapeutic continuous positive airway pressure in Chinese patients with obstructive sleep apnoea.

PubMed

Luo, Jiaying; Xiao, Sichang; Qiu, Zhihui; Song, Ning; Luo, Yuanming

2013-04-01

Whether the therapeutic nasal continuous positive airway pressure (CPAP) derived from manual titration is the same as derived from automatic titration is controversial. The purpose of this study was to compare the therapeutic pressure derived from manual titration with automatic titration. Fifty-one patients with obstructive sleep apnoea (OSA) (mean apnoea/hypopnoea index (AHI) = 50.6 ± 18.6 events/h) who were newly diagnosed after an overnight full polysomnography and who were willing to accept CPAP as a long-term treatment were recruited for the study. Manual titration during full polysomnography monitoring and unattended automatic titration with an automatic CPAP device (REMstar Auto) were performed. A separate cohort study of one hundred patients with OSA (AHI = 54.3 ± 18.9 events/h) was also performed by observing the efficacy of CPAP derived from manual titration. The treatment pressure derived from automatic titration (9.8 ± 2.2 cmH(2)O) was significantly higher than that derived from manual titration (7.3 ± 1.5 cmH(2)O; P < 0.001) in 51 patients. The cohort study of 100 patients showed that AHI was satisfactorily decreased after CPAP treatment using a pressure derived from manual titration (54.3 ± 18.9 events/h before treatment and 3.3 ± 1.7 events/h after treatment; P < 0.001). The results suggest that automatic titration pressure derived from REMstar Auto is usually higher than the pressure derived from manual titration. © 2013 The Authors. Respirology © 2013 Asian Pacific Society of Respirology.

Effect of Sleep Apnea and Continuous Positive Airway Pressure on Cardiac Structure and Recurrence of Atrial Fibrillation

PubMed Central

Neilan, Tomas G.; Farhad, Hoshang; Dodson, John A.; Shah, Ravi V.; Abbasi, Siddique A.; Bakker, Jessie P.; Michaud, Gregory F.; van der Geest, Rob; Blankstein, Ron; Steigner, Michael; John, Roy M.; Jerosch‐Herold, Michael; Malhotra, Atul; Kwong, Raymond Y.

2013-01-01

Background Sleep apnea (SA) is associated with an increased risk of atrial fibrillation (AF). We sought to determine the effect of SA on cardiac structure in patients with AF, whether therapy for SA was associated with beneficial cardiac structural remodelling, and whether beneficial cardiac structural remodelling translated into a reduced risk of recurrence of AF after pulmonary venous isolation (PVI). Methods and Results A consecutive group of 720 patients underwent a cardiac magnetic resonance study before PVI. Patients with SA (n=142, 20%) were more likely to be male, diabetic, and hypertensive and have an increased pulmonary artery pressure, right ventricular volume, atrial dimensions, and left ventricular mass. Treated SA was defined as duration of continuous positive airway pressure therapy of >4 hours per night. Treated SA patients (n=71, 50%) were more likely to have paroxysmal AF, a lower blood pressure, lower ventricular mass, and smaller left atrium. During a follow‐up of 42 months, AF recurred in 245 patients. The cumulative incidence of AF recurrence was 51% in patients with SA, 30% in patients without SA, 68% in patients with untreated SA, and 35% in patients with treated SA. In a multivariable model, the presence of SA (hazard ratio 2.79, CI 1.97 to 3.94, P<0.0001) and untreated SA (hazard ratio 1.61, CI 1.35 to 1.92, P<0.0001) were highly associated with AF recurrence. Conclusions Patients with SA have an increased blood pressure, pulmonary artery pressure, right ventricular volume, left atrial size, and left ventricular mass. Therapy with continuous positive airway pressure is associated with lower blood pressure, atrial size, and ventricular mass, and a lower risk of AF recurrence after PVI. PMID:24275628

Bubble continuous positive airway pressure in a human immunodeficiency virus-infected infant

PubMed Central

McCollum, E. D.; Smith, A.; Golitko, C. L.

2014-01-01

SUMMARY World Health Organization-classified very severe pneumonia due to Pneumocystis jirovecii infection is recognized as a life-threatening condition in human immunodeficiency virus (HIV) infected infants. We recount the use of nasal bubble continuous positive airway pressure (BCPAP) in an HIV-infected African infant with very severe pneumonia and treatment failure due to suspected infection with P. jirovecii. We also examine the potential implications of BCPAP use in resource-poor settings with a high case index of acute respiratory failure due to HIV-related pneumonia, but limited access to mechanical ventilation. PMID:21396221

Influence of the Mode of Ventilation on Ketamine/Xylazine Requirements in Rabbits

DTIC Science & Technology

2007-01-01

latory continuous positive airway pressure ( CPAP ) of 7–10 cmH2O, and demand CPAP of 8– 10 cmH2O. (4) A fourth group, spontaneously ventilating (SV, n...minute)1) superimposed on 40 minute)1 low-frequency respiratory cycles, I:E ratio ¼ 1:1, oscillatory continuous positive airway pressure ( CPAP ) of 7–10...cmH2O and demand CPAP of 8–10 cmH2O, FiO2 ¼ 0.5. Rabbits from group 4 (SV; n ¼ 17) were anesthetized, the trachea intu- bated, and breathed air

Pressure-Relief Features of Fixed and Autotitrating Continuous Positive Airway Pressure May Impair Their Efficacy: Evaluation with a Respiratory Bench Model

PubMed Central

Zhu, Kaixian; Aouf, Sami; Roisman, Gabriel; Escourrou, Pierre

2016-01-01

Study Objectives: Pressure-relief features are aimed at improving the patient's comfort during continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea. The objective of this study was to determine the effect of these therapy features on fixed CPAP and autotitrating CPAP (APAP) treatment efficacy. Methods: Seven pressure-relief features applied by three CPAP devices were included in our study (Remstar Auto: C-Flex 3, C-Flex+ 3, A-Flex 3, P-Flex; AirSense 10: EPR 3; Prisma 20A: SoftPAP 2 and 3). In fixed CPAP, the devices were subjected to a 10-min bench-simulated obstructive apnea sequence (initial apnea-hypopnea index, AHI = 60/h) with and without pressure-relief features. In APAP, the sequence was lengthened to 4.2 h (initial AHI = 58.6/h). The residual AHI and mean/median pressure were compared with and without pressure-relief features. Results: Compared to conventional CPAP, where pressure was adjusted to be just sufficient to control the simulated obstructive events, C-Flex+ 3, P-Flex, and EPR 3 failed to normalize the breathing flow and did not reduce the AHI. The mean pressures with the three features, respectively, were 1.8, 2.6, and 2.6 cmH2O lower than the conventional CPAP. Compared to conventional APAP, similar levels of control were observed with pressure-relief features, apart from P-Flex where the delivered mean pressure was lower and residual AHI greater. The device-reported mean/median pressures in APAP with A-Flex 3, P-Flex, EPR 3, and SoftPAP 3 were higher than that measured on the bench. Conclusions: Pressure-relief features may attenuate CPAP efficacy if not adjusted for at the time of their introduction. In clinical practice, efficacy can be ensured by increasing the therapeutic pressure delivered by fixed CPAP or by enabling the pressure-relief features prior to initial pressure titration. Device-reported pressures in APAP devices with pressure relief activated may overstate delivered pressures. Citation: Zhu K, Aouf S, Roisman G, Escourrou P. Pressure-relief features of fixed and autotitrating continuous positive airway pressure may impair their efficacy: evaluation with a respiratory bench model. J Clin Sleep Med 2016;12(3):385–392. PMID:26564383

Case of postural complex sleep apnea: Effect of gravitational forces

PubMed Central

Pawar, Kamender Singh; Goyal, Abhishek; Khurana, Alkesh; Kumar, Senthil; Sen, Amit Kumar

2017-01-01

We report a case of an elderly male with predominant obstructive sleep apnea and who developed or complex sleep apnea (CxSA) at the start of continuous positive airway pressure (CPAP) titration. This CxSA was more prominent in supine position, and he was not settling with either CPAP/bilevel positive airway pressure (PAP) in supine position. He finally settled with CPAP along with position therapy. This case highlights the importance of treating CxSA with basic PAP modes like CPAP along with positional therapy before switching to costlier therapies such as adaptive servo-ventilation. PMID:28671174

[The numerical simulation of the internal flow field inside the pressure generator of a continuous positive airway pressure ventilator].

PubMed

Cheng, Yunzhang; Zhu, Lihua; Zhang, Weiguo; Wu, Wenquan

2011-12-01

The problem of noise in ventilator has always been an important topic to study in the development of the ventilator. A great number of data are showing that there are still large gaps of research and application levels in noise control of the ventilator between China and some more advanced foreign countries. In this study, with cooperation of the Shanghai Medical Equipment Limited Liability Company, we used the computational fluid dynamics (CFD), software FLUENT, adopted the standard k-epsilon turbulence model and the SIMPLE algorithm to simulate the inner flow field of the continuous positive airway pressure (CPAP) ventilator's pressure generator. After a detailed analysis, we figured out that there are several deficiencies in this ventilator, like local reflow in volute, uneven velocity distribution and local negative pressure in inlet of the impeller, which easily lead to noise and affect the ventilator's performances. So, it needs to be improved to a certain extent.

The nursing care of the infant receiving bubble CPAP therapy.

PubMed

Bonner, Krista M; Mainous, Rosalie O

2008-04-01

There are increasing numbers of low birth-weight and premature infants surviving with conditions such as chronic lung disease or bronchopulmonary dysplasia due to complications of assisted mechanical ventilation and other factors. Continuous positive airway pressure (CPAP) has been used as an alternative respiratory treatment to prevent and manage lung disease in preterm infants since the 1970s. Evidence has demonstrated the usefulness of CPAP in the delivery room, as a rescue therapy, as an extubation tool, and a method for managing apnea of prematurity. Bubble CPAP is a unique, simple, inexpensive way of providing continuous positive pressure to infants. Some background and training in the setup, care, and evaluation of the infant on bubble CPAP is essential for positive outcomes.

A Randomized Crossover Trial Comparing Autotitrating and Continuous Positive Airway Pressure in Subjects With Symptoms of Aerophagia: Effects on Compliance and Subjective Symptoms

PubMed Central

Shirlaw, Teresa; Hanssen, Kevin; Duce, Brett; Hukins, Craig

2017-01-01

Study Objectives: To assess the benefit and tolerance of autotitrating positive airway pressure (APAP) versus continuous positive airway pressure (CPAP) in subjects who experience aerophagia. Methods: This is the report of a prospective, two-week, double-blinded, randomized crossover trial set in an Australian clinical sleep laboratory in a tertiary hospital. Fifty-six subjects who reported symptoms of aerophagia that they attributed to CPAP were recruited. Full face masks were used by 39 of the 56 subjects recruited. Subjects were randomly and blindly allocated to either CPAP at their treatment recommended pressure or APAP 6–20 cm H2O, in random order. Subjects spent two weeks on each therapy mode. Therapy usage hours, 95th centile pressure, maximum pressure, 95th centile leak, and residual apnea-hypopnea index (AHI) were reported at the end of each two-week treatment period. Functional Outcome of Sleepiness Questionnaire, Epworth Sleepiness Scale, and visual analog scale to measure symptoms of aerophagia were also completed at the end of each 2-week treatment arm. Results: The median pressure (P < .001) and 95th centile pressure (P < .001) were reduced with APAP but no differences in compliance (P = .120) and residual AHI were observed. APAP reduced the symptoms of bloating (P = .011), worst episode of bloating (P = .040), flatulence (P = .010), and belching (P = .001) compared to CPAP. There were no differences in Epworth Sleepiness Scale or Functional Outcome of Sleepiness Questionnaire outcomes between CPAP and APAP. Conclusions: APAP therapy reduces the symptoms of aerophagia while not affecting compliance when compared with CPAP therapy. Clinical Trial Registration: Australian and New Zealand Clinical Trials Registry at https://www.anzctr.org.au, trial number ACTRN12611001250921. Commentary: A commentary on this article appears in this issue on page 859. Citation: Shirlaw T, Hanssen K, Duce B, Hukins C. A randomized crossover trial comparing autotitrating and continuous positive airway pressure in subjects with symptoms of aerophagia: effects on compliance and subjective symptoms. J Clin Sleep Med. 2017;13(7):881–888. PMID:28558864

40 CFR 60.4880 - How do I develop a site-specific monitoring plan for my continuous monitoring, bag leak detection...

Code of Federal Regulations, 2011 CFR

2011-07-01

... this section. (1) Install the flow sensor and other necessary equipment in a position that provides a representative flow. (2) Use a flow sensor with a measurement sensitivity of no greater than 2 percent of the...) Install the pressure sensor(s) in a position that provides a representative measurement of the pressure (e...

Oral continuous positive airway pressure (CPAP) following nasal injury in a preterm infant.

PubMed

Carlisle, H R; Kamlin, C O F; Owen, L S; Davis, P G; Morley, C J

2010-03-01

Non-invasive respiratory support is increasingly popular but is associated with complications including nasal trauma. The present report describes a novel method of oral continuous positive airway pressure (CPAP) delivery in an extremely premature infant with severe nasal septum erosion. The distal end of a cut down endotracheal tube was passed through a small hole made in the teat of a dummy (infant pacifier) and sutured in place. The dummy was secured in the infant's mouth and CPAP was delivered to the pharynx. The device was well tolerated and the infant was successfully managed using this technique for 48 days, avoiding endotracheal intubation and ventilation.

Bilateral parotitis in a patient under continuous positive airway pressure treatment.

PubMed

Abdullayev, Ruslan; Saral, Filiz Cosku; Kucukebe, Omer Burak; Sayiner, Hakan Sezgin; Bayraktar, Cem; Akgun, Sadik

Many conditions such as bacterial and viral infectious diseases, mechanical obstruction due to air and calculi and drugs can cause parotitis. We present a case of unusual bilateral parotitis in a patient under non-invasive continuous positive airway pressure (CPAP) therapy for chronic obstructive pulmonary disease exacerbation in intensive care unit. A 36-year-old patient was admitted to intensive care unit with the diagnosis of chronic obstructive pulmonary disease exacerbation. Antibiotherapy, bronchodilator therapy and non-invasive positive pressure ventilation were applied as treatment regimen. Painless swellings developed on the 3rd day of admission on the right and a day after this on the left parotid glands. Amylase levels were increased and ultrasonographic evaluation revealed bilateral parotitis. No intervention was made and the therapy was continued. The patient was discharged on the 6th day with clinical improvement and regression of parotid swellings without any complications. Parotitis may have occurred after retrograde air flow in the Stensen duct during CPAP application. After the exclusion of possible viral and bacteriological etiologies and possible drug reactions we can focus on this diagnosis. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

Continuous positive airway pressure improves sleep and daytime sleepiness in patients with Parkinson disease and sleep apnea.

PubMed

Neikrug, Ariel B; Liu, Lianqi; Avanzino, Julie A; Maglione, Jeanne E; Natarajan, Loki; Bradley, Lenette; Maugeri, Alex; Corey-Bloom, Jody; Palmer, Barton W; Loredo, Jose S; Ancoli-Israel, Sonia

2014-01-01

Obstructive sleep apnea (OSA), common in Parkinson disease (PD), contributes to sleep disturbances and daytime sleepiness. We assessed the effect of continuous positive airway pressure (CPAP) on OSA, sleep, and daytime sleepiness in patients with PD. This was a randomized placebo-controlled, crossover design. Patients with PD and OSA were randomized into 6 w of therapeutic treatment or 3 w of placebo followed by 3 w of therapeutic treatment. Patients were evaluated by polysomnography (PSG) and multiple sleep latency test (MSLT) pretreatment (baseline), after 3 w, and after 6 w of CPAP treatment. Analyses included mixed models, paired analysis, and within-group analyses comparing 3 w to 6 w of treatment. Sleep laboratory. Thirty-eight patients with PD (mean age = 67.2 ± 9.2 y; 12 females). Continuous positive airway pressure. PSG OUTCOME MEASURES: sleep efficiency, %sleep stages (N1, N2, N3, R), arousal index, apnea-hypopnea index (AHI), and % time oxygen saturation < 90% (%time SaO2 < 90%). MSLT outcome measures: mean sleep-onset latency (MSL). There were significant group-by-time interactions for AHI (P < 0.001), % time SaO2 < 90% (P = 0.02), %N2 (P = 0.015) and %N3 (P = 0.014). Subjects receiving therapeutic CPAP showed significant decrease in AHI, %time SaO2 < 90%, %N2, and significant increase in %N3 indicating effectiveness of CPAP in the treatment of OSA, improvement in nighttime oxygenation, and in deepening sleep. The paired sample analyses revealed that 3 w of therapeutic treatment resulted in significant decreases in arousal index (t = 3.4, P = 0.002). All improvements after 3 w were maintained at 6 w. Finally, 3 w of therapeutic CPAP also resulted in overall decreases in daytime sleepiness (P = 0.011). Therapeutic continuous positive airway pressure versus placebo was effective in reducing apnea events, improving oxygen saturation, and deepening sleep in patients with Parkinson disease and obstructive sleep apnea. Additionally, arousal index was reduced and effects were maintained at 6 weeks. Finally, 3 weeks of continuous positive airway pressure treatment resulted in reduced daytime sleepiness measured by multiple sleep latency test. These results emphasize the importance of identifying and treating obstructive sleep apnea in patients with Parkinson disease.

Bi-level positive airway pressure ventilation for treating heart failure with central sleep apnea that is unresponsive to continuous positive airway pressure.

PubMed

Dohi, Tomotaka; Kasai, Takatoshi; Narui, Koji; Ishiwata, Sugao; Ohno, Minoru; Yamaguchi, Tetsu; Momomura, Shin-Ichi

2008-07-01

Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) is associated with a poor prognosis in patients with heart failure (HF). However, some patients do not respond to continuous positive airway pressure (CPAP), so other therapeutic modalities should be considered, such as bi-level positive airway pressure (PAP), which also assists respiration and might be effective for such patients. The 20 patients with HF because of left ventricular systolic dysfunction were assessed: 8 had ischemic etiology, and all had severe CSA according to the apnea - hypopnea index (AHI) determined by polysomnography. All diagnosed patients underwent repeat polysomnography using CPAP. The AHI improved significantly in 11 (AHI <15), but only slightly in 9, in whom the AHI remained high (>or=15). Bi-level PAP titration significantly improved the AHI in the latter group. Those who were unresponsive to CPAP had significantly lower PaCO(2), higher plasma brain natriuretic peptide (BNP), longer mean duration of CSR and fewer obstructive episodes than CPAP responders. After 6 months of positive airway support with either CPAP (n=9) or bi-level PAP (n=7), BNP levels significantly decreased and left ventricular ejection fraction significantly increased. Bi-level PAP could be an effective alternative for patients with HF and pure CSR-CSA who are unresponsive to CPAP.

49 CFR 193.2513 - Transfer procedures.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY LIQUEFIED NATURAL GAS FACILITIES... transfer position; and (7) Verify that transfers into a pipeline system will not exceed the pressure or...

Impact of continuous positive airway pressure (CPAP) on the respiratory capacity of chronic kidney disease patients under hemodialysis treatment.

PubMed

Xavier, Vivian Bertoni; Roxo, Renata Spósito; Miorin, Luiz Antônio; Dos Santos Alves, Vera Lúcia; Dos Santos Sens, Yvoty Alves

2015-06-01

Chronic kidney disease (CKD) patients on long-term dialysis present changes in pulmonary function and respiratory muscle strength, negatively influencing physical capacity. To analyze the impact of a continuous positive airway pressure (CPAP) protocol on the respiratory capacity of CKD patients under hemodialysis. A randomized clinical trial was conducted involving 40 CKD patients 19-83 years old divided into two groups: control (n = 20) and CPAP (n = 20). Subjects were assessed on the respiratory muscle function test, maximal respiratory pressures, peak flow and 6-min walk test, at baseline and again at the 2-month follow-up. CPAP group patients were submitted to CPAP protocol (PEEP: 5 cm H2O, flow: 15 L/min, FiO2: 33 %) three times per week during hemodialysis sessions. The CPAP group showed higher forced vital capacity, forced expiratory volume in one second, peak expiratory flow, maximal inspiratory pressure, peak flow, as well as lower systolic blood pressure, heart rate, respiratory rate and Borg scale, in addition to a longer distance travelled on the 6-min walk test, compared with the control group. The introduction of a CPAP protocol during hemodialysis sessions had a positive impact on pulmonary function and physical capacity in CKD patients.

Servo Controlled Variable Pressure Modification to Space Shuttle Hydraulic Pump

NASA Technical Reports Server (NTRS)

Kouns, H. H.

1983-01-01

Engineering drawings show modifications made to the constant pressure control of the model AP27V-7 hydraulic pump to an electrically controlled variable pressure setting compensator. A hanger position indicator was included for continuously monitoring hanger angle. A simplex servo driver was furnished for controlling the pressure setting servovalve. Calibration of the rotary variable displacement transducer is described as well as pump performance and response characteristics.

Nasal bi-level positive airway pressure (BiPAP) versus nasal continuous positive airway pressure (CPAP) in preterm infants ≤32 weeks: A retrospective cohort study.

PubMed

Rong, Zhi-Hui; Li, Wen-Bin; Liu, Wei; Cai, Bao-Huan; Wang, Jing; Yang, Min; Li, Wei; Chang, Li-Wen

2016-05-01

To investigate whether Bi-level positive airway pressure (BiPAP), compared with nasal continuous positive airway pressure (CPAP), is a more effective therapeutic strategy in preterm infants ≤32 weeks. All inborn infants between 26(+1) and 32(+6) weeks' gestation, admitted to the neonatal intensive care unit (NICU ) of Tongji Medical Hospital between 1 January, 2010 and 31 December, 2011 (the 2010-2011 cohort or CPAP cohort) and between 1 January, 2012 and 31 December, 2013 (the 2012-2013 cohort or BiPAP cohort), were retrospectively identified. The primary outcome was intubation in infants < 72 h of age; secondary outcomes were mortality and the incidence of bronchopulmonary dysplasia (BPD). There were 213 in the 2010-2011 cohort and 243 infants in the 2012-2013 cohort. There were fewer infants intubated within the first 72 h of age in the 2012-2013 cohort than in the 2010-2011 cohort (15% vs. 23%, P < 0.05). Of the infants who received some form of positive airway pressure, 12/94 (13%) of infants on BiPAP versus 23/74 (31%) on CPAP were subsequently intubated (P < 0.01). There was no difference in the incidence of moderate and severe BPD between the two groups (7% vs. 8%, P=0.52). In this retrospective cohort study, we found BiPAP, compared with CPAP, reduced the need for intubation within the first 72 h of age. © 2016 Paediatrics and Child Health Division (The Royal Australasian College of Physicians).

The estimated sensitivity and specificity of compartment pressure monitoring for acute compartment syndrome.

PubMed

McQueen, Margaret M; Duckworth, Andrew D; Aitken, Stuart A; Court-Brown, Charles M

2013-04-17

The aim of our study was to document the estimated sensitivity and specificity of continuous intracompartmental pressure monitoring for the diagnosis of acute compartment syndrome. From our prospective trauma database, we identified all patients who had sustained a tibial diaphyseal fracture over a ten-year period. A retrospective analysis of 1184 patients was performed to record and analyze the documented use of continuous intracompartmental pressure monitoring and the use of fasciotomy. A diagnosis of acute compartment syndrome was made if there was escape of muscles at fasciotomy and/or color change in the muscles or muscle necrosis intraoperatively. A diagnosis of acute compartment syndrome was considered incorrect if it was possible to close the fasciotomy wounds primarily at forty-eight hours. The absence of acute compartment syndrome was confirmed by the absence of neurological abnormality or contracture at the time of the latest follow-up. Of 979 monitored patients identified, 850 fit the inclusion criteria with a mean age of thirty-eight years (range, twelve to ninety-four years), and 598 (70.4%) were male (p < 0.001). A total of 152 patients (17.9%) underwent fasciotomy for the treatment of acute compartment syndrome: 141 had acute compartment syndrome (true positives), six did not have it (false positives), and five underwent fasciotomy despite having a normal differential pressure reading, with subsequent operative findings consistent with acute compartment syndrome (false negatives). Of the 698 patients (82.1%) who did not undergo fasciotomy, 689 had no evidence of any late sequelae of acute compartment syndrome (true negatives) at a mean follow-up time of fifty-nine weeks. The estimated sensitivity of intracompartmental pressure monitoring for suspected acute compartment syndrome was 94%, with an estimated specificity of 98%, an estimated positive predictive value of 93%, and an estimated negative predictive value of 99%. The estimated sensitivity and specificity of continuous intracompartmental pressure monitoring for the diagnosis of acute compartment syndrome following tibial diaphyseal fracture are high; continuous intracompartmental pressure monitoring should be considered for patients at risk for acute compartment syndrome.

Continuous Positive Airway Pressure Prevents Hypoxia in Dental Patient with Obstructive Sleep Apnea Syndrome under Intravenous Sedation.

PubMed

Kasatkin, Anton A; Reshetnikov, Aleksei P; Urakov, Aleksandr L; Baimurzin, Dmitrii Y

2017-01-01

Use of sedation in patients with obstructive sleep apnea (OSA) in dentistry is limited. Hypoxia may develop during medication sleep in dental patients with OSA because of repetitive partial or complete obstruction of the upper airway. In this regard, anesthesiologists prefer not to give any sedative to surgical patients with OSA or support the use of general anesthesia due to good airway control. We report a case where we could successfully sedate a dental patient with OSA using intraoperative continuous positive airway pressure (CPAP) without hypoxia. Use of sedation and intraoperative CPAP in patients with OSA may be considered only if the effectiveness at home CPAP therapy is proven.

Effect of continuous positive airway pressure therapy on hypothalamic-pituitary-adrenal axis function and 24-h blood pressure profile in obese men with obstructive sleep apnea syndrome.

PubMed

Carneiro, Gláucia; Togeiro, Sônia Maria; Hayashi, Lílian F; Ribeiro-Filho, Fernando Flexa; Ribeiro, Artur Beltrame; Tufik, Sérgio; Zanella, Maria Teresa

2008-08-01

Obstructive sleep apnea syndrome (OSAS) increases the risk of cardiovascular events. Sympathetic nervous system and hypothalamic-pituitary-adrenal (HPA) axis activation may be the mechanism of this relationship. The aim of this study was to evaluate HPA axis and ambulatory blood pressure monitoring in obese men with and without OSAS and to determine whether nasal continuous positive airway pressure therapy (nCPAP) influenced responses. Twenty-four-hour ambulatory blood pressure monitoring and overnight cortisol suppression test with 0.25 mg of dexamethasone were performed in 16 obese men with OSAS and 13 obese men controls. Nine men with severe apnea were reevaluated 3 mo after nCPAP therapy. Body mass index and blood pressure of OSAS patients and obese controls were similar. In OSAS patients, the percentage of fall in systolic blood pressure at night (P = 0.027) and salivary cortisol suppression postdexamethasone (P = 0.038) were lower, whereas heart rate (P = 0.022) was higher compared with obese controls. After nCPAP therapy, patients showed a reduction in heart rate (P = 0.036) and a greater cortisol suppression after dexamethasone (P = 0.001). No difference in arterial blood pressure (P = 0.183) was observed after 3 mo of nCPAP therapy. Improvement in cortisol suppression was positively correlated with an improvement in apnea-hypopnea index during nCPAP therapy (r = 0.799, P = 0.010). In conclusion, men with OSAS present increased postdexamethasone cortisol levels and heart rate, which were recovered by nCPAP.

Clinical predictors of effective continuous positive airway pressure in patients with obstructive sleep apnea/hypopnea syndrome.

PubMed

Lai, Chi-Chih; Friedman, Michael; Lin, Hsin-Ching; Wang, Pa-Chun; Hwang, Michelle S; Hsu, Cheng-Ming; Lin, Meng-Chih; Chin, Chien-Hung

2015-08-01

To identify standard clinical parameters that may predict the optimal level of continuous positive airway pressure (CPAP) in adult patients with obstructive sleep apnea/hypopnea syndrome (OSAHS). This is a retrospective study in a tertiary academic medical center that included 129 adult patients (117 males and 12 females) with OSAHS confirmed by diagnostic polysomnography (PSG). All OSAHS patients underwent successful full-night manual titration to determine the optimal CPAP pressure level for OSAHS treatment. The PSG parameters and completed physical examination, including body mass index, tonsil size grading, modified Mallampati grade (also known as updated Friedman's tongue position [uFTP]), uvular length, neck circumference, waist circumference, hip circumference, thyroid-mental distance, and hyoid-mental distance (HMD) were recorded. When the physical examination variables and OSAHS disease were correlated singly with the optimal CPAP pressure, we found that uFTP, HMD, and apnea/hypopnea index (AHI) were reliable predictors of CPAP pressures (P = .013, P = .002, and P < .001, respectively, by multiple regression). When all important factors were considered in a stepwise multiple linear regression analysis, a significant correlation with optimal CPAP pressure was formulated by factoring the uFTP, HMD, and AHI (optimal CPAP pressure = 1.01 uFTP + 0.74 HMD + 0.059 AHI - 1.603). This study distinguished the correlation between uFTP, HMD, and AHI with the optimal CPAP pressure. The structure of the upper airway (especially tongue base obstruction) and disease severity may predict the effective level of CPAP pressure. 4. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

[Effect of nasal CPAP on human diaphragm position and lung volume].

PubMed

Yoshimura, N; Abe, T; Kusuhara, N; Tomita, T

1994-11-01

The cephalic margin of the zone of apposition (ZOA) was observed with ultrasonography at ambient pressure and during nasal continuous positive airway pressure (nasal CPAP) in nine awake healthy males in a supine position. In a relaxed state at ambient pressure, there was a significant (p < 0.001) linear relationship between lung volume and the movement of the cephalic margin of the ZOA over the range from maximum expiratory position (MEP) to maximum inspiratory position (MIP). With nasal CPAP, functional residual capacity increased significantly (p < 0.01) in proportion to the increase in CPAP. At 20 cmH2O CPAP, the mean increase in volume at end expiration was 36% of the vital capacity measured at ambient pressure. The cephalic margin of the ZOA moved significantly (p < 0.01) in a caudal direction as CPAP was increased. At 20 cmH2O CPAP, the cephalic margin of the ZOA at end expiratory position (EEP) had moved 55% of the difference from MIP to MEP measured at ambient pressure. The end expiratory diaphragm position during nasal CPAP was lower than the diaphragm position at ambient pressure when lung volumes were equal. These results suggest that during nasal CPAP the chest wall is distorted from its relaxed configuration, with a decrease in rib cage expansion and an increase in outward displacement of the abdominal wall.

Continuous Positive Airway Pressure (CPAP)

MedlinePlus

... Programs Professional Development Home AcademyU Home Study Course Maintenance of Certification Conferences & Events Practice Management Home Resources Quality Clinical Data Registry Research Reimbursement ...

Tracheobronchomegaly associated tracheomalacia: analysis by sleep study.

PubMed

Sundaram, P; Joshi, J M

2004-01-01

Tracheobronchomegaly (TBM) occasionally may progress to extensive tracheomalacia which leads to respiratory failure. Spirometry, dynamic expiratory multidetector computed tomography (CT), bronchoscopy are used to diagnose patients of suspected tracheobronchomalacia. We used the technique of night-time monitoring of respiratory variables to show the presence of respiratory abnormalities during sleep and which was corrected by applying nasal continuous positive airway pressure (CPAP). The study showed the presence of both apnoea and hypopnoeas, which were obstructive in nature with an apnoea-hypopnoea index (AHI) of 11, no snoring and associated oxygen desaturation of 75 per cent. A second overnight study with nasal continuous positive airway pressure at a critical pressure of 8 cm, the AHI decreased to 3 along with no drop in oxygen saturation. This non-invasive technique should be considered as a diagnostic tool in tracheobronchomalacia and to know the outcome of CPAP, surgical or stent therapy in this condition.

Monitoring of intracranial compliance: correction for a change in body position.

PubMed

Raabe, A; Czosnyka, M; Piper, I; Seifert, V

1999-01-01

The objectives of our study were 1. to investigate whether the intracranial compliance changes with body position; 2. to test if the pressure-volume index (PVI) calculation is affected by different body positions; 3. to define the optimal parameter to correct PVI for changes in body position and 4. to investigate the physiological meaning of the constant term (P0) in the model of the intracranial volume-pressure relationship. Thirteen patients were included in this study. All patients were subjected to 2 to 3 different body positions. In each position, either classic bolus injection was performed for measurement of intracranial compliance and calculation of PVI or the new Spiegelberg compliance monitor was used to calculate PVI continuously. Four different models were used for calculating the constant pressure term P0 and the P0 corrected PVI values. Pressure volume index not corrected for the constant term P0 significantly decreased with elevating the patients head (r = 0.70, p < 0.0001). In contrast, volume-pressure response and ICP pulse amplitude did not change with position. Using the constant term P0 to correct the PVI we found no changes between the different body positions. Our results suggest that during the variation in body position there is no change in intracranial compliance but a change in hydrostatic offset pressure which causes a shifting of the volume-pressure curve along the pressure axis without its shape being affected. PVI measurements should either be performed only with the patient in the 0 degree recumbent position or that the PVI calculation should be corrected for the hydrostatic difference between the level of the ICP transducer and the hydrostatic indifference point of the craniospinal system close to the third thoracic vertebra.

Spontaneous Effort During Mechanical Ventilation: Maximal Injury With Less Positive End-Expiratory Pressure.

PubMed

Yoshida, Takeshi; Roldan, Rollin; Beraldo, Marcelo A; Torsani, Vinicius; Gomes, Susimeire; De Santis, Roberta R; Costa, Eduardo L V; Tucci, Mauro R; Lima, Raul G; Kavanagh, Brian P; Amato, Marcelo B P

2016-08-01

We recently described how spontaneous effort during mechanical ventilation can cause "pendelluft," that is, displacement of gas from nondependent (more recruited) lung to dependent (less recruited) lung during early inspiration. Such transfer depends on the coexistence of more recruited (source) liquid-like lung regions together with less recruited (target) solid-like lung regions. Pendelluft may improve gas exchange, but because of tidal recruitment, it may also contribute to injury. We hypothesize that higher positive end-expiratory pressure levels decrease the propensity to pendelluft and that with lower positive end-expiratory pressure levels, pendelluft is associated with improved gas exchange but increased tidal recruitment. Crossover design. University animal research laboratory. Anesthetized landrace pigs. Surfactant depletion was achieved by saline lavage in anesthetized pigs, and ventilator-induced lung injury was produced by ventilation with high tidal volume and low positive end-expiratory pressure. Ventilation was continued in each of four conditions: positive end-expiratory pressure (low or optimized positive end-expiratory pressure after recruitment) and spontaneous breathing (present or absent). Tidal recruitment was assessed using dynamic CT and regional ventilation/perfusion using electric impedance tomography. Esophageal pressure was measured using an esophageal balloon manometer. Among the four conditions, spontaneous breathing at low positive end-expiratory pressure not only caused the largest degree of pendelluft, which was associated with improved ventilation/perfusion matching and oxygenation, but also generated the greatest tidal recruitment. At low positive end-expiratory pressure, paralysis worsened oxygenation but reduced tidal recruitment. Optimized positive end-expiratory pressure decreased the magnitude of spontaneous efforts (measured by esophageal pressure) despite using less sedation, from -5.6 ± 1.3 to -2.0 ± 0.7 cm H2O, while concomitantly reducing pendelluft and tidal recruitment. No pendelluft was observed in the absence of spontaneous effort. Spontaneous effort at low positive end-expiratory pressure improved oxygenation but promoted tidal recruitment associated with pendelluft. Optimized positive end-expiratory pressure (set after lung recruitment) may reverse the harmful effects of spontaneous breathing by reducing inspiratory effort, pendelluft, and tidal recruitment.

Noninvasive ventilation.

PubMed

Rabatin, J T; Gay, P C

1999-08-01

Noninvasive ventilation refers to the delivery of assisted ventilatory support without the use of an endotracheal tube. Noninvasive positive pressure ventilation (NPPV) can be delivered by using a volume-controlled ventilator, a pressure-controlled ventilator, a bilevel positive airway pressure ventilator, or a continuous positive airway pressure device. During the past decade, there has been a resurgence in the use of noninvasive ventilation, fueled by advances in technology and clinical trials evaluating its use. Several manufacturers produce portable devices that are simple to operate. This review describes the equipment, techniques, and complications associated with NPPV and also the indications for both short-term and long-term applications. NPPV clearly represents an important addition to the techniques available to manage patients with respiratory failure. Future clinical trials evaluating its many clinical applications will help to define populations of patients most apt to benefit from this type of treatment.

Impact of continuous positive airway pressure on vascular endothelial growth factor in patients with obstructive sleep apnea: a meta-analysis.

PubMed

Qi, Jia-Chao; Zhang, LiangJi; Li, Hao; Zeng, Huixue; Ye, Yuming; Wang, Tiezhu; Wu, Qiyin; Chen, Lida; Xu, Qiaozhen; Zheng, Yifeng; Huang, Yaping; Lin, Li

2018-04-18

Cumulative evidence supports the clear relationship of obstructive sleep apnea (OSA) with cardiovascular disease (CVD). And, adherence to continuous positive airway pressure (CPAP) treatment alleviates the risk of CVD in subjects with OSA. Vascular endothelial growth factor (VEGF), a potent angiogenic cytokine regulated by hypoxia-inducible factor, stimulates the progression of CVD. Thus, whether treatment with CPAP can actually decrease VEGF in patients with OSA remains inconclusive. The purpose of the present study was to quantitatively evaluate the impact of CPAP therapy on VEGF levels in OSA patients. We systematically searched Web of Science, Cochrane Library, PubMed, and Embase databases that examined the impact of CPAP on VEGF levels in OSA patients prior to May 1, 2017. Related searching terms were "sleep apnea, obstructive," "sleep disordered breathing," "continuous positive airway pressure," "positive airway pressure," and "vascular endothelial growth factor." We used standardized mean difference (SMD) to analyze the summary estimates for CPAP therapy. Six studies involving 392 patients were eligible for the meta-analysis. Meta-analysis of the pooled effect showed that levels of VEGF were significantly decreased in patients with OSA before and after CPAP treatment (SMD = - 0.440, 95% confidence interval (CI) = - 0.684 to - 0.196, z = 3.53, p = 0.000). Further, results demonstrated that differences in age, body mass index, apnea-hypopnea index, CPAP therapy duration, sample size, and racial differences also affected CPAP efficacy. Improved endothelial function measured by VEGF may be associated with CPAP therapy in OSA patients. The use of VEGF levels may be clinically important in evaluating CVD for OSA patients. Further large-scale, well-designed long-term interventional investigations are needed to clarify this issue.

Effects of continuous positive airway pressure and isocapnic-hypoxia on cerebral autoregulation in patients with obstructive sleep apnoea.

PubMed

Waltz, Xavier; Beaudin, Andrew E; Hanly, Patrick J; Mitsis, Georgios D; Poulin, Marc J

2016-12-01

Altered cerebral autoregulation (CA) in obstructive sleep apnoea (OSA) patients may contribute to increased stroke risk in this population; the gold standard treatment for OSA is continuous positive airway pressure, which improves cerebrovascular regulation and may decrease the risk of stroke. Isocapnic-hypoxia impairs CA in healthy subjects, but it remains unknown in OSA whether impaired CA is further exacerbated by isocapnic-hypoxia and whether it is improved by treatment with continuous positive airway pressure. During normoxia, CA was altered in the more severe but not in the less severe OSA patients, while, in contrast, during isocapnic-hypoxia, CA was similar between groups and tended to improve in patients with more severe OSA compared to normoxia. From a clinical perspective, one month of continuous positive airway pressure treatment does not improve CA. From a physiological perspective, this study suggests that sympathetic overactivity may be responsible for altered CA in the more severe OSA patients. Cerebral autoregulation (CA) impairment may contribute to the increased risk of stroke associated with obstructive sleep apnoea (OSA). It is unknown if impaired CA is further exacerbated by isocapnic-hypoxia and whether it is improved by treatment of OSA with continuous positive airway pressure (CPAP). CA was assessed during wakefulness in 53 OSA patients (50.3 ± 9.3 years) and 21 controls (49.8 ± 8.6 years) at baseline and following a minimum of 1 month of effective CPAP therapy (OSA patients, n = 40). Control participants (n = 21) performed a follow-up visit to control for time effects within OSA patients between baseline and the post-CPAP visit. Beat-by-beat middle cerebral artery blood flow velocity and mean arterial blood pressure (MBP), and breath-by-breath end-tidal partial pressure of CO 2 (P ET ,CO2) were monitored. CA was determined during normoxia and isocapnic-hypoxia using transfer function (phase and gain) and coherence analysis (including multiple and partial coherence (using MBP and P ET ,CO2 as inputs)) in the very low frequency range (0.03-0.07 Hz). OSA patients were divided into two subgroups (less severe and more severe) based upon the median respiratory disturbance index (RDI). During normoxia, the more severe OSA patients (RDI 45.9 ± 10.3) exhibited altered CA compared to controls and the less severe OSA patients (RDI 24.5 ± 5.9). In contrast, during isocapnic-hypoxia, CA was similar between groups. CPAP had no effect on CA. In conclusion, CA is altered in the more severe OSA patients during normoxia but not during isocapnic-hypoxia and CPAP treatment does not impact CA. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Analysis of continuous GPS measurements from southern Victoria Land, Antarctica

USGS Publications Warehouse

Willis, Michael J.

2007-01-01

Several years of continuous data have been collected at remote bedrock Global Positioning System (GPS) sites in southern Victoria Land, Antarctica. Annual to sub-annual variations are observed in the position time-series. An atmospheric pressure loading (APL) effect is calculated from pressure field anomalies supplied by the European Centre for Medium-Range Weather Forecasts (ECMWF) model loading an elastic Earth model. The predicted APL signal has a moderate correlation with the vertical position time-series at McMurdo, Ross Island (International Global Navigation Satellite System Service (IGS) station MCM4), produced using a global solution. In contrast, a local solution in which MCM4 is the fiducial site generates a vertical time series for a remote site in Victoria Land (Cape Roberts, ROB4) which exhibits a low, inverse correlation with the predicted atmospheric pressure loading signal. If, in the future, known and well modeled geophysical loads can be separated from the time-series, then local hydrological loading, of interest for glaciological and climate applications, can potentially be extracted from the GPS time-series.

Aerophagia and Gastroesophageal Reflux Disease in Patients using Continuous Positive Airway Pressure: A Preliminary Observation

PubMed Central

Watson, Nathaniel F.; Mystkowski, Sue K.

2008-01-01

Study Objectives: Aerophagia is a complication of continuous positive airway pressure (CPAP) therapy for sleep disordered breathing (SDB), whereupon air is forced into the stomach and bowel. Associated discomfort can result in CPAP discontinuation. We hypothesize that aerophagia is associated with gastroesophageal reflux disease (GERD) via mechanisms involving GERD related lower esophageal sphincter (LES) compromise. Methods: Twenty-two subjects with aerophagia and 22 controls, matched for age, gender, and body mass index, who were being treated with CPAP for SDB were compared in regard to clinical aspects of GERD, GERD associated habits, SDB severity as measured by polysomnography, and mean CPAP pressure. Results: More subjects with aerophagia had symptoms of GERD (77.3% vs. 36.4%; p < 0.01) and were on GERD related medications (45.5% vs. 18.2%, p < 0.05) than controls. Regarding polysomnography, mean oxygen saturation percentages were lower in the aerophagia group than controls (95.0% vs. 96.5%, p < 0.05). No other differences were observed, including mean CPAP pressures. No one in the aerophagia group (vs. 27.3% of the control group) was a current tobacco user (p < 0.01). There was no difference in caffeine or alcohol use between the 2 groups. Conclusions: These results imply aerophagia is associated with GERD symptoms and GERD related medication use. This finding suggests a relationship between GERD related LES pathophysiology and the development of aerophagia in patients with SDB treated with CPAP. Citation: Watson NF; Mystkowski SK. Aerophagia and gastroesophageal reflux disease in patients using continuous positive airway pressure: a preliminary observation. J Clin Sleep Med 2008;4(5):434–438. PMID:18853700

Sibutramine versus continuous positive airway pressure in obese obstructive sleep apnoea patients.

PubMed

Ferland, A; Poirier, P; Sériès, F

2009-09-01

The aim of the present study was to compare the efficacy of 1 yr of sibutramine-induced weight loss versus continuous positive airway pressure (CPAP) treatment on sleep-disordered breathing, cardiac autonomic function and systemic blood pressure in obese patients with obstructive sleep apnoea. Subjects with a body mass index of > or =30 kg.m(-2) without previous treatment for obstructive sleep apnoea underwent either sibutramine (n = 22) or CPAP (n = 18) treatment for 1 yr. Sibutramine induced a 5.4+/-1.4 kg decrease in body weight compared to the CPAP group, in which no changes in anthropometric variables were observed. The CPAP treatment improved all sleep and respiratory variables, whereas sibutramine-induced weight loss improved only nocturnal arterial oxygen saturation profile. Only CPAP treatment improved night-time systolic and diastolic blood pressure and 24-h and daytime ambulatory diastolic blood pressure. Sibutramine-induced weight loss had no impact on indices of heart rate variability, whereas CPAP treatment increased daytime time domain indices. CPAP treatment for 1 yr had beneficial impacts on nocturnal breathing disturbances, and improved nocturnal oxygenation, night-time systolic and diastolic blood pressure, and daytime cardiac parasympathetic modulation. Sibutramine did not improve sleep-disordered breathing, systemic blood pressure or heart rate variability. There were no adverse effects, such as increment in blood pressure or arrhythmias, associated with this treatment regimen.

Symptoms of Aerophagia Are Common in Patients on Continuous Positive Airway Pressure Therapy and Are Related to the Presence of Nighttime Gastroesophageal Reflux

PubMed Central

Shepherd, Kelly; Hillman, David; Eastwood, Peter

2013-01-01

Study Objectives: Continuous positive airway pressure (CPAP), the mainstay treatment for obstructive sleep apnea (OSA), involves administration of air under pressure to the upper airway. A well-known but poorly understood side effect of positive airway pressure therapies is aerophagia, air entering the esophagus and stomach rather than the lungs. Gastric distension, a consequence of aerophagia, can increase gastroesophageal reflux (GER) by increasing transient lower esophageal sphincter relaxations, the most common cause of reflux. This study aimed to determine: (i) the prevalence of aerophagia symptoms in a group of OSA patients on CPAP therapy, and (ii) whether aerophagia symptoms are related to an increase in prevalence of GER symptoms. Methods: Consecutive OSA patients undergoing polysomnography for the purpose of optimizing their CPAP therapy completed a validated questionnaire regarding GER symptoms and aerophagia symptoms. Complete datasets were collected for 259 individuals (203 males). Results: The group with aerophagia symptoms (n = 130) had a greater prevalence of frequent (≥ once a week) GER symptoms (29% vs. 10%, p < 0.05) and nighttime GER symptoms (9 vs. 2%, p < 0.05) than those without aerophagia (n = 129). The group with nighttime GER symptoms (n = 27) had a greater prevalence of aerophagia symptoms (63% vs. 23%, p < 0.05) than those without nighttime GER symptoms (n = 232). Conclusions: In patients with OSA being treated with CPAP, the prevalence of GER and nighttime GER symptoms is greater in those with symptoms of aerophagia than those without. CPAP-induced aerophagia might precipitate GER, particularly nighttime GER, by exacerbating transient lower esophageal relaxations through gastric distension. Commentary: A commentary on this article appears in this issue on page 19. Citation: Shepherd K; Hillman D; Eastwood P. Symptoms of aerophagia are common in patients on continuous positive airway pressure therapy and are related to the presence of nighttime gastroesophageal reflux. J Clin Sleep Med 2013;9(1):13-17. PMID:23319899

Continuous Positive Airway Pressure (CPAP)

MedlinePlus

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The Age-Dependent Relationship between Blood Pressure and Cognitive Impairment: A Cross-Sectional Study in a Rural Area of Xi'an, China.

PubMed

Shang, Suhang; Li, Pei; Deng, Meiying; Jiang, Yu; Chen, Chen; Qu, Qiumin

2016-01-01

Hypertension is a modifiable risk factor for cognitive impairment, although the relationship between hypertension and cognitive impairment is not fully understood. The objective of this study was to investigate the effect of age on the relationship between blood pressure and cognitive impairment. Blood pressure and global cognitive function information was collected from 1799 participants (age 40-85) who lived in a village in the suburbs of Xi'an, China, during in-person interviews. Cognitive impairment was defined as a Mini-Mental State Examination (MMSE) score lower than the cutoff value. The effect of age on the relationship between blood pressure parameters [systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MABP), and high blood pressure (HBP, SBP≥140 mm Hg and/or DBP≥90 mm Hg)] and cognitive impairment was analyzed by logistic regression models using interaction and stratified analysis. Blood pressure and age were regarded as both continuous and categorical data. A total of 231 participants were diagnosed as having cognitive impairment based on our criteria. Interaction analysis for the total population showed that SBP (when regarded as continuous data) was positively correlated with cognitive impairment (OR = 1.130 [95% CI, 1.028-1.242] per 10mmHg, P = 0.011); however, the age by SBP interaction term was negatively correlated with cognitive impairment (OR = 0.989 [95% CI, 0.982-0.997] per 10mmHg×year, P = 0.006), indicating that the relationship between SBP and cognitive impairment was age-dependent (OR = 1.130×0.989(age-55.5) per 10mmHg,40 ≤age≤85). When the blood pressure and age were considered as binary data, the results were similar to those obtained when they were considered as continuous variables. Stratified multivariate analysis revealed that the relationship between SBP (when regarded as continuous data) and cognitive impairment was positive for patients aged 40-49 years (OR = 1.349 [95% CI: 1.039-1.753] per 10mmHg, P = 0.025) and 50-59 years (OR = 1.185 [95% CI: 1.028-1.366] per 10mmHg, P = 0.019), whereas it tended to be negative for patients aged 60-69 years (OR = 0.878 [95% CI: 0.729-1.058] per 10mmHg, P = 0.171) and ≥70 years (OR = 0.927 [95% CI: 0.772-1.113] per 10mmHg, P = 0.416). Results similar to those for SBP were obtained for DBP, MABP and HBP as well. Subsequently, SBP, DBP and MABP were transformed into categorical data (SBP<140mmHg, 140mmHg≤SBP<160mmHg, and SBP≥160mmHg; DBP<90mmHg, 90mmHg≤DBP<100mmHg, and DBP≥100mmHg; MABP<100mmHg, 100mmHg≤MABP<110mmHg, and MABP≥110mmHg), and the stratified multivariate analysis was repeated. This analysis showed that the age-dependent association continued to exist and was especially prominent in the SBP≥160 mmHg, DBP≥90 mmHg and MABP≥110 mmHg groups. Elevated blood pressure is positively correlated with cognitive impairment in the middle-aged, but this positive association declines with increasing age. These results indicated that specific blood pressure management strategies for various age groups may be crucial for maintaining cognitive vitality.

The Age-Dependent Relationship between Blood Pressure and Cognitive Impairment: A Cross-Sectional Study in a Rural Area of Xi'an, China

PubMed Central

Shang, Suhang; Li, Pei; Deng, Meiying; Jiang, Yu; Chen, Chen; Qu, Qiumin

2016-01-01

Background Hypertension is a modifiable risk factor for cognitive impairment, although the relationship between hypertension and cognitive impairment is not fully understood. The objective of this study was to investigate the effect of age on the relationship between blood pressure and cognitive impairment. Methods Blood pressure and global cognitive function information was collected from 1799 participants (age 40–85) who lived in a village in the suburbs of Xi'an, China, during in-person interviews. Cognitive impairment was defined as a Mini-Mental State Examination (MMSE) score lower than the cutoff value. The effect of age on the relationship between blood pressure parameters [systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MABP), and high blood pressure (HBP, SBP≥140 mm Hg and/or DBP≥90 mm Hg)] and cognitive impairment was analyzed by logistic regression models using interaction and stratified analysis. Blood pressure and age were regarded as both continuous and categorical data. Results A total of 231 participants were diagnosed as having cognitive impairment based on our criteria. Interaction analysis for the total population showed that SBP (when regarded as continuous data) was positively correlated with cognitive impairment (OR = 1.130 [95% CI, 1.028–1.242] per 10mmHg, P = 0.011); however, the age by SBP interaction term was negatively correlated with cognitive impairment (OR = 0.989 [95% CI, 0.982–0.997] per 10mmHg×year, P = 0.006), indicating that the relationship between SBP and cognitive impairment was age-dependent (OR = 1.130×0.989(age-55.5) per 10mmHg,40 ≤age≤85). When the blood pressure and age were considered as binary data, the results were similar to those obtained when they were considered as continuous variables. Stratified multivariate analysis revealed that the relationship between SBP (when regarded as continuous data) and cognitive impairment was positive for patients aged 40–49 years (OR = 1.349 [95% CI: 1.039–1.753] per 10mmHg, P = 0.025) and 50–59 years (OR = 1.185 [95% CI: 1.028–1.366] per 10mmHg, P = 0.019), whereas it tended to be negative for patients aged 60–69 years (OR = 0.878 [95% CI: 0.729–1.058] per 10mmHg, P = 0.171) and ≥70 years (OR = 0.927 [95% CI: 0.772–1.113] per 10mmHg, P = 0.416). Results similar to those for SBP were obtained for DBP, MABP and HBP as well. Subsequently, SBP, DBP and MABP were transformed into categorical data (SBP<140mmHg, 140mmHg≤SBP<160mmHg, and SBP≥160mmHg; DBP<90mmHg, 90mmHg≤DBP<100mmHg, and DBP≥100mmHg; MABP<100mmHg, 100mmHg≤MABP<110mmHg, and MABP≥110mmHg), and the stratified multivariate analysis was repeated. This analysis showed that the age-dependent association continued to exist and was especially prominent in the SBP≥160 mmHg, DBP≥90 mmHg and MABP≥110 mmHg groups. Conclusions Elevated blood pressure is positively correlated with cognitive impairment in the middle-aged, but this positive association declines with increasing age. These results indicated that specific blood pressure management strategies for various age groups may be crucial for maintaining cognitive vitality. PMID:27438476

Preventing Continuous Positive Airway Pressure Failure: Evidence-Based and Physiologically Sound Practices from Delivery Room to the Neonatal Intensive Care Unit.

PubMed

Wright, Clyde J; Sherlock, Laurie G; Sahni, Rakesh; Polin, Richard A

2018-06-01

Routine use of continuous positive airway pressure (CPAP) to support preterm infants with respiratory distress is an evidenced-based strategy to decrease incidence of bronchopulmonary dysplasia. However, rates of CPAP failure remain unacceptably high in very premature neonates, who are at high risk for developing bronchopulmonary dysplasia. Using the GRADE framework to assess the quality of available evidence, this article reviews strategies aimed at decreasing CPAP failure, starting with delivery room interventions and followed through to system-based efforts in the neonatal intensive care unit. Despite best efforts, some very premature neonates fail CPAP. Also reviewed are predictors of CPAP failure in this vulnerable population. Copyright © 2018 Elsevier Inc. All rights reserved.

Effect of continuous positive airway pressure on blood pressure and metabolic profile in women with sleep apnoea

PubMed Central

Gonzalez-Martinez, Monica; Sanchez-Armengol, Angeles; Jurado-Gamez, Bernabe; Cordero-Guevara, Jose; Reyes-Nuñez, Nuria; Troncoso, Maria F.; Abad-Fernandez, Araceli; Teran-Santos, Joaquin; Caballero-Rodriguez, Julian; Martin-Romero, Mercedes; Encabo-Motiño, Ana; Sacristan-Bou, Lirios; Navarro-Esteva, Javier; Somoza-Gonzalez, Maria; Masa, Juan F.; Sanchez-Quiroga, Maria A.; Jara-Chinarro, Beatriz; Orosa-Bertol, Belen; Martinez-Garcia, Miguel A.

2017-01-01

Continuous positive airway pressure (CPAP) reduces blood pressure levels in hypertensive patients with obstructive sleep apnoea (OSA). However, the role of CPAP in blood pressure and the metabolic profile in women has not yet been assessed. In this study we investigated the effect of CPAP on blood pressure levels and the glucose and lipid profile in women with moderate-to-severe OSA. A multicentre, open-label, randomised controlled trial was conducted in 307 women diagnosed with moderate-to-severe OSA (apnoea–hypopnoea index ≥15 events·h–1) in 19 Spanish Sleep Units. Women were randomised to CPAP (n=151) or conservative treatment (n=156) for 12 weeks. Changes in office blood pressure measures as well as in the glucose and lipid profile were assessed in both groups. Compared with the control group, the CPAP group achieved a significantly greater decrease in diastolic blood pressure (−2.04 mmHg, 95% CI −4.02– −0.05; p=0.045), and a nonsignificantly greater decrease in systolic blood pressure (−1.54 mmHg, 95% CI −4.58–1.51; p=0.32) and mean blood pressure (−1.90 mmHg, 95% CI −4.0–0.31; p=0.084). CPAP therapy did not change any of the metabolic variables assessed. In women with moderate-to-severe OSA, 12 weeks of CPAP therapy improved blood pressure, especially diastolic blood pressure, but did not change the metabolic profile, compared with conservative treatment. PMID:28798089

Effect of continuous positive airway pressure on blood pressure and metabolic profile in women with sleep apnoea.

PubMed

Campos-Rodriguez, Francisco; Gonzalez-Martinez, Monica; Sanchez-Armengol, Angeles; Jurado-Gamez, Bernabe; Cordero-Guevara, Jose; Reyes-Nuñez, Nuria; Troncoso, Maria F; Abad-Fernandez, Araceli; Teran-Santos, Joaquin; Caballero-Rodriguez, Julian; Martin-Romero, Mercedes; Encabo-Motiño, Ana; Sacristan-Bou, Lirios; Navarro-Esteva, Javier; Somoza-Gonzalez, Maria; Masa, Juan F; Sanchez-Quiroga, Maria A; Jara-Chinarro, Beatriz; Orosa-Bertol, Belen; Martinez-Garcia, Miguel A

2017-08-01

Continuous positive airway pressure (CPAP) reduces blood pressure levels in hypertensive patients with obstructive sleep apnoea (OSA). However, the role of CPAP in blood pressure and the metabolic profile in women has not yet been assessed. In this study we investigated the effect of CPAP on blood pressure levels and the glucose and lipid profile in women with moderate-to-severe OSA.A multicentre, open-label, randomised controlled trial was conducted in 307 women diagnosed with moderate-to-severe OSA (apnoea-hypopnoea index ≥15 events·h -1 ) in 19 Spanish Sleep Units. Women were randomised to CPAP (n=151) or conservative treatment (n=156) for 12 weeks. Changes in office blood pressure measures as well as in the glucose and lipid profile were assessed in both groups.Compared with the control group, the CPAP group achieved a significantly greater decrease in diastolic blood pressure (-2.04 mmHg, 95% CI -4.02- -0.05; p=0.045), and a nonsignificantly greater decrease in systolic blood pressure (-1.54 mmHg, 95% CI -4.58-1.51; p=0.32) and mean blood pressure (-1.90 mmHg, 95% CI -4.0-0.31; p=0.084). CPAP therapy did not change any of the metabolic variables assessed.In women with moderate-to-severe OSA, 12 weeks of CPAP therapy improved blood pressure, especially diastolic blood pressure, but did not change the metabolic profile, compared with conservative treatment. Copyright ©ERS 2017.

Measurements of emission-propagation phenomena in low-energy atmospheric-pressure helium plasma

NASA Astrophysics Data System (ADS)

Yamada, Hiromasa; Shimizu, Tetsuji; Fujiwara, Masanori; Kato, Susumu; Fujiwara, Yutaka; Itagaki, Hirotomo; Kiyama, Satoru; Kim, Jaeho; Ikehara, Sanae; Shimizu, Nobuyuki; Nakanishi, Hayao; Ikehara, Yuzuru; Sakakita, Hajime

2018-05-01

In a low-temperature atmospheric pressure plasma jet using helium gas, emission-propagation phenomena, such as streamers and striations were measured using a high-speed intensified charge-coupled device camera. A particular focus was placed on the study of the dependence of the phenomena on the distance between the nozzle of the plasma device and a target plate. When the distance decreased, a transition from the positive streamer to a spatially continuous emission resulted. A further distance reduction resulted in a new propagation mode in which the positive and negative streamers appeared alternately with different current waveforms over two cycles of applied voltage. This phenomenon may be related to residual charges of the preceding cycle when streamer propagation begins. Striation structures were observed in the tail of the positive streamer head and in the successive spatially continuous-emission region. These structures can be measured only within a shorter period than one voltage cycle.

In vitro biomechanical comparison of three different types of single- and double-row arthroscopic rotator cuff repairs: analysis of continuous bone-tendon contact pressure and surface during different simulated joint positions.

PubMed

Grimberg, Jean; Diop, Amadou; Kalra, Kunal; Charousset, Christophe; Duranthon, Louis-Denis; Maurel, Nathalie

2010-03-01

We assessed bone-tendon contact surface and pressure with a continuous and reversible measurement system comparing 3 different double- and single-row techniques of cuff repair with simulation of different joint positions. We reproduced a medium supraspinatus tear in 24 human cadaveric shoulders. For the 12 right shoulders, single-row suture (SRS) and then double-row bridge suture (DRBS) were used. For the 12 left shoulders, DRBS and then double-row cross suture (DRCS) were used. Measurements were performed before, during, and after knot tying and then with different joint positions. There was a significant increase in contact surface with the DRBS technique compared with the SRS technique and with the DRCS technique compared with the SRS or DRBS technique. There was a significant increase in contact pressure with the DRBS technique and DRCS technique compared with the SRS technique but no difference between the DRBS technique and DRCS technique. The DRCS technique seems to be superior to the DRBS and SRS techniques in terms of bone-tendon contact surface and pressure. Copyright 2010 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Noninvasive continuous blood pressure monitoring by the ClearSight system during robot-assisted laparoscopic radical prostatectomy.

PubMed

Sakai, Yoko; Yasuo M, Tsutsumi; Oyama, Takuro; Murakami, Chiaki; Kakuta, Nami; Tanaka, Katsuya

2018-01-01

Robot-assisted laparoscopic radical prostatectomy (RALRP) is commonly performed in the surgical treatment of prostate cancer. However, the steep Trendelenburg position (25) and pneumoperitoneum required for this procedure can sometimes cause hemodynamic changes. Although blood pressure is traditionally monitored invasively during RALRP, the ClearSight system (BMEYE, Amsterdam, The Netherlands) enables a totally noninvasive and simple continuous blood pressure and cardiac output monitoring based on finger arterial pressure pulse contour analysis. We therefore investigated whether noninvasive continuous arterial blood pressure measurements using the ClearSight system were comparable to those obtained invasively in patients undergoing RALRP. Ten patients scheduled for RALRP with American Society of Anesthesiologists physical status I-II were included in this study. At each of the seven defined time points, noninvasive and invasive blood pressure measurements were documented and compared in each patient using Bland-Altman analysis. Although the blood pressure measured with the ClearSight system correlated with that measured invasively, a large difference between the values obtained by the two devices was noted. The ClearSight system was unable to detect blood pressure accurately during RALRP, suggesting that blood pressure monitoring using this device alone is not feasible in this small patient population. J. Med. Invest. 65:69-73, February, 2018.

The Efficacy of Low-Level Continuous Positive Airway Pressure for the Treatment of Snoring

PubMed Central

Guzman, Michelle A.; Sgambati, Francis P.; Pho, Huy; Arias, Rafael S.; Hawks, Erin M.; Wolfe, Erica M.; Ötvös, Tamás; Rosenberg, Russell; Dakheel, Riad; Schneider, Hartmut; Kirkness, Jason P.; Smith, Philip L.; Schwartz, Alan R.

2017-01-01

Study Objectives: To assess effects of low-level continuous positive airway pressure (CPAP) on snoring in habitual snorers without obstructive sleep apnea (OSA). Methods: A multicenter prospective in-laboratory reversal crossover intervention trial was conducted between September 2013 and August 2014. Habitual snorers were included if they snored (inspiratory sound pressure level ≥ 40 dBA) for ≥ 30% all sleep breaths on a baseline sleep study (Night 1), and if significant OSA and daytime somnolence were absent. Included participants then underwent a CPAP titration study at 2, 4, or 6 cm H2O (Night 2) to examine snoring responses to step-increases in nasal pressure, a treatment night at optimal pressure (Night 3), followed by baseline night (Night 4). At each pressure, snoring intensity was measured on each breath. Snoring frequency was quantified as a percentage of sleep breaths at thresholds of 40, 45, 50, and 55 dBA. Sleep architecture and OSA severity were characterized using standard measurements. Results: On baseline sleep studies, participants demonstrated snoring at ≥ 40 dBA on 53 ± 3% and ≥ 45 dBA on 35 ± 4% of breaths. Snoring frequency decreased progressively as nasal pressure increased from 0 to 4 cm H2O at each threshold, and plateaued thereafter. CPAP decreased snoring frequency by 67% and 85% at 40 and 45 dBA, respectively. Intervention did not alter sleep architecture and sleep apnea decreased minimally. Conclusions: Low-level CPAP below the range required to treat OSA diminished nocturnal snoring, and produced uniform reduction in nightly noise production below the World Health Organization's limit of 45 dBA. Clinical Trial Registration: ClinicalTrials.gov, identifier: NCT01949584. Citation: Guzman MA, Sgambati FP, Pho H, Arias RS, Hawks EM, Wolfe EM, Ötvös T, Rosenberg R, Dakheel R, Schneider H, Kirkness JP, Smith PL, Schwartz AR. The efficacy of low-level continuous positive airway pressure for the treatment of snoring. J Clin Sleep Med. 2017;13(5):703–711. PMID:28356182

A pilot study of an in-vitro bovine trachea model of the effect of continuous positive airway pressure breathing on airway surface liquid.

PubMed

White, David E; Nates, Roy J; Bartley, Jim

2014-02-06

Continuous positive air pressure (CPAP) users frequently report troublesome symptoms of airway dryness and nasal congestion. Clinical investigations have demonstrated that supplementary humidification reduces these symptoms but the reason for their occurrence remains unexplained. Investigations using human computational air-conditioning models are unable to reproduce or quantify the apparent airway drying experienced during CPAP therapy. The purpose of this study was to determine whether augmented air pressures change overall mucosal airway surface liquid (ASL) water supply and, if so, the extent of this effect. In an original in vitro experimental set up, maximal ASL supply was determined in whole bovine trachea when exposed to simulated tidal breathing stresses over a range of air pressures. At ambient pressure, the maximal supply of ASL was found to compare well to previously published data (31.2 μl/cm2.hr). CPAP pressures from 5 cm H2O above ambient were found to reduce ASL supply by 22%. Statistical analysis (n = 8) showed a significant difference existed between the ambient and CPAP results (p < 0.0001), and that there was no significant variation between all pressurized results (p = 0.716). These findings provide preliminary data that ASL supply is reduced by CPAP therapy which may explain the airway drying symptoms associated with this therapy.

Noninvasive Hemodynamic Measurements During Neurosurgical Procedures in Sitting Position.

PubMed

Schramm, Patrick; Tzanova, Irene; Gööck, Tilman; Hagen, Frank; Schmidtmann, Irene; Engelhard, Kristin; Pestel, Gunther

2017-07-01

Neurosurgical procedures in sitting position need advanced cardiovascular monitoring. Transesophageal echocardiography (TEE) to measure cardiac output (CO)/cardiac index (CI) and stroke volume (SV), and invasive arterial blood pressure measurements for systolic (ABPsys), diastolic (ABPdiast) and mean arterial pressure (MAP) are established monitoring technologies for these kind of procedures. A noninvasive device for continuous monitoring of blood pressure and CO based on a modified Penaz technique (volume-clamp method) was introduced recently. In the present study the noninvasive blood pressure measurements were compared with invasive arterial blood pressure monitoring, and the noninvasive CO monitoring to TEE measurements. Measurements of blood pressure and CO were performed in 35 patients before/after giving a fluid bolus and a change from supine to sitting position, start of surgery, and repositioning from sitting to supine at the end of surgery. Data pairs from the noninvasive device (Nexfin HD) versus arterial line measurements (ABPsys, ABPdiast, MAP) and versus TEE (CO, CI, SV) were compared using Bland-Altman analysis and percentage error. All parameters compared (CO, CI, SV, ABPsys, ABPdiast, MAP) showed a large bias and wide limits of agreement. Percentage error was above 30% for all parameters except ABPsys. The noninvasive device based on a modified Penaz technique cannot replace arterial blood pressure monitoring or TEE in anesthetized patients undergoing neurosurgery in sitting position.

Selective indication for positive airway pressure (PAP) in sleep-related breathing disorders with obstruction

PubMed Central

Stasche, Norbert

2006-01-01

Positive airway pressure (PAP) is the therapy of choice for most sleep-related breathing disorders (SRBD). A variety of PAP devices using positive airway pressure (CPAP, BiPAP, APAP, ASV) must be carefully considered before application. This overview aims to provide criteria for choosing the optimal PAP device according to severity and type of sleep-related breathing disorder. In addition, the range of therapeutic applications, constraints and side effects as well as alternative methods to PAP will be discussed. This review is based on an analysis of current literature and clinical experience. The data is presented from an ENT-sleep-laboratory perspective and is designed to help the ENT practitioner initiate treatment and provide support. Different titration methods, current devices and possible applications will be described. In addition to constant pressure devices (CPAP), most commonly used for symptomatic obstructive sleep apnoea (OSA) without complicating conditions, BiPAP models will be introduced. These allow two different positive pressure settings and are thus especially suitable for patients with cardiopulmonary diseases or patients with pressure intolerance, increasing compliance in this subgroup considerably. Compliance can also be increased in patients during first night of therapy, patients with highly variable pressure demands or position-dependent OSA, by using self-regulating Auto-adjust PAP devices (Automatic positive airway pressure, APAP). Patients with Cheyne-Stokes breathing, a subtype of central sleep apnoea, benefit from adaptive servo-ventilation (ASV), which analyzes breathing patterns continually and adjusts the actual ventilation pressure accordingly. This not only reduces daytime sleepiness, but can also influence heart disease positively. Therapy with positive airway pressure is very effective in eliminating obstruction-related sleep diseases and symptoms. However, because therapy is generally applied for life, the optimal PAP device must be carefully selected, taking into account side effects that influence compliance. PMID:22073075

Passive continuous positive airway pressure ventilation during cardiopulmonary resuscitation: a randomized cross-over manikin simulation study.

PubMed

Winkler, Bernd E; Muellenbach, Ralf M; Wurmb, Thomas; Struck, Manuel F; Roewer, Norbert; Kranke, Peter

2017-02-01

While controlled ventilation is most frequently used during cardiopulmonary resuscitation (CPR), the application of continuous positive airway pressure (CPAP) and passive ventilation of the lung synchronously with chest compressions and decompressions might represent a promising alternative approach. One benefit of CPAP during CPR is the reduction of peak airway pressures and therefore a potential enhancement in haemodynamics. We therefore evaluated the tidal volumes and airway pressures achieved during CPAP-CPR. During CPR with the LUCAS™ 2 compression device, a manikin model was passively ventilated at CPAP levels of 5, 10, 20 and 30 hPa with the Boussignac tracheal tube and the ventilators Evita ® V500, Medumat ® Transport, Oxylator ® EMX, Oxylog ® 2000, Oxylog ® 3000, Primus ® and Servo ® -i as well as the Wenoll ® diver rescue system. Tidal volumes and airway pressures during CPAP-CPR were recorded and analyzed. Tidal volumes during CPAP-CPR were higher than during compression-only CPR without positive airway pressure. The passively generated tidal volumes increased with increasing CPAP levels and were significantly influenced by the ventilators used. During ventilation at 20 hPa CPAP via a tracheal tube, the mean tidal volumes ranged from 125 ml (Medumat ® ) to 309 ml (Wenoll ® ) and the peak airway pressures from 23 hPa (Primus ® ) to 49 hPa (Oxylog ® 3000). Transport ventilators generated lower tidal volumes than intensive care ventilators or closed-circuit systems. Peak airway pressures during CPAP-CPR were lower than those during controlled ventilation CPR reported in literature. High peak airway pressures are known to limit the applicability of ventilation via facemask or via supraglottic airway devices and may adversely affect haemodynamics. Hence, the application of ventilators generating high tidal volumes with low peak airway pressures appears desirable during CPAP-CPR. The limited CPAP-CPR capabilities of transport ventilators in our study might be prerequisite for future developments of transport ventilators.

Randomized controlled trial comparing nasal intermittent positive pressure ventilation and nasal continuous positive airway pressure in premature infants after tracheal extubation.

PubMed

Komatsu, Daniela Franco Rizzo; Diniz, Edna Maria de Albuquerque; Ferraro, Alexandre Archanjo; Ceccon, Maria Esther Jurvest Rivero; Vaz, Flávio Adolfo Costa

2016-09-01

To analyze the frequency of extubation failure in premature infants using conventional mechanical ventilation (MV) after extubation in groups subjected to nasal intermittent positive pressure ventilation (nIPPV) and continuous positive airway pressure (nCPAP). Seventy-two premature infants with respiratory failure were studied, with a gestational age (GA) ≤ 36 weeks and birth weight (BW) > 750 g, who required tracheal intubation and mechanical ventilation. The study was controlled and randomized in order to ensure that the members of the groups used in the research were chosen at random. Randomization was performed at the time of extubation using sealed envelopes. Extubation failure was defined as the need for re-intubation and mechanical ventilation during the first 72 hours after extubation. Among the 36 premature infants randomized to nIPPV, six (16.6%) presented extubation failure in comparison to 11 (30.5%) of the 36 premature infants randomized to nCPAP. There was no statistical difference between the two study groups regarding BW, GA, classification of the premature infant, and MV time. The main cause of extubation failure was the occurrence of apnea. Gastrointestinal and neurological complications did not occur in the premature infants participating in the study. We found that, despite the extubation failure of the group of premature infants submitted to nIPPV being numerically smaller than in premature infants submitted to nCPAP, there was no statistically significant difference between the two modes of ventilatory support after extubation.

Intramuscular pressure and torque during isometric, concentric and eccentric muscular activity

NASA Technical Reports Server (NTRS)

Styf, J.; Ballard, R.; Aratow, M.; Crenshaw, A.; Watenpaugh, D.; Hargens, A. R.

1995-01-01

Intramuscular pressures, electromyography (EMG) and torque generation during isometric, concentric and eccentric maximal isokinetic muscle activity were recorded in 10 healthy volunteers. Pressure and EMG activity were continuously and simultaneously measured side by side in the tibialis anterior and soleus muscles. Ankle joint torque and position were monitored continuously by an isokinetic dynamometer during plantar flexion and dorsiflexion of the foot. The increased force generation during eccentric muscular activity, compared with other muscular activity, was not accompanied by higher intramuscular pressure. Thus, this study demonstrated that eccentric muscular activity generated higher torque values for each increment of intramuscular pressure. Intramuscular pressures during antagonistic co-activation were significantly higher in the tibilis anterior muscle (42-46% of maximal agonistic activity) compared with the soleus muscle (12-29% of maximal agonistic activity) and was largely due to active recruitment of muscle fibers. In summary, eccentric muscular activity creates higher torque values with no additional increase of the intramuscular pressure compared with concentric and isometric muscular activity.

Letter to editor: Blood pressure, hypertension and lead exposure.

PubMed

Yang, Wen-Yi; Staessen, Jan A

2018-02-19

A significant association of office diastolic blood pressure with low-level blood lead exposure was reported in a Brazilian adult population. However, caution should be taken to interpret these results. The multivariable-adjusted association with blood pressure was positive for diastolic blood pressure, but inverse for systolic blood pressure. The association sizes were infinitesimal without clinical relevance. The outcome measures, i.e. blood pressure and the prevalence of hypertension were analysed across categories of the blood lead distribution - not in relation to blood lead as continuous variable. Blood pressure was the average of two oscillometric office readings, whereas ambulatory monitoring is the state-of-the-art.

An observational study of the effectiveness of alternative care providers in the management of obstructive sleep apnea.

PubMed

Pendharkar, Sachin R; Dechant, Anthony; Bischak, Diane P; Tsai, Willis H; Stevenson, Ann-Marie; Hanly, Patrick J

2016-04-01

Alternative care providers have been proposed as a substitute for physician-based management of obstructive sleep apnea. The purpose of this study was to describe the clinical course of patients with a new diagnosis of obstructive sleep apnea who were treated with continuous positive airway pressure and followed by alternative care providers at a tertiary care sleep clinic. It was hypothesized that care by alternative care providers would result in improvement of daytime sleepiness and satisfactory treatment adherence, and that a specific number of follow-up visits could be identified after which clinical outcomes no longer improved. The Epworth Sleepiness Scale score was measured for each patient at baseline and at each alternative care provider visit. Patients were discharged when they demonstrated a significant improvement in sleepiness and were adherent to therapy. The Epworth Sleepiness Scale score decreased by 3.9 points from baseline to discharge. Patients with three or more visits required more follow-up time to achieve the same clinical improvement as those with only two visits. Continuous positive airway pressure adherence was comparable to previous studies of physician-led care and improved with ongoing alternative care provider follow-up. The current results suggest that clinical care by alternative care providers leads to continued improvements in sleepiness in patients with obstructive sleep apnea who are treated with continuous positive airway pressure, and that a minority of patients require longer follow-up to achieve a satisfactory clinical response to therapy. © 2015 European Sleep Research Society.

Effects of Continuous Positive Airway Pressure on Neurocognitive Function in Obstructive Sleep Apnea Patients: The Apnea Positive Pressure Long-term Efficacy Study (APPLES)

PubMed Central

Kushida, Clete A.; Nichols, Deborah A.; Holmes, Tyson H.; Quan, Stuart F.; Walsh, James K.; Gottlieb, Daniel J.; Simon, Richard D.; Guilleminault, Christian; White, David P.; Goodwin, James L.; Schweitzer, Paula K.; Leary, Eileen B.; Hyde, Pamela R.; Hirshkowitz, Max; Green, Sylvan; McEvoy, Linda K.; Chan, Cynthia; Gevins, Alan; Kay, Gary G.; Bloch, Daniel A.; Crabtree, Tami; Dement, William C.

2012-01-01

Study Objective: To determine the neurocognitive effects of continuous positive airway pressure (CPAP) therapy on patients with obstructive sleep apnea (OSA). Design, Setting, and Participants: The Apnea Positive Pressure Long-term Efficacy Study (APPLES) was a 6-month, randomized, double-blind, 2-arm, sham-controlled, multicenter trial conducted at 5 U.S. university, hospital, or private practices. Of 1,516 participants enrolled, 1,105 were randomized, and 1,098 participants diagnosed with OSA contributed to the analysis of the primary outcome measures. Intervention: Active or sham CPAP Measurements: Three neurocognitive variables, each representing a neurocognitive domain: Pathfinder Number Test-Total Time (attention and psychomotor function [A/P]), Buschke Selective Reminding Test-Sum Recall (learning and memory [L/M]), and Sustained Working Memory Test-Overall Mid-Day Score (executive and frontal-lobe function [E/F]) Results: The primary neurocognitive analyses showed a difference between groups for only the E/F variable at the 2 month CPAP visit, but no difference at the 6 month CPAP visit or for the A/P or L/M variables at either the 2 or 6 month visits. When stratified by measures of OSA severity (AHI or oxygen saturation parameters), the primary E/F variable and one secondary E/F neurocognitive variable revealed transient differences between study arms for those with the most severe OSA. Participants in the active CPAP group had a significantly greater ability to remain awake whether measured subjectively by the Epworth Sleepiness Scale or objectively by the maintenance of wakefulness test. Conclusions: CPAP treatment improved both subjectively and objectively measured sleepiness, especially in individuals with severe OSA (AHI > 30). CPAP use resulted in mild, transient improvement in the most sensitive measures of executive and frontal-lobe function for those with severe disease, which suggests the existence of a complex OSA-neurocognitive relationship. Clinical Trial Information: Registered at clinicaltrials.gov. Identifier: NCT00051363. Citation: Kushida CA; Nichols DA; Holmes TH; Quan SF; Walsh JK; Gottlieb DJ; Simon RD; Guilleminault C; White DP; Goodwin JL; Schweitzer PK; Leary EB; Hyde PR; Hirshkowitz M; Green S; McEvoy LK; Chan C; Gevins A; Kay GG; Bloch DA; Crabtree T; Demen WC. Effects of continuous positive airway pressure on neurocognitive function in obstructive sleep apnea patients: the Apnea Positive Pressure Long-term Efficacy Study (APPLES). SLEEP 2012;35(12):1593-1602. PMID:23204602

Effects of body position and sex group on tongue pressure generation.

PubMed

Dietsch, Angela M; Cirstea, Carmen M; Auer, Ed T; Searl, Jeff P

2013-11-01

Fine control of orofacial musculature is necessary to precisely accelerate and decelerate the articulators across exact distances for functional speech and coordinated swallows (Amerman & Parnell, 1990; Benjamin, 1997; Kent, Duffy, Slama, Kent, & Clift, 2001). Enhanced understanding of neural control for such movements could clarify the nature of and potential remediation for some dysarthrias and other orofacial myofunctional impairments. Numerous studies have measured orolingual force and accuracy during speech and nonspeech tasks, but have focused on young adults, maximum linguapalatal pressures, and upright positioning (O'Day, Frank, Montgomery, Nichols, & McDade, 2005; Solomon & Munson, 2004; Somodi, Robin, & Luschei, 1995; Youmans, Youmans, & Stierwalt, 2009). Patients' medical conditions or testing procedures such as concurrent neuroimaging may preclude fully upright positioning during oral motor assessments in some cases. Since judgments about lingual strength and coordination can influence clinical decisions regarding the functionality of swallowing and speech, it is imperative to understand any effects of body positioning differences. In addition, sex differences in the control of such tasks are not well defined. Therefore, this study evaluated whether pressures exerted during tongue movements differ in upright vs. supine body position in healthy middle-aged men and women. Twenty healthy middle-aged adults compressed small air-filled plastic bulbs in the oral cavity at predetermined fractions of task-specific peak pressure in a randomized block design. Tasks including phoneme repetitions and nonspeech isometric contractions were executed in upright and supine positions. Participants received continuous visual feedback regarding targets and actual exerted pressures. Analyses compared average pressure values for each subject, task, position, and effort level. Speech-like and nonspeech tongue pressures did not differ significantly across body position or sex groups. Pressure matching was significantly less accurate at higher percentages of maximum pressure for both tasks. These results provide preliminary comparative data for the clinical assessment of individuals with orofacial myofunctional and neurological disorders.

Practice Parameters for the Use of Autotitrating Continuous Positive Airway Pressure Devices for Titrating Pressures and Treating Adult Patients with Obstructive Sleep Apnea Syndrome: An Update for 2007

PubMed Central

Morgenthaler, Timothy I.; Aurora, R. Nisha; Brown, Terry; Zak, Rochelle; Alessi, Cathy; Boehlecke, Brian; Chesson, Andrew L.; Friedman, Leah; Kapur, Vishesh; Maganti, Rama; Owens, Judith; Pancer, Jeffrey; Swick, Todd J.

2008-01-01

These practice parameters are an update of the previously published recommendations regarding the use of autotitrating positive airway pressure (APAP) devices for titrating pressures and treating adult patients with obstructive sleep apnea syndrome. Continuous positive airway pressure (CPAP) at an effective setting verified by attended polysomnography is a standard treatment for obstructive sleep apnea (OSA). APAP devices change the treatment pressure based on feedback from various patient measures such as airflow, pressure fluctuations, or measures of airway resistance. These devices may aid in the pressure titration process, address possible changes in pressure requirements throughout a given night and from night to night, aid in treatment of OSA when attended CPAP titration has not or cannot be accomplished, or improve patient comfort. A task force of the Standards of Practice Committee of the American Academy of Sleep Medicine has reviewed the literature published since the 2002 practice parameter on the use of APAP. Current recommendations follow: (1) APAP devices are not recommended to diagnose OSA; (2) patients with congestive heart failure, patients with significant lung disease such as chronic obstructive pulmonary disease; patients expected to have nocturnal arterial oxyhemoglobin desaturation due to conditions other than OSA (e.g., obesity hypoventilation syndrome); patients who do not snore (either naturally or as a result of palate surgery); and patients who have central sleep apnea syndromes are not currently candidates for APAP titration or treatment; (3) APAP devices are not currently recommended for split-night titration; (4) certain APAP devices may be used during attended titration with polysomnography to identify a single pressure for use with standard CPAP for treatment of moderate to severe OSA; (5) certain APAP devices may be initiated and used in the self-adjusting mode for unattended treatment of patients with moderate to severe OSA without significant comorbidities (CHF, COPD, central sleep apnea syndromes, or hypoventilation syndromes); (6) certain APAP devices may be used in an unattended way to determine a fixed CPAP treatment pressure for patients with moderate to severe OSA without significant comorbidities (CHF, COPD, central sleep apnea syndromes, or hypoventilation syndromes); (7) patients being treated with fixed CPAP on the basis of APAP titration or being treated with APAP must have close clinical follow-up to determine treatment effectiveness and safety; and (8) a reevaluation and, if necessary, a standard attended CPAP titration should be performed if symptoms do not resolve or the APAP treatment otherwise appears to lack efficacy. Citation: Morgenthaler TI; Aurora RN; Brown T; Zak R; Alessi C; Boehlecke B; Chesson AL; Friedman L; Kapur V; Maganti R; Owens J; Pancer J; Swick TJ; Standards of Practice Committee of the AASM. Practice parameters for the use of autotitrating continuous positive airway pressure devices for titrating pressures and treating adult patients with obstructive sleep apnea syndrome: An update for 2007. SLEEP 2008;31(1):141-147. PMID:18220088

The effect of continuous positive airway pressure on middle ear pressure.

PubMed

Lin, Fred Y; Gurgel, Richard K; Popelka, Gerald R; Capasso, Robson

2012-03-01

While continuous positive airway pressure (CPAP) is commonly used for obstructive sleep apnea treatment, its effect on middle ear pressure is unknown. The purpose of this study was to measure the effect of CPAP on middle ear pressure and describe the correlation between CPAP levels and middle ear pressures. Retrospective review of normal tympanometry values and a prospective cohort evaluation of subjects' tympanometric values while using CPAP at distinct pressure levels. A total of 3,066 tympanograms were evaluated to determine the normal range of middle ear pressures. Ten subjects with no known history of eustachian tube dysfunction or obstructive sleep apnea had standard tympanometry measurements while wearing a CPAP device. Measurements were taken at baseline and with CPAP air pressures of 0, 5, 10, and 15 cm H(2)O. The percentage of normal control patients with middle ear pressures above 40 daPa was 0.03%. In the study population, prior to a swallowing maneuver to open the eustachian tube, average middle ear pressures were 21.67 daPa, 22.63 daPa, 20.42, daPa, and 21.58 daPa with CPAP pressures of 0, 5, 10, and 15 cm H(2) 0, respectively. After swallowing, average middle ear air pressures were 18.83 daPa, 46.75 daPa, 82.17 daPa, and 129.17 daPa with CPAP pressures of 0, 5, 10, and 15 cm H(2)0, respectively. The postswallow Pearson correlation coefficient correlating CPAP and middle ear pressures was 0.783 (P < 0.001). Middle ear air pressure is directly proportional to CPAP air pressure in subjects with normal eustachian tube function. Middle ear pressure reaches supraphysiologic levels at even minimal CPAP levels. Although further investigation is necessary, there may be otologic implications for patients who are chronically CPAP dependent. These findings may also influence the perioperative practice of otologic and skull base surgeons. Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.

Pneumocephalus with BiPAP use after transsphenoidal surgery☆,☆☆,★

PubMed Central

Kopelovich, Jonathan C.; de la Garza, Gabriel O.; Greenlee, Jeremy D.W.; Graham, Scott M.; Udeh, Chiedozie I.; O'Brien, Erin K.

2013-01-01

While the benefits of continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BiPAP) for patients with obstructive sleep apnea are well described, reports in the literature of complications from its use are rare. A patient who received postoperative BiPAP after undergoing transsphenoidal craniopharyngioma resection developed severe pneumocephalus and unplanned intensive care unit admission. Although the pneumocephalus resolved with conservative management over two weeks, we propose caution in the use of CPAP postoperatively in patients undergoing procedures of the head and neck. PMID:22626688

Reduced pressure for fewer pressure ulcers: can real-time feedback of interface pressure optimise repositioning in bed?

PubMed

Gunningberg, Lena; Carli, Cheryl

2016-10-01

The aim of this study was to (i) describe registered nurses' and assistant nurses' repositioning skills with regard to their existing attitudes to and theoretical knowledge of pressure ulcer (PU) prevention, and (ii) evaluate if the continuous bedside pressure mapping (CBPM) system provides staff with a pedagogic tool to optimise repositioning. A quantitative study was performed using a descriptive, comparative design. Registered nurses (n = 19) and assistant nurses (n = 33) worked in pairs, and were instructed to place two volunteers (aged over 70 years) in the best pressure-reducing position (lateral and supine), first without viewing the CBPM monitor and then again after feedback. In total, 240 positionings were conducted. The results show that for the same person with the same available pressure-reducing equipment, the peak pressure varied considerably between nursing pairs. Reducing pressure in the lateral position appeared to be the most challenging. Peak pressures were significantly reduced, based on visual feedback from the CBPM monitor. The number of preventive interventions also increased, as well as patients' comfort. For the nurses as a group, the knowledge score was 59·7% and the attitude score was 88·8%. Real-time visual feedback of pressure points appears to provide another dimension to complement decision making with respect to PU prevention. © 2014 The Authors. International Wound Journal © 2014 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

Air Pump-Assisted Graft Centration, Graft Edge Unfolding, and Graft Uncreasing in Young Donor Graft Pre-Descemet Endothelial Keratoplasty.

PubMed

Jacob, Soosan; Narasimhan, Smita; Agarwal, Amar; Agarwal, Athiya; A I, Saijimol

2017-08-01

To assess an air pump-assisted technique for graft centration, graft edge unfolding, and graft uncreasing while performing pre-Descemet endothelial keratoplasty (PDEK) using young donor grafts. Continuous pressurized air infusion was used for graft centration, graft edge unfolding, and graft unwrinkling. Ten eyes of 10 patients underwent PDEK with donors aged below 40 years. In all eyes, the donor scrolled into tight scrolls. In all cases, the air pump-assisted technique was effective in positioning and centering the graft accurately and in straightening infolded graft edges and smoothing out graft creases and wrinkles. Endothelial cell loss was 38.6%. Postoperative best-corrected visual acuity at 6 months was 0.66 ± 0.25 in decimal equivalent. Continuous pressurized air infusion acted as a third hand providing a continuous pressure head that supported the graft and prevented graft dislocation as well as anterior chamber collapse during intraocular maneuvering. Adequate maneuvering space was available in all cases, and bleeding, if any, was tamponaded successfully in all cases. Although very young donor grafts may be used for PDEK, they are difficult to center and unroll completely before floating against host stroma. An air pump-assisted technique using continuous pressurized air infusion allows successful final graft positioning even with very young donor corneas. It thus makes surgery easier as several key steps are made easier to handle. It additionally helps in tamponading hemorrhage during peripheral iridectomy, increasing surgical space, preventing fluctuations in the anterior chamber depth, and promoting graft adherence.

Obstructive sleep apnea syndrome, continuous positive airway pressure and treatment of hypertension.

PubMed

Floras, John S

2015-09-15

Obstructive sleep apnea (OSA), present in ~15% of the general population, increases the risks of stroke, heart failure, and premature death. Importantly, individuals with cardiovascular disease have a higher prevalence yet they often have few symptoms to alert clinicians to its presence. OSA with an apnea-hypopnea index (AHI) ≥15 events/hour is present in ≥30% of patients with primary hypertension and in up to 80% of those with drug resistant hypertension, suggesting that the neural, hormonal, inflammatory and vascular cascades triggered by OSA may elevate blood pressure chronically. The purpose of this review is to summarize: (1) the epidemiology of OSA and its relation to cardiovascular risk; (2) potential mechanisms by which OSA could promote conditions known to increase the risk of hypertension or contribute to its development and progression; (3) evidence for and against a pro-hypertensive effect of OSA; and, (4) the impact of treatment with continuous positive airway pressure (CPAP) on blood pressure and blood pressure-related morbidities. The prevailing view that the effect of treatment on blood pressure is modest arises from the inability of most contemporary technology to measure accurately the true impact of CPAP on OSA-entrained surges in nocturnal blood pressure. Moreover the exclusive focus on blood pressure, as if this is the principal determinant of cardiovascular event rates in this population, is naïve. The capacity to reduce cardiovascular risk by treating OSA with CPAP likely transcends a simple blood pressure effect; formal testing of this hypothesis will require adequately powered randomized clinical trials. Copyright © 2015 Elsevier B.V. All rights reserved.

Titration effectiveness of two autoadjustable continuous positive airway pressure devices driven by different algorithms in patients with obstructive sleep apnoea.

PubMed

Damiani, Mario Francesco; Quaranta, Vitaliano Nicola; Tedeschi, Ersilia; Drigo, Riccardo; Ranieri, Teresa; Carratù, Pierluigi; Resta, Onofrio

2013-08-01

Nocturnal application of continuous positive airway pressure (CPAP) is the standard treatment for patients with obstructive sleep apnoea (OSA). Determination of the therapeutic pressure (CPAP titration) is usually performed by a technician in the sleep laboratory during attended polysomnography. One possible alternative to manual titration is automated titration. Indeed, during the last 15 years, devices have been developed that deliver autoadjustable CPAP (A-CPAP). The aim of the present study was to compare the titration effectiveness of two A-CPAP devices using different flow-based algorithms in patients with OSA. This is a randomized study; 79 subjects underwent two consecutive unattended home A-CPAP titration nights with two different devices (Autoset Resmed; Remstar Auto Respironics); during the third and the fourth night, patients underwent portable monitoring in the sleep laboratory during fixed CPAP at the A-CPAP recommended pressure. Bland Altman plots showed good agreement between the recommended median and maximal pressure levels obtained with the two devices. A significant improvement was observed in all the sleep parameters by both A-CPAP machines to a similar degree. It was observed that the two A-CPAP devices using different algorithms are equally effective in initial titration of CPAP. © 2013 The Authors. Respirology © 2013 Asian Pacific Society of Respirology.

Effects of Continuous Positive Airway Pressure on Middle Ear Pressure and Acoustic Stapedial Reflex.

PubMed

Li, Jinrang; Li, Keliang

2016-08-01

This study investigated the effects of continuous positive airway pressure (CPAP) on middle ear pressure and acoustic stapedial reflex and the correlation between CPAP and middle ear pressure. Prospective cohort study. Tertiary hospitals. Fifty patients with obstructive sleep apnea-hypopnea syndrome were assigned to the study group, and 50 healthy volunteers were assigned to the control group. The subjects underwent standard tympanometry while wearing a CPAP device (ie, simulated CPAP treatment), which was set to 0, 5, 10, and 15 cm H2O, respectively. Tympanometry was performed before and after swallowing at each pressure of CPAP treatment. The mean middle ear pressures were 21.2, 22.6, 22.7, and 23.4 daPa (before swallowing) and 21.6, 42.6, 81.4, and 118.6 daPa (after swallowing) in the study group and 17.6, 18.7, 19.5, and 20.8 daPa (before swallowing) and 17.7, 44.2, 85.6, and 120.5 daPa (after swallowing) in the control group at the CPAPs of 0, 5, 10, and 15 cm H2O, respectively. While the CPAPs were at 0 and 15 cm H2O, the stapedial muscle reflex at 1.0 kHz did not have a significant difference between the 2 groups (χ(2) = 0.521, P = .470). The Pearson correlation coefficient of the CPAP pressure and the middle ear pressure after swallowing was 0.812 (P < .001). CPAP affected middle ear pressure and was directly proportional to the pressure of the CPAP. However, CPAP treatment had no significant effect on stapedial muscle reflex. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

Is increased positive end-expiratory pressure the culprit? Autoresuscitation in a 44-year-old man after prolonged cardiopulmonary resuscitation: a case report.

PubMed

Hagmann, Henning; Oelmann, Katrin; Stangl, Robert; Michels, Guido

2016-12-20

The phenomenon of autoresuscitation is rare, yet it is known to most emergency physicians. However, the pathophysiology of the delayed return of spontaneous circulation remains enigmatic. Among other causes hyperinflation of the lungs and excessively high positive end-expiratory pressure have been suggested, but reports including cardiopulmonary monitoring during cardiopulmonary resuscitation are scarce to support this hypothesis. We report a case of autoresuscitation in a 44-year-old white man after 80 minutes of advanced cardiac life support accompanied by continuous capnometry and repeated evaluation by ultrasound and echocardiography. After prolonged cardiopulmonary resuscitation, refractory electromechanical dissociation on electrocardiogram and ventricular akinesis were recorded. In addition, a precipitous drop in end-tidal partial pressure of carbon dioxide was noted and cardiopulmonary resuscitation was discontinued. Five minutes after withdrawal of all supportive measures his breathing resumed and a perfusing rhythm ensued. Understanding the underlying pathophysiology of autoresuscitation is hampered by a lack of reports including extensive cardiopulmonary monitoring during cardiopulmonary resuscitation in a preclinical setting. In this case, continuous capnometry was combined with repetitive ultrasound evaluation, which ruled out most assumed causes of autoresuscitation. Our observation of a rapid decline in end-tidal partial pressure of carbon dioxide supports the hypothesis of increased intrathoracic pressure. Continuous capnometry can be performed easily during cardiopulmonary resuscitation, also in a preclinical setting. Knowledge of the pathophysiologic mechanisms may lead to facile interventions to be incorporated into cardiopulmonary resuscitation algorithms. A drop in end-tidal partial pressure of carbon dioxide, for example, might prompt disconnection of the ventilation to allow left ventricular filling. Further reports and research on this topic are encouraged.

Treatment of sleep-disordered breathing with positive airway pressure devices: technology update.

PubMed

Johnson, Karin Gardner; Johnson, Douglas Clark

2015-01-01

Many types of positive airway pressure (PAP) devices are used to treat sleep-disordered breathing including obstructive sleep apnea, central sleep apnea, and sleep-related hypoventilation. These include continuous PAP, autoadjusting CPAP, bilevel PAP, adaptive servoventilation, and volume-assured pressure support. Noninvasive PAP has significant leak by design, which these devices adjust for in different manners. Algorithms to provide pressure, detect events, and respond to events vary greatly between the types of devices, and vary among the same category between companies and different models by the same company. Many devices include features designed to improve effectiveness and patient comfort. Data collection systems can track compliance, pressure, leak, and efficacy. Understanding how each device works allows the clinician to better select the best device and settings for a given patient. This paper reviews PAP devices, including their algorithms, settings, and features.

A High-Value, Low-Cost Bubble Continuous Positive Airway Pressure System for Low-Resource Settings: Technical Assessment and Initial Case Reports

PubMed Central

Brown, Jocelyn; Machen, Heather; Kawaza, Kondwani; Mwanza, Zondiwe; Iniguez, Suzanne; Lang, Hans; Gest, Alfred; Kennedy, Neil; Miros, Robert; Richards-Kortum, Rebecca; Molyneux, Elizabeth; Oden, Maria

2013-01-01

Acute respiratory infections are the leading cause of global child mortality. In the developing world, nasal oxygen therapy is often the only treatment option for babies who are suffering from respiratory distress. Without the added pressure of bubble Continuous Positive Airway Pressure (bCPAP) which helps maintain alveoli open, babies struggle to breathe and can suffer serious complications, and frequently death. A stand-alone bCPAP device can cost $6,000, too expensive for most developing world hospitals. Here, we describe the design and technical evaluation of a new, rugged bCPAP system that can be made in small volume for a cost-of-goods of approximately $350. Moreover, because of its simple design—consumer-grade pumps, medical tubing, and regulators—it requires only the simple replacement of a <$1 diaphragm approximately every 2 years for maintenance. The low-cost bCPAP device delivers pressure and flow equivalent to those of a reference bCPAP system used in the developed world. We describe the initial clinical cases of a child with bronchiolitis and a neonate with respiratory distress who were treated successfully with the new bCPAP device. PMID:23372661

Microclimate is an independent risk factor for the development of intraoperatively acquired pressure ulcers in the park-bench position: A prospective observational study.

PubMed

Yoshimura, Mine; Nakagami, Gojiro; Iizaka, Shinji; Yoshida, Mikako; Uehata, Yoko; Kohno, Michihiro; Kasuya, Yusuke; Mae, Tomoko; Yamasaki, Takashi; Sanada, Hiromi

2015-01-01

Preventing pressure ulcers is important in patients undergoing procedures in the park-bench position. We hypothesized that the microclimate around the skin is a significant risk factor for developing pressure ulcers. This research continuously assessed factors of the microclimate in terms of skin temperature and perspiration as well as the interface pressure in order to determine whether the microclimate is an independent risk factor for the development of park-bench position-related pressure ulcers (PBP-PUs). A prospective observational study was conducted among patients undergoing elective surgery in the park-bench position at a general hospital in the metropolitan area of Japan between April and November 2014. Factors of the microclimate, including skin temperature and perspiration, in addition to the interface pressure were continuously measured throughout surgery. Twenty-nine patients were analyzed (mean age 44.4 ± 13.2 years, male 44.8%). Of these 29 patients, seven (24.1%) developed Category I PBP-PUs. The change in skin temperature from baseline to the end of surgery (2.7 ± 0.3 °C vs. 1.9 ± 0.8 °C) and the average peak pressure (119.1 ± 36.8 mmHg vs. 94.5 ± 23.1 mmHg) were significantly higher in the patients with PBP-PUs than in those without PBP-PUs. There were no significant differences in the amount of perspiration between the two groups. A hierarchical logistic regression analysis showed that the change in skin temperature was significantly related to the development of PBP-PUs (unit = 0.1 °C: odds ratio 1.44, 95% confidential interval 1.09-2.33) when adjusted for the average peak pressure and length of surgery. Our results suggest that a change in skin temperature toward a higher value is an independent risk factor for the development of PBP-PUs. Proper intraoperative management of skin temperature may therefore be a promising candidate as a preventive method against PBP-PU development. © 2015 by the Wound Healing Society.

Technology for noninvasive mechanical ventilation: looking into the black box

PubMed Central

Navajas, Daniel; Montserrat, Josep M.

2016-01-01

Current devices for providing noninvasive respiratory support contain sensors and built-in intelligence for automatically modifying ventilation according to the patient's needs. These devices, including automatic continuous positive airway pressure devices and noninvasive ventilators, are technologically complex and offer a considerable number of different modes of ventilation and setting options, the details of which are sometimes difficult to capture by the user. Therefore, better predicting and interpreting the actual performance of these ventilation devices in clinical application requires understanding their functioning principles and assessing their performance under well controlled bench test conditions with simulated patients. This concise review presents an updated perspective of the theoretical basis of intelligent continuous positive airway pressure and noninvasive ventilation devices, and of the tools available for assessing how these devices respond under specific ventilation phenotypes in patients requiring breathing support. PMID:27730162

Driving ability in sleep apnoea patients before and after CPAP treatment: evaluation on a road safety platform.

PubMed

Mazza, S; Pépin, J-L; Naëgelé, B; Rauch, E; Deschaux, C; Ficheux, P; Lévy, P

2006-11-01

Sleepiness is considered to be the major cause of increased traffic accidents in patients with obstructive sleep apnoea syndrome (OSAS). Until now, OSAS patients' driving ability has been assessed using driving simulators, but no assessment in a more natural driving environment has been carried out to date. The aim of the present study was to evaluate driving parameters in OSAS and in controls on a road safety platform, and to compare them with attentional in-laboratory measures before and after continuous positive airway pressure treatment. The parameters measured were: reaction time; distance to stop and number of collisions on the platform; maintenance of wakefulness; and sustained, selective and divided attention in laboratory. Patients exhibited much longer reaction times than controls, leading to a lengthening of the vehicle's stopping distance of 8.8 m at 40 km.h(-1) and to twice the number of collisions. Patients did not demonstrate objective sleepiness or selective and sustained attention deficits. Divided attention deficits were found. However, they did not allow the prediction of real driving impairment. After CPAP treatment, there was no longer any difference between patients and controls regarding driving and attention performances. Driving abilities are significantly impaired in obstructive sleep apnoea syndrome. After continuous positive airway pressure treatment, deficits were normalised. This stresses the importance of evaluating attentional parameters in apnoeic patients and of offering continuous positive airway pressure treatment even to non-sleepy subjects.

GH-secreting pituitary macroadenoma (acromegaly) associated with progressive dental malocclusion and refractory CPAP treatment.

PubMed

Miranda-Rius, Jaume; Brunet-LLobet, Lluís; Lahor-Soler, Eduard; de Dios-Miranda, David; Giménez-Rubio, Josep Anton

2017-05-10

A link between progressive dental malocclusion, the use of a continuous positive airway pressure mask and GH-secreting pituitary macroadenoma (acromegaly) has not been previously reported. The present clinicopathological analysis stresses that tooth malposition should not be seen exclusively as a local process. A 62-year-old caucasian man with no relevant medical history reported difficulty chewing food and perceived voice alteration during his annual periodontal check-up. He also referred stiffness of the tongue, face, and submandibular area. The patient had been diagnosed with obstructive sleep apnea syndrome two years previously, since when he had worn a continuous positive airway pressure device during sleep. Exploration of the occlusion revealed significant changes: an atypical left lateral and anterior open bite with major buccoversion of teeth 33, 34, 35, 36. Inspection of the soft tissue revealed only macroglossia, although external palpation indicated a subcutaneous stiffness of the submandibular area. General analytical tests, including hormone profiles, and magnetic resonance imaging confirmed the diagnosis of acromegaly induced by a pituitary adenoma. Intrasellar tumor resection via transsphenoidal approach was performed. After surgery, the patient already noted a marked improvement of all symptoms associated with the acromegaly. Desaturation data also evolved favourably and the pulmonologist advised the patient to abandon the continuous positive airway pressure treatment. Progressive dental malocclusion may be associated with a systemic disease and the use of a nasal mask with premaxillary support may distort the diagnosis of acromegaly.

Hemodynamic differences between continual positive and two types of negative pressure ventilation.

PubMed

Lockhat, D; Langleben, D; Zidulka, A

1992-09-01

In seven anesthetized dogs, ventilated with matching lung volumes, tidal volumes, and respiratory rates, we compared the effects on cardiac output (CO), arterial venous oxygen saturation difference (SaO2 - SVO2), and femoral and inferior vena cava pressure (1) intermittent positive pressure ventilation with positive end-expiratory pressure (CPPV); (2) iron-lung ventilation with negative end-expiratory pressure (ILV-NEEP); (3) grid and wrap ventilation with NEEP applied to the thorax and upper abdomen (G&W-NEEP). The values of CO and SaO2 - SVO2 with ILV-NEEP were similar to those with CPPV. However, with G&W-NEEP as compared with ILV-NEEP, mean CO was greater (2.9 versus 2.6 L/min, p = 0.02) and mean (SaO2 - SVO2) was lower (26.6% versus 28.3%, p = NS). Mean PFEM-IVC was higher with G&W-NEEP than with the other types of ventilation. We conclude that (1) ILV-NEEP is hemodynamically equivalent to CPPV and (2) G&W-NEEP has less adverse hemodynamic consequences. has less adverse hemodynamic consequences.

Automatic control of tracheal tube cuff pressure in ventilated patients in semirecumbent position: a randomized trial.

PubMed

Valencia, Mauricio; Ferrer, Miquel; Farre, Ramon; Navajas, Daniel; Badia, Joan Ramon; Nicolas, Josep Maria; Torres, Antoni

2007-06-01

The aspiration of subglottic secretions colonized by bacteria pooled around the tracheal tube cuff due to inadvertent deflation (<20 cm H2O) of the cuff plays a relevant role in the pathogenesis of ventilator-associated pneumonia. We assessed the efficacy of an automatic, validated device for the continuous regulation of tracheal tube cuff pressure in preventing ventilator-associated pneumonia. Prospective randomized controlled trial. Respiratory intensive care unit and general medical intensive care unit. One hundred and forty-two mechanically ventilated patients (age, 64 +/- 17 yrs; Acute Physiology and Chronic Health Evaluation II score, 18 +/- 6) without pneumonia or aspiration at admission. Within 24 hrs of intubation, patients were randomly allocated to undergo continuous regulation of the cuff pressure with the automatic device (n = 73) or routine care of the cuff pressure (control group, n = 69). Patients remained in a semirecumbent position in bed. The primary end point variable was the incidence of ventilator-associated pneumonia. Main causes for intubation were decreased consciousness (43, 30%) and exacerbation of chronic respiratory diseases (38, 27%). Cuff pressure <20 cm H2O was more frequently observed in the control than the automatic group (45.3 vs. 0.7% determinations, p < .001). However, the rate of ventilator-associated pneumonia with clinical criteria (16, 22% vs. 20, 29%) and microbiological confirmation (11, 15% vs. 10, 15%), the distribution of early and late onset, the causative microorganisms, and intensive care unit (20, 27% vs. 16, 23%) and hospital mortality (30, 41% vs. 23, 33%) were similar for the automatic and control groups, respectively. Cuff pressure is better controlled with the automatic device. However, it did not result in additional benefits to the semirecumbent position in preventing ventilator-associated pneumonia.

The predictive value of external continuous lumbar drainage, with cerebrospinal fluid outflow controlled by medium pressure valve, in normal pressure hydrocephalus.

PubMed

Panagiotopoulos, V; Konstantinou, D; Kalogeropoulos, A; Maraziotis, T

2005-09-01

Although sporadic studies have described temporary external cerebrospinal fluid (CSF) lumbar drainage as a highly accurate test for predicting the outcome after ventricular shunting in normal pressure hydrocephalus (NPH) patients, a more recent study reports that the positive predictive value of external lumbar drainage (ELD) is high but the negative predictive value is deceptively low. Therefore, we conducted a prospective study in order to evaluate the predictive value of a continuous ELD, with CSF outflow controlled by medium pressure valve, in NPH patients. Twenty-seven patients with presumed NPH were admitted to our department and CSF drainage was carried out by a temporary (ELD) with CSF outflow controlled by a medium pressure valve for five days. All patients received a ventriculoperitoneal shunt using a medium pressure valve based upon preoperative clinical and radiographic criteria of NPH, regardless of ELD outcome. Clinical evaluation of gait disturbances, urinary incontinence and mental status, and radiological evaluation with brain CT was performed prior to and after ELD test, as well as three months after shunting. Twenty-two patients were finally shunted and included in this study. In a three-month follow-up, using a previously validated score system, overall improvement after permanent shunting correlated well to improvement after ELD test (Spearman's rho = 0.462, p = 0.03). When considering any degree of improvement as a positive response, ELD test yielded high positive predictive values for all individual parameters (gait disturbances 94%, 95% CI 71%-100%, urinary incontinence 100%, 95% CI 66%-100%, and mental status 100%, 95% CI 66%-100%) but negative predictive values were low (< 50%) except for cognitive impairment (85%, 95% CI 55%-98%). This study suggests that a positive ELD-valve system test should be considered a reliable criterion for preoperative selection of shunt-responsive NPH patients. In case of a negative ELD-valve system test, further investigation of the presumed NPH patients with additional tests should be performed.

Nasal versus oronasal continuous positive airway pressure masks for obstructive sleep apnea: a pilot investigation of pressure requirement, residual disease, and leak.

PubMed

Bakker, Jessie P; Neill, Alister M; Campbell, Angela J

2012-09-01

This single-blinded, randomized, controlled pilot study aimed to investigate whether there is a difference between nasal and oronasal masks in therapeutic continuous positive airway pressure (CPAP) requirement, residual disease, or leak when treating obstructive sleep apnea (OSA) and if differences were related to measures of upper airway size. Patients with severe OSA currently using CPAP at ≥4 h/night with a nasal mask were examined (including Mallampati scale, incisal relationship, and mandibular protrusion) and then randomized to receive auto-positive airway pressure (PAP) or fixed CPAP at a manually titrated pressure for 1 week each at home, with immediate crossover. Within each week, a nasal mask and two oronasal masks were to be used for two or three nights each in random order. Data were downloaded from the device. Twelve patients completed the trial (mean ± SD AHI 59.8 ± 28.6 events/h; CPAP 11.1 ± 3.2 cmH(2)O; BMI 37.7 ± 5.0 kg/m(2)). During auto-PAP, the median 95th percentile pressure delivered with all masks was within 0.5 cmH(2)O (p > 0.05). During CPAP, median residual AHI was 0.61 (IQR = 1.18) for the nasal mask, 1.70 (IQR = 4.04) for oronasal mask 1, and 2.48 (IQR = 3.74) for oronasal mask 2 (p = 0.03). The 95th percentile leak was lowest with the nasal mask during both CPAP and auto-PAP (both p < 0.01). Differences in pressure or residual disease were not related to measures of upper airway shape or body habitus. In obese OSA patients changing from a nasal to oronasal mask increased leak and residual AHI but did not affect the therapeutic pressure requirement. The findings of the current study highlight mask leak as the major difficulty in the use of oronasal masks.

A Randomized Crossover Trial Comparing Autotitrating and Continuous Positive Airway Pressure in Subjects With Symptoms of Aerophagia: Effects on Compliance and Subjective Symptoms.

PubMed

Shirlaw, Teresa; Hanssen, Kevin; Duce, Brett; Hukins, Craig

2017-07-15

To assess the benefit and tolerance of autotitrating positive airway pressure (APAP) versus continuous positive airway pressure (CPAP) in subjects who experience aerophagia. This is the report of a prospective, two-week, double-blinded, randomized crossover trial set in an Australian clinical sleep laboratory in a tertiary hospital. Fifty-six subjects who reported symptoms of aerophagia that they attributed to CPAP were recruited. Full face masks were used by 39 of the 56 subjects recruited. Subjects were randomly and blindly allocated to either CPAP at their treatment recommended pressure or APAP 6-20 cm H 2 O, in random order. Subjects spent two weeks on each therapy mode. Therapy usage hours, 95th centile pressure, maximum pressure, 95th centile leak, and residual apnea-hypopnea index (AHI) were reported at the end of each two-week treatment period. Functional Outcome of Sleepiness Questionnaire, Epworth Sleepiness Scale, and visual analog scale to measure symptoms of aerophagia were also completed at the end of each 2-week treatment arm. The median pressure ( P < .001) and 95th centile pressure ( P < .001) were reduced with APAP but no differences in compliance ( P = .120) and residual AHI were observed. APAP reduced the symptoms of bloating ( P = .011), worst episode of bloating ( P = .040), flatulence ( P = .010), and belching ( P = .001) compared to CPAP. There were no differences in Epworth Sleepiness Scale or Functional Outcome of Sleepiness Questionnaire outcomes between CPAP and APAP. APAP therapy reduces the symptoms of aerophagia while not affecting compliance when compared with CPAP therapy. Australian and New Zealand Clinical Trials Registry at https://www.anzctr.org.au, trial number ACTRN12611001250921. A commentary on this article appears in this issue on page 859. © 2017 American Academy of Sleep Medicine

Focus control system for stretched-membrane mirror module

DOEpatents

Butler, B.L.; Beninga, K.J.

1991-05-21

A focus control system dynamically sets and controls the focal length of a reflective membrane supported between a perimeter frame. A rear membrane is also supported between the perimeter frame rearward and spaced apart from a back side of the reflective membrane. The space between the membranes defines a plenum space into which a mass of gas at a first pressure is inserted. The pressure differential between the first pressure and an external pressure, such as the atmospheric pressure, causes the reflective membrane to assume a first curvature relative to a reference plane associated with the perimeter frame. This curvature defines the focal length of the reflective membrane. The focal length is dynamically controlled by changing the volume of the plenum space, thereby changing the first pressure. The system can be used to change or maintain the pressure differential and hence the front membrane curvature. The plenum volume is changed by pushing or pulling on a central section of the rear membrane using a suitable actuator. Sensing means continuously sense the location of the reflective membrane relative to the reference plane. This sensed position is compared to a reference position, and a resulting error signal, comprising the difference between the sensed position and reference position, drives the actuator in a direction to minimize the difference. A vent value compensates for temperature changes or leaks in the closed volume by allowing the pressure differential to be adjusted as required to center the working range of the actuator about the desired focal length. 13 figures.

Focus control system for stretched-membrane mirror module

DOEpatents

Butler, Barry L.; Beninga, Kelly J.

1991-01-01

A focus control system dynamically sets and controls the focal length of a reflective membrane supported between a perimeter frame. A rear membrane is also supported between the perimeter frame rearward and spaced apart from a back side of the reflective membrane. The space between the membranes defines a plenum space into which a mass of gas at a first pressure is inserted. The pressure differential between the first pressure and an external pressure, such as the atmospheric pressure, causes the reflective membrane to assume a first curvature relative to a reference plane associated with the perimeter frame. This curvature defines the focal length of the reflective membrane. The focal length is dynamically controlled by changing the volume of the plenum space, thereby changing the first pressure. The system can be used to change or maintain the pressure differential and hence the front membrane curvature. The plenum volume is changed by pushing or pulling on a central section of the rear membrane using a suitable actuator. Sensing means continuously sense the location of the reflective membrane relative to the reference plane. This sensed position is compared to a reference position, and a resulting error signal, comprising the difference between the sensed position and reference position, drives the actuator in a direction to minimize the difference. A vent value compensates for temperature changes or leaks in the closed volume by allowing the pressure differential to be adjusted as required to center the working range of the actuator about the desired focal length.

A randomized controlled trial of post-extubation bubble continuous positive airway pressure versus Infant Flow Driver continuous positive airway pressure in preterm infants with respiratory distress syndrome.

PubMed

Gupta, Samir; Sinha, Sunil K; Tin, Win; Donn, Steven M

2009-05-01

To compare the efficacy and safety of bubble continuous positive airway pressure (CPAP) and Infant Flow Driver (IFD) CPAP for the post-extubation management of preterm infants with respiratory distress syndrome (RDS). A total of 140 preterm infants at 24 to 29 weeks' gestation or with a birth weight of 600 to 1500 g who were ventilated at birth for RDS were randomized to receive either IFD CPAP (a variable-flow device) or bubble CPAP (a continuous-flow device). A standardized protocol was used for extubation and CPAP. No crossover was allowed. The primary outcome was successful extubation maintained for at least 72 hours. Secondary outcomes included successful extubation maintained for 7 days, total duration of CPAP support, chronic lung disease, and complications of prematurity. Seventy-one infants were randomized to bubble CPAP, and 69 were randomized to IFD CPAP. Mean gestational age and birth weight were similar in the 2 groups, as were the proportions of infants who achieved successful extubation for 72 hours and for 7 days. However, the median duration of CPAP support was 50% shorter in the infants on bubble CPAP. Moreover, in the subset of infants who were ventilated for less than 14 days, the infants on bubble CPAP had a significantly lower extubation failure rate. There was no difference in the incidence of chronic lung disease or other complications between the 2 study groups. Bubble CPAP is as effective as IFD CPAP in the post-extubation management of infants with RDS; however, in infants ventilated for < or = 14 days, bubble CPAP is associated with a significantly higher rate of successful extubation. Bubble CPAP also is associated with a significantly reduced duration of CPAP support.

Application of a barometer for assessment of oral functions: Donders space.

PubMed

Hiraki, K; Yamada, Y; Kurose, M; Ofusa, W; Sugiyama, T; Ishida, R

2017-01-01

We developed a barometer applicable to a small space, to assess oral and pharyngeal functions. Negative oral pressure during rest and pressure changes during swallowing were measured in a space between the palate and tongue (STP). Twenty volunteers were asked to sit in a chair in a relaxed upright position. A sensor was placed on the posterior midline of hard palate. Recording commenced just before subjects closed their lips and continued. Subjects were asked to swallow saliva and keep the apposition. Finally, subjects were asked to open their mouth. Recordings were performed five times, and 5 s of continuous data in each phase was averaged. To verify the reliability of the system, the same procedure was accomplished with twin sensors. When the jaw and lips were closed, the pressure slightly decreased from atmospheric pressure (-0·17 ± 0·24-kPa). After swallowing, the pressure in STP showed more negative value (-0·50 ± 0·59-kPa). There is a significant difference between the values in open condition and after swallowing (P < 0·001) and between values after swallowing and final open condition (P < 0·05). Twin sensor showed almost the same trajectories of pressure changes for all the recordings. Obtained negative pressure might generate about 0·71-N of force and would be enough to keep the tongue in the palatal fossa at rest. The system detected large negative/positive pressure changes during swallowing. We conclude this system may be a tool to evaluate oral functions. © 2016 John Wiley & Sons Ltd.

WE-G-BRF-09: Force- and Image-Adaptive Strategies for Robotised Placement of 4D Ultrasound Probes

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

Kuhlemann, I; Graduate School for Computing in Life Science, University of Luebeck, Luebeck; Bruder, R

2014-06-15

Purpose: To allow continuous acquisition of high quality 4D ultrasound images for non-invasive live tracking of tumours for IGRT, image- and force-adaptive strategies for robotised placement of 4D ultrasound probes are developed and evaluated. Methods: The developed robotised ultrasound system is based on a 6-axes industrial robot (adept Viper s850) carrying a 4D ultrasound transducer with a mounted force-torque sensor. The force-adaptive placement strategies include probe position control using artificial potential fields and contact pressure regulation by a PD controller strategy. The basis for live target tracking is a continuous minimum contact pressure to ensure good image quality and highmore » patient comfort. This contact pressure can be significantly disturbed by respiratory movements and has to be compensated. All measurements were performed on human subjects under realistic conditions. When performing cardiac ultrasound, rib- and lung shadows are a common source of interference and can disrupt the tracking. To ensure continuous tracking, these artefacts had to be detected to automatically realign the probe. The detection is realised by multiple algorithms based on entropy calculations as well as a determination of the image quality. Results: Through active contact pressure regulation it was possible to reduce the variance of the contact pressure by 89.79% despite respiratory motion of the chest. The results regarding the image processing clearly demonstrate the feasibility to detect image artefacts like rib shadows in real-time. Conclusion: In all cases, it was possible to stabilise the image quality by active contact pressure control and automatically detected image artefacts. This fact enables the possibility to compensate for such interferences by realigning the probe and thus continuously optimising the ultrasound images. This is a huge step towards fully automated transducer positioning and opens the possibility for stable target tracking in ultrasoundguided radiation therapy requiring contact pressure of 5–10 N. This work was supported by the Graduate School for Computing in Medicine and Life Sciences funded by Germany's Excellence Initiative [DFG GSC 235/1].« less

Evaluation of an active seating system for pressure relief.

PubMed

Koo, T K; Mak, A F; Lee, Y L

1995-01-01

In the first part of this study, the inflation-pressure and interface-pressure profiles of an active cushion system, the Talley active air bellows cushion, were examined continuously for one complete working cycle using the dynamic pressure monitor. The relationship between the inflation pressure and the interface pressure was explored. A well-defined relationship was found in the areas directly over the air bellows. In the second part of this study, the pressure-relieving characteristics of the active cushion were assessed quantitatively and compared to two types of passive cushions--the Roho high-profile air floatation cushion and the polyurethane (PU) foam cushion. Eight non-disabled subjects were positioned on the active cushion at two inflation-pressure levels--30 mmHg and 60 mmHg, or on the Roho or the PU foam cushions. Interface pressures were recorded using the Oxford pressure monitor. For the active cushion it was shown that the higher the inflation pressure was, the better the pressure-relieving characteristics seemed to be. In general, the pressure-relieving characteristics of the active cushion were not as good as those of the passive cushions being tested. The active cushion could alter the pressures over the ischial tuberosities cyclically but the amount of pressure alternation depended on the relative position of the ischial tuberosities and the air bellows.

Positive emotion inducement modulates cardiovascular responses caused by mental work.

PubMed

Liu, Xinxin; Ishimatsu, Kazuma; Sotoyama, Midori; Iwakiri, Kazuyuki

2016-11-16

Positive emotion is considered as an important factor related to health-relevant biological processes, including cardiovascular responses. To explore the possibility of using positive emotion as a tool to manage cardiovascular response of white-collar workers, we examined the influence on cardiovascular response of positive emotion inducement before a mental work. Seventeen healthy males participated and performed a 10-min, PC-based Stroop color word task as their mental work. Before the task, 60 pleasant pictures chosen from the International Affective Picture System were presented in a random order under a positive emotion inducement condition while a gray screen was presented under a control condition. A 30-min relaxation period after completing the task was provided to examine the aftereffects of positive emotion inducement. Throughout these periods, systolic and diastolic blood pressure, mean arterial blood pressure, heart rate, stroke volume, cardiac output, and total peripheral resistance were measured continuously. Blood pressure and total peripheral resistance were lower during the picture presentation period under the positive emotion inducement period compared to the control condition. All indices did not differ during the color word task period. During the relaxation period after the task, however, blood pressure and total peripheral resistance were lower under the positive emotion inducement condition compared to the control condition. Positive emotion inducement before a mental work beneficially modulates cardiovascular responses, suggesting that positive emotion inducement may be a useful tool to manage the cardiovascular response to mental work.

Pressure mapping to assess seated pressure distributions and the potential risk for skin ulceration in a population of sledge hockey players and control subjects.

PubMed

Berthold, Justin; Dicianno, Brad E; Cooper, Rory A

2013-09-01

Ice sledge (or sled) hockey is a fast-paced sport that enables individuals with physical disabilities to play ice hockey. As the attraction to the sport continues to rise, the need for developing better equipment and installing preventative measures for injury will become increasingly important. One such injury includes skin pressure ulceration. A total of 26 subjects including active controls and those with spinal cord injury, multiple sclerosis, limb amputation and traumatic brain injury were studied using a pressure mapping device at the 2012 National Disabled Veterans Winter Sports Clinic to determine the risk for skin pressure ulceration and the impact of cushioning and knee angle positioning on seated pressure distributions. Sledge hockey athletes may be at increased risk for skin pressure ulceration based on seated pressure distribution data. This experiment failed to demonstrate a benefit for specialty cushioning in either group. Interestingly, knee angle positioning, particularly, knee extension significantly lowered the average seated pressures. When considering the risk for skin pressure ulceration, knee angle positioning is of particular clinical importance. More research is warranted, specifically targeting novel cushion and sledge designs and larger groups of individuals with sensory loss and severe spinal deformities. Implications for Rehabilitation Ice sledge (or sled) hockey is a fast-paced and growing adaptive sport played at the Paralympic level. Rehabilitation professionals should consider the potential for skin ulceration in this population of athletes. The effects of cushioning used in the sledge design warrants further investigation. Knee angle positioning; particularly, knee extension significantly lowers seated pressures and may reduce the potential for skin ulceration.

Choosing an Oronasal Mask to Deliver Continuous Positive Airway Pressure May Cause More Upper Airway Obstruction or Lead to Higher Continuous Positive Airway Pressure Requirements than a Nasal Mask in Some Patients: A Case Series.

PubMed

Ng, Justin R; Aiyappan, Vinod; Mercer, Jeremy; Catcheside, Peter G; Chai-Coetzer, Ching Li; McEvoy, R Doug; Antic, Nick

2016-09-15

The choice of mask interface used with continuous positive airway pressure (CPAP) therapy can affect the control of upper airway obstruction (UAO) in obstructive sleep apnea (OSA). We describe a case series of four patients with paradoxical worsening of UAO with an oronasal mask and the effect of changing to a nasal mask. We retrospectively reviewed the case histories of 4 patients and recorded patient demographics, in-laboratory and ambulatory CPAP titration data, CPAP therapy data, type of mask interface used and potential confounding factors. The 4 cases (mean ± SD: age = 59 ± 16 y; BMI = 30.5 ± 4.5 kg/m(2)) had a high residual apnoea-hypopnea index (AHI) (43 ± 14.2 events/h) and high CPAP pressure requirements (14.9 ± 6.6 cmH2O) with an oronasal mask. Changing to a nasal mask allowed adequate control of UAO with a significant reduction in the average residual AHI (3.1 ± 1.5 events/h). In two of the four cases, it was demonstrated that control of UAO was obtained at a much lower CPAP pressure compared to the oronasal mask (Case one = 17.5 cmH2O vs 12cmH2O; Case two = 17.9 cmH2O vs 7.8 cmH2O). Other potential confounding factors were unchanged. There are various physiological observations that may explain these findings but it is uncertain which individuals are susceptible to these mechanisms. If patients have OSA incompletely controlled by CPAP with evidence of residual UAO and/or are requiring surprisingly high CPAP pressure to control OSA with an oronasal mask, the choice of mask should be reviewed and consideration be given to a trial of a nasal mask. A commentary on this article appears in this issue on page 1209. © 2016 American Academy of Sleep Medicine.

Increased dead space in face mask continuous positive airway pressure in neonates.

PubMed

Hishikawa, Kenji; Fujinaga, Hideshi; Ito, Yushi

2017-01-01

Continuous positive airway pressure (CPAP) by face mask is commonly performed in newborn resuscitation. We evaluated the effect of face mask CPAP on system dead space. Face mask CPAP increases dead space. A CPAP model study. We estimated the volume of the inner space of the mask. We devised a face mask CPAP model, in which the outlet of the mask was covered with plastic; and three modified face mask CPAP models, in which holes were drilled near to the cushion of the covered face mask to alter the air exit. We passed a continuous flow of 21% oxygen through each model and we controlled the inner pressure to 5 cmH 2 O by adjusting the flow-relief valve. To evaluate the ventilation in the inner space of each model, we measured the oxygen concentration rise time, that is, the time needed for the oxygen concentration of each model to reach 35% after the oxygen concentration of the continuous flow was raised from 21% to 40%. The volume of inner space of the face mask was 38.3 ml. Oxygen concentration rise time in the face mask CPAP model was significantly longer at various continuous flow rates and points of the inner space of the face mask compared with that of the modified face mask CPAP model. Our study indicates that face mask CPAP leads to an increase in dead space and a decrease in ventilation efficiency under certain circumstances. Pediatr Pulmonol. 2017;52:107-111. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Method for continuous control of composition and doping of pulsed laser deposited films by pressure control

DOEpatents

Lowndes, Douglas H.; McCamy, James W.

1996-01-01

A method for growing a deposit upon a substrate of semiconductor material involves the utilization of pulsed laser deposition techniques within a low-pressure gas environment. The substrate and a target of a first material are positioned within a deposition chamber and a low-pressure gas atmosphere is developed within the chamber. The substrate is then heated, and the target is irradiated, so that atoms of the target material are ablated from the remainder of the target, while atoms of the gas simultaneously are adsorbed on the substrate/film surface. The ablated atoms build up upon the substrate, together with the adsorbed gas atoms to form the thin-film deposit on the substrate. By controlling the pressure of the gas of the chamber atmosphere, the composition of the formed deposit can be controlled, and films of continuously variable composition or doping can be grown from a single target of fixed composition.

Infant Flow Driver or single prong nasal continuous positive airway pressure: short-term physiological effects.

PubMed

Ahluwalia, J S; White, D K; Morley, C J

1998-03-01

The effectiveness of single prong nasal continuous positive airway pressure (CPAP) was compared with the Infant Flow Driver (IFD) in a crossover study in 20 neonates treated with > or = 30% oxygen by nasal CPAP. They were randomized to the device used at the start of the study. Each infant was studied for four consecutive 2-h periods alternating between single prong nasal CPAP and the IFD. The FiO2 from the IFD read 0.02 higher than the same setting on the ventilators used for single prong nasal CPAP. The IFD improved the mean (95% CI) of the FiO2 by 0.05 (0.02-0.08), p = 0.008. Taking into account the systematic error in the FiO2 between the devices the real mean improvement in FiO2 produced by the IFD was 0.03 (-0.005 to 0.06), p=0.09. There were no significant differences in respiratory rate, heart rate, blood pressure or comfort score of infants during periods of single nasal prong CPAP compared with periods on the IFD.

Sustained Inflation and Its Role in the Delivery Room Management of Preterm Infants.

PubMed

Lista, Gianluca; La Verde, Paola Azzurra; Castoldi, Francesca

2016-01-01

A noninvasive approach in the delivery room in place of intubation and mechanical ventilation can reduce rates of bronchopulmonary dysplasia and death. Nevertheless, the rate of nasal continuous positive airway pressure failure still remains high. In order to prevent lung injury and to enhance the success of continuous positive airway pressure, sustained inflation (administration by face mask or nasopharyngeal tube of a high peak pressure of 20-25 cm H2O, maintained for 10-15 s) has been recently proposed to establish an early and efficient functional residual capacity in the delivery room. Sustained inflation is an intriguing therapy, although the results of clinical trials are controversial in terms of respiratory outcomes. A critical role in the success of sustained inflation could be the presence of open or closed glottis and the contribution of spontaneous breathing that allows air to enter the lungs during the maneuver. Recent neonatal resuscitation guidelines suggest that sustained inflation may be considered in individual clinical circumstances or research settings. © 2016 S. Karger AG, Basel.

Continuous chain bit with downhole cycling capability

DOEpatents

Ritter, Don F.; St. Clair, Jack A.; Togami, Henry K.

1983-01-01

A continuous chain bit for hard rock drilling is capable of downhole cycling. A drill head assembly moves axially relative to a support body while the chain on the head assembly is held in position so that the bodily movement of the chain cycles the chain to present new composite links for drilling. A pair of spring fingers on opposite sides of the chain hold the chain against movement. The chain is held in tension by a spring-biased tensioning bar. A head at the working end of the chain supports the working links. The chain is centered by a reversing pawl and piston actuated by the pressure of the drilling mud. Detent pins lock the head assembly with respect to the support body and are also operated by the drilling mud pressure. A restricted nozzle with a divergent outlet sprays drilling mud into the cavity to remove debris. Indication of the centered position of the chain is provided by noting a low pressure reading indicating proper alignment of drilling mud slots on the links with the corresponding feed branches.

[Anesthetic management for cerebral aneurysm surgery in a patient with aortitis syndrome accompanied by lung edema].

PubMed

Maeda, Ryoko; Kohno, Yumiko; Hoshino, Hajime; Suzuki, Hideo; Hirabayashi, Yoshiyuki; Seo, Norimasa

2003-08-01

A 48-year-old woman with aortitis syndrome underwent clipping of dissecting aneurysm of the left posterior inferior cerebellar artery following subarachnoid hemorrhage. Preoperative echocardiography demonstrated moderate aortic regurgitation and pulmonary hypertension. Intravenous infusion (1900 ml.day-1) was performed to avoid cerebral vasospasm, but the patient developed lung edema. She received delayed surgical treatment after the improvement of lung symptoms. Anesthesia was induced with fentanyl (0.1 mg), propofol (90 mg) and vecuronium (6 mg). Radial arterial flow was judged to be insufficient for cannulation, and a cannulation was therefore performed on the dorsal pedis artery. During induction of anesthesia, there was a significant decrease in the arterial pressure, that required a total of 32 mg of intravenous ephedrine. Following tracheal intubation, a central venous catheter was inserted and dopamine was continuously administered. The patient was positioned in the park bench position. We thought that the placement of the introducer for Swan-Ganz catheter was difficult under the position and Swan-Ganz catheter was not inserted. Anesthesia was maintained with sevoflurane, air, and oxygen. We continuously monitored the central venous pressure as an indicator of fluid balance. In this case, we monitored dorsal pedis arterial pressure directly, which might not be sufficiently reliable to predict the decrease in cerebral blood flow.

The effect of continuous positive airway pressure on middle ear pressure.

PubMed

Sivri, Bekir; Sezen, Ozan Seymen; Akbulut, Sevtap; Coskuner, Temel

2013-05-01

To investigate the effect of continuous positive airway pressure (CPAP) on middle ear pressure in patients with obstructive sleep apnea syndrome (OSAS). Prospective clinical case-control study. Seventy-eight patients with moderate and severe OSAS (the mean apnea-hypopnea indexes were 22.70 ± 3.59 and 48.59 ± 12.50, respectively) using CPAP (study group) and 60 patients with no sleep apnea syndrome (control group) were included in the study. Forty-two of the patients were female and 96 were male. The mean age in the study group was 47.38 ± 6.23, whereas it was 46.10 ± 11.96 in the control group (P > .05). The middle ear pressure of all study subjects was evaluated with tympanometry at the beginning of the study and 6 months later. Tympanometric measurements of both groups were compared. Furthermore, the same data for the study group were also evaluated according to CPAP pressure levels. The middle ear peak pressure values of the patients in the study group were significantly increased from -63.04 ± 55.82 daPa to -39.6 ± 27.72 daPa after 6 months (P < .01). The middle ear pressure in the control group was found to be -13.26 ± 22.60 daPa at the beginning of the study and -13.60 ± 38.82 daPa after 6 months (P > .05). The mean middle ear pressure level was significantly higher in patients using CPAP at 12 to 14 cm H2 O pressure than in those using CPAP at 8 to 10 cm H2 O pressure (P < .05). There was a significant increase in the middle ear pressure of patients using CPAP regularly for 6 months. This increase was proportional to the pressure level of the CPAP device. 3b. Copyright © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

The Learning Intention of Low-Qualified Employees: A Key for Participation in Lifelong Learning and Continuous Training

ERIC Educational Resources Information Center

Kyndt, Eva; Govaerts, Natalie; Dochy, Filip; Baert, Herman

2011-01-01

In our continuously changing society, a need for updating one's skills and knowledge puts pressure on safeguarding the labour market position of low-qualified employees. However, prior research and official statistics show that employees with a lower level of education tend to participate less in training than highly-educated individuals. This…

Bubble Continuous Positive Airway Pressure Enhances Lung Volume and Gas Exchange in Preterm Lambs

PubMed Central

Pillow, J. Jane; Hillman, Noah; Moss, Timothy J. M.; Polglase, Graeme; Bold, Geoff; Beaumont, Chris; Ikegami, Machiko; Jobe, Alan H.

2007-01-01

Rationale: The technique used to provide continuous positive airway pressure (CPAP) to the newborn may influence lung function and breathing efficiency. Objectives: To compare differences in gas exchange physiology and lung injury resulting from treatment of respiratory distress with either bubble or constant pressure CPAP and to determine if the applied flow influences short-term outcomes. Methods: Lambs (133 d gestation; term is 150 d) born via cesarean section were weighed, intubated, and treated with CPAP for 3 hours. Two groups were treated with 8 L/minute applied flow using the bubble (n = 12) or the constant pressure (n = 12) technique. A third group (n = 10) received the bubble method with 12 L/minute bias flow. Measurements at study completion included arterial blood gases, oxygraphy, capnography, tidal flow, multiple breath washout, lung mechanics, static pressure–volume curves, and bronchoalveolar lavage fluid protein. Measurements and Main Results: Birth weight and arterial gas variables at 15 minutes were comparable. Flow (8 or 12 L/min) did not influence the 3-hour outcomes in the bubble group. Bubble technique was associated with a higher pH, PaO2, oxygen uptake, and area under the flow–volume curve, and a decreased alveolar protein, respiratory quotient, PaCO2, and ventilation inhomogeneity compared with the constant pressure group. Conclusions: Compared with constant pressure technique, bubble CPAP promotes enhanced airway patency during treatment of acute postnatal respiratory disease in preterm lambs and may offer protection against lung injury. PMID:17431223

Influence of body position on the displacement of nasal prongs in preterm newborns receiving continuous positive airway pressure

PubMed Central

Brunherotti, Marisa Afonso Andrade; Martinez, Francisco Eulógio

2015-01-01

Abstract Objective: To evaluate the influence of body position on the displacement of nasal prongs in preterm infants. Methods: This prospective, randomized, crossover study enrolled infants born at a mean gestational age of 29.7±2 weeks, birth weight of 1353±280g and 2.9±2.2 days of life, submitted to continuous positive airway pressure by nasal prongs. The main outcome was the number of times that the nasal prongs were displaced following infant positioning in the following body positions: prone, right lateral, left lateral, and supine, according to a pre-established random order. Moreover, cardiorespiratory variables (respiratory rate, heart rate, and oxygen saturation) were evaluated for each body position. Data for each position were collected every 10 min, over a period of 60 min. An occurrence was defined when the nasal prongs were displaced from the nostrils after 3 min in the desired position, requiring intervention of the examiner. Results: Among the 16 studied infants, the occurrence of nasal prong displacement was only observed in the prone position (9 infants - 56.2%) and in the left lateral position (2 infants - 12.5%). The number of times that the prongs were displaced was 11 in the prone position (7 within the first 10min) and 2 in the left lateral position (1 within the first 10min). No clinically significant changes were observed in the cardiorespiratory variables. Conclusions: Maintenance of the nasal prongs to provide adequate noninvasive respiratory support was harder in the prone position. PMID:26116326

Development and Implementation of a Training-of-Trainers Program for Continuous Positive Airway Pressure in Neonatal and Pediatric Patients in Five Low- and Middle-Income Countries.

PubMed

Wilson, Patrick T; Benckert, Megan M; Moresky, Rachel T; Morris, Marilyn C

2017-10-01

We describe a pragmatic training-of-trainers program for the use of continuous positive airway pressure (CPAP) for neonatal and pediatric patients. The program is designed for medical professionals working in low- and middle-income countries and involves 2 days of in-class training followed by 1 day of in-service training. The program was created after training in Cambodia, Ghana, Honduras, Kenya and Rwanda and addresses the issues of resource availability, cultural context and local buy-in and partnership in low- and middle-income countries. We hope others will use the training program to increase knowledge and use of CPAP with the ultimate goal of improving neonatal and pediatric survival globally. © The Author [2017]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Left ventricular ejection fraction in obstructive sleep apnea. Effects of long-term treatment with nasal continuous positive airway pressure.

PubMed

Krieger, J; Grucker, D; Sforza, E; Chambron, J; Kurtz, D

1991-10-01

The effects of treatment with nasal continuous positive airway pressure (CPAP) on left ventricular ejection fraction (LVEF) were assessed in 29 patients with obstructive sleep apnea (OSA) in a prospective study using multiple gated equilibrium radionuclide angiocardiography. All patients were evaluated before CPAP treatment was initiated and were reevaluated after one year (mean +/- SE, 415 +/- 6 days), of home treatment with nasal CPAP. The mean LVEF increased from 59 +/- 1 percent to 63 +/- 1 percent (p less than 0.005). The degree of improvement in LVEF was correlated with baseline LVEF (r = 0.54; p less than 0.003), meaning that the lower the baseline value, the greater the increase with treatment. The changes were not different when subgroups of medicated and unmedicated patients were considered separately. These results show that long-term nasal CPAP treatment results in improved left ventricular function in OSA.

Continuous positive airway pressure for the treatment of obstructive sleep apnea.

PubMed

Nurwidya, Fariz; Susanto, Agus Dwi; Juzar, Dafsah A; Kobayashi, Isao; Yunus, Faisal

2016-01-01

Obstructive sleep apnea (OSA) is a recurrent episode of partial or complete upper airway obstruction during sleep despite ongoing respiratory efforts and is implicated as the risk factor of cardiovascular disease. The OSA syndrome is typified by recurring partial or total occlusion of the pharynx, sleep fragmentation, episodes of gasping, and, eventually, daytime sleepiness. If it is left untreated, OSA syndrome can cause hypertension, coronary artery disease congestive heart disease, insulin resistance and death. In this review, we describe the pathogenesis and diagnosis of OSA. We also focused on the continuous positive airway pressure (CPAP) as the main therapy for OSA. CPAP has been shown to provide benefit for not only respiratory system, but also for cardiovascular system and metabolic system. Finally, we discussed briefly about the issue of adherence of using CPAP that could contribute to lower compliant in patient with OSA.

Continuous positive airway pressure (CPAP) to treat respiratory distress in newborns in low- and middle-income countries.

PubMed

Dewez, Juan Emmanuel; van den Broek, Nynke

2017-01-01

Severe respiratory distress is a serious complication common to the three major causes of neonatal mortality and morbidity (prematurity, intra-partum-related hypoxia and infections). In low- and middle-income countries (LMICs), 20% of babies presenting with severe respiratory distress die.Continuous positive airway pressure (CPAP), is an effective intervention for respiratory distress in newborns and widely used in high-income countries. Following the development of simple, safe and relatively inexpensive CPAP devices, there is potential for large-scale implementation in the developing world.In this article, we describe existing CPAP systems and present a review of the current literature examining the effectiveness of CPAP compared to standard care (oxygen) in newborns with respiratory distress. We also discuss the evidence gap which needs to be addressed prior to its integration into health systems in LMICs. © The Author(s) 2016.

Continuous positive airway pressure (CPAP) to treat respiratory distress in newborns in low- and middle-income countries

PubMed Central

van den Broek, Nynke

2016-01-01

Severe respiratory distress is a serious complication common to the three major causes of neonatal mortality and morbidity (prematurity, intra-partum-related hypoxia and infections). In low- and middle-income countries (LMICs), 20% of babies presenting with severe respiratory distress die. Continuous positive airway pressure (CPAP), is an effective intervention for respiratory distress in newborns and widely used in high-income countries. Following the development of simple, safe and relatively inexpensive CPAP devices, there is potential for large-scale implementation in the developing world. In this article, we describe existing CPAP systems and present a review of the current literature examining the effectiveness of CPAP compared to standard care (oxygen) in newborns with respiratory distress. We also discuss the evidence gap which needs to be addressed prior to its integration into health systems in LMICs. PMID:26864235

Continuous pressure letdown system

DOEpatents

Sprouse, Kenneth M.; Matthews, David R.; Langowski, Terry

2010-06-08

A continuous pressure letdown system connected to a hopper decreases a pressure of a 2-phase (gas and solid) dusty gas stream flowing through the system. The system includes a discharge line for receiving the dusty gas from the hopper, a valve, a cascade nozzle assembly positioned downstream of the discharge line, a purge ring, an inert gas supply connected to the purge ring, an inert gas throttle, and a filter. The valve connects the hopper to the discharge line and controls introduction of the dusty gas stream into the discharge line. The purge ring is connected between the discharge line and the cascade nozzle assembly. The inert gas throttle controls a flow rate of an inert gas into the cascade nozzle assembly. The filter is connected downstream of the cascade nozzle assembly.

Incentive spirometry for preventing pulmonary complications after coronary artery bypass graft.

PubMed

Freitas, Eliane R F S; Soares, Bernardo G O; Cardoso, Jefferson R; Atallah, Álvaro N

2012-09-12

Incentive spirometry (IS) is a treatment technique that uses a mechanical device to reduce pulmonary complications during postoperative care. This is an update of a Cochrane review first published in 2007. Update the previously published systematic review to compare the effects of IS for preventing postoperative pulmonary complications in adults undergoing coronary artery bypass graft (CABG). We searched CENTRAL and DARE on The Cochrane Library (Issue 2 of 4 2011), MEDLINE OVID (1948 to May 2011), EMBASE (1980 to Week 20 2011), LILACS (1982 to July 2011) , the Physiotherapy Evidence Database (PEDro) (1980 to July 2011), Allied & Complementary Medicine (AMED) (1985 to May 2011), CINAHL (1982 to May 2011). Randomised controlled trials comparing IS with any type of prophylactic physiotherapy for prevention of postoperative pulmonary complications in adults undergoing CABG. Two reviewers independently evaluated trial quality using the guidelines of the Cochrane Handbook for Systematic Reviews and extracted data from included trials. For continuous outcomes, we used the generic inverse variance method for meta-analysis and for dichotomous data we used the Peto Odds Ratio. This update included 592 participants from seven studies (two new and one that had been excluded in the previous review in 2007. There was no evidence of a difference between groups in the incidence of any pulmonary complications and functional capacity between treatment with IS and treatment with physical therapy, positive pressure breathing techniques (including continuous positive airway pressure (CPAP), bilevel positive airway pressure (BiPAP) and intermittent positive pressure breathing (IPPB), active cycle of breathing techniques (ACBT) or preoperative patient education. Patients treated with IS had worse pulmonary function and arterial oxygenation compared with positive pressure breathing. Based on these studies there was no improvement in the muscle strength between groups who received IS demonstrated by maximal inspiratory pressure and maximal expiratory pressure . Our update review suggests there is no evidence of benefit from IS in reducing pulmonary complications and in decreasing the negative effects on pulmonary function in patients undergoing CABG. In view of the modest number of patients studied, methodological shortcomings and poor reporting of the included trials, these results should still be interpreted cautiously. An appropriately powered trial of high methodological rigour is needed to determine if there are patients who may derive benefit from IS following CABG.

Rate of rise in diastolic blood pressure influences vascular sympathetic response to mental stress.

PubMed

El Sayed, Khadigeh; Macefield, Vaughan G; Hissen, Sarah L; Joyner, Michael J; Taylor, Chloe E

2016-12-15

Research indicates that individuals may experience a rise (positive responders) or fall (negative responders) in muscle sympathetic nerve activity (MSNA) during mental stress. In this study, we examined the early blood pressure responses (including the peak, time of peak and rate of rise in blood pressure) to mental stress in positive and negative responders. Negative MSNA responders to mental stress exhibit a more rapid rise in diastolic pressure at the onset of the stressor, suggesting a baroreflex-mediated suppression of MSNA. In positive responders there is a more sluggish rise in blood pressure during mental stress, which appears to be MSNA-driven. This study suggests that whether MSNA has a role in the pressor response is dependent upon the reactivity of blood pressure early in the task. Research indicates that individuals may experience a rise (positive responders) or fall (negative responders) in muscle sympathetic nerve activity (MSNA) during mental stress. The aim was to examine the early blood pressure response to stress in positive and negative responders and thus its influence on the direction of change in MSNA. Blood pressure and MSNA were recorded continuously in 21 healthy young males during 2 min mental stressors (mental arithmetic, Stroop test) and physical stressors (cold pressor, handgrip exercise, post-exercise ischaemia). Participants were classified as negative or positive responders according to the direction of the mean change in MSNA during the stressor tasks. The peak changes, time of peak and rate of changes in blood pressure were compared between groups. During mental arithmetic negative responders experienced a significantly greater rate of rise in diastolic blood pressure in the first minute of the task (1.3 ± 0.5 mmHg s -1 ) compared with positive responders (0.4 ± 0.1 mmHg s -1 ; P = 0.03). Similar results were found for the Stroop test. Physical tasks elicited robust parallel increases in blood pressure and MSNA across participants. It is concluded that negative MSNA responders to mental stress exhibit a more rapid rise in diastolic pressure at the onset of the stressor, suggesting a baroreflex-mediated suppression of MSNA. In positive responders there is a more sluggish rise in blood pressure during mental stress, which appears to be MSNA-driven. This study suggests that whether MSNA has a role in the pressor response is dependent upon the reactivity of blood pressure early in the task. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Rate of rise in diastolic blood pressure influences vascular sympathetic response to mental stress

PubMed Central

El Sayed, Khadigeh; Macefield, Vaughan G.; Hissen, Sarah L.; Joyner, Michael J.

2016-01-01

Key points Research indicates that individuals may experience a rise (positive responders) or fall (negative responders) in muscle sympathetic nerve activity (MSNA) during mental stress.In this study, we examined the early blood pressure responses (including the peak, time of peak and rate of rise in blood pressure) to mental stress in positive and negative responders.Negative MSNA responders to mental stress exhibit a more rapid rise in diastolic pressure at the onset of the stressor, suggesting a baroreflex‐mediated suppression of MSNA. In positive responders there is a more sluggish rise in blood pressure during mental stress, which appears to be MSNA‐driven.This study suggests that whether MSNA has a role in the pressor response is dependent upon the reactivity of blood pressure early in the task. Abstract Research indicates that individuals may experience a rise (positive responders) or fall (negative responders) in muscle sympathetic nerve activity (MSNA) during mental stress. The aim was to examine the early blood pressure response to stress in positive and negative responders and thus its influence on the direction of change in MSNA. Blood pressure and MSNA were recorded continuously in 21 healthy young males during 2 min mental stressors (mental arithmetic, Stroop test) and physical stressors (cold pressor, handgrip exercise, post‐exercise ischaemia). Participants were classified as negative or positive responders according to the direction of the mean change in MSNA during the stressor tasks. The peak changes, time of peak and rate of changes in blood pressure were compared between groups. During mental arithmetic negative responders experienced a significantly greater rate of rise in diastolic blood pressure in the first minute of the task (1.3 ± 0.5 mmHg s−1) compared with positive responders (0.4 ± 0.1 mmHg s−1; P = 0.03). Similar results were found for the Stroop test. Physical tasks elicited robust parallel increases in blood pressure and MSNA across participants. It is concluded that negative MSNA responders to mental stress exhibit a more rapid rise in diastolic pressure at the onset of the stressor, suggesting a baroreflex‐mediated suppression of MSNA. In positive responders there is a more sluggish rise in blood pressure during mental stress, which appears to be MSNA‐driven. This study suggests that whether MSNA has a role in the pressor response is dependent upon the reactivity of blood pressure early in the task. PMID:27690366

Effect on lung function of continuous positive airway pressure administered either by infant flow driver or a single nasal prong.

PubMed

Kavvadia, V; Greenough, A; Dimitriou, G

2000-04-01

The aim of this study was to assess if continuous positive airways pressure (CPAP) delivered by an infant flow driver (IFD) was a more effective method of improving lung function than delivering CPAP by a single nasal prong. A total of 36 infants (median gestational age 29 weeks, range 25-35 weeks) were studied, 12 who received CPAP via an IFD, 12 who received CPAP via a single nasal prong and 12 without CPAP. CPAP was administered post extubation if apnoeas and bradycardias or a respiratory acidosis developed or electively if the infant was of birth weight <1.0 kg. Lung function was assessed by the supplementary oxygen requirement and measurement of compliance of the respiratory system using an occlusion technique. Assessments were made immediately prior to and after 24 h of CPAP administration and at similar postnatal ages in the non-CPAP group. The infants who did not require CPAP had better lung function (non significant) than the other two groups before they received CPAP. After 24 h, lung function had improved in both CPAP groups to the level of the non CPAP infants. The supplementary oxygen requirements of all three groups decreased over the 24 h period, but this only reached significance in the single nasal prong group (P<0.05). Four infants supported by the IFD, but none with a single nasal prong, became hyperoxic. Continuous positive airways pressure administration via the infant flow driver appears to offer no short-term advantage over a single nasal prong system when used after extubation in preterm infants.

Circulating FABP4 and FABP5 levels are differently linked to OSA severity and treatment.

PubMed

Català, Raquel; Cabré, Anna; Hernández-Flix, Salvador; Ferré, Raimón; Sangenís, Sandra; Plana, Núria; Texidó, Anna; Masana, Lluís

2013-12-01

To evaluate circulating adipocyte and epidermal fatty acid-binding protein (FABP4 and FABP5) concentrations in patients with obstructive sleep apnea (OSA), as well as the effects of continuous positive airway pressure (CPAP) treatment. Our cross-sectional study included 125 patients. After polysomnography, 58 participants met the criteria for CPAP treatment and were included in a closed cohort study of 8 weeks of CPAP treatment. General anthropometric and biochemical data and circulating FABP4 and FABP5 levels were determined in all patients at baseline and after CPAP treatment in those receiving this therapy. Circulating FABP4 but not FABP5 levels were higher in patients with OSA (P = 0.003). FABP4 but not FABP5 values were associated with parameters of OSA severity independently of age, gender, adiposity and insulin resistance (P < 0.05). FABP4 but not FABP5 concentrations were determinants of OSA presence (OR: 1.11, P = 0.010) and severity (OR: 1.06, P = 0.020). After CPAP treatment, FABP4 levels decreased in the more severe patients (P = 0.019), while FABP5 levels increased in all patients (P < 0.001). FABP4 is directly associated with obstructive sleep apnea severity and did not change with continuous positive airway pressure treatment, while FABP5 was not associated with obstructive sleep apnea severity and increased with continuous positive airway pressure treatment. FABP4 and FABP5 have different associations with obstructive sleep apnea. FABP4 but not FABP5 could be considered a marker of metabolic alterations in obstructive sleep apnea patients.

[Sleep apnea syndrome as a cause of secondary hypertension. A case report].

PubMed

Poreba, Rafał; Derkacz, Arkadiusz; Andrzejak, Ryszard

2005-11-01

A case of a 51-year old man, suffering from drug-resistant hypertension, complaining of hypersomnia and fatigue during the day, is presented. In the course of diagnostic procedures the diagnosis of sleep apnea syndrome was established. Continuous positive airway pressure (CPAP) therapy was successfully started. Examination carried out 3 months later revealed good response to pharmacological treatment with normal levels of blood pressure.

40 CFR 60.5200 - How do I develop a site-specific monitoring plan for my continuous monitoring, bag leak detection...

Code of Federal Regulations, 2011 CFR

2011-07-01

... the flow sensor and other necessary equipment in a position that provides a representative flow. (2) Use a flow sensor with a measurement sensitivity of no greater than 2 percent of the expected process... sensor(s) in a position that provides a representative measurement of the pressure (e.g., particulate...

Orotracheal tube as a risk factor for lower respiratory tract infection: preliminary data from a randomised trial.

PubMed

Muzlovic, Igor; Perme, Janja; Stubljar, David

2018-05-01

The aim of the study was to investigate whether polyurethane (PU) endotracheal tubes, continuous measurements of cuff pressure and aspiration of the subglottic space as a bundle of parameters could reduce patients' risk for developing ventilator associated pneumonia (VAP). Two groups of patients that differed only in terms of endotracheal tubes and intubation intervention were compared. Group A was ventilated using PU tubes a with conical cuff; they also had continuous cuff pressure measurement and continuous subglottic aspiration. Group B was ventilated using PVC tubes with a cylindrical cuff; the patients underwent intermittent cuff pressure measurement and intermittent subglottic aspiration. Seven patients in group A (13.2%) and 18 in group B (36.0%) out of 103 were diagnosed with VAP. VAP patients were in general older, stayed longer in the ICU and were ventilated significantly longer compared with the patients with no VAP. Eight more patients in group B died compared with group A. Moreover, subjects in group A survived longer. Patient age, hours on mechanical ventilation, and days on an ICU were all positively associated with the occurrence of VAP. Prevention parameters in ventilation (PU cuff, conical cuff, continuous subglottic drainage and continuous cuff pressure measurement) could prevent the incidence of VAP in ICU patients.

The OPTIMIST-A trial: evaluation of minimally-invasive surfactant therapy in preterm infants 25–28 weeks gestation

PubMed Central

2014-01-01

Background It is now recognized that preterm infants ≤28 weeks gestation can be effectively supported from the outset with nasal continuous positive airway pressure. However, this form of respiratory therapy may fail to adequately support those infants with significant surfactant deficiency, with the result that intubation and delayed surfactant therapy are then required. Infants following this path are known to have a higher risk of adverse outcomes, including death, bronchopulmonary dysplasia and other morbidities. In an effort to circumvent this problem, techniques of minimally-invasive surfactant therapy have been developed, in which exogenous surfactant is administered to a spontaneously breathing infant who can then remain on continuous positive airway pressure. A method of surfactant delivery using a semi-rigid surfactant instillation catheter briefly passed into the trachea (the “Hobart method”) has been shown to be feasible and potentially effective, and now requires evaluation in a randomised controlled trial. Methods/design This is a multicentre, randomised, masked, controlled trial in preterm infants 25–28 weeks gestation. Infants are eligible if managed on continuous positive airway pressure without prior intubation, and requiring FiO2 ≥ 0.30 at an age ≤6 hours. Randomisation will be to receive exogenous surfactant (200 mg/kg poractant alfa) via the Hobart method, or sham treatment. Infants in both groups will thereafter remain on continuous positive airway pressure unless intubation criteria are reached (FiO2 ≥ 0.45, unremitting apnoea or persistent acidosis). Primary outcome is the composite of death or physiological bronchopulmonary dysplasia, with secondary outcomes including incidence of death; major neonatal morbidities; durations of all modes of respiratory support and hospitalisation; safety of the Hobart method; and outcome at 2 years. A total of 606 infants will be enrolled. The trial will be conducted in >30 centres worldwide, and is expected to be completed by end-2017. Discussion Minimally-invasive surfactant therapy has the potential to ease the burden of respiratory morbidity in preterm infants. The trial will provide definitive evidence on the effectiveness of this approach in the care of preterm infants born at 25–28 weeks gestation. Trial registration Australia and New Zealand Clinical Trial Registry: ACTRN12611000916943; ClinicalTrials.gov: NCT02140580. PMID:25164872

Oscillation-Mark Formation and Liquid-Slag Consumption in Continuous Casting Mold

NASA Astrophysics Data System (ADS)

Yang, Jie; Meng, Xiangning; Wang, Ning; Zhu, Miaoyong

2017-04-01

Traditional understanding on the complex multiphysics phenomenon of the meniscus in the oscillating mold for continuously cast steel, including oscillation-mark formation and liquid-slag consumption, has never considered the shape influence of the flux channel between the mold wall and the solidifying shell surface. Based on the reciprocating oscillation of mold, this study was carried out to calculate theoretically the periodic pressure and the liquid-slag layer thickness in the flux channel for the upper and the lower meniscus that possess different shapes in combination with a transient equilibrium profile of the flux channel as well as the sinusoidal and the nonsinusoidal oscillation modes of mold. The effect of flux channel shape on the multiphysics phenomenon in the meniscus was determined by the physical oscillation simulation by using an experimental cold model mold. The results show that the shape difference between the upper and the lower meniscus leads to the opposite direction of pressure in the flux channel. The pressure in the opposite direction plays a respective role in oscillation-mark formation and liquid-slag consumption in an oscillation cycle of mold, and thus, it makes a new mechanism for explaining the multiphysics phenomenon in the meniscus. The oscillation mark is initially formed by the rapid increase of positive channel pressure in the upper meniscus, and most of the liquid slag is infiltrated into the flux channel by the negative channel pressure in the lower meniscus from the end of a positive strip time to the beginning of the next positive strip time, including the negative strip time in between. Furthermore, the physical characteristics of the lubrication behavior in the meniscus are summarized, including liquid-slag infiltration, solidifying shell deformation, and the thickness change of the liquid-slag layer.

High ratio recirculating gas compressor

DOEpatents

Weinbrecht, J.F.

1989-08-22

A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor. 10 figs.

Hyperbaric pressure effects measured by growth of a transplantable tumor in the C3H/HeN mouse.

PubMed

Herndon, B L; Lally, J J

1984-09-01

Both hypobaric exposure at 0.5 atmospheres absolute (ATA) and hyperbaric pressure exposure at 3.5-8 ATA slowed transplantable tumor growth. These experiments detailed the hyperbaric pressure exposure. C3H/HeN-MTV+ mice, bearing the 16/C transplantable murine mammary adenocarcinoma and exposed to 18 days' treatment by a hyperbaric chamber at 3.5-8 ATA, had tumor weights that averaged 50-75% less than the tumor weights in mice caged at ambient ("sea level") pressure. A series of experiments was run to investigate this response to hyperbaric pressure exposure. After mice underwent continuous exposure to 3.5-8 ATA normoxic (normal oxygen) hyperbaric pressure with use of either argon or nitrogen inert gas, which began 3 days after tumor inoculation, tumors were removed at about 3 weeks' growth from these pressure-exposed mice and measured for growth by weighing. Final tumor weight in pressure-exposed experimental mice was significantly less than tumor weight in paired groups of tumor-bearing controls that received no hyperbaric pressure. Tumor weight was inversely related to pressure "dose," although the small pressure range produced an effect at all pressures used. The number of compression-decompression cycles to which the animals were subjected, however, was related positively to tumor weight at necropsy. Continued tumor growth in mice subjected to frequent pressure change (in conjunction with pressure exposure that otherwise limited tumor size) was unexplained by these experiments. The greatest difference between tumor weights in controls and pressure-exposed animals was seen with 2 weeks' continuous pressure exposure. A limited profile of blood tests was performed, and these reflected only minor, expected change in the pressure-exposed experimental animals. The data at hand did not suggest a mechanism by which chronic normoxic hyperbaric pressure limited tumor size.

Investigation of the relationship between neutrophil-to-lymphocyte ratio and obstructive sleep apnoea syndrome.

PubMed

Yenigun, A; Karamanli, H

2015-09-01

To investigate the neutrophil-to-lymphocyte ratio and sleep apnoea severity relationship. Patients (n = 178) were assigned to five groups according to apnoea-hypopnea indices and continuous positive airway pressure use. White blood cell, neutrophil, lymphocyte and neutrophil-to-lymphocyte ratio values were compared for each group. The neutrophil-to-lymphocyte ratio values of severe obstructive sleep apnoea syndrome patients (group 4) were significantly higher than those of: control patients (group 1), mild obstructive sleep apnoea syndrome patients (group 2) and patients treated with continuous positive airway pressure (group 5) (p = 0.008, p = 0.008 and p = 0.003). Minimum oxygen saturation values of group 4 were significantly lower than those of groups 1, 2 and 5 (p = 0.0005, p = 0.011 and p = 0.001). There was a positive correlation between apnoea-hypopnea index and neutrophil-to-lymphocyte ratio (r = 0.758, p = 0.034), and a negative correlation between apnoea-hypopnea index and minimum oxygen saturation (r = -0.179, p = 0.012). Neutrophil-to-lymphocyte ratio may be used to determine disease severity, complementing polysomnography.

Atmospheric pressure loading effects on Global Positioning System coordinate determinations

NASA Technical Reports Server (NTRS)

Vandam, Tonie M.; Blewitt, Geoffrey; Heflin, Michael B.

1994-01-01

Earth deformation signals caused by atmospheric pressure loading are detected in vertical position estimates at Global Positioning System (GPS) stations. Surface displacements due to changes in atmospheric pressure account for up to 24% of the total variance in the GPS height estimates. The detected loading signals are larger at higher latitudes where pressure variations are greatest; the largest effect is observed at Fairbanks, Alaska (latitude 65 deg), with a signal root mean square (RMS) of 5 mm. Out of 19 continuously operating GPS sites (with a mean of 281 daily solutions per site), 18 show a positive correlation between the GPS vertical estimates and the modeled loading displacements. Accounting for loading reduces the variance of the vertical station positions on 12 of the 19 sites investigated. Removing the modeled pressure loading from GPS determinations of baseline length for baselines longer than 6000 km reduces the variance on 73 of the 117 baselines investigated. The slight increase in variance for some of the sites and baselines is consistent with expected statistical fluctuations. The results from most stations are consistent with approximately 65% of the modeled pressure load being found in the GPS vertical position measurements. Removing an annual signal from both the measured heights and the modeled load time series leaves this value unchanged. The source of the remaining discrepancy between the modeled and observed loading signal may be the result of (1) anisotropic effects in the Earth's loading response, (2) errors in GPS estimates of tropospheric delay, (3) errors in the surface pressure data, or (4) annual signals in the time series of loading and station heights. In addition, we find that using site dependent coefficients, determined by fitting local pressure to the modeled radial displacements, reduces the variance of the measured station heights as well as or better than using the global convolution sum.

Negative-Pressure Hydrocephalus: A Case Report on Successful Treatment Under Intracranial Pressure Monitoring with Bilateral Ventriculoperitoneal Shunts.

PubMed

Pandey, Sajan; Jin, Yi; Gao, Liang; Zhou, Cheng Cheng; Cui, Da Ming

2017-03-01

Negative-pressure hydrocephalus (NegPH), a very rare condition of unknown etiology and optimal treatment, usually presents postneurosurgery with clinical and imaging features of hydrocephalus, but with negative cerebrospinal fluid pressure. We describe a NegPH case of -3 mm Hg intracranial pressure that was successfully treated to achieve 5 mm Hg under continuous intracranial pressure monitoring with horizontal positioning, head down and legs elevated to 10°-15°, neck wrapping for controlled venous drainage, chest and abdomen bandages, infusion of 5% dextrose fluid to lower plasma osmolarity (Na + , 130-135 mmol/L), daily cerebrospinal fluid drainage >200 mL, and arterial blood gas partial pressure of carbon dioxide >40 mm Hg. Copyright © 2016 Elsevier Inc. All rights reserved.

Aerosol delivery and humidification with the Boussignac continuous positive airway pressure device.

PubMed

Thille, Arnaud W; Bertholon, Jean-François; Becquemin, Marie-Hélène; Roy, Monique; Lyazidi, Aissam; Lellouche, François; Pertusini, Esther; Boussignac, Georges; Maître, Bernard; Brochard, Laurent

2011-10-01

A simple method for effective bronchodilator aerosol delivery while administering continuing continuous positive airway pressure (CPAP) would be useful in patients with severe bronchial obstruction. To assess the effectiveness of bronchodilator aerosol delivery during CPAP generated by the Boussignac CPAP system and its optimal humidification system. First we assessed the relationship between flow and pressure generated in the mask with the Boussignac CPAP system. Next we measured the inspired-gas humidity during CPAP, with several humidification strategies, in 9 healthy volunteers. We then measured the bronchodilator aerosol particle size during CPAP, with and without heat-and-moisture exchanger, in a bench study. Finally, in 7 patients with acute respiratory failure and airway obstruction, we measured work of breathing and gas exchange after a β(2)-agonist bronchodilator aerosol (terbutaline) delivered during CPAP or via standard nebulization. Optimal humidity was obtained only with the heat-and-moisture exchanger or heated humidifier. The heat-and-moisture exchanger had no influence on bronchodilator aerosol particle size. Work of breathing decreased similarly after bronchodilator via either standard nebulization or CPAP, but P(aO(2)) increased significantly only after CPAP aerosol delivery. CPAP bronchodilator delivery decreases the work of breathing as effectively as does standard nebulization, but produces a greater oxygenation improvement in patients with airway obstruction. To optimize airway humidification, a heat-and-moisture exchanger could be used with the Boussignac CPAP system, without modifying aerosol delivery.

[Comparison of different continuous positive airway pressure titration methods for obstructive sleep apnea hypopnea syndrome].

PubMed

Li, Jingjing; Ye, Jingying; Zhang, Peng; Kang, Dan; Cao, Xin; Zhang, Yuhuan; Ding, Xiu; Zheng, Li; Li, Hongguang; Bian, Qiuli

2014-10-01

To explore whether there were differences between the results of automatic titration and the results of manual titration for positive airway pressure treatment in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and its influencing factors, the results might provide a theoretical basis for the rational use of two pressure titration methods. Sixty one patients with OSAHS were included in this study. All patients underwent a manual titration and an automatic titration within one week. The clinical informations, polysomnography data, and the results of both two titration of all patients were obtained for analysis. The overall apnea/hypopnea index was (63.1 ± 17.7)/h, with a range of 14.9/h to 110.4/h. The treatment pressure of manual titration was (8.4 ± 2.1) cmH(2)O, which was significantly lower than the treatment pressure of automatic titration, (11.5 ± 2.7) cmH(2)O (t = -9.797, P < 0.001). After using a ΔP of 3 cmH(2)O for the cutoff value (ΔP was defined as the difference of automatic titration and manual titration), it was found that the pressure of automatic titration was significantly higher in patients with a ΔP > 3 cmH(2)O than in patients with a ΔP ≤ 3 cmH(2)O, which was (13.3 ± 2.3) cmH(2)O vs (10.0 ± 2.0) cmH(2)O (t = -6.159, P < 0.001). However, there were no differences for the pressure of manual titration between these two groups, which was (8.6 ± 2.4) cmH(2)O vs (8.3 ± 2.0)cmH(2)O (P > 0.05). There was no significant difference in age, body mass index, neck circumference, abdomen circumference, apnea hypopnea index, and arterial oxygen saturation between these two groups. The treatment pressure of automatic titration is usually higher than that of manual titration. For patients with a high treatment pressure which is derived from automatic titration, a suggestion about manual titration could be given to decrease the potential treatment pressure of continuous positive airway pressure, which may be helpful in improving the comfortableness and the compliance of this treatment.

21 CFR 211.48 - Plumbing.

Code of Federal Regulations, 2012 CFR

2012-04-01

... CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS Buildings and Facilities § 211.48 Plumbing. (a) Potable water shall be supplied under continuous positive pressure in a plumbing system free of defects that could contribute contamination to any drug product. Potable water shall meet the...

21 CFR 211.48 - Plumbing.

Code of Federal Regulations, 2014 CFR

2014-04-01

... CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS Buildings and Facilities § 211.48 Plumbing. (a) Potable water shall be supplied under continuous positive pressure in a plumbing system free of defects that could contribute contamination to any drug product. Potable water shall meet the...

21 CFR 211.48 - Plumbing.

Code of Federal Regulations, 2013 CFR

2013-04-01

... CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS Buildings and Facilities § 211.48 Plumbing. (a) Potable water shall be supplied under continuous positive pressure in a plumbing system free of defects that could contribute contamination to any drug product. Potable water shall meet the...

21 CFR 211.48 - Plumbing.

Code of Federal Regulations, 2011 CFR

2011-04-01

... CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS Buildings and Facilities § 211.48 Plumbing. (a) Potable water shall be supplied under continuous positive pressure in a plumbing system free of defects that could contribute contamination to any drug product. Potable water shall meet the...

Dissociative Identity Disorder CPAP Adherence: An Uncommon Factor in Obstructive Sleep Apnea.

PubMed

Gandotra, Kamal; Golish, Joseph; Rosenberg, Carl; Strohl, Kingman

2018-04-15

We present a case of a patient with dissociative identity disorder and symptomatic sleep apnea who was treated with continuous positive airway pressure (CPAP). CPAP use depended upon which personality the patient exhibited but apnea reduction did not. This case illustrates in one individual how personality can positively or negatively affect CPAP adherence. © 2018 American Academy of Sleep Medicine.

Effects of continuous visual feedback during sitting balance training in chronic stroke survivors.

PubMed

Pellegrino, Laura; Giannoni, Psiche; Marinelli, Lucio; Casadio, Maura

2017-10-16

Postural control deficits are common in stroke survivors and often the rehabilitation programs include balance training based on visual feedback to improve the control of body position or of the voluntary shift of body weight in space. In the present work, a group of chronic stroke survivors, while sitting on a force plate, exercised the ability to control their Center of Pressure with a training based on continuous visual feedback. The goal of this study was to test if and to what extent chronic stroke survivors were able to learn the task and transfer the learned ability to a condition without visual feedback and to directions and displacement amplitudes different from those experienced during training. Eleven chronic stroke survivors (5 Male - 6 Female, age: 59.72 ± 12.84 years) participated in this study. Subjects were seated on a stool positioned on top of a custom-built force platform. Their Center of Pressure positions were mapped to the coordinate of a cursor on a computer monitor. During training, the cursor position was always displayed and the subjects were to reach targets by shifting their Center of Pressure by moving their trunk. Pre and post-training subjects were required to reach without visual feedback of the cursor the training targets as well as other targets positioned in different directions and displacement amplitudes. During training, most stroke survivors were able to perform the required task and to improve their performance in terms of duration, smoothness, and movement extent, although not in terms of movement direction. However, when we removed the visual feedback, most of them had no improvement with respect to their pre-training performance. This study suggests that postural training based exclusively on continuous visual feedback can provide limited benefits for stroke survivors, if administered alone. However, the positive gains observed during training justify the integration of this technology-based protocol in a well-structured and personalized physiotherapy training, where the combination of the two approaches may lead to functional recovery.

Type of mask may impact on continuous positive airway pressure adherence in apneic patients.

PubMed

Borel, Jean Christian; Tamisier, Renaud; Dias-Domingos, Sonia; Sapene, Marc; Martin, Francis; Stach, Bruno; Grillet, Yves; Muir, Jean François; Levy, Patrick; Series, Frederic; Pepin, Jean-Louis

2013-01-01

In obstructive sleep apnea patients (OSA), continuous positive airway pressure (CPAP) adherence is crucial to improve symptoms and cardiometabolic outcomes. The choice of mask may influence CPAP adherence but this issue has never been addressed properly. To evaluate the impact of nasal pillows, nasal and oronasal masks on CPAP adherence in a cohort of OSA. Newly CPAP treated OSA participating in "Observatoire Sommeil de la Fédération de Pneumologie", a French national prospective cohort, were included between March 2009 and December 2011. Anthropometric data, medical history, OSA severity, sleepiness, depressive status, treatment modalities (auto-CPAP versus fixed pressure, pressure level, interface type, use of humidifiers) and CPAP-related side effects were included in multivariate analysis to determine independent variables associated with CPAP adherence. 2311 OSA (age = 57(12) years, apnea+hypopnea index = 41(21)/h, 29% female) were included. Nasal masks, oronasal masks and nasal pillows were used by 62.4, 26.2 and 11.4% of the patients, respectively. In univariate analysis, oronasal masks and nasal pillows were associated with higher risk of CPAP non-adherence. CPAP non-adherence was also associated with younger age, female gender, mild OSA, gastroesophageal reflux, depression status, low effective pressure and CPAP-related side effects. In multivariate analysis, CPAP non-adherence was associated with the use of oronasal masks (OR = 2.0; 95%CI = 1.6; 2.5), depression, low effective pressure, and side effects. As oronasal masks negatively impact on CPAP adherence, a nasal mask should be preferred as the first option. Patients on oronasal masks should be carefully followed.

Symptoms of aerophagia are common in patients on continuous positive airway pressure therapy and are related to the presence of nighttime gastroesophageal reflux.

PubMed

Shepherd, Kelly; Hillman, David; Eastwood, Peter

2013-01-15

Continuous positive airway pressure (CPAP), the mainstay treatment for obstructive sleep apnea (OSA), involves administration of air under pressure to the upper airway. A well-known but poorly understood side effect of positive airway pressure therapies is aerophagia, air entering the esophagus and stomach rather than the lungs. Gastric distension, a consequence of aerophagia, can increase gastroesophageal reflux (GER) by increasing transient lower esophageal sphincter relaxations, the most common cause of reflux. This study aimed to determine: (i) the prevalence of aerophagia symptoms in a group of OSA patients on CPAP therapy, and (ii) whether aerophagia symptoms are related to an increase in prevalence of GER symptoms. Consecutive OSA patients undergoing polysomnography for the purpose of optimizing their CPAP therapy completed a validated questionnaire regarding GER symptoms and aerophagia symptoms. Complete datasets were collected for 259 individuals (203 males). The group with aerophagia symptoms (n = 130) had a greater prevalence of frequent (≥ once a week) GER symptoms (29% vs. 10%, p < 0.05) and nighttime GER symptoms (9 vs. 2%, p < 0.05) than those without aerophagia (n = 129). The group with nighttime GER symptoms (n = 27) had a greater prevalence of aerophagia symptoms (63% vs. 23%, p < 0.05) than those without nighttime GER symptoms (n = 232). In patients with OSA being treated with CPAP, the prevalence of GER and nighttime GER symptoms is greater in those with symptoms of aerophagia than those without. CPAP-induced aerophagia might precipitate GER, particularly nighttime GER, by exacerbating transient lower esophageal relaxations through gastric distension.

High-precision GPS autonomous platforms for sea ice dynamics and physical oceanography

NASA Astrophysics Data System (ADS)

Elosegui, P.; Wilkinson, J.; Olsson, M.; Rodwell, S.; James, A.; Hagan, B.; Hwang, B.; Forsberg, R.; Gerdes, R.; Johannessen, J.; Wadhams, P.; Nettles, M.; Padman, L.

2012-12-01

Project "Arctic Ocean sea ice and ocean circulation using satellite methods" (SATICE), is the first high-rate, high-precision, continuous GPS positioning experiment on sea ice in the Arctic Ocean. The SATICE systems collect continuous, dual-frequency carrier-phase GPS data while drifting on sea ice. Additional geophysical measurements also collected include ocean water pressure, ocean surface salinity, atmospheric pressure, snow-depth, air-ice-ocean temperature profiles, photographic imagery, and others, enabling sea ice drift, freeboard, weather, ice mass balance, and sea-level height determination. Relatively large volumes of data from each buoy are streamed over a satellite link to a central computer on the Internet in near real time, where they are processed to estimate the time-varying buoy positions. SATICE system obtains continuous GPS data at sub-minute intervals with a positioning precision of a few centimetres in all three dimensions. Although monitoring of sea ice motions goes back to the early days of satellite observations, these autonomous platforms bring out a level of spatio-temporal detail that has never been seen before, especially in the vertical axis. These high-resolution data allows us to address new polar science questions and challenge our present understanding of both sea ice dynamics and Arctic oceanography. We will describe the technology behind this new autonomous platform, which could also be adapted to other applications that require high resolution positioning information with sustained operations and observations in the polar marine environment, and present results pertaining to sea ice dynamics and physical oceanography.

Bi-level positive airway pressure (BiPAP) and acute cardiogenic pulmonary oedema (ACPO) in the emergency department.

PubMed

Murray, Sarah

2002-05-01

Patients in acute respiratory failure (ARF) frequently present to the emergency department (ED). Traditionally management has involved mechanical ventilation via endotracheal intubation. Such invasive forms of treatment, however, correlate with a higher incidence of infection, mortality, length of stay and contribute to the costs of intensive care. Non-invasive positive pressure ventilation (NIPPV) such as bi-level positive airway pressure (BiPAP) may therefore provide an alternative and preferable form of treatment. Whilst contemporary literature supports the use of BiPAP in hypercapnic ARF, its role in acute hypoxaemic presentations remains elusive. Specifically, the efficacy and safety of BiPAP in the treatment of acute cardiogenic pulmonary oedema (ACPO) remains a contentious issue. The aim of this paper is to explore the physiological rationale for treatment of ACPO with BiPAP. Particular attention will focus on the comparative theoretical advantages of BiPAP in relation to continuous positive airway pressure (CPAP), and a review of recent research. Discussion will incorporate timeliness in the application of BiPAP, indicators of successful treatment, appropriate manipulation of pressure settings, nursing workload and management of patients beyond the ED. Whilst the theoretical advantages of BiPAP ventilation are acknowledged, larger randomised controlled research studies are recommended in order to clearly ensure its safe and effective application in the treatment of ACPO.

The burden of the 'RA RA' positive: survivors' and hospice patients' reflections on maintaining a positive attitude to serious illness.

PubMed

McGrath, Pam

2004-01-01

This article seeks to make a contribution to fostering work on the neglected area of research about how individuals maintain a positive outlook during their confrontation with serious illness. Insights are presented from both haematology survivors and hospice patients about the factors that hinder and facilitate their capacity to 'be positive'. Open-ended interviews with 14 hospice patients and 12 haematology survivors on their construction of meaning in the face of serious illness were audio-recorded, transcribed verbatim and thematically analysed. The findings on the topic of maintaining a positive outlook are presented in this article. Although the participants affirmed the value of a positive perspective on their illness experience, they were critical of unwanted pressure from others to be positive: a phenomenon they called the 'RA RA' positive. Such pressure interfered with the natural process of continually having to re-negotiate a positive outlook through exploring the fullness of feeling, both positive and negative. The participants indicated that at times of relapse or worsening physical condition they had to cycle through a process of despair/negativity and re-adjustment before they were able to find the positive. The process could not be rushed and required freedom from an imposed pressure to be positive. The essential message is that a positive outlook cannot be imposed but requires a nurturing orientation that allows the expression of a full range of feelings in a supportive environment.

The effect of positive and negative message framing on short term continuous positive airway pressure compliance in patients with obstructive sleep apnea

PubMed Central

Czaban, Marcin; Berry, Marc P.; Nirmalan, Prajeshan; Brown, Richard; Birdseye, Adam; Woroszyl, Asia; Chapman, Julia; Kent, Brian D.; Hart, Nicholas; Rossi, Gian Paolo; Steier, Joerg

2018-01-01

Background Continuous positive airway pressure (CPAP), the best available treatment for obstructive sleep apnea (OSA), requires long-term compliance to be effective. Behavioral interventions may be used to improve adherence to CPAP. We aimed to investigate whether positive or negative message framing impacts on CPAP compliance in patients with OSA, when compared to standard care. Methods Consenting patients with confirmed OSA were randomly allocated to receive along with their CPAP either positively or negatively framed messages (Pos; Neg), or standard care (Con). Standardized motivational messages were read out to patients during an initial teaching session and through weekly telephone calls. Patients’ compliance data were reviewed 2 and 6 weeks following CPAP initiation. Results We randomized 112 patients to groups that were matched for age, BMI, and OSA severity. The positively framed group (Pos) showed greater CPAP usage after 2 weeks (total use 53.7±31.4 hours) as compared to the negatively framed and the control group (35.6±27.4 and 40.8±33.5 hours, P<0.05); however, no differences were seen at 6 weeks. There were more dropouts in the control group than in either framed groups (Pos n=5; Neg n=8; Con n=11; P<0.05). Conclusions Positively framed messages can improve CPAP adherence in patients with OSA in the short-term; however, strategies for implementing its long-term use need to be developed. PMID:29445540

The effect of positive and negative message framing on short term continuous positive airway pressure compliance in patients with obstructive sleep apnea.

PubMed

Pengo, Martino F; Czaban, Marcin; Berry, Marc P; Nirmalan, Prajeshan; Brown, Richard; Birdseye, Adam; Woroszyl, Asia; Chapman, Julia; Kent, Brian D; Hart, Nicholas; Rossi, Gian Paolo; Steier, Joerg

2018-01-01

Continuous positive airway pressure (CPAP), the best available treatment for obstructive sleep apnea (OSA), requires long-term compliance to be effective. Behavioral interventions may be used to improve adherence to CPAP. We aimed to investigate whether positive or negative message framing impacts on CPAP compliance in patients with OSA, when compared to standard care. Consenting patients with confirmed OSA were randomly allocated to receive along with their CPAP either positively or negatively framed messages (Pos; Neg), or standard care (Con). Standardized motivational messages were read out to patients during an initial teaching session and through weekly telephone calls. Patients' compliance data were reviewed 2 and 6 weeks following CPAP initiation. We randomized 112 patients to groups that were matched for age, BMI, and OSA severity. The positively framed group (Pos) showed greater CPAP usage after 2 weeks (total use 53.7±31.4 hours) as compared to the negatively framed and the control group (35.6±27.4 and 40.8±33.5 hours, P<0.05); however, no differences were seen at 6 weeks. There were more dropouts in the control group than in either framed groups (Pos n=5; Neg n=8; Con n=11; P<0.05). Positively framed messages can improve CPAP adherence in patients with OSA in the short-term; however, strategies for implementing its long-term use need to be developed.

A Case of Concomitant Obstructive Sleep Apnea and Non-Alcoholic Steatohepatitis Treated With CPAP Therapy

PubMed Central

Bajantri, Bharat; Lvovsky, Dmitry

2018-01-01

Obstructive sleep apnea syndrome is a disorder of sleep breathing that is a result of recurrent and intermittent hypoxia during sleep induced by the repeated partial or complete collapse of the upper airway, eventually causing chronic intermittent hypoxia. Non-alcoholic fatty liver disease is divided into non-alcoholic fatty liver and non-alcoholic steatohepatitis. Animal and human studies showed that obesity is associated with chronic liver hypoxia, even in the presence of systemic normoxia causing inflammation and release of cytokines. A “two-hit” model has been proposed. The first hit is characterized by insulin resistance and excess hepatic lipid accumulation secondary to abnormal fatty acid metabolism. Oxidative stress and inflammation are thought to comprise the second hit. Gold standard for the diagnosis of non-alcoholic steatohepatitis is a liver biopsy. Many clinical scores and non-invasive tools are used for the diagnosis of non-alcoholic steatohepatitis. Conservative management with lifestyle modifications including diet, exercise and weight loss remains the therapy of choice today. We present a case report of a 39-year-old man who was diagnosed with concomitant non-alcoholic steatohepatitis and severe obstructive sleep apnea. He was started treatment with continuous positive airway pressure and demonstrated excellent adherence to therapy for 6 years, with concomitant obstructive sleep apnea and non-alcoholic steatohepatitis which reversed with prolonged optimal continuous positive airway pressure therapy. Physical examination remained unremarkable except for morbid obesity. His abdominal girth, as well as body mass index, remained unchanged. After 6 years of optimal continuous positive airway pressure therapy, liver enzymes and relevant lipid panel normalized, suggesting reversal of non-alcoholic steatohepatitis. PMID:29915639

Efficacy of Bilevel-auto Treatment in Patients with Obstructive Sleep Apnea Not Responsive to or Intolerant of Continuous Positive Airway Pressure Ventilation

PubMed Central

Carlucci, Annalisa; Ceriana, Piero; Mancini, Marco; Cirio, Serena; Pierucci, Paola; D'Artavilla Lupo, Nadia; Gadaleta, Felice; Morrone, Elisa; Fanfulla, Francesco

2015-01-01

Background: Ventilation with continuous positive airway pressure (CPAP) is the gold standard therapy for obstructive sleep apnea (OSA). However, it was recently suggested that a novel mode of ventilation, Bilevel-auto, could be equally effective in treating patients unable to tolerate CPAP. The aim of this study was to investigate the ability of Bilevel-auto to treat OSA patients whose nocturnal ventilatory disturbances are not completely corrected by CPAP. Methods: We enrolled 66 consecutive OSA patients, not responsive to (group A) or intolerant of (group B) CPAP treatment, after a full night of manual CPAP titration in a laboratory. Full polysomnography data and daytime sleepiness score were compared for each group in the three different conditions: basal, during CPAP, and during Bilevel-auto. Results: The apnea-hypopnea index decreased significantly during CPAP in both groups; however, in the group A, there was a further significant improvement during Bilevel-auto. The same trend was observed for oxygenation indices, while the distribution and the efficiency of sleep did not differ following the switch from CPAP to Bilevel-auto. Conclusions: This study confirmed the role of Bilevel-auto as an effective therapeutic alternative to CPAP in patients intolerant of this latter mode of ventilation. Moreover, extending the use of Bilevel-auto to those OSA patients not responsive to CPAP, we showed a significantly better correction of nocturnal respiratory disturbances. Citation: Carlucci A, Ceriana P, Mancini M, Cirio S, Pierucci P, D'Artavilla Lupo N, Gadaleta F, Morrone E, Fanfulla F. Efficacy of Bilevel-auto treatment in patients with obstructive sleep apnea not responsive to or intolerant of continuous positive airway pressure ventilation. J Clin Sleep Med 2015;11(9):981–985. PMID:25902825

Treatment of Sleep Disordered Breathing Reverses Low Fetal Activity Levels in Preeclampsia

PubMed Central

Blyton, Diane M.; Skilton, Michael R.; Edwards, Natalie; Hennessy, Annemarie; Celermajer, David S.; Sullivan, Colin E.

2013-01-01

Study Objectives: Preeclampsia affects 5% to 7% of pregnancies, is strongly associated with low birth weight and fetal death, and is accompanied by sleep disordered breathing. We hypothesized that sleep disordered breathing may link preeclampsia with reduced fetal movements (a marker of fetal health), and that treatment of sleep disordered breathing might improve fetal activity during sleep. Design, Setting, and Participants: First, a method of fetal movement recording was validated against ultrasound in 20 normal third trimester pregnancies. Second, fetal movement was measured overnight with concurrent polysomnography in 20 patients with preeclampsia and 20 control subjects during third trimester. Third, simultaneous polysomnography and fetal monitoring was done in 10 additional patients with preeclampsia during a control night and during a night of nasal CPAP. Intervention: Overnight continuous positive airway pressure. Measurements and Results: Women with preeclampsia had inspiratory flow limitation and an increased number of oxygen desaturations during sleep (P = 0.008), particularly during REM sleep. Preeclampsia was associated with reduced total fetal movements overnight (319 [SD 32]) versus controls (689 [SD 160], P < 0.0001) and a change in fetal movement patterns. The number of fetal hiccups was also substantially reduced in preeclampsia subjects (P < 0.0001). Continuous positive airway pressure treatment increased the number of fetal movements and hiccups (P < 0.0001 and P = 0.0002, respectively). Conclusions: The effectiveness of continuous positive airway pressure in improving fetal movements suggests a pathogenetic role for sleep disordered breathing in the reduced fetal activity and possibly in the poorer fetal outcomes associated with preeclampsia. Citation: Blyton DM; Skilton MR; Edwards N; Hennessy A; Celermajer DS; Sullivan CE. Treatment of sleep disordered breathing reverses low fetal activity levels in preeclampsia. SLEEP 2013;36(1):15–21. PMID:23288967

Refining the Use of Nasal High-Flow Therapy as Primary Respiratory Support for Preterm Infants.

PubMed

Manley, Brett J; Roberts, Calum T; Frøisland, Dag H; Doyle, Lex W; Davis, Peter G; Owen, Louise S

2018-05-01

To identify clinical and demographic variables that predict nasal high-flow (nHF) treatment failure when used as a primary respiratory support for preterm infants. This secondary analysis used data from a multicenter, randomized, controlled trial comparing nHF with continuous positive airway pressure as primary respiratory support in preterm infants 28-36 completed weeks of gestation. Treatment success or failure with nHF was determined using treatment failure criteria within the first 72 hours after randomization. Infants in whom nHF treatment failed received continuous positive airway pressure, and were then intubated if failure criteria were again met. There were 278 preterm infants included, with a mean gestational age (GA) of 32.0 ± 2.1 weeks and a birth weight of 1737 ± 580 g; of these, nHF treatment failed in 71 infants (25.5%). Treatment failure was moderately predicted by a lower GA and higher prerandomization fraction of inspired oxygen (FiO 2 ): area under a receiver operating characteristic curve of 0.76 (95% CI, 0.70-0.83). Nasal HF treatment success was more likely in infants born at ≥30 weeks GA and with prerandomization FiO 2 <0.30. In preterm infants ≥28 weeks' GA enrolled in a randomized, controlled trial, lower GA and higher FiO 2 before randomization predicted early nHF treatment failure. Infants were more likely to be successfully treated with nHF from soon after birth if they were born at ≥30 weeks GA and had a prerandomization FiO 2 <0.30. However, even in this select population, continuous positive airway pressure remains superior to nHF as early respiratory support in preventing treatment failure. Australian New Zealand Clinical Trials Registry: ACTRN12613000303741. Copyright © 2018 Elsevier Inc. All rights reserved.

Optimal level of continuous positive airway pressure: auto-adjusting titration versus titration with a predictive equation.

PubMed

Choi, Ji Ho; Jun, Young Joon; Oh, Jeong In; Jung, Jong Yoon; Hwang, Gyu Ho; Kwon, Soon Young; Lee, Heung Man; Kim, Tae Hoon; Lee, Sang Hag; Lee, Seung Hoon

2013-05-01

The aims of the present study were twofold. We sought to compare two methods of titrating the level of continuous positive airway pressure (CPAP) - auto-adjusting titration and titration using a predictive equation - with full-night manual titration used as the benchmark. We also investigated the reliability of the two methods in patients with obstructive sleep apnea syndrome (OSAS). Twenty consecutive adult patients with OSAS who had successful, full-night manual and auto-adjusting CPAP titration participated in this study. The titration pressure level was calculated with a previously developed predictive equation based on body mass index and apnea-hypopnea index. The mean titration pressure levels obtained with the manual, auto-adjusting, and predictive equation methods were 9.0 +/- 3.6, 9.4 +/- 3.0, and 8.1 +/- 1.6 cm H2O,respectively. There was a significant difference in the concordance within the range of +/- 2 cm H2O (p = 0.019) between both the auto-adjusting titration and the titration using the predictive equation compared to the full-night manual titration. However, there was no significant difference in the concordance within the range of +/- 1 cm H2O (p > 0.999). When compared to full-night manual titration as the standard method, auto-adjusting titration appears to be more reliable than using a predictive equation for determining the optimal CPAP level in patients with OSAS.

Aerophagia and gastroesophageal reflux disease in patients using continuous positive airway pressure: a preliminary observation.

PubMed

Watson, Nathaniel F; Mystkowski, Sue K

2008-10-15

Aerophagia is a complication of continuous positive airway pressure (CPAP) therapy for sleep disordered breathing (SDB), whereupon air is forced into the stomach and bowel. Associated discomfort can result in CPAP discontinuation. We hypothesize that aerophagia is associated with gastroesophageal reflux disease (GERD) via mechanisms involving GERD related lower esophageal sphincter (LES) compromise. Twenty-two subjects with aerophagia and 22 controls, matched for age, gender, and body mass index, who were being treated with CPAP for SDB were compared in regard to clinical aspects of GERD, GERD associated habits, SDB severity as measured by polysomnography, and mean CPAP pressure. More subjects with aerophagia had symptoms of GERD (77.3% vs. 36.4%; p < 0.01) and were on GERD related medications (45.5% vs. 18.2%, p < 0.05) than controls. Regarding polysomnography, mean oxygen saturation percentages were lower in the aerophagia group than controls (95.0% vs. 96.5%, p < 0.05). No other differences were observed, including mean CPAP pressures. No one in the aerophagia group (vs. 27.3% of the control group) was a current tobacco user (p < 0.01). There was no difference in caffeine or alcohol use between the 2 groups. These results imply aerophagia is associated with GERD symptoms and GERD related medication use. This finding suggests a relationship between GERD related LES pathophysiology and the development of aerophagia in patients with SDB treated with CPAP.

Effects of Armodafinil on Simulated Driving and Self-Report Measures in Obstructive Sleep Apnea Patients prior to Treatment with Continuous Positive Airway Pressure

PubMed Central

Kay, Gary G.; Feldman, Neil

2013-01-01

Study Objectives: Obstructive sleep apnea (OSA) has been associated with an increased risk of motor vehicle crashes. This driving risk can be reduced (≥ 50%) by treatment with continuous positive airway pressure (CPAP). However residual excessive daytime sleepiness (EDS) can persist for some patients who regularly use CPAP. The current study was designed to assess the effect of armodafinil on simulated driving performance and subsequent CPAP treatment compliance in newly diagnosed OSA patients with EDS during a 2-week “waiting period” prior to initiation of CPAP. Methods: Sixty-nine newly diagnosed OSA patients, awaiting CPAP therapy, were randomized (1:1) to placebo or armodafinil (150 mg/day) treatment. Simulated driving tests and self-report measures were completed at baseline, after 2 weeks of drug treatment, and following 6 weeks of CPAP treatment. CPAP compliance was evaluated at the end of 6 weeks of CPAP. Results: Compared to placebo, armodafinil improved simulated driving safety performance in OSA patients awaiting CPAP therapy (p = 0.03). Improvement was seen in lane position deviation (p = 0.002) and number of lane excursions (p = 0.02). Improvement was also observed on measures of sleepiness using the Epworth Sleepiness Scale (ESS) and sleep related quality of life. Following 6 weeks of CPAP, there was also significant improvement observed on multiple measures of simulated driving performance. CPAP compliance did not differ between armodafinil-treated and placebo-treated patients (p = 0.80). Conclusions: Armodafinil was found to improve simulated driving performance in OSA patients with EDS prior to initiation of CPAP. Treatment with armodafinil showed no effect on subsequent CPAP compliance. Citation: Kay GG; Feldman N. Effects of armodafinil on simulated driving and self-report measures in obstructive sleep apnea patients prior to treatment with continuous positive airway pressure. J Clin Sleep Med 2013;9(5):445-454. PMID:23674935

Continuous positive airway pressure reduces blood pressure in patients with obstructive sleep apnea; a systematic review and meta-analysis with 1000 patients.

PubMed

Schein, Andressa S O; Kerkhoff, Alessandra C; Coronel, Christian C; Plentz, Rodrigo D M; Sbruzzi, Graciele

2014-09-01

Obstructive sleep apnea (OSA) may lead to the development of hypertension and therapy with continuous positive airway pressure (CPAP) can promote reduction in blood pressure. The objective of this study is to review systematically the effects of CPAP on blood pressure in patients with OSA. The search was conducted in the following databases, from their beginning until February 2013: MEDLINE, Embase, Cochrane CENTRAL, Lilacs and PEDro. In addition, a manual search was performed on references of published studies. Randomized clinical trials (RCTs) that used CPAP compared with placebo CPAP or subtherapeutic CPAP for treatment of patients with OSA and that evaluated office SBP and DBP and 24-h ambulatory blood pressure were selected. Sixteen RCTs were included among 3409 publications, totaling 1166 patients. The use of CPAP resulted in reductions in office SBP [-3.20  mmHg; 95% confidence interval (CI) -4.67 to -1.72] and DBP (-2.87  mmHg; 95% CI -5.18 to -0.55); in night-time SBP (-4.92  mmHg; 95% CI -8.70 to -1.14); in mean 24-h blood pressure (-3.56  mmHg; 95% CI -6.79 to -0.33), mean night-time blood pressure (-2.56  mmHg; 95% CI -4.43 to -0.68) and 24-h DBP (-3.46  mmHg; 95% CI -6.75 to -0.17). However, no significant change was observed in daytime SBP (-0.74  mmHg; 95% CI -3.90 to 2.41) and daytime DBP (-1.86  mmHg; 95% CI -4.55 to 0.83). Treatment with CPAP promoted significantly but small reductions in blood pressure in individuals with OSA. Further studies should be performed to evaluate the effects of long-term CPAP and the impact on cardiovascular risk.

Sleep-disordered breathing in patients with post-traumatic stress disorder.

PubMed

Jaoude, Philippe; Vermont, Leah N; Porhomayon, Jahan; El-Solh, Ali A

2015-02-01

Post-traumatic stress disorder (PTSD) and sleep-disordered breathing (SDB) are shared by many patients. They both affect sleep and the quality of life of affected subjects. A critical review of the literature supports an association between the two disorders in both combat-related and non-combat-related PTSD. The exact mechanism linking PTSD and SDB is not fully understood. A complex interplay between sleep fragmentation and neuroendocrine pathways is suggested. The overlap of symptoms between PTSD and SDB raises diagnostic challenges that may require a novel approach in the methods used to diagnose the coexisting disorders. Similar therapeutic challenges face patients and providers when treating concomitant PTSD and SDB. Although continuous positive airway pressure therapy imparts a mitigating effect on PTSD symptomatology, lack of both acceptance and adherence are common. Future research should focus on ways to improve adherence to continuous positive airway pressure therapy and on the use of alternative therapeutic methods for treating SDB in patients with PTSD.

Corneal Neovascularization with Associated Lipid Keratopathy in a Patient with Obstructive Sleep Apnea-Hypopnea Syndrome Using a Continuous Positive Airway Pressure Machine.

PubMed

Oikonomakis, Konstantinos; Petrelli, Myrsini; Andreanos, Konstantinos; Mouchtouris, Andreas; Petrou, Petros; Georgalas, Ilias; Papaconstantinou, Dimitrios; Kymionis, George

2017-01-01

To report a case of corneal neovascularization with secondary lipid keratopathy in a patient treated with continuous positive airway pressure (CPAP) for obstructive sleep apnea-hypopnea syndrome (OSAHS). A 49-year-old male had been diagnosed with obstructive sleep apnea syndrome 10 years ago and has been treated with the application of a CPAP machine during night sleep ever since. For the past year, the patient had been complaining for ocular irritation and excessive tearing of the left eye on awakening. Slit-lamp biomicroscopy revealed the presence of neovascularization and lipid exudation in the inferior third of the cornea of the left eye. Ocular patching during night sleep resulted in recession of the reported symptoms and shrinkage of the neovascularization, while the area of lipid exudation ceased to enlarge. To the best of our knowledge, this is the first report of corneal neovascularization in a patient using a CPAP machine for OSAHS.

An Autonomous, Low Cost Platform for Seafloor Geodetic Observations

NASA Astrophysics Data System (ADS)

Ericksen, T.; Foster, J. H.; Bingham, B. S.; Oshiro, J.

2014-12-01

The Pacific GPS Facility and the Field Robotics Laboratory at the University of Hawaii have developed an approach to significantly reduce costs below ship based methods of accurately measuring short-term vertical motions of the seafloor and maintaining a continuous long-term record of seafloor pressure. Our goal has been to reduce the primary barrier preventing us from acquiring the observations we need to understand geodetic processes, and the hazards they present, at subduction zones, submarine volcanoes, and subsea landslides. To this end, we have designed a payload package for one of the University of Hawaii Wave Gliders which incorporates an acoustic telemetry package, a dual frequency geodetic-grade Global Positioning System (GPS) receiver, meteorological sensors, processing computer, and cellular communications. The Wave Glider will interrogate high accuracy pressure sensors on the seafloor to maintain a near-continuous stream of pressure and temperature data. The seafloor geodetic monument seats a sensor capable of recording pressure, temperature, and sound velocity for a deployment duration of over 5 years with an acoustic modem for communications, and an integral acoustic release for recovery and replacement of batteries. The design of the geodetic monument allows for precise repositioning of the sensor to extend the pressure record beyond a single 5+ year deployment, and includes the capability to install a mobile pressure recorder for calibration of the linear drift of the continuous pressure sensor. We will present the design of the Wave Glider payload and seafloor geodetic monument, as well as a discussion of nearshore and offshore field tests and operational procedures. An assessment of our ability to determine cm-scale vertical seafloor motions will be made by integrating the seafloor pressure measurements recovered during field testing with independent measurements of sea surface pressure and sea surface height made by the sea surface payload.

Detecting the limits of bronchial closure methods in an animal model.

PubMed

Tezel, C; Urek, S; Keles, M; Kiral, H; Koşar, A; Dudu, C; Arman, B

2006-04-01

Bronchopleural fistula is a serious complication of major lung resections that may lead to mortality. An experimental animal model was designed to find out the safest bronchial closure method by comparing leakage rates under pressure. The tracheobronchial trees of 50 freshly dead sheep were prepared for either manual closure or closure with a stapler. After left pneumonectomy, the specimens were divided into five groups (n = 10); 3/0 Premilene suture was used with two "u" sutures + interrupted sutures in Group I; in Group II, 3/0 Premilene sutures with continuous horizontal mattress + over-over continuous sutures were used. In Group III and IV the same techniques were used with 3/0 Vicryl. A stapler was used in Group V. Specimens were intubated with an endotracheal tube, connected to a sphygmomanometer, and subsequently positioned under water. The pressure level at which we detected air bubbles indicated the limits of the technique. The median leakage pressure resistance was significantly lower in Group III (135 mm Hg) ( P = 0.001). The best results were achieved by using the continuous horizontal mattress + over-over continuous suture technique. No statistical significance difference was found between the stapler group, Groups I, II, and IV in terms of median leakage pressures. This trial suggests that manual suture closure using an appropriate technique and monofilament materials is as safe as the stapler.

An apparatus for altering the mechanical load of the respiratory system.

PubMed

Younes, M; Bilan, D; Jung, D; Kroker, H

1987-06-01

We describe an apparatus for altering the mechanical load against which the respiratory muscles operate in humans. A closed system incorporates a rolling seal spirometer. The spirometer piston shaft is coupled to a fast-responding linear actuator that develops force in proportion to desired command signals. The command signal may be flow (resistive loading or unloading), volume (elastic loading or unloading), constant voltage (continuous positive or negative pressure), or any external function. Combinations of loads can be applied. Logic circuits permit application of the load at specific times during the respiratory cycle, and the magnitude of the loads is continuously adjustable. Maximum pressure output is +/- 20 cmH2O. The apparatus permits loading or unloading over a range of ventilation extending from resting levels to those observed during high levels of exercise (over 100 l/min). In response to a square-wave input, pressure rises exponentially with a time constant of 20 ms.

Method for continuous control of composition and doping of pulsed laser deposited films

DOEpatents

Lowndes, Douglas H.; McCamy, James W.

1995-01-01

A method for growing a deposit upon a substrate of semiconductor material involves the utilization of pulsed laser deposition techniques within a low-pressure gas environment. The substrate and a target of a first material are positioned within a deposition chamber and a low-pressure gas atmosphere is developed within the chamber. The substrate is then heated, and the target is irradiated, so that atoms of the target material are ablated from the remainder of the target, while atoms of the gas simultaneously are adsorbed on the substrate/film surface. The ablated atoms build up upon the substrate, together with the adsorbed gas atoms to form the thin-film deposit on the substrate. By controlling the pressure of the gas of the chamber atmosphere, the composition of the formed deposit can be controlled, and films of continuously variable composition or doping can be grown from a single target of fixed composition.

Effects of 12 Months Continuous Positive Airway Pressure on Sympathetic Activity Related Brainstem Function and Structure in Obstructive Sleep Apnea

PubMed Central

Henderson, Luke A.; Fatouleh, Rania H.; Lundblad, Linda C.; McKenzie, David K.; Macefield, Vaughan G.

2016-01-01

Muscle sympathetic nerve activity (MSNA) is greatly elevated in patients with obstructive sleep apnea (OSA) during normoxic daytime wakefulness. Increased MSNA is a precursor to hypertension and elevated cardiovascular morbidity and mortality. However, the mechanisms underlying the high MSNA in OSA are not well understood. In this study we used concurrent microneurography and magnetic resonance imaging to explore MSNA-related brainstem activity changes and anatomical changes in 15 control and 15 OSA subjects before and after 6 and 12 months of continuous positive airway pressure (CPAP) treatment. We found that following 6 and 12 months of CPAP treatment, resting MSNA levels were significantly reduced in individuals with OSA. Furthermore, this MSNA reduction was associated with restoration of MSNA-related brainstem activity and structural changes in the medullary raphe, rostral ventrolateral medulla, dorsolateral pons, and ventral midbrain. This restoration occurred after 6 months of CPAP treatment and was maintained following 12 months CPAP. These findings show that continual CPAP treatment is an effective long-term treatment for elevated MSNA likely due to its effects on restoring brainstem structure and function. PMID:27013952

Water quality effects of intermittent water supply in Arraiján, Panama.

PubMed

Erickson, John J; Smith, Charlotte D; Goodridge, Amador; Nelson, Kara L

2017-05-01

Intermittent drinking water supply is common in low- and middle-income countries throughout the world and can cause water quality to degrade in the distribution system. In this study, we characterized water quality in one study zone with continuous supply and three zones with intermittent supply in the drinking water distribution network in Arraiján, Panama. Low or zero pressures occurred in all zones, and negative pressures occurred in the continuous zone and two of the intermittent zones. Despite hydraulic conditions that created risks for backflow and contaminant intrusion, only four of 423 (0.9%) grab samples collected at random times were positive for total coliform bacteria and only one was positive for E. coli. Only nine of 496 (1.8%) samples had turbidity >1.0 NTU and all samples had ≥0.2 mg/L free chlorine residual. In contrast, water quality was often degraded during the first-flush period (when supply first returned after an outage). Still, routine and first-flush water quality under intermittent supply was much better in Arraiján than that reported in a previous study conducted in India. Better water quality in Arraiján could be due to better water quality leaving the treatment plant, shorter supply outages, higher supply pressures, a more consistent and higher chlorine residual, and fewer contaminant sources near pipes. The results illustrate that intermittent supply and its effects on water quality can vary greatly between and within distribution networks. The study also demonstrated that monitoring techniques designed specifically for intermittent supply, such as continuous pressure monitoring and sampling the first flush, can detect water quality threats and degradation that would not likely be detected with conventional monitoring. Copyright © 2017 Elsevier Ltd. All rights reserved.

Blood Pressure Response to Losartan and Continuous Positive Airway Pressure in Hypertension and Obstructive Sleep Apnea.

PubMed

Thunström, Erik; Manhem, Karin; Rosengren, Annika; Peker, Yüksel

2016-02-01

Obstructive sleep apnea (OSA) is common in people with hypertension, particularly resistant hypertension. Treatment with an antihypertensive agent alone is often insufficient to control hypertension in patients with OSA. To determine whether continuous positive airway pressure (CPAP) added to treatment with an antihypertensive agent has an impact on blood pressure (BP) levels. During the initial 6-week, two-center, open, prospective, case-control, parallel-design study (2:1; OSA/no-OSA), all patients began treatment with an angiotensin II receptor antagonist, losartan, 50 mg daily. In the second 6-week, sex-stratified, open, randomized, parallel-design study of the OSA group, all subjects continued to receive losartan and were randomly assigned to either nightly CPAP as add-on therapy or no CPAP. Twenty-four-hour BP monitoring included assessment every 15 minutes during daytime hours and every 20 minutes during the night. Ninety-one patients with untreated hypertension underwent a home sleep study (55 were found to have OSA; 36 were not). Losartan significantly reduced systolic, diastolic, and mean arterial BP in both groups (without OSA: 12.6, 7.2, and 9.0 mm Hg; with OSA: 9.8, 5.7, and 6.1 mm Hg). Add-on CPAP treatment had no significant changes in 24-hour BP values but did reduce nighttime systolic BP by 4.7 mm Hg. All 24-hour BP values were reduced significantly in the 13 patients with OSA who used CPAP at least 4 hours per night. Losartan reduced BP in OSA, but the reductions were less than in no-OSA. Add-on CPAP therapy resulted in no significant changes in 24-hour BP measures except in patients using CPAP efficiently. Clinical trial registered with www.clinicaltrials.gov (NCT00701428).​

Optimizing lung aeration at birth using a sustained inflation and positive pressure ventilation in preterm rabbits

PubMed Central

te Pas, Arjan B.; Kitchen, Marcus J.; Lee, Katie; Wallace, Megan J.; Fouras, Andreas; Lewis, Robert A.; Yagi, Naoto; Uesugi, Kentaro; Hooper, Stuart B.

2016-01-01

Background: A sustained inflation (SI) facilitates lung aeration, but the most effective pressure and duration are unknown. We investigated the effect of gestational age (GA) and airway liquid volume on the required inflation pressure and SI duration. Methods: Rabbit kittens were delivered at 27, 29, and 30 d gestation, intubated and airway liquid was aspirated. Either no liquid (control) or 30 ml/kg of liquid was returned to the airways. Lung gas volumes were measured by plethysmography and phase-contrast X-ray-imaging. Starting at 22 cmH2O, airway pressure was increased until airflow commenced and pressure was then held constant. The SI was truncated when 20 ml/kg air had entered the lung and ventilation continued with intermittent positive pressure ventilation (iPPV). Results: Higher SI pressures and longer durations were required in 27-d kittens compared to 30-d kittens. During iPPV, 27-d kittens needed higher pressures and had lower functional residual capacity (FRC) compared to 30-d kittens. Adding lung liquid increased SI duration, reduced FRC, and increased resistance and pressures during iPPV in 29- and 30-d kittens. Conclusion: Immature kittens required higher starting pressures and longer SI durations to achieve a set inflation volume. Larger airway liquid volumes adversely affected lung function during iPPV in older but not young kittens. PMID:26991259

Type of Mask May Impact on Continuous Positive Airway Pressure Adherence in Apneic Patients

PubMed Central

Borel, Jean Christian; Tamisier, Renaud; Dias-Domingos, Sonia; Sapene, Marc; Martin, Francis; Stach, Bruno; Grillet, Yves; Muir, Jean François; Levy, Patrick; Series, Frederic; Pepin, Jean-Louis

2013-01-01

Rationale In obstructive sleep apnea patients (OSA), continuous positive airway pressure (CPAP) adherence is crucial to improve symptoms and cardiometabolic outcomes. The choice of mask may influence CPAP adherence but this issue has never been addressed properly. Objective To evaluate the impact of nasal pillows, nasal and oronasal masks on CPAP adherence in a cohort of OSA. Methods Newly CPAP treated OSA participating in “Observatoire Sommeil de la Fédération de Pneumologie”, a French national prospective cohort, were included between March 2009 and December 2011. Anthropometric data, medical history, OSA severity, sleepiness, depressive status, treatment modalities (auto-CPAP versus fixed pressure, pressure level, interface type, use of humidifiers) and CPAP-related side effects were included in multivariate analysis to determine independent variables associated with CPAP adherence. Results 2311 OSA (age = 57(12) years, apnea+hypopnea index = 41(21)/h, 29% female) were included. Nasal masks, oronasal masks and nasal pillows were used by 62.4, 26.2 and 11.4% of the patients, respectively. In univariate analysis, oronasal masks and nasal pillows were associated with higher risk of CPAP non-adherence. CPAP non-adherence was also associated with younger age, female gender, mild OSA, gastroesophageal reflux, depression status, low effective pressure and CPAP-related side effects. In multivariate analysis, CPAP non-adherence was associated with the use of oronasal masks (OR = 2.0; 95%CI = 1.6; 2.5), depression, low effective pressure, and side effects. Conclusion As oronasal masks negatively impact on CPAP adherence, a nasal mask should be preferred as the first option. Patients on oronasal masks should be carefully followed. PMID:23691209

Nasal continuous positive airway pressure (CPAP) for the respiratory care of the newborn infant.

PubMed

Diblasi, Robert M

2009-09-01

Nasal continuous positive airway pressure (CPAP) is a noninvasive form of respiratory assistance that has been used to support spontaneously breathing infants with lung disease for nearly 40 years. Following reports that mechanical ventilation contributes to pulmonary growth arrest and the development of chronic lung disease, there is a renewed interest in using CPAP as the prevailing method for supporting newborn infants. Animal and human research has shown that CPAP is less injurious to the lungs than is mechanical ventilation. The major concepts that embrace lung protection during CPAP are the application of spontaneous breathing at a constant distending pressure and avoidance of intubation and positive-pressure inflations. A major topic for current research focuses on whether premature infants should be supported initially with CPAP following delivery, or after the infant has been extubated following prophylactic surfactant administration. Clinical trials have shown that CPAP reduces the need for intubation/mechanical ventilation and surfactant administration, but it is still unclear whether CPAP reduces chronic lung disease and mortality, compared to modern lung-protective ventilation techniques. Despite the successes, little is known about how best to manage patients using CPAP. It is also unclear whether different strategies or devices used to maintain CPAP play a role in improving outcomes in infants. Nasal CPAP technology has evolved over the last 10 years, and bench and clinical research has evaluated differences in physiologic effects related to these new devices. Ultimately, clinicians' abilities to perceive changes in the pathophysiologic conditions of infants receiving CPAP and the quality of airway care provided are likely to be the most influential factors in determining patient outcomes.

Cryogenic wind tunnels: Problems of continuous operation at low temperatures

NASA Technical Reports Server (NTRS)

Faulmann, D.

1986-01-01

The design of a cryogenic wind tunnel which operates continuously, and is capable of attaining transonic speeds at generating pressures of about 3 bars is described. Its stainless steel construction with inside insulation allows for very rapid temperature variations promoted by rapid changes in the liquid nitrogen flow. A comparative study of temperature measuring probes shows a good reliability of thin sheet thermocouples. To measure fluctuations, only a cold wire makes it possible to record frequencies of about 300 Hz. The use of an integral computer method makes it possible to determine the impact of the wall temperature ratio to the adiabatic wall temperature for the various parameters characterizing the boundary layer. These cases are processed with positive and negative pressure gradients.

CPAP IMPACT: a protocol for a randomised trial of bubble continuous positive airway pressure versus standard care for high-risk children with severe pneumonia using adaptive design methods

PubMed Central

Smith, Andrew G; Eckerle, Michelle; Mvalo, Tisungane; Weir, Brian; Martinson, Francis; Chalira, Alfred; Lufesi, Norman; Mofolo, Innocent; Hosseinipour, Mina

2017-01-01

Introduction Pneumonia is a leading cause of mortality among children in low-resource settings. Mortality is greatest among children with high-risk conditions including HIV infection or exposure, severe malnutrition and/or severe hypoxaemia. WHO treatment recommendations include low-flow oxygen for children with severe pneumonia. Bubble continuous positive airway pressure (bCPAP) is a non-invasive support modality that provides positive end-expiratory pressure and oxygen. bCPAP is effective in the treatment of neonates in low-resource settings; its efficacy is unknown for high-risk children with severe pneumonia in low-resource settings. Methods and analysis CPAP IMPACT is a randomised clinical trial comparing bCPAP to low-flow oxygen in the treatment of severe pneumonia among high-risk children 1–59 months of age. High-risk children are stratified into two subgroups: (1) HIV infection or exposure and/or severe malnutrition; (2) severe hypoxaemia. The trial is being conducted in a Malawi district hospital and will enrol 900 participants. The primary outcome is in-hospital mortality rate of children treated with standard care as compared with bCPAP. Ethics and dissemination CPAP IMPACT has approval from the Institutional Review Boards of all investigators. An urgent need exists to determine whether bCPAP decreases mortality among high-risk children with severe pneumonia to inform resource utilisation in low-resource settings. Trial registration number NCT02484183; Pre-results. PMID:28883928

Practice parameters for the use of autotitrating continuous positive airway pressure devices for titrating pressures and treating adult patients with obstructive sleep apnea syndrome: an update for 2007. An American Academy of Sleep Medicine report.

PubMed

Morgenthaler, Timothy I; Aurora, R Nisha; Brown, Terry; Zak, Rochelle; Alessi, Cathy; Boehlecke, Brian; Chesson, Andrew L; Friedman, Leah; Kapur, Vishesh; Maganti, Rama; Owens, Judith; Pancer, Jeffrey; Swick, Todd J

2008-01-01

These practice parameters are an update of the previously published recommendations regarding the use of autotitrating positive airway pressure (APAP) devices for titrating pressures and treating adult patients with obstructive sleep apnea syndrome. Continuous positive airway pressure (CPAP) at an effective setting verified by attended polysomnography is a standard treatment for obstructive sleep apnea (OSA). APAP devices change the treatment pressure based on feedback from various patient measures such as airflow, pressure fluctuations, or measures of airway resistance. These devices may aid in the pressure titration process, address possible changes in pressure requirements throughout a given night and from night to night, aid in treatment of OSA when attended CPAP titration has not or cannot be accomplished, or improve patient comfort. A task force of the Standards of Practice Committee of the American Academy of Sleep Medicine has reviewed the literature published since the 2002 practice parameter on the use of APAP. Current recommendations follow: (1) APAP devices are not recommended to diagnose OSA; (2) patients with congestive heart failure, patients with significant lung disease such as chronic obstructive pulmonary disease; patients expected to have nocturnal arterial oxyhemoglobin desaturation due to conditions other than OSA (e.g., obesity hypoventilation syndrome); patients who do not snore (either naturally or as a result of palate surgery); and patients who have central sleep apnea syndromes are not currently candidates for APAP titration or treatment; (3) APAP devices are not currently recommended for split-night titration; (4) certain APAP devices may be used during attended titration with polysomnography to identify a single pressure for use with standard CPAP for treatment of moderate to severe OSA; (5) certain APAP devices may be initiated and used in the self-adjusting mode for unattended treatment of patients with moderate to severe OSA without significant comorbidities (CHF, COPD, central sleep apnea syndromes, or hypoventilation syndromes); (6) certain APAP devices may be used in an unattended way to determine a fixed CPAP treatment pressure for patients with moderate to severe OSA without significant comorbidities (CHF, COPD, central sleep apnea syndromes, or hypoventilation syndromes); (7) patients being treated with fixed CPAP on the basis of APAP titration or being treated with APAP must have close clinical follow-up to determine treatment effectiveness and safety; and (8) a reevaluation and, if necessary, a standard attended CPAP titration should be performed if symptoms do not resolve or the APAP treatment otherwise appears to lack efficacy.

Design and Validation of In-Source Atmospheric Pressure Photoionization Hydrogen/Deuterium Exchange Mass Spectrometry with Continuous Feeding of D2O.

PubMed

Acter, Thamina; Lee, Seulgidaun; Cho, Eunji; Jung, Maeng-Joon; Kim, Sunghwan

2018-01-01

In this study, continuous in-source hydrogen/deuterium exchange (HDX) atmospheric pressure photoionization (APPI) mass spectrometry (MS) with continuous feeding of D 2 O was developed and validated. D 2 O was continuously fed using a capillary line placed on the center of a metal plate positioned between the UV lamp and nebulizer. The proposed system overcomes the limitations of previously reported APPI HDX-MS approaches where deuterated solvents were premixed with sample solutions before ionization. This is particularly important for APPI because solvent composition can greatly influence ionization efficiency as well as the solubility of analytes. The experimental parameters for APPI HDX-MS with continuous feeding of D 2 O were optimized, and the optimized conditions were applied for the analysis of nitrogen-, oxygen-, and sulfur-containing compounds. The developed method was also applied for the analysis of the polar fraction of a petroleum sample. Thus, the data presented in this study clearly show that the proposed HDX approach can serve as an effective analytical tool for the structural analysis of complex mixtures. Graphical abstract ᅟ.

Markers of Successful Extubation in Extremely Preterm Infants, and Morbidity After Failed Extubation

PubMed Central

Chawla, Sanjay; Natarajan, Girija; Shankaran, Seetha; Carper, Benjamin; Brion, Luc P.; Keszler, Martin; Carlo, Waldemar A.; Ambalavanan, Namasivayam; Gantz, Marie G.; Das, Abhik; Finer, Neil; Goldberg, Ronald N.; Cotten, C. Michael; Higgins, Rosemary D.

2017-01-01

Objectives To identify variables associated with successful elective extubation, and to determine neonatal morbidities associated with extubation failure in extremely preterm neonates. Study design This study was a secondary analysis of the National Institute of Child Health and Human Development Neonatal Research Network’s Surfactant, Positive Pressure, and Oxygenation Randomized Trial that included extremely preterm infants born at 240/7 to 276/7 weeks’ gestation. Patients were randomized either to a permissive ventilatory strategy (continuous positive airway pressure group) or intubation followed by early surfactant (surfactant group). There were prespecified intubation and extubation criteria. Extubation failure was defined as reintubation within 5 days of extubation. Results Of 1316 infants in the trial, 1071 were eligible; 926 infants had data available on extubation status; 538 were successful and 388 failed extubation. The rate of successful extubation was 50% (188/374) in the continuous positive airway pressure group and 63% (350/552) in the surfactant group. Successful extubation was associated with higher 5-minute Apgar score, and pH prior to extubation, lower peak fraction of inspired oxygen within the first 24 hours of age and prior to extubation, lower partial pressure of carbon dioxide prior to extubation, and non-small for gestational age status after adjustment for the randomization group assignment. Infants who failed extubation had higher adjusted rates of mortality (OR 2.89), bronchopulmonary dysplasia (OR 3.06), and death/bronchopulmonary dysplasia (OR 3.27). Conclusions Higher 5-minute Apgar score, and pH prior to extubation, lower peak fraction of inspired oxygen within first 24 hours of age, lower partial pressure of carbon dioxide and fraction of inspired oxygen prior to extubation, and nonsmall for gestational age status were associated with successful extubation. Failed extubation was associated with significantly higher likelihood of mortality and morbidities. Trial registration ClinicalTrials.gov: NCT00233324. PMID:28600154

Markers of Successful Extubation in Extremely Preterm Infants, and Morbidity After Failed Extubation.

PubMed

Chawla, Sanjay; Natarajan, Girija; Shankaran, Seetha; Carper, Benjamin; Brion, Luc P; Keszler, Martin; Carlo, Waldemar A; Ambalavanan, Namasivayam; Gantz, Marie G; Das, Abhik; Finer, Neil; Goldberg, Ronald N; Cotten, C Michael; Higgins, Rosemary D

2017-10-01

To identify variables associated with successful elective extubation, and to determine neonatal morbidities associated with extubation failure in extremely preterm neonates. This study was a secondary analysis of the National Institute of Child Health and Human Development Neonatal Research Network's Surfactant, Positive Pressure, and Oxygenation Randomized Trial that included extremely preterm infants born at 24 0/7 to 27 6/7 weeks' gestation. Patients were randomized either to a permissive ventilatory strategy (continuous positive airway pressure group) or intubation followed by early surfactant (surfactant group). There were prespecified intubation and extubation criteria. Extubation failure was defined as reintubation within 5 days of extubation. Of 1316 infants in the trial, 1071 were eligible; 926 infants had data available on extubation status; 538 were successful and 388 failed extubation. The rate of successful extubation was 50% (188/374) in the continuous positive airway pressure group and 63% (350/552) in the surfactant group. Successful extubation was associated with higher 5-minute Apgar score, and pH prior to extubation, lower peak fraction of inspired oxygen within the first 24 hours of age and prior to extubation, lower partial pressure of carbon dioxide prior to extubation, and non-small for gestational age status after adjustment for the randomization group assignment. Infants who failed extubation had higher adjusted rates of mortality (OR 2.89), bronchopulmonary dysplasia (OR 3.06), and death/ bronchopulmonary dysplasia (OR 3.27). Higher 5-minute Apgar score, and pH prior to extubation, lower peak fraction of inspired oxygen within first 24 hours of age, lower partial pressure of carbon dioxide and fraction of inspired oxygen prior to extubation, and nonsmall for gestational age status were associated with successful extubation. Failed extubation was associated with significantly higher likelihood of mortality and morbidities. ClinicalTrials.gov: NCT00233324. Copyright © 2017 Elsevier Inc. All rights reserved.

40 CFR 63.11583 - What are my monitoring requirements?

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Area Sources: Chemical Preparations... methods described in paragraphs (a), (b) or (c) of this section while equipment within a chemical... applicable, and the following: (1) Locate the pressure sensor(s) in, or as close as possible to, a position...

40 CFR 63.11583 - What are my monitoring requirements?

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Area Sources: Chemical Preparations... methods described in paragraphs (a), (b) or (c) of this section while equipment within a chemical... applicable, and the following: (1) Locate the pressure sensor(s) in, or as close as possible to, a position...

40 CFR 63.11583 - What are my monitoring requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Area Sources: Chemical Preparations... methods described in paragraphs (a), (b) or (c) of this section while equipment within a chemical... applicable, and the following: (1) Locate the pressure sensor(s) in, or as close as possible to, a position...

14 CFR 382.3 - What do the terms in this rule mean?

Code of Federal Regulations, 2011 CFR

2011-01-01

... and places between which those flights are performed. CPAP machine means a continuous positive airway pressure machine. Department or DOT means the United States Department of Transportation. Direct threat... learning disabilities. The term physical or mental impairment includes, but is not limited to, such...

14 CFR 382.3 - What do the terms in this rule mean?

Code of Federal Regulations, 2014 CFR

2014-01-01

... devices and medications. Automated airport kiosk means a self-service transaction machine that a carrier... machine means a continuous positive airway pressure machine. Department or DOT means the United States..., emotional or mental illness, and specific learning disabilities. The term physical or mental impairment...

14 CFR 382.3 - What do the terms in this rule mean?

Code of Federal Regulations, 2012 CFR

2012-01-01

... and places between which those flights are performed. CPAP machine means a continuous positive airway pressure machine. Department or DOT means the United States Department of Transportation. Direct threat... learning disabilities. The term physical or mental impairment includes, but is not limited to, such...

14 CFR 382.3 - What do the terms in this rule mean?

Code of Federal Regulations, 2013 CFR

2013-01-01

... and places between which those flights are performed. CPAP machine means a continuous positive airway pressure machine. Department or DOT means the United States Department of Transportation. Direct threat... learning disabilities. The term physical or mental impairment includes, but is not limited to, such...

Elevated levels of endothelial cell-derived microparticles following short-term withdrawal of continuous positive airway pressure in patients with obstructive sleep apnea: data from a randomized controlled trial.

PubMed

Ayers, Lisa; Stoewhas, Anne-Christin; Ferry, Berne; Stradling, John; Kohler, Malcolm

2013-01-01

Obstructive sleep apnea has been associated with impaired endothelial function; however, the mechanisms underlying this association are not completely understood. Cell-derived microparticles may provide a link between obstructive sleep apnea and endothelial dysfunction. This randomized controlled trial aimed to examine the effect of a 2-week withdrawal of continuous positive airway pressure (CPAP) therapy on levels of circulating microparticles. Forty-one obstructive sleep apnea patients established on CPAP treatment were randomized to either CPAP withdrawal (subtherapeutic CPAP) or continuing therapeutic CPAP, for 2 weeks. Polysomnography was performed and circulating levels of microparticles were analyzed by flow cytometry at baseline and 2 weeks. CPAP withdrawal led to a recurrence of obstructive sleep apnea. Levels of CD62E+ endothelium-derived microparticles increased significantly in the CPAP withdrawal group compared to the continuing therapeutic CPAP group (median difference in change +32.4 per µl; 95% CI +7.3 to +64.1 per µl, p = 0.010). CPAP withdrawal was not associated with a statistically significant increase in granulocyte, leukocyte, and platelet-derived microparticles when compared with therapeutic CPAP. Short-term withdrawal of CPAP therapy leads to a significant increase in endothelium-derived microparticles, suggesting that microparticle formation may be causally linked to obstructive sleep apnea and may promote endothelial activation. Copyright © 2012 S. Karger AG, Basel.

Non-surgical treatment of obstructive sleep apnea syndrome.

PubMed

Tingting, Xu; Danming, You; Xin, Chen

2018-02-01

Obstructive sleep apnea syndrome (OSAS), a pervasive disease, is closely associated with complications such as cardiovascular diseases, neurocognitive diseases, and metabolic syndromes. Continuous positive airway pressure (CPAP) is the standard treatment for OSAS, with low compliance due to multifarious factors. The two other modes of ventilation, bi-level positive airway pressure (BPAP) and autotitrating positive airway pressure (APAP), which were developed from CPAP, are slightly different from CPAP in specific groups, as well as the corresponding treatment effect and compliance. The compliance of traditional positional therapy is not high, but with the emergence of the neck-based position treatment device, its compliance and indications have changed. Although CPAP is superior to mandibular advancement device (MAD) in improving AHI, MAD seems to be comparable to CPAP in improving other indicators. Corticosteroids and leukotriene receptor antagonists are effective treatments for mild OSAS children. Whether corticosteroids can be used in other OSAS groups and their adjunctive functions to CPAP remains unclear. The combination of these two kinds of drugs appears to be more effective than single drug. Researches on transcutaneous electrical stimulation are still not enough. Its effectiveness and stimulation settings still need further study. This review summarized the various OSAS non-surgical treatments from indications, treatment outcomes, compliance, adverse reactions, and recent progress.

Accuracy of continuous noninvasive arterial pressure monitoring in living-liver donors during transplantation.

PubMed

Araz, Coskun; Zeyneloglu, Pinar; Pirat, Arash; Veziroglu, Nukhet; Camkiran Firat, Aynur; Arslan, Gulnaz

2015-04-01

Hemodynamic monitoring is vital during liver transplant surgeries because distinct hemodynamic changes are expected. The continuous noninvasive arterial pressure (CNAP) monitor is a noninvasive device for continuous arterial pressure measurement by a tonometric method. This study compared continuous noninvasive arterial pressure monitoring with invasive direct arterial pressure monitoring in living-liver donors during transplant. There were 40 patients analyzed while undergoing hepatic lobectomy for liver transplant. Invasive pressure monitoring was established at the radial artery and continuous noninvasive arterial pressure monitoring using a finger sensor was recorded simultaneously from the contralateral arm. Systolic, diastolic, and mean arterial pressures from the 2 methods were compared. Correlation between the 2 methods was calculated. A total of 5433 simultaneous measurements were obtained. For systolic arterial blood pressure, 55% continuous noninvasive arterial pressure measurements were within 10% direct arterial measurement; the correlation was 0.479, continuous noninvasive arterial pressure bias was -0.3 mm Hg, and limits of agreement were 32.0 mm Hg. For diastolic arterial blood pressure, 50% continuous noninvasive arterial pressure measurements were within 10% direct arterial measurement; the correlation was 0.630, continuous noninvasive arterial pressure bias was -0.4 mm Hg, and limits of agreement were 21.1 mm Hg. For mean arterial blood pressure, 60% continuous noninvasive arterial pressure measurements were within 10% direct arterial measurement; the correlation was 0.692, continuous noninvasive arterial pressure bias was +0.4 mm Hg, and limits of agreement were 20.8 mm Hg. The 2 monitoring techniques did not show acceptable agreement. Our results suggest that continuous noninvasive arterial pressure monitoring is not equivalent to invasive arterial pressure monitoring in donors during living-donor liver transplant.

Positive pressure ventilation in the management of acute and chronic cardiac failure: a systematic review and meta-analysis.

PubMed

Nadar, Sunil; Prasad, Neeraj; Taylor, Rod S; Lip, Gregory Y H

2005-03-18

Chronic heart failure (CHF) is a common condition and is associated with excess morbidity and mortality, in spite of the many advances in its treatment. Chronic stable heart failure is also associated with an increased incidence of sleep-related breathing disorders, such as central sleep apnoea (CSA) and Cheyne Stokes respiration (CSR). Continuous positive airways pressure (CPAP) has been shown to alleviate the symptoms of CHF, improve left ventricular function and oxygenation. To a certain extent, CPAP also abolishes sleep-related breathing disorders in patients with chronic heart failure. In patients with acute pulmonary oedema, the use of positive pressure ventilation improves cardiac haemodynamic indices, as well as symptoms and oxygenation, and is associated with a lower need for intubation. However, some studies have cast doubts about its safety and suggest a higher rate of myocardial infarction associated with its use. In our opinion, non-invasive positive pressure ventilation and CPAP offers an adjunctive mode of therapy in patients with acute pulmonary oedema and chronic heart failure, who may not be suitable for intubation and in those not responsive to conventional therapies. Non-invasive ventilation also helps to improve oxygenation in those patients with exhaustion and respiratory acidosis. Many trials are still ongoing and the results of these studies would throw more light on the present role of non-invasive ventilation in the management of CHF.

Magnetization and Hall effect under high pressure in NaV 6O 11

NASA Astrophysics Data System (ADS)

Naka, T.; Matsumoto, T.; Kanke, Y.; Murata, K.

1995-02-01

We have investigated the pressure dependences of magnetization and the Hall coefficient in the ferromagnetic vanadium oxide NaV 6O 11 up to 1.2 GPa. Structural transitions (hexagonal-hexagonal-orthorhombic) occur at TH = 245 K and TL = 35 K at ambient pressure. Meanwhile, the susceptibility obeys the Curie-Weiss law X = C/( T - θ) with antiferromagnetic correlation of θ < 0 at T > TH, with ferromagnetic correlation of θ < 0 at T < TH. The spontaneous magnetization appears below Tc = 64.2 K. With increasing pressure, Tc and magnetization M( T < Tc) decrease, while TH increases. The sign of the Hall coefficient changes continuously (negative-positive-negative) at around T ≈ 170 K and 75 K.

Strategies for maximizing your chances for weaning success. Limitations--and advantages--of common predictive indices.

PubMed

Patel, R G; Petrini, M F; Norman, J R

1995-06-01

Using indices to predict weaning outcome can avoid premature extubation and unnecessary prolongation of ventilatory support. Unfortunately, none of the indices is consistently able to predict outcome. The key to successful weaning is to assess respiratory function repeatedly with several indices, not just one. The patient should be able to sustain spontaneous breathing for at least 24 hours on minimal partial ventilatory support (a pressure support or a continuous positive airway pressure of 5 cm H2O or a T piece, for example). Indices of maximal inspiratory pressure; work of breathing; and rapid, shallow breathing are useful in evaluating a patient's respiratory muscle performance; airway occlusion pressure is helpful as well when increased neuromuscular drive is a problem.

Transtracheal oxygen and positive airway pressure: A salvage technique in overlap syndrome.

PubMed

Biscardi, Frank Hugo; Rubio, Edmundo Raul

2014-01-01

The coexistence of sleep apnea-hypopnea syndrome (SAHS) with chronic obstructive pulmonary disease (COPD) occurs commonly. This so called overlap syndrome leads to more profound hypoxemia, hypercapnic respiratory failure, and pulmonary hypertension than each of these conditions independently. Not infrequently, these patients show profound hypoxemia, despite optimal continuous positive airway pressure (CPAP) therapy for their SAHS. We report a case where CPAP therapy with additional in-line oxygen supplementation failed to accomplish adequate oxygenation. Adding transtracheal oxygen therapy (TTOT) to CPAP therapy provided better results. We review the literature on transtracheal oxygen therapy and how this technique may play a significant role in these complicated patients with overlap syndrome, obviating the need for more invasive procedures, such as tracheostomy.

Impact of Randomization, Clinic Visits, and Medical and Psychiatric Cormorbidities on Continuous Positive Airway Pressure Adherence in Obstructive Sleep Apnea

PubMed Central

Budhiraja, Rohit; Kushida, Clete A.; Nichols, Deborah A.; Walsh, James K.; Simon, Richard D.; Gottlieb, Daniel J.; Quan, Stuart F.

2016-01-01

Study Objectives: To evaluate factors associated with continuous positive airway pressure (CPAP) adherence in patients with obstructive sleep apnea (OSA) in the Apnea Positive Pressure Long-term Efficacy Study (APPLES) cohort. Methods: The data from a prospective 6-mo multicenter randomized controlled trial with 558 subjects randomized to active CPAP and 547 to sham CPAP were analyzed to assess adherence to CPAP during first 2 mo (early period) and during months 5-6 (late period). Results: Participants randomized to active CPAP had higher hours of nightly adherence compared to the sham CPAP group at both 2 (4.9 ± 2.0 h versus 4.07 ± 2.14 h, p < 0.001) and 6 mo (4.70 ± 2.08 h versus 3.41 ± 2.19 h, p < 0.001). Those assigned to sham CPAP were more likely to correctly identify their treatment group (70.0% versus 55.2%, p < 0.001). Irrespective of treatment group assignment, those who believed they were receiving active CPAP had higher hours of adherence than those who thought they were in the sham CPAP group at both 2 mo (4.91 ± 2.01 versus 4.17 ± 2.17, p < 0.001) and 6 mo (4.65 ± 2.10 versus 3.65 ± 2.22, p < 0.001). Among those randomized to active CPAP, older age was significantly related to CPAP use > 4 h per night. Presence of cardiovascular disorders was associated with higher hours of CPAP use, whereas presence of anxiety was associated with a trend toward lower hours of CPAP use. Presence of nasal congestion was associated with a decrease in mean daily CPAP use between the early and the late adherence period. The adherence during the week prior to a clinic visit was higher than the average adherence during the 2-mo period prior to the visit. Conclusions: Randomization to active therapy, belief that one is in the active treatment group, older age, and possibly presence of cardiovascular disorders are positively linked to CPAP adherence. Nasal congestion and anxiety are negatively associated with CPAP adherence. CPAP nightly usage increases as clinic visits approach. Citation: Budhiraja R, Kushida CA, Nichols DA, Walsh JK, Simon RD, Gottlieb DJ, Quan SF. Impact of randomization, clinic visits, and medical and psychiatric cormorbidities on continuous positive airway pressure adherence in obstructive sleep apnea. J Clin Sleep Med 2016;12(3):333–341. PMID:26518698

Mini Versus Standard Percutaneous Nephrolithotomy: The Impact of Sheath Size on Intrarenal Pelvic Pressure and Infectious Complications in a Porcine Model.

PubMed

Loftus, Christopher J; Hinck, Bryan; Makovey, Iryna; Sivalingam, Sri; Monga, Manoj

2018-04-01

To determine how sheath and endoscope size affect intrarenal pelvic pressures and risk of postoperative infectious complications comparing "Mini" vs "Standard" percutaneous nephrolithotomy (PCNL). Uropathogenic Escherichia coli were grown and 10 9 of them were instilled into the porcine renal pelvis through retrograde access for 1 hour. Percutaneous access utilized a 14/16F 20 cm ureteral access sheath for the Mini arm and a 30F sheath for the Standard arm. Nephroscopy was simulated utilizing either an 8/9.8F semirigid ureteroscope or 26F nephroscope for 1 hour while intrarenal pelvic pressure was continuously monitored. Blood and tissue cultures of kidney, liver, and spleen biopsies were plated and incubated and positive cultures were confirmed with polymerase chain reaction. Intrapelvic pressures were higher in the Mini group, 18.76 ± 5.82 mm Hg vs 13.56 ± 5.82 mm Hg (p < 0.0001). Time spent above 30 mm Hg was greater in the Mini arm, 117.0 seconds vs 66.1 seconds (p = 0.0452). All pigs had positive kidney tissue cultures whereas spleen cultures were positive in 100% and 60% of pigs in the Mini and Standard arms, respectively (p = 0.0253); 90% and 30% had positive liver tissue culture in the Mini and Standard arms, respectively (p = 0.0062). Blood cultures were positive in 30% of pigs in the Mini arm compared with none in the Standard arm (p = 0.0603). Mini-PCNL was associated with higher intrarenal pressures and higher risk of end organ bacterial seeding in the setting of an infected collecting system. This suggests a higher potential for infectious complications in a clinical setting.

Continuous positive airway pressure and ventilation are more effective with a nasal mask than a full face mask in unconscious subjects: a randomized controlled trial.

PubMed

Oto, Jun; Li, Qian; Kimball, William R; Wang, Jingping; Sabouri, Abdolnabi S; Harrell, Priscilla G; Kacmarek, Robert M; Jiang, Yandong

2013-12-23

Upper airway obstruction (UAO) is a major problem in unconscious subjects, making full face mask ventilation difficult. The mechanism of UAO in unconscious subjects shares many similarities with that of obstructive sleep apnea (OSA), especially the hypotonic upper airway seen during rapid eye movement sleep. Continuous positive airway pressure (CPAP) via nasal mask is more effective at maintaining airway patency than a full face mask in patients with OSA. We hypothesized that CPAP via nasal mask and ventilation (nCPAP) would be more effective than full face mask CPAP and ventilation (FmCPAP) for unconscious subjects, and we tested our hypothesis during induction of general anesthesia for elective surgery. In total, 73 adult subjects requiring general anesthesia were randomly assigned to one of four groups: nCPAP P0, nCPAP P5, FmCPAP P0, and FmCPAP P5, where P0 and P5 represent positive end-expiratory pressure (PEEP) 0 and 5 cm H2O applied prior to induction. After apnea, ventilation was initiated with pressure control ventilation at a peak inspiratory pressure over PEEP (PIP/PEEP) of 20/0, then 20/5, and finally 20/10 cm H2O, each applied for 1 min. At each pressure setting, expired tidal volume (Vte) was calculated by using a plethysmograph device. The rate of effective tidal volume (Vte > estimated anatomical dead space) was higher (87.9% vs. 21.9%; P<0.01) and the median Vte was larger (6.9 vs. 0 mL/kg; P<0.01) with nCPAP than with FmCPAP. Application of CPAP prior to induction of general anesthesia did not affect Vte in either approach (nCPAP pre- vs. post-; 7.9 vs. 5.8 mL/kg, P = 0.07) (FmCPAP pre- vs. post-; 0 vs. 0 mL/kg, P = 0.11). nCPAP produced more effective tidal volume than FmCPAP in unconscious subjects. ClinicalTrials.gov identifier: NCT01524614.

Work of breathing using different interfaces in spontaneous positive pressure ventilation: helmet, face-mask, and endotracheal tube.

PubMed

Oda, Shinya; Otaki, Kei; Yashima, Nozomi; Kurota, Misato; Matsushita, Sachiko; Kumasaka, Airi; Kurihara, Hutaba; Kawamae, Kaneyuki

2016-08-01

Noninvasive positive pressure ventilation (NPPV) using a helmet is expected to cause inspiratory trigger delay due to the large collapsible and compliant chamber. We compared the work of breathing (WOB) of NPPV using a helmet or a full face-mask with that of invasive ventilation by tracheal intubation. We used a lung model capable of simulating spontaneous breathing (LUNGOO; Air Water Inc., Japan). LUNGOO was set at compliance (C) = 50 mL/cmH2O and resistance (R) = 5 cmH2O/L/s for normal lung simulation, C = 20 mL/cmH2O and R = 5 cmH2O/L/s for restrictive lung, and C = 50 mL/cmH2O and R = 20 cmH2O/L/s for obstructive lung. Muscle pressure was fixed at 25 cmH2O and respiratory rate at 20 bpm. Pressure support ventilation and continuous positive airway pressure were performed with each interface placed on a dummy head made of reinforced plastic that was connected to LUNGOO. We tested the inspiratory WOB difference between the interfaces with various combinations of ventilator settings (positive end-expiratory pressure 5 cmH2O; pressure support 0, 5, and 10 cmH2O). In the normal lung and restrictive lung models, WOB decreased more with the face-mask than the helmet, especially when accompanied by the level of pressure support. In the obstructive lung model, WOB with the helmet decreased compared with the other two interfaces. In the mixed lung model, there were no significant differences in WOB between the three interfaces. NPPV using a helmet is more effective than the other interfaces for WOB in obstructive lung disease.

Responses to negative pressure surrounding the neck in anesthetized animals.

PubMed

Wolin, A D; Strohl, K P; Acree, B N; Fouke, J M

1990-01-01

Continuous positive pressure applied at the nose has been shown to cause a decrease in upper airway resistance. The present study was designed to determine whether a similar positive transmural pressure gradient, generated by applying a negative pressure at the body surface around the neck, altered upper airway patency. Studies were performed in nine spontaneously breathing anesthetized supine dogs. Airflow was measured with a pneumotachograph mounted on an airtight muzzle placed over the nose and mouth of each animal. Upper airway pressure was measured as the differential pressure between the extrathoracic trachea and the inside of the muzzle. Upper airway resistance was monitored as an index of airway patency. Negative pressure (-2 to -20 cmH2O) was applied around the neck by using a cuirass extending from the jaw to the thorax. In each animal, increasingly negative pressures were transmitted to the airway wall in a progressive, although not linear, fashion. Decreasing the pressure produced a progressive fall in upper airway resistance, without causing a significant change in respiratory drive or respiratory timing. At -5 cmH2O pressure, there occurred a significant fall in upper airway resistance, comparable with the response of a single, intravenous injection of sodium cyanide (0.5-3.0 mg), a respiratory stimulant that produces substantial increases in respiratory drive. We conclude that upper airway resistance is influenced by the transmural pressure across the airway wall and that such a gradient can be accomplished by making the extraluminal pressure more negative.(ABSTRACT TRUNCATED AT 250 WORDS)

Bubble inductors: Pneumatic tuning of a stretchable inductor

NASA Astrophysics Data System (ADS)

Lazarus, Nathan; Bedair, Sarah S.

2018-05-01

From adaptive matching networks in power systems to channel selectable RF filters and circuitry, tunable inductors are fundamental components for circuits requiring reconfigurability. Here we demonstrate a new continuously tunable inductor based on physically stretching the inductor traces themselves. Liquid-metal-based stretchable conductors are wrapped around a pneumatic bubble actuator, allowing the inductor to be collapsed or expanded by application of pressure. In vacuum the bubble collapses, bringing the loop area to nearly zero, while positive pressure brings a dramatic increase in area and loop inductance. Using this approach, the inductor demonstrated in this work was able to achieve a tuning ratio of 2.6 with 1-2 second response time. With conductors available that can stretch by hundreds of percent, this technique is promising for very large tuning ratios in continuously tunable inductors.

Behavioral economics strategies for promoting adherence to sleep interventions.

PubMed

Stevens, Jack

2015-10-01

Cognitive-behavioral treatment for insomnia and continuous positive airway pressure therapy for obstructive sleep apnea are among the most efficacious sleep interventions. Unfortunately, adherence levels are disappointingly low for these interventions. Behavioral economics offers a promising framework for promoting adherence, often through relatively brief and straightforward strategies. The assumptions, goals, and key strategies of behavioral economics will be introduced. These strategies include providing social norms information, changing defaults, using the compromise effect, utilizing commitment devices, and establishing lottery-based systems. Then, this review will highlight specific behavioral economic approaches to promote patient adherence for three major sleep interventions: 1) behavioral treatment for pediatric insomnia, 2) cognitive-behavioral treatment for adult insomnia, and 3) continuous positive airway pressure for obstructive sleep apnea. Next, behavioral economic strategies will be discussed as ways to improve health care provider adherence to clinical practice guidelines regarding appropriate prescribing of hypnotics and ordering sleep-promoting practices for hospitalized inpatients. Finally, possible concerns that readers may have about behavioral economics strategies, including their efficacy, feasibility, and sustainability, will be addressed. Copyright © 2014 Elsevier Ltd. All rights reserved.

The role of telemedicine in obstructive sleep apnea management.

PubMed

Lugo, Vera; Villanueva, Jair Asir; Garmendia, Onintza; Montserrat, Josep M

2017-09-01

Obstructive sleep apnea (OSA) is a common disease that leads in notorious symptoms and comorbidities. Although general measures are important, continuous positive airway pressure (CPAP) is the best treatment option. However, compliance can be suboptimal and telemedicine may play a role to improve it. Areas covered: Review authors searched EMBASE, PubMed and Cochrane data bases using the following keywords: continuous positive airway pressure, Obstructive sleep apnea, telemedicine, respiratory telemedicine, information and communication technology. Papers published between 2000 and 2016 in English language were considered. Expert commentary: To improve OSA management, there is a pressing need to develop new cost-effective strategies, particularly those related to OSA treatment, from measures such as lifestyle changes to CPAP use. Two broad strategies should be implemented: 1) adequate pre-, peri-, and post-titration measures to ensure correct diagnosis, adequate training, and appropriate support during follow up; and 2) the use of technological advances including both the optimization of CPAP devices and the use of telemedicine, specially focused on the first days or weeks of treatment. Telemedicine can help with these processes, especially when it is personalized to the needs of each patient group.

Pulmonary Drug Delivery Following Continuous Vibrating Mesh Nebulization and Inspiratory Synchronized Vibrating Mesh Nebulization During Noninvasive Ventilation in Healthy Volunteers.

PubMed

Michotte, Jean-Bernard; Staderini, Enrico; Aubriot, Anne-Sophie; Jossen, Emilie; Dugernier, Jonathan; Liistro, Giuseppe; Reychler, Gregory

2018-02-01

A breath-synchronized nebulization option that could potentially improve drug delivery during noninvasive positive pressure ventilation (NIPPV) is currently not available on single-limb circuit bilevel ventilators. The aim of this study was to compare urinary excretion of amikacin following aerosol delivery with a vibrating mesh nebulizer coupled to a single-limb circuit bilevel ventilator, using conventional continuous (Conti-Neb) and experimental inspiratory synchronized (Inspi-Neb) nebulization modes. A crossover clinical trial involving 6 noninvasive ventilated healthy volunteers (mean age of 32.3 ± 9.5 y) randomly assigned to both vibrating mesh nebulization modes was conducted: Inspi-Neb delivered aerosol during only the whole inspiratory phase, whereas Conti-Neb delivered aerosol continuously. All subjects inhaled amikacin solution (500 mg/4 mL) during NIPPV using a single-limb bilevel ventilator (inspiratory positive airway pressure: 12 cm H 2 O, and expiratory positive airway pressure: 5 cm H 2 O). Pulmonary drug delivery of amikacin following both nebulization modes was compared by urinary excretion of drug for 24 hours post-inhalation. The total daily amount of amikacin excreted in the urine was significantly higher with Inspi-Neb (median: 44.72 mg; interquartile range [IQR]: 40.50-65.13) than with Conti-Neb (median: 40.07 mg; IQR: 31.00-43.73), (p = 0.02). The elimination rate constant of amikacin (indirect measure of the depth of drug penetration into the lungs) was significantly higher with Inspi-Neb (median: 0.137; IQR: 0.113-0.146) than with Conti-Neb (median: 0.116; IQR: 0.105-0.130), (p = 0.02). However, the mean pulmonary drug delivery rate, expressed as the ratio between total daily urinary amount of amikacin and nebulization time, was significantly higher with Conti-Neb (2.03 mg/min) than with Inspi-Neb (1.09 mg/min) (p < 0.01). During NIPPV with a single-limb circuit bilevel ventilator, the use of inspiratory synchronized vibrating mesh nebulization may improve pulmonary drug delivery compared with conventional continuous vibrating mesh nebulization.

[ARDS and severe brain injury. Therapeutic strategies in conflict].

PubMed

Bein, T; Kuhr, L P; Metz, C; Woertgen, C; Philipp, A; Taeger, K

2002-07-01

The development of adult respiratory distress syndrome (ARDS) complicates the treatment of patients with severe head injury, since special therapeutic strategies for both conditions might lead to a "conflict of interest". We report on the intensive care treatment of a young man who suffered severe brain injury (Glasgow Coma Scale = 3) due to a traffic accident and simultaneously developed ARDS from the aspiration of gastric content. We performed extensive monitoring of cerebral hemodynamics and metabolism (intracranial pressure measurement, jugular bulb oxymetry, estimation of arterial-jugular bulb lactate concentration difference) to prevent cerebral hypoxia and to control cerebral hyperemia. The application of a "lung protective strategy" with "permissive hypercapnia" led to a conflict, since the development of cranial hyperemia combined with cranial hypertension a few days after trauma, warranted the concept of controlled, temporary hyperventilation. Therefore, we applied a pumpless extracorporeal lung assist to improve carbon dioxide elimination. Furthermore, we started the ventilation in the prone position, since arterial oxygenation continued to deteriorate, although there is a lack of data describing the effect of a prone position on acute cerebral injury. Positioning the patient prone, we observed a prompt increase in intracranial pressure, which resulted in pharmacological intervention (mannitol). Treating the patient by intermittent prone position, by continuous extracorporeal lung assist and aerosolized prostacyclin administration in the following period, lung function improved and ARDS was treated successfully. After withdrawing the analgo-sedation the patient's vigilance rose continuously. The patient was transferred to a rehabilitation ward 33 days after admission to the intensive care unit. The combination of ARDS and severe brain injury needs special treatment, which includes extensive monitoring techniques to find a solution for therapeutic conflicts.

Effect of Nasal Obstruction on Continuous Positive Airway Pressure Treatment: Computational Fluid Dynamics Analyses

PubMed Central

Wakayama, Tadashi; Suzuki, Masaaki; Tanuma, Tadashi

2016-01-01

Objective Nasal obstruction is a common problem in continuous positive airway pressure (CPAP) therapy for obstructive sleep apnea and limits treatment compliance. The purpose of this study is to model the effects of nasal obstruction on airflow parameters under CPAP using computational fluid dynamics (CFD), and to clarify quantitatively the relation between airflow velocity and pressure loss coefficient in subjects with and without nasal obstruction. Methods We conducted an observational cross-sectional study of 16 Japanese adult subjects, of whom 9 had nasal obstruction and 7 did not (control group). Three-dimensional reconstructed models of the nasal cavity and nasopharynx with a CPAP mask fitted to the nostrils were created from each subject’s CT scans. The digital models were meshed with tetrahedral cells and stereolithography formats were created. CPAP airflow simulations were conducted using CFD software. Airflow streamlines and velocity contours in the nasal cavities and nasopharynx were compared between groups. Simulation models were confirmed to agree with actual measurements of nasal flow rate and with pressure and flow rate in the CPAP machine. Results Under 10 cmH2O CPAP, average maximum airflow velocity during inspiration was 17.6 ± 5.6 m/s in the nasal obstruction group but only 11.8 ± 1.4 m/s in the control group. The average pressure drop in the nasopharynx relative to inlet static pressure was 2.44 ± 1.41 cmH2O in the nasal obstruction group but only 1.17 ± 0.29 cmH2O in the control group. The nasal obstruction and control groups were clearly separated by a velocity threshold of 13.5 m/s, and pressure loss coefficient threshold of approximately 10.0. In contrast, there was no significant difference in expiratory pressure in the nasopharynx between the groups. Conclusion This is the first CFD analysis of the effect of nasal obstruction on CPAP treatment. A strong correlation between the inspiratory pressure loss coefficient and maximum airflow velocity was found. PMID:26943335

Closed-loop helium circulation system for actuation of a continuously operating heart catheter pump.

PubMed

Karabegovic, Alen; Hinteregger, Markus; Janeczek, Christoph; Mohl, Werner; Gföhler, Margit

2017-06-09

Currently available, pneumatic-based medical devices are operated using closed-loop pulsatile or open continuous systems. Medical devices utilizing gases with a low atomic number in a continuous closed loop stream have not been documented to date. This work presents the construction of a portable helium circulation addressing the need for actuating a novel, pneumatically operated catheter pump. The design of its control system puts emphasis on the performance, safety and low running cost of the catheter pump. Static and dynamic characteristics of individual elements in the circulation are analyzed to ensure a proper operation of the system. The pneumatic circulation maximizes the working range of the drive unit inside the catheter pump while reducing the total size and noise production.Separate flow and pressure controllers position the turbine's working point into the stable region of the pressure creation element. A subsystem for rapid gas evacuation significantly decreases the duration of helium removal after a leak, reaching subatmospheric pressure in the intracorporeal catheter within several milliseconds. The system presented in the study offers an easy control of helium mass flow while ensuring stable behavior of its internal components.

Does helmet CPAP reduce cerebral blood flow and volume by comparison with Infant Flow driver CPAP in preterm neonates?

PubMed

Zaramella, Patrizia; Freato, Federica; Grazzina, Nicoletta; Saraceni, Elisabetta; Vianello, Andrea; Chiandetti, Lino

2006-10-01

We compared neonatal helmet continuous positive airway pressure (CPAP) and the conventional nasal Infant Flow driver (IFD) CPAP in the noninvasive assessment of absolute cerebral blood flow (CBF) and relative cerebral blood volume changes (DeltaCBV) by near-infrared spectroscopy. A randomized crossover study in a tertiary referral NICU. Assessment of CBF and DeltaCBV in 17 very low birth weight infants with respiratory distress (median age 5 days) treated with two CPAP devices at a continuous distending pressure of 4 mbar. Neonates were studied for two consecutive 60-min periods with helmet CPAP and with IFD CPAP. Basal chromophore traces enabled DeltaCBV changes to be calculated. CBF was calculated in milliliters per 100 grams per minute from the saturation rise integral and rate of rise O(2)Hb-HHb. Median (range) CBF with helmet CPAP was 27.37 (9.47-48.20) vs. IFD CBF 34.74 (13.59-60.10)(p=0.049) and DeltaCBV 0.15 (0.09-0.28) with IFD and 0.13 (0.07-0.27) with helmet CPAP (NS). Using helmet and IFD CPAP, the neonates showed no difference in mean physiological parameters (transcutaneous carbon dioxide and oxygen tension, pulse oximetry saturation, heart rate, breathing rate, mean arterial blood pressure, desaturation rate, axillary temperature). Assessing CBF and DeltaCBV measured by near-infrared spectroscopy with two CPAP devices revealed no differences in relative blood volume, but CBF was lower with helmet CPAP. Greater active vasoconstriction and/or passive capillary and/or venous vessel compression seem the most likely reason, due to a positive pressure around the head, neck, and shoulders by comparison with the airway pressure.

Tumour necrosis factor-α/interleukin-10 ratio in patients with obstructive sleep apnoea hypopnoea syndrome.

PubMed

Jiang, H; Cao, H; Wang, P; Liu, W; Cao, F; Chen, J

2015-01-01

To explore the significance of the tumour necrosis factor-α/interleukin-10 ratio and the effect of continuous positive airway pressure in patients with different degrees of obstructive sleep apnoea hypopnoea syndrome severity. This study comprised 135 patients with obstructive sleep apnoea hypopnoea syndrome and 94 control subjects. Tumour necrosis factor-α and tumour necrosis factor-α/interleukin-10 ratio values were significantly higher in the obstructive sleep apnoea hypopnoea syndrome group than in the control group, but interleukin-10 was significantly lower. Tumour necrosis factor-α/interleukin-10 ratio values increased in line with the severity of obstructive sleep apnoea hypopnoea syndrome. In multivariate analysis, the tumour necrosis factor-α/interleukin-10 ratio correlated positively with the apnoea-hypopnoea index and all indices of obstructive sleep apnoea hypopnoea syndrome, except for age, body mass index and neck circumference. After one month of continuous positive airway pressure therapy, levels of tumour necrosis factor-α decreased; interleukin-10 showed no change. The results suggest that inflammation is activated and anti-inflammatory cytokines are decreased in obstructive sleep apnoea hypopnoea syndrome patients. Tumour necrosis factor-α/interleukin-10 ratio may prove useful for severity monitoring and management of obstructive sleep apnoea hypopnoea syndrome patients, and may reduce the need for polysomnography.

Numerical and Experimental Investigation of Stratified Gas-Liquid Two-Phase Flow in Horizontal Circular Pipes

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

Faccini, J.L.H.; Sampaio, P.A.B. de; Su, J.

This paper reports numerical and experimental investigation of stratified gas-liquid two-phase flow in horizontal circular pipes. The Reynolds averaged Navier Stokes equations (RANS) with the k-{omega} model for a fully developed stratified gas-liquid two-phase flow are solved by using the finite element method. A smooth and horizontal interface surface is assumed without considering the interfacial waves. The continuity of the shear stress across the interface is enforced with the continuity of the velocity being automatically satisfied by the variational formulation. For each given interface position and longitudinal pressure gradient, an inner iteration loop runs to solve the nonlinear equations. Themore » Newton-Raphson scheme is used to solve the transcendental equations by an outer iteration to determine the interface position and pressure gradient for a given pair of volumetric flow rates. The interface position in a 51.2 mm ID circular pipe was measured experimentally by the ultrasonic pulse-echo technique. The numerical results were also compared with experimental results in a 21 mm ID circular pipe reported by Masala [1]. The good agreement between the numerical and experimental results indicates that the k-{omega} model can be applied for the numerical simulation of stratified gas-liquid two-phase flow. (authors)« less

Difference between continuous positive airway pressure via mask therapy and incentive spirometry to treat or prevent post-surgical atelectasis.

PubMed

Al-Mutairi, Fouad H; Fallows, Stephen J; Abukhudair, Waleed A; Islam, Baharul B; Morris, Michael M

2012-11-01

To assess the effect of early use of continuous positive airway pressure (CPAP) therapy to treat or prevent acute atelectasis in post-operative cardiac patients particularly smokers and elderly patients. A pilot study suggested enrolling at least 32 participants in each group to be significant. One hundred and eight patients from King Fahd Armed Forces Hospital, Jeddah, Kingdom of Saudi Arabia who met the inclusion criteria participated in this study conducted between March 2010 and March 2011. The participants were divided randomly into 3 groups, incentive spirometry (IS) therapy, and CPAP therapy every 2 (CPAP 2 hrs), or 4 hours (CPAP 4 hrs). Inspiratory capacity (IC) was used to compare the 3 therapy regimes. Simultaneously, respiratory rate (RR), heart rate (HR) and oxygen saturation (SpO2) were measured for all groups. Failure was defined as requiring intubation, bi-level positive airway pressure, or added chest physiotherapy. Thirty-six patients participated in each group (98 male and 10 female, with a mean age of 62+/-9.3 years). The IC increased significantly in the CPAP 2 hrs group when compared with the control group or the CPAP 4hrs group. The SpO2 decreased significantly in the control group and the CPAP 4 hrs groups when compared with the CPAP 2 hrs group. Also, there were no significant differences in RR and HR between all groups. Early use of CPAP via mask therapy for half an hour every 2 hours had better outcomes to re-open collapsed alveoli after cardiac surgery.

ROLE OF SPOUSAL INVOLVEMENT IN CONTINUOUS POSITIVE AIRWAY PRESSURE (CPAP) ADHERENCE IN PATIENTS WITH OBSTRUCTIVE SLEEP APNEA (OSA).

PubMed

Batool-Anwar, Salma; Baldwin, Carol M; Fass, Shira; Quan, Stuart F

2017-05-01

Little is known about the impact of spousal involvement on continuous positive airway pressure (CPAP) adherence. The aim of this study was to determine whether spouse involvement affects adherence with CPAP therapy, and how this association varies with gender. 194 subjects recruited from Apnea Positive Pressure Long Term Efficacy Study (APPLES) completed the Dyadic Adjustment Scale (DAS). The majority of participants were Caucasian (83%), and males (73%), with mean age of 56 years, mean BMI of 31 kg/m 2 . & 62% had severe OSA. The DAS is a validated 32-item self-report instrument measuring dyadic consensus, satisfaction, cohesion, and affectional expression. A high score in the DAS is indicative of a person's adjustment to the marriage. Additionally, questions related to spouse involvement with general health and CPAP use were asked. CPAP use was downloaded from the device and self-report, and compliance was defined as usage ≥ 4 h per night. There were no significant differences in overall marital quality between the compliant and noncompliant subjects. However, level of spousal involvement was associated with increased CPAP adherence at 6 months (p=0.01). After stratifying for gender these results were significant only among males (p=0.03). Three years after completing APPLES, level of spousal involvement was not associated with CPAP compliance even after gender stratification. Spousal involvement is important in determining CPAP compliance in males in the 1 st 6 months after initiation of therapy but is not predictive of longer-term adherence. Involvement of the spouse should be considered an integral part of CPAP initiation procedures. HL068060.

Continuous Positive Airway Pressure Therapy Reduces Right Ventricular Volume in Patients with Obstructive Sleep Apnea: A Cardiovascular Magnetic Resonance Study

PubMed Central

Magalang, Ulysses J.; Richards, Kathryn; McCarthy, Beth; Fathala, Ahmed; Khan, Meena; Parinandi, Narasimham; Raman, Subha V.

2009-01-01

Study Objectives. There are few data on the effects of continuous positive airway pressure (CPAP) therapy on the structural and functional characteristics of the right heart in patients with obstructive sleep apnea (OSA). We sought to leverage the advantages of cardiac magnetic resonance imaging (CMR) and hypothesized that CPAP treatment would improve right ventricular (RV) function in a group of patients with OSA who were free of other comorbid conditions. Methods. Patients with severe (apnea-hypopnea index ≥ 30/h) untreated OSA were prospectively enrolled. CMR included 3-dimensional measurement of biventricular size and function, and rest/stress myocardial perfusion and was performed at baseline and after 3 months of CPAP therapy. Results. Fifteen patients with mild to moderate desaturation were enrolled; 2 could not undergo CMR due to claustrophobia and obesity. There were significant decreases in the Epworth Sleepiness Scale score (p < 0.0001) and RV end-systolic and RV end-diastolic volumes (p < 0.05) with CPAP. There was a trend toward improvement in RV ejection fraction, but the improvement did not reach statistical significance. Other measures such as left ventricular volumes, left ventricular ejection fraction, myocardial perfusion reserve index, and thickness of the interventricular septum and ventricular free wall did not change significantly. Conclusions: This preliminary study found that CPAP treatment decreases RV volumes in patients with severe OSA who are otherwise healthy. CMR offers a novel technique to determine the effects of CPAP on ventricular structure and function in patients with OSA. A randomized controlled study is needed to confirm the results of our study. Citation: Magalang UJ; Richards K; McCarthy B; Fathala A; Khan M; Parinandi N; Raman SV. Continuous positive airway pressure therapy reduces right ventricular volume in patients with obstructive sleep apnea: a cardiovascular magnetic resonance study. J Clin Sleep Med 2009;5(2):110-114. PMID:19968042

Obstructive sleep apnoea/hypopnoea syndrome in adults with Down syndrome.

PubMed

Hill, Elizabeth A

2016-12-01

Adults with Down syndrome are predisposed to obstructive sleep apnoea/hypopnoea syndrome (OSAHS) due to overlap between the Down syndrome phenotype and OSAHS risk factors.The prevalence of OSAHS in adults with Down syndrome is estimated at 35-42%. This is up to ten-times higher than in the general adult population.Symptoms of OSAHS, including behavioural and emotional disturbances as well as standard symptoms such as sleepiness, should be monitored as part of regular health surveillance in adults with Down syndrome.There is evidence that the use of continuous positive airway pressure (CPAP) therapy in adults with Down syndrome and comorbid OSAHS can lead to significant improvements in subjective sleepiness, behaviour and cognitive function, though further large-scale trials are required. To discuss the relationship between the phenotypic features of Down syndrome and the risk factors for obstructive sleep apnoea/hypopnoea syndrome (OSAHS).To examine the prevalence of OSAHS in adults with Down syndrome.To review recent research into the effectiveness of treatment of OSAHS in adults with Down syndrome using continuous positive airway pressure (CPAP) therapy. Obstructive sleep apnoea/hypopnoea syndrome (OSAHS) is characterised by repeated cycles of upper airway obstruction during sleep, leading to diurnal symptoms. Individuals with Down syndrome are predisposed to OSAHS due to overlap between the Down syndrome phenotype and OSAHS risk factors. Recent large studies using subjective and objective measures estimate that OSAHS affects around 40% of adults with Down syndrome, in contrast to 2-4% of the general adult population. The "double-hit" of comorbid Down syndrome and OSAHS may accelerate cognitive decline in adults with Down syndrome. However, with the appropriate care and support, OSAHS can be treated effectively in this group using continuous positive airway pressure (CPAP) therapy, improving daytime function and behaviour. Symptoms of OSAHS should be routinely monitored in this population, with testing and treatment available to all adults with Down syndrome; however, this is not currently commonplace, and health inequalities are evident.

Effect of Continuous Positive Airway Pressure on Stroke Rehabilitation: A Pilot Randomized Sham-Controlled Trial

PubMed Central

Khot, Sandeep P.; Davis, Arielle P.; Crane, Deborah A.; Tanzi, Patricia M.; Li Lue, Denise; Claflin, Edward S.; Becker, Kyra J.; Longstreth, W.T.; Watson, Nathaniel F.; Billings, Martha E.

2016-01-01

Study Objectives: Obstructive sleep apnea (OSA) predicts poor functional outcome after stroke and increases the risk for recurrent stroke. Less is known about continuous positive airway pressure (CPAP) treatment on stroke recovery. Methods: In a pilot randomized, double-blind, sham-controlled trial, adult stroke rehabilitation patients were assigned to auto-titrating or sham CPAP without diagnostic testing for OSA. Change in Functional Independence Measure (FIM), a measure of disability, was assessed between rehabilitation admission and discharge. Results: Over 18 months, 40 patients were enrolled and 10 withdrew from the study: 7 from active and 3 from sham CPAP (p > 0.10). For the remaining 30 patients, median duration of CPAP use was 14 days. Average CPAP use was 3.7 h/night, with at least 4 h nightly use among 15 patients. Adherence was not influenced by treatment assignment or stroke severity. In intention-to-treat analyses (n = 40), the median change in FIM favored active CPAP over sham but did not reach statistical significance (34 versus 26, p = 0.25), except for the cognitive component (6 versus 2.5, p = 0.04). The on-treatment analyses (n = 30) yielded similar results (total FIM: 32 versus 26, p = 0.11; cognitive FIM: 6 versus 2, p = 0.06). Conclusions: A sham-controlled CPAP trial among stroke rehabilitation patients was feasible in terms of recruitment, treatment without diagnostic testing and adequate blinding—though was limited by study retention and CPAP adherence. Despite these limitations, a trend towards a benefit of CPAP on recovery was evident. Tolerance and adherence must be improved before the full benefits of CPAP on recovery can be assessed in larger trials. Citation: Khot SP, Davis AP, Crane DA, Tanzi PM, Li Lue D, Claflin ES, Becker KJ, Longstreth WT, Watson NF, Billings ME. Effect of continuous positive airway pressure on stroke rehabilitation: a pilot randomized sham-controlled trial. J Clin Sleep Med 2016;12(7):1019–1026. PMID:27092703

The Association of Age, Insomnia, and Self-Efficacy with Continuous Positive Airway Pressure Adherence in Black, White, and Hispanic US Veterans

PubMed Central

Wallace, Douglas M.; Shafazand, Shirin; Aloia, Mark S.; Wohlgemuth, William K.

2013-01-01

Study Objectives: Studies of continuous positive airway pressure (CPAP) adherence in multi-ethnic samples are lacking. This study explores previously described factors associated with therapeutic CPAP use in South Florida veterans with obstructive sleep apnea-hypopnea syndrome (OSAHS). Methods: We performed a retrospective, cross-sectional analysis of CPAP adherence comparing white, black, and Hispanic veterans returning to the Miami VA sleep clinic over a 4-month period. Participants had CPAP use download and completed questionnaires on demographics, sleepiness, insomnia, and social cognitive measures related to adherence. Linear regression modeling was used to explore the impact of measured variables and potential interactions with race-ethnicity on mean daily CPAP use. Results: Participants (N = 248) were 94% male with mean age of 59 ± 11 years and included 95 blacks (38%), 91 whites (37%), and 62 Hispanic (25%) veterans. Blacks had less mean daily CPAP use than whites (-1.6 h, p < 0.001) and Hispanics (-1.3 h, p < 0.01). Blacks reported worse sleep onset insomnia symptoms compared to whites. In the final multivariable regression model, black race-ethnicity (p < 0.01), insomnia symptoms (p < 0.001), and self-efficacy (p < 0.001) were significantly associated with mean daily CPAP use. In addition, the black race by age interaction term showed a trend towards significance (p = 0.10). Conclusions: In agreement with recent studies, we found that mean daily CPAP use in blacks was 1 hour less than whites after adjusting for covariates. No CPAP adherence differences were noted between whites and Hispanics. Further investigations exploring sociocultural barriers to regular CPAP use in minority individuals with OSAHS are needed. Citation: Wallace DM; Shafazand S; Aloia MS; Wohlgemuth WK. The association of age, insomnia, and self-efficacy with continuous positive airway pressure adherence in black, white, and Hispanic US veterans. J Clin Sleep Med 2013;9(9):885-895. PMID:23997701

Circulating FABP4 and FABP5 Levels Are Differently Linked to OSA Severity and Treatment

PubMed Central

Català, Raquel; Cabré, Anna; Hernández-Flix, Salvador; Ferré, Raimón; Sangenís, Sandra; Plana, Núria; Texidó, Anna; Masana, Lluís

2013-01-01

Objective: To evaluate circulating adipocyte and epidermal fatty acid-binding protein (FABP4 and FABP5) concentrations in patients with obstructive sleep apnea (OSA), as well as the effects of continuous positive airway pressure (CPAP) treatment. Methods: Our cross-sectional study included 125 patients. After polysomnography, 58 participants met the criteria for CPAP treatment and were included in a closed cohort study of 8 weeks of CPAP treatment. General anthropometric and biochemical data and circulating FABP4 and FABP5 levels were determined in all patients at baseline and after CPAP treatment in those receiving this therapy. Results Circulating FABP4 but not FABP5 levels were higher in patients with OSA (P = 0.003). FABP4 but not FABP5 values were associated with parameters of OSA severity independently of age, gender, adiposity and insulin resistance (P < 0.05). FABP4 but not FABP5 concentrations were determinants of OSA presence (OR: 1.11, P = 0.010) and severity (OR: 1.06, P = 0.020). After CPAP treatment, FABP4 levels decreased in the more severe patients (P = 0.019), while FABP5 levels increased in all patients (P < 0.001). Conclusions FABP4 is directly associated with obstructive sleep apnea severity and did not change with continuous positive airway pressure treatment, while FABP5 was not associated with obstructive sleep apnea severity and increased with continuous positive airway pressure treatment. FABP4 and FABP5 have different associations with obstructive sleep apnea. FABP4 but not FABP5 could be considered a marker of metabolic alterations in obstructive sleep apnea patients. Citation: Català R; Cabré A; Hernández-Flix S; Ferré R; Sangenís S; Plana N; Texidó A; Masana L. Circulating FABP4 and FABP5 levels are differently linked to OSA severity and treatment. SLEEP 2013;36(12):1831-1837. PMID:24293757

Continuous plasma laser. [method and apparatus for producing intense, coherent, monochromatic light from low temperature plasma

NASA Technical Reports Server (NTRS)

Libby, W. F.; Jensen, C. A.; Wood, L. L. (Inventor)

1977-01-01

The apparatus includes a housing for confining a gas at subatmospheric pressure and including a set of reflectors defining an optical cavity. At least one anode and cathode are positioned within the gas. First control means control the voltage applied to the anode and second control means independently control the temperature of the cathode. The pressure of the gas is controlled by a third control means. An intense monochromatic output is achieved by confining the gas in the housing at a controlled pre-determined reduced pressure, independently controlling the temperature of the electron emitting cathode and applying predetermined controlled low voltage to the anode.

Associations of Nasopharyngeal Metabolome and Microbiome with Severity among Infants with Bronchiolitis. A Multiomic Analysis.

PubMed

Stewart, Christopher J; Mansbach, Jonathan M; Wong, Matthew C; Ajami, Nadim J; Petrosino, Joseph F; Camargo, Carlos A; Hasegawa, Kohei

2017-10-01

Bronchiolitis is the most common lower respiratory infection in infants; however, it remains unclear which infants with bronchiolitis will develop severe illness. In addition, although emerging evidence indicates associations of the upper-airway microbiome with bronchiolitis severity, little is known about the mechanisms linking airway microbes and host response to disease severity. To determine the relations among the nasopharyngeal airway metabolome profiles, microbiome profiles, and severity in infants with bronchiolitis. We conducted a multicenter prospective cohort study of infants (age <1 yr) hospitalized with bronchiolitis. By applying metabolomic and metagenomic (16S ribosomal RNA gene and whole-genome shotgun sequencing) approaches to 144 nasopharyngeal airway samples collected within 24 hours of hospitalization, we determined metabolome and microbiome profiles and their association with higher severity, defined by the use of positive pressure ventilation (i.e., continuous positive airway pressure and/or intubation). Nasopharyngeal airway metabolome profiles significantly differed by bronchiolitis severity (P < 0.001). Among 254 metabolites identified, a panel of 25 metabolites showed high sensitivity (84%) and specificity (86%) in predicting the use of positive pressure ventilation. The intensity of these metabolites was correlated with relative abundance of Streptococcus pneumoniae. In the pathway analysis, sphingolipid metabolism was the most significantly enriched subpathway in infants with positive pressure ventilation use compared with those without (P < 0.001). Enrichment of sphingolipid metabolites was positively correlated with the relative abundance of S. pneumoniae. Although further validation is needed, our multiomic analyses demonstrate the potential of metabolomics to predict bronchiolitis severity and better understand microbe-host interaction.

Intra-gastric pressures in neonates receiving bubble CPAP.

PubMed

Tyagi, Prashant; Gupta, Neeraj; Jain, Akanksha; Upadhyay, Pramod; Puliyel, Jacob

2015-02-01

To study intra-gastric pressures in neonates receiving bubble continuous positive airway pressure (BCPAP) by nasopharyngeal prong. Twenty seven neonates were recruited for the study. BCPAP pressure of 6 cm water was used in all the neonates. A pressure sensor attached to orogastric tube, measured the intra-gastric pressure prior to starting BCPAP and again between 30 and 90 min of BCPAP. The clinical variables like Downe's score, oxygen saturation, venous blood gas pH, pCO(2) and abdominal girth were recorded alongside with pressure readings. BCPAP resulted in improvement (p < 0.05) in parameters of respiratory distress such as Downe's score (DS), oxygen saturation (SpO(2)) and venous blood gas parameters (pH, pCO(2)). There was no statistical significant increase in intra-gastric pressures (p = 0.834). There were no gastrointestinal complications; abdominal distention, necrotising enterocolitis or gastric perforation during the study. Nasopharyngeal BCPAP at 6 cm of water pressure is an effective modality of treating babies with respiratory distress and the present study shows that it is not associated with a significant rise in intra-gastric pressures.

Monitoring Progress and Adherence with Positive Airway Pressure Therapy for Obstructive Sleep Apnea: The Roles of Telemedicine and Mobile Health Applications.

PubMed

Hwang, Dennis

2016-06-01

Technology is changing the way health care is delivered and how patients are approaching their own health. Given the challenge within sleep medicine of optimizing adherence to continuous positive airway pressure (CPAP) therapy in patients with obstructive sleep apnea (OSA), implementation of telemedicine-based mechanisms is a critical component toward developing a comprehensive and cost-effective solution for OSA management. Key elements include the use of electronic messaging, remote monitoring, automated care mechanisms, and patient self-management platforms. Current practical sleep-related telemedicine platforms include Web-based educational programs, automated CPAP follow-up platforms that promote self-management, and peer-based patient-driven Internet support forums. Copyright © 2016 Elsevier Inc. All rights reserved.

System Design Verification for Closed Loop Control of Oxygenation With Concentrator Integration.

PubMed

Gangidine, Matthew M; Blakeman, Thomas C; Branson, Richard D; Johannigman, Jay A

2016-05-01

Addition of an oxygen concentrator into a control loop furthers previous work in autonomous control of oxygenation. Software integrates concentrator and ventilator function from a single control point, ensuring maximum efficiency by placing a pulse of oxygen at the beginning of the breath. We sought to verify this system. In a test lung, fraction of inspired oxygen (FIO2) levels and additional data were monitored. Tests were run across a range of clinically relevant ventilator settings in volume control mode, for both continuous flow and pulse dose flow oxygenation. Results showed the oxygen concentrator could maintain maximum pulse output (192 mL) up to 16 breaths per minute. Functionality was verified across ranges of tidal volumes and respiratory rates, with and without positive end-expiratory pressure, in continuous flow and pulse dose modes. For a representative test at respiratory rate 16 breaths per minute, tidal volume 550 mL, without positive end-expiratory pressure, pulse dose oxygenation delivered peak FIO2 of 76.83 ± 1.41%, and continuous flow 47.81 ± 0.08%; pulse dose flow provided a higher FIO2 at all tested setting combinations compared to continuous flow (p < 0.001). These tests verify a system that provides closed loop control of oxygenation while integrating time-coordinated pulse-doses from an oxygen concentrator. This allows the most efficient use of resources in austere environments. Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.

Local Pressure Application Effects on Discomfort, Temperature, and Limb Oxygenation.

PubMed

Games, Kenneth E; Lakin, Joni M; Quindry, John C; Weimar, Wendi H; Sefton, JoEllen M

2016-08-01

Despite significant investment into the development and improvement of military helicopter seat systems, military aviators continue to report seat system related pain and discomfort during prolonged missions. Using a factorial repeated measures design, 15 healthy subjects completed the study, in which focal pressure was applied to two locations on the sitting surfaces of the body (ischial tuberosity and middle of the posterior thigh). Pressure was applied using a purpose-built pressure application system allowing subjects to sit in a position mimicking the sitting position in the UH-60 Black Hawk helicopter. The researchers measured pain using the Category Partitioning Scale and McGill Pain Questionnaire and vascular function using dynamic infrared thermography in the lower leg and pulse oximetry at the great toe. Data were collected before and during a 10-min application of focal pressure applied to either the ischial tuberosity or middle of the posterior thigh and at two different pressure magnitudes (36 or 44 kPa). We found that during a 10-min pressure application, superficial skin temperature increased by 0.61°C, suggesting a decreased venous return during pressure application. We found that lower extremity blood oxygenation remained unchanged during pressure application. Subjects' reported pain increased during pressure application and was greater with 44 kPa of application compared to 36 kPa. These results support the hypothesis that locally high pressure creates symptoms of discomfort and paresthesia. Research examining the effects of local pressure application on physiological and neurological function is needed. Games KE, Lakin JM, Quindry JC, Weimar WH, Sefton JM. Local pressure application effects on discomfort, temperature, and limb oxygenation. Aerosp Med Hum Perform. 2016; 87(8):697-703.

Design and Validation of In-Source Atmospheric Pressure Photoionization Hydrogen/Deuterium Exchange Mass Spectrometry with Continuous Feeding of D2O

NASA Astrophysics Data System (ADS)

Acter, Thamina; Lee, Seulgidaun; Cho, Eunji; Jung, Maeng-Joon; Kim, Sunghwan

2018-01-01

In this study, continuous in-source hydrogen/deuterium exchange (HDX) atmospheric pressure photoionization (APPI) mass spectrometry (MS) with continuous feeding of D2O was developed and validated. D2O was continuously fed using a capillary line placed on the center of a metal plate positioned between the UV lamp and nebulizer. The proposed system overcomes the limitations of previously reported APPI HDX-MS approaches where deuterated solvents were premixed with sample solutions before ionization. This is particularly important for APPI because solvent composition can greatly influence ionization efficiency as well as the solubility of analytes. The experimental parameters for APPI HDX-MS with continuous feeding of D2O were optimized, and the optimized conditions were applied for the analysis of nitrogen-, oxygen-, and sulfur-containing compounds. The developed method was also applied for the analysis of the polar fraction of a petroleum sample. Thus, the data presented in this study clearly show that the proposed HDX approach can serve as an effective analytical tool for the structural analysis of complex mixtures. [Figure not available: see fulltext.

Oscillatory patterns in sympathetic neural discharge and cardiovascular variables during orthostatic stimulus

NASA Technical Reports Server (NTRS)

Furlan, R.; Porta, A.; Costa, F.; Tank, J.; Baker, L.; Schiavi, R.; Robertson, D.; Malliani, A.; Mosqueda-Garcia, R.

2000-01-01

BACKGROUND: We tested the hypothesis that a common oscillatory pattern might characterize the rhythmic discharge of muscle sympathetic nerve activity (MSNA) and the spontaneous variability of heart rate and systolic arterial pressure (SAP) during a physiological increase of sympathetic activity induced by the head-up tilt maneuver. METHODS AND RESULTS: Ten healthy subjects underwent continuous recordings of ECG, intra-arterial pressure, respiratory activity, central venous pressure, and MSNA, both in the recumbent position and during 75 degrees head-up tilt. Venous samplings for catecholamine assessment were obtained at rest and during the fifth minute of tilt. Spectrum and cross-spectrum analyses of R-R interval, SAP, and MSNA variabilities and of respiratory activity provided the low (LF, 0.1 Hz) and high frequency (HF, 0.27 Hz) rhythmic components of each signal and assessed their linear relationships. Compared with the recumbent position, tilt reduced central venous pressure, but blood pressure was unchanged. Heart rate, MSNA, and plasma epinephrine and norepinephrine levels increased, suggesting a marked enhancement of overall sympathetic activity. During tilt, LF(MSNA) increased compared with the level in the supine position; this mirrored similar changes observed in the LF components of R-R interval and SAP variabilities. The increase of LF(MSNA) was proportional to the amount of the sympathetic discharge. The coupling between LF components of MSNA and R-R interval and SAP variabilities was enhanced during tilt compared with rest. CONCLUSIONS: During the sympathetic activation induced by tilt, a similar oscillatory pattern based on an increased LF rhythmicity characterized the spontaneous variability of neural sympathetic discharge, R-R interval, and arterial pressure.

Physiology of prolonged bed rest

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.

1988-01-01

Bed rest has been a normal procedure used by physicians for centuries in the treatment of injury and disease. Exposure of patients to prolonged bed rest in the horizontal position induces adaptive deconditioning responses. While deconditioning responses are appropriate for patients or test subjects in the horizontal position, they usually result in adverse physiological responses (fainting, muscular weakness) when the patient assume the upright posture. These deconditioning responses result from reduction in hydrostatic pressure within the cardiovascular system, virtual elimination of longitudinal pressure on the long bones, some decrease in total body metabolism, changes in diet, and perhaps psychological impact from the different environment. Almost every system in the body is affected. An early stimulus is the cephalic shift of fluid from the legs which increases atrial pressure and induces compensatory responses for fluid and electrolyte redistribution. Without countermeasures, deterioration in strength and muscle function occurs within 1 wk while increased calcium loss may continue for months. Research should also focus on drug and carbohydrate metabolism.

Influence of dental occlusion on postural control and plantar pressure distribution.

PubMed

Scharnweber, Benjamin; Adjami, Frederic; Schuster, Gabriele; Kopp, Stefan; Natrup, Jörg; Erbe, Christina; Ohlendorf, Daniela

2017-11-01

The number of studies investigating correlations between the temporomandibular system and body posture, postural control or plantar pressure distribution is continuously increasing. If a connection can be found, it is often of minor influence or for only a single parameter. However, small subject groups are critical. This study was conducted to define correlations between dental parameters, postural control and plantar pressure distribution in healthy males. In this study, 87 male subjects with an average age of 25.23 ± 3.5 years (ranging from 18 to 35 years) were examined. Dental casts of the subjects were analyzed. Postural control and plantar pressure distribution were recorded by a force platform. Possible orthodontic and orthopedic factors of influence were determined by either an anamnesis or a questionnaire. All tests performed were randomized and repeated three times each for intercuspal position (ICP) and blocked occlusion (BO). For a statistical analysis of the results, non-parametric tests (Wilcoxon-Matched-Pairs-Test, Kruskall-Wallis-Test) were used. A revision of the results via Bonferroni-Holm correction was considered. ICP increases body sway in the frontal (p ≤ 0.01) and sagittal planes (p ≤ 0.03) compared to BO, whereas all other 29 correlations were independent of the occlusion position. For both of the ICP or BO cases, Angle-class, midline-displacement, crossbite, or orthodontic therapy were found to have no influence on postural control or plantar pressure distribution (p > 0.05). However, the contact time of the left foot decreased (p ≤ 0.001) while detecting the plantar pressure distribution in each position. Persistent dental parameters have no effect on postural sway. In addition, postural control and plantar pressure distribution have been found to be independent postural criteria.

Evidence Regarding the Use of Bubble Continuous Positive Airway Pressure in the Extremely Low Birth-Weight Infant: Benefits, Challenges, and Implications for Nursing Practice.

PubMed

Alessi, Samantha

2018-06-01

Gentle ventilation with optimal oxygenation is integral to prevention of chronic lung disease in the extremely low birth-weight (ELBW) infant. Various types of noninvasive ventilation are used in neonatal intensive care units worldwide. Bubble continuous positive airway pressure (BCPAP) has been in use in newborn intensive care since 1975. To synthesize the current evidence on the use of BCPAP in the ELBW infant and its relationship to outcomes, particularly morbidity and mortality. A literature review was completed using PubMed, EMBASE, CINAHL, and Cochrane with a focus on BCPAP use in the ELBW population. No study found was exclusive to the ELBW population. All studies ranged from ELBW to full-term neonates. Studies supported the use of BCPAP in the ELBW, demonstrating decreased incidence of chronic lung disease and barotrauma through the use of oscillation and permissive hypercapnia. Literature supports the use of nasal bubble CPAP in the ELBW population. Barriers such as septal erosion, pneumothorax, inconsistent pressures, and air in the abdomen were identified and management recommendations were provided. Studies are needed comparing outcomes of nasal bubble CPAP use with other forms of CPAP in the ELBW infant, comparison of prongs to mask for nasal bubble CPAP, and comparing interventions to recommend optimal care bundles to prevent nasal septum injuries.

The patient inflating valve in anaesthesia and resuscitation breathing systems.

PubMed

Fenton, P M; Bell, G

2013-03-01

Patient inflating valves combined with self-inflating bags are known to all anaesthetists as resuscitation devices and are familiar as components of draw-over anaesthesia systems. Their variants are also commonplace in transfer and home ventilators. However, the many variations in structure and function have led to difficulties in their optimal use, definition and classification. After reviewing the relevant literature, we defined a patient inflating valve as a one-way valve that closes an exit port to enable lung inflation, also permitting exhalation and spontaneous breathing, the actions being automatic. We present a new classification based on the mechanism of valve opening/closure; namely elastic recoil of a flexible flap/diaphragm, sliding spindle opened by a spring/magnet or a hollow balloon collapsed by external pressure. The evolution of these valves has been driven by the difficulties documented in critical incidents, which we have used along with information from modern International Organization for Standardization standards to identify 13 ideal properties, the top six of which are non-jamming, automatic, no bypass effect, no rebreathing or air entry at patient end, low resistance, robust and easy to service. The Ambu and the Laerdal valves have remained popular due to their simplicity and reliability. Two new alternatives, the Fenton and Diamedica valves, offer the benefits of location away from the patient while retaining a small functional dead space. They also offer the potential for greater use of hybrid continuous flow/draw-over systems that can operate close to atmospheric pressure. The reliable application of positive end-expiratory pressure/continuous positive airway pressure remains a challenge.

[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.

Apparatus and process to eliminate diffusional limitations in a membrane biological reactor by pressure cycling

DOEpatents

Efthymiou, George S.; Shuler, Michael L.

1989-08-29

An improved multilayer continuous biological membrane reactor and a process to eliminate diffusional limitations in membrane reactors in achieved by causing a convective flux of nutrient to move into and out of an immobilized biocatalyst cell layer. In a pressure cycled mode, by increasing and decreasing the pressure in the respective layers, the differential pressure between the gaseous layer and the nutrient layer is alternately changed from positive to negative. The intermittent change in pressure differential accelerates the transfer of nutrient from the nutrient layers to the biocatalyst cell layer, the transfer of product from the cell layer to the nutrient layer and the transfer of byproduct gas from the cell layer to the gaseous layer. Such intermittent cycling substantially eliminates mass transfer gradients in diffusion inhibited systems and greatly increases product yield and throughput in both inhibited and noninhibited systems.

Fifty Years of Research in ARDS. Respiratory Mechanics in Acute Respiratory Distress Syndrome.

PubMed

Henderson, William R; Chen, Lu; Amato, Marcelo B P; Brochard, Laurent J

2017-10-01

Acute respiratory distress syndrome is a multifactorial lung injury that continues to be associated with high levels of morbidity and mortality. Mechanical ventilation, although lifesaving, is associated with new iatrogenic injury. Current best practice involves the use of small Vt, low plateau and driving pressures, and high levels of positive end-expiratory pressure. Collectively, these interventions are termed "lung-protective ventilation." Recent investigations suggest that individualized measurements of pulmonary mechanical variables rather than population-based ventilation prescriptions may be used to set the ventilator with the potential to improve outcomes beyond those achieved with standard lung protective ventilation. This review outlines the measurement and application of clinically applicable pulmonary mechanical concepts, such as plateau pressures, driving pressure, transpulmonary pressures, stress index, and measurement of strain. In addition, the concept of the "baby lung" and the utility of dynamic in addition to static measures of pulmonary mechanical variables are discussed.

Elements of an improved model of debris‐flow motion

USGS Publications Warehouse

Iverson, Richard M.

2009-01-01

A new depth‐averaged model of debris‐flow motion describes simultaneous evolution of flow velocity and depth, solid and fluid volume fractions, and pore‐fluid pressure. Non‐hydrostatic pore‐fluid pressure is produced by dilatancy, a state‐dependent property that links the depth‐averaged shear rate and volumetric strain rate of the granular phase. Pore‐pressure changes caused by shearing allow the model to exhibit rate‐dependent flow resistance, despite the fact that the basal shear traction involves only rate‐independent Coulomb friction. An analytical solution of simplified model equations shows that the onset of downslope motion can be accelerated or retarded by pore‐pressure change, contingent on whether dilatancy is positive or negative. A different analytical solution shows that such effects will likely be muted if downslope motion continues long enough, because dilatancy then evolves toward zero, and volume fractions and pore pressure concurrently evolve toward steady states.

Elements of an improved model of debris-flow motion

USGS Publications Warehouse

Iverson, R.M.

2009-01-01

A new depth-averaged model of debris-flow motion describes simultaneous evolution of flow velocity and depth, solid and fluid volume fractions, and pore-fluid pressure. Non-hydrostatic pore-fluid pressure is produced by dilatancy, a state-dependent property that links the depth-averaged shear rate and volumetric strain rate of the granular phase. Pore-pressure changes caused by shearing allow the model to exhibit rate-dependent flow resistance, despite the fact that the basal shear traction involves only rate-independent Coulomb friction. An analytical solution of simplified model equations shows that the onset of downslope motion can be accelerated or retarded by pore-pressure change, contingent on whether dilatancy is positive or negative. A different analytical solution shows that such effects will likely be muted if downslope motion continues long enough, because dilatancy then evolves toward zero, and volume fractions and pore pressure concurrently evolve toward steady states. ?? 2009 American Institute of Physics.

[Single nasal prong versus infant flow driver in very low birth weight infants: clinical efficacy of two modes of nasal continuous positive airway pressure (CPAP)].

PubMed

Gulczyńska, Ewa; Zjawiona, Agnieszka; Sobolewska, Barbara; Gadzinowski, Janusz

2002-01-01

The authors compared efficacy of two different NCPAP techniques in VLBW newborn with respiratory insufficiency. Among the patients with IFD support the higher weaning rate and the lower supplemental oxygen requirement as well as secondary infections incidents was observed.

Positive Behavior Supports: A Study of Implementation at the Intermediate School Level

ERIC Educational Resources Information Center

Hasson, Robert C., Jr.

2011-01-01

Public schools are faced with the ever-increasing pressure of maintaining a safe learning environment while continuously improving student performance. Also, there has been a growing concern among administrators and teachers for implementing an effective discipline plan that will keep students in class and engaged in learning as much as possible.…

Severe obstructive sleep apnoea syndrome in an adult patient with Laron syndrome.

PubMed

Dagan, Y; Abadi, J; Lifschitz, A; Laron, Z

2001-08-01

A 68 year old patient with Laron syndrome (primary growth hormone (GH) resistance-insensitivity due to a molecular defect of the GH receptor) and severe obstructive sleep apnoea syndrome is described. Treatment with continuous positive air pressure therapy resulted in improved nocturnal sleep, daytime alertness and cognitive functions. Copyright 2001 Harcourt Publishers Ltd.

Sleep Apnea - Multiple Languages

MedlinePlus

... Cantonese dialect) (繁體中文) French (français) Hindi (हिन्दी) Japanese (日本語) Korean (한국어) Portuguese (português) Russian (Русский) Somali ( ... हिन्दी (Hindi) Bilingual PDF Health Information Translations Japanese (日本語) Expand Section CPAP (Continuous Positive Airway Pressure) - ...

Total heart replacement using dual intracorporeal continuous-flow pumps in a chronic bovine model: a feasibility study.

PubMed

Frazier, O H; Tuzun, Egemen; Cohn, William E; Conger, Jeffrey L; Kadipasaoglu, Kamuran A

2006-01-01

Continuous-flow pumps are small, simple, and respond physiologically to input variations, making them potentially ideal for total heart replacement. However, the physiological effects of complete pulseless flow during long-term circulatory support without a cardiac interface or with complete cardiac exclusion have not been well studied. We evaluated the feasibility of dual continuous-flow pumps as a total artificial heart (TAH) in a chronic bovine model. Both ventricles of a 6-month-old Corriente crossbred calf were excised and sewing rings attached to the reinforced atrioventricular junctions. The inlet portions of 2 Jarvik 2000 pumps were positioned through their respective sewing rings at the mid-atrial level and the pulseless atrial reservoir connected end-to-end to the pulmonary artery and aorta. Pulseless systemic and pulmonary circulations were thereby achieved. Volume status was controlled, and systemic and pulmonary resistance were managed pharmacologically to keep mean arterial pressures at 100+/-10 mmHg (systemic) and 20+/-5 mmHg (pulmonary) and both left and right atrial pressures at 15+/-5 mmHg. The left pump speed was maintained at 14,000 rpm and its output autoregulated in response to variations in right pump flow, systemic and pulmonary pressures, fluid status, and activity level. Hemodynamics, end-organ function, and neurohormonal status remained normal. These results suggest the feasibility of using dual continuous-flow pumps as a TAH.

An Autonomous, Low Cost Platform for Seafloor Geodetic Observations

NASA Astrophysics Data System (ADS)

Ericksen, T.; Foster, J. H.; Bingham, B. S.; Oshiro, J.

2015-12-01

The Pacific GPS Facility and the Field Robotics Laboratory at the University of Hawaii have developed an approach to significantly reduce the costs of accurately measuring short-term vertical motions of the seafloor and maintaining a continuous long-term record of seafloor pressure. Traditional ship-based methods of acquiring these measurements are often prohibitively expensive. Our goal has been to reduce the primary barrier preventing us from acquiring the observations we need to understand geodetic processes, and the hazards they present, at subduction zones, submarine volcanoes, and subsea landslides. To this end, we have designed a payload package for the University of Hawaii Wave Glider which incorporates an acoustic telemetry package, a dual frequency geodetic-grade Global Positioning System (GPS) receiver, meteorological sensors, processing computer, and cellular communications. The Wave Glider is able to interrogate high accuracy pressure sensors on the seafloor to maintain a near-continuous stream of ocean bottom pressure and temperature data. The Wave Glider also functions as an integral part of the seafloor geodetic observing system, recording accurate sea surface elevations and barometric pressure; direct measurements of two of the primary sources of seafloor pressure change. The seafloor geodetic monument seats a sensor capable of recording pressure, temperature, and sound velocity for a deployment duration of over 5 years with an acoustic modem for communications, and an integral acoustic release for recovery and replacement of batteries. The design of the geodetic monument allows for precise repositioning of the sensor to extend the pressure record beyond a single 5+ year deployment, and includes the capability to install a mobile pressure recorder for calibration of the linear drift of the continuous pressure sensor. We will present the results of our field tests and an assessment of our ability to determine cm-scale vertical seafloor motions by integrating our seafloor pressure measurements with the independent Wave Glider measurements of sea surface pressure and sea surface height. An overall summary of the performance and costs of making seafloor geodetic measurement with this system will be provided.

Brain tissue partial pressure of oxygen predicts the outcome of severe traumatic brain injury under mild hypothermia treatment.

PubMed

Sun, Hongtao; Zheng, Maohua; Wang, Yanmin; Diao, Yunfeng; Zhao, Wanyong; Wei, Zhengjun

2016-01-01

The aim of this study was to investigate the clinical significance and changes of brain tissue partial pressure of oxygen (PbtO2) in the course of mild hypothermia treatment (MHT) for treating severe traumatic brain injury (sTBI). There were 68 cases with sTBI undergoing MHT. PbtO2, intracranial pressure (ICP), jugular venous oxygen saturation (SjvO2), and cerebral perfusion pressure (CPP) were continuously monitored, and clinical outcomes were evaluated using the Glasgow Outcome Scale score. Of 68 patients with sTBI, PbtO2, SjvO2, and CPP were obviously increased, but decreased ICP level was observed throughout the MHT. PbtO2 and ICP were negatively linearly correlated, while there was a positive linear correlation between PbtO2 and SjvO2. Monitoring CPP and SjvO2 was performed under normal circumstances, and a large proportion of patients were detected with low PbtO2. Decreased PbtO2 was also found after MHT. Continuous PbtO2 monitoring could be introduced to evaluate the condition of regional cerebral oxygen metabolism, thereby guiding the clinical treatment and predicting the outcome.

An Autonomous, Low Cost Platform for Seafloor Geodetic Observations

NASA Astrophysics Data System (ADS)

Ericksen, T.; Foster, J. H.; Bingham, B. S.

2013-12-01

The high cost of acquiring geodetic data from the sea floor has limited the observations available to help us understand and model the behavior of seafloor geodetic processes. To address this problem, the Pacific GPS Facility at the University of Hawaii is developing a cost effective approach for accurately measuring short-term vertical motions of the seafloor and maintaining a continuous long-term record of seafloor pressure without the requirement for costly ship time. There is a recognized need to vastly increase our underwater geodetic observing capacity. Most of the largest recorded earthquakes and most devastating tsunamis are generated at subduction zones underwater. Similarly, many volcanoes are partly (e.g. Santorini) or completely (e.g. Loihi) submerged, and are not well observed and understood. Furthermore, landslide features ring many ocean basins, and huge debris deposits surround many volcanic oceanic islands. Our approach will lower the cost of collecting sea-floor geodetic data, reducing the barriers preventing us from acquiring the information we need to observe and understand these types of structures and provide a direct societal benefit in improving hazard assessment. The capability is being developed by equipping one of the University of Hawaii Wave Gliders with an integrated acoustic telemetry package, a dual frequency geodetic-grade Global Positioning System (GPS) receiver, processing unit, and cellular communications. The Wave Glider will interrogate high accuracy pressure sensors on the sea floor to maintain a near-continuous stream of pressure and temperature data, but seafloor pressure data includes contribution from a variety of sources and on its own may not provide the accuracy required for geodetic investigations. Independent measurements of sea surface pressure and sea surface height can be used to remove these contributions from the observed sea floor pressure timeseries. We will integrate our seafloor pressure measurements with air pressure data, and precise vertical measurements of the sea surface from kinematic positioning of the Wave Glider over the bottom sensor, to determine cm-scale vertical seafloor motions. The seafloor package will consist of a simple tripod frame that seats the pressure sensor unit, and includes an attachment onto which an ROV can install a mobile pressure recorder (MPR) should ship and ROV time be available. Two visits with an MPR would allow calibration of the linear drift of the continuous sensor, further enhancing the value of the timeseries. The pressure sensor is recoverable and serviceable and using the MPR calibration will enable the seafloor monument to be re-occupied to extend the pressure record beyond a single 5+ year deployment. We are currently focused on retrieving high accuracy vertical sea floor motions, but, importantly, we have chosen a development approach that provides a simple upgrade path for incorporating the Wave Glider GPS-Acoustic (GPS/A) measurement system under development at SIO. With this upgrade, Wave Gliders could also acquire accurate horizontal motions of the sea floor sensors, and provide a cost-effective way of performing full, 3-dimensional, surveys of sea-floor motions.

Role of non-invasive ventilation (NIV) in the perioperative period.

PubMed

Jaber, Samir; Michelet, Pierre; Chanques, Gerald

2010-06-01

Anaesthesia, postoperative pain and surgery (more so if the site of the surgery approaches the diaphragm) will induce respiratory modifications: hypoxaemia, pulmonary volume decrease and atelectasis associated to a restrictive syndrome and a diaphragm dysfunction. These modifications of the respiratory function occur early after surgery and may induce acute respiratory failure (ARF). Maintenance of adequate oxygenation in the postoperative period is of major importance, especially when pulmonary complications such as ARF occur. Non-invasive ventilation (NIV) refers to techniques allowing respiratory support without the need of endotracheal intubation. Two types of NIV are commonly used: noninvasive continuous positive airway pressure (CPAP) and noninvasive positive pressure ventilation (NPPV) which delivers two levels of positive pressure (pressure support ventilation + positive end-expiratory pressure). NIV may be an important tool to prevent (prophylactic treatment) or to treat ARF avoiding intubation (curative treatment). The aims of NIV are: (1) to partially compensate for the affected respiratory function by reducing the work of breathing, (2) to improve alveolar recruitment with better gas exchange (oxygenation and ventilation) and (3) to reduce left ventricular after load increasing cardiac output and improving haemodynamics. Evidence suggests that NIV, as a prophylactic or curative treatment, has been proven to be an effective strategy to reduce intubation rates, nosocomial infections, intensive care unit and hospital lengths of stay, morbidity and mortality in postoperative patients. However, before initiating NIV, any surgical complication must be treated. The aims of this article are (1) to describe the rationale behind the application of NIV, (2) to report indications (including induction of anaesthesia) and contraindications and (3) to offer some algorithms for safe usage of NIV in high-risk surgery patients.

Improving Heart rate variability in sleep apnea patients: differences in treatment with auto-titrating positive airway pressure (APAP) versus conventional CPAP.

PubMed

Karasulu, Levent; Epöztürk, Pinar Ozkan; Sökücü, Sinem Nedime; Dalar, Levent; Altin, Sedat

2010-08-01

The effect of positive airway pressure treatments in different modalities on the cardiovascular consequences of the disease in sleep apnea patients is still unclear. We aimed to compare auto-titrating positive airway pressure (APAP) and conventional continuous positive airway pressure (CPAP) in terms of improving heart rate variability (HRV) in obstructive sleep apnea patients. This was a prospective study done in a tertiary research hospital. All patients underwent a manual CPAP titration procedure to determine the optimal pressure that abolishes abnormal respiratory events. Then patients underwent two treatment nights, one under APAP mode and one under conventional CPAP mode with a 1-week interval. Forty newly diagnosed obstructive sleep apnea patients were enrolled in the study. We compared heart rate variability analysis parameters between the APAP night and the CPAP night. This final analysis included the data of 28 patients (M/F: 22/6; mean age = 46 +/- 10 years). Sleep characteristics were comparable between the two treatment nights, whereas all-night time domains of HRV analysis such as HF, nuLF, and LF/HF were different between APAP and CPAP nights (2.93 +/- 0.31 vs. 3.01 +/- 0.31; P = 0.041; 0.75 +/- 0.13 vs. 0.71 +/- 0.14; P = 0.027; and 4.37 +/- 3.24 vs. 3.56 +/- 2.07; P = 0.023, respectively). HRV analysis for individual sleep stages showed that Stage 2 LF, nuLF, nuHF, LF/HF parameters entirely improved under CPAP treatment whereas APAP treatment resulted in nonsignificant changes. These results suggest that despite comparable improvement in abnormal respiratory events with APAP or CPAP treatments, CPAP may be superior to APAP in terms of correcting cardiovascular alterations in sleep apnea patients.

Effect of Continuous Positive Airway Pressure on Airway Reactivity in Asthma. A Randomized, Sham-controlled Clinical Trial

PubMed Central

Sugar, Elizabeth A.; Brown, Robert H.; Drye, Lea T.; Irvin, Charles G.; Schwartz, Alan R.; Tepper, Robert S.; Wise, Robert A.; Yasin, Razan Z.; Busk, Michael F.

2016-01-01

Rationale: Studies have demonstrated that application of stress suppresses airway smooth muscle contractility. In animal models of asthma, continuous positive airway pressure (CPAP) reduced airway reactivity. Short-term studies of CPAP in patients with asthma showed reductions in airway reactivity. Objectives: To evaluate whether nocturnal CPAP decreased the provocative concentration of methacholine to reduce FEV1 by 20% (PC20). Methods: One hundred ninety-four individuals with asthma were randomized (1:1:1) to use CPAP with warmed, filtered, humidified air at night at pressures either less than 1 cm H2O (sham) or at 5 cm H2O or 10 cm H2O. The primary outcome was change in PC20 after 12 weeks. Measurements and Main Results: Adherence to CPAP was low in all groups. Regardless, all groups had a significant improvement in PC20, with 12 weeks/baseline PC20 ratios of 2.12, 1.73, and 1.78 for the sham, 5 cm H2O, and 10 cm H2O groups, respectively, and no significant differences between the active and sham groups. Changes in FEV1 and exhaled nitric oxide were minimal in all groups. The sham group had larger improvements in most patient-reported outcomes measuring asthma symptoms and quality of life, as well as sinus symptoms, than the 5 cm H2O group. The 10 cm H2O group showed similar but less consistent improvements in scores, which were not different from improvements in the sham group. Conclusions: Adherence to nocturnal CPAP was low. There was no evidence to support positive pressure as being effective for reducing airway reactivity in people with well-controlled asthma. Regardless, airway reactivity was improved in all groups, which may represent an effect of participating in a study and/or an effect of warm, humid, filtered air on airway reactivity. Clinical trial registered with www.clinicaltrials.gov (NCT01629823). PMID:27398992

Effects of a continuous lateral turning device on pressure relief.

PubMed

Do, Nam Ho; Kim, Deog Young; Kim, Jung-Hoon; Choi, Jong Hyun; Joo, So Young; Kang, Na Kyung; Baek, Yoon Su

2016-01-01

[Purpose] The purpose of this study was to examine the pressure-relieving effects of a continuous lateral turning device on common pressure ulcer sites. [Subjects] Twenty-four healthy adults participated. [Methods] The design of our continuous lateral turning device was motivated by the need for an adequate pressure-relieving device for immobile and/or elderly people. The procedure of manual repositioning is embodied in our continuous lateral turning device. The interface pressure and time were measured, and comfort grade was evaluated during sessions of continuous lateral turning at 0°, 15°, 30°, and 45°. We quantified the pressure-relieving effect using peak pressure, mean pressure, and pressure time integration. [Results] Participants demonstrated pressure time integration values below the pressure-time threshold at 15°, 30°, and 45° at all the common pressure ulcer sites. Moreover, the most effective angles for pressure relief at the common pressure ulcer sites were 30° at the occiput, 15° at the left scapula, 45° at the right scapula, 45° at the sacrum, 15° at the right heel, and 30° at the left heel. However, angles greater than 30° induced discomfort. [Conclusion] Continuous lateral turning with our specially designed device effectively relieved the pressure of targeted sites. Moreover, the suggested angles of continuous lateral turning can be used to relieve pressure at targeted sites.

Evaluation of the Boussignac Cardiac arrest device (B-card) during cardiopulmonary resuscitation in an animal model.

PubMed

Moore, Johanna C; Lamhaut, Lionel; Hutin, Alice; Dodd, Kenneth W; Robinson, Aaron E; Lick, Michael C; Salverda, Bayert J; Hinke, Mason B; Labarere, José; Debaty, Guillaume; Segal, Nicolas

2017-10-01

The purpose of this study was to examine continuous oxygen insufflation (COI) in a swine model of cardiac arrest. The primary hypothesis was COI during standard CPR (S-CPR) should result in higher intrathoracic pressure (ITP) during chest compression and lower ITP during decompression versus S-CPR alone. These changes with COI were hypothesized to improve hemodynamics. The second hypothesis was that changes in ITP with S-CPR+COI would result in superior hemodynamics compared with active compression decompression (ACD) + impedance threshold device (ITD) CPR, as this method primarily lowers ITP during chest decompression. After 6min of untreated ventricular fibrillation, S-CPR was initiated in 8 female swine for 4min, then 3min of S-CPR+COI, then 3min of ACD+ITD CPR, then 3min of S-CPR+COI. ITP and hemodynamics were continuously monitored. During S-CPR+COI, ITP was always positive during the CPR compression and decompression phases. ITP compression values with S-CPR+COI versus S-CPR alone were 5.5±3 versus 0.2±2 (p<0.001) and decompression values were 2.8±2 versus -1.3±2 (p<0.001), respectively. With S-CPR+COI versus ACD+ITD the ITP compression values were 5.5±3 versus 1.5±2 (p<0.01) and decompression values were 2.8±2 versus -4.7±3 (p<0.001), respectively. COI during S-CPR created a continuous positive pressure in the airway during both the compression and decompression phase of CPR. At no point in time did COI generate a negative intrathoracic pressures during CPR in this swine model of cardiac arrest. Copyright © 2017 Elsevier B.V. All rights reserved.

Sleep Apnea and Cardiovascular Disease: Lessons From Recent Trials and Need for Team Science.

PubMed

Drager, Luciano F; McEvoy, R Doug; Barbe, Ferran; Lorenzi-Filho, Geraldo; Redline, Susan

2017-11-07

Emerging research highlights the complex interrelationships between sleep-disordered breathing and cardiovascular disease, presenting clinical and research opportunities as well as challenges. Patients presenting to cardiology clinics have a high prevalence of obstructive and central sleep apnea associated with Cheyne-Stokes respiration. Multiple mechanisms have been identified by which sleep disturbances adversely affect cardiovascular structure and function. Epidemiological research indicates that obstructive sleep apnea is associated with increases in the incidence and progression of coronary heart disease, heart failure, stroke, and atrial fibrillation. Central sleep apnea associated with Cheyne-Stokes respiration predicts incident heart failure and atrial fibrillation; among patients with heart failure, it strongly predicts mortality. Thus, a strong literature provides the mechanistic and empirical bases for considering obstructive sleep apnea and central sleep apnea associated with Cheyne-Stokes respiration as potentially modifiable risk factors for cardiovascular disease. Data from small trials provide evidence that treatment of obstructive sleep apnea with continuous positive airway pressure improves not only patient-reported outcomes such as sleepiness, quality of life, and mood but also intermediate cardiovascular end points such as blood pressure, cardiac ejection fraction, vascular parameters, and arrhythmias. However, data from large-scale randomized controlled trials do not currently support a role for positive pressure therapies for reducing cardiovascular mortality. The results of 2 recent large randomized controlled trials, published in 2015 and 2016, raise questions about the effectiveness of pressure therapies in reducing clinical end points, although 1 trial supported the beneficial effect of continuous positive airway pressure on quality of life, mood, and work absenteeism. This review provides a contextual framework for interpreting the results of recent studies, key clinical messages, and suggestions for future sleep and cardiovascular research, which include further consideration of individual risk factors, use of existing and new multimodality therapies that also address adherence, and implementation of trials that are sufficiently powered to target end points and to support subgroup analyses. These goals may best be addressed through strengthening collaboration among the cardiology, sleep medicine, and clinical trial communities. © 2017 American Heart Association, Inc.

Neuroendocrine and Inflammatory Responses to Losartan and Continuous Positive Airway Pressure in Patients with Hypertension and Obstructive Sleep Apnea. A Randomized Controlled Trial.

PubMed

Thunström, Erik; Manhem, Karin; Yucel-Lindberg, Tülay; Rosengren, Annika; Lindberg, Caroline; Peker, Yüksel

2016-11-01

Blood pressure reduction in response to antihypertensive agents is less for patients with obstructive sleep apnea (OSA). Increased sympathetic and inflammatory activity, as well as alterations in the renin-angiotensin-aldosterone system, may play a role in this context. To address the cardiovascular mechanisms involved in response to an angiotensin II receptor antagonist, losartan, and continuous positive airway pressure (CPAP) as add-on treatment for hypertension and OSA. Newly diagnosed hypertensive patients with or without OSA (allocated in a 2:1 ratio for OSA vs. no OSA) were treated with losartan 50 mg daily during a 6-week two-center, open-label, prospective, case-control, parallel-design study. In the second 6-week, sex-stratified, open-label, randomized, parallel-design study, all subjects with OSA continued to receive losartan and were randomly assigned to either CPAP as add-on therapy or to no CPAP (1:1 ratio for CPAP vs. no CPAP). Study subjects without OSA were followed in parallel while they continued to take losartan. Blood samples were collected at baseline, after 6 weeks, and after 12 weeks for analysis of renin, aldosterone, noradrenaline, adrenaline, and inflammatory markers. Fifty-four patients with OSA and 35 without OSA were included in the first 6-week study. Losartan significantly increased renin levels and reduced aldosterone levels in the group without OSA. There was no significant decrease in aldosterone levels among patients with OSA. Add-on CPAP treatment tended to lower aldosterone levels, but reductions were more pronounced in measures of sympathetic activity. No significant changes in inflammatory markers were observed following treatment with losartan and CPAP. Hypertensive patients with OSA responded to losartan treatment with smaller reductions in aldosterone compared with hypertensive patients without OSA. Sympathetic system activity seemed to respond primarily to add-on CPAP treatment in patients with newly discovered hypertension and OSA. Clinical trial registered with www.clinicaltrials.gov (NCT00701428).

[Hypoglossal nerve stimulation in patients with CPAP failure : Evolution of an alternative treatment for patients with obstructive sleep apnea].

PubMed

Heiser, C; Hofauer, B

2017-02-01

Obstructive sleep apnea (OSA) is a common disease in western industrialized countries with increasing prevalence. Gold standard of therapy is nocturnal positive pressure ventilation by continuous positive airway pressure (CPAP). Due to complications and side effects of ventilation, therapy adherence is limited. Recently an alternative surgical treatment has become available for these patients, which uses established techniques to stimulate the hypoglossus nerve to open the upper airway during sleep. The aim of this work is to provide an overview of the history and current state of scientific knowledge of this therapy in the treatment of OSA. Currently, two systems are available on the market: respiratory-driven hypoglossal nerve stimulation (Inspire Medical Systems) and continuous hypoglossal nerve stimulation (ImThera Medical). For respiratory-driven hypoglossal nerve stimulation, a solid body of evidence is available and the therapy has been investigated in numerous multicenter clinical studies with regard to safety and efficacy. Only a small number of publications is available for continuous hypoglossal nerve stimulation. At the end of the last century, promising clinical results were shown in the first patients treated with hypoglossal nerve stimulation. Consequent technological and scientific development of respiratory-driven hypoglossal nerve stimulation in recent years led to its implementation in today's clinical routine. This therapy significantly broadens the spectrum of therapies in the treatment of OSA, especially for patients with CPAP intolerance.

The changes on physical characteristics of lightning discharge plasma during individual return stroke process

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

Xu, He; Yuan, Ping; Cen, Jian-Yong

2014-03-15

A cloud-to-ground lightning with six return strokes has been recorded with a slit-less spectrograph in Qinghai province. According to the spectra of return strokes without continuous current, the electron density, the channel temperature, and the gas pressure have been calculated. Then, the correlativity of these parameters has been analyzed. The results indicate that the total intensity of spectra is positive correlated to the intensity of spectral line, they both decrease with time rapidly; furthermore, the channel temperature and the gas pressure decrease with time slowly in the similar trends.

Analysis of healthy sitting behavior: interface pressure distribution and subcutaneous tissue oxygenation.

PubMed

Reenalda, Jasper; Van Geffen, Paul; Nederhand, Marc; Jannink, Michiel; IJzerman, Maarten; Rietman, Hans

2009-01-01

Pressure ulcers are a large problem in individuals who use a wheelchair for their mobility and have limited trunk stability and motor function. Because no relation between interface pressure and pressure ulcer development has been established and no clinical threshold for pressure ulcer development can be given, looking at the sitting behavior of nondisabled individuals is important. Nondisabled individuals do not develop pressure ulcers because they continuously shift posture. We analyzed the sitting behavior of 25 nondisabled male subjects by using a combination of interface pressure measurement and subcutaneous tissue oxygenation measurement by means of the Oxygen to See. These subjects shifted posture on average 7.8 +/- 5.2 times an hour. These posture shifts were merely a combination of posture shifts in the frontal and sagittal plane. Subcutaneous oxygen saturation increased on average 2.2% with each posture adjustment, indicating a positive effect of posture shifts on tissue viability. The results of this study can be used as a reference for seating interventions aimed at preventing pressure ulcers. Changing the sitting load at least every 8 minutes is recommended for wheelchair users.

ROLE OF SPOUSAL INVOLVEMENT IN CONTINUOUS POSITIVE AIRWAY PRESSURE (CPAP) ADHERENCE IN PATIENTS WITH OBSTRUCTIVE SLEEP APNEA (OSA)

PubMed Central

Batool-Anwar, Salma; Baldwin, Carol M.; Fass, Shira; Quan, Stuart F.

2017-01-01

Introduction Little is known about the impact of spousal involvement on continuous positive airway pressure (CPAP) adherence. The aim of this study was to determine whether spouse involvement affects adherence with CPAP therapy, and how this association varies with gender. Methods 194 subjects recruited from Apnea Positive Pressure Long Term Efficacy Study (APPLES) completed the Dyadic Adjustment Scale (DAS). The majority of participants were Caucasian (83%), and males (73%), with mean age of 56 years, mean BMI of 31 kg/m2. & 62% had severe OSA. The DAS is a validated 32-item self-report instrument measuring dyadic consensus, satisfaction, cohesion, and affectional expression. A high score in the DAS is indicative of a person’s adjustment to the marriage. Additionally, questions related to spouse involvement with general health and CPAP use were asked. CPAP use was downloaded from the device and self-report, and compliance was defined as usage ≥ 4 h per night. Results There were no significant differences in overall marital quality between the compliant and noncompliant subjects. However, level of spousal involvement was associated with increased CPAP adherence at 6 months (p=0.01). After stratifying for gender these results were significant only among males (p=0.03). Three years after completing APPLES, level of spousal involvement was not associated with CPAP compliance even after gender stratification. Conclusion Spousal involvement is important in determining CPAP compliance in males in the 1st 6 months after initiation of therapy but is not predictive of longer-term adherence. Involvement of the spouse should be considered an integral part of CPAP initiation procedures. Support HL068060 PMID:28725492

The stable microbubble test for determining continuous positive airway pressure (CPAP) success in very preterm infants receiving nasal CPAP from birth.

PubMed

Bhatia, Risha; Morley, Colin J; Argus, Brenda; Tingay, David G; Donath, Susan; Davis, Peter G

2013-01-01

Very preterm infants can be treated with nasal continuous positive airway pressure (CPAP) from birth, but some fail. A rapid test, such as the stable microbubble test (SMT) on gastric aspirate, may identify those who can be managed successfully using CPAP. To determine if SMT can identify soon after birth, very preterm infants who may be successfully managed on CPAP alone. Stable microbubbles (diameter <15 µm) were counted in gastric aspirates taken <1 h of age from infants <30 weeks' gestation, who received CPAP from birth. Infants failed CPAP if intubated at <72 h of age. Clinicians were masked to SMT results. A receiver operating characteristic curve was generated to determine the relationship between number of microbubbles/mm(2) and subsequent intubation. 68 infants of mean (SD) 28.1 (1.4) weeks' gestation received CPAP in the delivery room at a median (interquartile range) pressure 7 (6-8) cmH2O and FiO2 0.25 (0.21-0.3). Gastric aspirates were taken at a median (interquartile range) age of 0.5 (0.3-0.6) hours. The best cut-off point for predicting CPAP success or failure was a SMT count of 8 microbubbles/mm(2). The area under the receiver operating characteristic curve was 0.8 (95% CI 0.7-0.9). A SMT count ≥8 microbubbles/mm(2) had a sensitivity of 53%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 60% for predicting CPAP success. Infants treated with CPAP from birth, who had SMT counts ≥8 microbubbles/mm(2) on their gastric aspirate, did not fail CPAP. Copyright © 2013 S. Karger AG, Basel.

Bubble CPAP versus CPAP with variable flow in newborns with respiratory distress: a randomized controlled trial.

PubMed

Yagui, Ana Cristina Zanon; Vale, Luciana Assis Pires Andrade; Haddad, Luciana Branco; Prado, Cristiane; Rossi, Felipe Souza; Deutsch, Alice D Agostini; Rebello, Celso Moura

2011-01-01

To evaluate the efficacy and safety of nasal continuous positive airway pressure (NCPAP) using devices with variable flow or bubble continuous positive airway pressure (CPAP) regarding CPAP failure, presence of air leaks, total CPAP and oxygen time, and length of intensive care unit and hospital stay in neonates with moderate respiratory distress (RD) and birth weight (BW) ≥ 1,500 g. Forty newborns requiring NCPAP were randomized into two study groups: variable flow group (VF) and continuous flow group (CF). The study was conducted between October 2008 and April 2010. Demographic data, CPAP failure, presence of air leaks, and total CPAP and oxygen time were recorded. Categorical outcomes were tested using the chi-square test or the Fisher's exact test. Continuous variables were analyzed using the Mann-Whitney test. The level of significance was set at p < 0.05. There were no differences between the groups with regard to demographic data, CPAP failure (21.1 and 20.0% for VF and CF, respectively; p = 1.000), air leak syndrome (10.5 and 5.0%, respectively; p = 0.605), total CPAP time (median: 22.0 h, interquartile range [IQR]: 8.00-31.00 h and median: 22.0 h, IQR: 6.00-32.00 h, respectively; p = 0.822), and total oxygen time (median: 24.00 h, IQR: 7.00-85.00 h and median: 21.00 h, IQR: 9.50-66.75 h, respectively; p = 0.779). In newborns with BW ≥ 1,500 g and moderate RD, the use of continuous flow NCPAP showed the same benefits as the use of variable flow NCPAP.

Comparative Effects of Volutrauma and Atelectrauma on Lung Inflammation in Experimental Acute Respiratory Distress Syndrome

PubMed Central

Güldner, Andreas; Braune, Anja; Ball, Lorenzo; Silva, Pedro L.; Samary, Cynthia; Insorsi, Angelo; Huhle, Robert; Rentzsch, Ines; Becker, Claudia; Oehme, Liane; Andreeff, Michael; Vidal Melo, Marcos F.; Winkler, Tilo; Pelosi, Paolo; Rocco, Patricia R. M.; Kotzerke, Jörg; de Abreu, Marcelo Gama

2016-01-01

Objective Volutrauma and atelectrauma promote ventilator-induced lung injury, but their relative contribution to inflammation in ventilator-induced lung injury is not well established. The aim of this study was to determine the impact of volutrauma and atelectrauma on the distribution of lung inflammation in experimental acute respiratory distress syndrome. Design Laboratory investigation. Setting University-hospital research facility. Subjects Ten pigs (five per group; 34.7–49.9 kg) Interventions Animals were anesthetized and intubated, and saline lung lavage was performed. Lungs were separated with a double-lumen tube. Following lung recruitment and decremental positive end-expiratory pressure trial, animals were randomly assigned to 4 hours of ventilation of the left (ventilator-induced lung injury) lung with tidal volume of approximately 3 mL/kg and 1) high positive end-expiratory pressure set above the level where dynamic compliance increased more than 5% during positive end-expiratory pressure trial (volutrauma); or 2) low positive end-expiratory pressure to achieve driving pressure comparable with volutrauma (atelectrauma). The right (control) lung was kept on continuous positive airway pressure of 20 cm H2O, and Co2 was partially removed extracorporeally. Measurements and Main Results Regional lung aeration, specific [18F]fluorodeoxyglucose uptake rate, and perfusion were assessed using computed and positron emission tomography. Volutrauma yielded higher [18F]fluorodeoxyglucose uptake rate in the ventilated lung compared with atelectrauma (median [interquartile range], 0.017 [0.014–0.025] vs 0.013 min−1 [0.010–0.014min−1]; p < 0.01), mainly in central lung regions. Volutrauma yielded higher [18F]fluorodeoxyglucose uptake rate in ventilator-induced lung injury versus control lung (0.017 [0.014–0.025] vs 0.011 min−1 [0.010–0.016min−1]; p < 0.05), whereas atelectrauma did not. Volutrauma decreased blood fraction at similar perfusion and increased normally as well as hyper-aerated lung compartments and tidal hyperaeration. Atelectrauma yielded higher poorly and nonaerated lung compartments, and tidal recruitment. Driving pressure increased in atelectrauma. Conclusions In this model of acute respiratory distress syndrome, volutrauma promoted higher lung inflammation than atelectrauma at comparable low tidal volume and lower driving pressure, suggesting that static stress and strain are major determinants of ventilator-induced lung injury. PMID:27035236

The Effect of Treatment of Obstructive Sleep Apnea on Quality of Life in Children with Cerebral Palsy

ERIC Educational Resources Information Center

Hsiao, Kai Hsun; Nixon, Gillian M.

2008-01-01

Benefits of treatment for obstructive sleep apnea (OSA) in children with cerebral palsy could differ from those in otherwise healthy children. We examined the effects of OSA treatment by comparing a group of children with cerebral palsy treated with adenotonsillectomy or continuous positive airway pressure (CPAP) by nasal mask with controls who…

Effect of continuous positive airway pressure (CPAP) therapy on IL-23 in patients with obstructive sleep apnea.

PubMed

Can, Murat; Uygur, Fırat; Tanrıverdi, Hakan; Acıkgoz, Bilgehan; Alper, Barıs; Guven, Berrak

2016-12-01

Obstructive sleep apnea syndrome (OSAS) is a common sleep disorder characterized by repeated episodes of apnea and hypopnea during sleep. Continuous positive airway pressure (CPAP) is the most effective method for treating OSAS and alleviating the patients' symptoms. The aim of this study was to assess the effect of 3-month CPAP therapy on serum levels of IL-23 in patients with OSAS. Twenty-three patients with newly diagnosed moderate-to-severe OSAS who had not yet started nasal CPAP treatment were prospectively enrolled. All of the subjects underwent simple spirometry and an overnight sleep study. Twenty-seven healthy individuals without OSAS were also recruited as the control group. Serum IL-23 and C-reactive protein (CRP) levels were measured before and after 3 months of CPAP therapy. There was no significant difference between moderate and severe OSAS patients in IL-23 and CRP, but both parameters were significantly higher than control group. The CPAP treatment produced a significant decrease in the levels of the inflammatory mediators CRP and IL-23 in patients. Changes in IL-23 were positively correlated with changes in AHI and in CRP. In conclusion, based on these results, serum IL-23 levels reflect OSAS-related systemic inflammation and are a useful marker for improvement in OSAS following CPAP therapy.

Continuous Positive Airway Pressure Treatment for Sleep Apnea in Older Adults

PubMed Central

Weaver, Terri E; Chasens, Eileen

2007-01-01

Daytime sleepiness and sleep disordered breathing are increased in older compared to middle-aged adults. The cognitive and cardiovascular sequelae associated with obstructive sleep apnea (OSA) have significant implications for the older adult who may already be suffering from chronic illness. Most of the evidence supporting the utilization of continuous positive airway pressure (CPAP) for the treatment of OSA has been generated from studies employing samples consisting predominately of middle-aged adults. To examine the efficacy of CPAP for the treatment of obstructive sleep apnea in older adults with an emphasis on adherence and related treatment outcomes, this paper reviews findings from clinical trials including older individuals as well as those specifically targeting this population. These studies have demonstrated that following CPAP therapy, older adults have increased alertness, improved neurobehavioral outcomes in cognitive processing, memory, and executive function, decreased sleep disruption from nocturia and a positive effect on factors affecting cardiac function, including vascular resistance, platelet coagulability and other aspects of cardiovascular health. Physiological differences in respiratory structure and function between younger and older adults of similar disease severity are believed to result in older individuals requiring titration at lower CPAP levels. Once initiated, CPAP treatment is tolerated by older adults, including those with Alzheimer’s disease. Patterns of adherence in older individuals are consistent with that of middle-aged adults. PMID:17275370

Impact of the type of mask on the effectiveness of and adherence to continuous positive airway pressure treatment for obstructive sleep apnea.

PubMed

Andrade, Rafaela Garcia Santos de; Piccin, Vivien Schmeling; Nascimento, Juliana Araújo; Viana, Fernanda Madeiro Leite; Genta, Pedro Rodrigues; Lorenzi-Filho, Geraldo

2014-01-01

Continuous positive airway pressure (CPAP) is the gold standard for the treatment of obstructive sleep apnea (OSA). Although CPAP was originally applied with a nasal mask, various interfaces are currently available. This study reviews theoretical concepts and questions the premise that all types of interfaces produce similar results. We revised the evidence in the literature about the impact that the type of CPAP interface has on the effectiveness of and adherence to OSA treatment. We searched the PubMed database using the search terms "CPAP", "mask", and "obstructive sleep apnea". Although we identified 91 studies, only 12 described the impact of the type of CPAP interface on treatment effectiveness (n = 6) or adherence (n = 6). Despite conflicting results, we found no consistent evidence that nasal pillows and oral masks alter OSA treatment effectiveness or adherence. In contrast, most studies showed that oronasal masks are less effective and are more often associated with lower adherence and higher CPAP abandonment than are nasal masks. We concluded that oronasal masks can compromise CPAP OSA treatment adherence and effectiveness. Further studies are needed in order to understand the exact mechanisms involved in this effect.

Impact of the type of mask on the effectiveness of and adherence to continuous positive airway pressure treatment for obstructive sleep apnea*

PubMed Central

de Andrade, Rafaela Garcia Santos; Piccin, Vivien Schmeling; Nascimento, Juliana Araújo; Viana, Fernanda Madeiro Leite; Genta, Pedro Rodrigues; Lorenzi-Filho, Geraldo

2014-01-01

Continuous positive airway pressure (CPAP) is the gold standard for the treatment of obstructive sleep apnea (OSA). Although CPAP was originally applied with a nasal mask, various interfaces are currently available. This study reviews theoretical concepts and questions the premise that all types of interfaces produce similar results. We revised the evidence in the literature about the impact that the type of CPAP interface has on the effectiveness of and adherence to OSA treatment. We searched the PubMed database using the search terms "CPAP", "mask", and "obstructive sleep apnea". Although we identified 91 studies, only 12 described the impact of the type of CPAP interface on treatment effectiveness (n = 6) or adherence (n = 6). Despite conflicting results, we found no consistent evidence that nasal pillows and oral masks alter OSA treatment effectiveness or adherence. In contrast, most studies showed that oronasal masks are less effective and are more often associated with lower adherence and higher CPAP abandonment than are nasal masks. We concluded that oronasal masks can compromise CPAP OSA treatment adherence and effectiveness. Further studies are needed in order to understand the exact mechanisms involved in this effect. PMID:25610507

Oronasal mask may compromise the efficacy of continuous positive airway pressure on OSA treatment: is there evidence for avoiding the oronasal route?

PubMed

Andrade, Rafaela Garcia Santos; Madeiro, Fernanda; Genta, Pedro Rodrigues; Lorenzi-Filho, Geraldo

2016-11-01

Continuous positive airway pressure (CPAP) delivered by nasal mask is the gold standard treatment for obstructive sleep apnea (OSA). However, oral and oronasal masks are also available. We considered experimental evidence and reviewed clinical trials that evaluated the impact of oral and oronasal mask on OSA treatment. One recent study in 18 OSA patients that slept with a customized oronasal mask with two sealed compartments showed that the change of CPAP flow from nasal to oronasal and oral caused upper airway obstruction because of posterior displacement of the tongue demonstrated by nasoendoscopy. Oral masks use a mouthpiece that may stabilize the jaw and the tongue and have shown to be effective. However, oral masks are not widely used in clinical practice. Four out of five observational studies and all five reviewed randomized studies showed a worse performance of oronasal when compared with nasal masks. Oronasal masks were associated with higher residual apnea-hypopnea index, lower adherence, more leaks, and less satisfaction than nasal mask in the majority of the studies. Nasal CPAP must be the first choice to treat OSA. Patients on oronasal mask should be carefully followed. VIDEO ABSTRACT.

Continuous positive airway pressure machines and the work of coordinating technologies at home.

PubMed

Moreira, Tiago

2008-06-01

Research on the use of health technology at home has consistently reported that it is underpinned by users' evaluations of the technology in relation to their illness trajectory, their social network, and the place where it is used. Recent studies have also revealed that the efficacy of health technologies depends upon users' work that is largely invisible to professionals, managers and designers. This paper draws on the most widely used therapy for the management of sleep apnoea, continuous positive airway pressure (CPAP), to show how users maintain workable relationships between it and other technological elements of the domestic environment. Qualitative analysis was performed of an archive of messages sent to a web-based support group for sleep disorders between 1994 and 2007. Users describe two related techniques: first, drawing on their embodied knowledge of using domestic technologies to imagine potential, alternative environments for CPAP; and second, using their body as an instrument to assess the ;fit' of each of the attempted arrangements. The interaction between these two techniques entails frequent shifts in users' understandings of their illness and those involved in its management. Strategies of implementation of health technologies at home should acknowledge and incorporate the embodied knowledge processes of users.

Does continuous positive airway pressure reduce aldosterone levels in patients with obstructive sleep apnea?

PubMed

Yang, Si-Jiu; Jiang, Xing-Tang; Zhang, Xiao-Bin; Yin, Xiao-Wen; Deng, Wei-Xian

2016-09-01

Aldosterone is associated with the development of obstructive sleep apnea (OSA) and cardiovascular diseases. Continuous positive airway pressure (CPAP) is an effective treatment for OSA, but the impact of CPAP therapy on aldosterone levels in patients with OSA remains unclear. To address this issue, a meta-analysis was conducted to evaluate the effects of CPAP therapy on serum aldosterone levels in OSA. Two reviewers independently searched PubMed, Cochrane library, Embase, and Web of Science before March 2015. Information on characteristics of subjects, study design, and pre- and post-CPAP treatment of serum aldosterone was extracted for analysis. Standardized mean difference (SMD) was calculated to estimate the treatment effects of CPAP therapy. A total of 5 studies involving 329 patients were pooled into this meta-analysis, including 3 observational studies and 2 randomized controlled studies. Results indicated significantly decreased aldosterone levels after CPAP therapy (SMD = -0.236, 95 % confidence interval (CI) = -0.45 to -0.02, z = 2.12, p = 0.034). This meta-analysis suggested that CPAP therapy was associated with a decrease in serum aldosterone in patients with OSA. Further large-scale, well-designed interventional investigations are needed to clarify this issue.

Labour room Continuous Positive Airway Pressure (LR CPAP) in preterm neonates <34 weeks: An Indian experience.

PubMed

Desai, Saumil Ashvinkumar; Tule, Pankaj; Nanavati, Ruchi Nimish

2017-01-01

Early continuous positive airway pressure (CPAP) has proven to be beneficial in reducing ventilator dependence and subsequent chronic lung disease in neonates suffering from Respiratory distress syndrome (RDS). However, the efficacy of initiating labour room (LR) CPAP has not been determined prospectively in resource limited settings like India. Hence the objective of the present study was to study the efficacy of LR CPAP in preterm neonates with RDS in resource limited Indian settings. This was a prospective observational study including preterm neonates (26-34 weeks with RDS) carried out over a period of 6 months (January to June 2016) when the CPAP was initiated in LR. The outcome was compared with a similar population during the corresponding period of the previous year when CPAP was initiated in NICU. The historical controls were retrieved from case records and matched for gestational age and birth weight with the study population. There was 36% absolute risk reduction in the need for surfactant and 56% for mechanical ventilation in the LR CPAP group respectively. LR CPAP reduces the need for mechanical ventilation and surfactant in preterm neonates with RDS in resource limited settings.

Determinants of compliance with nasal continuous positive airway pressure treatment applied in a community setting.

PubMed

Ball, E M.; Banks, M B.

2001-05-01

Objectives: To assess determinants of nasal continuous positive airway pressure (CPAP) compliance when applied in a community setting.Background: One-third of obstructive sleep apnea patients eventually refuse CPAP therapy. Treatment outcomes may be improved by identifying predictors of CPAP failure, including whether management by primary care physicians without sleep consultation affects results.Methods: Polysomnogram, chart review, and questionnaire results for regular CPAP users (n=123) were compared with those returning the CPAP machine (n=26).Results: Polysomnographic data and the presence of multiple sleep disorders were only modestly predictive of CPAP compliance. Striking differences in questionnaire responses separated CPAP users from non-users, who reported less satisfaction with all phases of their diagnosis and management. Rates of CPAP use were not significantly different between patients managed solely by their primary care physician or by a sleep consultant.Conclusions: Polysomnographic findings are unlikely to identify eventual CPAP non-compliers in a cost-effective fashion. Improvements in sleep apnea management may result from addressing the role of personality factors and multiple sleep disorders in determining compliance. In this practice setting, management by primary care physicians did not significantly degrade CPAP compliance.

Retrograde air escape via the nasolacrimal system: a previously unrecognized complication of continuous positive airway pressure in the management of obstructive sleep apnea.

PubMed

Singh, Narinder Pal; Walker, Robbie James Eades; Cowan, Fiona; Davidson, Arthur Craig; Roberts, David Newton

2014-05-01

Continuous positive airway pressure (CPAP) is the gold standard treatment for moderate to severe obstructive sleep apnoea (OSA). Eye-related side effects of CPAP are commonly attributed to a poorly sealed mask, allowing leaked air to blow over the eye. We present 3 cases where attended polysomnography (A-PSG) demonstrated CPAP-associated retrograde air escape via the nasolacrimal system (CRANS) in the absence of any mask leaks. Symptoms included dry eye, epiphora, air escape from the medial canthus, and eyelid flutter. Symptoms were controlled with a variety of surgical and nonsurgical techniques. CRANS represents a previously undescribed clinical entity. CRANS may be responsible for some CPAP-related eye side effects and possibly for rarer secondary eye complications, including conjunctivitis and corneal ulceration. CRANS should be suspected in any patient on CPAP complaining of eye symptoms. CRANS may be diagnosed through careful observation during A-PSG and confirmed by performing a "saline bubble test." Management options include nonsurgical (mask alternatives, humidification, nasopharyngeal airway) and surgical techniques (nasal airway surgery, inferior turbinate out-fracture and adhesion, injection of bulking agent around Hasner's valve).

Neurodevelopmental Outcomes of Extremely Low Birth Weight Infants Ventilated With Continuous Positive Airway Pressure vs. Mechanical Ventilation

PubMed Central

Thomas, Cameron W.; Meinzen-Derr, Jareen; Hoath, Steven B.; Narendran, Vivek

2012-01-01

OBJECTIVE To compare continuous positive airway pressure (CPAP) vs. traditional mechanical ventilation (MV) at 24 h of age as predictors of neurodevelopmental (ND) outcomes in extremely low birth weight (ELBW) infants at 18-22 mo corrected gestational age (CGA). METHODS Infants ≤ 1000g birth weight born from January 2000 through December 2006 at two hospitals at the Cincinnati site of the National Institute of Child Health and Human Development Neonatal Research Network were evaluated comparing CPAP (N = 198) vs. MV (N = 109). Primary outcomes included the Bayley Score of Infant Development Version II (BSID-II), presence of deafness, blindness, cerebral palsy, bronchopulmonary dysplasia and death. RESULTS Ventilatory groups were similar in gender, rates of preterm prolonged rupture of membranes, antepartum hemorrhage, use of antenatal antibiotics, steroids, and tocolytics. Infants receiving CPAP weighed more, were older, were more likely to be non-Caucasian and from a singleton pregnancy. Infants receiving CPAP had better BSID-II scores, and lower rates of BPD and death. CONCLUSIONS After adjusting for acuity differences, ventilatory strategy at 24 h of age independently predicts long-term neurodevelopmental outcome in ELBW infants. PMID:21853318

Incentive spirometry for preventing pulmonary complications after coronary artery bypass graft.

PubMed

Freitas, E R F S; Soares, B G O; Cardoso, J R; Atallah, A N

2007-07-18

Following coronary artery bypass graft (CABG), the main causes of postoperative morbidity and mortality are postoperative pulmonary complications, respiratory dysfunction and arterial hypoxemia. Incentive spirometry is a treatment technique that uses a mechanical device (an incentive spirometer) to reduce such pulmonary complications during postoperative care. To assess the effects of incentive spirometry for preventing postoperative pulmonary complications in adults undergoing CABG. We searched CENTRAL on The Cochrane Library (Issue 2, 2004), MEDLINE (1966 to December 2004), EMBASE (1980 to December 2004), LILACS (1982 to December 2004), the Physiotherapy Evidence Database (PEDro) (1980 to December 2004), Allied & Complementary Medicine (AMED) (1985 to December 2004), CINAHL (1982 to December 2004), and the Database of Abstracts of Reviews of Effects (DARE) (1994 to December 2004). References were checked and authors contacted. No language restrictions were applied. Randomized controlled trials comparing incentive spirometry with any type of prophylactic physiotherapy for prevention of postoperative pulmonary complications in adults undergoing CABG. Two reviewers independently evaluated the quality of trials using the guidelines of the Cochrane Reviewers' Handbook and extracted data from included trials. Four trials with 443 participants contributed to this review. There was no significant difference in pulmonary complications (atelectasis and pneumonia) between treatment with incentive spirometry and treatment with positive pressure breathing techniques (continuous positive airway pressure (CPAP), bilevel positive airway pressure (BiPAP) and intermittent positive pressure breathing (IPPB)) or preoperative patient education. Patients treated with incentive spirometry had worse pulmonary function and arterial oxygenation compared with positive pressure breathing (CPAP, BiPAP, IPPB). Individual small trials suggest that there is no evidence of benefit from incentive spirometry in reducing pulmonary complications and in decreasing the negative effects on pulmonary function in patients undergoing CABG. In view of the modest number of patients studied, methodological shortcomings and poor reporting of the included trials, these results should be interpreted cautiously. An appropriately powered trial of high methodological rigour is needed to determine those patients who may derive benefit from incentive spirometry following CABG.

Relationship between pre-extubation positive endexpiratory pressure and oxygenation after coronary artery bypass grafting

PubMed Central

Lima, Reijane Oliveira; Borges, Daniel Lago; Costa, Marina de Albuquerque Gonçalves; Baldez, Thiago Eduardo Pereira; Silva, Mayara Gabrielle Barbosa e; Sousa, Felipe André Silva; Soares, Milena de Oliveira; Pinto, Jivago Gentil Moreira

2015-01-01

Introduction After removal of endotracheal tube and artificial ventilation, ventilatory support should be continued, offering oxygen supply to ensure an arterial oxygen saturation close to physiological. Objective The aim of this study was to investigate the effects of positive-end expiratory pressure before extubation on the oxygenation indices of patients undergoing coronary artery bypass grafting. Methods A randomized clinical trial with seventy-eight patients undergoing coronary artery bypass grafting divided into three groups and ventilated with different positive-end expiratory pressure levels prior to extubation: Group A, 5 cmH2O (n=32); Group B, 8 cmH2O (n=26); and Group C, 10 cmH2O (n=20). Oxygenation index data were obtained from arterial blood gas samples collected at 1, 3, and 6 h after extubation. Patients with chronic pulmonary disease and those who underwent off-pump, emergency, or combined surgeries were excluded. For statistical analysis, we used Shapiro-Wilk, G, Kruskal-Wallis, and analysis of variance tests and set the level of significance at P<0.05. Results Groups were homogenous with regard to demographic, clinical, and surgical variables. There were no statistically significant differences between groups in the first 6 h after extubation with regard to oxygenation indices and oxygen therapy utilization. Conclusion In this sample of patients undergoing coronary artery bypass grafting, the use of different positive-end expiratory pressure levels before extubation did not affect gas exchange or oxygen therapy utilization in the first 6 h after endotracheal tube removal. PMID:27163418

Interactive effect of body posture on exercise-induced atrial natriuretic peptide release.

PubMed

Ray, C A; Delp, M D; Hartle, D K

1990-05-01

The purpose of this investigation was to test the hypothesis that supine exercise elicits a greater atrial natriuretic peptide (ANP) response than upright exercise because of higher atrial filling pressure attained in the supine posture. Plasma ANP concentration ([ANP]) was measured during continuous graded supine and upright exercise in eight healthy men at rest after 4 min of cycling exercise at 31, 51, and 79% of posture-specific peak oxygen uptake (VO2 peak), after 2 min of cycling at posture-specific VO2 peak, and 5 and 15 min postexercise. [ANP] was significantly increased (P less than 0.05) above rest by 64, 140, and 228% during supine cycling at 51 and 79% and VO2 peak, respectively. During upright cycling, [ANP] was significantly increased (P less than 0.05) at 79% (60%) and VO2 peak (125%). After 15 min of postexercise rest, [ANP] remained elevated (P less than 0.05) only in the supine subjects. [ANP] was 63, 79, and 75% higher (P less than 0.05) in the supine than in the upright position during cycling at 51 and 79% and VO2 peak. Systolic, diastolic, and mean blood pressures were not significantly (P greater than 0.05) different between positions in all measurement periods. Heart rates were lower (P less than 0.05) in the supine position compared with the upright position. In conclusion, these results suggest that supine exercise elicits greater ANP release independent of blood pressure and heart rate but presumably caused by greater venous return, central blood volume, and concomitant atrial filling pressure and stretch.

Effects of Aerobic Exercise Training on Psychosocial Status and Serum Uric Acid in Men with Essential Hypertension: A Randomized Controlled Trial

PubMed Central

Lamina, S; Okoye, GC

2012-01-01

Background: Chronic psychosocial stress and serum uric acid (SUA) level have been implicated in the etiology and cardiovascular events risk factors in hypertension. Studies have reported significant benefit of exercise in the overall management of hypertension. However, studies on the effect of exercise on psychosocial stress and SUA in the management of hypertension seem scanty. Aim: The aim of this study was to determine the effect of continuous training program on SUA and psychosocial status of black African (Nigerian) population with hypertension. Subjects and Methods: Age-matched randomized controlled trial was used; subjects with diagnosis of hypertension attending the hypertensive clinic of Murtala Muhammed Specialist Hospital (MMSH), Kano, Nigeria form the population for the study. Two hundred and seventeen subjects with mild to moderate (systolic blood pressure (SBP) between 140 and180 and diastolic blood pressure (DBP) between 90 and 109 mmHg) essential hypertension were grouped into continuous (112) and control groups (105). The continuous group involved in an 8 weeks continuous training (60%-79% HR max) of between 45 and 60 min, 3 times per week, while the controls group remain sedentary. SBP, DBP, SUA, VO2 max and psychosocial status were assessed. Student t-test and Pearson correlation test were used in data analysis. Results: The study revealed significant beneficial effect of continuous training programs on VO2 max, SBP, DBP, SUA, and psychosocial status (P < 0.05). Psychosocial status and SUA was significantly and positively and negatively correlated respectively with VO2 max at P < 0.01. Conclusions: This study concludes and supports the recommendations of moderate intensity (continuous) training program in blood pressure reduction, SUA and psychosocial stress management in hypertension. PMID:23439606

A forskolin derivative, colforsin daropate hydrochloride, inhibits the decrease in cortical renal blood flow induced by noradrenaline or angiotensin II in anesthetized rats.

PubMed

Ogata, Junichi; Minami, Kouichiro; Segawa, Kayoko; Uezono, Yasuhito; Shiraishi, Munehiro; Yamamoto, Chikako; Sata, Takeyoshi; Sung-Teh, Kim; Shigematsu, Akio

2004-01-01

A forskolin derivative, colforsin daropate hydrochloride (CDH), acts directly on adenylate cyclase to increase the intracellular cyclic adenosine monophosphate levels which produce a positive inotropic effect and a lower blood pressure. However, little is known about the effects of CDH on the renal function. We used laser Doppler flowmetry to measure the cortical renal blood flow (RBF) in male Wistar rats given a continuous intravenous infusion of CDH and evaluated the effects of CDH on the noradrenaline (NA) and angiotensin II (AngII) induced increases in blood pressure and reductions in RBF. Continuous intravenous administration of CDH at 0.25 microg/kg/min did not affect the mean arterial pressure (MAP), but increased heart rate and RBF. Continuous intravenous administration of CDH at high doses (0.5-0.75 microg/kg/min) decreased the MAP, with little effect on the RBF. The administration of exogenous NA (1.7 microg/kg) increased the MAP and decreased the RBF. However, a bolus injection of NA did not decrease the RBF during continuous intravenous administration of CDH, and CDH did not affect the NA-induced increase in MAP. The administration of exogenous AngII (100 ng/kg) increased MAP and decreased RBF and heart rate, but a bolus injection of AngII did not decrease RBF during continuous intravenous administration of CDH. These results suggest that CDH plays a protective role against the pressor effects and the decrease in RBF induced by NA or AngII. Copyright 2004 S. Karger AG, Basel

Long-term use of neonatal helmet-CPAP: a case report.

PubMed

Doglioni, N; Micaglio, M; Zanardo, V; Trevisanuto, D

2009-12-01

In a recent short-term physiological study, we demonstrated a new continuous positive airway pressure (CPAP) system (neonatal helmet-CPAP) that could be a feasible device for managing preterm infants needing continuous distending pressure with better tolerability than nasal-CPAP. However, its application for a long-term period has never been reported in neonates. Here, we describe the use of neonatal helmet-CPAP in a neonate with persistent pulmonary hypertension of the newborn. Twenty minutes after neonatal helmet-CPAP placement, the baseline post-ductal tcSaO2 (66%) and alveolar-arterial gradient O2 improved from 66% and 648 mmHg to 100% and 465 mmHg, respectively. The neonatal helmet-CPAP was applied for 48 hours and was well-tolerated by the patient without complications. Long-term use of neonatal helmet-CPAP appears feasible and well-tolerated. Comparative trials are needed.

Efficacy of home single-channel nasal pressure for recommending continuous positive airway pressure treatment in sleep apnea.

PubMed

Masa, Juan F; Duran-Cantolla, Joaquin; Capote, Francisco; Cabello, Marta; Abad, Jorge; Garcia-Rio, Francisco; Ferrer, Antoni; Fortuna, Ana M; Gonzalez-Mangado, Nicolas; de la Peña, Monica; Aizpuru, Felipe; Barbe, Ferran; Montserrat, Jose M

2015-01-01

Unlike other prevalent diseases, obstructive sleep apnea (OSA) has no simple tool for diagnosis and therapeutic decision-making in primary healthcare. Home single-channel nasal pressure (HNP) may be an alternative to polysomnography for diagnosis but its use in therapeutic decisions has yet to be explored. To ascertain whether an automatically scored HNP apnea-hypopnea index (AHI), used alone to recommend continuous positive airway pressure (CPAP) treatment, agrees with decisions made by a specialist using polysomnography and several clinical variables. Patients referred by primary care physicians for OSA suspicion underwent randomized polysomnography and HNP. We analyzed the total sample and both more and less symptomatic subgroups for Bland and Altman plots to explore AHI agreement; receiver operating characteristic curves to establish area under the curve (AUC) measurements for CPAP recommendation; and therapeutic decision efficacy for several HNP AHI cutoff points. Of the 787 randomized patients, 35 (4%) were lost, 378 (48%) formed the more symptomatic and 374 (48%) the less symptomatic subgroups. AHI bias and agreement limits were 5.8 ± 39.6 for the total sample, 5.3 ± 38.7 for the more symptomatic, and 6 ± 40.2 for the less symptomatic subgroups. The AUC were 0.826 for the total sample, 0.903 for the more symptomatic, and 0.772 for the less symptomatic subgroups. In the more symptomatic subgroup, 70% of patients could be correctly treated with CPAP. Automatic HNP scoring can correctly recommend CPAP treatment in most of more symptomatic patients with OSA suspicion. Our results suggest that this device may be an interesting tool in initial OSA management for primary care physicians, although future studies in a primary care setting are necessary. Clinicaltrial.gov identifier: NCT01347398. © 2014 Associated Professional Sleep Societies, LLC.

End-expiratory lung volume and ventilation distribution with different continuous positive airway pressure systems in volunteers.

PubMed

Andersson, B; Lundin, S; Lindgren, S; Stenqvist, O; Odenstedt Hergès, H

2011-02-01

Continuous positive airway pressure (CPAP) has been shown to improve oxygenation and a number of different CPAP systems are available. The aim of this study was to assess lung volume and ventilation distribution using three different CPAP techniques. A high-flow CPAP system (HF-CPAP), an ejector-driven system (E-CPAP) and CPAP using a Servo 300 ventilator (V-CPAP) were randomly applied at 0, 5 and 10 cmH₂O in 14 volunteers. End-expiratory lung volume (EELV) was measured by N₂ dilution at baseline; changes in EELV and tidal volume distribution were assessed by electric impedance tomography. Higher end-expiratory and mean airway pressures were found using the E-CPAP vs. the HF-CPAP and the V-CPAP system (P<0.01). EELV increased markedly from baseline, 0 cmH₂O, with increased CPAP levels: 1110±380, 1620±520 and 1130±350 ml for HF-, E- and V-CPAP, respectively, at 10 cmH₂O. A larger fraction of the increase in EELV occurred for all systems in ventral compared with dorsal regions (P<0.01). In contrast, tidal ventilation was increasingly directed toward dorsal regions with increasing CPAP levels (P<0.01). The increase in EELV as well as the tidal volume redistribution were more pronounced with the E-CPAP system as compared with both the HF-CPAP and the V-CPAP systems (P<0.05) at 10 cmH₂O. EELV increased more in ventral regions with increasing CPAP levels, independent of systems, leading to a redistribution of tidal ventilation toward dorsal regions. Different CPAP systems resulted in different airway pressure profiles, which may result in different lung volume expansion and tidal volume distribution. © 2010 The Authors. Journal compilation © 2010 The Acta Anaesthesiologica Scandinavica Foundation.

Cannabis use in people with severe mental illness: The association with physical and mental health--a cohort study. A Pharmacotherapy Monitoring and Outcome Survey study.

PubMed

Bruins, Jojanneke; Pijnenborg, Marieke G H M; Bartels-Velthuis, Agna A; Visser, Ellen; van den Heuvel, Edwin R; Bruggeman, Richard; Jörg, Frederike

2016-04-01

In the general population cannabis use is associated with better cardiometabolic outcomes. Patients with severe mental illness frequently use cannabis, but also present increased cardiometabolic risk factors. We explore the association between cannabis use and cardiometabolic risk factors in patients with severe mental illness. A total of 3169 patients with severe mental illness from a Dutch cohort were included in the study. The association of cannabis use with body mass index, waist circumference, blood pressure, cholesterol, triglycerides, glucose, glycated hemoglobin and Positive and Negative Syndrome Scale was examined with separate univariate AN(C)OVA. Changes in metabolic risk factors and Positive and Negative Syndrome Scale were examined after a follow-up interval of 9-24 months, for patients who continued, discontinued, started or were never using cannabis between the two assessments. Cannabis users at baseline had lower body mass index, smaller waist circumference, lower diastolic blood pressure, and more severe psychotic symptoms than non-users. Patients who discontinued their cannabis use after the first assessment had a greater increase in body mass index, waist circumference, diastolic blood pressure and triglyceride concentrations than other patients, and the severity of their psychotic symptoms had decreased more compared to continued users and non-users. Extra attention should be paid to the monitoring and treatment of metabolic parameters in patients who discontinue their cannabis use. © The Author(s) 2016.

Comparison of sprinting vs non-sprinting to wean nasal continuous positive airway pressure off in very preterm infants.

PubMed

Eze, N; Murphy, D; Dhar, V; Rehan, V K

2018-02-01

Though nasal continuous positive airway pressure (NCPAP) is commonly used for non-invasive neonatal respiratory support, the optimal method of weaning NCPAP is not established. In this prospective, two-center randomized control trial we hypothesize that gradually increasing spontaneous breathing time off NCPAP increases successful weaning from NCPAP in infants born <31 weeks gestational age. Infants were randomized to one of the two NCPAP weaning protocols, a sprinting, that is, gradually increasing spontaneous breathing time off CPAP, protocol vs a non-sprinting (weaning pressure down) protocol. Eighty-six infants were enrolled in one of the two study groups. Thirty-one infants (77%) in the sprinting group and 30 (75%) in the non-sprinting group were successfully weaned off NCPAP at the first attempt (P>0.05). It took 1.3 (1 to 1.75) (median (IQR)) attempts and 7 (7 to 7) days to wean NCPAP off in the sprinting group vs 1.3 (1 to 1.75) attempts and 7 (7 to 10) days in the non-sprinting group (P>0.05). Additionally, no differences in the secondary outcomes of bronchopulmonary dysplasia, severe retinopathy of prematurity (⩾stage 3), periventricular leukomalacia and length of stay were noted between the two groups. Weaning NCPAP via sprinting or non-sprinting protocol is comparable, not only for successful weaning but also for the occurrence of common neonatal morbidities that impact the long-term outcome in premature infants (ClinicalTrials.gov number, NCT02819050).

Microfluidic pressure sensing using trapped air compression.

PubMed

Srivastava, Nimisha; Burns, Mark A

2007-05-01

We have developed a microfluidic method for measuring the fluid pressure head experienced at any location inside a microchannel. The principal component is a microfabricated sealed chamber with a single inlet and no exit; the entrance to the single inlet is positioned at the location where pressure is to be measured. The pressure measurement is then based on monitoring the movement of a liquid-air interface as it compresses air trapped inside the microfabricated sealed chamber and calculating the pressure using the ideal gas law. The method has been used to measure the pressure of the air stream and continuous liquid flow inside microfluidic channels (d approximately 50 microm). Further, a pressure drop has also been measured using multiple microfabricated sealed chambers. For air pressure, a resolution of 700 Pa within a full-scale range of 700-100 kPa was obtained. For liquids, pressure drops as low as 70 Pa were obtained in an operating range from 70 Pa to 10 kPa. Since the method primarily uses a microfluidic sealed chamber, it does not require additional fabrication steps and may easily be incorporated in several lab-on-a-chip fluidic applications for laminar as well as turbulent flow conditions.

Microfluidic pressure sensing using trapped air compression

PubMed Central

Srivastava, Nimisha; Burns, Mark A.

2010-01-01

We have developed a microfluidic method for measuring the fluid pressure head experienced at any location inside a microchannel. The principal component is a microfabricated sealed chamber with a single inlet and no exit; the entrance to the single inlet is positioned at the location where pressure is to be measured. The pressure measurement is then based on monitoring the movement of a liquid–air interface as it compresses air trapped inside the microfabricated sealed chamber and calculating the pressure using the ideal gas law. The method has been used to measure the pressure of the air stream and continuous liquid flow inside microfluidic channels (d ~ 50 μm). Further, a pressure drop has also been measured using multiple microfabricated sealed chambers. For air pressure, a resolution of 700 Pa within a full-scale range of 700–100 kPa was obtained. For liquids, pressure drops as low as 70 Pa were obtained in an operating range from 70 Pa to 10 kPa. Since the method primarily uses a microfluidic sealed chamber, it does not require additional fabrication steps and may easily be incorporated in several lab-on-a-chip fluidic applications for laminar as well as turbulent flow conditions. PMID:17476384

MONITORING OF PORE WATER PRESSURE AND WATER CONTENT AROUND A HORIZONTAL DRIFT THROUGH EXCAVATION - MEASUREMENT AT THE 140m GALLERY IN THE HORONOBE URL -

NASA Astrophysics Data System (ADS)

Yabuuchi, Satoshi; Kunimaru, Takanori; Kishi, Atsuyasu; Komatsu, Mitsuru

Japan Atomic Energy Agency has been conducting the Horonobe Underground Research Laboratory (URL) project in Horonobe, Hokkaido, as a part of the research and development program on geological disposal of high-level radioactive waste. Pore water pressure and water content around a horizontal drift in the URL have been monitored for over 18 months since before the drift excavation was started. During the drift excavation, both pore water pressure and water content were decreasing. Pore water pressure has been still positive though it continued to decrease with its gradient gradually smaller after excavation, while water content turned to increase about 6 months after the completion of the excavation. It turned to fall again about 5 months later. An unsaturated zone containing gases which were dissolved in groundwater may have been formed around the horizontal drift.

Phase diagram of two-dimensional hard ellipses.

PubMed

Bautista-Carbajal, Gustavo; Odriozola, Gerardo

2014-05-28

We report the phase diagram of two-dimensional hard ellipses as obtained from replica exchange Monte Carlo simulations. The replica exchange is implemented by expanding the isobaric ensemble in pressure. The phase diagram shows four regions: isotropic, nematic, plastic, and solid (letting aside the hexatic phase at the isotropic-plastic two-step transition [E. P. Bernard and W. Krauth, Phys. Rev. Lett. 107, 155704 (2011)]). At low anisotropies, the isotropic fluid turns into a plastic phase which in turn yields a solid for increasing pressure (area fraction). Intermediate anisotropies lead to a single first order transition (isotropic-solid). Finally, large anisotropies yield an isotropic-nematic transition at low pressures and a high-pressure nematic-solid transition. We obtain continuous isotropic-nematic transitions. For the transitions involving quasi-long-range positional ordering, i.e., isotropic-plastic, isotropic-solid, and nematic-solid, we observe bimodal probability density functions. This supports first order transition scenarios.

Cervical spine disease may result in a negative lumbar spinal drainage trial in normal pressure hydrocephalus: case report.

PubMed

Komotar, Ricardo J; Zacharia, Brad E; Mocco, J; Kaiser, Michael G; Frucht, Stephen J; McKhann, Guy M

2008-10-01

In this case report, we present a patient with normal pressure hydrocephalus in whom a lumbar drainage trial yielded a false-negative result secondary to cervical spondylosis. An 80-year-old woman presented with classic symptoms of normal pressure hydrocephalus as well as evidence of cervical myelopathy. Magnetic resonance imaging of the brain and spine showed enlarged ventricles and single-level cervical canal narrowing. An initial lumbar drainage trial was performed, which revealed negative results. The patient then underwent cervical decompression and fusion. Despite this procedure, the patient's symptoms continued to worsen. A repeat lumbar drainage trial was performed with positive results. Subsequently, a ventriculoperitoneal shunt was placed, resulting in significant improvement of her symptoms. This case report illustrates how altered cerebrospinal fluid flow dynamics may impact the accuracy of the lumbar spinal drainage trial in patients with normal pressure hydrocephalus.

Interactive simulation system for artificial ventilation on the internet: virtual ventilator.

PubMed

Takeuchi, Akihiro; Abe, Tadashi; Hirose, Minoru; Kamioka, Koichi; Hamada, Atsushi; Ikeda, Noriaki

2004-12-01

To develop an interactive simulation system "virtual ventilator" that demonstrates the dynamics of pressure and flow in the respiratory system under the combination of spontaneous breathing, ventilation modes, and ventilator options. The simulation system was designed to be used by unexperienced health care professionals as a self-training tool. The system consists of a simulation controller and three modules: respiratory, spontaneous breath, and ventilator. The respiratory module models the respiratory system by three resistances representing the main airway, the right and left lungs, and two compliances also representing the right and left lungs. The spontaneous breath module generates inspiratory negative pressure produced by a patient. The ventilator module generates driving force of pressure or flow according to the combination of the ventilation mode and options. These forces are given to the respiratory module through the simulation controller. The simulation system was developed using HTML, VBScript (3000 lines, 100 kB) and ActiveX control (120 kB), and runs on Internet Explorer (5.5 or higher). The spontaneous breath is defined by a frequency, amplitude and inspiratory patterns in the spontaneous breath module. The user can construct a ventilation mode by setting a control variable, phase variables (trigger, limit, and cycle), and options. Available ventilation modes are: controlled mechanical ventilation (CMV), continuous positive airway pressure, synchronized intermittent mandatory ventilation (SIMV), pressure support ventilation (PSV), SIMV + PSV, pressure-controlled ventilation (PCV), pressure-regulated volume control (PRVC), proportional assisted ventilation, mandatory minute ventilation (MMV), bilevel positive airway pressure (BiPAP). The simulation system demonstrates in a graph and animation the airway pressure, flow, and volume of the respiratory system during mechanical ventilation both with and without spontaneous breathing. We developed a web application that demonstrated the respiratory mechanics and the basic theory of ventilation mode.

Depression May Reduce Adherence during CPAP Titration Trial

PubMed Central

Law, Mandy; Naughton, Matthew; Ho, Sally; Roebuck, Teanau; Dabscheck, Eli

2014-01-01

Study Objectives: Depression is a risk factor for medication non-compliance. We aimed to identify if depression is associated with poorer adherence during home-based autotitrating continuous positive airway pressure (autoPAP) titration. Design: Mixed retrospective-observational study. Setting: Academic center. Participants: Two-hundred forty continuous positive airway pressure-naïve obstructive sleep apnea (OSA) patients. Measurements: Patients underwent approximately 1 week of home-based autoPAP titration with adherence data downloaded from the device. Electronic hospital records were reviewed in a consecutive manner for inclusion. Three areas of potential predictors were examined: (i) demographics and clinical factors, (ii) disease severity, and (iii) device-related variables. Depression and anxiety were assessed using the Hospital Anxiety and Depression Scale (HADS). Scores on the subscales were categorized as normal or clinical diagnoses of depression (≥ 8) and anxiety (≥ 11). The primary outcome variable was the mean hours of autoPAP used per night. Results: Patients were diagnosed with OSA by either attended polysomnography (n = 73, AHI 25.5[15.1-41.5]) or unattended home oximetry (n = 167, ODI3 34.0[22.4-57.4]) and had home-based autoPAP titration over 6.2 ± 1.2 nights. Mean autoPAP use was 4.5 ± 2.4 hours per night. Multiple linear regression analysis revealed that depression and lower 95th percentile pressures significantly predicted lesser hours of autoPAP use (R2 = 0.19, p < 0.001). Significantly milder OSA in those requiring lower pressures may have confounded the relationship between 95th percentile pressure and autoPAP use. Conclusion: Depression was independently associated with poorer adherence during home-based autoPAP titration. Depression may be a potential target for clinicians and future research aimed at enhancing adherence to autoPAP therapy. Citation: Law M; Naughton M; Ho S; Roebuck T; Dabscheck E. Depression may reduce adherence during CPAP titration trial. J Clin Sleep Med 2014;10(2):163-169. PMID:24532999

Solid Lubricants for Space Structures

DTIC Science & Technology

1993-04-17

will utilize mechanically interlocked hardware (caged bearings or bearings for ultra precision gimbals pointing mechanisms) controlled through precision...structure unless the lubricant were of low vapor pressure and/or suitably sealed to I prevent molecular effusion . While temperatures within spacecraft or...incorporation in the continuous cast system. The die made of graphite, consists of a plurality of openings or holes located in the die and positioned (unlined

Efficacy and Safety of Adjunctive Modafinil Treatment on Residual Excessive Daytime Sleepiness among Nasal Continuous Positive Airway Pressure-Treated Japanese Patients with Obstructive Sleep Apnea Syndrome: A Double-Blind Placebo-Controlled Study

PubMed Central

Inoue, Yuichi; Takasaki, Yuji; Yamashiro, Yoshihiro

2013-01-01

Study Objectives: This double-blind study evaluated the efficacy and safety of modafinil for treating excessive daytime sleepiness in Japanese patients with obstructive sleep apnea syndrome (OSAS). Methods: Patients with residual excessive sleepiness (Epworth Sleepiness Scale [ESS] ≥ 11) on optimal nasal continuous positive airway pressure (nCPAP) therapy (apnea-hypopnea index ≤ 10) were randomized to either 200 mg modafinil (n = 52) or placebo (n = 62) once daily for 4 weeks. Outcomes included baseline-week 4 changes in ESS total score, sleep latency on maintenance of wakefulness test (SL-MWT), nocturnal polysomnography, Pittsburgh Sleep Quality Index (PSQI), and safety. Results: All 114 randomized patients completed the study. Mean change in ESS total score (-6.6 vs -2.4, p < 0.001) and SL-MWT (+2.8 vs -0.4 minutes, p = 0.009) were significantly greater with modafinil than with placebo. ESS total score decreased from > 11 to < 11 at the final assessment in 69.2% of modafinil-treated patients and 30.6% of placebo-treated patients (p < 0.001). Corresponding rates at week 1 were 57.7% and 33.9% (p = 0.014). Changes in nocturnal polysomnography, PSQI, and apnea-hypopnea index from baseline to the final assessment were similar in both groups. Adverse drug reactions occurred in 36.5% and 22.6% of patients in the modafinil and placebo groups, respectively (p = 0.146). Conclusions: Once-daily modafinil was effective and well tolerated for managing residual daytime sleepiness in Japanese OSAS patients with residual excessive daytime sleepiness on optimal nCPAP therapy. Clinical Trial Registration: JapicCTI-No.090777 Citation: Inoue Y; Takasaki Y; Yamashiro Y. Efficacy and safety of adjunctive modafinil treatment on residual excessive daytime sleepiness among nasal continuous positive airway pressure-treated Japanese patients with obstructive sleep apnea syndrome: a double-blind placebo-controlled study. J Clin Sleep Med 2013;9(8):751-757. PMID:23946704

Nasal masks or binasal prongs for delivering continuous positive airway pressure in preterm neonates-a randomised trial.

PubMed

Chandrasekaran, Aparna; Thukral, Anu; Jeeva Sankar, M; Agarwal, Ramesh; Paul, Vinod K; Deorari, Ashok K

2017-03-01

The objective of this study was to compare the efficacy and safety of continuous positive airway pressure (CPAP) delivered using nasal masks with binasal prongs. We randomly allocated 72 neonates between 26 and 32 weeks gestation to receive bubble CPAP by either nasal mask (n = 37) or short binasal prongs (n = 35). Primary outcome was mean FiO 2 requirement at 6, 12 and 24 h of CPAP initiation and the area under curve (AUC) of FiO 2 against time during the first 24 h (FiO 2 AUC 0-24 ). Secondary outcomes were the incidence of CPAP failure and nasal trauma. FiO 2 requirement at 6, 12 and 24 h (mean (SD); 25 (5.8) vs. 27.9 (8); 23.8 (4.5) vs. 25.4 (6.8) and 22.6 (6.8) vs. 22.7 (3.3)) as well as FiO 2 AUC 0-24 (584.0 (117.8) vs. 610.6 (123.6)) were similar between the groups. There was no difference in the incidence of CPAP failure (14 vs. 20%; relative risk 0.67; 95% confidence interval 0.24-1.93). Incidence of severe nasal trauma was lower with the use of nasal masks (0 vs. 31%; p < .001). Nasal masks appear to be as efficacious as binasal prongs in providing CPAP. Masks are associated with lower risk of severe nasal trauma. CTRI2012/08/002868 What is Known? • Binasal prongs are better than single nasal and nasopharyngeal prongs for delivering continuous positive airway pressure (CPAP) in preventing need for re-intubation. • It is unclear if they are superior to newer generation nasal masks in preterm neonates requiring CPAP. What is New? • Oxygen requirement during the first 24 h of CPAP delivery is comparable with use of nasal masks and binasal prongs. • Use of nasal masks is, however, associated with significantly lower risk of severe grades of nasal injury.

Does personality play a role in continuous positive airway pressure compliance?

PubMed Central

Maschauer, Emily L.; Fairley, Donna M.

2017-01-01

Key points Continuous positive airway pressure (CPAP) adherence is low among individuals with obstructive sleep apnoea. Type D personality and high scores on the depression and hypochondriasis scales on the Minnesota Multiphasic Personality Inventory (MMPI) have been identified as factors contributing to non-compliance with CPAP. Further research into personality type may assist in understanding why some people adhere to CPAP, while others fail. Obstructive sleep apnoea (OSA) is a condition characterised by repetitive, intermittent partial or complete collapse/obstruction of the upper airway during sleep. Continuous positive airway pressure (CPAP) is highly efficacious in treating OSA but its effectiveness is limited due to suboptimal acceptance and adherence rates, with as many as 50% of OSA patients discontinuing CPAP treatment within the first year. Until recently, research has focused on examining mechanistic and demographic factors that could explain nonadherence (e.g. age, sex, race and education level) with limited applicability in a prospective or clinical manner. More recent research has focused on personality factors or types of patients with OSA who comply and do not comply with CPAP adherence in an attempt to enhance the accuracy of predicting treatment compliance. Type D personality has been found to be prevalent in one third of patients with OSA. The presence of Type D personality increases noncompliance and poor treatment outcomes due to negative affectivity, social inhibition, unhealthy lifestyle, and a reluctance to consult and/or follow medical advice. Conversely, individuals who are more likely to adhere to CPAP treatment tend to have a high internal locus of control and high self-efficacy, self-refer for treatment, and have active coping skills. By assessing personality and coping skills, the clinician may gain insight into the likelihood of a patient’s adherence to treatment. If the patient displays potential risk factors for CPAP noncompliance, the clinician can offer the patient education, refer them to a support group, engage in behavioural/motivational therapy and undertake regular follow-up visits or phone calls incorporating troubleshooting to increase CPAP adherence, especially in individuals with Type D personality. PMID:28289449

Sleep Apnea Related Risk of Motor Vehicle Accidents is Reduced by Continuous Positive Airway Pressure: Swedish Traffic Accident Registry Data

PubMed Central

Karimi, Mahssa; Hedner, Jan; Häbel, Henrike; Nerman, Olle; Grote, Ludger

2015-01-01

Study Objectives: Obstructive sleep apnea (OSA) is associated with an increased risk of motor vehicle accidents (MVAs). The rate of MVAs in patients suspected of having OSA was determined and the effect of continuous positive airway pressure (CPAP) was investigated. Design: MVA rate in patients referred for OSA was compared to the rate in the general population using data from the Swedish Traffic Accident Registry (STRADA), stratified for age and calendar year. The risk factors for MVAs, using demographic and polygraphy data, and MVA rate before and after CPAP were evaluated in the patient group. Setting: Clinical sleep laboratory and population based control (n = 635,786). Patients: There were 1,478 patients, male sex 70.4%, mean age 53.6 (12.8) y. Interventions: CPAP. Measurements and Results: The number of accidents (n = 74) among patients was compared with the expected number (n = 30) from a control population (STRADA). An increased MVA risk ratio of 2.45 was found among patients compared with controls (P < 0.001). Estimated excess accident risk was most prominent in the elderly patients (65–80 y, seven versus two MVAs). In patients, driving distance (km/y), EDS (Epworth Sleepiness score ≥ 16), short habitual sleep time (≤ 5 h/night), and use of hypnotics were associated with increased MVA risk (odds ratios 1.2, 2.1, 2.7 and 2.1, all P ≤ 0.03). CPAP use ≥ 4 h/night was associated with a reduction of MVA incidence (7.6 to 2.5 accidents/1,000 drivers/y). Conclusions: The motor vehicle accident risk in this large cohort of unselected patients with obstructive sleep apnea suggests a need for accurate tools to identify individuals at risk. Sleep apnea severity (e.g., apnea-hypopnea index) failed to identify patients at risk. Citation: Karimi M, Hedner J, Häbel H, Nerman O, Grote L. Sleep apnea related risk of motor vehicle accidents is reduced by continuous positive airway pressure: Swedish traffic accident registry data. SLEEP 2015;38(3):341–349. PMID:25325460

Obstructive sleep apnoea/hypopnoea syndrome in adults with Down syndrome

PubMed Central

2016-01-01

Key points Adults with Down syndrome are predisposed to obstructive sleep apnoea/hypopnoea syndrome (OSAHS) due to overlap between the Down syndrome phenotype and OSAHS risk factors. The prevalence of OSAHS in adults with Down syndrome is estimated at 35–42%. This is up to ten-times higher than in the general adult population. Symptoms of OSAHS, including behavioural and emotional disturbances as well as standard symptoms such as sleepiness, should be monitored as part of regular health surveillance in adults with Down syndrome. There is evidence that the use of continuous positive airway pressure (CPAP) therapy in adults with Down syndrome and comorbid OSAHS can lead to significant improvements in subjective sleepiness, behaviour and cognitive function, though further large-scale trials are required. Educational aims To discuss the relationship between the phenotypic features of Down syndrome and the risk factors for obstructive sleep apnoea/hypopnoea syndrome (OSAHS). To examine the prevalence of OSAHS in adults with Down syndrome. To review recent research into the effectiveness of treatment of OSAHS in adults with Down syndrome using continuous positive airway pressure (CPAP) therapy. Obstructive sleep apnoea/hypopnoea syndrome (OSAHS) is characterised by repeated cycles of upper airway obstruction during sleep, leading to diurnal symptoms. Individuals with Down syndrome are predisposed to OSAHS due to overlap between the Down syndrome phenotype and OSAHS risk factors. Recent large studies using subjective and objective measures estimate that OSAHS affects around 40% of adults with Down syndrome, in contrast to 2–4% of the general adult population. The “double-hit” of comorbid Down syndrome and OSAHS may accelerate cognitive decline in adults with Down syndrome. However, with the appropriate care and support, OSAHS can be treated effectively in this group using continuous positive airway pressure (CPAP) therapy, improving daytime function and behaviour. Symptoms of OSAHS should be routinely monitored in this population, with testing and treatment available to all adults with Down syndrome; however, this is not currently commonplace, and health inequalities are evident. PMID:28270865

Is the Relationship between Race and Continuous Positive Airway Pressure Adherence Mediated by Sleep Duration?

PubMed Central

Billings, Martha E.; Rosen, Carol L.; Wang, Rui; Auckley, Dennis; Benca, Ruth; Foldvary-Schaefer, Nancy; Iber, Conrad; Zee, Phyllis; Redline, Susan; Kapur, Vishesh K.

2013-01-01

Study Objectives: Black race has been associated with decreased continuous positive airway pressure (CPAP) adherence. Short sleep duration, long sleep latency, and insomnia complaints may affect CPAP adherence as they affect sleep and opportunity to use CPAP. We assessed whether self-reported sleep measures were associated with CPAP adherence and if racial variations in these sleep characteristics may explain racial differences in CPAP adherence. Design: Analysis of data from a randomized controlled trial (HomePAP), which investigated home versus laboratory-based diagnosis and treatment of obstructive sleep apnea. Setting: Seven American Academy of Sleep Medicine-accredited sleep centers in five cities in the United States. Patients or Participants: Enrolled subjects (n = 191) with apnea-hypopnea index ≥ 15 and sleepiness (Epworth Sleepiness Scale > 12). Interventions: N/A. Measurements and Results: Multivariable regression was used to assess if subjective sleep measures and symptoms predicted 3-mo CPAP use. Mediation analysis was used to assess if sleep measures mediated the association of race with CPAP adherence. Black participants reported shorter sleep duration and longer sleep latency at baseline than white and Hispanic participants. Shorter sleep duration and longer sleep latency predicted worse CPAP adherence. Sleep duration mediated the association of black race with lower CPAP adherence. However, insomnia symptoms were not associated with race or CPAP adherence. Conclusions: Among subjects with similar severity of obstructive sleep apnea and sleepiness, baseline self-reported sleep duration and latency, but not perceived insomnia, predicted CPAP adherence over 3 mo. Sleep duration explains some of the observed differences in CPAP use by race. Sleep duration and latency should be considered when evaluating poor CPAP adherence. Clinical Trial Information: Portable Monitoring for Diagnosis and Management of Sleep Apnea (HomePAP) URL: http://clinicaltrials.gov/show/NCT00642486. NIH clinical trials registry number: NCT00642486. Citation: Billings ME; Rosen CL; Wang R; Auckley D; Benca R; Foldvary-Schaefer N; Iber C; Zee P; Redline S; Kapur VK. Is the relationship between race and continuous positive airway pressure adherence mediated by sleep duration? SLEEP 2013;36(2):221-227. PMID:23372269

Effects of Heated Humidification and Topical Steroids on Compliance, Nasal Symptoms, and Quality of Life in Patients with Obstructive Sleep Apnea Syndrome Using Nasal Continuous Positive Airway Pressure

PubMed Central

Ryan, Silke; Doherty, Liam S.; Nolan, Geraldine M.; McNicholas, Walter T.

2009-01-01

Background: Nasal side effects are common in patients with obstructive sleep apnea syndrome (OSAS) starting on nasal continuous positive airway pressure (CPAP) therapy. We tested the hypothesis that heated humidification or nasal topical steroids improve compliance, nasal side effects and quality of life in this patient group. Methods: 125 patients with the established diagnosis of OSAS (apnea/hypopnea index ≥ 10/h), who tolerated CPAP via a nasal mask, and who had a successful CPAP titration were randomized to 4 weeks of dry CPAP, humidified CPAP or CPAP with additional topical nasal steroid application (fluticasone, GlaxoWellcome). Groups were similar in all demographic variables and in frequency of nasal symptoms at baseline. Outcome measures were objective compliance, quality of life (short form 36), subjective sleepiness (Epworth Sleepiness Scale score) and nasal symptoms such as runny, dry or blocked nose, sneezing and headaches; all variables assessed using a validated questionnaire and by direct interview. Results: There was no difference in compliance between groups after 4 weeks (dry: 5.21 ± 1.66 h/night, fluticasone: 5.66 ± 1.68, humidifier: 5.21 ± 1.84; p = 0.444). Quality of life and subjective sleepiness improved in all groups, but there were no differences in the extent of improvement. Nasal Symptoms were less frequently reported in the humidifier group (28%) than in the remaining groups (dry: 70%, fluticasone: 53%, p = 0.002). However, the addition of fluticasone resulted in increased frequency of sneezing. Conclusion: The addition of a humidifier, but not nasal steroids decreases the frequency of nasal symptoms in unselected OSAS patients initiating CPAP therapy; however compliance and quality of life remain unaltered. Citation: Ryan S; Doherty LS; Nolan GM; McNicholas WT. Effects of heated humidification and topical steroids on compliance, nasal symptoms, and quality of life in patients with obstructive sleep apnea syndrome using nasal continuous positive airway pressure. J Clin Sleep Med 2009;5(5):422-427. PMID:19961025

Effects of positive end-expiratory pressure on brain tissue oxygen pressure of severe traumatic brain injury patients with acute respiratory distress syndrome: A pilot study.

PubMed

Nemer, Sérgio Nogueira; Caldeira, Jefferson B; Santos, Ricardo G; Guimarães, Bruno L; Garcia, João Márcio; Prado, Darwin; Silva, Ricardo T; Azeredo, Leandro M; Faria, Eduardo R; Souza, Paulo Cesar P

2015-12-01

To verify whether high positive end-expiratory pressure levels can increase brain tissue oxygen pressure, and also their effects on pulse oxygen saturation, intracranial pressure, and cerebral perfusion pressure. Twenty traumatic brain injury patients with acute respiratory distress syndrome were submitted to positive end-expiratory pressure levels of 5, 10, and 15 cm H2O progressively. The 3 positive end-expiratory pressure levels were used during 20 minutes for each one, whereas brain tissue oxygen pressure, oxygen saturation, intracranial pressure, and cerebral perfusion pressure were recorded. Brain tissue oxygen pressure and oxygen saturation increased significantly with increasing positive end-expiratory pressure from 5 to 10 and from 10 to 15 cm H2O (P=.0001 and P=.0001 respectively). Intracranial pressure and cerebral perfusion pressure did not differ significantly with increasing positive end-expiratory pressure from 5 to 10 and from 10 to 15 cm H2O (P=.16 and P=.79 respectively). High positive end-expiratory pressure levels increased brain tissue oxygen pressure and oxygen saturation, without increase in intracranial pressure or decrease in cerebral perfusion pressure. High positive end-expiratory pressure levels can be used in severe traumatic brain injury patients with acute respiratory distress syndrome as a safe alternative to improve brain oxygenation. Copyright © 2015 Elsevier Inc. All rights reserved.

The long-term health plan and disability cost benefit of obstructive sleep apnea treatment in a commercial motor vehicle driver population.

PubMed

Hoffman, Benjamin; Wingenbach, Dustin D; Kagey, Amy N; Schaneman, Justin L; Kasper, David

2010-05-01

To assess the impact on health plan and disability costs associated with continuous positive airway pressure or bi-level positive airway pressure treatment of obstructive sleep apnea in a commercial motor vehicle driver population. A retrospective, pre/post claims-based comparison analysis was performed. Health plan and disability costs, in addition to disability claimant rates and missed workdays were compared for the 12 months before treatment to the 24 months after treatment. Health plan costs were significantly lower in both the first and second years after treatment. Short-term disability metrics also exhibited favorable results, with approximately half as many using the benefit, lower costs, and fewer missed workdays in the postperiod. Effective treatment of obstructive sleep apnea in drivers is associated with lower health care and disability costs and fewer missed workdays.

Highly stable aerosol generator

DOEpatents

DeFord, H.S.; Clark, M.L.

1981-11-03

An improved compressed air nebulizer has been developed such that a uniform aerosol particle size and concentration may be produced over long time periods. This result is achieved by applying a vacuum pressure to the makeup assembly and by use of a vent tube between the atmosphere and the makeup solution. By applying appropriate vacuum pressures to the makeup solution container and by proper positioning of the vent tube, a constant level of aspirating solution may be maintained within the aspirating assembly with aspirating solution continuously replaced from the makeup solution supply. This device may also be adapted to have a plurality of aerosol generators and only one central makeup assembly. 2 figs.

Highly stable aerosol generator

DOEpatents

DeFord, Henry S.; Clark, Mark L.

1981-01-01

An improved compressed air nebulizer has been developed such that a uniform aerosol particle size and concentration may be produced over long time periods. This result is achieved by applying a vacuum pressure to the makeup assembly and by use of a vent tube between the atmosphere and the makeup solution. By applying appropriate vacuum pressures to the makeup solution container and by proper positioning of the vent tube, a constant level of aspirating solution may be maintained within the aspirating assembly with aspirating solution continuously replaced from the makeup solution supply. This device may also be adapted to have a plurality of aerosol generators and only one central makeup assembly.

Gasdynamic Inlet Isolation in Rotating Detonation Engine

DTIC Science & Technology

2010-12-01

2D Total Variation Diminishing (TVD): Continuous Riemann Solver Minimum Dissipation: LHS & RHS Activate pressure switch : Supersonic Activate...Total Variation Diminishing (TVD) limiter: Continuous Riemann Solver Minimum Dissipation: LHS & RHS Activate pressure switch : Supersonic Activate...Continuous 94 Riemann Solver Minimum Dissipation: LHS & RHS Activate pressure switch : Supersonic Activate pressure gradient switch: Normal

Non-invasive measurements of pulse pressure variation and stroke volume variation in anesthetized patients using the Nexfin blood pressure monitor.

PubMed

Stens, Jurre; Oeben, Jeroen; Van Dusseldorp, Ab A; Boer, Christa

2016-10-01

Nexfin beat-to-beat arterial blood pressure monitoring enables continuous assessment of hemodynamic indices like cardiac index (CI), pulse pressure variation (PPV) and stroke volume variation (SVV) in the perioperative setting. In this study we investigated whether Nexfin adequately reflects alterations in these hemodynamic parameters during a provoked fluid shift in anesthetized and mechanically ventilated patients. The study included 54 patients undergoing non-thoracic surgery with positive pressure mechanical ventilation. The provoked fluid shift comprised 15° Trendelenburg positioning, and fluid responsiveness was defined as a concomitant increase in stroke volume (SV) >10 %. Nexfin blood pressure measurements were performed during supine steady state, Trendelenburg and supine repositioning. Hemodynamic parameters included arterial blood pressure (MAP), CI, PPV and SVV. Trendelenburg positioning did not affect MAP or CI, but induced a decrease in PPV and SVV by 3.3 ± 2.8 and 3.4 ± 2.7 %, respectively. PPV and SVV returned back to baseline values after repositioning of the patient to baseline. Bland-Altman analysis of SVV and PPV showed a bias of -0.3 ± 3.0 % with limits of agreement ranging from -5.6 to 6.2 %. The SVV was more superior in predicting fluid responsiveness (AUC 0.728) than the PVV (AUC 0.636), respectively. The median bias between PPV and SVV was different for patients younger [-1.5 % (-3 to 0)] or older [+2 % (0-4.75)] than 55 years (P < 0.001), while there were no gender differences in the bias between PPV and SVV. The Nexfin monitor adequately reflects alterations in PPV and SVV during a provoked fluid shift, but the level of agreement between PPV and SVV was low. The SVV tended to be superior over PPV or Eadyn in predicting fluid responsiveness in our population.

A historical perspective on ventilator management.

PubMed

Shapiro, B A

1994-02-01

Paralysis via neuromuscular blockade in ICU patients requires mechanical ventilation. This review historically addresses the technological advances and scientific information upon which ventilatory management concepts are based, with special emphasis on the influence such concepts have had on the use of neuromuscular blocking agents. Specific reference is made to the scientific information and technological advances leading to the newer concepts of ventilatory management. Information from > 100 major studies in the peer-reviewed medical literature, along with the author's 25 yrs of clinical experience and academic involvement in acute respiratory care is presented. Nomenclature related to ventilatory management is specifically defined and consistently utilized to present and interpret the data. Pre-1970 ventilatory management is traced from the clinically unacceptable pressure-limited devices to the reliable performance of volume-limited ventilators. The scientific data and rationale that led to the concept of relatively large tidal volume delivery are reviewed in the light of today's concerns regarding alveolar overdistention, control-mode dyssynchrony, and auto-positive end-expiratory pressure. Also presented are the post-1970 scientific rationales for continuous positive airway pressure/positive end-expiratory pressure therapy, avoidance of alveolar hyperxia, and partial ventilatory support techniques (intermittent mandatory ventilation/synchronized intermittent mandatory ventilation). The development of pressure-support devices is discussed and the capability of pressure-control techniques is presented. The rationale for more recent concepts of total ventilatory support to avoid ventilator-induced lung injury is presented. The traditional techniques utilizing volume-preset ventilators with relatively large tidal volumes remain valid and desirable for the vast majority of patients requiring mechanical ventilation. Neuromuscular blockade is best avoided in these patients. However, adequate analgesia, amnesia, and sedation are required. For patients with severe lung disease, alveolar overdistention and hyperoxia should be avoided and may be best accomplished by total ventilatory support techniques, such as pressure control. Total ventilatory support requires neuromuscular blockade and may not provide eucapnic ventilation.

Social pressure, coercion, and client engagement at treatment entry: a self-determination theory perspective.

PubMed

Wild, T Cameron; Cunningham, John A; Ryan, Richard M

2006-10-01

Research on coercion in addiction treatment typically investigates objective sources of social pressure among legally mandated clients. Little research has examined the impact of clients' perceptions of social pressures in generalist addiction services. Clients seeking substance abuse treatment (N=300; 221 males and 79 females; M age=36.6 years) rated the extent to which treatment was being sought because of coercive social pressures (external motivation; alpha=.89), guilt about continued substance abuse (introjected motivation; alpha=.84), or a personal choice and commitment to the goals of the program (identified motivation; alpha=.85). External treatment motivation was positively correlated with legal referral, social network pressures to enter treatment, and was inversely related to problem severity. In contrast, identified treatment motivation was positively correlated with self-referral and problem severity, and was inversely related to perceived coercion (ps<.05). Hierarchical multiple regression analyses showed that referral source (i.e., mandated treatment status), legal history, and social network pressures did not predict any of 6 measures of client engagement at the time treatment was sought. However, treatment motivation variables accounted for unique variance in these outcomes when added to each model (DeltaR(2)s=.06-.23, ps<.05). Specifically, identified treatment motivation predicted perceived benefits of reducing substance use, attempts to reduce drinking and drug use, as well as self (and therapist) ratings of interest in the upcoming treatment episode (betas=.18-.31, ps<.05). Results suggest that the presence of legal referral and/or social network pressures to quit, cut down, and/or enter treatment does not affect client engagement at treatment entry.

Efficacy of a pressure-sensing mattress cover system for reducing interface pressure: study protocol for a randomized controlled trial.

PubMed

Wong, Holly; Kaufman, Jaime; Baylis, Barry; Conly, John M; Hogan, David B; Stelfox, Henry T; Southern, Danielle A; Ghali, William A; Ho, Chester H

2015-09-29

Interface pressure is a key risk factor in the development of pressure ulcers. Visual feedback of continuous interface pressure between the body and support surface could inform clinicians on repositioning strategies and play a key role in an overall strategy for the prevention and management of pressure ulcers. A parallel two-group randomized controlled clinical trial will be conducted to study the effect of continuous pressure imaging on reducing interface pressure and on the incidence of pressure ulcers in vulnerable hospital patients. A total of 678 eligible consenting inpatients at risk of pressure ulcer development in a tertiary acute care institution will be randomly allocated to either having the ForeSite PT™ system with the liquid-crystal display monitor turned on to provide visual feedback to the clinicians while also collecting continuous interface pressure data (intervention group) or to having the ForeSite PT™ system with monitor turned off (that is, not providing visual feedback) but still collecting continuous interface pressure data (control group), in a ratio of 1:1. Continuous interface pressure data will be collected in both groups for 3 days (72 h). Data collection will continue until discharge for a subset of approximately 60 patients. The primary outcome will be the differences in the two groups' interface pressure analysis. Interface pressure readings will be collected through hourly samplings of continuous interface pressure recordings. Secondary outcomes will be the differences between the two groups in pressure-related skin and soft tissue changes in areas at risk of pressure ulcer (obtained at baseline within 24 h of admission) and on the third day of the trial or at discharge and perceptions of the intervention by patients and clinicians (obtained on the third day or at discharge). This will be the first randomized controlled trial to investigate the effect of visual feedback with continuous interface pressure of vulnerable hospital patients across different care settings, and the association between interface pressure and development of pressure-related skin and soft tissue changes. The results could provide important information to guide clinical practice in the prevention and management of pressure ulcers. ClinicalTrials.gov NCT02325388 (date of registration: 24 December 2014).

[Development of a continuous blood pressure monitoring and recording system].

PubMed

Zhang, Yang; Li, Yong; Gao, Shumei; Song, Yilin

2012-09-01

A small experimental system is constructed with working principle of continuous blood pressure monitoring based on the volume compensation method. The preliminary experimental results show that the system can collect blood pressure signals at the radial artery effectively. The digital PID algorithm can track the variation of blood pressure. And the accuracy of continuous blood pressure detecting achieve the level of same kind of product.

Pressure-volume relationships and elastance in the knee joint of the dog.

PubMed

Nade, S; Newbold, P J

1984-12-01

This study has investigated changes in intra-articular hydrostatic pressure in the knee joints of normal dogs in response to continuous and stepwise infusions of fluids. The relationship between pressure and volume in the joint was examined over the pressure range of -8 to +50 mmHg, and also at much higher pressures often associated with joint disease or injury. The effects of joint angle and dog weight on the pressure-volume relationship and on elastance of the dogs' knees were also examined. With liquid paraffin B.P. the pressure was found to increase more with each unit volume infused at subatmospheric pressures than at pressures around atmospheric, and increased more again at higher pressures. The pressure-volume curve with saline infusions was affected by egress of fluid from the joint at supra-atmospheric pressure. Above +5 mmHg the rise in pressure per unit volume infused was less than that for paraffin at the same volume. Elastance and compliance of the normal joint capsule were calculated from the pressure-volume data. Elastance was high at subatmospheric pressures, decreased rapidly as atmospheric pressure was approached and rose as a linear function of pressure above 12 mmHg. The biphasic shape of the elastance-pressure curve is discussed, and explanations for the shape are suggested. After intra-articular pressure in the knee was raised by infusion of paraffin oil the joint was moved through the range of positions from 125 deg extension to 50 deg flexion. Intra-articular pressure did not change across the range 125-110 deg. However, increasing the angle of flexion from 110 to 50 deg resulted in a rise in pressure which became steeper for each volume increment. Increasing intra-articular fluid volume caused a decrease in the total range of movement of the joint. The pressure-volume curves measured at extended angles of 110, 125 and 140 deg, where the starting pressures were subatmospheric, were the same. At flexed joint positions of 80 and 50 deg, where the starting pressures were supra-atmospheric, the pressure-volume curves became steeper with greater flexion. Elastance of the joint tissues increased with flexion. The elastance at each joint angle depended also on the volume or pressure. Significant differences were found to exist between pressure-volume curves for three groups of animals of different weight.(ABSTRACT TRUNCATED AT 400 WORDS)

Sleep continuity is positively correlated with sleep duration in laboratory nighttime sleep recordings

PubMed Central

Van Dongen, Hans P. A.; Natelson, Benjamin H.; Bender, Amy M.; Palombini, Luciana O.; Bittencourt, Lia; Tufik, Sergio; Ayappa, Indu; Rapoport, David M.

2017-01-01

Sleep duration varies widely across individuals and appears to be trait-like. Differences in the stability of underlying sleep processes may underlie this phenomenon. To investigate underlying mechanisms, we examined the relationship between sleep duration and sleep continuity in baseline polysomnography (PSG) recordings from three independently collected datasets: 1) 134 healthy controls (ages 37 ± 13 years) from the São Paulo Epidemiologic Sleep Study, who spent one night in a sleep laboratory, 2) 21 obstructive sleep apnea (OSA) patients who were treated with continuous positive airway pressure for at least 2 months (45 ± 12 years, respiratory disturbance index <15), who spent one night in a sleep laboratory with previous experience of multiple PSG studies, and 3) 62 healthy controls (28 ± 6 years) who, as part of larger experiments, spent 2 consecutive nights in a sleep laboratory. For each dataset, we used total sleep time (TST) to separate subjects into those with shorter sleep (S-TST) and those with longer sleep (L-TST). In all three datasets, survival curves of continuous sleep segments showed greater sleep continuity in L-TST than in S-TST. Correlation analyses with TST as a continuous variable corroborated the results; and the results also held true after controlling for age. There were no significant differences in baseline waking performance and sleepiness between S-TST and L-TST. In conclusion, in both healthy controls and treated OSA patients, sleep continuity was positively correlated with sleep duration. These findings suggest that S-TST may differ from L-TST in processes underlying sleep continuity, shedding new light on mechanisms underlying individual differences in sleep duration. PMID:28394943

Prevention of Hypoxemia During Apnea Testing: A Comparison of Oxygen Insufflation And Continuous Positive Airway Pressure.

PubMed

Kramer, Andreas H; Couillard, Philippe; Bader, Ryan; Dhillon, Peter; Kutsogiannis, Demetrios J; Doig, Christopher J

2017-08-01

Apnea testing is an essential step in the clinical diagnosis of brain death. Current international guidelines recommend placement of an oxygen (O 2 ) insufflation catheter into the endotracheal tube to prevent hypoxemia, but use of a continuous positive airway pressure (CPAP) valve may be more effective at limiting arterial partial pressure of O 2 (PO 2 ) reduction. We performed a multicenter study assessing consecutive apnea tests in 14 intensive care units (ICUs) in two cities utilizing differing protocols. In one city, O 2 catheters are placed and arterial blood gases (ABGs) performed at intervals determined by the attending physician. In the other city, a resuscitation bag with CPAP valve is attached to the endotracheal tube, and ABGs performed every 3-5 min. We assessed arterial PO 2 , partial pressure of carbon dioxide (PCO 2 ), pH, and blood pressure at the beginning and termination of each apnea test. Thirty-six apnea tests were performed using an O 2 catheter and 50 with a CPAP valve. One test per group was aborted because of physiological instability. There were no significant differences in the degree of PO 2 reduction (-59 vs. -32 mmHg, p = 0.72), rate of PCO 2 rise (3.2 vs. 3.9 mmHg per min, p = 0.22), or pH decline (-0.02 vs. -0.03 per min, p = 0.06). Performance of ABGs at regular intervals was associated with shorter test duration (10 vs. 7 min, p < 0.0001), smaller PCO 2 rise (30 vs. 26 mmHg, p = 0.0007), and less pH reduction (-0.20 vs. -0.17, p = 0.0012). Lower pH at completion of the apnea test was associated with greater blood pressure decline (p = 0.006). Both methods of O 2 supplementation are associated with similar changes in arterial PO 2 and PCO 2 . Performance of ABGs at regular intervals shortens apnea test duration and may avoid excessive pH reduction and consequent hemodynamic effects.

Effect of continuous negative-pressure breathing on skin blood flow during exercise in a hot environment.

PubMed

Nagashima, K; Nose, H; Takamata, A; Morimoto, T

1998-06-01

To assess the impact of continuous negative-pressure breathing (CNPB) on the regulation of skin blood flow, we measured forearm blood flow (FBF) by venous-occlusion plethysmography and laser-Doppler flow (LDF) at the anterior chest during exercise in a hot environment (ambient temperature = 30 degreesC, relative humidity = approximately 30%). Seven male subjects exercised in the upright position at an intensity of 60% peak oxygen consumption rate for 40 min with and without CNPB after 20 min of exercise. The esophageal temperature (Tes) in both conditions increased to 38.1 degreesC by the end of exercise, without any significant differences between the two trials. Mean arterial pressure (MAP) increased by approximately 15 mmHg by 8 min of exercise, without any significant difference between the two trials before CNPB. However, CNPB reduced MAP by approximately 10 mmHg after 24 min of exercise (P < 0.05). The increase in FBF and LDF in the control condition leveled off after 18 min of exercise above a Tes of 37.7 degreesC, whereas in the CNPB trial the increase continued, with a rise in Tes despite the decrease in MAP. These results suggest that CNPB enhances vasodilation of skin above a Tes of approximately 38 degrees C by stretching intrathoracic baroreceptors such as cardiopulmonary baroreceptors.

Posture changes and subfoveal choroidal blood flow.

PubMed

Longo, Antonio; Geiser, Martial H; Riva, Charles E

2004-02-01

To evaluate the effect of posture change on subfoveal choroidal blood flow (ChBF) in normal volunteers. The pulsatile, nonpulsatile, and mean ChBF were measured with laser Doppler flowmetry in 11 healthy volunteers with a mean age of 32 +/- 13 (SD) years. The posture of the subjects was changed from standing (90 degrees ), to supine (-8 degrees ), and back to standing, with a mechanically driven table. During the whole experimental procedure, ChBF and heart rate (HR) were continuously recorded. After 30 seconds in standing position, the subjects were tilted to supine during approximately 30 seconds. They remained in this position for approximately 2 minutes, after which they were tilted back to the standing position (recovery), where they remained for another approximately 2 minutes. Systemic brachial artery blood pressure (BP) was measured in the baseline, supine, and recovery positions. This procedure was repeated to measure the intraocular pressure (IOP) at the different postures. Mean BP did not change significantly throughout the experimental procedure. As the body was tilted from standing to supine, HR decreased by 16% (P < 0.0004), IOP increased by 29% (P < 0.001), and mean ChBF increased by 11% (P < 0.01). The increase in ChBF was primarily due to an increase in the nonpulsatile component of the blood velocity. Based on previously reported experimental data that indicate that the ocular perfusion pressure increases less than predicted by purely hydrostatic considerations when the body is tilted from the standing to the supine position, the observed increase in ChBF suggests a passive response of the choroidal circulation to the posture change.

Factors affecting the decision to be treated with continuous positive airway pressure for obstructive sleep apnea syndrome.

PubMed

Tzischinsky, Orna; Shahrabani, Shosh; Peled, Ron

2011-07-01

Obstructive sleep apnea syndrome (OSAS) is a sleep-related breathing disorder characterized by excessive daytime sleepiness, accidents and high medical expenses. The first line of treatment for OSAS is continuous positive airway pressure (CPAP). To examine attitudes and beliefs as well as physiological and sociodemographic factors affecting OSA patients' decision whether or not to purchase a CPAP device. The study was divided into two stages; in the first, 83 subjects completed self-administered questionnaires prior to sleep examination (polysomnography, PSG). The questionnaires related to sleep habits, sleep disorders, questions organized around health belief model (HBM) concepts, sociodemographic information, health status and PSG examination. In the second stage, 3 months later, 50 OSAS patients were interviewed by telephone, which included questions about their reasons for purchasing/not purchasing the CPAP device. Only 48% of the OSAS patients purchased the CPAP device. The significant factors positively affecting the decision included higher levels of physiological factors such as body mass index (coefficient 0.36, P < 0.05) and respiratory disturbance index (coefficient 0.16, P < 0.05), higher income levels (coefficient 3.26, P < 0.05), and higher levels of knowledge about OSAS (coefficient -2.98, P < 0.1). Individuals who are more aware of their own health condition, are better informed about OSAS and have higher incomes are more likely to purchase the device. We suggest reducing the level of co-payment and providing patients with more information about the severe effects of OSAS.

Value and limitations of transpulmonary pressure calculations during intra-abdominal hypertension.

PubMed

Cortes-Puentes, Gustavo A; Gard, Kenneth E; Adams, Alexander B; Faltesek, Katherine A; Anderson, Christopher P; Dries, David J; Marini, John J

2013-08-01

To clarify the effect of progressively increasing intra-abdominal pressure on esophageal pressure, transpulmonary pressure, and functional residual capacity. Controlled application of increased intra-abdominal pressure at two positive end-expiratory pressure levels (1 and 10 cm H2O) in an anesthetized porcine model of controlled ventilation. Large animal laboratory of a university-affiliated hospital. Eleven deeply anesthetized swine (weight 46.2 ± 6.2 kg). Air-regulated intra-abdominal hypertension (0-25 mm Hg). Esophageal pressure, tidal compliance, bladder pressure, and end-expiratory lung aeration by gas dilution. Functional residual capacity was significantly reduced by increasing intra-abdominal pressure at both positive end-expiratory pressure levels (p ≤ 0.0001) without corresponding changes of end-expiratory esophageal pressure. Above intra-abdominal pressure 5 mm Hg, plateau airway pressure increased linearly by ~ 50% of the applied intra-abdominal pressure value, associated with commensurate changes of esophageal pressure. With tidal volume held constant, negligible changes occurred in transpulmonary pressure due to intra-abdominal pressure. Driving pressures calculated from airway pressures alone (plateau airway pressure--positive end-expiratory pressure) did not equate to those computed from transpulmonary pressure (tidal changes in transpulmonary pressure). Increasing positive end-expiratory pressure shifted the predominantly negative end-expiratory transpulmonary pressure at positive end-expiratory pressure 1 cm H2O (mean -3.5 ± 0.4 cm H2O) into the positive range at positive end-expiratory pressure 10 cm H2O (mean 0.58 ± 1.2 cm H2O). Despite its insensitivity to changes in functional residual capacity, measuring transpulmonary pressure may be helpful in explaining how different levels of positive end-expiratory pressure influence recruitment and collapse during tidal ventilation in the presence of increased intra-abdominal pressure and in calculating true transpulmonary driving pressure (tidal changes of transpulmonary pressure). Traditional interpretations of respiratory mechanics based on unmodified airway pressure were misleading regarding lung behavior in this setting.

Treatment with continuous positive airway pressure may affect blood glucose levels in nondiabetic patients with obstructive sleep apnea syndrome.

PubMed

Czupryniak, Leszek; Loba, Jerzy; Pawlowski, Maciej; Nowak, Dariusz; Bialasiewicz, Piotr

2005-05-01

Obstructive sleep apnea syndrome (OSAS) is often associated with impaired glucose metabolism. Data on the effects of OSAS treatment with continuous positive airway pressure (CPAP) on blood glucose and insulin resistance are conflicting. The study aimed at assessing the immediate effect of CPAP on glucose control measured with a continuous glucose monitoring system (CGMS). Nine non-diabetes subjects with OSAS (mean age 53.0 +/- 8.0 years; body mass index 34.8 +/- 5.3 kg/m2) underwent 2 overnight polysomnographic examinations: a diagnostic study and one with CPAP treatment. Continuous glucose monitoring system (CGMS) was applied overnight on both occasions. Glucose metabolism was assessed with a 75-g oral glucose tolerance test, plasma insulin and homeostatic model assessment of insulin resistance (HOMA-IR) index. The mean (+/- SD) apnoea-hypopnea index (AHI) at diagnostic polysomnography was 54.3 +/- 29.3 (range 16-81). Fasting plasma insulin levels in patients with OSAS was 84.3 +/- 43.4 pM at baseline, and the HOMA-IR was 3.6 +/- 2.2. CPAP treatment in the subjects with OSAS resulted in a significant reduction in the AHI to 4.5 +/- 7.1. All of the major saturation parameters improved significantly on CPAP. CGMS showed mean glucose values significantly higher during the CPAP night than during the diagnostic night: 80 +/- 11 mg/dL versus 63 +/- 7 mg/dL (P < .01). Fasting insulin and HOMA-IR measured after the CPAP night tended to be higher than at baseline (98.4 +/- 51.0 pmol vs 84.3 +/- 43.4 pmol and 3.9 pmol +/- 2.6 vs 3.6 +/- 2.2 pmol, respectively, P > .05). CPAP treatment in nondiabetic obese patients with OSAS may have an immediate elevating effect on blood glucose.

Seismic Motion Stability, Measurement and Precision Control.

DTIC Science & Technology

1979-12-01

tiltmeter . Tilt was corrected by changing air pressure in one bank of isolators to maintain the reference tiltmeter at null well within the 0.1 arcsecond...frequency rotations (0-0.1 Hz), a high quality, two-axis tiltmeter is used. The azimuth orientation angle could be measured with a four-position gyro...compassing system with considerably less accuracy than the tiltmeters . However, it would provide a continuous automatic azimuth determination update every

Continuous Positive Airway Pressure Device Time to Procurement in a Disadvantaged Population.

PubMed

DelRosso, Lourdes M; Hoque, Romy; Chesson, Andrew L

2015-01-01

Introduction. The management of obstructive sleep apnea (OSA) in patients who cannot afford a continuous positive airway pressure (CPAP) device is challenging. In this study we compare time to CPAP procurement in three groups of patients diagnosed with OSA: uninsured subsidized by a humanitarian grant (Group 1), uninsured unsubsidized (Group 2), and those with Medicare or Medicaid (Group 3). We evaluate follow-up and adherence in Group 1. We hypothesize that additional factors, rather than just the ability to obtain CPAP, may uniquely affect follow-up and adherence in uninsured patients. Methods. 30 patients were in Groups 1 and 2, respectively. 12 patients were in Group 3. Time of CPAP procurement from OSA diagnosis to CPAP initiation was assessed in all groups. CPAP adherence data was collected for Group 1 patients at 1, 3, 6, and 9 months. Results. There were no significant differences between groups in gender, age, body mass index, or apnea hypopnea index. The mean time to procurement in Group 1 was shorter compared to Group 2 but not significant. Compared to both Group 1 and Group 2, Group 3 patients had significantly shorter times to device procurement. Conclusion. Time to procurement of CPAP was significantly shorter in those with Medicaid/Medicare insurance compared to the uninsured.

Compliance with and effectiveness of adaptive servoventilation versus continuous positive airway pressure in the treatment of Cheyne‐Stokes respiration in heart failure over a six month period

PubMed Central

Philippe, C; Stoïca‐Herman, M; Drouot, X; Raffestin, B; Escourrou, P; Hittinger, L; Michel, P‐L; Rouault, S; d'Ortho, M‐P

2006-01-01

Objective To compare compliance with and effectiveness of adaptive servoventilation (ASV) versus continuous positive airway pressure (CPAP) in patients with the central sleep apnoea syndrome (CSA) with Cheyne‐Stokes respiration (CSR) and with congestive heart failure in terms of the apnoea–hypopnoea index (AHI), quality of life, and left ventricular ejection fraction (LVEF) over six months. Methods 25 patients (age 28–80 years, New York Heart Association (NYHA) class II–IV) with stable congestive heart failure and CSA‐CSR were randomly assigned to either CPAP or ASV. At inclusion, both groups were comparable for NYHA class, LVEF, medical treatment, body mass index, and CSA‐CSR. Results Both ASV and CPAP decreased the AHI but, noticeably, only ASV completely corrected CSA‐CSR, with AHI below 10/h. At three months, compliance was comparable between ASV and CPAP; however, at six months compliance with CPAP was significantly less than with ASV. At six months, the improvement in quality of life was higher with ASV and only ASV induced a significant increase in LVEF. Conclusion These results suggest that patients with CSA‐CSR may receive greater benefit from treatment with ASV than with CPAP. PMID:15964943

Increased airway reactivity in a neonatal mouse model of Continuous Positive Airway Pressure (CPAP)

PubMed Central

Mayer, Catherine A.; Martin, Richard J.; MacFarlane, Peter M.

2015-01-01

Background Continuous positive airway pressure (CPAP) is a primary form of respiratory support used in the intensive care of preterm infants, but its long-term effects on airway (AW) function are unknown. Methods We developed a neonatal mouse model of CPAP treatment to determine whether it modifies later AW reactivity. Un-anesthetized spontaneously breathing mice were fitted with a mask to deliver CPAP (6cmH2O, 3hrs/day) for 7 consecutive days starting at postnatal day 1. Airway reactivity to methacholine was assessed using the in vitro living lung slice preparation. Results One week of CPAP increased AW responsiveness to methacholine in male, but not female mice, compared to untreated control animals. The AW hyper-reactivity of male mice persisted for 2 weeks (at P21) after CPAP treatment ended. 4 days of CPAP, however, did not significantly increase AW reactivity. Females also exhibited AW hyper-reactivity at P21, suggesting a delayed response to early (7 days) CPAP treatment. The effects of 7 days of CPAP on hyper-reactivity to methacholine were unique to smaller AWs whereas larger ones were relatively unaffected. Conclusion These data may be important to our understanding of the potential long-term consequences of neonatal CPAP therapy used in the intensive care of preterm infants. PMID:25950451

Continuous Positive Airway Pressure versus Mechanical Ventilation on the Fist Day of Life in Very Low-Birth-Weight Infants

PubMed Central

Flannery, Dustin D.; O’Donnell, Elizabeth; Kornhauser, Mike; Dysart, Kevin; Greenspan, Jay; Aghai, Zubair H.

2017-01-01

Objective The objective of this study was to determine differences in the incidence of bronchopulmonary dysplasia (BPD) or death in very low-birth-weight (VLBW) infants managed successfully on continuous positive airway pressure (CPAP) versus mechanical ventilation on the first day of life (DOL). Study Design This is a retrospective analysis of the Alere neonatal database for infants born between January 2009 and December 2014, weighing ≤ 1,500 g. Baseline demographics, clinical characteristics, and outcomes were compared between the two groups. Multivariate regression analysis was performed to control the variables that differ in bivariate analysis. Results In this study, 4,629 infants (birth weight 1,034 ± 290 g, gestational age 28.1 ± 2.5 weeks) met the inclusion criteria. The successful use of early CPAP was associated with a significant reduction in BPD or death (p < 0.001), as well as days to room air, decreased oxygen use at discharge, lower risk for severe intraventricular hemorrhage, and patent ductus arteriosus requiring surgical ligation (p < 0.001 for all outcomes). Conclusion Successful use of early CPAP on the first DOL in VLBW infants is associated with a reduced risk of BPD or death. PMID:27057767

Influence of mouth opening on oropharyngeal humidification and temperature in a bench model of neonatal continuous positive airway pressure.

PubMed

Fischer, Hendrik S; Ullrich, Tim L; Bührer, Christoph; Czernik, Christoph; Schmalisch, Gerd

2017-02-01

Clinical studies show that non-invasive respiratory support by continuous positive airway pressure (CPAP) affects gas conditioning in the upper airways, especially in the presence of mouth leaks. Using a new bench model of neonatal CPAP, we investigated the influence of mouth opening on oropharyngeal temperature and humidity. The model features the insertion of a heated humidifier between an active model lung and an oropharyngeal head model to simulate the recurrent expiration of heated, humidified air. During unsupported breathing, physiological temperature and humidity were attained inside the model oropharynx, and mouth opening had no significant effect on oropharyngeal temperature and humidity. During binasal CPAP, the impact of mouth opening was investigated using three different scenarios: no conditioning in the CPAP circuit, heating only, and heated humidification. Mouth opening had a strong negative impact on oropharyngeal humidification in all tested scenarios, but heated humidification in the CPAP circuit maintained clinically acceptable humidity levels regardless of closed or open mouths. The model can be used to test new equipment for use with CPAP, and to investigate the effects of other methods of non-invasive respiratory support on gas conditioning in the presence of leaks. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Factors supporting dentist leaders' retention in leadership.

PubMed

Tuononen, T; Lammintakanen, J; Suominen, A L

2017-12-01

The aim was to study factors associated with staying in a dentist leadership position. We used an electronic questionnaire to gather data from 156 current or former Finnish dentist leaders in 2014. Principal component analysis categorized statements regarding time usage and opportunities in managerial work into five main components. Associations between these main component scores and the tendency to stay as a leader were analyzed with logistic regression. Out of the five main components, two were significantly associated with staying as a leader: 'career intentions', which represented intent to continue or to leave the leadership position; and 'work time control opportunities', which represented how leaders could control their own work time. Other factors that supported staying were leadership education, more work time available for leadership work, and lower age. The main component 'work pressure' decreased, although not significantly, the odds of continuing; it included lack of leadership work time, and pressure from superiors or subordinates. Leaders have important roles in health care, ensuring everyday operations as well as developing their organizations to meet future challenges. Knowledge of these supporting factors will enable dentist leaders and their organizations to improve working conditions in order to recruit and retain motivated and competent persons. In addition, well-designed education is important to inspire and encourage future leaders. Copyright© 2017 Dennis Barber Ltd.

Change in frequency of periodic limb movements during sleep with usage of continuous positive airway pressure in obstructive sleep apnea syndrome.

PubMed

Aritake-Okada, Sayaka; Namba, Kazuyoshi; Hidano, Natsuki; Asaoka, Shoichi; Komada, Yoko; Usui, Akira; Matsuura, Masato; Inoue, Yuichi

2012-06-15

Periodic limb movements during sleep (PLMS) sometimes newly appear on the night of continuous positive airway pressure (CPAP) titration in patients with obstructive sleep apnea syndrome (OSAS). To ascertain the incidence and causative factors of this phenomenon, we investigated differences in its prevalence and the factors associated with newly appeared and persistent PLMS on CPAP titration night. We retrospectively analyzed polysomnographic data of 997 consecutive OSAS outpatients who had undergone overnight CPAP titration. On the basis of changes in periodic limb movements index (PLMI) values (cut off level≥15/h) from baseline polysomnography (BPSG) to CPAP titration PSG, patients were assigned to one of four groups: persistent, CPAP-emergent, CPAP-disappeared, and non-PLMS. The rate of patients was 6.7% in the persistent group, 8.0% in the CPAP-emergent group, 4.0% in the CPAP-disappearance group, and 81.2% in the non-PLMS group. Multivariate logistic regression analysis revealed that a higher apnea-hypopnea index (AHI) on BPSG and ≥47years of age appeared to be associated with the CPAP-emergent group. The results suggest that elderly patients with higher AHI at BPSG may present with CPAP-emergent PLMS. Copyright © 2012. Published by Elsevier B.V.

Continuous-flow cardiac assistance: effects on aortic valve function in a mock loop.

PubMed

Tuzun, Egemen; Rutten, Marcel; Dat, Marco; van de Vosse, Frans; Kadipasaoglu, Cihan; de Mol, Bas

2011-12-01

As the use of left ventricular assist devices (LVADs) to treat end-stage heart failure has become more widespread, leaflet fusion--with resul-tant aortic regurgitation--has been observed more frequently. To quantitatively assess the effects of nonpulsatile flow on aortic valve function, we tested a continuous-flow LVAD in a mock circulatory system (MCS) with an interposed valve. To mimic the hemodynamic characteristics of LVAD patients, we utilized an MCS in which a Jarvik 2000 LVAD was positioned at the base of a servomotor-operated piston pump (left ventricular chamber). We operated the LVAD at 8000 to 12,000 rpm, changing the speed in 1000-rpm increments. At each speed, we first varied the outflow resistance at a constant stroke volume, then varied the stroke volume at a constant outflow resistance. We measured the left ventricular pressure, aortic pressure, pump flow, and total flow, and used these values to compute the change, if any, in the aortic duty cycle (aortic valve open time) and transvalvular aortic pressure loads. Validation of the MCS was demonstrated by the simulation of physiologic pressure and flow waveforms. At increasing LVAD speeds, the mean aortic pressure load steadily increased, while the aortic duty cycle steadily decreased. Changes were consistent for each MCS experimental setting, despite variations in stroke volume and outflow resistance. Increased LVAD flow results in an impaired aortic valve-open time due to a pressure overload above the aortic valve. Such an overload may initiate structural changes, causing aortic leaflet fusion and/or regurgitation. Copyright © 2011 Elsevier Inc. All rights reserved.

The obese patient undergoing nonbariatric surgery.

PubMed

Bluth, Thomas; Pelosi, Paolo; de Abreu, Marcelo Gama

2016-06-01

This article provides the reader with recent findings on the pathophysiology of comorbidities in the obese, as well as evidence-based treatment options to deal with perioperative respiratory challenges. Our understanding of obesity-associated asthma, obstructive sleep apnea, and obesity hypoventilation syndrome is still expanding. Routine screening for obstructive sleep apnea using the STOP-Bang score might identify high-risk patients that benefit from perioperative continuous positive airway pressure and close postoperative monitoring. Measures to most effectively support respiratory function during induction of and emergence from anesthesia include optimal patient positioning and use of noninvasive positive pressure ventilation. Appropriate mechanical ventilation settings are under investigation, so that only the use of protective low tidal volumes could be currently recommended. A multimodal approach consisting of adjuvants, as well as regional anesthesia/analgesia techniques reduces the need for systemic opioids and related respiratory complications. Anesthesia of obese patients for nonbariatric surgical procedures requires knowledge of typical comorbidities and their respective treatment options. Apart from cardiovascular diseases associated with the metabolic syndrome, awareness of any pulmonary dysfunction is of paramount. A multimodal analgesia approach may be useful to reduce postoperative pulmonary complications.

Short term evaluation of respiratory effort by premature infants supported with bubble nasal continuous airway pressure using Seattle-PAP and a standard bubble device

PubMed Central

Welty, Stephen E.; Rusin, Craig G.; Stanberry, Larissa I.; Mandy, George T.; Gest, Alfred L.; Ford, Jeremy M.; Backes, Carl H.; Richardson, C. Peter; Howard, Christopher R.; Hansen, Thomas N.

2018-01-01

Background Almost one million prematurely born infants die annually from respiratory insufficiency, predominantly in countries with limited access to respiratory support for neonates. The primary hypothesis tested in the present study was that a modified device for bubble nasal continuous positive airway pressure (Bn-CPAP) would provide lower work of spontaneous breathing, estimated by esophageal pressure-rate products. Methods Infants born <32 weeks gestation and stable on Bn-CPAP with FiO2 <0.30 were studied within 72 h following delivery. Esophageal pressures during spontaneous breathing were measured during 2 h on standard Bn-CPAP, then 2 h with Bn-CPAP using a modified bubble device presently termed Seattle-PAP, which produces a different pattern of pressure fluctuations and which provided greater respiratory support in preclinical studies, then 2 h on standard Bn-CPAP. Results All 40 infants enrolled completed the study and follow-up through 36 wks post menstrual age or hospital discharge, whichever came first. No infants were on supplemental oxygen at completion of follow-up. No infants developed pneumothoraces or nasal trauma, and no adverse events attributed to the study were observed. Pressure-rate products on the two devices were not different, but effort of breathing, assessed by areas under esophageal pressure-time curves, was lower with Seattle-PAP than with standard Bn-CPAP. Conclusion Use of Seattle-PAP to implement Bn-CPAP lowers the effort of breathing exerted even by relatively healthy spontaneously breathing premature neonates. Whether the lower effort of breathing observed with Seattle-PAP translates to improvements in neonatal mortality or morbidity will need to be determined by studies in appropriate patient populations. PMID:29590143

Factors determining the level and changes in intra-articular pressure in the knee joint of the dog.

PubMed Central

Nade, S; Newbold, P J

1983-01-01

Intra-articular pressure levels were determined for joint positions throughout the normal physiological range of movement of dogs' knee joints. Change in joint position resulted in change in intra-articular pressure. It was demonstrated that intra-articular pressure is highest with the joint in the fully flexed position. Minimum pressure was recorded at a position between 80 degrees and 120 degrees. Minimum pressures were usually subatmospheric. The rate of change of joint position affected intra-articular pressure. The relationship of intra-articular pressure and joint position before and after full flexion demonstrated a hysteresis effect; the pressures were lower than for the same joint position before flexion. Maintenance of the joint in the fully flexed position for increasing periods of time between repeated movement cycles resulted in a similar reduction, of constant magnitude, in pressure between joint positions before and after each period of flexion. However, there was also a progressive decrease in pressure for all joint angles over the total number of movement cycles. There is a contribution to intra-articular pressure of joint capsular compliance and fluid movement into and out of the joint (both of which are time-dependent). The recording of intra-articular pressure in conscious, upright dogs revealed similar pressure levels to those measured in anaesthetized supine dogs. The major determinants of intra-articular pressure in normal dog knee joints include joint size, synovial fluid volume, position of joint, peri-articular tissue and joint anatomy, membrane permeability, capsular compliance, and movement of fluid into and out of the joint. Images Fig. 1 PMID:6875957

Role of positive ions in determining the deposition rate and film chemistry of continuous wave hexamethyl disiloxane plasmas.

PubMed

Michelmore, Andrew; Bryant, Paul M; Steele, David A; Vasilev, Krasimir; Bradley, James W; Short, Robert D

2011-10-04

New data shed light on the mechanisms of film growth from low power, low pressure plasmas of organic compounds. These data rebalance the widely held view that plasma polymer formation is due to radical/neutral reactions only and that ions play no direct role in contributing mass at the surface. Ion reactions are shown to play an important role in both the plasma phase and at the surface. The mass deposition rate and ion flux in continuous wave hexamethyl disiloxane (HMDSO) plasmas have been studied as a function of pressure and applied RF power. Both the deposition rate and ion flux were shown to increase with applied power; however, the deposition rate increased with pressure while the ion flux decreased. Positive ion mass spectrometry of the plasma phase demonstrates that the dominant ionic species is the (HMDSO-CH(3))(+) ion at m/z 147, but significant fragmentation and subsequent oligomerization was also observed. Chemical analysis of the deposits by X-ray photoelectron spectroscopy and secondary ion mass spectrometry show that the deposits were consistent with deposits reported by previous workers grown from plasma and hyperthermal (HMDSO-CH(3))(+) ions. Increasing coordination of silicon with oxygen in the plasma deposits reveals the role of ions in the growth of plasma polymers. Comparing the calculated film thicknesses after a fixed total fluence of 1.5 × 10(19) ions/m(2) to results for hyperthermal ions shows that ions can contribute significantly to the total absorbed mass in the deposits. © 2011 American Chemical Society

Higher levels of spontaneous breathing reduce lung injury in experimental moderate acute respiratory distress syndrome.

PubMed

Carvalho, Nadja C; Güldner, Andreas; Beda, Alessandro; Rentzsch, Ines; Uhlig, Christopher; Dittrich, Susanne; Spieth, Peter M; Wiedemann, Bärbel; Kasper, Michael; Koch, Thea; Richter, Torsten; Rocco, Patricia R; Pelosi, Paolo; de Abreu, Marcelo Gama

2014-11-01

To assess the effects of different levels of spontaneous breathing during biphasic positive airway pressure/airway pressure release ventilation on lung function and injury in an experimental model of moderate acute respiratory distress syndrome. Multiple-arm randomized experimental study. University hospital research facility. Thirty-six juvenile pigs. Pigs were anesthetized, intubated, and mechanically ventilated. Moderate acute respiratory distress syndrome was induced by repetitive saline lung lavage. Biphasic positive airway pressure/airway pressure release ventilation was conducted using the airway pressure release ventilation mode with an inspiratory/expiratory ratio of 1:1. Animals were randomly assigned to one of four levels of spontaneous breath in total minute ventilation (n = 9 per group, 6 hr each): 1) biphasic positive airway pressure/airway pressure release ventilation, 0%; 2) biphasic positive airway pressure/airway pressure release ventilation, > 0-30%; 3) biphasic positive airway pressure/airway pressure release ventilation, > 30-60%, and 4) biphasic positive airway pressure/airway pressure release ventilation, > 60%. The inspiratory effort measured by the esophageal pressure time product increased proportionally to the amount of spontaneous breath and was accompanied by improvements in oxygenation and respiratory system elastance. Compared with biphasic positive airway pressure/airway pressure release ventilation of 0%, biphasic positive airway pressure/airway pressure release ventilation more than 60% resulted in lowest venous admixture, as well as peak and mean airway and transpulmonary pressures, redistributed ventilation to dependent lung regions, reduced the cumulative diffuse alveolar damage score across lungs (median [interquartile range], 11 [3-40] vs 18 [2-69]; p < 0.05), and decreased the level of tumor necrosis factor-α in ventral lung tissue (median [interquartile range], 17.7 pg/mg [8.4-19.8] vs 34.5 pg/mg [29.9-42.7]; p < 0.05). Biphasic positive airway pressure/airway pressure release ventilation more than 0-30% and more than 30-60% showed a less consistent pattern of improvement in lung function, inflammation, and damage compared with biphasic positive airway pressure/airway pressure release ventilation more than 60%. In this model of moderate acute respiratory distress syndrome in pigs, biphasic positive airway pressure/airway pressure release ventilation with levels of spontaneous breath higher than usually seen in clinical practice, that is, more than 30% of total minute ventilation, reduced lung injury with improved respiratory function, as compared with protective controlled mechanical ventilation.

Implicit Incompressible SPH.

PubMed

Ihmsen, Markus; Cornelis, Jens; Solenthaler, Barbara; Horvath, Christopher; Teschner, Matthias

2013-07-25

We propose a novel formulation of the projection method for Smoothed Particle Hydrodynamics (SPH). We combine a symmetric SPH pressure force and an SPH discretization of the continuity equation to obtain a discretized form of the pressure Poisson equation (PPE). In contrast to previous projection schemes, our system does consider the actual computation of the pressure force. This incorporation improves the convergence rate of the solver. Furthermore, we propose to compute the density deviation based on velocities instead of positions as this formulation improves the robustness of the time-integration scheme. We show that our novel formulation outperforms previous projection schemes and state-of-the-art SPH methods. Large time steps and small density deviations of down to 0.01% can be handled in typical scenarios. The practical relevance of the approach is illustrated by scenarios with up to 40 million SPH particles.

Implicit incompressible SPH.

PubMed

Ihmsen, Markus; Cornelis, Jens; Solenthaler, Barbara; Horvath, Christopher; Teschner, Matthias

2014-03-01

We propose a novel formulation of the projection method for Smoothed Particle Hydrodynamics (SPH). We combine a symmetric SPH pressure force and an SPH discretization of the continuity equation to obtain a discretized form of the pressure Poisson equation (PPE). In contrast to previous projection schemes, our system does consider the actual computation of the pressure force. This incorporation improves the convergence rate of the solver. Furthermore, we propose to compute the density deviation based on velocities instead of positions as this formulation improves the robustness of the time-integration scheme. We show that our novel formulation outperforms previous projection schemes and state-of-the-art SPH methods. Large time steps and small density deviations of down to 0.01 percent can be handled in typical scenarios. The practical relevance of the approach is illustrated by scenarios with up to 40 million SPH particles.

Development and evaluation of a self-efficacy instrument for Japanese sleep apnea patients receiving continuous positive airway pressure treatment

PubMed Central

Saito, Ayako; Kojima, Shigeko; Sasaki, Fumihiko; Hayashi, Masamichi; Mieno, Yuki; Sakakibara, Hiroki; Hashimoto, Shuji

2015-01-01

The purpose of this study was to develop and evaluate a self-efficacy instrument for Japanese obstructive sleep apnea (OSA) patients treated with continuous positive airway pressure (CPAP). Analyzed subjects were 653 Japanese OSA patients (619 males and 34 females) treated with CPAP at a sleep laboratory in a respiratory clinic in a Japanese city. Based on Bandura’s social cognitive theory, the CPAP Self-Efficacy Questionnaire for Sleep Apnea in Japanese (CSESA-J) was developed by a focus group of experts, using a group interview of OSA patients for the items of two previous self-efficacy scales for Western sleep apnea patients receiving CPAP treatment. CSESA-J has two subscales, one for self-efficacy and the other for outcome expectancy, and consists of a total of 15 items. Content validity was confirmed by the focus group. Confirmatory factor analysis showed that the factor loadings of self-efficacy and outcome expectancy were 0.47–0.76 and 0.41–0.92, respectively, for the corresponding items. CSESA-J had a significant but weak positive association with the General Self-Efficacy Scale, and a strong positive association with “Self-efficacy scale on health behavior in patients with chronic disease.” Cronbach’s alpha coefficient was 0.85 for the self-efficacy subscale and 0.89 for the outcome expectancy subscale. The intraclass correlation coefficient using data from the first and second measurements with CSESA-J for a subset of 130 subjects was 0.93 for the self-efficacy and outcome expectancy subscales. These results support CSESA-J as a reliable and valid instrument for measuring the self-efficacy of Japanese OSA patients treated with CPAP. Further studies are warranted to confirm validity for female OSA patients and generalizability. PMID:25678832

Changes in Energy Metabolism after Continuous Positive Airway Pressure for Obstructive Sleep Apnea.

PubMed

Tachikawa, Ryo; Ikeda, Kaori; Minami, Takuma; Matsumoto, Takeshi; Hamada, Satoshi; Murase, Kimihiko; Tanizawa, Kiminobu; Inouchi, Morito; Oga, Toru; Akamizu, Takashi; Mishima, Michiaki; Chin, Kazuo

2016-09-15

Disrupted energy homeostasis in obstructive sleep apnea (OSA) may lead to weight gain. Paradoxically, treating OSA with continuous positive airway pressure (CPAP) may also promote weight gain, although the underlying mechanism remains unclear. To explore the underlying mechanism by which patients with OSA gain weight after CPAP. A comprehensive assessment of energy metabolism was performed in 63 newly diagnosed OSA study participants (51 men; 60.8 ± 10.1 yr; apnea-hypopnea index >20 h(-1)) at baseline, CPAP initiation, and at a 3-month follow-up. Measurements included polysomnography, body weight, body composition, basal metabolic rate (BMR), hormones (norepinephrine, cortisol, leptin, ghrelin, insulin-like growth factor-1), dietary intake, eating behavior, and physical activity. BMR significantly decreased after CPAP (1,584 kcal/d at baseline, 1,561 kcal/d at CPAP initiation, and 1,508 kcal/d at follow-up; P < 0.001), whereas physical activity and total caloric intake did not significantly change. In multivariate regression, baseline apnea-hypopnea index, Δurine norepinephrine, and CPAP adherence were significant predictors of ΔBMR. The weight gainers had higher leptin levels, lower ghrelin levels, and higher eating behavior scores than the non-weight gainers, indicating a positive energy balance and disordered eating behavior among the weight gainers. Among the parameters related to energy metabolism, increased caloric intake was a particularly significant predictor of weight gain. Although a reduction in BMR after CPAP predisposes to a positive energy balance, dietary intake and eating behavior had greater impacts on weight change. These findings highlight the importance of lifestyle modifications combined with CPAP. Clinical trial registered with http://www.umin.ac.jp/english/ (UMIN000012639).

Dynamics of Polydisperse Foam-like Emulsion

NASA Astrophysics Data System (ADS)

Hicock, Harry; Feitosa, Klebert

2011-10-01

Foam is a complex fluid whose relaxation properties are associated with the continuous diffusion of gas from small to large bubbles driven by differences in Laplace pressures. We study the dynamics of bubble rearrangements by tracking droplets of a clear, buoyantly neutral emulsion that coarsens like a foam. The droplets are imaged in three dimensions using confocal microscopy. Analysis of the images allows us to measure their positions and radii, and track their evolution in time. We find that the droplet size distribution fits a Weibull distribution characteristics of foam systems. Additionally, we observe that droplets undergo continuous evolution interspersed by occasional large rearrangements in par with local relaxation behavior typical of foams.

Pressurized tundish for controlling a continuous flow of molten metal

DOEpatents

Lewis, T.W.; Hamill, P.E. Jr.; Ozgu, M.R.; Padfield, R.C.; Rego, D.N.; Brita, G.P.

1990-07-24

A pressurized tundish for controlling a continuous flow of molten metal is characterized by having a pair of principal compartments, one being essentially unpressurized and receiving molten metal introduced thereto, and the other being adapted for maintaining a controlled gaseous pressure over the surface of the fluid metal therein, whereby, by controlling the pressure within the pressurized chamber, metal exiting from the tundish is made to flow continually and at a controlled rate. 1 fig.

Sleep in heart failure.

PubMed

Naughton, Matthew T; Lorenzi-Filho, Geraldo

2009-01-01

Sleep plays a large role in patients with heart failure. In normal subjects, sleep is usually in a supine position with reduced sympathetic drive, elevated vagal tone and as such a relatively lower cardiac output and minute ventilation, allowing for recuperation. Patients with heart failure may not experience the same degree of autonomic activity change and the supine position may place a large strain on the pulmonary system. More than half of all heart failure patients have one of two types of sleep apnea: either obstructive or central sleep apnea. Some patients have both types. Obstructive sleep apnea is likely to be a cause of heart failure due to large negative intrathoracic pressures, apnea related hypoxemia and hypercapnia, terminated by an arousal and surge in systemic blood pressure associated with endothelial damage and resultant premature atherosclerosis. Reversal of obstructive sleep apnea improves blood pressure, systolic contraction and autonomic dysfunction however mortality studies are lacking. Central sleep apnea with Cheyne Stokes pattern of respiration (CSA-CSR) occurs as a result of increased central controller (brainstem driving ventilation) and plant (ventilation driving CO2) gain in the setting of a delayed feed back (i.e., low cardiac output). It is thought this type of apnea is a result of moderately to severely impaired cardiac function and is possibly indicative of high mortality. Treatment of CSA-CSR is best undertaken by treating the underlying cardiac condition which may include with medications, pacemakers, transplantation or continuous positive airway pressure (CPAP). In such patients CPAP exerts unique effects to assist cardiac function and reduce pulmonary edema. Whether CPAP improves survival in this heart failure population remains to be determined.

A case of sleep apnea syndrome manifesting severe hypertension with high plasma norepinephrine levels.

PubMed

Makino, Shinya; Iwata, Masanobu; Fujiwara, Masayoshi; Ike, Shinpei; Tateyama, Hitone

2006-06-01

A 55-year-old female was admitted to our hospital with severe hypertension (274/140 mmHg). Endocrinological examination revealed that her plasma levels of norepinephrine (NE) was elevated with high levels of urinary NE, normetanephrine and vanillylmandelic acid (VMA), suggesting the presence of pheochromocytoma. However, neither computed tomography nor MIBG scintigraphy detected any catecholamine-producing tumor in or outside the adrenal glands. She was screened with full polysomnography because of heavy snoring, and the diagnosis of severe obstructive sleep apnea syndrome (OSAS) was made. She was treated with calcium channel blocker for three weeks, but severe hypertension persisted. After treatment with nasal continuous positive airway pressure (CPAP) was added, her blood pressure gradually lowered week by week. Concomitantly, the levels of plasma and urinary NE, urinary normetanephrine and urinary VMA were normalized following nasal CPAP therapy for 2 weeks. Additional treatments with alpha-adrenergic blocker further decreased her home blood pressure. After a year, she continued nasal CPAP therapy and her blood pressure was nearly below 160/100 mmHg. Urinary NE level was slightly above normal range and other catecholamines stayed within the normal range. This case shows that patients with OSAS could develop severe hypertension through elevated sympathetic tone, mimicking pheochromocytoma. Nasal CPAP therapy is recommended not only to improve hypertension and catecholamine excess but also to distinguish the condition from pheochromocytoma.

Theoretical Current-Voltage Curve in Low-Pressure Cesium Diode for Electron-Rich Emission

NASA Technical Reports Server (NTRS)

Coldstein, C. M.

1964-01-01

Although considerable interest has been shown in the space-charge analysis of low-pressure (collisionless case) thermionic diodes, there is a conspicuous lack in the presentation of results in a way that allows direct comparison with experiment. The current-voltage curve of this report was, therefore, computed for a typical case within the realm of experimental interest. The model employed in this computation is shown in Fig. 1 and is defined by the limiting potential distributions [curves (a) and (b)]. Curve (a) represents the potential V as a monotonic function of position with a slope of zero at the anode; curve (b) is similarly monotonic with a slope of zero at the cathode. It is assumed that by a continuous variation of the anode voltage, the potential distributions vary continuously from one limiting form to the other. Although solutions for infinitely spaced electrodes show that spatically oscillatory potential distributions may exist, they have been neglected in this computation.

Continuous positive airway pressure (CPAP) decreases pulmonary shunt in anaesthetized horses.

PubMed

Mosing, Martina; MacFarlane, Paul; Bardell, David; Lüthi, Laura; Cripps, Peter J; Bettschart-Wolfensberger, Regula

2016-11-01

To evaluate the effects of continuous positive airway pressure (CPAP) on intrapulmonary shunt, cardiac output and oxygen delivery in horses subjected to a 6 hour period of general anaesthesia. Randomized, experimental, crossover study. Ten healthy adult horses. Following medetomidine, diazepam and ketamine administration, orotracheal intubation was performed and horses positioned in dorsal recumbency. Anaesthesia was maintained with isoflurane carried in an oxygen and air mix (FiO 2 0.5) combined with a medetomidine infusion. Horses were anaesthetized twice and either CPAP (8 cmH 2 O) or physiologic airway pressure (NO CPAP) was applied to the lungs for 6 hours; the order of treatments was randomly assigned. Following induction of anaesthesia, cardiovascular and respiratory variables (including arterial blood gas analysis) were recorded every 30 minutes, cardiac output was measured every 60 minutes using the lithium dilution technique and oxygen delivery calculated. If PaCO 2 exceeded 100 mmHg (13.3 kPa), controlled ventilation was initiated and horses excluded from further data collection. Groups were compared using a general linear model. Data from eight horses were analysed. PaO 2 was 15-56 mmHg (2.00-7.45 kPa) higher (p < 0.001) and shunt fraction 6-14% lower (p < 0.001) in the CPAP group. No differences were seen for cardiac output and oxygen delivery. The lack of difference in oxygen delivery was attributed to lower haemoglobin levels in the CPAP group than in the NO CPAP group. CPAP of 8 cmH 2 O can be used in dorsally recumbent horses to decrease pulmonary shunt fraction without causing a decrease in cardiac output during longterm anaesthesia. © 2016 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.

Delivery room continuous positive airway pressure and early pneumothorax in term newborn infants.

PubMed

Clevenger, L; Britton, J R

2017-01-01

To assess the association between delivery room (DR) continuous positive airway pressure (CPAP) and pneumothorax (PT) in term newborns. Two studies performed in community hospitals used data extracted from computerized records of term newborns. Infants receiving positive pressure ventilation in the DR were excluded. Tabulated data included receipt of DR CPAP, PT on the day of birth, and gestational age (GA). In a case-control study from 2001-2013, infants with PT were compared to controls without PT but with respiratory distress or hypoxia persisting from birth for receipt of DR CPAP. In a cohort study from 2014-2016, infants receiving and not receiving DR CPAP were compared for the incidence of PT. In the case-control study, data were obtained for 169 cases and 850 controls. Compared to controls, PT infants were more likely to have received DR CPAP (16.8% vs. 40.2%, respectively, P < 0.001). Logistic regression revealed DR CPAP (Adjusted Odds Ratio [AOR] = 3.30, 95% confidence interval [CI] = 2.31, 4.72, P < 0.001) and GA (AOR = 1.21, 95% CI = 1.05, 1.39, P = 0.009) to be independent predictors of early PT.In the cohort study, PT was observed in 0.1% of 9255 control infants not receiving DR CPAP and 4.8% of 228 infants receiving DR CPAP (P < 0.001). In logistic regression analyses, DR CPAP significantly predicted PT (OR = 59.59, 95% CI = 23.34, 147.12, P < 0.001) and remained a significant predictor of PT after controlling for gestational age. Respiratory conditions treated with CPAP in delivery rooms are associated with increased risk of PT. A cause-and-effect relationship between CPAP and PT cannot be claimed in this study. Further research is needed to better understand this relationship.

Fixed but not autoadjusting positive airway pressure attenuates the time-dependent decline in glomerular filtration rate in patients with obstructive sleep apnea.

PubMed

Marrone, Oreste; Cibella, Fabio; Pépin, Jean-Louis; Grote, Ludger; Verbraecken, Johan; Saaresranta, Tarja; Kvamme, John A; Basoglu, Ozen K; Lombardi, Carolina; McNicholas, Walter T; Hedner, Jan; Bonsignore, Maria R

2018-04-23

The impact of treating obstructive sleep apnea (OSA) on renal function decline is controversial. Previous studies usually included small samples and did not consider specific effects of different continuous positive airway pressure (CPAP) modalities. The aim of this study was to evaluate the respective influence of fixed and auto-adjusting CPAP modes on estimated glomerular filtration rate (eGFR) in a large sample of patients derived from the prospective European Sleep Apnea Database (ESADA) cohort. In patients of the ESADA, eGFR before and after follow-up was calculated using the CKD-EPI equation. Three study groups were investigated, namely untreated patients (n=144), patients receiving fixed continuous positive airway pressure (fCPAP) (n=1,178), and patients on auto-adjusting CPAP (APAP) (n=485). In the whole sample, eGFR decreased over time. The rate of eGFR decline was significantly higher in the subgroup with eGFR above median [91.42 ml/min/1.73m 2 ] at baseline (p<0.0001 for effect of baseline eGFR). This decline was attenuated or absent (p<0.0001 for effect of treatment) in the subgroup of OSA treated by fCPAP. A follow-up duration exceeding the median (541 days), was associated with eGFR decline in the untreated and APAP groups, but not in the fCPAP group (p <0.0001 by two-way ANOVA for interaction between treatment and follow-up length). In multiple regression analysis, eGFR decline was accentuated by advanced age, female gender, cardiac failure, higher baseline eGFR and longer follow-up duration, while there was a protective effect of fCPAP. Fixed CPAP but not APAP, may prevent eGFR decline in OSA. Copyright © 2018 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

Molecular evolution of the enzymes involved in the sphingolipid metabolism of Leishmania: selection pressure in relation to functional divergence and conservation.

PubMed

Mandlik, Vineetha; Shinde, Sonali; Singh, Shailza

2014-06-21

Selection pressure governs the relative mutability and the conservedness of a protein across the protein family. Biomolecules (DNA, RNA and proteins) continuously evolve under the effect of evolutionary pressure that arises as a consequence of the host parasite interaction. IPCS (Inositol phosphorylceramide synthase), SPL (Sphingosine-1-P lyase) and SPT (Serine palmitoyl transferase) represent three important enzymes involved in the sphingolipid metabolism of Leishmania. These enzymes are responsible for maintaining the viability and infectivity of the parasite and have been classified as druggable targets in the parasite metabolome. The present work relates to the role of selection pressure deciding functional conservedness and divergence of the drug targets. IPCS and SPL protein families appear to diverge from the SPT family. The three protein families were largely under the influence of purifying selection and were moderately conserved baring two residues in the IPCS protein which were under the influence of positive selection. To further explore the selection pressure at the codon level, codon usage bias indices were calculated to analyze genes for their synonymous codon usage pattern. IPCS gene exhibited slightly lower codon bias as compared to SPL and SPT protein families. Evolutionary tracing of the proposed drug targets has been done with a viewpoint that the amino-acids lining the drug binding pocket should have a lower evolvability. Sites under positive selection (HIS20 and CYS30 of IPCS) should be avoided during devising strategies for inhibitor design.

Effects of a Short Course of Eszopiclone on Continuous Positive Airway Pressure Adherence

DTIC Science & Technology

2009-11-17

We collected addi- tional data related to mood and depression, libido and erectile dysfunction , and quality of life that will be in- cluded in...onset of therapy improves long-term CPAP adherence more than placebo in adults with obstructive sleep apnea. Design: Parallel randomized, placebo...collected. (ClinicalTrials.gov registration number: NCT00612157) Setting: Academic sleep disorder center. Patients: 160 adults (mean age, 45.7 years [SD

Blast-Induced Acceleration in a Shock Tube: Distinguishing Primary and Tertiary Blast Injury

DTIC Science & Technology

2016-10-01

objects of varied areal densities to define relations of blast flow conditions to acceleration and displacement , we have begun examination of the effects... displacement from other biomechanical components and effects of the shockwave. 15. SUBJECT TERMS Key words or phrases identifying major concepts in the...and total pressure, positive phase duration, and impulse) and acceleration and displacement of a wide range of inanimate objects, we have continued

Improved Pulse Transit Time Estimation by System Identification Analysis of Proximal and Distal Arterial Waveforms

DTIC Science & Technology

2011-10-01

response; pulse wave velocity ACCORDING TO THE MOENS-KORTEWEG equation, pulse wave ve- locity ( PWV ) increases as the arteries stiffen. Indeed, PWV is the...and mortality in hypertensive patients (2, 4, 12, 14). In addition, because arterial stiffness increases with arterial blood pressure (ABP), PWV and...ABP often show positive correlation, suggesting that PWV could provide a means to achieve continuous, noninvasive, and cuffless ABP monitoring (18

Mandibular Advancing Positive Pressure Apnea Remediation Device (MAPPARD)

DTIC Science & Technology

2014-06-01

inlet valve that will accept a 90-degree swivel and is tapered in the area where the lips intersect for better comfort . Further ergonomic testing will...production also informed the size of the necessary mouthpiece and the requirement for a design for a more ergonomic airway mouthpiece and tube connection...fit and ergonomics (see Figures. 32 and 33). The subsequent initial test showed that the model was comfortable and without aid of continuous air

Obstructive sleep apnea syndrome and hypertension: mechanism of the linkage and 24-h blood pressure control.

PubMed

Kario, Kazuomi

2009-07-01

Hypertensive patients with obstructive sleep apnea syndrome (OSAS) constitute a high-risk group for metabolic syndrome. OSAS directly induces negative intrathoracic pressure and decreases pulmonary stretch receptor stimulation, chemoreceptor stimulation, hypoxemia, hypercapnia and microarousal. These changes potentiate various risk factors, including the sympathetic nervous system, renin-angiotensin-aldosterone system and inflammation. Early detection and treatment of OSAS in asymptomatic hypertensive patients is essentially important to prevent hypertensive target organ damage and subsequent cardiovascular events. Continuous positive airway pressure (CPAP) therapy, a first-line treatment in hypertensive patients with moderate to severe OSAS, reduces ambulatory BP level, particularly during the sleep period, and midnight BP surge. However, individual differences in the BP-lowering effect of CPAP have been observed. OSAS hypertensive patients who do not tolerate CPAP remain at a high risk for cardiovascular disease because of negative intrathoracic pressure and need more aggressive antihypertensive treatment to achieve 24-h BP control with nocturnal BP <120/70 mm Hg.

[Obstructive sleep apnea syndrome, hypertension and artery].

PubMed

Baguet, Jean-Philippe; Barone-Rochette, Gilles; Pépin, Jean-Louis

2009-04-01

Obstructive sleep apnea syndrome (OSAS), due to upper airway collapse, is frequent but still underestimated. The dose-response relation between OSAS and hypertension (HTN) is now well established. Logically, therefore, blood pressure must be tested in every apneic patient, if necessary by ambulatory blood pressure monitoring. Multiple mechanisms explain this relation, most importantly the increase in sympathetic activity during apnea episodes. OSAS-related hypertension has several characteristics: it is highly prevalent, predominantly diastolic and nocturnal, and frequently affects non-dippers; and the HTN tends to be resistant to treatment. OSAS promotes the formation of arterial lesions (parietal thickening of the carotid artery, increased aortic stiffness, and endothelial dysfunction); the more severe the OSAS, the more severe the lesions. The beneficial effects on blood pressure of continuous positive airway pressure (CPAP), the benchmark treatment for OSAS, are still debated but appear to be significant for untreated or refractory hypertension, for severe OSAS, and when CPAP compliance is good. It also seems promising for the reduction of arterial lesions linked to OSAS.

Pro: Ambulatory blood pressure should be used in all patients on hemodialysis

PubMed Central

Agarwal, Rajiv

2015-01-01

In the adult population in general and among people with chronic kidney disease in particular, it is now well established that hypertension is a major driver of renal disease progression and cardiovascular morbidity and mortality [1–4]. Although the contribution of hypertension to cardiovascular morbidity and mortality among patients on long-term dialysis continues to be debated [5–8], a major barrier to detect hypertension as a risk factor for cardiovascular events in these patients has been the inability to diagnose hypertension [9]. Largely to blame has been the easy availability of pre-dialysis and post-dialysis blood pressure recordings in stark contrast to ambulatory blood pressure measurements in dialysis patients to accurately diagnose the presence or control of hypertension [10]. It is increasingly becoming clear that out-of-office blood pressure recordings are superior to clinic recordings in making a diagnosis, assessing target organ damage, evaluating prognosis and managing patients with hypertension [11–15]. In this debate, I have been asked to defend the position that ambulatory blood pressure recordings should be systematically applied to all patients on hemodialysis. PMID:26022728

Pressure injury prediction using diffusely scattered light

NASA Astrophysics Data System (ADS)

Diaz, David; Lafontant, Alec; Neidrauer, Michael; Weingarten, Michael S.; DiMaria-Ghalili, Rose Ann; Scruggs, Ericka; Rece, Julianne; Fried, Guy W.; Kuzmin, Vladimir L.; Zubkov, Leonid

2017-02-01

Pressure injuries (PIs) originate beneath the surface of the skin at the interface between bone and soft tissue. We used diffuse correlation spectroscopy (DCS) and diffuse near-infrared spectroscopy (DNIRS) to predict the development of PIs by measuring dermal and subcutaneous red cell motion and optical absorption and scattering properties in 11 spinal cord injury subjects with only nonbleachable redness in the sacrococcygeal area in a rehabilitation hospital and 20 healthy volunteers. A custom optical probe was developed to obtain continuous DCS and DNIRS data from sacrococcygeal tissue while the subjects were placed in supine and lateral positions to apply pressure from body weight and to release pressure, respectively. Rehabilitation patients were measured up to four times over a two-week period. Three rehabilitation patients developed open PIs (POs) within four weeks and eight patients did not (PNOs). Temporal correlation functions in the area of redness were significantly different (p<0.01) during both baseline and applied pressure stages for POs and PNOs. The results show that our optical method may be used for the early prediction of ulcer progression.

Early rescue administration of surfactant and nasal continuous positive airway pressure in preterm infants <32 weeks gestation.

PubMed

Tsakalidis, Christos; Kourti, Maria; Karagianni, Paraskevi; Rallis, Dimitris; Porpodi, Maria; Nikolaidis, Nikolaos

2011-08-01

This study reports our institutional experience on the outcome after prophylactic and early rescue endotracheal instillation of surfactant within 20 minutes of birth, followed by extubation and nasal continuous positive airway pressure (NCPAP) in preterm infants <32 weeks gestational age. A total of 142 infants were prospectively studied (42, gestational age from 23 to 27 and 100, from 28 up to 32 weeks). All infants were electively intubated for administration of 200 mg/kg porcine isolated surfactant (Curosurf, Chiesi Farmaceutici SPA, Parma, Italy) as soon as practicably possible (within 20 min after birth) and NCPAP was then initiated. Extubation and switch to NCPAP at 6 h was successful in 6/42 (14.3%) infants less than 28 weeks gestational age and 75/100 (75%) infants 28-32 weeks gestational age. Out of 81 infants that were successfully extubated, 76 (93.83%) never required re-ventilation. At 96 h of age, need for continuing intubation and ventilation was required by 6/38 (15.8%) alive infants <28 weeks gestational age and 8/100 (8%) infants 28-32 weeks gestational age. Mean duration of NCPAP post-extubation was 38±20 hours for infants 23-27 wks and 29±15 hours for infants 28-32 wks gestational age. The mortality rate was 2.81% (4/142). Implementation of prophylactic or early rescue administration of surfactant with NCPAP in infants at high risk for developing RDS in neonatal ICU is a safe modality of respiratory support in preterm infants.

Diastolic function of the nonfilling human left ventricle.

PubMed

Paulus, W J; Vantrimpont, P J; Rousseau, M F

1992-12-01

To investigate an early-diastolic left ventricular suction effect in humans, tip-micromanometer left ventricular pressure recordings were obtained in patients with mitral stenosis at the time of balloon inflations during percutaneous mitral valvuloplasty performed with a self-positioning Inoue balloon, which fits tightly in the mitral orifice. When mitral inflow was impeded in anesthetized dogs, left ventricular pressure decayed to a negative asymptote value. This negative asymptote value was consistent with an early diastolic suction effect. Tip-micromanometer left ventricular pressure recordings were obtained in 23 patients with symptomatic mitral stenosis at the time of balloon inflations during percutaneous mitral valvuloplasty performed with a self-positioning Inoue balloon. The left ventricular diastolic asymptote pressure (P(asy)) was determined in 47 nonfilling beats with a sufficiently long (greater than 200 ms) diastolic time interval (that is, the interval from minimal first derivative of left ventricular pressure to left ventricular end-diastolic pressure) and equaled 2 +/- 3 mm Hg for beats with normal intraventricular conduction and 3 +/- 2 mm Hg for beats with aberrant intraventricular conduction. Left ventricular angiography was performed in five patients during the first inflation of the Inoue balloon at the time of complete balloon expansion. Left ventricular end-diastolic volume of the nonfilling beats averaged 38 +/- 14 ml and was comparable to the left ventricular end-systolic volume (39 +/- 19 ml) measured during baseline angiography before mitral valvuloplasty. Time constants of left ventricular pressure decay were calculated on 21 nonfilling beats with a diastolic time interval greater than 200 ms, normal intraventricular conduction and peak left ventricular pressure greater than 50 mm Hg. Time constants (T0 and TBF) derived from an exponential curve fit with zero asymptote pressure and with a best-fit asymptote pressure were compared with a time constant (T(asy)) derived from an exponential curve fit with the measured diastolic left ventricular asymptote pressure. The value for T(asy) (37 +/- 9 ms) was significantly smaller than that for TBF (68 +/- 28 ms, p less than 0.001) and the value for the measured diastolic left ventricular asymptote pressure (2 +/- 4 mm Hg) was significantly larger than that for the best-fit asymptote pressure (-9 +/- 11 mm Hg, p less than 0.001). T0 (44 +/- 20 ms) was significantly (p less than 0.01) different from TBF but not from T(asy). During balloon inflation of a self-positioning Inoue balloon, left ventricular pressure decayed continuously toward a positive asymptote value and left ventricular cavity volume was comparable to the left ventricular end-systolic volume of filling beats. In these nonfilling beats, the best-fit asymptote pressure was unrelated to the measured asymptote pressure and T0 was a better measure of T(asy) than was TBF. Reduced internal myocardial restoring forces, caused by different extracellular matrix of the human heart, reduced external myocardial restoring forces caused by low coronary perfusion pressure during the balloon inflation and inward motion of the balloon-occluded mitral valve into the left ventricular cavity could explain the failure to observe significant diastolic left ventricular suction in the human heart.

The effect of continuous pressure monitoring on strategic shifting of medical inpatients at risk for PUs.

PubMed

Motamedi, S M; de Grood, J; Harman, S; Sargious, P; Baylis, B; Flemons, W; Ghali, W A

2012-11-01

To assess the impact of continuous pressure imaging technology on strategic turning of patients by health professionals. This pilot study of a newly-developed continuous pressure imaging technology (XSENSOR ForeSite PatientTurn System) involved two phases of videotaped observation of medical inpatients, with each patient serving as his/her own control: a control phase in which continuous pressure imaging was not available to health-care providers and an intervention phase where it was. The primary outcome was to determine whether access to the technology influenced the rate of patient turns/shifts by nursing staff. Secondary outcomes included a comparison of the rates of other care provider shifts, patient self-shifts, and family assisted shifts. Qualitative data regarding nurse and patient/family perspectives were also obtained. Complete control/intervention data were available for nine patients.The mean rate of two-person assisted turns was 0.274 +/- 0.087 turns per hour in the control phase versus 0.413 +/- 0.091 turns per hour in the intervention phase (p = 0.08). For the combined endpoint of two-person assisted turns or patient transfers off the bed into a wheelchair/chair, there was a statistically significant difference in the mean number of turns per hour: mean of 0.491 +/- 0.271 turns per hour for the intervention group versus 0.327 +/- 0.235 turns per hour for the control group (p = 0.04). Provider interviews confirmed that nurses used information from the technology to inform their patient shifting strategies and behaviours. This pilot study provides some initial data supporting the hypothesis that continuous pressure imaging technology could positively impact the frequency of patient turns by care providers, as well as provide impetus to inspect specific skin locations,thereby providing a potential targeted risk mitigation strategy for the development of pressure ulcers. Funding for the study was obtained from PreCarn Inc., an independent, nonprofit company supporting the pre-commercial development of new technologies, and from the Alberta Enterprise and Advanced Education (formally Alberta Advanced Education and Technology). The industry partner, XSENSOR, was involved in setup and maintenance of the technology, but was not involved in the evaluative research protocol. Specifically, XSENSOR personnel were not involved in the collection, coding, or analysis of outcome data, nor in the compilation and writing of this paper. None of the listed authors have any conflicts of interest, financial or otherwise, relating to the technology tested.

21 CFR 868.5965 - Positive end expiratory pressure breathing attachment.

Code of Federal Regulations, 2010 CFR

2010-04-01

... in a patient's lungs above atmospheric pressure at the end of exhalation. (b) Classification. Class... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Positive end expiratory pressure breathing... Positive end expiratory pressure breathing attachment. (a) Identification. A positive end expiratory...

The position of the arm during blood pressure measurement in sitting position.

PubMed

Adiyaman, Ahmet; Verhoeff, Rutger; Lenders, Jacques W M; Deinum, Jaap; Thien, Theo

2006-12-01

Determining the influence of the position of the arm on blood pressure measurement in the sitting position. Blood pressure of 128 individuals (the majority being treated hypertensive patients) visiting the outpatient clinic was measured simultaneously on both arms with arms in two different positions. First, both arms were placed at the chair support level and blood pressure was measured three times on both arms after 10 min of rest. Subsequently, while still remaining in the same sitting position, five blood pressure measurements were made simultaneously at both arms with one arm placed on the desk and one arm placed and supported at heart level (mid-sternal). The arm placed at heart level served as the reference arm. The choice of which arm was placed at desk level and which arm was placed at heart level was randomized. Both at desk level and at chair support level, mean (+/-SD) systolic and diastolic blood pressures were higher than blood pressure at heart level by 6.1/5.7+/-4.6/3.1 and 9.3/9.4+/-5.4/3.4 mmHg, respectively. The effect of the height differences between the arm positions on the blood pressure readings was smaller than predicted (0.49 mmHg/cm systolic and 0.47 mmHg/cm diastolic). No significant correlation was found between blood pressure difference in the different arm positions (desk and heart level) and age, sex, weight or baseline blood pressure. Different arm positions below heart level have significant effects on blood pressure readings. The leading guidelines about arm position during blood pressure measurement are not in accordance with the arm position used in the Framingham study, the most frequently used study for risk estimations.

Positioning bedridden patients to reduce interface pressures over the sacrum and great trochanter.

PubMed

Yoshikawa, Y; Maeshige, N; Sugimoto, M; Uemura, M; Noguchi, M; Terashi, H

2015-07-01

In this study, we evaluated the effect of hip-joint rotation on the interface pressure over the sacrum and greater trochanter with a new protocol for positioning of bedridden elderly patients. The interface pressure values over the sacrum and greater trochanter in bedridden patients were evaluated. These were collected in the supine position, 90° lateral position, and 30° and 40° laterally inclined positions with external rotation or neutral positioning of the hip joint. Each interface pressure was assessed with a device measuring pressure distribution, after which, the peak pressure index (PPI) was calculated. In the 17 patients examined, the PPI over the sacrum in the supine position was significantly greater than that in other positions. In the 30° and 40° laterally inclined positions, the PPIs over the greater trochanter were significantly lower in the neutral position of the hip joint compared with those in the external rotation position. Our findings revealed the effects of hip-joint rotation on the interface pressure for the greater trochanter, possibly due to the increased distance between the greater trochanter and the sacrum caused by neutral position of the hip joint. The results demonstrate that it is to best place the hip joint in a neutral position when the legs are in contact with the bed in order to distribute the pressure over the greater trochanter in the 30° and 40° laterally inclined positions. These results can be applied to the clinical setting to improve patient positioning and decrease pressure ulcers. The authors declare that they have no competing financial interests.

The effects of different lying positions on interface pressure, skin temperature, and tissue blood flow in nursing home residents.

PubMed

Källman, Ulrika; Engström, Maria; Bergstrand, Sara; Ek, Anna-Christina; Fredrikson, Mats; Lindberg, Lars-Göran; Lindgren, Margareta

2015-03-01

Although repositioning is considered an important intervention to prevent pressure ulcers, tissue response during loading in different lying positions has not been adequately explored. To compare the effects of different lying positions on interface pressure, skin temperature, and tissue blood flow in nursing home residents. From May 2011 to August 2012, interface pressure, skin temperature, and blood flow at three tissue depths were measured for 1 hr over the sacrum in 30° supine tilt and 0° supine positions and over the trochanter major in 30° lateral and 90° lateral positions in 25 residents aged 65 years or older. Measurement of interface pressure was accomplished using a pneumatic pressure transmitter connected to a digital manometer, skin temperature using a temperature sensor, and blood flow using photoplethysmography and laser Doppler flowmetry. Interface pressure was significantly higher in the 0° supine and 90° lateral positions than in 30° supine tilt and 30° lateral positions. The mean skin temperature increased from baseline in all positions. Blood flow was significantly higher in the 30° supine tilt position compared to the other positions. A hyperemic response in the post pressure period was seen at almost all tissue depths and positions. The 30° supine tilt position generated less interface pressure and allowed greater tissue perfusion, suggesting that this position is the most beneficial. © The Author(s) 2014.

Estimating sleep parameters using nasal pressure signals applicable to continuous positive airway pressure devices.

PubMed

Park, Jong-Uk; Erdenebayar, Urtnasan; Joo, Eun-Yeon; Lee, Kyoung-Joung

2017-06-27

This paper proposes a method for classifying sleep-wakefulness and estimating sleep parameters using nasal pressure signals applicable to a continuous positive airway pressure (CPAP) device. In order to classify the sleep-wakefulness states of patients with sleep-disordered breathing (SDB), apnea-hypopnea and snoring events are first detected. Epochs detected as SDB are classified as sleep, and time-domain- and frequency-domain-based features are extracted from the epochs that are detected as normal breathing. Subsequently, sleep-wakefulness is classified using a support vector machine (SVM) classifier in the normal breathing epoch. Finally, four sleep parameters-sleep onset, wake after sleep onset, total sleep time and sleep efficiency-are estimated based on the classified sleep-wakefulness. In order to develop and test the algorithm, 110 patients diagnosed with SDB participated in this study. Ninety of the subjects underwent full-night polysomnography (PSG) and twenty underwent split-night PSG. The subjects were divided into 50 patients of a training set (full/split: 42/8), 30 of a validation set (full/split: 24/6) and 30 of a test set (full/split: 24/6). In the experiments conducted, sleep-wakefulness classification accuracy was found to be 83.2% in the test set, compared with the PSG scoring results of clinical experts. Furthermore, all four sleep parameters showed higher correlations than the results obtained via PSG (r  ⩾  0.84, p  <  0.05). In order to determine whether the proposed method is applicable to CPAP, sleep-wakefulness classification performances were evaluated for each CPAP in the split-night PSG data. The results indicate that the accuracy and sensitivity of sleep-wakefulness classification by CPAP variation shows no statistically significant difference (p  <  0.05). The contributions made in this study are applicable to the automatic classification of sleep-wakefulness states in CPAP devices and evaluation of the quality of sleep.

Phenotyping Pharyngeal Pathophysiology using Polysomnography in Patients with Obstructive Sleep Apnea.

PubMed

Sands, Scott A; Edwards, Bradley A; Terrill, Philip I; Taranto-Montemurro, Luigi; Azarbarzin, Ali; Marques, Melania; Hess, Lauren B; White, David P; Wellman, Andrew

2018-05-01

Therapies for obstructive sleep apnea (OSA) could be administered on the basis of a patient's own phenotypic causes ("traits") if a clinically applicable approach were available. Here we aimed to provide a means to quantify two key contributors to OSA-pharyngeal collapsibility and compensatory muscle responsiveness-that is applicable to diagnostic polysomnography. Based on physiological definitions, pharyngeal collapsibility determines the ventilation at normal (eupneic) ventilatory drive during sleep, and pharyngeal compensation determines the rise in ventilation accompanying a rising ventilatory drive. Thus, measuring ventilation and ventilatory drive (e.g., during spontaneous cyclic events) should reveal a patient's phenotypic traits without specialized intervention. We demonstrate this concept in patients with OSA (N = 29), using a novel automated noninvasive method to estimate ventilatory drive (polysomnographic method) and using "gold standard" ventilatory drive (intraesophageal diaphragm EMG) for comparison. Specialized physiological measurements using continuous positive airway pressure manipulation were employed for further comparison. The validity of nasal pressure as a ventilation surrogate was also tested (N = 11). Polysomnography-derived collapsibility and compensation estimates correlated favorably with those quantified using gold standard ventilatory drive (R = 0.83, P < 0.0001; and R = 0.76, P < 0.0001; respectively) and using continuous positive airway pressure manipulation (R = 0.67, P < 0.0001; and R = 0.64, P < 0.001; respectively). Polysomnographic estimates effectively stratified patients into high versus low subgroups (accuracy, 69-86% vs. ventilatory drive measures; P < 0.05). Traits were near-identical using nasal pressure versus pneumotach (N = 11, R ≥ 0.98, both traits; P < 0.001). Phenotypes of pharyngeal dysfunction in OSA are evident from spontaneous changes in ventilation and ventilatory drive during sleep, enabling noninvasive phenotyping in the clinic. Our approach may facilitate precision therapeutic interventions for OSA.

The Pressure Distribution over the Horizontal Tail Surfaces of an Airplane III

NASA Technical Reports Server (NTRS)

Norton, F H; Brown, W G

1923-01-01

This report contains the results of an investigation of the distribution of pressure over the tail surfaces of a full-sized airplane during accelerated flight for the purpose of determining the magnitude of the tail and fuselage stresses in maneuvering. As the pressures in accelerated flight change in value with great rapidity, it was found that the liquid manometer used in the first part of this investigation would not be at all suitable under these conditions; so it was necessary to design and construct a new manometer containing a large number of recording diaphragm gauges for these measurements. Sixty openings on the tail surfaces were connected to this manometer and continuous records of pressures for each pair of holes were taken during various maneuvers. There were also recorded, simultaneously with the pressures, the normal acceleration at the center of gravity and the angular position of all the controls. The present investigation consisted in measuring on a standard rigged JN4H airplane the distribution of pressure over the whole of the horizontal tail surfaces while the airplane was being put through maneuvers as violently as it was thought safe, including spinning and pulling out of dives.

A novel APPI-MS setup for in situ degradation product studies of atmospherically relevant compounds: capillary atmospheric pressure photo ionization (cAPPI).

PubMed

Kersten, Hendrik; Derpmann, Valerie; Barnes, Ian; Brockmann, Klaus J; O'Brien, Rob; Benter, Thorsten

2011-11-01

We report on the development of a novel atmospheric pressure photoionization setup and its applicability for in situ degradation product studies of atmospherically relevant compounds. A custom miniature spark discharge lamp was embedded into an ion transfer capillary, which separates the atmospheric pressure from the low pressure region in the first differential pumping stage of a conventional atmospheric pressure ionization mass spectrometer. The lamp operates with a continuous argon flow and produces intense light emissions in the VUV. The custom lamp is operated windowless and efficiently illuminates the sample flow through the transfer capillary on an area smaller than 1 mm(2). Limits of detection in the lower ppbV range, a temporal resolution of milliseconds in the positive as well as the quasi simultaneously operating negative ion mode, and a significant reduction of ion transformation processes render this system applicable to real time studies of rapidly changing chemical systems. The method termed capillary atmospheric pressure photo ionization (cAPPI) is characterized with respect to the lamp emission properties as a function of the operating conditions, temporal response, and its applicability for in situ degradation product studies of atmospherically relevant compounds, respectively.

Obstructive sleep apnea syndrome and erectile dysfunction: does long term continuous positive airway pressure therapy improve erections?

PubMed

Husnu, Tokgoz; Ersoz, Akyurek; Bulent, Erol; Tacettin, Ornek; Remzi, Altin; Bulent, Akduman; Aydin, Mungan

2015-03-01

The aim of this age-matched, controlled, prospective clinical study was to investigate frequency and degree of erectile dysfunction (ED) in patients with obstructive sleep apnea syndrome (OSAS) and to evaluate the results of only continuous positive airway pressure (CPAP) therapy on ED in patients with OSAS. A total of 90 patients were evaluated for potential OSAS. They were given an International Index of Erectile Function questionnaire (IIEF) and Beck Depression Inventory. Sixty-two patients with the diagnosis of OSAS were regarded as study group. Twenty-eight patients in whom the OSAS was excluded, were regarded as the control group. Biochemical and hormonal laboratory evaluation were performed. Then all patients underwent a full-night in laboratory polysomnography examination. The degree of OSAS were evaluated by an expert from chest diseases department. When compared to the control group, a decrease in IIEF-5 scores was found in patients with OSAS. However, this decrease was not statistically significant. After 3 months of CPAP usage in patients with mild to moderate and severe degree OSAS, improvement in IIEF-5 scores was statistically significant. Mean value of IIEF-5 score was 16.63±5.91 before CPAP and were improved up to 20.92±6.79 (P=0.001). It is not certainly possible to say that OSAS is clearly associated with ED. However, after 3 months of regular CPAP usage, ED complaints in patients with OSAS might improve positively. Trials with larger series may give more conclusive data.

[Effect of Continuous Positive Airway Pressure Treatment on Depression, Anxiety and Perceived Stress Levels in Patients with Obstructive Sleep Apnea Syndrome].

PubMed

Çelik, Mustafa; Sarıkaya, Yasin; Acar, Mustafa; Kalenderoğlu, Aysun; Doğan, Sedat; Kaskalan, Emin; Karataş, Mehmet

2016-01-01

The aim of this study is to determine the effects of continuous positive airway pressure (CPAP) treatment on depression, anxiety, and perceived stress levels and to identify factors predictive of treatment efficacy in patients with obstructive sleep apnea syndrome (OSAS). This study included 51 patients admitted to the Adiyaman University Medical School Otorhinolaryngology Department or Eskisehir Yunus Emre State Hospital between January and September 2014 with one or more complaints including snoring, excessive daytime sleepiness, or apnea witnessed by the partner. Diagnosis of OSAS was made by polysomnography and CPAP treatment was initiated. Depression levels were assessed in all study subjects using the Hospital Anxiety and Depression Scale (HADS) at the start of treatment and at 3 months. Anxiety levels were assessed using both the HADS and the State and Trait Anxiety Inventory (STAI), and perceived stress level was assessed using the Perceived Stress Questionnaire (PSQ). After CPAP treatment, we observed significant decreases in both the Depression and Anxiety Subscales of the HADS, in the Trait Anxiety subscale of the STAI, and in the PSQ. An evaluation of the initial parameters that predict improvements in these scales revealed that snoring time predicted decreases in all scale scores. In OSAS patients CPAP treatment has positive effects on psychological parameters like depression, anxiety, and perceived stress. We suggest that possible psychogenic benefits should be considered when deciding to start CPAP treatment, particularly in patients with pronounced and extended snoring who may also have social problems.

Fabrication technique for a custom face mask for the treatment of obstructive sleep apnea.

PubMed

Prehn, Ronald S; Colquitt, Tom

2016-05-01

The development of the positive airway pressure custom mask (TAP-PAP CM) has changed the treatment of obstructive sleep apnea. The TAP-PAP CM is used in continuous positive airway pressure therapy (CPAP) and is fabricated from the impression of the face. This mask is then connected to a post screwed into the mechanism of the TAP3 (Thornton Anterior Positioner) oral appliance. This strapless CPAP face mask features an efficient and stable CPAP interface with mandibular stabilization (Hybrid Therapy). A technique with a 2-stage polyvinyl siloxane face impression is described that offers improvements over the established single-stage face impression. This 2-stage impression technique eliminates problems inherent in the single-stage face impression, including voids, compressed tissue, inadequate borders, and a rushed experience due to the setting time of the single stage. The result is a custom mask with an improved seal to the CPAP device. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Composite Behavior of Insulated Concrete Sandwich Wall Panels Subjected to Wind Pressure and Suction.

PubMed

Choi, Insub; Kim, JunHee; Kim, Ho-Ryong

2015-03-19

A full-scale experimental test was conducted to analyze the composite behavior of insulated concrete sandwich wall panels (ICSWPs) subjected to wind pressure and suction. The experimental program was composed of three groups of ICSWP specimens, each with a different type of insulation and number of glass-fiber-reinforced polymer (GFRP) shear grids. The degree of composite action of each specimen was analyzed according to the load direction, type of the insulation, and number of GFRP shear grids by comparing the theoretical and experimental values. The failure modes of the ICSWPs were compared to investigate the effect of bonds according to the load direction and type of insulation. Bonds based on insulation absorptiveness were effective to result in the composite behavior of ICSWP under positive loading tests only, while bonds based on insulation surface roughness were effective under both positive and negative loading tests. Therefore, the composite behavior based on surface roughness can be applied to the calculation of the design strength of ICSWPs with continuous GFRP shear connectors.

Tracheostomy and mechanical ventilation weaning in children affected by respiratory virus according to a weaning protocol in a pediatric intensive care unit in Argentina: an observational restrospective trial

PubMed Central

2011-01-01

We describe difficult weaning after prolonged mechanical ventilation in three tracheostomized children affected by respiratory virus infection. Although the spontaneous breathing trials were successful, the patients failed all extubations. Therefore a tracheostomy was performed and the weaning plan was begun. The strategy for weaning was the decrease of ventilation support combining pressure control ventilation (PCV) with increasing periods of continuous positive airway pressure + pressure support ventilation (CPAP + PSV) and then CPAP + PSV with increasing intervals of T-piece. They presented acute respiratory distress syndrome on admission with high requirements of mechanical ventilation (MV). Intervening factors in the capabilities and loads of the respiratory system were considered and optimized. The average MV time was 69 days and weaning time 31 days. We report satisfactory results within the context of a directed weaning protocol. PMID:21244710

Renal responses to central vascular expansion are suppressed at night in conscious primates

NASA Technical Reports Server (NTRS)

Kass, D. A.; Sulzman, F. M.; Fuller, C. A.; Moore-Ede, M. C.

1980-01-01

The renal and hemodynamic responses of squirrel monkeys to central vascular volume expansion induced by lower body positive pressure (LBPP) during the day and night are investigated. Twelve unanesthetized animals trained to sit in a metabolism chair in which they were restrained only at the waist by a partition separating upper and lower body chambers were subjected to 4 h of continuous LBPP during the day and night, and hemodynamic, urinary and drinking data were monitored. LBPP during day and night is found to induce similar increases in central venous pressure, rises in heart rate and elevations in mean arterial blood pressure. However, although daytime LBPP induced a significant increase in urine flow and sodium excretion, a marked nocturnal inhibition of the renal response to LBPP is observed. Analysis of the time course and circadian regulation patterns of the urinary responses suggests that several separate efferent control pathways are involved.

Cerebral oxygenation in the beach chair position for shoulder surgery in regional anesthesia: impact on cerebral blood flow and neurobehavioral outcome.

PubMed

Aguirre, José A; Märzendorfer, Olivia; Brada, Muriel; Saporito, Andrea; Borgeat, Alain; Bühler, Philipp

2016-12-01

Beach chair position is considered a potential risk factor for central neurological events particularly if combined with low blood pressure. The aim of this study was to assess the impact of regional anesthesia on cerebral blood flow and neurobehavioral outcome. This is a prospective, assessor-blinded observational study evaluating patients in the beach chair position undergoing shoulder surgery under regional anesthesia. University hospital operating room. Forty patients with American Society of Anesthesiologists classes I-II physical status scheduled for elective shoulder surgery. Cerebral saturation and blood flow of the middle cerebral artery were measured prior to anesthesia and continued after beach chair positioning until discharge to the postanesthesia care unit. The anesthesiologist was blinded for these values. Controlled hypotension with systolic blood pressure≤100mm Hg was maintained during surgery. Neurobehavioral tests and values of regional cerebral saturation, bispectral index, the mean maximal blood flow of the middle cerebral artery, and invasive blood pressure were measured prior to regional anesthesia, and measurements were repeated after placement of the patient on the beach chair position and every 20 minutes thereafter until discharge to postanesthesia care unit. The neurobehavioral tests were repeated the day after surgery. The incidence of cerebral desaturation events was 5%. All patients had a significant blood pressure drop 5 minutes after beach chair positioning, measured at the heart as well as the acoustic meatus levels, when compared with baseline values (P<.05). There was no decrease in either the regional cerebral saturation (P=.136) or the maximal blood flow of the middle cerebral artery (P=.212) at the same time points. Some neurocognitive tests showed an impairment 24 hours after surgery (P<.001 for 2 of 3 tests). Beach chair position in patients undergoing regional anesthesia for shoulder surgery had no major impact on cerebral blood flow and cerebral oxygenation. However, some impact on neurobehavioral outcome 24 hours after surgery was observed. Copyright © 2016 Elsevier Inc. All rights reserved.

System and method for continuous solids slurry depressurization

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

Leininger, Thomas Frederick; Steele, Raymond Douglas; Yen, Hsien-Chin William

A continuous slag processing system includes a rotating parallel disc pump, coupled to a motor and a brake. The rotating parallel disc pump includes opposing discs coupled to a shaft, an outlet configured to continuously receive a fluid at a first pressure, and an inlet configured to continuously discharge the fluid at a second pressure less than the first pressure. The rotating parallel disc pump is configurable in a reverse-acting pump mode and a letdown turbine mode. The motor is configured to drive the opposing discs about the shaft and against a flow of the fluid to control a differencemore » between the first pressure and the second pressure in the reverse-acting pump mode. The brake is configured to resist rotation of the opposing discs about the shaft to control the difference between the first pressure and the second pressure in the letdown turbine mode.« less

Pressure during decision making of continuous sedation in end-of-life situations in Dutch general practice

PubMed Central

2012-01-01

Background Little is known about pressure from patients or relatives on physician’s decision making of continuous palliative sedation. We aim to describe experienced pressure by general practitioners (GPs) in cases of continuous sedation after the introduction of the Dutch practice guideline, using a questionnaire survey. Methods A sample of 918 Dutch GPs were invited to fill out a questionnaire about their last patient under continuous sedation. Cases in which GPs experienced pressure from the patient, relatives or other persons were compared to those without pressure. Results 399 of 918 invite GPs (43%) returned the questionnaire and 250 provided detailed information about their most recent case of continuous sedation. Forty-one GPs (16%) indicated to have experienced pressure from the patient, relatives or colleagues. In GPs younger than 50, guideline knowledge was not related to experienced pressure, whereas in older GPs, 15% with and 36% without guideline knowledge reported pressure. GPs experienced pressure more often when patients had psychological symptoms (compared to physical symptoms only) and when patients had a longer estimated life expectancy. A euthanasia request of the patient coincided with a higher prevalence of pressure for GPs without, but not for GPs with previous experience with euthanasia. GPs who experienced pressure had consulted a palliative consultation team more often than GPs who did not experience pressure. Conclusion One in six GPs felt pressure from patients or relatives to start sedation. This pressure was related to guideline knowledge, especially in older GPs, longer life expectancy and the presence of a euthanasia request, especially for GPs without previous experience of euthanasia. PMID:22759834

Randomised prospective parallel trial of therapeutic versus subtherapeutic nasal continuous positive airway pressure on simulated steering performance in patients with obstructive sleep apnoea

PubMed Central

Hack, M.; Davies, R.; Mullins, R.; Choi, S. J.; Ramdassingh-Dow, S.; Jenkinson, C.; Stradling, J.

2000-01-01

BACKGROUND—Obstructive sleep apnoea (OSA) impairs vigilance and may lead to an increased rate of driving accidents. In uncontrolled studies accident rates and simulated steering performance improve following treatment with nasal continuous positive airway pressure (NCPAP). This study seeks to confirm the improvement in steering performance in a randomised controlled trial using subtherapeutic NCPAP as a control treatment.
METHODS—Fifty nine men with OSA (Epworth Sleepiness Score (ESS) of ⩾10, and ⩾10/h dips in SaO2 of >4% due to OSA) received therapeutic or subtherapeutic NCPAP (≈1 cm H2O) for one month. Simulated steering performance over three 30-minute "drives" was quantified as: standard deviation (SD) of road position, deterioration in SD across the drive, length of drive before "crashing", and number of off-road events. The reaction times to peripheral target stimuli during the drive were also measured.
RESULTS—Subtherapeutic NCPAP did not improve overnight >4% SaO2 dips/h compared with baseline values, thus acting as a control. The SD of the steering position improved from 0.36 to 0.21 on therapeutic NCPAP, and from 0.35 to 0.30 on subtherapeutic NCPAP (p = 0.03). Deterioration in SD of the steering position improved from 0.18to 0.06 SD/h with therapeutic NCPAP and worsened from 0.18 to 0.24 with subtherapeutic NCPAP (p = 0.04). The reaction time to target stimuli was quicker after therapeutic than after subtherapeutic NCPAP (2.3 versus 2.7 seconds, p = 0.04).
CONCLUSIONS—Therapeutic NCPAP improves steering performance and reaction time to target stimuli in patients with OSA, lending further support to the hypothesis that OSA impairs driving, increases driving accident rates, and that these improve following treatment with NCPAP.

 PMID:10679542

A Randomized Crossover Trial Evaluating Continuous Positive Airway Pressure Versus Mandibular Advancement Device on Health Outcomes in Veterans With Posttraumatic Stress Disorder

PubMed Central

El-Solh, Ali A.; Homish, Gregory G.; Ditursi, Guy; Lazarus, John; Rao, Nithin; Adamo, David; Kufel, Thomas

2017-01-01

Study Objectives: Despite the overall improvement in posttraumatic stress disorder (PTSD) symptomatology with continuous positive airway pressure (CPAP) therapy, adherence to CPAP is far worse in veterans with PTSD compared to the general population with obstructive sleep apnea (OSA). The aim of this study was to compare the efficacy, adherence, and preference of CPAP versus mandibular advancement device (MAD) and the effect of these treatments on health outcomes in veterans with PTSD. Methods: Forty-two subjects with PTSD and newly diagnosed OSA by polysomnography were treated in a randomized, crossover trial of 12 weeks with CPAP alternating with MAD separated by a 2-week washout period. The primary outcome was the difference in titration residual apnea-hypopnea index (AHI) between CPAP and MAD. Secondary outcome measures included PTSD Checklist and health-related quality of life (Medical Outcomes Study 36-Item Short Form and Pittsburgh Sleep Quality Index). Results: Analyses were limited to the 35 subjects (mean age 52.7 ± 11.6 years) who completed the trial, regardless of compliance with their assigned treatment. CPAP was more efficacious in reducing AHI and improving nocturnal oxygenation than MAD (P < .001 and P = .04, respectively). Both treatments reduced PTSD severity and ameliorated scores of the Medical Outcomes Study Short Form 36 and Pittsburgh Sleep Quality Index, although no differences were detected between the CPAP and MAD arms. The reported adherence to MAD was significantly higher than CPAP (P < .001), with 58% preferring MAD to CPAP. Conclusions: Although CPAP is more efficacious than MAD at improving sleep apnea, both treatment modalities imparted comparable benefits for veterans with PTSD in relation to PTSD severity and health-related quality of life. MAD offers a viable alternative for veterans with OSA and PTSD who are nonadherent to CPAP. Clinical Trial Registration: Title: A Randomized Cross Over Trial of Two Treatments for Sleep Apnea in Veterans With Post-Traumatic Stress Disorder; URL: https://www.clinicaltrials.gov/ct/show/NCT01569022; Identifier: NCT01569022 Citation: El-Solh AA, Homish GG, Ditursi G, Lazarus J, Rao N, Adamo D, Kufel T. A randomized crossover trial evaluating continuous positive airway pressure versus mandibular advancement device on health outcomes in veterans with posttraumatic stress disorder. J Clin Sleep Med. 2017;13(11):1327–1335 PMID:29065960

Maternal Blood Pressure During Pregnancy and Early Childhood Blood Pressures in the Offspring

PubMed Central

Lim, Wai-Yee; Lee, Yung-Seng; Yap, Fabian Kok-Peng; Aris, Izzudin Mohd; Ngee, Lek; Meaney, Michael; Gluckman, Peter D.; Godfrey, Keith M.; Kwek, Kenneth; Chong, Yap-Seng; Saw, Seang-Mei; Pan, An

2015-01-01

Abstract Although epidemiological studies suggest that offspring of women with preeclampsia are at increased risk to higher blood pressures and cardiovascular disease, little is known about the nature of blood pressures between the mother and her offspring. As blood pressures comprise of both pulsatile (systolic blood pressure [SBP] and pulse pressure [PP]) and stable (diastolic blood pressure [DBP]) components, and they differ between central and peripheral sites, we sought to examine maternal peripheral and central blood pressure components in relation to offspring early childhood blood pressures. A prospective birth cohort of 567 Chinese, Malay, and Indian mother–offspring with complete blood pressure information were studied. Maternal brachial artery SBP, DBP, and PP were measured at 26 to 28 weeks gestation; and central SBP and PP were estimated from radial artery waveforms. Offspring brachial artery SBP, DBP, and PP were measured at 3 years of age. Associations between continuous variables of maternal blood pressures (peripheral SBP, DBP, PP, central SBP, and PP) and offspring blood pressures (peripheral SBP, DBP, and PP) were examined using multiple linear regression with adjustment for maternal characteristics (age, education level, parity, smoking status, alcohol consumption and physical activity during pregnancy, and pre-pregnancy BMI) and offspring characteristics (sex, ethnicity, BMI, and height at 3 years of age). In the multivariate models, offspring peripheral SBP increased by 0.08 (95% confidence interval 0.00–0.17, P = 0.06) mmHg with every 1-mmHg increase in maternal central SBP, and offspring peripheral PP increased by 0.10 (0.01–0.18, P = 0.03) mmHg for every 1-mmHg increase in maternal central PP. The relations of maternal-offspring peripheral blood pressures (SBP, DBP, and PP) were positive but not statistically significant, and the corresponding values were 0.05 (−0.03 to 0.13; P = 0.21), 0.03 (−0.04 to 0.10; P = 0.35), and 0.05 (−0.02 to 0.13; P = 0.14), respectively. Maternal central pulsatile blood pressure components (SBP and PP) during pregnancy are associated with higher blood pressures in the offspring. This positive correlation is already evident at 3-years old. Studies are needed to further evaluate the effects of maternal central pulsatile blood pressure components during pregnancy and long-term cardiovascular health in the offspring. PMID:26559279

Factors associated with the self-perceived ability of nursing staff to remain working until retirement: a questionnaire survey.

PubMed

Maurits, Erica E M; de Veer, Anke J E; van der Hoek, Lucas S; Francke, Anneke L

2015-09-02

It is important to learn how employers in European countries can prevent nursing staff from changing occupation or taking early retirement in order to counteract expected nursing shortages. However, to date research on nursing staff's ability to remain working until retirement age has been limited. The purpose of this study was to gain insight into the associations between different job and organisational characteristics, job satisfaction, occupational commitment and the self-perceived ability to continue working in the current line of work until the official retirement age. The questionnaire-based, cross-sectional study included 730 nursing staff members employed in Dutch hospitals, nursing homes, organisations for psychiatric care, homes for the elderly, care organisations for disabled people and home care organisations (mean age: 48; 89% female). Linear and logistic regression analyses and mediation analyses were applied to test hypothesised associations. Reducing work pressure and increasing appreciation by senior management in particular have positive consequences for nursing staff's self-perceived ability to continue working until the official retirement age. The job and organisational characteristics of autonomy, work pressure, supportive leadership, educational opportunities, communication within the organisation and appreciation of nursing staff by senior management together have substantial impact on nursing staff's job satisfaction. Job satisfaction in turn is related to the self-perceived ability to continue working until the retirement age. However, job satisfaction mainly summarises the joint effect of job and organisational characteristics and has no supplementary effect on the self-perceived ability to continue working. Employers should primarily focus on work pressure and the appreciation of nursing staff by senior management in order to retain nursing staff even as they get older.

Electrochemical cell having improved pressure vent

DOEpatents

Dean, Kevin; Holland, Arthur; Fillmore, Donn

1993-01-01

The electrochemical cell of the instant invention includes a case having a gas outlet, one or more positive electrodes positioned within the case, one or more negative electrodes positioned within the case electrode separators positioned between the positive and negative electrodes, electrolyte positioned within the case, and a pressure vent for releasing internal pressure occurring in the case to the surrounding atmosphere. The pressure vent is affixed to the case covering the gas outlet, the pressure vent includes a vent housing having a hollow interior area in gaseous communication with the surrounding atmosphere and the interior of the case via the gas outlet, a pressure release piston positioned within the hollow interior area, the pressure release piston sized to surround the gas outlet and having a seal groove configured to encapsulate all but one surface of a seal mounted within the seal groove, leaving the non-encapsulated surface of the seal exposed, and a compression spring positioned to urge the pressure release piston to compress the seal in the seal groove and block the gas outlet in the case.

Palmar pressure distribution during push-up exercise.

PubMed

Chuckpaiwong, B; Harnroongroj, T

2009-07-01

Doing repetitive push-ups is among the most common exercise for the upper body and shoulder stabiliser muscle strength training. However, adverse effects such as neck pain, back pain, palmar pain and wrist pain have been reported. To date, to our knowledge, palmar pressure when performing push-ups has not been previously reported. We hypothesised that various hand positions during push-ups may provide different palmar pressures. Bilateral palmar pressures were recorded in ten individual volunteers. All the subjects were set up for doing push-ups in five positions of the hand. Peak palmar pressure was recorded by Emed pressure platform system (Novel GmBH, Munich, Germany). The palm was divided into the following five anatomic regions, viz. thenar, lunate, hypothenar, metacarpals and fingers. Statistical comparison between the five positions of the hand was analysed using the analysis of variance test. A distribution of the mean peak pressure of the lunate and hypothenar areas were relatively higher than the other areas in both standby and full-elbow flexion positions. At the palmar position 30 cm wider than the shoulder width, the palmar pressure revealed significantly higher peak pressure in the lunate area in the standby and fully-flexed elbow positions (p-value is less than 0.05). At the palmar position 10 cm narrower than the shoulder width, palmar pressure showed significantly higher peak pressure in the hypothenar area only in the fully-flexed elbow position. The information regarding palmar pressures while performing push-ups in different hand positions may be used as a guideline for exercise modification, especially in injured athletes.

Continuous positive airway pressure and liver enzymes in obstructive sleep apnoea: data from a randomized controlled trial.

PubMed

Kohler, Malcolm; Pepperell, Justin C T; Davies, Robert J O; Stradling, John R

2009-01-01

Obstructive sleep apnoea syndrome (OSAS) has been suggested to be an independent risk factor for non-alcoholic fatty liver disease (NAFLD), possibly via intermittent hypoxia that influences blood pressure, lipid levels and insulin resistance, factors themselves known to cause NAFLD. In observational studies, OSAS has been associated with elevated levels of liver enzymes. Continuous positive airway pressure (CPAP) is the treatment for OSAS, but the effects of CPAP on liver enzymes have not been studied in a randomized controlled trial. To determine if 4 weeks of CPAP influence alanine-aminotransferase (ALT) and aspartate-aminotranferase (AST) levels. 94 patients with moderate-to-severe OSAS were randomized to therapeutic or sub-therapeutic CPAP treatment. Plasma ALT and AST were measured before and after 4 weeks of CPAP. Results are means +/- SD. ALT levels decreased from 39.1 +/- 26.3 to 30.3 +/- 16.4 IU/l in patients treated with therapeutic CPAP, but also decreased from 36.9 +/- 20.7 to 31.5 +/- 16.5 IU/l in patients treated with sub-therapeutic CPAP (difference between mean changes -3.4, 95% CI -7.8 to 1.0 IU/l, p = 0.13 between groups). AST levels did not change significantly with therapeutic CPAP (from 29.1 +/- 14.7 to 30.2 +/- 13.6 IU/l), nor with sub-therapeutic CPAP (from 28.2 +/- 16.2 to 29.5 +/- 12.6 IU/l; difference between mean changes -0.2, 95% CI -3.0 to 2.6 IU/l, p = 0.87 between groups). Four weeks of active CPAP has no beneficial effect on aminotransferase levels when compared to sub-therapeutic CPAP in patients with OSAS. Therefore, CPAP does not seem to improve biochemical markers of potential NAFLD in OSAS patients.

Adaptation to a blood pressure telemetry system revealed by measures of activity, agility and operant learning in mice.

PubMed

Popova, Anfisa; Tsvirkun, Darya; Dolgov, Oleg; Anokhin, Konstantin; Alberts, Jeffrey; Lagereva, Evgeniia; Custaud, Marc-Antoine; Gauquelin-Koch, Guillemette; Vinogradova, Olga; Andreev-Andrievskiy, Alexander

Implantable telemetry enables continuous monitoring of physiological functions in freely moving animals and can greatly complement pharmacological research. Despite its miniaturization, a sensor/transmitter constitutes 5% or more of a mouse's bodyweight. The aim of the present study was to evaluate whether factors related to the presence of a probe/transmitter influence the ambulatory activity, strength, agility, or operant, motivated behaviors of this small rodent. Adult male mice (C57BL/6N, 22-25g, 9-10weeks; implanted n=26, intact n=45) were evaluated during week-long tests, conducted three and eight weeks after surgical implantation of the PA-C10 blood pressure probe. An open field test, grip force measurement, Rotarod test were performed, followed by 7-day continuous monitoring of spontaneous wheel running activity and positively reinforced operant conditioning in an automated data collection system. An implanted blood pressure transmitter did not affect behavior of mice in the open field test, on the Rotarod or their grip force, compared to unoperated controls. Voluntary wheel running distance was reduced three, but not eight weeks after implantation. Three weeks after the surgery, performance in the positively reinforced operant conditioning in operated mice was slightly decreased compared to intact animals, while retention and acquisition of a 2nd, reversal-learning task eight weeks after the surgery were unaffected. We conclude that an implantable transmitter may have detectable effects in the first few weeks following implantation on some elements of mouse behavior. With sufficient recovery, mice perform comparably to unoperated controls in tests of strength, endurance, agility and learned operant behavior. Copyright © 2017 Elsevier Inc. All rights reserved.

Non-invasive continuous blood pressure measurement based on mean impact value method, BP neural network, and genetic algorithm.

PubMed

Tan, Xia; Ji, Zhong; Zhang, Yadan

2018-04-25

Non-invasive continuous blood pressure monitoring can provide an important reference and guidance for doctors wishing to analyze the physiological and pathological status of patients and to prevent and diagnose cardiovascular diseases in the clinical setting. Therefore, it is very important to explore a more accurate method of non-invasive continuous blood pressure measurement. To address the shortcomings of existing blood pressure measurement models based on pulse wave transit time or pulse wave parameters, a new method of non-invasive continuous blood pressure measurement - the GA-MIV-BP neural network model - is presented. The mean impact value (MIV) method is used to select the factors that greatly influence blood pressure from the extracted pulse wave transit time and pulse wave parameters. These factors are used as inputs, and the actual blood pressure values as outputs, to train the BP neural network model. The individual parameters are then optimized using a genetic algorithm (GA) to establish the GA-MIV-BP neural network model. Bland-Altman consistency analysis indicated that the measured and predicted blood pressure values were consistent and interchangeable. Therefore, this algorithm is of great significance to promote the clinical application of a non-invasive continuous blood pressure monitoring method.

Biosensor System for Continuous Monitoring of Organophosphate Aerosols (Postprint)

DTIC Science & Technology

2007-05-01

performed by chromatog- aphy coupled with mass selective detectors or various types of pectroscopy (Staaf and Ostman, 2005; Bjorklund et al., 2004...diverted to aste while the bubble-free flow was directed through the IMER olumns and into a single wavelength absorbance detector . The ow rate was...maintained at 2 ml/min by a second piston pump ositioned between the debubbler and the IMER columns so that he sample was under positive pressure as it

A simple circuit to deliver bubbling CPAP.

PubMed

Kaur, Charanjit; Sema, Akatoli; Beri, Rajbir S; Puliyel, Jacob M

2008-04-01

Nasal continuous positive airway pressure (CPAP), especially bubbling CPAP, is known to reduce the need for more invasive ventilation. We here describe a circuit that can deliver bubbling CPAP in resource poor settings. We describe how the oxygen concentration can be altered from 98% to 21% oxygen using this system. Addition of a humidifier in the circuit has the effect of reducing the oxygen concentration by 1 to 5%. The cost of putting together the system is approximately Rs 5000.

Effect of Nasal Continuous Positive Pressure on the Nostrils of Patients with Sleep Apnea Syndrome and no Previous Nasal Pathology. Predictive Factors for Compliance.

PubMed

Aguilar, Francina; Cisternas, Ariel; Montserrat, Josep Maria; Àvila, Manuel; Torres-López, Marta; Iranzo, Alex; Berenguer, Joan; Vilaseca, Isabel

2016-10-01

To evaluate the effect of continuous positive airway pressure (CPAP) on the nostrils of patients with sleep apnea-hypopnea syndrome and its impact on quality of life, and to identify predictive factors for compliance. Longitudinal prospective study. Thirty-six consecutive patients evaluated before and 2 months after CPAP using the following variables: clinical (eye, nose and throat [ENT] symptoms, Epworth test, anxiety/depression scales, general and rhinoconjunctivitis-specific quality of life); anatomical (ENT examination, computed tomography); functional (auditive and Eustachian tube function, nasal flow, mucociliary transport); biological (nasal cytology); and polisomnographics. The sample was divided into compliers (≥4h/d) and non-compliers (<4h/d). A significant improvement was observed in daytime sleepiness (p=0.000), anxiety (P=.006), and depression (P=.023). Nasal dryness (P=.000), increased neutrophils in nasal cytology (P=.000), and deteriorating ciliary function were evidenced, particularly in compliers. No significant differences were observed in the other variables. Baseline sleepiness was the only factor predictive of compliance. CPAP in patients without previous nasal pathology leads to an improvement in a series of clinical parameters and causes rhinitis and airway dryness. Some ENT variables worsened in compliers. Sleepiness was the only prognostic factor for poor tolerance. Copyright © 2016 SEPAR. Publicado por Elsevier España, S.L.U. All rights reserved.

Effect of continuous positive airway pressure treatment on short-term memory performance over 24 h of sustained wakefulness in patients with obstructive sleep apnea-hypopnea syndrome.

PubMed

Grenèche, Jérôme; Krieger, Jean; Bertrand, Frédéric; Erhardt, Christine; Maumy, Myriam; Tassi, Patricia

2013-10-01

Few studies have examined the impact of continuous positive airway pressure (CPAP) therapy on short-term memory (STM) over sustained wakefulness in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). We have investigated if impaired STM can be reversed by CPAP treatment in a 24-h sustained wakefulness paradigm. Our follow-up study was conducted with repeated-memory tasks within 12 OSAHS patients and 10 healthy controls who underwent three 32-h sessions, one before CPAP (T0) and the second (T3) and the third (T6), after 3 and 6 months of treatment, respectively, for OSAHS patients. Each session included one night of sleep followed by 24h of sustained wakefulness, during which both groups performed STM tasks including both digit span (DS) and Sternberg tasks. Untreated OSAHS patients had no deficit in the forward DS task measuring immediate memory but were impaired in STM, especially working memory assessed by the complex Sternberg task and the backward DS. However, only performance in the latter was improved after 6 months of CPAP treatment. Because the high level of memory scanning required high speed in information processing, persistent impairment on the complex Sternberg task may be attributable to working memory slowing, possibly enhanced by sustained wakefulness. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Rapid systematic review shows that using a high-flow nasal cannula is inferior to nasal continuous positive airway pressure as first-line support in preterm neonates.

PubMed

Conte, Francesca; Orfeo, Luigi; Gizzi, Camilla; Massenzi, Luca; Fasola, Salvatore

2018-05-11

We reviewed using a high-flow nasal cannula (HFNC) as first-line support for preterm neonates with, or at risk of, respiratory distress. This rapid systematic review covered biomedical databases up to June 2017. We included randomised controlled trials (RCTs) published in English. The reference lists of the studies and relevant reviews we included were also screened. We performed the study selection, data extraction, study quality assessment, meta-analysis and quality of evidence assessment following the Grading of Recommendations Assessment, Development and Evaluation system. Pooled results from six RCTs covering 1227 neonates showed moderate-quality evidence that HFNC was associated with a higher rate of failure than nasal continuous positive airway pressure (NCPAP) in preterm neonates of at least 28 weeks of gestation, with a risk ratio of 1.57. Low-quality evidence showed no significant differences between HFNC and NCPAP in the need for intubation and bronchopulmonary dysplasia rate. HFNC yielded a lower rate of nasal injury (risk ratio 0.50). When HFNC failed, intubation was avoided in some neonates by switching them to NCPAP. HFNC had higher failure rates than NCPAP when used as first-line support. Subsequently switching to NCPAP sometimes avoided intubation. Data on the most immature neonates were lacking. ©2018 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

Meta-analysis of randomised controlled trials of oral mandibular advancement devices and continuous positive airway pressure for obstructive sleep apnoea-hypopnoea

PubMed Central

Sharples, Linda D.; Clutterbuck-James, Abigail L.; Glover, Matthew J.; Bennett, Maxine S.; Chadwick, Rebecca; Pittman, Marcus A.; Quinnell, Timothy G.

2017-01-01

Summary Obstructive sleep apnoea-hypopnoea (OSAH) causes excessive daytime sleepiness, impairs quality-of-life, and increases cardiovascular disease and road traffic accident risks. Continuous positive airway pressure (CPAP) treatment and mandibular advancement devices (MAD) have been shown to be effective in individual trials but their effectiveness particularly relative to disease severity is unclear. A MEDLINE, Embase and Science Citation Index search updating two systematic reviews to August 2013 identified 77 RCTs in adult OSAH patients comparing: MAD with conservative management (CM); MAD with CPAP; or CPAP with CM. Overall MAD and CPAP significantly improved apnoea-hypopnoea index (AHI) (MAD −9.3/hr (p < 0.001), CPAP −25.4 (p < 0.001)). In direct comparisons mean AHI and Epworth sleepiness scale score were lower (7.0/hr (p < 0.001) and 0.67 (p = 0.093) respectively) for CPAP. There were no CPAP vs. MAD trials in mild OSAH but in comparisons with CM, MAD and CPAP reduced ESS similarly (MAD 2.01 (p < 0.001); CPAP 1.23 (p = 0.012). Both MAD and CPAP are clinically effective in the treatment of OSAH. Although CPAP has a greater treatment effect, MAD is an appropriate treatment for patients who are intolerant of CPAP and may be comparable to CPAP in mild disease. PMID:26163056

Estimates of cost-effectiveness of prehospital continuous positive airway pressure in the management of acute pulmonary edema.

PubMed

Hubble, Michael W; Richards, Michael E; Wilfong, Denise A

2008-01-01

To estimate the cost-effectiveness of continuous positive airway pressure (CPAP) in managing prehospital acute pulmonary edema in an urban EMS system. Using estimates from published reports on prehospital and emergency department CPAP, a cost-effectiveness model of implementing CPAP in a typical urban EMS system was derived from the societal perspective as well as the perspective of the implementing EMS system. To assess the robustness of the model, a series of univariate and multivariate sensitivity analyses was performed on the input variables. The cost of consumables, equipment, and training yielded a total cost of $89 per CPAP application. The theoretical system would be expected to use CPAP 4 times per 1000 EMS patients and is expected to save 0.75 additional lives per 1000 EMS patients at a cost of $490 per life saved. CPAP is also expected to result in approximately one less intubation per 6 CPAP applications and reduce hospitalization costs by $4075 per year for each CPAP application. Through sensitivity analyses the model was verified to be robust across a wide range of input variable assumptions. Previous studies have demonstrated the clinical effectiveness of CPAP in the management of acute pulmonary edema. Through a theoretical analysis which modeled the costs and clinical benefits of implementing CPAP in an urban EMS system, prehospital CPAP appears to be a cost-effective treatment.

Cost-effectiveness of Continuous Positive Airway Pressure Treatment in Moderate-Severe Obstructive Sleep Apnea Syndrome.

PubMed

Català, Raquel; Villoro, Renata; Merino, María; Sangenís, Sandra; Colomés, Lluís; Hernández Flix, Salvador; Pérez de Llano, Luis A

2016-09-01

The socioeconomic impact of obstructive sleep apnea-hypopnea syndrome (OSAHS) is considerable. The aim of this study was to evaluate the cost-effectiveness of treating OSAHS with continuous positive airway pressure (CPAP) and the impact of CPAP compliance. This was a retrospective, case-crossover study of 373 patients with OSAHS receiving CPAP. We compared changes in costs, Epworth score and health-related quality of life (EQ-5D questionnaires) between the year before treatment and the year after treatment. The incremental cost-effectiveness ratio (ICER) for the first year of treatment was estimated, and projections were made for the second year, using different effectiveness and cost scenarios. The visual analog scale score for the EQ-5D questionnaire increased by 5 points and the Epworth score fell by 10 points during the year of CPAP treatment. Mean gain in quality-adjusted life years (QALY) was 0.05 per patient per year (P<.001): 0.07 among compliers and -0.04 among non-compliers. ICER was €51,147/QALY during the first year of CPAP treatment and €1,544/QALY during the second year. CPAP treatment in patients with moderate-severe OSAHS improves the quality of life of compliant patients, and is cost-effective as of the second year. Copyright © 2016 SEPAR. Publicado por Elsevier España, S.L.U. All rights reserved.

Understanding motivation for substance use treatment: the role of social pressure during the transition to adulthood.

PubMed

Goodman, Ilana; Peterson-Badali, Michele; Henderson, Joanna

2011-06-01

Research has shown that social pressure is related to treatment motivation and plays an important role in treatment engagement in adults with problematic substance use. Despite the shifts in autonomy and decision-making in emerging adulthood, the factors affecting treatment motivation (e.g., readiness to comply with treatment) during this period have been largely ignored. In this cross sectional study, 134 youth (83 males and 51 females) presenting to an outpatient substance abuse program completed questionnaires regarding substance use history, mental health, social pressure to reduce use and enter treatment, and treatment motivation. Age was positively related to identification of internal reasons for seeking treatment and negatively related to external coercive social pressures as a motivator for treatment. Peer pressure accounted for significant variance in Identified (e.g., personal choice and commitment to the program) and Introjected (e.g., guilt about continued substance use) treatment motivation. Family pressure was related only to External treatment motivation when peer pressure was considered in the regression model. These results highlight the importance of emerging adult peers as motivators of youths' treatment seeking. Limitations, directions for future research and treatment implications are discussed. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Design of a new controller to treat the obstructive sleep apnea

NASA Astrophysics Data System (ADS)

Netzel, Thomas

2002-06-01

The obstructive sleep apnoea (OSA) is a sleep related breathing disorder caused by a relaxation of the upper airway structure during the sleep that leads to a complete closure of the upper airway. The most successful therapy is the nasal continuous positive airway pressure (nCPAP) treatment that keeps the airway opened. More recent devices use an automatic adaptation of the applied pressure. Either the forced oscillation technique (FOT) or the evaluation of the inspiration flow contour are used to evaluate the severity of obstructions. Both methods have disadvantages that may lead to wrong applied pressures. Based on the precise measurement of airflow and mask pressure during nCPAP with a Weinmann SOMNOsmart and additional polysomnography a new parameter set is presented that uses the advantage of both methods to detect the obstructive sleep apnoea. To evaluate the applicability of this parameter set to control Auto-nCPAP-devices a fuzzy-controller is designed under MATLAB/Simulink using an A/D-D/A-converter to control the blower of the SOMNOsmart during Auto-nCPAP-therapy. Obstructive events are detected and treated with a rise of nCPAP-pressure depending on the inspiratory flow requirement. The pressure is lowered after the end of flow limited phases. Although temporary low pressures no oxygen desaturation is recognized by the pulse oxymeter.

Continuous inline blending of antimisting kerosene

NASA Technical Reports Server (NTRS)

Parikh, P.; Yavrouian, A.; Sarohia, V.

1985-01-01

A continuous inline blender was developed to blend polymer slurries with a stream of jet A fuel. The viscosity of the slurries ranged widely. The key element of the blender was a static mixer placed immediately downstream of the slurry injection point. A positive displacement gear pump for jet A was employed, and a progressive cavity rotary screw pump was used for slurry pumping. Turbine flow meters were employed for jet A metering while the slurry flow rate was calibrated against the pressure drop in the injection tube. While using one of the FM-9 variant slurries, a provision was made for a time delay between the addition of slurry and the addition of amine sequentially into the jet A stream.

Continuous-Reading Cryogen Level Sensor

NASA Technical Reports Server (NTRS)

Barone, F. E.; Fox, E.; Macumber, S.

1984-01-01

Two pressure transducers used in system for measuring amount of cryogenic liquid in tank. System provides continuous measurements accurate within 0.03 percent. Sensors determine pressure in liquid and vapor in tank. Microprocessor uses pressure difference to compute mass of cryogenic liquid in tank. New system allows continuous sensing; unaffected by localized variations in composition and density as are capacitance-sensing schemes.

Impact of space flight on cardiovascular autonomic control

NASA Astrophysics Data System (ADS)

Beckers, F.; Verheyden, B.; Morukov, B.; Aubert, Ae

Introduction: Space flight alters the distribution of blood in the human body, leading to altered cardiovascular neurohumoral regulation with a blunted carotid-cardiac baroreflex. These changes contribute to the occurrence of orthostatic intolerance after space flight. Heart rate variability (HRV) and blood pressure variability (BPV) provide non-invasive means to study the autonomic modulation of the heart. Low frequency (LF) oscillations provide information about sympathetic modulation and baroreflex, while high frequency (HF) modulation is an index of vagal heart rate modulation. Methods: ECG and continuous blood pressure were measured for at least 10 minutes in supine, sitting and standing position 45 days and 10 days (L-45, L-10) before launch; and at 1, 2, 4, 9, 15, 19 and 25 days after return to earth (R+x). In space, ECG and continuous blood pressure were measured at day 5 (FD5) and day 8 (FD8). These measurements were performed in 3. HRV and BPV indices were calculated in time and frequency domain. Results: Measurements in supine position and sitting position did not show as high differences as the measurements in standing position. During space flight heart rate was significantly lower compared to the pre- and post-flight measurements in standing position (RR-values: L-45: 837± 42 ms; FD5: 1004± 40 ms; FD8: 1038± 53 ms; R+1: 587± 21 ms; p<0.05). This was accompanied by a significant increase in the proportion of HF power during space flight and a decrease in LF power. Immediately after space flight both LF and HF modulation of heart rate were extremely depressed compared to the pre-flight conditions (p<0.005). A gradual recovery towards baseline conditions of both indices was observed up to 25 days after return from space (LF: L-45: 3297± 462 ms2; FD5: 1251± 332 ms2; FD8: 1322± 462 ms2; R+1: 547± 188 ms2; R+4: 1958± 709 ms2; R+9: 1220± 148 ms2; R+15: 1704± 497 ms2; R+25: 2644± 573 ms2). However, even 25 days after return, values were below baseline condition. Mean systolic blood pressure did not differ significantly before during and after space flight. In space both LF and HF were decreased compared the standing measurements pre- and post-flight. No evolution was present in BPV after return to Earth. Conclusion: During space flight autonomic modulation is characterised by a vagal predominance. Immediately after return to Earth overall autonomic modulation is extremely depressed. Vasomotor autonomic control is restored rather quickly after space flight, while the restoration of autonomic modulation of heart rate is very slow.

Parental and coach support or pressure on psychosocial outcomes of pediatric athletes in soccer.

PubMed

Ommundsen, Yngvar; Roberts, Glyn C; Lemyre, Pierre-Nicolas; Miller, Blake W

2006-11-01

The purpose of this article was to examine supportive and/or pressuring influences of parents and coaches on young athletes' maladaptive perfectionist tendencies, relationships to friends, and competency perceptions in soccer. Previous research has revealed that parents and coaches may give rise to both enjoyable and stressful sport experiences for the pediatric athlete and that parents and coaches are thus able to influence whether young people decide to quit sport or continue participating. Less is known about the relation of supportive versus pressuring parental and coach behaviors on the quality of athletes' achievement striving, relationships to friends in sport, and their competence perceptions. Such knowledge may help create a better psychological sport experience for pediatric athletes. A questionnaire-based cross-sectional field study was carried out among 677 young Norwegian soccer players (aged 10 to 14 years; 504 boys, 173 girls; mean age: boys = 11.9 years, SD = 2.9; girls = 11.2 years, SD = 2.1) taking part in the Norway Cup international youth soccer tournament in 2001. Multivariate analysis of variance (MANOVA) with follow-up canonical correlation was used to examine multivariate relationships between supportive and pressuring behavior and athletes' psychosocial experiences. Joint pressuring behaviors from parents and coaches related positively to maladaptive achievement striving, as indicated by overconcern for mistakes, doubt about one's soccer actions, and lowered perceptions of soccer competence. Mirroring these findings, predominantly supportive coach-created psychological climates were related to a linear pattern of psychological outcomes comprising high-quality friendships, positive competency perceptions, and the absence of specific worries related to achievement striving. Supportive, mastery-oriented coach influence seems beneficial for constructive psychosocial outcomes in pediatric athletes, and athletes experiencing a joint social pressure to excel from coaches and parents may benefit less psychosocially through sport.

Implementing a bedside assessment of respiratory mechanics in patients with acute respiratory distress syndrome.

PubMed

Chen, Lu; Chen, Guang-Qiang; Shore, Kevin; Shklar, Orest; Martins, Concetta; Devenyi, Brian; Lindsay, Paul; McPhail, Heather; Lanys, Ashley; Soliman, Ibrahim; Tuma, Mazin; Kim, Michael; Porretta, Kerri; Greco, Pamela; Every, Hilary; Hayes, Chris; Baker, Andrew; Friedrich, Jan O; Brochard, Laurent

2017-04-04

Despite their potential interest for clinical management, measurements of respiratory mechanics in patients with acute respiratory distress syndrome (ARDS) are seldom performed in routine practice. We introduced a systematic assessment of respiratory mechanics in our clinical practice. After the first year of clinical use, we retrospectively assessed whether these measurements had any influence on clinical management and physiological parameters associated with clinical outcomes by comparing their value before and after performing the test. The respiratory mechanics assessment constituted a set of bedside measurements to determine passive lung and chest wall mechanics, response to positive end-expiratory pressure, and alveolar derecruitment. It was obtained early after ARDS diagnosis. The results were provided to the clinical team to be used at their own discretion. We compared ventilator settings and physiological variables before and after the test. The physiological endpoints were oxygenation index, dead space, and plateau and driving pressures. Sixty-one consecutive patients with ARDS were enrolled. Esophageal pressure was measured in 53 patients (86.9%). In 41 patients (67.2%), ventilator settings were changed after the measurements, often by reducing positive end-expiratory pressure or by switching pressure-targeted mode to volume-targeted mode. Following changes, the oxygenation index, airway plateau, and driving pressures were significantly improved, whereas the dead-space fraction remained unchanged. The oxygenation index continued to improve in the next 48 h. Implementing a systematic respiratory mechanics test leads to frequent individual adaptations of ventilator settings and allows improvement in oxygenation indexes and reduction of the risk of overdistention at the same time. The present study involves data from our ongoing registry for respiratory mechanics (ClinicalTrials.gov identifier: NCT02623192 . Registered 30 July 2015).

Continuous Blood Pressure Monitoring in Daily Life

NASA Astrophysics Data System (ADS)

Lopez, Guillaume; Shuzo, Masaki; Ushida, Hiroyuki; Hidaka, Keita; Yanagimoto, Shintaro; Imai, Yasushi; Kosaka, Akio; Delaunay, Jean-Jacques; Yamada, Ichiro

Continuous monitoring of blood pressure in daily life could improve early detection of cardiovascular disorders, as well as promoting healthcare. Conventional ambulatory blood pressure monitoring (ABPM) equipment can measure blood pressure at regular intervals for 24 hours, but is limited by long measuring time, low sampling rate, and constrained measuring posture. In this paper, we demonstrate a new method for continuous real-time measurement of blood pressure during daily activities. Our method is based on blood pressure estimation from pulse wave velocity (PWV) calculation, which formula we improved to take into account changes in the inner diameter of blood vessels. Blood pressure estimation results using our new method showed a greater precision of measured data during exercise, and a better accuracy than the conventional PWV method.

In situ measurement of soil moisture and pore-water pressures in an 'incipient' landslide: Lake Tutira, New Zealand.

PubMed

Hawke, Richard; McConchie, Jack

2011-02-01

The immediate cost of shallow regolith landslides in New Zealand has been estimated to exceed US$33M annually. Since the majority of these landslides occur during prolonged wet conditions, or intense rainstorms, moisture conditions are a critical control. The nature, dynamics, and character of soil moisture conditions, and the piezometric response to rainfall, have been recorded within an 'incipient' landslide for more than 5 years. The study site, on pastoral hill country within the Lake Tutira catchment in northern Hawkes Bay, is typical of large areas of New Zealand episodically affected by extensive landsliding. Detailed continuous measurements show that both the soil moisture and piezometric response within the regolith are highly storm- and site-specific. The development of positive pore pressures is infrequent; they form only during intense rainstorms, and persist for a short time. The hydraulic response of the soil is primarily a function of storm characteristics, but this response can be modified by antecedent moisture conditions, topographic position, and heterogeneity of soil properties. Stability analysis shows that most slopes in the study area are significantly steeper than can be explained by the frictional strength of the regolith. Measured hydraulic conditions also show that positive pore-water pressures alone do not trigger slope instability. A recent slope failure followed a period of extremely high antecedent moisture conditions, and occurred when maximum soil moisture conditions, though not pore-water pressures, were recorded. Increased moisture content of the regolith reduces matric tension, and therefore effective cohesion of the soil. This cohesion is critical to maintaining stability of the regolith on these slopes. Copyright © 2009 Elsevier Ltd. All rights reserved.

Noninvasive Ventilation During Immediate Postoperative Period in Cardiac Surgery Patients: Systematic Review and Meta-Analysis

PubMed Central

Pieczkoski, Suzimara Monteiro; Margarites, Ane Glauce Freitas; Sbruzzi, Graciele

2017-01-01

Objective To verify the effectiveness of noninvasive ventilation compared to conventional physiotherapy or oxygen therapy in the mortality rate and prevention of pulmonary complications in patients during the immediate postoperative period of cardiac surgery. Methods Systematic review and meta-analysis recorded in the International Prospective Register of Ongoing Systematic Reviews (number CRD42016036441). The research included the following databases: MEDLINE, Cochrane Central, PEDro, LILACS and manual search of the references of studies published until March 2016. The review included randomized controlled trials with patients during the immediate postoperative period of cardiac surgery, which compared the use of noninvasive ventilation, BiLevel modes, continuous positive airway pressure, intermittent positive pressure breathing and positive pressure ventilation with conventional physiotherapy or oxygen therapy, and assessed the mortality rate, occurrence of pulmonary complications (atelectasis, pneumonia, acute respiratory failure, hypoxemia), reintubation rate, ventilation time, time spent in the intensive care unit (ICU), length of hospital stay and partial pressure of oxygen. Results Among the 479 selected articles, ten were included in the systematic review (n=1050 patients) and six in the meta-analysis. The use of noninvasive ventilation did not significantly reduce the risk for atelectasis (RR: 0.60; CI95% 0.28-1.28); pneumonia (RR: 0.20; CI95% 0.04-1.16), reintubation rate (RR: 0.51; CI95%: 0.15-1.66), and time spent in the ICU (-0.04 days; CI95%: -0.13; 0.05). Conclusion Prophylactic noninvasive ventilation did not significantly reduce the occurrence of pulmonary complications such as atelectasis, pneumonia, reintubation rate and time spent in the ICU. The use is still unproven and new randomized controlled trials should be carried out. PMID:28977203

Therapy for sleep hypoventilation and central apnea syndromes.

PubMed

Selim, Bernardo J; Junna, Mithri R; Morgenthaler, Timothy I

2012-10-01

• Primary Central Sleep Apnea (CSA): We would recommend a trial of Positive Airway Pressure (PAP), acetazolamide, or zolpidem based on thorough consideration of risks and benefits and incorporation of patient preferences.• Central Sleep Apnea Due to Cheyne-Stokes Breathing Pattern in Congestive Heart Failure (CSR-CHF): We would recommend PAP devices such as continuous positive airway pressure (CPAP) or adaptive servo-ventilation (ASV) to normalize sleep-disordered breathing after optimizing treatment of heart failure. Oxygen may also be an effective therapy. Acetazolamide and theophylline may be considered if PAP or oxygen is not effective.• Central Sleep Apnea due to High-Altitude Periodic Breathing: We would recommend descent from altitude or supplemental oxygen. Acetazolamide may be used when descent or oxygen are not feasible, or in preparation for ascent to high altitude. Slow ascent may be preventative.• Central Sleep Apnea due to Drug or Substance: If discontinuation or reduction of opiate dose is not feasible or effective, we would recommend a trial of CPAP, and if not successful, treatment with ASV. If ASV is ineffective or if nocturnal hypercapnia develops, bilevel positive airway pressure-spontaneous timed mode (BPAP-ST) is recommended.• Obesity hypoventilation syndrome: We would recommend an initial CPAP trial. If hypoxia or hypercapnia persists on CPAP, BPAP, BPAP-ST or average volume assured pressure support (AVAPS™) is recommended. Tracheostomy with nocturnal ventilation should be considered when the above measures are not effective. Weight loss may be curative.• Neuromuscular or chest wall disease: We would recommend early implementation of BPAP-ST based on thorough consideration of risks and benefits and patient preferences. AVAPS™ may also be considered. We recommend close follow up due to disease progression.

Novel Positional Devices for the Treatment of Positional Obstructive Sleep Apnea, and How This Relates to Sleep Surgery.

PubMed

Ravesloot, Madeline J L; Benoist, Linda; van Maanen, Peter; de Vries, Nico

2017-01-01

If untreated, obstructive sleep apnea (OSA) develops as a gradual progressive disease. In the early stage of the disease most patients with OSA are positional. The archetypical patient might progress from simple positional snoring via positional early-stage mild disease to less positional moderate and finally nonpositional severe OSA. At first, the apnea-hypopnea index (AHI) is high only in the supine position, and later is high in all sleeping positions. The phenomenon is reversible. After partial effective treatment, patients with severe OSA can reverse to less severe positional OSA or, in other words, the AHI drops more in the lateral position than in supine position. This has been shown for palatal surgery, multilevel surgery, bimaxillary osteotomies, and bariatric surgery. The absence or presence of positional dependency has a great influence on sleep surgery. First, the results of sleep surgery might be worse in positional patients. Second, the addition of positional therapy to sleep surgery might improve the overall outcome and, as such, enhance the indication of sleep surgery as an alternative to continuous positive airway pressure and mandibular advancement device treatment. © 2017 S. Karger AG, Basel.

A hazard of the Intraflo continuous flush system.

PubMed

Schwartz, A J; Stoner, B B; Jobes, D R

1977-01-01

Patency of pressure sensing systems can be provided by the Intraflow Continuous Flush System (Sorenson Research Company, Salt Lake City, UT 84115). This device allows continuous flow of flush solution through a regulatory valve while preventing transmission of the high pressure of the flush solution. The case presented describes the recognition of a false elevation of a monitored pressure secondary to the malfunction of the Intraflo regulatory valve. Elimination of the flush solution high pressure during monitoring prevents inappropriate data collection.

Subjective assessment of simulated helicopter blade-slap noise

NASA Technical Reports Server (NTRS)

Lawton, B. W.

1976-01-01

The effects of several characteristics of helicopter blade slap upon human annoyance are examined. Blade slap noise was simulated by using continuous and impulsive noises characterized by five parameters: The number of sine waves in a single impulse; the frequency of the sine waves; the impulse repetition frequency; the sound pressure level (SPL) of the continuous noise; and the idealized crest factor of the impulses. Ten second samples of noise were synthesized with each of the five parameters at representative levels. The annoyance of each noise was judged by 40 human subjects. Analysis of the subjective data indicated that each of the five parameters had a statistically significant effect upon the annoyance judgments. The impulse crest factor and SPL of the continuous noise had very strong positive relationships with annoyance. The other parameters had smaller, but still significant, effects upon the annoyance judgments.

Comparison of the upper airway dynamics of oronasal and nasal masks with positive airway pressure treatment using cine magnetic resonance imaging.

PubMed

Ebben, Matthew R; Milrad, Sara; Dyke, Jonathan P; Phillips, C Douglas; Krieger, Ana C

2016-03-01

It is known that oronasal masks are not as effective at opening the upper airway compared to nasal only continuous positive airway pressure (CPAP) masks in patients with sleep-disordered breathing. However, the physiological mechanism for this difference in efficacy is not known; although, it has been hypothesized to involve the retroglossal and/or retropalatal region of the upper airway. The objective of this study was to investigate differences in retroglossal and retropalatal anterior-posterior space with the use of oronasal vs. nasal CPAP masks using real-time cine magnetic resonance imaging (cMRI). Ten subjects (eight men, two women) with obstructive sleep apnea (OSA) were given cMRI with both nasal and oronasal CPAP masks. Each subject was imaged with each interface at pressures of 5, 10, and 15 cm of H2O, while in the supine position along the sagittal plane. The oronasal mask produced significantly less airway opening in the retropalatal region of the upper airway compared to the nasal mask interface. During exhalation, mask style had a significant effect on anterior-posterior distance p = 0.016. No differences were found in the retroglossal region between mask styles. Our study confirmed previous findings showing differences in treatment efficacy between oronasal and nasal mask styles. We have shown anatomic evidence that the nasal mask is more effective in opening the upper airway compared to the oronasal mask in the retropalatal region.

Comparison of the Upper Airway Dynamics of Oronasal and Nasal Masks with Positive Airway Pressure Treatment using cine Magnetic Resonance Imaging

PubMed Central

Ebben, Matthew R.; Milrad, Sara; Dyke, Jonathan P.; Phillips, C. Douglas; Krieger, Ana C.

2016-01-01

Purpose It is known that oronasal masks are not as effective at opening the upper airway compared to nasal only continuous positive airway pressure (CPAP) masks in patients with sleep disordered breathing. However, the physiological mechanism for this difference in efficacy is not known; although, it has been hypothesized to involve the retroglossal and/or retropalatal region of the upper airway. The objective of this study was to investigate differences in retroglossal and retropalatal anterior-posterior space with the use of oronasal vs. nasal CPAP masks using real-time cine Magnetic Resonance Imaging (cMRI). Methods 10-Subjects (8-men, 2-women) with obstructive sleep apnea (OSA) were given cMRI with both nasal and oronasal CPAP masks. Each subject was imaged with each interface at pressures of 5, 10 and 15 cm of H2O, while in the supine position along the sagittal plane. Results The oronasal mask produced significantly less airway opening in the retropalatal region of the upper airway compared to the nasal mask interface. During exhalation, mask style had a significant effect on anterior-posterior distance p=0.016. No differences were found in the retroglossal region between mask styles. Conclusions Our study confirmed previous findings showing differences in treatment efficacy between oronasal and nasal mask styles. We have shown anatomic evidence that the nasal mask is more effective in opening the upper airway compared to the oronasal mask in the retropalatal region. PMID:25924934

Initial stabilisation of preterm infants: a new resuscitation system with low imposed work of breathing for use with face mask or nasal prongs.

PubMed

Donaldsson, Snorri; Drevhammar, Thomas; Taittonen, Leena; Klemming, Stina; Jonsson, Baldvin

2017-05-01

T-piece resuscitation systems are pressure unstable and have high imposed work of breathing (iWOB). Pressure stable respiratory support with low iWOB might improve outcome. We have developed a new resuscitation system that can be used with nasal prongs or face mask. The aim of the study was to describe the in vitro performance of the new system and to perform a clinical feasibility trial of initial stabilisation of preterm infants. A mechanical lung model was used to determine iWOB at increasing levels of continuous positive airway pressure (CPAP). The feasibility trial included 36 infants (27-34 weeks of gestation), who were randomised into three groups (T-piece, new system with face mask or new system with prongs). Collected data included problems with usage, safety, time to stable breathing, need for positive pressure ventilation and intubation. In the mechanical lung model, the new system reduced iWOB with 91.5% (mask) and 86.6% (medium prongs) compared with Neopuff (4 cm CPAP, p<0.001). Informed consent was obtained from 45 patients, 39 were randomised and 36 needed support. Randomisation resulted in an imbalance: The group of new system infants had lower gestational age compared with the T-piece group. Thirteen patients needed positive pressure ventilation (median 20 cm H 2 O). One infant was intubated. The study did not reveal problems with the equipment or safety. Compared with T-piece systems, the new system had a marked reduction in iWOB in bench tests. The feasibility trial did not reveal problems with usability or safety. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

40 CFR 147.1803 - Existing Class I and III wells authorized by rule-maximum injection pressure.

Code of Federal Regulations, 2010 CFR

2010-07-01

... authorized by rule-maximum injection pressure. 147.1803 Section 147.1803 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) STATE, TRIBAL, AND EPA-ADMINISTERED...—maximum injection pressure. The owner or operator shall limit injection pressure to the lesser of: (a) A...

System and method for slurry handling

DOEpatents

Steele, Raymond Douglas; Oppenheim, Judith Pauline

2015-12-29

A system includes a slurry depressurizing system that includes a liquid expansion system configured to continuously receive a slurry at a first pressure and continuously discharge the slurry at a second pressure. For example, the slurry depressurizing system may include an expansion turbine to expand the slurry from the first pressure to the second pressure.

Ontogenetic shifts of heart position in snakes.

PubMed

Lillywhite, Harvey B; Lillywhite, Steven M

2017-08-01

Heart position relative to total body length (TL) varies among snakes, with anterior hearts in arboreal species and more centrally located hearts in aquatic or ground-dwelling species. Anterior hearts decrease the cardiac work associated with cranial blood flow and minimize drops in cranial pressure and flow during head-up climbing. Here, we investigate whether heart position shifts intraspecifically during ontogenetic increases in TL. Insular Florida cottonmouth snakes, Agkistrodon conanti, are entirely ground-dwelling and have a mean heart position that is 33.32% TL from the head. In contrast, arboreal rat snakes, Pantherophis obsoleta, of similar lengths have a mean heart position that is 17.35% TL from the head. In both species, relative heart position shifts craniad during ontogeny, with negative slopes = -.035 and -.021% TL/cm TL in Agkistrodon and Pantherophis, respectively. Using a large morphometric data set available for Agkistrodon (N = 192 individuals, 23-140 cm TL), we demonstrate there is an anterior ontogenetic shift of the heart position within the trunk (= 4.56% trunk length from base of head to cloacal vent), independent of head and tail allometry which are both negative. However, in longer snakes > 100 cm, the heart position reverses and shifts caudally in longer Agkistrodon but continues toward the head in longer individuals of Pantherophis. Examination of data sets for two independent lineages of fully marine snakes (Acrochordus granulatus and Hydrophis platurus), which do not naturally experience postural gravity stress, demonstrate both ontogenetic patterns for heart position that are seen in the terrestrial snakes. The anterior migration of the heart is greater in the terrestrial species, even if TL is standardized to that of the longer P. obsoleta, and compensates for about 5 mmHg gravitational pressure head if they are fully upright. © 2017 Wiley Periodicals, Inc.

Standing orthostatic blood pressure measurements cannot be replaced by sitting measurements.

PubMed

Breeuwsma, Anna C; Hartog, Laura C; Kamper, Adriaan M; Groenier, Klaas H; Bilo, Henk Jg; Kleefstra, Nanne; Van Hateren, Kornelis Jj

2017-08-01

As many elderly patients are not able to stand for several minutes, sitting orthostatic blood pressure (BP) measurements are sometimes used as an alternative. We aimed to investigate the difference in BP response and orthostatic hypotension (OH) prevalence between the standard postural change to the sitting and the standing position in a cross-sectional observational study. BP was measured with a continuous BP measurement device during two postural changes, from supine to the sitting and from supine to the standing position. Linear mixed models were used to investigate the differences in changes (Δ) of systolic BP (SBP) and diastolic BP (DBP) between the two postural changes. The prevalence and the positive and negative proportions of agreement of OH were calculated of the two postural changes. One hundred and four patients with a mean age of 69 years were included. ΔSBP was significantly larger in the standing position compared with the sitting between 0 and 44 s. ΔDBP was significantly larger in the sitting position compared with the standing 75-224 s after postural change. The prevalence of OH was 66.3% (95% confidence interval (CI) 57.2, 75.4) in the standing position and 67.3% (95% CI 58.3, 76.3) in the sitting position. The positive proportion of agreement was 74.8% and the negative proportion of agreement was 49.3%. A clear difference was seen in BP response between the two postural changes. Although no significant difference in prevalence of OH was observed, the positive and negative proportion of agreement of the prevalence of OH were poor to moderate, which indicates a different outcome between both postural changes.

PSP: rapid identification of orthologous coding genes under positive selection across multiple closely related prokaryotic genomes.

PubMed

Su, Fei; Ou, Hong-Yu; Tao, Fei; Tang, Hongzhi; Xu, Ping

2013-12-27

With genomic sequences of many closely related bacterial strains made available by deep sequencing, it is now possible to investigate trends in prokaryotic microevolution. Positive selection is a sub-process of microevolution, in which a particular mutation is favored, causing the allele frequency to continuously shift in one direction. Wide scanning of prokaryotic genomes has shown that positive selection at the molecular level is much more frequent than expected. Genes with significant positive selection may play key roles in bacterial adaption to different environmental pressures. However, selection pressure analyses are computationally intensive and awkward to configure. Here we describe an open access web server, which is designated as PSP (Positive Selection analysis for Prokaryotic genomes) for performing evolutionary analysis on orthologous coding genes, specially designed for rapid comparison of dozens of closely related prokaryotic genomes. Remarkably, PSP facilitates functional exploration at the multiple levels by assignments and enrichments of KO, GO or COG terms. To illustrate this user-friendly tool, we analyzed Escherichia coli and Bacillus cereus genomes and found that several genes, which play key roles in human infection and antibiotic resistance, show significant evidence of positive selection. PSP is freely available to all users without any login requirement at: http://db-mml.sjtu.edu.cn/PSP/. PSP ultimately allows researchers to do genome-scale analysis for evolutionary selection across multiple prokaryotic genomes rapidly and easily, and identify the genes undergoing positive selection, which may play key roles in the interactions of host-pathogen and/or environmental adaptation.

Sleeping Well Trial: Increasing the effectiveness of treatment with continuous positive airway pressure using a weight management program in overweight adults with obstructive sleep apnoea-A stepped wedge randomised trial protocol.

PubMed

Truby, Helen; Edwards, Bradley A; O'Driscoll, Denise M; Young, Alan; Ghazi, Ladan; Bristow, Claire; Roem, Kerryn; Bonham, Maxine P; Murgia, Chiara; Day, Kaitlin; Haines, Terry P; Hamilton, Garun S

2018-05-24

The majority of adults diagnosed with obstructive sleep apnoea (OSA) are overweight or obese. Continuous positive airway pressure (CPAP) is the most common effective therapy for OSA. However, adherence declines over time with only 50% of patients prescribed CPAP continuing to use it long term. Furthermore, a recent prospective analysis indicated that those more adherent with CPAP therapy have enhanced weight gain trajectories which in turn may negatively impact their OSA. The Sleeping Well Trial aims to establish whether the timing of starting a lifestyle weight loss intervention impacts on weight trajectory in those with moderate-severe OSA treated at home with CPAP, while testing the potential for smart phone technology to improve adherence with lifestyle interventions. A stepped wedge design with randomisation of individuals from 1 to 6 months post-enrolment, with 5 months of additional prospective follow up after completion of the stepped wedge. This design will investigate the effect of the 6-month lifestyle intervention on people undergoing CPAP on body weight, body composition and health-related quality of life. This trial tests whether the timing of supporting the patient through a weight loss intervention is important in obtaining the maximum benefit of a lifestyle change and CPAP usage, and identify how best to support patients through this critical period. The protocol (v1) is registered prospectively with the International Clinical Trials Registry (CTR) ACTRN12616000203459 (public access). Any amendments to protocol will be documented via the CTR. Recruitment commenced in March 2016 with data collection scheduled to finish by May 2018. © 2018 Dietitians Association of Australia.

Nasal Jet-CPAP (variable flow) versus Bubble-CPAP in preterm infants with respiratory distress: an open label, randomized controlled trial.

PubMed

Bhatti, A; Khan, J; Murki, S; Sundaram, V; Saini, S S; Kumar, P

2015-11-01

To compare the failure rates between Jet continuous positive airway pressure device (J-CPAP-variable flow) and Bubble continuous positive airway device (B-CPAP) in preterm infants with respiratory distress. Preterm newborns <34 weeks gestation with onset of respiratory distress within 6 h of life were randomized to receive J-CPAP (a variable flow device) or B-CPAP (continuous flow device). A standardized protocol was followed for titration, weaning and removal of CPAP. Pressure was monitored close to the nares in both the devices every 6 hours and settings were adjusted to provide desired CPAP. The primary outcome was CPAP failure rate within 72 h of life. Secondary outcomes were CPAP failure within 7 days of life, need for surfactant post-randomization, time to CPAP failure, duration of CPAP and complications of prematurity. An intention to treat analysis was done. One-hundred seventy neonates were randomized, 80 to J-CPAP and 90 to B-CPAP. CPAP failure rates within 72 h were similar in infants who received J-CPAP and in those who received B-CPAP (29 versus 21%; relative risks 1.4 (0.8 to 2.3), P=0.25). Mean (95% confidence intervals) time to CPAP failure was 59 h (54 to 64) in the Jet CPAP group in comparison with 65 h (62 to 68) in the Bubble CPAP group (log rank P=0.19). All other secondary outcomes were similar between the two groups. In preterm infants with respiratory distress starting within 6 h of life, CPAP failure rates were similar with Jet CPAP and Bubble CPAP.

Smartphone-based Continuous Blood Pressure Measurement Using Pulse Transit Time.

PubMed

Gholamhosseini, Hamid; Meintjes, Andries; Baig, Mirza; Linden, Maria

2016-01-01

The increasing availability of low cost and easy to use personalized medical monitoring devices has opened the door for new and innovative methods of health monitoring to emerge. Cuff-less and continuous methods of measuring blood pressure are particularly attractive as blood pressure is one of the most important measurements of long term cardiovascular health. Current methods of noninvasive blood pressure measurement are based on inflation and deflation of a cuff with some effects on arteries where blood pressure is being measured. This inflation can also cause patient discomfort and alter the measurement results. In this work, a mobile application was developed to collate the PhotoPlethysmoGramm (PPG) waveform provided by a pulse oximeter and the electrocardiogram (ECG) for calculating the pulse transit time. This information is then indirectly related to the user's systolic blood pressure. The developed application successfully connects to the PPG and ECG monitoring devices using Bluetooth wireless connection and stores the data onto an online server. The pulse transit time is estimated in real time and the user's systolic blood pressure can be estimated after the system has been calibrated. The synchronization between the two devices was found to pose a challenge to this method of continuous blood pressure monitoring. However, the implemented continuous blood pressure monitoring system effectively serves as a proof of concept. This combined with the massive benefits that an accurate and robust continuous blood pressure monitoring system would provide indicates that it is certainly worthwhile to further develop this system.

Development Specification for RV-346/348 Positive Pressure Relief Valves (PPRV)

NASA Technical Reports Server (NTRS)

Ralston, Russell L.

2017-01-01

This specification establishes the requirements for design, performance, safety, testing, and manufacture of the RV-346 and RV-348, Positive Pressure Relief Valve (PPRV) as part of the Advanced Extravehicular Mobility Unit (EMU)(AEMU) Portable Life Support System (PLSS). The RV-346 serves as the Positive Pressure Relief Valve (PPRV), and the RV-348 serves as the Secondary Positive Pressure Relief Valve (SPPRV).

Physiological Effects of Positive Pressure Ventilation.

DTIC Science & Technology

1992-05-01

function in the patient with respiratory failure . In R. R. Kirby, M. J. Banner, & J. B. Downs (Eds.), Clinical Applications of Ventilatory Su2Rort (pp. 301...G., Blehschmidt, N. G., & Linder, W. J. (1990). Positive-pressure ventilation with positive end-expiratory pressure and atrial natriuretic peptide ...Acute Resniratorv Failure . New York: Churchill Livingstone. Ventilation 1 Physiological Effects of Positive Pressure Ventilation Dennis L. Oakes, RN, BSN

Controversies in perioperative anesthetic management of the morbidly obese: I am a surgeon, why should I care?

PubMed

Sinha, Ashish C; Singh, Preet Mohinder

2015-05-01

Over the last four decades, as the rates of obesity have increased, so have the challenges associated with its anesthetic management. In the present review, we discuss perioperative anesthesia management issues that are modifiable by the early involvement of the surgical team. We sum up available evidence or expert opinion on issues like patient positioning, postoperative analgesia, and the effect of continuous positive airway pressure (CPAP) ventilation on surgical anastomosis. We also address established predictors of higher perioperative risk and suggest possible management strategies and concerns of obese patients undergoing same day procedures. Finally, a generalized pharmacological model relevant to altered pharmacokinetics in these patients is presented.

A randomised controlled trial of flow driver and bubble continuous positive airway pressure in preterm infants in a resource-limited setting.

PubMed

Mazmanyan, P; Mellor, K; Doré, C J; Modi, N

2016-01-01

The variable-flow flow driver (FD; EME) and continuous-flow bubble (Fisher-Paykel) continuous positive airway pressure (CPAP) systems are widely used. As these differ in cost and technical requirements, determining comparative efficacy is important particularly where resources are limited. We performed a randomised, controlled, equivalence trial of CPAP systems. We specified the margin of equivalence as 2 days. We analysed binary variables by logistical regression adjusted for gestation, and log transformed continuous variables by multiple linear regression adjusted for gestation, sex and antenatal steroids. A neonatal unit with no blood gas analyser or surfactant availability and limited X-ray and laboratory facilities Neonates <37 weeks of gestation. We provided CPAP at delivery followed by randomisation to FD or bubble (B). Primary outcome included total days receiving CPAP; secondary outcomes included days receiving CPAP, supplemental oxygen, ventilation, death, pneumothorax and nasal excoriation. We randomised 125 infants (B 66, FD 59). Differences in infant outcomes on B and FD were not statistically significant. The median (range) for CPAP days for survivors was B 0.8 (0.04 to 17.5), FD 0.5 (0.04 to 5.3). B:FD (95% CI) ratios were CPAP days 1.3 (0.9 to 2.1), CPAP plus supplementary oxygen days 1.2 (0.7 to 1.9). B:FD (95% CI) ORs were death 2.3 (0.2 to 28), ventilation 2.1 (0.5 to 9), nasal excoriation 1.2 (0.2 to 8) and pneumothorax 2.4 (0.2 to 26). In a resource-limited setting we found B CPAP equivalent to FD CPAP in the total number of days receiving CPAP within a margin of 2 days. ISRCTN22578364. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Endotracheal cuff pressure changes with change in position in neurosurgical patients.

PubMed

Athiraman, UmeshKumar; Gupta, Rohit; Singh, Georgene

2015-01-01

Placement of a cuffed endotracheal tube for the administration of general anesthesia is routine. The cuff of the endotracheal tube is inflated with air to achieve an adequate seal to prevent micro-aspiration. Over inflation of the cuff can decrease the mucosal perfusion, leading to pressure necrosis and nerve palsies. Inadequate seal can lead to micro aspiration. So the cuff pressure has to be monitored and kept within the prescribed limits of 20-30 cms of water. To observe the effect of different positions on the endotracheal cuff pressure in patients undergoing neurosurgical procedures. This is an observational study conducted on 70 patients undergoing neurosurgical procedures in various positions. After intubation, the cuff pressure was checked with a cuff pressure manometer, Endotest (Teleflex Medical, Rush) and adjusted to be within the allowable pressure limits as is the routine practice. The cuff pressure was checked again at three time points after achieving the final position with the head on pins, at the end of the procedure and before extubation. Various factors such as the age, position, duration of surgery were studied. There were no major complications like aspiration, stridor or hoarseness of voice post extubation in any of the patients. A significant decline in the cuff pressures were noted from the initial supine position to extubation (P < .001) in the supine group. Also a significant decline in the cuff pressures were found in the prone group from their initial intubated supine position to all the other three corresponding time points namely after final positioning (P < .001), at the end of the procedure (P < .001) and before extubation (P < .001). Cuff pressure has to be checked after achieving the final positioning of the patient and adjusted to the prescribed limits to prevent micro aspiration.

Contrastive Analysis and Research on Negative Pressure Beam Tube System and Positive Pressure Beam Tube System for Mine Use

NASA Astrophysics Data System (ADS)

Wang, Xinyi; Shen, Jialong; Liu, Xinbo

2018-01-01

Against the technical defects of universally applicable beam tube monitoring system at present, such as air suction in the beam tube, line clogging, long sampling time, etc., the paper analyzes the current situation of the spontaneous combustion fire disaster forecast of mine in our country and these defects one by one. On this basis, the paper proposes a research thought that improving the positive pressure beam tube so as to substitute the negative pressure beam tube. Then, the paper introduces the beam tube monitoring system based on positive pressure technology through theoretical analysis and experiment. In the comparison with negative pressure beam tube, the paper concludes the advantage of the new system and draws the conclusion that the positive pressure beam tube is superior to the negative pressure beam tube system both in test result and test time. At last, the paper proposes prospect of the beam tube monitoring system based on positive pressure technology.

Glaucoma and its association with obstructive sleep apnea: A narrative review

PubMed Central

Chaitanya, Aditya; Pai, Vijaya H.; Mohapatra, Aswini Kumar; Ve, Ramesh S.

2016-01-01

Obstructive sleep apnea (OSA) is one of the systemic risk factors for glaucoma which causes irreversible visual field (VF) damage. We reviewed the published data of all types of studies on the association between these two conditions and papers regarding functional and structural changes related to glaucomatous damage using Scopus, web of science, and PubMed databases. There is evidence that the prevalence of glaucoma is higher in OSA patients, which independent of intraocular pressure (IOP). Studies have reported thinning of retinal nerve fiber layer (RNFL), alteration of optic nerve head, choroidal and macular thickness, and reduced VF sensitivity in patients of OSA with no history glaucoma. A negative correlation of apnea-hypopnea index with RNFL and VF indices has been described in some studies. Raised IOP was noted which is possibly related to obesity, supine position during sleep, and raised intracranial pressure. Diurnal fluctuations of IOP show more variations in OSA patients before and after continuous positive airway pressure (CPAP) therapy when compared with the normal cases. The vascular factors behind the pathogenesis include recurrent hypoxia with increased vascular resistance, oxidative stress damage to the optic nerve. In conclusion, comprehensive glaucoma evaluation should be recommended in patients with OSA and should also periodically monitor IOP during CPAP treatment which may trigger the progression of glaucomatous damage. PMID:27843225

Unsteady separation in sharp fin-induced shock wave/turbulent boundary layer interaction at Mach 5

NASA Technical Reports Server (NTRS)

Schmisseur, J. D.; Dolling, D. S.

1992-01-01

Fluctuating wall-pressure measurements are made in shock-wave/turbulent-boundary-layer interactions generated by sharp/unswept fins at angles of attack of 16, 18, 20, 22, 24, 26, and 28 degrees at Mach 5. The experiment was conducted under approximately adiabatic wall temperature conditions. The mean and rms pressure distributions can be collapsed in conical coordinates. The wall-pressure signal near separation is intermittent for all angles of attack (16-28 deg) and is qualitatively similar to that measured in unswept flows. However, the shock frequencies are higher - about 5 kHz compared to 0.5-1 kHz. Over the range of sweepbacks examined, from 25-55 deg, the spectral content of the fluctuating pressures does not change. Thus, the increase in separation-shock frequency from 1 to 5 kHz occurs at lower interaction sweepback and is not a continuous process with increasing sweepback. Power spectra at the position of maximum rms in the intermittent region for interactions in different incoming boundary layers have the same center frequency. The maximum rms in the intermittent region correlates with interaction sweepback, not with overall inviscid pressure rise.

Sleep-Related Painful Erections in a Patient With Obstructive Sleep Apnea Syndrome.

PubMed

Abouda, Maher; Jomni, Taieb; Yangui, Ferdaws; Charfi, Mohamed Ridha; Arnulf, Isabelle

2016-01-01

Sleep-related painful erection (SRPE) is a rare sleep disorder characterized by recurrent, painful penile erections occurring when awakening from rapid eye movement sleep, while erections are painless during wakefulness. Almost 35 cases have been reported worldwide, and only two of them had an associated obstructive sleep apnea syndrome (OSAS). We report a new case of a 61-year-old man suffering from SRPE associated with OSAS. The adequate treatment of respiratory events with continuous positive airway pressure did not alleviate the SRPE symptoms and excessive daytime sleepiness. The SRPE diagnosis was made by polysomnography coupled with video surveillance when the patient was referred to the sleep laboratory for residual excessive daytime sleepiness. The patient had 2-4 episodes of SRPE/night. Beta-blocker did not alleviate the SRPE, but a transient improvement was noted when the patient was treated with paroxetine. In contrast with the two previously published cases of SRPE plus OSAS, continuous positive airway treatment did not improve SRPE symptoms in our patient.

Relationships among cardiovascular, muscular, and oxytocin responses during human sexual activity.

PubMed

Carmichael, M S; Warburton, V L; Dixen, J; Davidson, J M

1994-02-01

To determine the psychophysiological correlates of hormonal response during sexual activity, systolic blood pressure (SBP), anal electromyography (EMG), and anal photoplethysmography (APG) were monitored continuously throughout testing in 13 women and 10 men. Each subject completed two or more tests of self-stimulation to 5 min beyond orgasm. Blood samples were obtained continuously for measurement of oxytocin (OT) levels. In both men and women, very high positive correlations were observed between the percentage change in levels from baseline through orgasm of: OT and SBP; OT and EMG intensity prior to and during orgasm; APG and EMG. The number of anal contractions and duration of orgasm were also highly correlated. Two patterns of orgasm were defined by the presence or absence of a quiescent period between orgasmic contractions. EMG and APG amplitudes correlated with the pattern of orgasm. Subjective orgasm intensity correlated significantly with increased levels of OT in multiorgasmic women only. The positive correlations between measures are consistent with a possible functional role for OT in human sexual response.

Age-specific association between blood pressure and vascular and non-vascular chronic diseases in 0·5 million adults in China: a prospective cohort study.

PubMed

Lacey, Ben; Lewington, Sarah; Clarke, Robert; Kong, Xiang Ling; Chen, Yiping; Guo, Yu; Yang, Ling; Bennett, Derrick; Bragg, Fiona; Bian, Zheng; Wang, Shaojie; Zhang, Hua; Chen, Junshi; Walters, Robin G; Collins, Rory; Peto, Richard; Li, Liming; Chen, Zhengming

2018-06-01

The age-specific association between blood pressure and vascular disease has been studied mostly in high-income countries, and before the widespread use of brain imaging for diagnosis of the main stroke types (ischaemic stroke and intracerebral haemorrhage). We aimed to investigate this relationship among adults in China. 512 891 adults (59% women) aged 30-79 years were recruited into a prospective study from ten areas of China between June 25, 2004, and July 15, 2008. Participants attended assessment centres where they were interviewed about demographic and lifestyle characteristics, and their blood pressure, height, and weight were measured. Incident disease was identified through linkage to local mortality records, chronic disease registries, and claims to the national health insurance system. We used Cox regression analysis to produce adjusted hazard ratios (HRs) relating systolic blood pressure to disease incidence. HRs were corrected for regression dilution to estimate associations with long-term average (usual) systolic blood pressure. During a median follow-up of 9 years (IQR 8-10), there were 88 105 incident vascular and non-vascular chronic disease events (about 90% of strokes events were diagnosed using brain imaging). At ages 40-79 years (mean age at event 64 years [SD 9]), usual systolic blood pressure was continuously and positively associated with incident major vascular disease throughout the range 120-180 mm Hg: each 10 mm Hg higher usual systolic blood pressure was associated with an approximately 30% higher risk of ischaemic heart disease (HR 1·31 [95% CI 1·28-1·34]) and ischaemic stroke (1·30 [1·29-1·31]), but the association with intracerebral haemorrhage was about twice as steep (1·68 [1·65-1·71]). HRs for vascular disease were twice as steep at ages 40-49 years than at ages 70-79 years. Usual systolic blood pressure was also positively associated with incident chronic kidney disease (1·40 [1·35-1·44]) and diabetes (1·14 [1·12-1·15]). About half of all vascular deaths in China were attributable to elevated blood pressure (ie, systolic blood pressure >120 mm Hg), accounting for approximately 1 million deaths (<80 years of age) annually. Among adults in China, systolic blood pressure was continuously related to major vascular disease with no evidence of a threshold down to 120 mm Hg. Unlike previous studies in high-income countries, blood pressure was more strongly associated with intracerebral haemorrhage than with ischaemic stroke. Even small reductions in mean blood pressure at a population level could be expected to have a major impact on vascular morbidity and mortality. UK Wellcome Trust, UK Medical Research Council, British Heart Foundation, Cancer Research UK, Kadoorie Charitable Foundation, Chinese Ministry of Science and Technology, and the National Science Foundation of China. Copyright © 2018 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.

Therapeutic Strategies for Sleep Apnea in Hypertension and Heart Failure

PubMed Central

Noda, Akiko; Miyata, Seiko; Yasuda, Yoshinari

2013-01-01

Sleep-disordered breathing (SDB) causes hypoxemia, negative intrathoracic pressure, and frequent arousal, contributing to increased cardiovascular disease mortality and morbidity. Obstructive sleep apnea syndrome (OSAS) is linked to hypertension, ischemic heart disease, and cardiac arrhythmias. Successful continuous positive airway pressure (CPAP) treatment has a beneficial effect on hypertension and improves the survival rate of patients with cardiovascular disease. Thus, long-term compliance with CPAP treatment may result in substantial blood pressure reduction in patients with resistant hypertension suffering from OSAS. Central sleep apnea and Cheyne-Stokes respiration occur in 30–50% of patients with heart failure (HF). Intermittent hypoxemia, nocturnal surges in sympathetic activity, and increased left ventricular preload and afterload due to negative intrathoracic pressure all lead to impaired cardiac function and poor life prognosis. SDB-related HF has been considered the potential therapeutic target. CPAP, nocturnal O2 therapy, and adaptive servoventilation minimize the effects of sleep apnea, thereby improving cardiac function, prognosis, and quality of life. Early diagnosis and treatment of SDB will yield better therapeutic outcomes for hypertension and HF. PMID:23509623

Cuffless Blood Pressure Estimation Based on Data-Oriented Continuous Health Monitoring System

PubMed Central

Kawanaka, Haruki; Oguri, Koji

2017-01-01

Measuring blood pressure continuously helps monitor health and also prevent lifestyle related diseases to extend the expectancy of healthy life. Blood pressure, which is nowadays used for monitoring patient, is one of the most useful indexes for prevention of lifestyle related diseases such as hypertension. However, continuously monitoring the blood pressure is unrealistic because of discomfort caused by the tightening of a cuff belt. We have earlier researched the data-oriented blood pressure estimation without using a cuff. Remarkably, our blood pressure estimation method only uses a photoplethysmograph sensor. Therefore, the application is flexible for sensor locations and measuring situations. In this paper, we describe the implementation of our estimation method, the launch of a cloud system which can collect and manage blood pressure data measured by a wristwatch-type photoplethysmograph sensor, and the construction of our applications to visualize life-log data including the time-series data of blood pressure. PMID:28523074

Tissue-Informative Mechanism for Wearable Non-invasive Continuous Blood Pressure Monitoring

NASA Astrophysics Data System (ADS)

Woo, Sung Hun; Choi, Yun Young; Kim, Dae Jung; Bien, Franklin; Kim, Jae Joon

2014-10-01

Accurate continuous direct measurement of the blood pressure is currently available thru direct invasive methods via intravascular needles, and is mostly limited to use during surgical procedures or in the intensive care unit (ICU). Non-invasive methods that are mostly based on auscultation or cuff oscillometric principles do provide relatively accurate measurement of blood pressure. However, they mostly involve physical inconveniences such as pressure or stress on the human body. Here, we introduce a new non-invasive mechanism of tissue-informative measurement, where an experimental phenomenon called subcutaneous tissue pressure equilibrium is revealed and related for application in detection of absolute blood pressure. A prototype was experimentally verified to provide an absolute blood pressure measurement by wearing a watch-type measurement module that does not cause any discomfort. This work is supposed to contribute remarkably to the advancement of continuous non-invasive mobile devices for 24-7 daily-life ambulatory blood-pressure monitoring.

Provider Perceptions of Bubble Continuous Positive Airway Pressure and Barriers to Implementation in a Level III Neonatal Unit in South India.

PubMed

Atreya, Mihir R; Lorenz, John M; Narendran, Vivek

2018-05-31

Bubble continuous positive airway pressure (bCPAP) is a simple, safe, and cost-effective strategy to provide respiratory support to newborns with respiratory distress syndrome in resource-limited settings. To understand whether implementation of bCPAP, relative to other modes of respiratory support in the care of newborns with respiratory distress syndrome, increases positive attitudes about its potential for consistent and widespread use among providers in neonatal intensive care units (NICUs) of lower middle-income countries. Semistructured qualitative interviews with 14 healthcare providers, including 5 neonatal nurses, 2 respiratory therapists, 5 postgraduate trainees in pediatrics, and 2 attending physicians, were conducted at a level III NICU in south India where bCPAP had been in consistent use for 6 years. Interviews were transcribed and then coded and categorized using NVivo 10 Software (QSR International, Victoria, Australia). Categories that emerged from our data include (1) perceived indications, (2) learning curve, (3) perceived costs, (4) perceived shortages, and (5) barriers to use. Providers believed that bCPAP was easy to learn and that it helped empower neonatal nurses in decision-making process. Participants provided a nuanced perspective of cost-benefit associated with bCPAP and that it helped make optimal use of limited resources. Participants identified several barriers to the implementation of bCPAP. Providers of a level III NICU in a lower- to middle-income country viewed the use of bCPAP favorably. Addressing context-specific barriers will be important for the successful widespread implementation of bCPAP. Further research will need to focus on whether bCPAP can be safely implemented at level II NICUs.

Self-Efficacy and Short-Term Adherence to Continuous Positive Airway Pressure Treatment in Children.

PubMed

Xanthopoulos, Melissa S; Kim, Ji Young; Blechner, Michael; Chang, Ming-Yu; Menello, Mary Kate; Brown, Christina; Matthews, Edward; Weaver, Terri E; Shults, Justine; Marcus, Carole L

2017-07-01

Infants, children, and adolescents are increasingly being prescribed continuous positive airway pressure (CPAP) for treatment of obstructive sleep apnea syndrome (OSAS), yet adherence is often poor. The purpose of this study was to examine the relationship between caregiver and patient-reported health cognitions about CPAP prior to starting CPAP and CPAP adherence at 1 month. We hypothesized that greater caregiver-reported self-efficacy would be positively associated with CPAP adherence in children. We also evaluated patient-reported self-efficacy and caregiver- and patient-reported risk perception and outcome expectations as they related to adherence, as well as how demographic factors influenced these relationships. A pediatric modification of the Self-Efficacy Measure for Sleep Apnea Questionnaire was administered to children and adolescents with OSAS-prescribed CPAP and their caregivers during the clinical CPAP-initiation visit. The primary outcome variable for adherence was the average total minutes of CPAP usage across all days from the date that CPAP was initiated to 31 days later. Unadjusted ordinary least-square regression showed a significant association between caregiver-reported self-efficacy and adherence (p = .007), indicating that mean daily CPAP usage increased by 48.4 minutes when caregiver-reported self-efficacy increased by one point (95% confidence interval 13.4-83.4 minutes). No other caregiver- or patient-reported cognitive health variables were related to CPAP use. This study indicates that caregiver CPAP-specific self-efficacy is an important factor to consider when starting youth on CPAP therapy for OSAS. Employing strategies to improve caregiver self-efficacy, beginning at CPAP initiation, may promote CPAP adherence. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

The influence of systemic hemodynamics and oxygen transport on cerebral oxygen saturation in neonates after the Norwood procedure.

PubMed

Li, Jia; Zhang, Gencheng; Holtby, Helen; Guerguerian, Anne-Marie; Cai, Sally; Humpl, Tilman; Caldarone, Christopher A; Redington, Andrew N; Van Arsdell, Glen S

2008-01-01

Ischemic brain injury is an important morbidity in neonates after the Norwood procedure. Its relationship to systemic hemodynamic oxygen transport is poorly understood. Sixteen neonates undergoing the Norwood procedure were studied. Continuous cerebral oxygen saturation was measured by near-infrared spectroscopy. Continuous oxygen consumption was measured by respiratory mass spectrometry. Pulmonary and systemic blood flow, systemic vascular resistance, oxygen delivery, and oxygen extraction ratio were derived with measurements of arterial, and superior vena cava and pulmonary venous gases and pressures at 2- to 4-hour intervals during the first 72 hours in the intensive care unit. Mean cerebral oxygen saturation was 66% +/- 12% before the operation, reduced to 51% +/- 13% on arrival in the intensive care unit, and remained low during the first 8 hours; it increased to 56% +/- 9% at 72 hours, still significantly lower than the preoperative level (P < .05). Postoperatively, cerebral oxygen saturation was closely and positively correlated with systemic arterial pressure, arterial oxygen saturation, and arterial oxygen tension and negatively with oxygen extraction ratio (P < .0001 for all). Cerebral oxygen saturation was moderately and positively correlated with systemic blood flow and oxygen delivery (P < .0001 for both). It was weakly and positively correlated with pulmonary blood flow (P = .001) and hemoglobin (P = .02) and negatively correlated with systemic vascular resistance (P = .003). It was not correlated with oxygen consumption (P > .05). Cerebral oxygen saturation decreased significantly in neonates during the early postoperative period after the Norwood procedure and was significantly influenced by systemic hemodynamic and metabolic events. As such, hemodynamic interventions to modify systemic oxygen transport may provide further opportunities to reduce the risk of cerebral ischemia and improve neurodevelopmental outcomes.

Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE): a physiological method of increasing apnoea time in patients with difficult airways.

PubMed

Patel, A; Nouraei, S A R

2015-03-01

Emergency and difficult tracheal intubations are hazardous undertakings where successive laryngoscopy-hypoxaemia-re-oxygenation cycles can escalate to airway loss and the 'can't intubate, can't ventilate' scenario. Between 2013 and 2014, we extended the apnoea times of 25 patients with difficult airways who were undergoing general anaesthesia for hypopharyngeal or laryngotracheal surgery. This was achieved through continuous delivery of transnasal high-flow humidified oxygen, initially to provide pre-oxygenation, and continuing as post-oxygenation during intravenous induction of anaesthesia and neuromuscular blockade until a definitive airway was secured. Apnoea time commenced at administration of neuromuscular blockade and ended with commencement of jet ventilation, positive-pressure ventilation or recommencement of spontaneous ventilation. During this time, upper airway patency was maintained with jaw-thrust. Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) was used in 15 males and 10 females. Mean (SD [range]) age at treatment was 49 (15 [25-81]) years. The median (IQR [range]) Mallampati grade was 3 (2-3 [2-4]) and direct laryngoscopy grade was 3 (3-3 [2-4]). There were 12 obese patients and nine patients were stridulous. The median (IQR [range]) apnoea time was 14 (9-19 [5-65]) min. No patient experienced arterial desaturation < 90%. Mean (SD [range]) post-apnoea end-tidal (and in four patients, arterial) carbon dioxide level was 7.8 (2.4 [4.9-15.3]) kPa. The rate of increase in end-tidal carbon dioxide was 0.15 kPa.min(-1) . We conclude that THRIVE combines the benefits of 'classical' apnoeic oxygenation with continuous positive airway pressure and gaseous exchange through flow-dependent deadspace flushing. It has the potential to transform the practice of anaesthesia by changing the nature of securing a definitive airway in emergency and difficult intubations from a pressured stop-start process to a smooth and unhurried undertaking. © 2014 The Authors Anaesthesia published by John Wiley & Sons Ltd on behalf of Association of Anaesthetists of Great Britain and Ireland.

Implementing a wound care resource nurse program.

PubMed

Tully, Sandra; Ganson, Claudia; Savage, Pamela; Banez, Carol; Zarins, Baiba

2007-08-01

Nurses are leaders in implementing innovations that can create positive outcomes in the prevention and management of pressure ulcers in patients admitted to acute care hospitals. Believing that nurses knowledgeable in best practices could impact prevalence, incidence, and care of pressure ulcers, an educational program was developed in a Canadian healthcare system to inform and empower nurses providing skin and wound care. The program afforded participants the opportunity to acquire the knowledge and skill to recognize patients at risk for developing pressure ulcers and to independently treat Stage I and Stage II pressure ulcers and skin breakdown related to moisture, friction, and shear. The program includes evidence-based practice recommendations and highlights the Best Practice Guidelines developed by the Registered Nurses Association of Ontario, a provincial body taking an active role in the development, implementation, and evaluation of published guidelines derived from global research literature synthesis. Pre- and post participation assessment of 65 nurse participants from three hospitals deemed the program successful in terms of knowledge and fulfillment of their educational expectations. Organizational support to implement the skin and wound care resource nurse role was encouraging and medical directives for Stage I and Stage II pressure ulcers by nurses were implemented. Evaluation and monitoring of program outcomes, including pressure ulcer incidence rates, continue.

Cerebral oxygen saturation and cardiac output during anaesthesia in sitting position for neurosurgical procedures: a prospective observational study.

PubMed

Schramm, P; Tzanova, I; Hagen, F; Berres, M; Closhen, D; Pestel, G; Engelhard, K

2016-10-01

Neurosurgical operations in the dorsal cranium often require the patient to be positioned in a sitting position. This can be associated with decreased cardiac output and cerebral hypoperfusion, and possibly, inadequate cerebral oxygenation. In the present study, cerebral oxygen saturation was measured during neurosurgery in the sitting position and correlated with cardiac output. Perioperative cerebral oxygen saturation was measured continuously with two different monitors, INVOS ® and FORE-SIGHT ® . Cardiac output was measured at eight predefined time points using transoesophageal echocardiography. Forty patients were enrolled, but only 35 (20 female) were eventually operated on in the sitting position. At the first time point, the regional cerebral oxygen saturation measured with INVOS ® was 70 (sd 9)%; thereafter, it increased by 0.0187% min -1 (P<0.01). The cerebral tissue oxygen saturation measured with FORE-SIGHT ® started at 68 (sd 13)% and increased by 0.0142% min -1 (P<0.01). The mean arterial blood pressure did not change. Cardiac output was between 6.3 (sd 1.3) and 7.2 (1.8) litre min -1 at the predefined time points. Cardiac output, but not mean arterial blood pressure, showed a positive and significant correlation with cerebral oxygen saturation. During neurosurgery in the sitting position, the cerebral oxygen saturation slowly increases and, therefore, this position seems to be safe with regard to cerebral oxygen saturation. Cerebral oxygen saturation is stable because of constant CO and MAP, while the influence of CO on cerebral oxygen saturation seems to be more relevant. NCT01275898. © The Author 2016. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Effect of positive end-expiratory pressure on blood loss during retropubic and robot-assisted laparoscopic radical prostatectomy.

PubMed

Ehieli, Eric I; Howard, Lauren E; Monk, Terri G; Ferrandino, Michael N; Polascik, Thomas J; Walther, Philip J; Freedland, Stephen J

2016-08-01

To study the effect of end-expiratory pressure used during anesthesia on blood loss during radical prostatectomy. We evaluated 247 patients who underwent either radical retropubic prostatectomy or robot-assisted laparoscopic prostatectomy at a single institution from 2008 to 2013 by one of four surgeons. Patient characteristics were compared using t-tests, rank sum or χ(2) -tests as appropriate. The association between positive end-expiratory pressure and estimated blood loss was tested using linear regression. Patients were classified into high (≥4 cmH2 O) and low (≤1 cmH2 O) positive-end expiratory pressure groups. Estimated blood loss in radical retropubic prostatectomy was higher in the high positive end-expiratory pressure group (1000 mL vs 800 mL, P = 0.042). Estimated blood loss in robot-assisted laparoscopic prostatectomy was lower in the high positive end-expiratory pressure group (150 mL vs 250 mL, P = 0.015). After adjusting for other factors known to influence blood loss, a 5-cmH2 O increase in positive end-expiratory pressure was associated with a 34.9% increase in estimated blood loss (P = 0.030) for radical retropubic prostatectomy, and a 33.0% decrease for robot-assisted laparoscopic prostatectomy (P = 0.038). In radical retropubic prostatectomy, high positive end-expiratory pressure was associated with higher estimated blood loss, and the benefits of positive end-expiratory pressure should be weighed against the risk of increased estimated blood loss. In robot-assisted laparoscopic prostatectomy, high positive end-expiratory pressure was associated with lower estimated blood loss, and might have more than just pulmonary benefits. © 2016 The Japanese Urological Association.

Upflow bioreactor with septum and pressure release mechanism

DOEpatents

Hansen, Conly L.; Hansen, Carl S.; Pack, Kevin; Milligan, John; Benefiel, Bradley C.; Tolman, C. Wayne; Tolman, Kenneth W.

2010-04-20

An upflow bioreactor includes a vessel having an inlet and an outlet configured for upflow operation. A septum is positioned within the vessel and defines a lower chamber and an upper chamber. The septum includes an aperture that provides fluid communication between the upper chamber and lower chamber. The bioreactor also includes means for releasing pressure buildup in the lower chamber. In one configuration, the septum includes a releasable portion having an open position and a closed position. The releasable portion is configured to move to the open position in response to pressure buildup in the lower chamber. In the open position fluid communication between the lower chamber and the upper chamber is increased. Alternatively the lower chamber can include a pressure release line that is selectively actuated by pressure buildup. The pressure release mechanism can prevent the bioreactor from plugging and/or prevent catastrophic damage to the bioreactor caused by high pressures.

Pressurized tundish for controlling a continuous flow of molten metal

DOEpatents

Lewis, Thomas W.; Hamill, Jr., Paul E.; Ozgu, Mustafa R.; Padfield, Ralph C.; Rego, Donovan N.; Brita, Guido P.

1990-01-01

A pressurized tundish for controlling a continous flow of molten metal characterized by having a pair of principal compartments, one being essentially unpressurized and receiving molten metal introduced thereto, and the other being adapted for maintaining a controlled gaseous pressure over the surface of the fluid metal therein, whereby, by controlling the pressure within the pressurized chamber, metal exiting from the tundish is made to flow continually and at a controlled rate.

Mask pressure effects on the nasal bridge during short-term noninvasive ventilation

PubMed Central

Brill, Anne-Kathrin; Pickersgill, Rachel; Moghal, Mohammad; Morrell, Mary J.; Simonds, Anita K.

2018-01-01

The aim of this study was to assess the influence of different masks, ventilator settings and body positions on the pressure exerted on the nasal bridge by the mask and subjective comfort during noninvasive ventilation (NIV). We measured the pressure over the nasal bridge in 20 healthy participants receiving NIV via four different NIV masks (three oronasal masks, one nasal mask) at three different ventilator settings and in the seated or supine position. Objective pressure measurements were obtained with an I-Scan pressure-mapping system. Subjective comfort of the mask fit was assessed with a visual analogue scale. The masks exerted mean pressures between 47.6±29 mmHg and 91.9±42.4 mmHg on the nasal bridge. In the supine position, the pressure was lower in all masks (57.1±31.9 mmHg supine, 63.9±37.3 mmHg seated; p<0.001). With oronasal masks, a change of inspiratory positive airway pressure (IPAP) did not influence the objective pressure over the nasal bridge. Subjective discomfort was associated with higher IPAP and positively correlated with the pressure on the skin. Objective measurement of pressure on the skin during mask fitting might be helpful for mask selection. Mask fitting in the supine position should be considered in the clinical routine. PMID:29637077

Influence of Air Discontinuity and Wall Effects on the Measurements of Hydraulic Parameters Under Dynamic Conditions

NASA Astrophysics Data System (ADS)

Looms, M. C.; Jensen, K. H.; Wildenschild, D.; Christensen, B. S.; Gudbjerg, J.

2003-12-01

Both dynamic (one-step) and semi-static (syringe pump) outflow experiments were carried out in the lab to test whether the resulting retention characteristics differed according to experiment type. Three sands of varying uniformity and coarseness were packed in a cylindrical sample holder. Compressed air was used to control the air phase pressure, while water was allowed to drain at atmospheric pressure from the outlet at the bottom of the sample. During the outflow experiments the capillary pressure was measured within the sample holder using a tensiometer connected to a pressure transducer. A medical CT-scanner was used to visualize and quantify the outflow patterns within the sand matrix during selected outflow experiments. Positive vertical shifts in capillary pressure during dynamic experiments were found in all three sand types at saturations close to porosity. The size and shape of the shifts corresponded with the dynamic effects found in previous work on the topic. Furthermore, the shifts were slightly greater in the coarsest and most uniform sand type. Numerical simulations of the one-step experiments using HYDRUS1D and T2VOC showed, however, that one of the basic assumptions when calculating the capillary pressure was most likely violated. The air phase could not be considered to be continuous at all times, and assuming this to be the case would result in positive shifts of the retention curves when running T2VOC. The results of using the CT-scanner showed the importance of achieving a homogeneous packing, since the investigated sand packing turned out to have an area at the edge of the sample holder with a higher porosity. This caused the edge to control the initial drainage. Therefore, the data collected at high saturations could not be expected to adequately describe the hydraulic properties of the inner sand. We also found that the time at which the inner sand commenced drainage coincided with a jump in capillary pressure for the resulting measured retention curve.

Sensitization of Upper Airway Mechanoreceptors as a New Pharmacologic Principle to Treat Obstructive Sleep Apnea: Investigations with AVE0118 in Anesthetized Pigs

PubMed Central

Wirth, Klaus J.; Steinmeyer, Klaus; Ruetten, Hartmut

2013-01-01

Study Objectives: Drug treatment for obstructive sleep apnea (OSA) is desirable because at least 30% of patients do not tolerate continuous positive airway pressure (CPAP) treatment. The negative pressure reflex (NPR) involving superficially located mechanoreceptors in the upper airway (UA) is an important mechanism for UA patency inhibitable by topical UA anesthesia (lidocaine). The NPR may serve as a target for pharmacological intervention for a topical treatment of OSA. The objective was to determine the effect of pharmacological augmentation of the NPR on UA collapsibility. Design: We developed a model of UA collapsibility in which application of negative pressures caused UA collapses in spontaneously breathing α-chloralose-urethane anesthetized pigs as indicated by characteristic tracheal pressure and air flow changes. Setting: N/A. Patients or Participants: N/A. Interventions: N/A. Measurements and Results: The potassium channel blocker AVE0118 administered topically to the UA in doses of 1, 3, and 10 mg per nostril sensitized the NPR, shifting the mechanoreceptor response threshold for the genioglossus muscle to more positive pressures (P < 0.001; n = 6 per group) and dose-dependently inhibited UA collapsibility. Ten mg of AVE0118 prevented UA collapses against negative pressures of -150 mbar (P < 0.01) for > 4 h in all pigs, while in control pigs the UA collapsed at -50 mbar or less negative pressures. The effect of AVE0118 was abolished by UA lidocaine anesthesia. Acute intravenous administration of naloxone or acetazolamide was ineffective; paroxetine and mirtazepine were weakly effective and fluoxetine was moderately effective in line with reported clinical efficacy. Conclusion: Topical administration of AVE0118 to the UA is a promising pharmacologic approach for the treatment of OSA. Citation: Wirth KJ; Steinmeyer K; Ruetten H. Sensitization of upper airway mechanoreceptors as a new pharmacologic principle to treat obstructive sleep apnea: investigations with AVE0118 in anesthetized pigs. SLEEP 2013;36(5):699-708. PMID:23633752

Optofluidic lens with tunable focal length and asphericity

PubMed Central

Mishra, Kartikeya; Murade, Chandrashekhar; Carreel, Bruno; Roghair, Ivo; Oh, Jung Min; Manukyan, Gor; van den Ende, Dirk; Mugele, Frieder

2014-01-01

Adaptive micro-lenses enable the design of very compact optical systems with tunable imaging properties. Conventional adaptive micro-lenses suffer from substantial spherical aberration that compromises the optical performance of the system. Here, we introduce a novel concept of liquid micro-lenses with superior imaging performance that allows for simultaneous and independent tuning of both focal length and asphericity. This is achieved by varying both hydrostatic pressures and electric fields to control the shape of the refracting interface between an electrically conductive lens fluid and a non-conductive ambient fluid. Continuous variation from spherical interfaces at zero electric field to hyperbolic ones with variable ellipticity for finite fields gives access to lenses with positive, zero, and negative spherical aberration (while the focal length can be tuned via the hydrostatic pressure). PMID:25224851

Obstructive sleep apnea and insight into mechanisms of sympathetic overactivity.

PubMed

Abboud, François; Kumar, Ravinder

2014-04-01

Nearly two decades ago, we evaluated ten patients with obstructive sleep apnea (OSA). We determined that alarming nocturnal oscillations in arterial pressure and sympathetic nerve activity (SNA) were caused by regulatory coupling and neural interactions among SNA, apnea, and ventilation. Patients with OSA exhibited high levels of SNA when awake, during normal ventilation, and during normoxia, which contributed to hypertension and organ damage. Additionally, we achieved a beneficial and potentially lifesaving reduction in SNA through the application of continuous positive airway pressure (CPAP), which remains a primary therapeutic approach for patients with OSA. With these results in hindsight, we herein discuss three concepts with functional and therapeutic relevance to the integrative neurobiology of autonomic cardiovascular control and to the mechanisms involved in excessive sympathoexcitation in OSA.

The Temporal Dynamics of Two Response-Focused Forms of Emotion Regulation: Experiential, Expressive, and Autonomic Consequences

PubMed Central

Dan-Glauser, Elise S.; Gross, James J.

2011-01-01

This study examines the early affective consequences of two close forms of suppression. Participants (N=37) were shown negative, positive, and neutral pictures and cued either to attend to the pictures, or to perform expressive or physiological suppression (i.e. reduce body reactions). Continuous measures of experience, expressivity, and autonomic responses showed that both suppression strategies produced rapid response modulation. Common effects of the two strategies included a transient increase in negative feeling, a durable decrease in positive feeling, and a decrease in expressivity, cardiovascular activity, and oxygenation. The two strategies were significantly different only in response to positive stimuli, with physiological suppression showing a larger decrease in experience intensity and blood pressure. These results suggest a strong overlap between the two suppression strategies in terms of their early impact on emotional responses. PMID:21361967

Rapid calculation of acoustic fields from arbitrary continuous-wave sources.

PubMed

Treeby, Bradley E; Budisky, Jakub; Wise, Elliott S; Jaros, Jiri; Cox, B T

2018-01-01

A Green's function solution is derived for calculating the acoustic field generated by phased array transducers of arbitrary shape when driven by a single frequency continuous wave excitation with spatially varying amplitude and phase. The solution is based on the Green's function for the homogeneous wave equation expressed in the spatial frequency domain or k-space. The temporal convolution integral is solved analytically, and the remaining integrals are expressed in the form of the spatial Fourier transform. This allows the acoustic pressure for all spatial positions to be calculated in a single step using two fast Fourier transforms. The model is demonstrated through several numerical examples, including single element rectangular and spherically focused bowl transducers, and multi-element linear and hemispherical arrays.

Acute respiratory distress syndrome in combat casualties: military medicine and advances in mechanical ventilation.

PubMed

Morris, Michael James

2006-11-01

Military medicine has made numerous enduring contributions to the advancement of pulmonary medicine. Acute respiratory distress syndrome was first recognized as a complication in battlefield casualties in World War I and continued to play a significant role in the treatment of casualties through the Vietnam War. Innovative surgeons during World War II devised methods to assist their patients with positive pressure breathing. This concept was later adopted and applied to the development of mechanical ventilation in the late 1940s and early 1950s. The continued treatment of acute respiratory distress syndrome in combat casualties by military physicians has provided a major impetus for advances in modern mechanical ventilation and intensive care unit medicine.

Determining soil hydrologic characteristics on a remote forest watershed by continuous monitoring of soil water pressures, rainfall and runoff.

Treesearch

L.R. Ahuja; S. A. El-Swaify

1979-01-01

Continuous monitoring of soil-water pressures, rainfall and runoff under natural conditions was tested as a technique for determining soil hydrologic characteristics of a remote forest watershed plot. A completely battery-powered (and thus portable) pressure transducer–scanner–recorder system was assembled for monitoring of soil-water pressures in...

Continuous 24-hour measurement of middle ear pressure.

PubMed

Tideholm, B; Jönsson, S; Carlborg, B; Welinder, R; Grenner, J

1996-07-01

A new method was developed for continuous measurement of the middle ear pressure during a 24-h period. The equipment consisted of a piezo-electric pressure device and a digital memory. To allow continuous pressure recordings during normal every-day activities the equipment was made light and portable. The measurement accuracy of the equipment as well as the base-line and temperature stability were tested and found to meet to our requirements satisfactorily. In 4 volunteers with different middle ear conditions, a small perforation was made through the tympanic membrane. A rubber stopper containing a small polyethylene tube was fitted into the external ear canal. Tubal function tests were made to establish the equipment's ability to monitor fast pressure changes. The tests were well in accordance with other methods of direct pressure measurements. The equipment was carried by the volunteers for 24 h to monitor any slow or rapid dynamic pressure changes in the middle ear. Four continuous 24-h measurements are presented. The method was found to be suitable for valid measurements of dynamic pressure changes in the middle ear during normal every-day activities. It may become a useful instrument in the search for a better understanding of the development of chronic middle ear disease.

Comparison of Pressure Changes by Head and Neck Position between High-Volume Low-Pressure and Taper-Shaped Cuffs: A Randomized Controlled Trial

PubMed Central

Komasawa, Nobuyasu; Mihara, Ryosuke; Imagawa, Kentaro; Hattori, Kazuo; Minami, Toshiaki

2015-01-01

The present study compared changes in cuff pressure by head and neck position between high-volume low-pressure (HVLP) and taper-shaped (taper) cuffs in a prospective randomized clinical trial. Methods. Forty patients were intubated using tracheal tubes with either HVLP (n = 20; HVLP group) or taper-shaped (n = 20; Taper group) cuffs. Initial cuff pressure was adjusted to 15, 20, or 25 cmH2O in the neutral position. Cuff pressure was evaluated after changing the head and neck positions to flexion, extension, and rotation. Results. Cuff pressure significantly increased with flexion in both HVLP and Taper groups at all initial cuff pressures. It significantly increased with extension in the HVLP group, but not in the Taper group. Cuff pressure did not significantly differ with rotation in either group and was significantly smaller in the Taper group during flexion and extension than in the HVLP group, regardless of initial cuff pressure. Conclusion. Cuff pressure changes with head and neck flexion and extension were smaller in the Taper group than in the HVLP group. Our results highlight the potential for taper cuffs to prevent excessive cuff pressure increases with positional changes in the head and neck. This trial is registered with UMIN000016119. PMID:26509152

Pump out the volume--The effect of tracheal and subelytral pressure pulses on convective gas exchange in a dung beetle, Circellium bacchus (Fabricus).

PubMed

Duncan, Frances D; Förster, Thomas D; Hetz, Stefan K

2010-05-01

Many flightless beetles like the large apterous dung beetle Circellium bacchus, possess a subelytral cavity (SEC) providing an extra air space below the elytra which connects to the tracheal system (TS) via metathoracic and abdominal spiracles. By measuring subelytral and intratracheal pressure as well as body movements and gas exchange simultaneously in a flow-through setup, we investigated the contribution of convection on Circellium respiratory gas exchange. No constriction phase was observed. TS and SEC pressures were always around atmospheric values. During interburst phase open abdominal spiracles and a leaky SEC led to small CO(2)-peaks on a continuous CO(2) baseline, driven by intermittent positive tracheal pressure peaks in anti-phase with small negative subelytral pressure peaks caused by dorso-ventral tergite action. Spiracle opening was accompanied by two types of body movements. Higher frequency telescoping body movements at the beginning of opening resulted in high amplitude SEC and TS pressure peaks. High frequency tergite movements caused subelytral pressure peaks and led to a saw tooth like CO(2) release pattern in a burst. We propose that during the burst open mesothoracic spiracles increase the compliance of the subelytral cavity allowing big volumes of tracheal air being pulled out by convection. Copyright 2009 Elsevier Ltd. All rights reserved.

Regulation of landslide motion by dilatancy and pore pressure feedback

USGS Publications Warehouse

Iverson, R.M.

2005-01-01

A new mathematical model clarifies how diverse styles and rates of landslide motion can result from regulation of Coulomb friction by dilation or contraction of water-saturated basal shear zones. Normalization of the model equations shows that feedback due to coupling between landslide motion, shear zone volume change, and pore pressure change depends on a single dimensionless parameter ??, which, in turn, depends on the dilatancy angle ?? and the intrinsic timescales for pore pressure generation and dissipation. If shear zone soil contracts during slope failure, then ?? 0, and negative feedback permits slow, steady landslide motion to occur while positive pore pressure is supplied by rain infiltration. Steady state slip velocities v0 obey v0 = -(K/??) p*e, where K is the hydraulic conductivity and p*e is the normalized (dimensionless) negative pore pressure generated by dilation. If rain infiltration and attendant pore pressure growth continue unabated, however, their influence ultimately overwhelms the stabilizing influence of negative p*e. Then, unbounded landslide acceleration occurs, accentuated by an instability that develops if ?? diminishes as landslide motion proceeds. Nonetheless, numerical solutions of the model equations show that slow, nearly steady motion of a clay-rich landslide may persist for many months as a result of negative pore pressure feedback that regulates basal Coulomb friction. Similarly stabilized motion is less likely to occur in sand-rich landslides that are characterized by weaker negative feedback.

ACCURACY OF NONINVASIVE ANESTHETIC MONITORING IN THE ANESTHETIZED GIRAFFE (GIRAFFA CAMELOPARDALIS).

PubMed

Bertelsen, Mads F; Grøndahl, Carsten; Stegmann, George F; Sauer, Cathrine; Secher, Niels H; Hasenkam, J Michael; Damkjær, Mads; Aalkjær, Christian; Wang, Tobias

2017-09-01

This study evaluated the accuracy of pulse oximetry, capnography, and oscillometric blood pressure during general anesthesia in giraffes (Giraffa camelopardalis). Thirty-two giraffes anesthetized for physiologic experiments were instrumented with a pulse oximeter transmittance probe positioned on the tongue and a capnograph sampling line placed at the oral end of the endotracheal tube. A human size 10 blood pressure cuff was placed around the base of the tail, and an indwelling arterial catheter in the auricular artery continuously measured blood pressure. Giraffes were intermittently ventilated using a Hudson demand valve throughout the procedures. Arterial blood for blood gas analysis was collected at multiple time points. Relationships between oxygen saturation as determined by pulse oximetry and arterial oxygen saturation, between arterial carbon dioxide partial pressure and end-tidal carbon dioxide, and between oscillometric pressure and invasive arterial blood pressure were assessed, and the accuracy of pulse oximetry, capnography, and oscillometric blood pressure monitoring evaluated using Bland-Altman analysis. All three noninvasive methods provided relatively poor estimates of the reference values. Receiver operating characteristic curve fitting was used to determine cut-off values for hypoxia, hypocapnia, hypercapnia, and hypotension for dichotomous decision-making. Applying these cut-off values, there was reasonable sensitivity for detection of hypocapnia, hypercapnia, and hypotension, but not for hypoxemia. Noninvasive anesthetic monitoring should be interpreted with caution in giraffes and, ideally, invasive monitoring should be employed.

Prevention of Pressure Ulcers Among People With Spinal Cord Injury: A Systematic Review.

PubMed

Groah, Suzanne L; Schladen, Manon; Pineda, Cynthia G; Hsieh, Ching-Hui J

2015-06-01

To evaluate the literature on the effectiveness of bed and wheelchair positioning and repositioning in the prevention of pressure ulcers (PUs) in both the spinal cord injury (SCI) and non-SCI populations. Systematic review. PubMed, CINAHL, PsycINFO, and EMBASE were queried with the subject heading terms "pressure sore," "pressure ulcer," "position or turn in bed, wheelchair," "pressure relief," and "pressure release." All study design types that assessed the effectiveness of bed and wheelchair positioning and pressure relief maneuvers in any patient group and in any setting were sought. Three independent reviewers extracted and summarized details of eligible trials using a standardized method. Two independent reviewers assessed the methodological quality of each trial using the American Academy of Neurology guidelines. When reviewers were not able to reach consensus, a third independent reviewer served as tiebreaker. We identified 2820 publications, of which 49 met inclusion criteria. Of these publications, the subject population was 2834 (923 persons with SCI, 717 persons without SCI, and 1194 healthy control subjects). Among studies examining pressure related to position or repositioning in bed or sitting, procedures for measuring skin pressure and metabolism were highly variable by anatomic location, measurement technique, outcome measure, study site, participant characteristics, and description of position/turning for bed and seated interventions. Numerous factors can influence tissue interface pressures, and no prospective studies had been performed to determine a causal relationship between interface pressure and skin breakdown. Several studies suggest that skin response to pressure differs between subjects with and without SCI. Conflicting results and insufficient evidence for optimal bed and seated positioning and turning and pressure relief maneuvers to prevent PUs in both SCI and non-SCI populations were limiting factors. Although there is no clear optimal positioning or turning frequency in bed, the evidence suggests avoiding the 90° lateral position because of high pressures and PU risk over the trochanters. During sitting, pressures are linearly redistributed from the sitting area during recline and tilt; however, reclining carries with it an increased risk of shear forces on this skin. The evidence does not support conclusive guidelines on positioning or repositioning techniques for PU prevention in bed or during sitting. We conclude that PU risk is highly individualized, with the SCI population at a higher risk, which demands flexible PU prevention strategies for bed/seated positioning and pressure relief maneuvers. Education has and will remain our most powerful ally to thwart this pervasive public health problem. Copyright © 2015. Published by Elsevier Inc.

Physiologic Evaluation of Ventilation Perfusion Mismatch and Respiratory Mechanics at Different Positive End-expiratory Pressure in Patients Undergoing Protective One-lung Ventilation.

PubMed

Spadaro, Savino; Grasso, Salvatore; Karbing, Dan Stieper; Fogagnolo, Alberto; Contoli, Marco; Bollini, Giacomo; Ragazzi, Riccardo; Cinnella, Gilda; Verri, Marco; Cavallesco, Narciso Giorgio; Rees, Stephen Edward; Volta, Carlo Alberto

2018-03-01

Arterial oxygenation is often impaired during one-lung ventilation, due to both pulmonary shunt and atelectasis. The use of low tidal volume (VT) (5 ml/kg predicted body weight) in the context of a lung-protective approach exacerbates atelectasis. This study sought to determine the combined physiologic effects of positive end-expiratory pressure and low VT during one-lung ventilation. Data from 41 patients studied during general anesthesia for thoracic surgery were collected and analyzed. Shunt fraction, high V/Q and respiratory mechanics were measured at positive end-expiratory pressure 0 cm H2O during bilateral lung ventilation and one-lung ventilation and, subsequently, during one-lung ventilation at 5 or 10 cm H2O of positive end-expiratory pressure. Shunt fraction and high V/Q were measured using variation of inspired oxygen fraction and measurement of respiratory gas concentration and arterial blood gas. The level of positive end-expiratory pressure was applied in random order and maintained for 15 min before measurements. During one-lung ventilation, increasing positive end-expiratory pressure from 0 cm H2O to 5 cm H2O and 10 cm H2O resulted in a shunt fraction decrease of 5% (0 to 11) and 11% (5 to 16), respectively (P < 0.001). The PaO2/FIO2 ratio increased significantly only at a positive end-expiratory pressure of 10 cm H2O (P < 0.001). Driving pressure decreased from 16 ± 3 cm H2O at a positive end-expiratory pressure of 0 cm H2O to 12 ± 3 cm H2O at a positive end-expiratory pressure of 10 cm H2O (P < 0.001). The high V/Q ratio did not change. During low VT one-lung ventilation, high positive end-expiratory pressure levels improve pulmonary function without increasing high V/Q and reduce driving pressure.

Effect of adding postoperative noninvasive ventilation to usual care to prevent pulmonary complications in patients undergoing coronary artery bypass grafting: a randomized controlled trial.

PubMed

Al Jaaly, Emad; Fiorentino, Francesca; Reeves, Barnaby C; Ind, Philip W; Angelini, Gianni D; Kemp, Scott; Shiner, Robert J

2013-10-01

We compared the efficacy of noninvasive ventilation with bilevel positive airway pressure added to usual care versus usual care alone in patients undergoing coronary artery bypass grafting. We performed a 2-group, parallel, randomized controlled trial. The primary outcome was time until fit for discharge. Secondary outcomes were partial pressure of carbon dioxide, forced expiratory volume in 1 second, atelectasis, adverse events, duration of intensive care stay, and actual postoperative stay. A total of 129 patients were randomly allocated to bilevel positive airway pressure (66) or usual care (63). Three patients allocated to bilevel positive airway pressure withdrew. The median duration of bilevel positive airway pressure was 16 hours (interquartile range, 11-19). The median duration of hospital stay until fit for discharge was 5 days for the bilevel positive airway pressure group (interquartile range, 4-6) and 6 days for the usual care group (interquartile range, 5-7; hazard ratio, 1.68; 95% confidence interval, 1.08-2.31; P = .019). There was no significant difference in duration of intensive care, actual postoperative stay, and mean percentage of predicted forced expiratory volume in 1 second on day 3. Mean partial pressure of carbon dioxide was significantly reduced 1 hour after bilevel positive airway pressure application, but there was no overall difference between the groups up to 24 hours. Basal atelectasis occurred in 15 patients (24%) in the usual care group and 2 patients (3%) in the bilevel positive airway pressure group. Overall, 30% of patients in the bilevel positive airway pressure group experienced an adverse event compared with 59% in the usual care group. Among patients undergoing elective coronary artery bypass grafting, the use of bilevel positive airway pressure at extubation reduced the recovery time. Supported by trained staff, more than 75% of all patients allocated to bilevel positive airway pressure tolerated it for more than 10 hours. Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Routine use of humidification with nasal continuous positive airway pressure.

PubMed

Worsnop, C J; Miseski, S; Rochford, P D

2010-09-01

Heated humidification can reduce nasal symptoms caused by continuous positive airway pressure (CPAP) treatment, but its routine use has not been studied over the medium term in a randomized controlled trial. The aim of this study is to determine if heated humidification would reduce nasal symptoms and improve adherence with CPAP treatment in all patients with sleep apnoea irrespective of whether they had nasal symptoms initially. A randomized, parallel group design. Patients were treated for 3 months with a Fisher & Paykel HC201 pump with built-in heated humidification, or with the heater disabled and without water. Adherence was measured with a timer built into the pumps. Nasal symptoms were measured with a 10-cm visual analogue scale. There were 25 in the humidification group and 29 in the non-humidification group. After 12 weeks mean (standard deviation) adherence with CPAP was 4.7 (2.4) and 4.5 (2.2) hours per night respectively. Nasal symptoms that were reduced were nose blocked* 6 (12), 18 (26); sneezing* 4 (8), 15 (25); dry nose* 8 (12), 24 (33); stuffy nose* 7 (14), 22(31); dry mouth* 13 (18), 33(36); and runny nose* 6 (17), 14 (29). Parameters marked with an asterisk '*' had P < 0.05 with t-tests. The routine use of heated humidification with CPAP in all patients with sleep apnoea reduced nasal symptoms, but did not improve adherence. © 2010 The Authors. Internal Medicine Journal © 2010 Royal Australasian College of Physicians.

Continuous Positive Airway Pressure in Patients With Obstructive Sleep Apnea and Non-Alcoholic Steatohepatitis: A Systematic Review and Meta-Analysis.

PubMed

Labarca, Gonzalo; Cruz, Rodrigo; Jorquera, Jorge

2018-01-15

Several studies have reported an association between obstructive sleep apnea (OSA) and several extra-pulmonary issues, such as arterial hypertension and insulin resistance. In recent years, the associations between OSA, non-alcoholic fatty liver disease, and non-alcoholic steatohepatitis (NASH) have been published; however, there is a gap between experimental and clinical studies regarding the efficacy of continuous positive airway pressure (CPAP) treatment in patient populations with these conditions. This issue should be considered when deciding on CPAP treatment in patients with OSA, especially in patients with moderate OSA. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) using the following databases: MEDLINE, Lilacs, and CENTRAL. Two independent reviewers performed the search, analysis, data extraction, and critical analysis. From 622 identified studies, we included 5 RCTs that involved patients with OSA and NASH and who were treated with a CPAP device. After CPAP treatment, no changes in liver steatosis, liver fibrosis, and aminotransferase levels (alanine aminotransferase and aspartate aminotransferase) were found. Finally, the quality of evidence using the GRADE approach was low and very low for several outcomes. According to the current analysis, no data regarding the efficacy of CPAP in patients with NASH are available to make recommendations. PROSPERO; ID: CRD42015027981; URL: https://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42015027981. © 2018 American Academy of Sleep Medicine

Efficacy of Bilevel-auto Treatment in Patients with Obstructive Sleep Apnea Not Responsive to or Intolerant of Continuous Positive Airway Pressure Ventilation.

PubMed

Carlucci, Annalisa; Ceriana, Piero; Mancini, Marco; Cirio, Serena; Pierucci, Paola; D'Artavilla Lupo, Nadia; Gadaleta, Felice; Morrone, Elisa; Fanfulla, Francesco

2015-09-15

Ventilation with continuous positive airway pressure (CPAP) is the gold standard therapy for obstructive sleep apnea (OSA). However, it was recently suggested that a novel mode of ventilation, Bilevel-auto, could be equally effective in treating patients unable to tolerate CPAP. The aim of this study was to investigate the ability of Bilevel-auto to treat OSA patients whose nocturnal ventilatory disturbances are not completely corrected by CPAP. We enrolled 66 consecutive OSA patients, not responsive to (group A) or intolerant of (group B) CPAP treatment, after a full night of manual CPAP titration in a laboratory. Full polysomnography data and daytime sleepiness score were compared for each group in the three different conditions: basal, during CPAP, and during Bilevel-auto. The apnea-hypopnea index decreased significantly during CPAP in both groups; however, in the group A, there was a further significant improvement during Bilevel-auto. The same trend was observed for oxygenation indices, while the distribution and the efficiency of sleep did not differ following the switch from CPAP to Bilevel-auto. This study confirmed the role of Bilevel-auto as an effective therapeutic alternative to CPAP in patients intolerant of this latter mode of ventilation. Moreover, extending the use of Bilevel-auto to those OSA patients not responsive to CPAP, we showed a significantly better correction of nocturnal respiratory disturbances. © 2015 American Academy of Sleep Medicine.

Management of continuous positive airway pressure treatment compliance using telemonitoring in obstructive sleep apnoea.

PubMed

Turino, Cecilia; de Batlle, Jordi; Woehrle, Holger; Mayoral, Ana; Castro-Grattoni, Anabel Lourdes; Gómez, Sílvia; Dalmases, Mireia; Sánchez-de-la-Torre, Manuel; Barbé, Ferran

2017-02-01

Continuous positive airway pressure (CPAP) is an effective treatment for obstructive sleep apnoea (OSA), but treatment compliance is often unsatisfactory. This study investigated the efficacy and cost-effectiveness of telemonitoring for improving CPAP compliance.100 newly diagnosed OSA patients requiring CPAP (apnoea-hypopnoea index >15 events·h -1 ) were randomised to standard management or a telemonitoring programme that collected daily information about compliance, air leaks and residual respiratory events, and initiated patient contact to resolve issues. Clinical/anthropometric variables, daytime sleepiness and quality of life were recorded at baseline and after 3 months. Patient satisfaction, additional visits/calls, side-effects and total costs were assessed.There were no significant differences between the standard and telemedicine groups in terms of CPAP compliance (4.9±2.2 versus 5.1±2.1 h·night -1 ), symptoms, clinical variables, quality of life and unwanted effects. Telemedicine was less expensive than standard management (EUR123.65 versus EUR170.97; p=0.022) and was cost-effective (incremental cost-effectiveness ratio EUR17 358.65 per quality-adjusted life-year gained). Overall patient satisfaction was high, but significantly more patients rated satisfaction as high/very high in the standard management versus telemedicine group (96% versus 74%; p=0.034).Telemonitoring did not improve CPAP treatment compliance and was associated with lower patient satisfaction. However, it was more cost-effective than traditional follow-up. Copyright ©ERS 2017.

Treating obstructive sleep apnea in adults with epilepsy

PubMed Central

Malow, B A.; Foldvary-Schaefer, N; Vaughn, B V.; Selwa, L M.; Chervin, R D.; Weatherwax, K J.; Wang, L; Song, Y

2008-01-01

Objective: Small uncontrolled series suggest that treatment of obstructive sleep apnea (OSA) in patients with epilepsy may improve seizure control. Prior to conducting a definitive randomized controlled trial, we addressed critical design issues in a pilot study. Methods: We identified a cohort of adult patients with medically refractory epilepsy and coexisting OSA, documented by polysomnography (PSG). After an 8-week baseline period, subjects with OSA were randomized to therapeutic or sham continuous positive airway pressure (CPAP) for 10 weeks. Subjects maintained seizure calendars and antiepileptic drug dosages were held constant. Results: Sixty-eight subjects with suspected OSA were enrolled and 35 subjects randomized to therapeutic CPAP (22 subjects) or sham (13 subjects) CPAP. Male gender and an elevated sleep apnea questionnaire score were predictive of OSA on PSG. Nineteen subjects in the therapeutic group and all 13 subjects in the sham group completed the trial. Baseline apnea-hypopnea index (AHI) and CPAP adherence were comparable between groups. A significant reduction in AHI was observed in the therapeutic CPAP group as compared to the sham group. Subjects, study coordinators, and principal investigators were unable to predict treatment allocation. Conclusions: This pilot study provided critical information related to study design and feasibility for planning a comprehensive trial to test the hypothesis that treating obstructive sleep apnea in patients with epilepsy improves seizure control. GLOSSARY AEDs = antiepileptic drugs; AHI = apnea-hypopnea index; BMI = body mass index; CPAP = continuous positive airway pressure; OSA = obstructive sleep apnea; PSG = polysomnography. PMID:18711110

Effects of continuous positive airway pressure on neurocognitive architecture and function in patients with obstructive sleep apnoea: study protocol for a multicentre randomised controlled trial

PubMed Central

Xu, Huajun; Wang, Hui; Guan, Jian; Yi, Hongliang; Qian, Yingjun; Zou, Jianyin; Xia, Yunyan; Fu, Yiqun; Li, Xinyi; Jiao, Xiao; Huang, Hengye; Dong, Pin; Yu, Ziwei; Yang, Jun; Xiang, Mingliang; Li, Jiping; Chen, Yanqing; Wang, Peihua; Sun, Yizhou; Li, Yuehua; Zheng, Xiaojian; Jia, Wei; Yin, Shankai

2017-01-01

Objectives Many clinical studies have indicated that obstructive sleep apnoea (OSA), the most common chronic sleep disorder, may affect neurocognitive function, and that treatment for continuous positive airway pressure (CPAP) has some neurocognitive protective effects against the adverse effects of OSA. However, the effects of CPAP treatment on neurocognitive architecture and function remain unclear. Therefore, this multicentre trial was designed to investigate whether and when neurocognitive architecture and function in patients with OSA can be improved by CPAP treatment and to explore the role of gut microbiota in improving neurocognitive function during treatment. Methods/design This study will be a multicentre, randomised, controlled trial with allocation concealment and assessor blinding. A total of 148 eligible patients with moderate to severe OSA will be enrolled from five sleep centres and randomised to receive CPAP with best supportive care (BSC) intervention or BSC intervention alone. Cognitive function, structure and function of brain regions, gut microbiota, metabolites, biochemical variables, electrocardiography, echocardiography, pulmonary function and arterial stiffness will be assessed at baseline before randomisation and at 3, 6 and 12 months. Ethics and dissemination This study has been approved by the Medical Ethics Committee of Shanghai Jiao Tong University Affiliated Sixth People’s Hospital (approval number 2015-79). The results from this study will be published in peer-reviewed journals and at relevant conferences. Trial registration number NCT02886156; pre-results. PMID:28550021

Continuous Positive Airway Pressure: Is it a route for infection in those with Obstructive Sleep Apnoea?

PubMed Central

Mercieca, Liam; Pullicino, Richard; Camilleri, Kyra; Abela, Rodianne; Mangion, Sean Apap; Cassar, Julian; Zammit, Matthew; Gatt, Christine; Deguara, Christopher; Barbara, Christopher; Fsadni, Peter; Montefort, Stephen

2017-01-01

Introduction Continuous positive airway pressure (CPAP) is the standard treatment for obstructive sleep apnoea (OSA), with limited data about the prevalence of respiratory infections and microbial colonization in these patients. Objectives The aim of this study was to determine if CPAP use is associated with respiratory infections and to identify the organisms that colonize or infect these patients. Method A retrospective, case-controlled study in patients diagnosed with OSA was carried out. 137 patients were recruited and interviewed using a questionnaire. A nasal swab was taken from each patient. Patients using CPAP machines had swabs taken from masks and humidifiers. Results 66 (48.2%) patients received CPAP treatment with 60.6% of them having a heated humidifier. 78.8% were male, with the majority using a full face mask (63.6%). No significant difference was seen in the prevalence of rhinosinusitis, lower respiratory tract infections and hospital admissions for pneumonia between CPAP and non-CPAP treated patients. The presence of a humidifier did not influence the prevalence of infections. Commensal flora was predominantly cultured from nasal swabs from both patient groups. Coagulase Negative Staphylococci and Diphtheroids were the main organisms cultured from masks and humidifiers respectively. Conclusions This study shows that the use of CPAP, choice of mask and humidifier have no significant impact on the prevalence of infections and micro-organisms isolated. This is very reassuring to the physician prescribing CPAP therapy and users. PMID:28966735

Sleep Apnea and Circadian Extracellular Fluid Change as Independent Factors for Nocturnal Polyuria.

PubMed

Niimi, Aya; Suzuki, Motofumi; Yamaguchi, Yasuhiro; Ishii, Masaki; Fujimura, Tetsuya; Nakagawa, Tohru; Fukuhara, Hiroshi; Kume, Haruki; Igawa, Yasuhiko; Akishita, Masahiro; Homma, Yukio

2016-10-01

We investigated the relationships among nocturnal polyuria, sleep apnea and body fluid volume to elucidate the pathophysiology of nocturia in sleep apnea syndrome. We enrolled 104 consecutive patients who underwent polysomnography for suspected sleep apnea syndrome. Self-assessed symptom questionnaires were administered to evaluate sleep disorder and lower urinary tract symptoms, including nocturia. Voiding frequency and voided volume were recorded using a 24-hour frequency-volume chart. Body fluid composition was estimated in the morning and at night using bioelectric impedance analysis. Frequency-volume chart data were analyzed in 22 patients after continuous positive airway pressure therapy. Patients with nocturnal polyuria showed a higher apnea-hypopnea index (33.9 vs 24.2, p = 0.03) and a larger circadian change in extracellular fluid adjusted to lean body mass (0.22 vs -0.19, p = 0.019) than those without nocturnal polyuria. These relations were more evident in patients 65 years old or older than in those 64 years or younger. A multivariate linear regression model showed an independent relationship of nocturnal polyuria with the apnea-hypopnea index and the circadian change in extracellular fluid adjusted to lean body mass (p = 0.0012 and 0.022, respectively). Continuous positive airway pressure therapy significantly improved nocturnal polyuria and nocturia only in patients with nocturnal polyuria. This study identified sleep apnea and the circadian change in extracellular fluid as independent factors for nocturnal polyuria. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Obstructive sleep apnoea-hypopnoea and arrhythmias: new updates.

PubMed

Vizzardi, Enrico; Sciatti, Edoardo; Bonadei, Ivano; D'Aloia, Antonio; Curnis, Antonio; Metra, Marco

2017-07-01

Obstructive sleep apnoea-hypopnoea (OSAH) is a prevalent condition characterized by repetitive pharyngeal collapse during sleep, leading to hypoxemia, hypercapnia, and persistent inspiratory efforts against an occluded airway until arousal. Several studies demonstrated that OSAH exerts acute and chronic effects on the cardiovascular system. Thus, although being a respiratory problem, the most important consequences of OSAH are cardiovascular, among which there are arrhythmias. The purpose of this review is to systematically analyse what has been recently published about the relationship between OSAH and every cardiac arrhythmia separately. We searched Pubmed, Scopus, Web of Science and Cochrane Collaboration databases for 'OSAHS arrhythmias', 'OSAH arrhythmias' and 'OSA arrhythmias'. We analyse 1298 articles and meta-analyses, excluding already edited reviews. Arrhythmias, especially of ventricular origin, are frequent in OSAH. Ventricular premature beats, couplets and ventricular tachycardia runs are even more frequent in patients suffering from heart failure. They may be due to left heart remodelling, overwork and ischaemia and can explain at least some sudden deaths occurring between midnight and 6 a.m. Sinus pauses and atrioventricular blocks are increased according to the severity of the disturbance and may be reduced by continuous positive airway pressure therapy, preventing pace-maker implantation. Finally, atrial fibrillation, resistance against antiarrhythmic drugs and recurrences after surgical procedures are strongly related to OSAH. Arrhythmias are frequent in OSAH. Treatment of OSAH may reduce some of them. An implantable cardioverter-defibrillator and continuous positive airway pressure should be considered in some patients.

Impact of effective versus sham continuous positive airway pressure on liver injury in obstructive sleep apnoea: Data from randomized trials.

PubMed

Jullian-Desayes, Ingrid; Tamisier, Renaud; Zarski, Jean-Pierre; Aron-Wisnewsky, Judith; Launois-Rollinat, Sandrine H; Trocme, Candice; Levy, Patrick; Joyeux-Faure, Marie; Pepin, Jean-Louis

2016-02-01

Obstructive sleep apnoea (OSA) could be an independent risk factor for non-alcoholic fatty liver disease (NAFLD) occurrence and progression. The impact of continuous positive airway pressure (CPAP) treatment on non-invasive markers of NAFLD has not been studied. The aim of this study was to evaluate the effect of 6-12 weeks of effective CPAP on the FibroMax test (comprising components including the SteatoTest, NashTest and FibroTest) through three randomized sham controlled studies. The FibroMax test was performed in 103 obstructive sleep apnoea patients (apnoea + hypopnoea index > 15/h) enrolled in a randomized study comparing sham versus effective CPAP. At baseline, 40.4% of patients in the sham CPAP group and 45.5% in the CPAP group exhibited liver steatosis. Furthermore, 39.6% of patients in the sham CPAP group and 58.4% in the CPAP group displayed borderline or possible non-alcoholic steatohepatitis (NASH). Six to twelve weeks of effective CPAP did not demonstrate any impact on reducing steatosis, NASH or liver fibrosis even after adjustment for gender, BMI, baseline apnoea + hypopnoea index and severity of liver injury. A number of non-invasive markers of liver damage are increased in untreated obstructive sleep apnoea patients, potentially contributing to cardiometabolic risk, but they do not improve after 6-12 weeks of effective CPAP treatment. NCT01196845 (ADISAS), NCT00464659 (MneSAS) and NCT00669695 (StatinflaSAS) at ClinicalTrials.gov. © 2015 Asian Pacific Society of Respirology.

Impact of Prophylactic Continuous Positive Airway Pressure on Transient Tachypnea of the Newborn and Neonatal Intensive Care Admission in Newborns Delivered by Elective Cesarean Section.

PubMed

Celebi, Miray Yilmaz; Alan, Serdar; Kahvecioglu, Dilek; Cakir, Ufuk; Yildiz, Duran; Erdeve, Omer; Arsan, Saadet; Atasay, Begum

2016-01-01

This study aims to evaluate the effect of the prophylactic continuous positive airway pressure (CPAP) administration in the delivery room to newborns who were delivered by elective cesarean section (CS). Inborn infants with gestational age between 34(0/7) to 38(6/7) and born by elective CS were prospectively randomized to receive either prophylactic CPAP for 20 minutes via face mask or standardized care without CPAP in the delivery room. Primary outcomes were the incidence of transient tachypnea of the newborn (TTN) and neonatal intensive care unit (NICU) admission due to respiratory distress. A total of 259 infants with a mean gestational age of 37.7 ± 0.8 weeks and birth weight of 3,244 ± 477 g were included. A total of 134 infants received prophylactic CPAP and 125 received control standard care. The rate of NICU admission was significantly lower in prophylactic CPAP group (p = 0.045). Although the rate of TTN was lower in the prophylactic CPAP group, the difference was not statistically significant (p = 0.059). The rate of NICU admission due to respiratory distress was significantly higher in late-preterm cohort than early-term cohort (p < 0.0001). Prophylactic CPAP administration decreases the rate of NICU admission without any side effect in late-preterm and early-term infants delivered by elective CS. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Continuous positive air pressure improves orthonasal olfactory function of patients with obstructive sleep apnea.

PubMed

Walliczek-Dworschak, Ute; Cassel, Werner; Mittendorf, Luisa; Pellegrino, Robert; Koehler, Ulrich; Güldner, Christian; Dworschak, Philipp Otto Georg; Hildebrandt, Olaf; Daniel, Hanna; Günzel, Thomas; Teymoortash, Afshin; Hummel, Thomas

2017-06-01

Recent studies have suggested that patients with obstructive sleep apnea (OSA) might be affected by olfactory impairment. However, more evidence is needed on the effect that OSA has on the chemical senses (olfaction and gustatory) of these patients, and whether continuous positive airway pressure (CPAP) treatment might help to reverse possible impairment. A prospective study was conducted with 44 OSA patients (17 female and 27 male, mean age 54 ± 9.9 years) who were diagnosed via polysomnography and eligible for CPAP treatment. Orthonasal olfactory and gustatory function was measured with the extended Sniffin' Sticks test battery and "taste strips," respectively, before and after CPAP treatment. Baseline olfaction was decreased in OSA patients and after CPAP therapy olfactory scores (odor threshold-discrimination-identification score [TDI]: baseline 29.4 ± 4.11 after CPAP 32.3 ± 4.82; p = 0.001; odor threshold [THR]: baseline 5.28 ± 1.69 after CPAP 6.78 ± 2.61; p = 0.000; odor identification [ID]: baseline 12.9 ± 1.95 after CPAP 13.6 ± 1.33; p = 0.013) improved significantly. In contrast, neither baseline taste function in OSA patients nor gustatory function after treatment seemed to be affected. Orthonasal olfactory function in patients with OSA improves under CPAP therapy; however, gustatory function is not impaired in OSA patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Continuous positive airway pressure with helmet versus mask in infants with bronchiolitis: an RCT.

PubMed

Chidini, Giovanna; Piastra, Marco; Marchesi, Tiziana; De Luca, Daniele; Napolitano, Luisa; Salvo, Ida; Wolfler, Andrea; Pelosi, Paolo; Damasco, Mirco; Conti, Giorgio; Calderini, Edoardo

2015-04-01

Noninvasive continuous positive airway pressure (CPAP) is usually applied with a nasal or facial mask to treat mild acute respiratory failure (ARF) in infants. A pediatric helmet has now been introduced in clinical practice to deliver CPAP. This study compared treatment failure rates during CPAP delivered by helmet or facial mask in infants with respiratory syncytial virus-induced ARF. In this multicenter randomized controlled trial, 30 infants with respiratory syncytial virus-induced ARF were randomized to receive CPAP by helmet (n = 17) or facial mask (n = 13). The primary endpoint was treatment failure rate (defined as due to intolerance or need for intubation). Secondary outcomes were CPAP application time, number of patients requiring sedation, and complications with each interface. Compared with the facial mask, CPAP by helmet had a lower treatment failure rate due to intolerance (3/17 [17%] vs 7/13 [54%], P = .009), and fewer infants required sedation (6/17 [35%] vs 13/13 [100%], P = .023); the intubation rates were similar. In successfully treated patients, CPAP resulted in better gas exchange and breathing pattern with both interfaces. No major complications due to the interfaces occurred, but CPAP by mask had higher rates of cutaneous sores and leaks. These findings confirm that CPAP delivered by helmet is better tolerated than CPAP delivered by facial mask and requires less sedation. In addition, it is safe to use and free from adverse events, even in a prolonged clinical setting. Copyright © 2015 by the American Academy of Pediatrics.

[Cardiac structure and function in patients with obstructive sleep apnea syndrome and co-prevalent arterial hypertension. Influence of CPAP therapy].

PubMed

Duchna, Hans-Werner; Myslinski, Wojciech; Dichmann, Manuel; Rasche, Kurt; Schultze-Werninghaus, Gerhard; Orth, Maritta

2006-01-15

30% of patients with arterial hypertension (AH) are supposed to have a co-prevalent obstructive sleep apnea syndrome (OSAS). Hence, the influence of CPAP (continuous positive airway pressure) therapy on cardiac structure and function was investigated in medically treated patients with AH and co-prevalent OSAS. In all patients AH was treated for at least 5 years. Matched pairs concerning anthropometric data, medical therapy and duration of AH, and severity of OSAS were investigated: 20 patients with untreated OSAS were compared to 20 patients with CPAP therapy for at least 6 months. Further cardiopulmonary diseases were excluded. Cardiac structure and function were assessed echocardiographically. Patients under CPAP therapy had significantly better diastolic left ventricular function, a lower left ventricular mass index, and significantly less frequent signs of left ventricular (eccentric) hypertrophy than patients with untreated OSAS. Furthermore, differences were significant concerning right ventricular wall thickness and mean pulmonary artery pressure. CPAP therapy positively influences left and right cardial structure and function in addition to antihypertensive medication in patients with AH and co-prevalent OSAS.

Impact of continuous positive airway pressure on the pulmonary changes promoted by immersion in water

PubMed Central

Rizzetti, Danize Aparecida; Quadros, Janayna Rodembuch Borba; Ribeiro, Bruna Esmerio; Callegaro, Letícia; Veppo, Aline Arebalo; Wiggers, Giulia Alessandra; Peçanha, Franck Maciel

2017-01-01

ABSTRACT Objective: To determine whether different levels of CPAP improve the lung volumes and capacities of healthy subjects immersed in water. Methods: This was a randomized clinical trial, conducted between April and June of 2016, involving healthy female volunteers who were using oral contraceptives. Three 20-min immersion protocols were applied: control (no CPAP); CPAP5 (CPAP at 5 cmH2O); and CPAP10 (CPAP at 10 cmH2O). We evaluated HR, SpO2, FVC, FEV1, the FEV1/FVC ratio, peak expiratory flow rate (PEFR), and FEF25-75%) at three time points: pre-immersion; 10 min after immersion; and 10 min after the end of each protocol. Results: We evaluated 13 healthy volunteers. The CPAP10 protocol reversed the restrictive pattern of lung function induced by immersion in water, maintaining pulmonary volumes and capacities for a longer period than did the CPAP5 protocol. Conclusions: When the hemodynamic change causing a persistent lung disorder, only the application of higher positive pressures is effective in maintaining long-term improvements in the pulmonary profile. PMID:29340488

Development of acute parotitis after non-invasive ventilation

PubMed Central

Martinez, Eduardo

2017-01-01

A 90-year-old woman underwent laparoscopic exploratory laparotomy for evaluation of suspected mesenteric ischemia. She was promptly extubated postoperatively and transferred to the intensive care unit, where on the first postoperative day she developed hypoxemia necessitating initiation of noninvasive ventilation (NIV) with bilevel positive airway pressure (BiPAP). After 8 hours of BiPAP, she was noted to have swelling, erythema and tenderness in the right preauricular area. Ultrasound evaluation demonstrated an enlarged right parotid gland. With discontinuation of BiPAP and supportive measures, parotitis resolved within 6 days. The mechanism of NIV-induced acute parotitis likely involves transmission of positive pressure to the oral cavity, causing obstruction to salivary flow within the parotid (Stensen) duct. Conditions that increase salivary viscosity and promote salivary stasis, such as advanced age, dehydration, and absence of salivary gland stimulation due to restriction of oral intake, may render patients more susceptible to this complication. As NIV will continue to be a commonly-used modality for the treatment of acute respiratory failure, clinicians should be aware of this phenomenon. PMID:28840025

A study of the effects of innovative and efficient practices on the performance of hospice care organizations.

PubMed

Kirby, Eric G; Keeffe, Michael J; Nicols, Kay M

2007-01-01

Due to changes in social norms, funding initiatives, and other environmental factors, the business of hospice care has significantly evolved over the past 40 years. There has been an influx of for-profit firms, increased consolidation, and significant funding changes. We have witnessed a growth in utilization rates, an increase in insurance coverage, and improved governmental funding. Hospice care organizations have responded to these pressures by pursuing more efficient and innovative business practices. Drawing upon institutional theory, this study seeks to address whether quality of care provided to hospice patients is affected as organizations respond to environmental pressures for innovative and efficient business practices. This study uses hierarchical regression to analyze data from 111 hospices in California. Innovative practices are positively related to quality of care. However, efficient practices have no significant relationship with quality of care. It appears that incorporating innovative practices is positively related to quality of care. Although cost containment may be necessary for continued survival, efficiency improvement efforts do not seem to lead to improved quality of care.

[Burn scars: rehabilitation and skin care].

PubMed

Rochet, Jean-Michel; Zaoui, Affif

2002-12-15

Burn rehabilitation main goal is to minimize the consequences of hypertrophic scars and concomitant contractures. The treatment principles rely on the association of joint posture, continuous pressure completed with range of motion to prevent joint fusion (which happens to adults but not to children). Throughout the different treatment phases and wound evolution, reassessment is necessary to review rehabilitation goals and activities. During the acute phase the alternance of positioning is prioritized in order to keep the affected extremities in antideformity position using splint or other devices. At the rehabilitation phase, treatment is focussed on active/passive range of motion (skin posture) strengthening exercises and use of dynamic splint is introduced to correct contractures. After their discharge home, patients benefit from outpatient rehab until scar maturation (approximately 18 months). The treatment consists mainly on active/passive range of motion, scar massage, strengthening exercise and endurance retraining. Also modalities (such as thermal bath and high pressure water spray) are used to address itching problems and for scar softening. Finally, reconstructive surgery can be performed to correct excessive scarring or joint contracture for better functional or cosmetic outcome.

[Comorbidities of heart failure: sleep apnea].

PubMed

Woehrle, H; Oldenburg, O; Stadler, S; Arzt, M

2018-05-01

Since sleep apnea often occurs in heart failure, physicians regularly need to decide whether further diagnostic procedures and/or treatment are required. Which types of sleep apnea occur in heart failure patients? When is treatment needed? Which treatments and treatment goals are appropriate? Clinical trials and guidelines as well as their implementation in clinical practice are discussed. At least 40% of patients with heart failure, both with reduced and preserved left ventricular ejection fraction (HFrEF and HFpEF, respectively), suffer from relevant sleep apnea. In heart failure patients both obstructive and central sleep apnea are associated with increased mortality. In HFrEF as well as in HFpEF patients with obstructive sleep apnea, treatment with continuous positive airway pressure (CPAP) achieves symptomatic and functional improvements. In patients with HFpEF, positive airway pressure treatment of central sleep apnea may be beneficial. In patients with HFrEF and left ventricular ejection fraction ≤45%, adaptive servoventilation is contraindicated. Sleep apnea is highly prevalent in heart failure patients and its treatment in specific patient groups can improve symptoms and functional outcomes. Thus, testing for sleep apnea is recommended.

Space Launch System Booster Separation Aerodynamic Testing in the NASA Langley Unitary Plan Wind Tunnel

NASA Technical Reports Server (NTRS)

Wilcox, Floyd J., Jr.; Pinier, Jeremy T.; Chan, David T.; Crosby, William A.

2016-01-01

A wind-tunnel investigation of a 0.009 scale model of the Space Launch System (SLS) was conducted in the NASA Langley Unitary Plan Wind Tunnel to characterize the aerodynamics of the core and solid rocket boosters (SRBs) during booster separation. High-pressure air was used to simulate plumes from the booster separation motors (BSMs) located on the nose and aft skirt of the SRBs. Force and moment data were acquired on the core and SRBs. These data were used to corroborate computational fluid dynamics (CFD) calculations that were used in developing a booster separation database. The SRBs could be remotely positioned in the x-, y-, and z-direction relative to the core. Data were acquired continuously while the SRBs were moved in the axial direction. The primary parameters varied during the test were: core pitch angle; SRB pitch and yaw angles; SRB nose x-, y-, and z-position relative to the core; and BSM plenum pressure. The test was conducted at a free-stream Mach number of 4.25 and a unit Reynolds number of 1.5 million per foot.

Composite Behavior of Insulated Concrete Sandwich Wall Panels Subjected to Wind Pressure and Suction

PubMed Central

Choi, Insub; Kim, JunHee; Kim, Ho-Ryong

2015-01-01

A full-scale experimental test was conducted to analyze the composite behavior of insulated concrete sandwich wall panels (ICSWPs) subjected to wind pressure and suction. The experimental program was composed of three groups of ICSWP specimens, each with a different type of insulation and number of glass-fiber-reinforced polymer (GFRP) shear grids. The degree of composite action of each specimen was analyzed according to the load direction, type of the insulation, and number of GFRP shear grids by comparing the theoretical and experimental values. The failure modes of the ICSWPs were compared to investigate the effect of bonds according to the load direction and type of insulation. Bonds based on insulation absorptiveness were effective to result in the composite behavior of ICSWP under positive loading tests only, while bonds based on insulation surface roughness were effective under both positive and negative loading tests. Therefore, the composite behavior based on surface roughness can be applied to the calculation of the design strength of ICSWPs with continuous GFRP shear connectors. PMID:28788001

Impact of continuous positive airway pressure on the pulmonary changes promoted by immersion in water.

PubMed

Rizzetti, Danize Aparecida; Quadros, Janayna Rodembuch Borba; Ribeiro, Bruna Esmerio; Callegaro, Letícia; Veppo, Aline Arebalo; Wiggers, Giulia Alessandra; Peçanha, Franck Maciel

2017-01-01

To determine whether different levels of CPAP improve the lung volumes and capacities of healthy subjects immersed in water. This was a randomized clinical trial, conducted between April and June of 2016, involving healthy female volunteers who were using oral contraceptives. Three 20-min immersion protocols were applied: control (no CPAP); CPAP5 (CPAP at 5 cmH2O); and CPAP10 (CPAP at 10 cmH2O). We evaluated HR, SpO2, FVC, FEV1, the FEV1/FVC ratio, peak expiratory flow rate (PEFR), and FEF25-75%) at three time points: pre-immersion; 10 min after immersion; and 10 min after the end of each protocol. We evaluated 13 healthy volunteers. The CPAP10 protocol reversed the restrictive pattern of lung function induced by immersion in water, maintaining pulmonary volumes and capacities for a longer period than did the CPAP5 protocol. When the hemodynamic change causing a persistent lung disorder, only the application of higher positive pressures is effective in maintaining long-term improvements in the pulmonary profile.

Age-Related Variability in Tongue Pressure Patterns for Maximum Isometric and Saliva Swallowing Tasks

PubMed Central

Peladeau-Pigeon, Melanie

2017-01-01

Purpose The ability to generate tongue pressure plays a major role in bolus transport in swallowing. In studies of motor control, stability or variability of movement is a feature that changes with age, disease, task complexity, and perturbation. In this study, we explored whether age and tongue strength influence the stability of the tongue pressure generation pattern during isometric and swallowing tasks in healthy volunteers. Method Tongue pressure data, collected using the Iowa Oral Performance Instrument, were analyzed from 84 participants in sex-balanced and decade age-group strata. Tasks included maximum anterior and posterior isometric pressures and regular-effort saliva swallows. The cyclic spatiotemporal index (cSTI) was used to capture stability (vs. variability) in patterns of pressure generation. Mixed-model repeated measures analyses of covariance were performed separately for each task (anterior and posterior isometric pressures, saliva swallows) with between-participant factors of age group and sex, a within-participant factor of task repetition, and a continuous covariate of tongue strength. Results Neither age group nor sex effects were found. There was no significant relationship between tongue strength and the cSTI on the anterior isometric tongue pressure task (r = −.11). For the posterior isometric tongue pressure task, a significant negative correlation (r = −.395) was found between tongue strength and the cSTI. The opposite pattern of a significant positive correlation (r = .29) between tongue strength and the cSTI was seen for the saliva swallow task. Conclusions Tongue pressure generation patterns appear highly stable across repeated maximum isometric and saliva swallow tasks, despite advancing age. Greater pattern variability is seen with weaker posterior isometric pressures. Overall, saliva swallows had the lowest pressure amplitudes and highest pressure pattern variability as measured by the cSTI. PMID:29114767

49 CFR 179.101 - Individual specification requirements applicable to pressure tank car tanks.

Code of Federal Regulations, 2014 CFR

2014-10-01

... to pressure tank car tanks. 179.101 Section 179.101 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109...

Force and moment rotordynamic coefficients for pump-impeller shroud surfaces

NASA Technical Reports Server (NTRS)

Childs, Dara W.

1987-01-01

Governing equations of motion are derived for a bulk-flow model of the leakage path between an impeller shroud and a pump housing. The governing equations consist of a path-momentum, a circumferential - momentum, and a continuity equation. The fluid annulus between the impeller shroud and pump housing is assumed to be circumferentially symmetric when the impeller is centered; i.e., the clearance can vary along the pump axis but does not vary in the circumferential direction. A perturbation expansion of the governing equations in the eccentricity ratio yields a set of zeroth and first-order governing equations. The zeroth-order equations define the leaking rate and the circumferential and path velocity distributions and pressure distributions for a centered impeller position. The first-order equations define the perturbations in the velocity and pressure distributions due to either a radial-displacement perturbation or a tilt perturbation of the impeller. Integration of the perturbed pressure and shear-stress distribution acting on the rotor yields the reaction forces and moments acting on the impeller face.

[Canopy conductance characteristics of poplar in agroforestry system in west Liaoning Province of Northeast China].

PubMed

Li, Zheng; Niu, Li-Hua; Yuan, Feng-Hui; Guan, De-Xin; Wang, An-Zhi; Jin, Chang-Jie; Wu, Jia-Bing

2012-11-01

By using Granier' s thermal dissipation probe, the sap flow of poplar in a poplar-maize agroforestry system in west Liaoning was continuously measured, and as well, the environmental factors such as air temperature, air humidity, net radiation, wind speed, soil temperature, and soil moisture content were synchronically measured. Based on the sap flow data, the canopy conductance of poplar was calculated with simplified Penman-Monteith equation. In the study area, the diurnal variation of poplar' s canopy conductance showed a "single peak" curve, whereas the seasonal variation showed a decreasing trend. There was a negative logarithm relationship between the canopy conductance and vapor pressure deficit, with the sensitivity of canopy conductance to vapor pressure deficit change decreased gradually from May to September. The canopy conductance had a positive relationship with solar radiation. In different months, the correlation degree of canopy conductance with environmental factors differed. The vapor pressure deficit in the whole growth period of poplar was the most significant environmental factor correlated with the canopy conductance.

Assessment of upper airway mechanics during sleep.

PubMed

Farré, Ramon; Montserrat, Josep M; Navajas, Daniel

2008-11-30

Obstructive sleep apnea, which is the most prevalent sleep breathing disorder, is characterized by recurrent episodes of upper airway collapse and reopening. However, the mechanical properties of the upper airway are not directly measured in routine polysomnography because only qualitative sensors (thermistors for flow and thoraco-abdominal bands for pressure) are used. This review focuses on two techniques that quantify upper airway obstruction during sleep. A Starling model of collapsible conduit allows us to interpret the mechanics of the upper airway by means of two parameters: the critical pressure (Pcrit) and the upstream resistance (Rup). A simple technique to measure Pcrit and Rup involves the application of different levels of continuous positive airway pressure (CPAP) during sleep. The forced oscillation technique is another non-invasive procedure for quantifying upper airway impedance during the breathing cycle in sleep studies. The latest developments in these two methods allow them to be easily applied on a routine basis in order to more fully characterize upper airway mechanics in patients with sleep breathing disorders.

Idiopathic normal pressure hydrocephalus: the CSF tap-test may predict the clinical response to shunting.

PubMed

Sand, T; Bovim, G; Grimse, R; Myhr, G; Helde, G; Cappelen, J

1994-05-01

A follow-up study was performed in nine patients with idiopathic normal pressure hydrocephalus (NPH) 37 months (mean) after shunting and 10 non-operated controls with comparable degrees of ventricular enlargement, gait disorder, and dementia. Five operated patients vs. no controls reported sustained general improvement (p < 0.02). Objectively improved gait at follow-up (compared with preoperative status) was found in five of the six tested NPH-patients vs. none of the controls (p < 0.005). Improved gait and/or psychometric function was found in four of six NPH vs. none of eight control patients (p < 0.02) after drainage of 40 ml cerebrospinal fluid (CSF tap-test). Improved gait during the CSF tap-test predicted continued improvement at follow-up. Temporal horn size was the only radiological variable which showed a (moderate) positive correlation with resistance to CSF absorption and rate of pressure increase. The size of the third ventricle diminished in parallel with clinical improvement.

Seafloor horizontal positioning from a continuously operating buoy-based GPS-acoustic array

NASA Astrophysics Data System (ADS)

Chadwell, C. D.; Brown, K. M.; Tryon, M. D.; Send, U.

2009-12-01

Seafloor horizontal positions in a global frame were estimated daily from an autonomous buoy operating continuously over several months. The buoy (GEOCE) was moored offshore San Diego in 100-m-deep waters above an array of 4 seafloor transponders. Dual-frequency GPS data were collected at 1-Hz at a main antenna on the buoy and at 3 shore stations to provide continuous 2-3 cm positions of the buoy main antenna. Two single-frequency antennas on the buoy along with the main antenna were used to estimate the buoy attitude and short-term velocity. At one minute intervals the two-way acoustic travel time was measured between the buoy and transponders. During this few second span when transmitting and receiving acoustic signals, 10-Hz attitude and velocity were collected to locate the position of the transducer mounted approximately 2 m below the water line. The GPS and acoustic data were recorded internally and transmitted to shore over a cell-phone link and/or a wireless Ethernet. GPS data were combined with the acoustic data to estimate the array location at 1 minute intervals. The 1-minute positions are combined to provide a daily estimate of the array position. The buoy is autonomous, solar-powered and in addition to the GPS and acoustic data collects air pressure, temperature, wind speed/direction as well as water level at the surface and conductivity and temperature along the mooring line from near the sea surface to just above the sea floor. Here we report results from the horizontal positioning effort from Phase I of the project in shallow waters. The project also includes a vertical deformation sensor and physical oceanographic monitoring. A deep water (nominally 1000 m) test is planned for 2010. This work is supported by NSF-OCE-0551363 of the Ocean Technology and Interdisciplinary Coordination Program.

Development of a real-time monitoring system for intra-fractional motion in intracranial treatment using pressure sensors.

PubMed

Inata, Hiroki; Araki, Fujio; Kuribayashi, Yuta; Hamamoto, Yasushi; Nakayama, Shigeki; Sodeoka, Noritaka; Kiriyama, Tetsukazu; Nishizaki, Osamu

2015-09-21

This study developed a dedicated real-time monitoring system to detect intra-fractional head motion in intracranial radiotherapy using pressure sensors. The dedicated real-time monitoring system consists of pressure sensors with a thickness of 0.6 mm and a radius of 9.1 mm, a thermoplastic mask, a vacuum pillow, and a baseplate. The four sensors were positioned at superior-inferior and right-left sides under the occipital area. The sampling rate of pressure sensors was set to 5 Hz. First, we confirmed that the relationship between the force and the displacement of the vacuum pillow follows Hook's law. Next, the spring constant for the vacuum pillow was determined from the relationship between the force given to the vacuum pillow and the displacement of the head, detected by Cyberknife target locating system (TLS) acquisitions in clinical application. Finally, the accuracy of our system was evaluated by using the 2  ×  2 confusion matrix. The regression lines between the force, y, and the displacement, x, of the vacuum pillow were given by y = 3.8x, y = 4.4x, and y = 5.0x when the degree of inner pressure was  -12 kPa,-20 kPa, and  -27 kPa, respectively. The spring constant of the vacuum pillow was 1.6 N mm(-1) from the 6D positioning data of a total of 2999 TLS acquisitions in 19 patients. Head motions of 1 mm, 1.5 mm, and 2 mm were detected in real-time with the accuracies of 67%, 84%, and 89%, respectively. Our system can detect displacement of the head continuously during every interval of TLS with a resolution of 1-2 mm without any radiation exposure.

Estimation of Pharyngeal Collapsibility During Sleep by Peak Inspiratory Airflow.

PubMed

Azarbarzin, Ali; Sands, Scott A; Taranto-Montemurro, Luigi; Oliveira Marques, Melania D; Genta, Pedro R; Edwards, Bradley A; Butler, James; White, David P; Wellman, Andrew

2017-01-01

Pharyngeal critical closing pressure (Pcrit) or collapsibility is a major determinant of obstructive sleep apnea (OSA) and may be used to predict the success/failure of non-continuous positive airway pressure (CPAP) therapies. Since its assessment involves overnight manipulation of CPAP, we sought to validate the peak inspiratory flow during natural sleep (without CPAP) as a simple surrogate measurement of collapsibility. Fourteen patients with OSA attended overnight polysomnography with pneumotachograph airflow. The middle third of the night (non-rapid eye movement sleep [NREM]) was dedicated to assessing Pcrit in passive and active states via abrupt and gradual CPAP pressure drops, respectively. Pcrit is the extrapolated CPAP pressure at which flow is zero. Peak and mid-inspiratory flow off CPAP was obtained from all breaths during sleep (excluding arousal) and compared with Pcrit. Active Pcrit, measured during NREM sleep, was strongly correlated with both peak and mid-inspiratory flow during NREM sleep (r = -0.71, p < .005 and r = -0.64, p < .05, respectively), indicating that active pharyngeal collapsibility can be reliably estimated from simple airflow measurements during polysomnography. However, there was no significant relationship between passive Pcrit, measured during NREM sleep, and peak or mid-inspiratory flow obtained from NREM sleep. Flow measurements during REM sleep were not significantly associated with active or passive Pcrit. Our study demonstrates the feasibility of estimating active Pcrit using flow measurements in patients with OSA. This method may enable clinicians to estimate pharyngeal collapsibility without sophisticated equipment and potentially aid in the selection of patients for non- positive airway pressure therapies. © Sleep Research Society 2016. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

Visit-to-visit and 24-h blood pressure variability: association with endothelial and smooth muscle function in African Americans.

PubMed

Diaz, K M; Veerabhadrappa, P; Kashem, M A; Thakkar, S R; Feairheller, D L; Sturgeon, K M; Ling, C; Williamson, S T; Kretzschmar, J; Lee, H; Grimm, H; Babbitt, D M; Vin, C; Fan, X; Crabbe, D L; Brown, M D

2013-11-01

The purpose of this study was to investigate the association of visit-to-visit and 24-h blood pressure (BP) variability with markers of endothelial injury and vascular function. We recruited 72 African Americans who were non-diabetic, non-smoking and free of cardiovascular (CV) and renal disease. Office BP was measured at three visits and 24-h ambulatory BP monitoring was conducted to measure visit-to-visit and 24-h BP variability, respectively. The 5-min time-course of brachial artery flow-mediated dilation and nitroglycerin-mediated dilation were assessed as measures of endothelial and smooth muscle function. Fasted blood samples were analyzed for circulating endothelial microparticles (EMPs). Significantly lower CD31+CD42- EMPs were found in participants with high visit-to-visit systolic blood pressure (SBP) variability or high 24-h diastolic blood pressure (DBP) variability. Participants with high visit-to-visit DBP variability had significantly lower flow-mediated dilation and higher nitroglycerin-mediated dilation at multiple time-points. When analyzed as continuous variables, 24-h mean arterial pressure variability was inversely associated with CD62+ EMPs; visit-to-visit DBP variability was inversely associated with flow-mediated dilation normalized by smooth muscle function and was positively associated with nitroglycerin-mediated dilation; and 24-h DBP variability was positively associated with nitroglycerin-mediated dilation. All associations were independent of age, gender, body mass index and mean BP. In conclusion, in this cohort of African Americans visit-to-visit and 24-h BP variability were associated with measures of endothelial injury, endothelial function and smooth muscle function. These results suggest that BP variability may influence the pathogenesis of CV disease, in part, through influences on vascular health.