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Sample records for airway opening pressure

  1. Deviation of tracheal pressure from airway opening pressure during high-frequency oscillatory ventilation in a porcine lung model.

    PubMed

    Johannes, Amélie; Zollhoefer, Bernd; Eujen, Ulrike; Kredel, Markus; Rauch, Stefan; Roewer, Norbert; Muellenbach, Ralf M

    2013-04-01

    Oxygenation during high-frequency oscillatory ventilation is secured by a high level of mean airway pressure. Our objective was to identify a pressure difference between the airway opening of the respiratory circuit and the trachea during application of different oscillatory frequencies. Six female Pietrain pigs (57.1 ± 3.6 kg) were first ventilated in a conventional mechanical ventilation mode. Subsequently, the animals were switched to high-frequency oscillatory ventilation by setting mean airway opening pressure 5 cmH(2)O above the one measured during controlled mechanical ventilation. Measurements at the airway opening and at tracheal levels were performed in healthy lungs and after induction of acute lung injury by surfactant depletion. During high-frequency oscillatory ventilation, the airway opening pressure was set at a constant level. The pressure amplitude was fixed at 90 cmH(2)O. Starting from an oscillatory frequency of 3 Hz, the frequency was increased in steps of 3 Hz to 15 Hz and then decreased accordingly. At each frequency, measurements were performed in the trachea through a side-lumen of the endotracheal tube and the airway opening pressure was recorded. The pressure difference was calculated. At every oscillatory frequency, a pressure loss towards the trachea could be shown. This pressure difference increased with higher oscillatory frequencies (3 Hz 2.2 ± 2.1 cmH(2)O vs. 15 Hz 7.5 ± 1.8 cmH(2)O). The results for healthy and injured lungs were similar. Tracheal pressures decreased with higher oscillatory frequencies. This may lead to pulmonary derecruitment. This has to be taken into consideration when increasing oscillatory frequencies and differentiated pressure settings are mandatory.

  2. 21 CFR 868.2600 - Airway pressure monitor.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Airway pressure monitor. 868.2600 Section 868.2600...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2600 Airway pressure monitor. (a) Identification. An airway pressure monitor is a device used to measure the pressure in a patient's upper...

  3. 21 CFR 868.2600 - Airway pressure monitor.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Airway pressure monitor. 868.2600 Section 868.2600...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2600 Airway pressure monitor. (a) Identification. An airway pressure monitor is a device used to measure the pressure in a patient's upper...

  4. 21 CFR 868.2600 - Airway pressure monitor.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Airway pressure monitor. 868.2600 Section 868.2600...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2600 Airway pressure monitor. (a) Identification. An airway pressure monitor is a device used to measure the pressure in a patient's upper...

  5. 21 CFR 868.2600 - Airway pressure monitor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Airway pressure monitor. 868.2600 Section 868.2600...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2600 Airway pressure monitor. (a) Identification. An airway pressure monitor is a device used to measure the pressure in a patient's upper...

  6. 21 CFR 868.2600 - Airway pressure monitor.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Airway pressure monitor. 868.2600 Section 868.2600...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2600 Airway pressure monitor. (a) Identification. An airway pressure monitor is a device used to measure the pressure in a patient's upper...

  7. Detection of Upper Airway Status and Respiratory Events by a Current Generation Positive Airway Pressure Device

    PubMed Central

    Li, Qing Yun; Berry, Richard B.; Goetting, Mark G.; Staley, Bethany; Soto-Calderon, Haideliza; Tsai, Sheila C.; Jasko, Jeffrey G.; Pack, Allan I.; Kuna, Samuel T.

    2015-01-01

    Study Objectives: To compare a positive airway pressure (PAP) device's detection of respiratory events and airway status during device-detected apneas with events scored on simultaneous polysomnography (PSG). Design: Prospective PSGs of patients with sleep apnea using a new-generation PAP device. Settings: Four clinical and academic sleep centers. Patients: Forty-five patients with obstructive sleep apnea (OSA) and complex sleep apnea (Comp SA) performed a PSG on PAP levels adjusted to induce respiratory events. Interventions: None. Measurements and Results: PAP device data identifying the type of respiratory event and whether the airway during a device-detected apnea was open or obstructed were compared to time-synced, manually scored respiratory events on simultaneous PSG recording. Intraclass correlation coefficients between device-detected and PSG scored events were 0.854 for apnea-hypopnea index (AHI), 0.783 for apnea index, 0.252 for hypopnea index, and 0.098 for respiratory event-related arousals index. At a device AHI (AHIFlow) of 10 events/h, area under the receiver operating characteristic curve was 0.98, with sensitivity 0.92 and specificity 0.84. AHIFlow tended to overestimate AHI on PSG at values less than 10 events/h. The device detected that the airway was obstructed in 87.4% of manually scored obstructive apneas. Of the device-detected apneas with clear airway, a minority (15.8%) were manually scored as obstructive apneas. Conclusions: A device-detected apnea-hypopnea index (AHIFlow) < 10 events/h on a positive airway pressure device is strong evidence of good treatment efficacy. Device-detected airway status agrees closely with the presumed airway status during polysomnography scored events, but should not be equated with a specific type of respiratory event. Citation: Li QY, Berry RB, Goetting MG, Staley B, Soto-Calderon H, Tsai SC, Jasko JG, Pack AI, Kuna ST. Detection of upper airway status and respiratory events by a current generation positive

  8. 21 CFR 868.1780 - Inspiratory airway pressure meter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Inspiratory airway pressure meter. 868.1780... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1780 Inspiratory airway pressure meter. (a) Identification. An inspiratory airway pressure meter is a device used to measure the...

  9. 21 CFR 868.1780 - Inspiratory airway pressure meter.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Inspiratory airway pressure meter. 868.1780... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1780 Inspiratory airway pressure meter. (a) Identification. An inspiratory airway pressure meter is a device used to measure the...

  10. 21 CFR 868.1780 - Inspiratory airway pressure meter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Inspiratory airway pressure meter. 868.1780... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1780 Inspiratory airway pressure meter. (a) Identification. An inspiratory airway pressure meter is a device used to measure the...

  11. 21 CFR 868.1780 - Inspiratory airway pressure meter.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Inspiratory airway pressure meter. 868.1780... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1780 Inspiratory airway pressure meter. (a) Identification. An inspiratory airway pressure meter is a device used to measure the...

  12. 21 CFR 868.1780 - Inspiratory airway pressure meter.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Inspiratory airway pressure meter. 868.1780... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1780 Inspiratory airway pressure meter. (a) Identification. An inspiratory airway pressure meter is a device used to measure the...

  13. CPAP (Continuous Positive Airway Pressure)

    MedlinePlus

    ... Clinical Trials High Blood Pressure National Center on Sleep Disorders Research Oxygen Therapy Respiratory Distress Syndrome Sleep Apnea ... This Content: Updated: December 9, 2016 Sleep Infographic Sleep Disorders & Insufficient Sleep: Improving Health through Research National Institutes ...

  14. Mouth-opening increases upper-airway collapsibility without changing resistance during midazolam sedation.

    PubMed

    Ayuse, T; Inazawa, T; Kurata, S; Okayasu, I; Sakamoto, E; Oi, K; Schneider, H; Schwartz, A R

    2004-09-01

    Sedative doses of anesthetic agents affect upper-airway function. Oral-maxillofacial surgery is frequently performed on sedated patients whose mouths must be as open as possible if the procedures are to be accomplished successfully. We examined upper-airway pressure-flow relationships in closed mouths, mouths opened moderately, and mouths opened maximally to test the hypothesis that mouth-opening compromises upper-airway patency during midazolam sedation. From these relationships, upper-airway critical pressure (Pcrit) and upstream resistance (Rua) were derived. Maximal mouth-opening increased Pcrit to -3.6 +/- 2.9 cm H2O compared with -8.7 +/- 2.8 (p = 0.002) for closed mouths and -7.2 +/- 4.1 (p = 0.038) for mouths opened moderately. In contrast, Rua was similar in all three conditions (18.4 +/- 6.6 vs. 17.7 +/- 7.6 vs. 21.5 +/- 11.6 cm H2O/L/sec). Moreover, maximum mouth-opening produced an inspiratory airflow limitation at atmosphere that was eliminated when nasal pressure was adjusted to 4.3 +/- 2.7 cm H2O. We conclude that maximal mouth-opening increases upper-airway collapsibility, which contributes to upper-airway obstruction at atmosphere during midazolam sedation.

  15. When continuous positive airway pressure (CPAP) fails

    PubMed Central

    Virk, Jagdeep S.

    2016-01-01

    Obstructive sleep apnoea (OSA) is increasingly prevalent, particularly in the context of the obesity epidemic, and is associated with a significant social, health and economic impact. The gold standard of treatment for moderate to severe OSA is continuous positive airway pressure (CPAP). However compliance rates can be low. Methodology to improve patient tolerance to CPAP alongside with alternative, non-surgical and surgical, management strategies are discussed. All patients that fail CPAP therapy would benefit from formal upper airway evaluation by the otolaryngologist to identify any obvious causes and consider site-specific surgical therapies. Patient selection is integral to ensuring successful outcomes. A multidisciplinary team is needed to manage these patients. PMID:27867577

  16. Airway pressure with chest compressions versus Heimlich manoeuvre in recently dead adults with complete airway obstruction.

    PubMed

    Langhelle, A; Sunde, K; Wik, L; Steen, P A

    2000-04-01

    In a previous case report a standard chest compression successfully removed a foreign body from the airway after the Heimlich manoeuvre had failed. Based on this case, standard chest compressions and Heimlich manoeuvres were performed by emergency physicians on 12 unselected cadavers with a simulated complete airway obstruction in a randomised crossover design. The mean peak airway pressure was significantly lower with abdominal thrusts compared to chest compressions, 26.4+/-19.8 cmH(2)O versus 40.8+/-16.4 cmH(2)O, respectively (P=0.005, 95% confidence interval for the mean difference 5.3-23.4 cmH(2)O). Standard chest compressions therefore have the potential of being more effective than the Heimlich manoeuvre for the management of complete airway obstruction by a foreign body in an unconscious patient. Removal of the Heimlich manoeuvre from the resuscitation algorithm for unconscious patients with suspected airway obstruction will also simplify training.

  17. Clinical review: Biphasic positive airway pressure and airway pressure release ventilation

    PubMed Central

    Putensen, Christian; Wrigge, Hermann

    2004-01-01

    This review focuses on mechanical ventilation strategies that allow unsupported spontaneous breathing activity in any phase of the ventilatory cycle. By allowing patients with the acute respiratory distress syndrome to breathe spontaneously, one can expect improvements in gas exchange and systemic blood flow, based on findings from both experimental and clinical trials. In addition, by increasing end-expiratory lung volume, as occurs when using biphasic positive airway pressure or airway pressure release ventilation, recruitment of collapsed or consolidated lung is likely to occur, especially in juxtadiaphragmatic lung legions. Traditional approaches to mechanical ventilatory support of patients with acute respiratory distress syndrome require adaptation of the patient to the mechanical ventilator using heavy sedation and even muscle relaxation. Recent investigations have questioned the utility of sedation, muscle paralysis and mechanical control of ventilation. Furthermore, evidence exists that lowering sedation levels will decrease the duration of mechanical ventilatory support, length of stay in the intensive care unit, and overall costs of hospitalization. Based on currently available data, we suggest considering the use of techniques of mechanical ventilatory support that maintain, rather than suppress, spontaneous ventilatory effort, especially in patients with severe pulmonary dysfunction. PMID:15566621

  18. 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

  19. Effects of continuous negative airway pressure-related lung deflation on upper airway collapsibility.

    PubMed

    Sériès, F; Marc, I

    1993-09-01

    Continuous negative airway pressure (CNAP) causes a decrease in lung volume, which is known to increase upper airway resistance by itself. We studied how this lung volume change could modify upper airway collapsibility with five normal awake subjects. In a first trial, pressure in a nasal mask (Pm) was progressively decreased in 3- to 5-cmH2O steps (CNAP). In a second trial, changes in lung volumes resulting from CNAP were prevented by applying simultaneously an equivalent level of negative extrathoracic pressure into a poncho-type respirator [isovolumetric CNAP (CNAPisovol)]. For each trial, we examined the relationship between the maximal inspiratory airflow of each flow-limited inspiratory cycle and the corresponding Pm by least-squares linear regression analysis and determined the critical pressure. We also determined the Pm threshold corresponding to the first Pm value below which flow limitation occurred. Flow limitation was observed in each subject with CNAP but in only two subjects with CNAPisovol. In these two subjects, the Pm threshold values were -20 and -9 cmH2O with CNAP and -39 and -16 cmH2O with CNAPisovol, respectively. Critical pressures for the same two subjects were -161 and -96 cmH2O with CNAP and -202 and -197 cmH2O with CNAPisovol, respectively. We conclude that CNAP-induced decreases in lung volume increase upper airway collapsibility.

  20. Upper Airway Variation and Frequent Alcohol Consumption Can Affect Compliance With Continuous Positive Airway Pressure

    PubMed Central

    Jeong, Jong In; Kim, Hyo Yeol; Hong, Sang Duk; Ryu, Gwanghui; Kim, Su Jin; Lee, Kyung Eun; Dhong, Hun-Jong; Chung, Seung-Kyu

    2016-01-01

    Objectives Compliance with continuous positive airway pressure (CPAP) treatment remains a primary concern for improving treatment outcomes of obstructive sleep apnea. There are few studies that have considered the role of upper airway anatomy on the compliance with CPAP. We hypothesized that upper airway anatomy would influence the compliance with CPAP. Methods One hundred out of 161 consecutive patients were enrolled in this study. The following possible determinants were tested against CPAP use: demographic and anthropometric data, minimal cross-sectional area on acoustic rhinometry, cephalometric and polysomnographic data, questionnaires of Epworth sleepiness scale and Beck depression index, and histories of previous upper airway surgery, degree of nasal obstruction, daily cigarette consumption, and weekly frequency of alcohol intake. Results Univariate analysis showed that histories of previous upper airway surgery and less frequent alcohol consumption, and longer mandibular plane-hyoid length (MP-H) on cephalometry were associated with longer average daily CPAP use. After adjustment for the confounding factors with multiple linear regression analysis, alcohol consumption and MP-H were still associated with the compliance with CPAP significantly. Conclusion To improve compliance with CPAP, careful evaluations of upper airway problems and life style are important before initiating CPAP. PMID:27334512

  1. Continuous Positive Airway Pressure Strategies with Bubble Nasal Continuous Positive Airway Pressure: Not All Bubbling Is the Same: The Seattle Positive Airway Pressure System.

    PubMed

    Welty, Stephen E

    2016-12-01

    Premature neonates are predisposed to complications, including bronchopulmonary dysplasia (BPD). BPD is associated with long-term pulmonary and neurodevelopmental consequences. Noninvasive respiratory support with nasal continuous positive airway pressure (CPAP) has been recommended strongly by the American Academy of Pediatrics. However, CPAP implementation has shown at least a 50% failure rate. Enhancing nasal CPAP effectiveness may decrease the need for mechanical ventilation and reduce the incidence of BPD. Bubble nasal CPAP is better than nasal CPAP using mechanical devices and the bubbling provides air exchange in distal respiratory units. The Seattle PAP system reduces parameters that assess work of breathing.

  2. Comparison of Efficacy and Tolerance of Automatic Continuous Positive Airway Pressure Devices With the Optimum Continuous Positive Airway Pressure.

    PubMed

    Tommi, George; Aronow, Wilbert S; Sheehan, John C; McCleay, Matthew T; Meyers, Patrick G

    Patients diagnosed with obstructive sleep apnea syndrome were randomly placed on automatic continuous positive airway pressure (ACPAP) for 2 hours followed by manual titration for the rest of the night. One hundred sixty-one patients entered the study, with at least 50 patients titrated with each of 3 ACPAP devices. The optimum continuous positive airway pressure (CPAP) was defined as the lowest pressure with an apnea-hypoxia index of ≤5/hr, which ranged from 4 cm to 18 cm. Success with ACPAP was approximately 60%-80% when the optimum CPAP was 4-6 cm but fell to below 30% if the optimum CPAP was ≥8 cm (P = 0.001). Average ACPAP ranged from 2 to 10 cm below the optimum level if the optimum CPAP was ≥8 cm. Patients who responded to a low CPAP but deteriorated on higher pressures failed to respond to any of the automatic devices. We recommend that CPAP titration be performed manually before initiation of ACPAP in patients with obstructive sleep apnea. The basal pressure for ACPAP should be the optimum pressure obtained by manual titration. Limits on the upper level of ACPAP may be necessary for patients who deteriorate on higher positive pressures.

  3. Pressure-volume behaviour of the rat upper airway: effects of tongue muscle activation

    PubMed Central

    Bailey, E Fiona; Fregosi, Ralph F

    2003-01-01

    Our hypothesis was that the simultaneous activation of tongue protrudor and retractor muscles (co-activation) would constrict and stiffen the pharyngeal airway more than the independent activation of tongue protrudor muscles. Upper airway stiffness was determined by injecting known volumes of air into the sealed pharyngeal airway of the anaesthetized rat while measuring nasal pressure under control (no-stimulus) and stimulus conditions (volume paired with hypoglossal (XII) nerve stimulation). Stimulation of the whole XII nerves (co-activation) or the medial XII branches (protrudor activation) effected similar increases in total pharyngeal airway stiffness. Importantly, co-activation produced volume compression (airway narrowing) at large airway volumes (P < 0.05), but had no effect on airway dimension at low airway volumes. In comparison, protrudor activation resulted in significant volume expansion (airway dilatation) at low airway volumes and airway narrowing at high airway volumes (P < 0.05). In conclusion, both co-activation and independent protrudor muscle activation increase airway stiffness. However, their effects on airway size are complex and depend on the condition of the airway at the time of activation. PMID:12640023

  4. Advances in Positive Airway Pressure Treatment Modalities for Hypoventilation Syndromes

    PubMed Central

    Combs, Dan; Shetty, Safal; Parthasarathy, Sairam

    2014-01-01

    SYNOPSIS Rationale Positive airway pressure therapy for hypoventilation syndromes can significantly improve health-related quality of life (HR-QOL), healthcare costs, and even mortality. The sleep-disordered breathing in such individuals are quite complex and require sophisticated devices with algorithms that are designed to accurately detect and effectively treat respiratory events that includes hypoventilation, upper airway obstruction, lower airway obstruction, central apneas and central hypopneas and reduce the work of breathing while maintaining breathing comfort. Objectives The therapeutic physiological rationale for the various advanced PAP modalities and the details about the principles of operation and technology implementation are provided here. Conclusions The physiological rationale for advanced PAP modalities is sound considering the complexity of sleep-disordered breathing in patients with hypoventilation syndromes. Although such devices are increasingly used in clinical practice, the supporting clinical evidence – specifically comparative-effectiveness studies in real-life conditions -- needs to be performed. Moreover, there is much opportunity for further refining these devices that include the ability of the device to reliably monitor gas-exchange, sleep-wakefulness state, and for reducing variability in device efficacy due to provider-selected device-settings. PMID:25346650

  5. Can breathing-like pressure oscillations reverse or prevent narrowing of small intact airways?

    PubMed

    Harvey, Brian C; Parameswaran, Harikrishnan; Lutchen, Kenneth R

    2015-07-01

    Periodic length fluctuations of airway smooth muscle during breathing are thought to modulate airway responsiveness in vivo. Recent animal and human intact airway studies have shown that pressure fluctuations simulating breathing can only marginally reverse airway narrowing and are ineffective at protecting against future narrowing. However, these previous studies were performed on relatively large (>5 mm diameter) airways, which are inherently stiffer than smaller airways for which a preponderance of airway constriction in asthma likely occurs. The goal of this study was to determine the effectiveness of breathing-like transmural pressure oscillations to reverse induced narrowing and/or protect against future narrowing of smaller, more compliant intact airways. We constricted smaller (luminal diameter = 2.92 ± 0.29 mm) intact airway segments twice with ACh (10(-6) M), once while applying tidal-like pressure oscillations (5-15 cmH2O) before, during, and after inducing constriction (Pre + Post) and again while only imposing the tidal-like pressure oscillation after induced constriction (Post Only). Smaller airways were 128% more compliant than previously studied larger airways. This increased compliance translated into 196% more strain and 76% greater recovery (41 vs. 23%) because of tidal-like pressure oscillations. Larger pressure oscillations (5-25 cmH2O) caused more recovery (77.5 ± 16.5%). However, pressure oscillations applied before and during constriction resulted in the same steady-state diameter as when pressure oscillations were only applied after constriction. These data show that reduced straining of the airways before a challenge likely does not contribute to the emergence of airway hyperreactivity observed in asthma but may serve to sustain a given level of constriction.

  6. Can breathing-like pressure oscillations reverse or prevent narrowing of small intact airways?

    PubMed Central

    Harvey, Brian C.; Parameswaran, Harikrishnan

    2015-01-01

    Periodic length fluctuations of airway smooth muscle during breathing are thought to modulate airway responsiveness in vivo. Recent animal and human intact airway studies have shown that pressure fluctuations simulating breathing can only marginally reverse airway narrowing and are ineffective at protecting against future narrowing. However, these previous studies were performed on relatively large (>5 mm diameter) airways, which are inherently stiffer than smaller airways for which a preponderance of airway constriction in asthma likely occurs. The goal of this study was to determine the effectiveness of breathing-like transmural pressure oscillations to reverse induced narrowing and/or protect against future narrowing of smaller, more compliant intact airways. We constricted smaller (luminal diameter = 2.92 ± 0.29 mm) intact airway segments twice with ACh (10−6 M), once while applying tidal-like pressure oscillations (5–15 cmH2O) before, during, and after inducing constriction (Pre + Post) and again while only imposing the tidal-like pressure oscillation after induced constriction (Post Only). Smaller airways were 128% more compliant than previously studied larger airways. This increased compliance translated into 196% more strain and 76% greater recovery (41 vs. 23%) because of tidal-like pressure oscillations. Larger pressure oscillations (5–25 cmH2O) caused more recovery (77.5 ± 16.5%). However, pressure oscillations applied before and during constriction resulted in the same steady-state diameter as when pressure oscillations were only applied after constriction. These data show that reduced straining of the airways before a challenge likely does not contribute to the emergence of airway hyperreactivity observed in asthma but may serve to sustain a given level of constriction. PMID:25953836

  7. Fluid-Structure Analysis of Opening Phenomena in a Collapsible Airway

    NASA Astrophysics Data System (ADS)

    Ghadiali, Samir N.; Banks, Julie; Swarts, J. Douglas

    2003-11-01

    Several physiological functions require the opening of collapsed respiratory airways. For example, the Eustachian tube (ET), which connects the nasopharynx with the middle ear (ME), must be periodically opened to maintain ambient ME pressures. These openings normally occur during swallowing when muscle contraction deforms the surrounding soft tissue. The inability to open the ET results in the most common and costly ear disease in children, Otitis Media. Although tissue-based treatments have been purposed, the influence of the various tissue mechanical properties on flow phenomena has not been investigated. A computational model of ET opening was developed using in-vivo structural data to investigate these fluid-structure interactions. This model accounts for both tissue deformation and the resulting airflow in a non-circular conduit. Results indicate that ET opening is more sensitive to the applied muscle forces than elastic tissue properties. These models have therefore identified how different tissue elements alter ET opening phenomena, which elements should be targeted for treatment and the optimal mechanical properties of these tissue constructs. Research supported by NIH grant DC005345.

  8. Validation of airway resistance models for predicting pressure loss through anatomically realistic conducting airway replicas of adults and children.

    PubMed

    Borojeni, Azadeh A T; Noga, Michelle L; Martin, Andrew R; Finlay, Warren H

    2015-07-16

    This work describes in vitro measurement of the total pressure loss at varying flow rate through anatomically realistic conducting airway replicas of 10 children, 4 to 8 years old, and 5 adults. Experimental results were compared with analytical predictions made using published airway resistance models. For the adult replicas, the model proposed by van Ertbruggen et al. (2005. J. Appl. Physiol. 98, 970-980) most accurately predicted central conducting airway resistance for inspiratory flow rates ranging from 15 to 90 L/min. Models proposed by Pedley et al. (1970. J. Respir. Physiol. 9, 371-386) and by Katz et al. (2011. J. Biomech. 44, 1137-1143) also provided reasonable estimates, but with a tendency to over predict measured pressure loss for both models. For child replicas, the Pedley and Katz models both provided good estimation of measured pressure loss at flow rates representative of resting tidal breathing, but under predicted measured values at high inspiratory flow rate (60 L/min). The van Ertbruggen model, developed based on flow simulations performed in an adult airway model, tended to under predict measured pressure loss through the child replicas across the range of flow rates studied (2 to 60 L/min). These results are intended to provide guidance for selection of analytical pressure loss models for use in predicting airway resistance and ventilation distribution in adults and children.

  9. [Continuous positive airways pressure treatment for obstructive sleep apnoea].

    PubMed

    Antone, E; Gilbert, M; Bironneau, V; Meurice, J C

    2015-04-01

    Continuous positive airway pressure (CPAP) still remains the most frequently used and the most efficient treatment for obstructive sleep apnea syndrome. However, its efficiency is conditioned by healthcare quality depending on many factors such as medical specificities of the patients as well as the severity of sleep-related breathing disorders. In order to optimize CPAP efficiency, it is necessary to be aware of the functional abilities of the different devices, and to perform a close monitoring of the patients, particularly during the first weeks of treatment, by maximally using the data provided by the CPAP apparatus. Some questions remain unsolved, such as the impact of nasal CPAP on glucose metabolism or cardiovascular prognosis. Furthermore, the strategy of CPAP use should be improved according to future results of studies dedicated to the interest of home telemonitoring and taking into account the validated mode of CPAP initiation.

  10. Vascular tracers alter hemodynamics and airway pressure in anesthetized sheep

    SciTech Connect

    Albertine, K.H.; Staub, N.C.

    1986-11-01

    The technique of vascular labeling was developed to mark sites of increased microvascular permeability. We used the vascular labeling technique in anesthetized sheep and found that hemodynamics and airway pressure were adversely affected by intraarterial infusions of two vascular tracers. Monastral blue (nine sheep) immediately caused systemic arterial hypotension, pulmonary arterial hypertension, and bronchoconstriction. All three physiological responses were partially blocked by a cyclooxygenase inhibitor (indomethacin) but not by an H1-antihistamine (chlorpheniramine). Colloidal gold (nine sheep) caused immediate, but less dramatic, pulmonary arterial hypertension which was not attenuated by the blocking agents. We conclude that these two vascular tracers caused detrimental physiological side effects in sheep at the usual doses used to label injured microvessels in other species.

  11. Pediatric Positive Airway Pressure Adherence in Obstructive Sleep Apnea Enhanced by Family Member Positive Airway Pressure Usage

    PubMed Central

    Puri, Pooja; Ross, Kristie R.; Mehra, Reena; Spilsbury, James C.; Li, Hong; Levers-Landis, Carolyn E.; Rosen, Carol L.

    2016-01-01

    Study Objectives: Adherence to positive airway pressure (PAP) therapy for obstructive sleep apnea (OSA) remains a challenge in children. We hypothesized that the presence of another family member on PAP therapy (parent, sibling, other family member) would be associated with better adherence in the child. Methods: We conducted a retrospective chart review to identify children < 18 years of age who had a new diagnosis of OSA between Jan 2011 and May 2013. Outcomes were objective PAP adherence at 1 week, 1 month, and 3 months. Potential predictors included family member on PAP therapy, patient demographics, and clinical characteristics. Group differences between children with and without a family member on PAP therapy were determined using χ2 test and Wilcoxon two-sample test. PAP adherence measures at each time point and patterns of change across time between the two groups were examined using mixed-effects models. Results: The final analytic sample included 56 children: age 13.2 ± 3.7 years, 60% male, 67% African American, 65% obese, and 32% with developmental disabilities. The mean obstructive apnea-hypopnea index was 25.2 ± 28.7, and 19 (33%) had a family member on PAP therapy. Overall PAP adherence was 2.8 ± 2.4 h/night at 3 months. At month 3, the group with a family member on PAP therapy had significantly greater average nightly PAP use on all nights (3.6 ± 0.6 vs. 2.3 ± 0.39) and on nights used (4.8 ± 0.6 vs. 3.8 ± 0.40); (p value = 0.04). Conclusions: Overall PAP adherence was low, but having a family member on PAP therapy as a “role model” was associated with better adherence. Commentary: A commentary on this article appears in this issue on page 941. Citation: Puri P, Ross KR, Mehra R, Spilsbury JC, Li H, Levers-Landis CE, Rosen CL. Pediatric positive airway pressure adherence in obstructive sleep apnea enhanced by family member positive airway pressure usage. J Clin Sleep Med 2016;12(7):959–963. PMID:27092699

  12. Mouth leak with nasal continuous positive airway pressure increases nasal airway resistance.

    PubMed

    Richards, G N; Cistulli, P A; Ungar, R G; Berthon-Jones, M; Sullivan, C E

    1996-07-01

    Nasal congestion, dry nose and throat, and sore throat affect approximately 40% of patients using nasal continuous positive airway pressure (CPAP). The mechanisms causing nasal symptoms are unclear, but mouth leaks causing high unidirectional nasal airflow may be important. We conducted a study to investigate the effects of mouth leak and the influence of humidification on nasal resistance in normal subjects. Nasal resistance was measured with posterior rhinomanometry in six normal subjects who deliberately produced a mouth leak for 10 min while using nasal CPAP. Nasal resistance was measured regularly for 20 min after the challenge. A series of tests were performed using air at differing temperatures and humidities. There was no change in nasal resistance when subjects breathed through their noses while on CPAP, but a mouth leak caused a large increase in resistance (at a flow of 0.5 L/s) from a baseline mean of 2.21 cm H2O/L/s to a maximum mean of 7.52 cm H2O/L/s at 1 min after the challenge. Use of a cold passover humidifier caused little change in the response (maximum mean: 8.27 cm H2O/L/s), but a hot water bath humidifier greatly attenuated the magnitude (maximum mean: 4.02 cm H2O/L/s) and duration of the response. Mouth leak with nasal CPAP leads to high unidirectional nasal airflow, which causes a large increase in nasal resistance. This response can be largely prevented by fully humidifying the inspired air.

  13. Pressure-driven opening of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Chaban, Vitaly V.; Prezhdo, Oleg V.

    2016-03-01

    The closing and opening of carbon nanotubes (CNTs) is essential for their applications in nanoscale chemistry and biology. We report reactive molecular dynamics simulations of CNT opening triggered by internal pressure of encapsulated gas molecules. Confined argon generates 4000 bars of pressure inside capped CNT and lowers the opening temperature by 200 K. Chemical interactions greatly enhance the efficiency of CNT opening: fluorine-filled CNTs open by fluorination of carbon bonds at temperature and pressure that are 700 K and 1000 bar lower than for argon-filled CNTs. Moreover, pressure induced CNT opening by confined gases leaves the CNT cylinders intact and removes only the fullerene caps, while the empty CNT decomposes completely. In practice, the increase in pressure can be achieved by near-infrared light, which penetrates through water and biological tissues and is absorbed by CNTs, resulting in rapid local heating. Spanning over a thousand of bars and Kelvin, the reactive and non-reactive scenarios of CNT opening represent extreme cases and allow for a broad experimental control over properties of the CNT interior and release conditions of the confined species. The detailed insights into the thermodynamic conditions and chemical mechanisms of the pressure-induced CNT opening provide practical guidelines for the development of novel nanoreactors, catalysts, photo-catalysts, imaging labels and drug delivery vehicles.

  14. Adherence to Continuous Positive Airway Pressure in Existing Users: Self-Efficacy Enhances the Association between Continuous Positive Airway Pressure and Adherence

    PubMed Central

    Dzierzewski, Joseph M.; Wallace, Douglas M.; Wohlgemuth, William K.

    2016-01-01

    Study Objectives: Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a common sleep disorder associated with a myriad of sequelae. OSAHS is effectively treated with continuous positive airway pressure (CPAP) therapy. However, fewer than 50% of patients are compliant with their CPAP therapy prescriptions. The current study sought to explore an integrated, biopsychological approach to CPAP adherence among experienced CPAP users. Methods: We performed a retrospective, cross-sectional analysis of a cohort of veterans with a diagnosis of OSAHS (n = 191) who were prescribed CPAP therapy and returned for adherence download at the Miami VA Sleep Clinic. The relationships between biomedical characteristics (e.g., CPAP pressure, self-reported sleepiness, and change in sleep efficiency) and psychological factors (e.g., self-efficacy beliefs and psychological diagnoses) and objectively measured CPAP use were examined to determine whether psychological factors moderated the relationships between biomedical characteristics and CPAP adherence. Results: Hierarchical regression analyses predicting CPAP adherence (adjusting for time since CPAP prescription, age, education, prescribed CPAP pressure, daytime sleepiness, changes in sleep efficiency with CPAP, and psychiatric conditions) revealed the following: (1) CPAP self-efficacy and CPAP pressure were positively related to adherence, and (2) CPAP self-efficacy moderates the relationship between CPAP pressure and CPAP adherence. Conclusions: There was no relationship between CPAP pressure and adherence in individuals with low self-efficacy beliefs. However, for individuals with high self-efficacy beliefs, there was a significant positive relationship between CPAP pressure and adherence. Self-efficacy beliefs appear to be a prime target for focused interventions aimed at improving CPAP adherence among those individuals with higher pressure prescriptions. Citation: Dzierzewski JM, Wallace DM, Wohlgemuth WK. Adherence to continuous

  15. Intermittent positive airway pressure to manage hypoxia during one-lung anaesthesia.

    PubMed

    Russell, W J

    2009-05-01

    The effect of intermittent positive airway pressure to the non-ventilated lung was assessed in 10 patients who desaturated during one-lung ventilation. Once their saturation fell below 95% they were given a slow inflation of 2 l/min of oxygen into the non-ventilated lung for two seconds. This was repeated every 10 seconds for five minutes or until the saturation rose to 98%, whichever was sooner. The initial mean SpO2 was 89.3% +/- 4.2%. All 10 patients had an increase in saturation. The mean saturation following intermittent positive airway pressure was 96.5% +/- 1.6% (P < 0.0001). Similarly, the mean oxygen tension rose from 67.2 +/- 12.8 mmHg to 98.9 +/- 19.8 mmHg. Intermittent positive airway pressure should be considered for patients who desaturate while undergoing one-lung ventilation.

  16. The impacts of open-mouth breathing on upper airway space in obstructive sleep apnea: 3-D MDCT analysis.

    PubMed

    Kim, Eun Joong; Choi, Ji Ho; Kim, Kang Woo; Kim, Tae Hoon; Lee, Sang Hag; Lee, Heung Man; Shin, Chol; Lee, Ki Yeol; Lee, Seung Hoon

    2011-04-01

    Open-mouth breathing during sleep is a risk factor for obstructive sleep apnea (OSA) and is associated with increased disease severity and upper airway collapsibility. The aim of this study was to investigate the effect of open-mouth breathing on the upper airway space in patients with OSA using three-dimensional multi-detector computed tomography (3-D MDCT). The study design included a case-control study with planned data collection. The study was performed at a tertiary medical center. 3-D MDCT analysis was conducted on 52 patients with OSA under two experimental conditions: mouth closed and mouth open. Under these conditions, we measured the minimal cross-sectional area of the retropalatal and retroglossal regions (mXSA-RP, mXSA-RG), as well as the upper airway length (UAL), defined as the vertical dimension from hard palate to hyoid. We also computed the volume of the upper airway space by 3-D reconstruction of both conditions. When the mouth was open, mXSA-RP and mXSA-RG significantly decreased and the UAL significantly increased, irrespective of the severity of OSA. However, between the closed- and open-mouth states, there was no significant change in upper airway volume at any severity of OSA. Results suggest that the more elongated and narrow upper airway during open-mouth breathing may aggravate the collapsibility of the upper airway and, thus, negatively affect OSA severity.

  17. Effect of Continuous Positive Airway Pressure on Airway Inflammation and Oxidative Stress in Patients with Obstructive Sleep Apnea

    PubMed Central

    Tichanon, Promsrisuk; Sopida, Santamit; Orapin, Pasurivong; Watchara, Boonsawat; Banjamas, Intarapoka

    2016-01-01

    Background. Airway inflammation and oxidative stress may be linked in obstructive sleep apnea (OSA) patients. We determined the effectiveness of continuous positive airway pressure (CPAP) therapy in reducing fractional exhaled nitric oxide (FeNO) and malondialdehyde (MDA) levels in OSA patients. Methods. Thirteen patients with OSA and 13 normal controls were recruited. FeNO and MDA levels were measured in the controls and in OSA patients before and after three months of CPAP therapy. Results. FeNO and MDA levels were higher in the patients compared to the age and gender matched controls (FeNO: 25.9 ± 5.0 versus 17.5 ± 5.9 ppb, P < 0.001; MDA: 14.6 ± 7.8 versus 2.1 ± 0.3 μmol/L, P < 0.001). FeNO and MDA levels were lower post-CPAP compared to pre-CPAP (FeNO: 25.9 ± 5.0 versus 17.0 ± 2.3 ppb, P < 0.001; MDA: 14.6 ± 7.8 versus 10.0 ± 6.4 μmol/L, P < 0.01). Apnea-hypopnea index (15.9 ± 6.6 versus 4.1 ± 2.1/h, P < 0.001) and mean arterial pressure (P < 0.01) decreased following CPAP treatment. Daytime mean SpO2 (P < 0.05) increased. Conclusion. Our study demonstrates that CPAP therapy yields clinical benefits by reducing upper airway inflammation and oxidative stress in OSA patients. PMID:27445526

  18. A mobile, web-based system can improve positive airway pressure adherence.

    PubMed

    Hostler, Jordanna M; Sheikh, Karen L; Andrada, Teotimo F; Khramtsov, Andrei; Holley, Paul R; Holley, Aaron B

    2017-04-01

    SleepMapper is a mobile, web-based system that allows patients to self-monitor their positive airway pressure therapy, and provides feedback and education in real time. In addition to the usual, comprehensive support provided at our clinic, we gave the SleepMapper to 30 patients initiating positive airway pressure. They were compared with patients initiating positive airway pressure at our clinic without SleepMapper (controls) to determine whether SleepMapper affected adherence. A total of 61 patients had polysomnographic and adherence data analysed, 30 were given SleepMapper and 31 received our standard of care. The two groups were well matched at baseline to include no significant differences in age, apnea-hypopnea index, percentage receiving split-night polysomnographs and starting pressures. Patients in the control group received significantly more non-benzodiazepine sedative hypnotics the night of their polysomnography and during positive airway pressure initiation. At 11 weeks, patients in the SleepMapper group had a greater percentage of nights with any use (78.0 ± 22.0 versus 55.5 ± 24.0%; P < 0.001) and >4 h positive airway pressure use (78.0 ± 22.0 versus 55.5 ± 24.0%; P = 0.02). There was a trend toward more patients in the SleepMapper group achieving >4 h of use for at least 70% of nights [9/30 (30%) versus 3/31 (9.7%); P = 0.06]. In multivariate linear regression, the SleepMapper remained significantly associated with percentage of nights >4 h positive airway pressure use (β coefficient = 0.18; P = 0.02). Added to our usual, comprehensive programme to maximize positive airway pressure adherence in new users, the SleepMapper was independently associated with an 18% increase in nights >4 h of use.

  19. Motivational Interviewing (MINT) Improves Continuous Positive Airway Pressure (CPAP) Acceptance and Adherence: A Randomized Controlled Trial

    ERIC Educational Resources Information Center

    Olsen, Sara; Smith, Simon S.; Oei, Tian P. S.; Douglas, James

    2012-01-01

    Objective: Adherence to continuous positive airway pressure (CPAP) therapy for obstructive sleep apnoea (OSA) is poor. We assessed the effectiveness of a motivational interviewing intervention (motivational interview nurse therapy [MINT]) in addition to best practice standard care to improve acceptance and adherence to CPAP therapy in people with…

  20. Sleep · 7: Positive airway pressure therapy for obstructive sleep apnoea/hypopnoea syndrome

    PubMed Central

    Gordon, P; Sanders, M

    2005-01-01

    The use of continuous positive airway pressure (CPAP) in treating symptoms associated with OSAHS is reviewed. Although it is an imperfect intervention, it continues to evolve and improve in such a way that patients who would not have been able to use this treatment even in the recent past can benefit from it today. PMID:15618587

  1. Airway dynamics in COPD patients by within-breath impedance tracking: effects of continuous positive airway pressure.

    PubMed

    Lorx, András; Czövek, Dorottya; Gingl, Zoltán; Makan, Gergely; Radics, Bence; Bartusek, Dóra; Szigeti, Szabolcs; Gál, János; Losonczy, György; Sly, Peter D; Hantos, Zoltán

    2017-02-01

    Tracking of the within-breath changes of respiratory mechanics using the forced oscillation technique may provide outcomes that characterise the dynamic behaviour of the airways during normal breathing.We measured respiratory resistance (Rrs) and reactance (Xrs) at 8 Hz in 55 chronic obstructive pulmonary disease (COPD) patients and 20 healthy controls, and evaluated Rrs and Xrs as functions of gas flow (V') and volume (V) during normal breathing cycles. In 12 COPD patients, additional measurements were made at continuous positive airway pressure (CPAP) levels of 4, 8, 14 and 20 hPa.The Rrs and Xrsversus V' and V relationships displayed a variety of loop patterns, allowing characterisation of physiological and pathological processes. The main outcomes emerging from the within-breath analysis were the Xrsversus V loop area (AXV) quantifying expiratory flow limitation, and the tidal change in Xrs during inspiration (ΔXI) reflecting alteration in lung inhomogeneity in COPD. With increasing CPAP, AXV and ΔXI approached the normal ranges, although with a large variability between individuals, whereas mean Rrs remained unchanged.Within-breath tracking of Rrs and Xrs allows an improved assessment of expiratory flow limitation and functional inhomogeneity in COPD; thereby it may help identify the physiological phenotypes of COPD and determine the optimal level of respiratory support.

  2. Obstructive sleep apnoea in the elderly: role of continuous positive airway pressure treatment.

    PubMed

    Martínez-García, Miguel Ángel; Chiner, Eusebi; Hernández, Luis; Cortes, Jose Pascual; Catalán, Pablo; Ponce, Silvia; Diaz, Jose Ramón; Pastor, Ester; Vigil, Laura; Carmona, Carmen; Montserrat, Josep Maria; Aizpuru, Felipe; Lloberes, Patricia; Mayos, Mercedes; Selma, Maria José; Cifuentes, Jose Fernando; Muñoz, Alvaro

    2015-07-01

    Almost all the information about the effect of continuous positive airway pressure (CPAP) in patients with obstructive sleep apnoea (OSA) comes from clinical trials involving only middle-aged patients. The objective of this study was to assess the effect of CPAP treatment in elderly patients with severe OSA on clinical, quality-of-life and neurocognitive spheres. We performed an open-label, randomised, multicentre clinical trial in a consecutive clinical cohort of 224 elderly (≥70 years old) patients with confirmed severe OSA (apnoea-hypopnea index ≥30) randomised to receive CPAP (n=115) or no CPAP (n=109) for 3 months. A sleep study was performed by either full polysomnography or respiratory polygraphy. CPAP titration was performed by an autoCPAP device. The primary endpoint was quality of life (Quebec Sleep Questionnaire) and secondary endpoints included sleep-related symptoms, presence of anxiety/depression, office-based blood pressure and some neurocognitive tests. The mean±sd age was 75.5±3.9 years. The CPAP group achieved a greater improvement in all quality-of-life domains (p<0.001; effect size: 0.41-0.98), sleep-related symptoms (p<0.001; effect size 0.31-0.91) as well as anxiety (p=0.016; effect size 0.51) and depression (p<0.001; effect size: 0.28) indexes and some neurocognitive tests (digit symbol test (p=0.047; effect size: 0.20) and Trail Making Test A (p=0.029; effect size: 0.44)) in an intention-to-treat analysis. In conclusion, CPAP treatment resulted in an improvement in quality of life, sleep-related symptoms, anxiety and depression indexes and some neurocognitive aspects in elderly people with severe OSA.

  3. 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

  4. New developments in the use of positive airway pressure for obstructive sleep apnea

    PubMed Central

    Boeder, Schafer; Malhotra, Atul; Patel, Sanjay R.

    2015-01-01

    Obstructive sleep apnea (OSA) is a disorder which afflicts a large number of individuals around the world. OSA causes sleepiness and is a major cardiovascular risk factor. Since its inception in the early 1980’s, continuous positive airway pressure (CPAP) has emerged as the major treatment of OSA, and it has been shown to improve sleepiness, hypertension, and a number of cardiovascular indices. Despite its successes, adherence with treatment remains a major limitation. Herein we will review the evidence behind the use of positive airway pressure (PAP) therapy, its various modes, and the methods employed to improve adherence. We will also discuss the future of PAP therapy in OSA and personalization of care. PMID:26380760

  5. Efficacy of the New Perilaryngeal Airway (CobraPLA™) Versus the Laryngeal Mask Airway (LMA™) to Improve Oropharyngeal Leak Pressure in Obese and Overweight Patients

    PubMed Central

    Yaghoobi, Siamak; Abootorabi, Seyed Mohamadreza; Kayalha, Hamid; Van Zundert, Tom C

    2015-01-01

    Background: This study aimed to evaluate the applicability of Cobra perilaryngeal airway (Cobra PLA™) for obese patients under general anesthesia and also to compare the results with those of classic laryngeal mask airway (LMA™). Materials and Methods: Seventy-three overweight and obese patients were included in this study. The patients were randomly assigned to LMA™ or Cobra PLA™ groups. Time required for intubation, successful intubation attempt, airway sealing pressure and incidence of complications including blood staining, sore throat and dysphagia were assessed and noted. Results: Thirty-six and 37 patients were randomly allocated to LMA™ and Cobra PLA™ groups, respectively. Most patients were males and had Mallampati Class II airway in both groups. The first attempt and overall insertion success for Cobra PLA™ was significantly higher compared to LMA (P<0.05). Airway insertion was more successful (P = 0.027; 94% vs. 77%) with Cobra PLA™. Insertion times were similar with Cobra PLA™ and LMA™ (Cobra PLA™, 29.94±16.35s; LMA™, 27.00±7.88s). The oropharyngeal leak pressure in the Cobra PLA™ group (24.80±0.90 H2O) was significantly higher than that in LMA™ group (19±1 H2O, p<0.001). Sore throat was more frequent in the LMA™ group although it did not reach statistical significance (Fisher’s exact test, P = 0.33). Blood staining on airway tube was seen in both groups with a higher incidence in the Cobra PLA™ group (Fisher’s Exact test, P = 0.02). Incidence of dysphagia was not different between the two groups. Conclusion: CobraPLA™ was found to be safe with low complications. It provided better airway sealing with high rate of the first insertion success for use in obese and overweight patients. This study recommends the use of CobraPLA™ as a rescue device in emergency situations for obese and overweight patients. PMID:26221151

  6. Negative Expiratory Pressure Technique: An Awake Test to Measure Upper Airway Collapsibility in Adolescents

    PubMed Central

    Carrera, Helena Larramona; Marcus, Carole L.; McDonough, Joseph M.; Morera, Joan C. Oliva; Huang, Jingtao; Farre, Ramon; Montserrat, Josep M.

    2015-01-01

    Study Objectives: Upper airway (UA) collapsibility is a major pathophysiologic feature of the obstructive sleep apnea syndrome (OSAS). In adolescents, it is measured by obtaining the slope of pressure-flow relationship (SPF) while applying negative nasal pressure during sleep. An easier technique to assess UA collapsibility, consisting of application of negative expiratory pressure (NEP) during wakefulness, has demonstrated differences between control and OSAS subjects. We hypothesized that the NEP technique would correlate with SPF as a measurement of UA collapsibility in adolescents. Design: During wakefulness, NEP of −5 cm H2O in the seated and supine position was applied during the first second of expiration. The area under the expiratory flow-volume curve during NEP was compared to tidal breathing (RatioNEP). In addition, adolescents underwent SPF measurements during sleep. Two SPF techniques were performed to measure the activated and relatively hypotonic UA. Setting: Pediatric sleep laboratory. Participants: Seven adolescents with OSAS and 20 controls. Results: In the seated position, there was a correlation between RatioNEP and both hypotonic SPF (r = −0.39, P = 0.04) and activated SPF (r = −0.62, P = 0.001). In the supine position, there was a correlation between RatioNEP and activated SPF (r = −0.43, P = 0.03) and a trend for hypotonic SPF (r = −0.38, P = 0.06). Conclusions: The negative expiratory pressure (NEP) technique correlates with the hypotonic and activated slope of pressure-flow relationship measurements. The seated position showed the strongest correlation. The NEP technique can be used as an alternative method to evaluate upper airway collapsibility in adolescents. Citation: Carrera HL, Marcus CL, McDonough JM, Morera JC, Huang J, Farre R, Montserrat JM. Negative expiratory pressure technique: an awake test to measure upper airway collapsibility in adolescents. SLEEP 2015;38(11):1783–1791. PMID:26158888

  7. Airway Pressure Release Ventilation and High-Frequency Oscillatory Ventilation: Potential Strategies to Treat Severe Hypoxemia and Prevent Ventilator-Induced Lung Injury.

    PubMed

    Facchin, Francesca; Fan, Eddy

    2015-10-01

    Although lifesaving, mechanical ventilation can itself be responsible for damage to lung parenchyma. This ventilator-induced lung injury is especially observed in already injured lungs of patients with ARDS. New ventilatory approaches are needed to safely treat patients with ARDS, and recent studies have suggested the potential utility of open-lung strategies. Airway pressure release ventilation (APRV) and high-frequency oscillatory ventilation (HFOV) are 2 different open-lung strategies that have been proposed to treat refractory hypoxemic respiratory failure while preventing ventilator-induced lung injury. APRV provides increased airway pressure as a potential recruitment mechanism and allows spontaneous breathing, with the potential benefits of decreased sedation, shorter duration of mechanical ventilation, and improvement in cardiac performance. HFOV delivers very small tidal volumes, to prevent volutrauma, at a constant (relatively high) mean airway pressure, thus avoiding atelectrauma. Despite their theoretical benefits, the utility of APRV and HFOV remains unproven and controversial for the routine treatment of ARDS in adult patients. This review is focused on the theoretical and practical aspects of APRV and HFOV, provides an overview of the current evidence, and addresses their possible use in the treatment of ARDS.

  8. Use of Biphasic Continuous Positive Airway Pressure in Premature Infant with Cleft Lip–Cleft Palate

    PubMed Central

    George, Lovya; Jain, Sunil K.

    2015-01-01

    Preterm infants (PIs) often require respiratory support due to surfactant deficiency. Early weaning from mechanical ventilation to noninvasive respiratory support decreases ventilation-associated irreversible lung damage. This wean is particularly challenging in PIs with cleft lip and cleft palate due to anatomical difficulties encountered in maintaining an adequate seal for positive pressure ventilation. PI with a cleft lip and palate often fail noninvasive respiratory support and require continued intubation and mechanical ventilation. We are presenting the first case report of a PI with cleft lip and palate who was managed by biphasic nasal continuous positive airway pressure. PMID:26495158

  9. Management of severe obstructive sleep apnea using mandibular advancement devices with auto continuous positive airway pressures

    PubMed Central

    Upadhyay, Rashmi; Dubey, Abhishek; Kant, Surya; Singh, Balendra Pratap

    2015-01-01

    The use of continuous positive airway pressures (CPAP) is considered standard treatment of moderate to severe obstructive sleep apnea (OSA). Treatment of the disease poses a great challenge not only for its diagnostic purpose but also for its treatment part. In about 29-83% of the patients, treatment is difficult because of non-compliance resulting due to high pressures, air leaks and other related issues. In such situations, alternative methods of treatment need to be looked for so as to ascertain better management. Mandibular advancement devices along with CPAP may show better treatment outcome in specific situations. PMID:25814802

  10. Airway pressure release ventilation in morbidly obese surgical patients with acute lung injury and acute respiratory distress syndrome.

    PubMed

    Testerman, George M; Breitman, Igal; Hensley, Sarah

    2013-03-01

    Morbidly obese patients with body mass index greater than 40 kg/m(2) and respiratory failure requiring critical care services are increasingly seen in trauma and acute care surgical centers. Baseline respiratory pathophysiology including decreased pulmonary compliance with dependent atelectasis and abnormal ventilation-perfusion relationships predisposes these patients to acute lung injury (ALI) and adult respiratory distress syndrome (ARDS) as well as prolonged stays in the intensive care unit. Airway pressure release ventilation (APRV) is an increasingly used alternative mode for salvage therapy in patients with hypoxemic respiratory failure that also provides lung protection from ventilator-induced lung injury. APRV provides the conceptual advantage of an "open lung" approach to ventilation that may be extended to the morbidly obese patient population with ALI and ARDS. We discuss the theoretical benefits and a recent clinical experience of APRV ventilation in the morbidly obese patient with respiratory failure at a Level I trauma, surgical critical care, and acute care surgery center.

  11. Lung Volume and Continuous Positive Airway Pressure Requirements in Obstructive Sleep Apnea

    PubMed Central

    Heinzer, Raphael C.; Stanchina, Michael L.; Malhotra, Atul; Fogel, Robert B.; Patel, Sanjay R.; Jordan, Amy S.; Schory, Karen; White, David P.

    2005-01-01

    Previous studies have demonstrated that lung volume during wakefulness influences upper airway size and resistance, particularly in patients with sleep apnea. We sought to determine the influence of lung volume on the level of continuous positive airway pressure (CPAP) required to prevent flow limitation during non-REM sleep in subjects with sleep apnea. Seventeen subjects (apnea–hypopnea index, 42.6 ± 6.2 [SEM]) were studied during stable non-REM sleep in a rigid head-out shell equipped with a positive/negative pressure attachment for manipulation of extrathoracic pressure. An epiglottic pressure catheter plus a mask/pneumotachometer were used to assess flow limitation. When lung volume was increased by 1,035 ± 22 ml, the CPAP level could be decreased from 11.9 ± 0.7 to 4.8 ± 0.7 cm H2O (p < 0.001) without flow limitation. The decreased CPAP at the same negative extrathoracic pressure yielded a final lung volume increase of 421 ± 36 ml above the initial value. Conversely, when lung volume was reduced by 732 ± 74 ml (n = 8), the CPAP level had to be increased from 11.9 ± 0.7 to 17.1 ± 1.0 cm H2O (p < 0.001) to prevent flow limitation, with a final lung volume decrease of 567 ± 78 ml. These results demonstrate that relatively small changes in lung volume have an important effect on the upper airway in subjects with sleep apnea during non-REM sleep. PMID:15817803

  12. Diastolic function and functional capacity after a single session of continuous positive airway pressure in patients with compensated heart failure

    PubMed Central

    Bussoni, Marjory Fernanda; Guirado, Gabriel Negretti; Matsubara, Luiz Shiguero; Roscani, Meliza Goi; Polegato, Bertha Furlan; Minamoto, Suzana Tanni; Bazan, Silméia Garcia Zanati; Matsubara, Beatriz Bojikian

    2014-01-01

    OBJECTIVE: The effects of acute continuous positive airway pressure therapy on left ventricular diastolic function and functional capacity in patients with compensated systolic heart failure remain unclear. METHODS: This randomized, double-blind, placebo-controlled clinical trial included 43 patients with heart failure and a left ventricular ejection fraction <0.50 who were in functional classes I-III according to the New York Heart Association criteria. Twenty-three patients were assigned to continuous positive airway pressure therapy (10 cmH2O), while 20 patients received placebo with null pressure for 30 minutes. All patients underwent a 6-minute walk test (6MWT) and Doppler echocardiography before and immediately after intervention. Clinicaltrials.gov: NCT01088854. RESULTS: The groups had similar clinical and echocardiographic baseline variables. Variation in the diastolic function index (e′) after intervention was associated with differences in the distance walked in both groups. However, in the continuous positive airway pressure group, this difference was greater (continuous positive airway pressure group: Δ6MWT = 9.44+16.05×Δe′, p = 0.002; sham group: Δ6MWT = 7.49+5.38×Δe′; p = 0.015). There was a statistically significant interaction between e′ index variation and continuous positive airway pressure for the improvement of functional capacity (p = 0.020). CONCLUSIONS: Continuous positive airway pressure does not acurately change the echocardiographic indexes of left ventricle systolic or diastolic function in patients with compensated systolic heart failure. However, 30-minute continuous positive airway pressure therapy appears to have an effect on left ventricular diastolic function by increasing functional capacity. PMID:24838902

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

    PubMed Central

    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. PMID:26604837

  14. Oscillatory pressure wave transmission from the upper airway to the carotid artery.

    PubMed

    Howitt, Lauren; Kairaitis, Kristina; Kirkness, Jason P; Garlick, Sarah R; Wheatley, John R; Byth, Karen; Amis, Terence C

    2007-11-01

    Snoring-associated vibration energy transmission from the upper airway to the carotid artery has been hypothesized as a potential atherosclerotic plaque initiating/rupturing event that may provide a pathogenic mechanism linking snoring and embolic stroke. We examined transmission of oscillatory pressure waves from the pharyngeal lumen to the common carotid artery wall and lumen in seven male, anesthetized, spontaneously breathing New Zealand White rabbits. Airflow was monitored via a pneumotachograph inserted in series in the intact trachea. Fifteen 20-s runs of, separately, 40-, 60-, and 90-Hz oscillatory pressure waves [pressure amplitude in the trachea (Ptr(amp)), amplitude 2-20 cmH(2)O] were generated by a loudspeaker driven by a sine wave generator and amplifier and superimposed on tidal breathing via the cranial tracheal connector. Pressure transducer-tipped catheters measured pressure amplitudes in the tissues adjacent to the common carotid artery bifurcation (Pcti(amp)) and within the lumen (carotid sinus; Pcs(amp)). Data were analyzed using power spectrum analysis and linear mixed-effects statistical modeling. Both the frequency (f) and amplitude of the injected pressure wave influenced Pcti(amp) and Pcs(amp), in that ln Pcti(amp) = 1.2(Ptr(amp)) + 0.02(f) - 5.2, and ln Pcs(amp) = 0.6(Ptr(amp)) + 0.02(f) - 4.9 (both P < 0.05). Across all frequencies tested, transfer of oscillatory pressure across the carotid artery wall was associated with an amplitude gain, as expressed by a Pcs(amp)-to-Pcti(amp) ratio of 1.8 +/- 0.3 (n = 6). Our findings confirm transmission of oscillatory pressure waves from the upper airway lumen to the peripharyngeal tissues and across the carotid artery wall to the lumen. Further studies are required to establish the role of this incident energy in the pathogenesis of carotid artery vascular disease.

  15. Expiratory Positive Airway Pressure for Sleep Apnea after Stroke: A Randomized, Crossover Trial

    PubMed Central

    Wheeler, Natalie C.; Wing, Jeffrey J.; O'Brien, Louise M.; Hughes, Rebecca; Jacobs, Teresa; Claflin, Edward; Chervin, Ronald D.; Brown, Devin L.

    2016-01-01

    Study Objectives: Obstructive sleep apnea (OSA) is common after stroke and predicts poor outcomes. Continuous positive airway pressure (CPAP) treats OSA but is generally poorly tolerated by stroke patients. We assessed whether nasal expiratory positive airway pressure (EPAP), an alternative to CPAP, may be an effective option after acute stroke. Methods: We conducted a randomized, controlled, two-period crossover study in which each acute ischemic stroke patient received 1 night of EPAP and 1 night without EPAP while OSA was monitored with a validated device, the Watch-PAT 200. Linear repeated- measures analyses were conducted. Sample size calculations indicated that 18 subjects would be required to detect a 10-point or larger average reduction in the apnea-hypopnea index (AHI, the primary outcome), with use of EPAP, with power ≥ 80% and α = 0.05. Results: Among the 19 subjects who completed the protocol, nasal EPAP treatment was associated with a nonsignificant absolute difference in AHI of −5.73 events/h in the primary analysis (p = 0.183, 95% confidence interval −14.4, 2.97) and a nonsignificant absolute difference in AHI of −5.43 events/h in the subgroup of patients who used nasal EPAP for ≥ 3 h (p = 0.314, 95% confidence interval −16.6, 5.76). Conclusions: This study suggests that EPAP is not an effective alternative to CPAP in acute stroke patients with OSA. Further work is needed to identify other more effective alternatives. Clinical Trial Registration: ClinicalTrials.gov, ID: NCT01703663 Citation: Wheeler NC, Wing JJ, O'Brien LM, Hughes R, Jacobs T, Claflin E, Chervin RD, Brown DL. Expiratory positive airway pressure for sleep apnea after stroke: a randomized, crossover trial. J Clin Sleep Med 2016;12(9):1233–1238. PMID:27306393

  16. Controlled trial of continuous positive airway pressure given by face mask for hyaline membrane disease.

    PubMed Central

    Allen, L P; Reynolds, E R; Rivers, R P; Le Souëf, P M; Wimberley, P D

    1977-01-01

    A controlled trial of elective intervention with continuous positive airway pressure (CPAP) was performed on 24 infants with hyaline membrane disease whose arterial oxygen tension (Pao2) fell below 8kPa (60 mmHg) while they were breathing a fractional inspired oxygen concentration (F1O2) greater than 0.60. A face mask was used to apply the CPAP. The progress of the 12 infants who were treated on entry to the trial was compared with that of 12 infants who were treated later. All 12 infants in the early-intervention group and 8 infants in the late-intervention group survived. When CPAP was started, Pao2 increased and the early-treated infants breathed high concentrations of oxygen for a shorter period than the late-treated infants. The 4 infants in the early-intervention group who required mechanical ventilation needed lower mean airway pressures to achieve satisfactory gas exchange than the 7 ventilated infants in the late-intervention group. We conclude that a Pao2 less than 8 kPa while breathing an F1o2 greater than 0.60 is an adequate indication for giving CPAP in hyaline membrane disease, and that early intervention with CPAP allows infants who go on to require mechanical ventilation to be ventilated at lower pressures. PMID:326199

  17. 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

  18. Computer simulations of pressure and velocity fields in a human upper airway during sneezing.

    PubMed

    Rahiminejad, Mohammad; Haghighi, Abdalrahman; Dastan, Alireza; Abouali, Omid; Farid, Mehrdad; Ahmadi, Goodarz

    2016-04-01

    In this paper, the airflow field including the velocity, pressure and turbulence intensity distributions during sneezing of a female subject was simulated using a computational fluid dynamics model of realistic upper airways including both oral and nasal cavities. The effects of variation of reaction of the subject during sneezing were also investigated. That is, the impacts of holding the nose or closing the mouth during sneezing on the pressure and velocity distributions were studied. Few works have studied the sneeze and therefore different aspects of this phenomenon have remained unknown. To cover more possibilities about the inlet condition of trachea in different sneeze scenarios, it was assumed that the suppressed sneeze happens with either the same inlet pressure or the same flow rate as the normal sneeze. The simulation results showed that during a normal sneeze, the pressure in the trachea reaches about 7000Pa, which is much higher than the pressure level of about 200Pa during the high activity exhalation. In addition, the results showed that, suppressing the sneeze by holding the nose or mouth leads to a noticeable increase in pressure difference in the tract. This increase was about 5 to 24 times of that during a normal sneeze. This significant rise in the pressure can justify some reported damage due to suppressing a sneeze.

  19. Unidirectional Expiratory Valve Method to Assess Maximal Inspiratory Pressure in Individuals without Artificial Airway

    PubMed Central

    Grams, Samantha Torres; Kimoto, Karen Yumi Mota; Azevedo, Elen Moda de Oliveira; Lança, Marina; de Albuquerque, André Luis Pereira; de Brito, Christina May Moran; Yamaguti, Wellington Pereira

    2015-01-01

    Introduction Maximal Inspiratory Pressure (MIP) is considered an effective method to estimate strength of inspiratory muscles, but still leads to false positive diagnosis. Although MIP assessment with unidirectional expiratory valve method has been used in patients undergoing mechanical ventilation, no previous studies investigated the application of this method in subjects without artificial airway. Objectives This study aimed to compare the MIP values assessed by standard method (MIPsta) and by unidirectional expiratory valve method (MIPuni) in subjects with spontaneous breathing without artificial airway. MIPuni reproducibility was also evaluated. Methods This was a crossover design study, and 31 subjects performed MIPsta and MIPuni in a random order. MIPsta measured MIP maintaining negative pressure for at least one second after forceful expiration. MIPuni evaluated MIP using a unidirectional expiratory valve attached to a face mask and was conducted by two evaluators (A and B) at two moments (Tests 1 and 2) to determine interobserver and intraobserver reproducibility of MIP values. Intraclass correlation coefficient (ICC[2,1]) was used to determine intraobserver and interobserver reproducibility. Results The mean values for MIPuni were 14.3% higher (-117.3 ± 24.8 cmH2O) than the mean values for MIPsta (-102.5 ± 23.9 cmH2O) (p<0.001). Interobserver reproducibility assessment showed very high correlation for Test 1 (ICC[2,1] = 0.91), and high correlation for Test 2 (ICC[2,1] = 0.88). The assessment of the intraobserver reproducibility showed high correlation for evaluator A (ICC[2,1] = 0.86) and evaluator B (ICC[2,1] = 0.77). Conclusions MIPuni presented higher values when compared with MIPsta and proved to be reproducible in subjects with spontaneous breathing without artificial airway. PMID:26360255

  20. Effects of Altered Intra-abdominal Pressure on the Upper Airway Collapsibility in a Porcine Model

    PubMed Central

    Ren, Shu-Lin; Li, Yan-Ru; Wu, Ji-Xiang; Ye, Jing-Ying; Jen, Rachel

    2015-01-01

    Background: Obstructive sleep apnea is strongly associated with obesity, particularly abdominal obesity common in centrally obese males. Previous studies have demonstrated that intra-abdominal pressure (IAP) is increased in morbid obesity, and tracheal traction forces may influence pharyngeal airway collapsibility. This study aimed to investigate that whether IAP plays a role in the mechanism of upper airway (UA) collapsibility via IAP-related caudal tracheal traction. Methods: An abdominal wall lifting (AWL) system and graded CO2 pneumoperitoneum pressure was applied to four supine, anesthetized Guizhou miniature pigs and its effects on tracheal displacement (TD) and airflow dynamics of UA were studied. Individual run data in 3 min obtained before and after AWL and obtained before and after graded pneumoperitoneum pressure were analyzed. Differences between baseline and AWL/graded pneumoperitoneum pressure data of each pig were examined using a Student's t-test or analysis of variance. Results: Application of AWL resulted in decreased IAP and significant caudal TD. The average displacement amplitude was 0.44 mm (P < 0.001). There were three subjects showed increased tidal volume (TV) (P < 0.01) and peak inspiratory airflow (P < 0.01); however, the change of flow limitation inspiratory UA resistance (Rua) was not significant. Experimental increased IAP by pneumoperitoneum resulted in significant cranial TD. The average displacement amplitude was 1.07 mm (P < 0.001) when IAP was 25 cmH2O compared to baseline. There were three subjects showed reduced Rua while the TV increased (P < 0.01). There was one subject had decreased TV and elevated Rua (P < 0.001). Conclusions: Decreased IAP significantly increased caudal TD, and elevated IAP significantly increased cranial TD. However, the mechanism of UA collapsibility appears primarily mediated by changes in lung volume rather than tracheal traction effect. TV plays an independent role in the mechanism of UA collapsibility

  1. Impact of adherence with positive airway pressure therapy on hypercapnia in obstructive sleep apnea

    PubMed Central

    Mokhlesi, Babak; Tulaimat, Aiman; Evans, Arthur T.; Wang, Yue; Itani, Abed-Alrahman; Hassaballa, Hesham A.; Herdegen, James J.; Stepanski, Edward J.

    2007-01-01

    Background Daytime hypercapnia associated with obstructive sleep apnea is common, particularly in the severely obese, and is associated with serious complications. Although positive airway pressure therapy improves daytime hypercapnia, the magnitude of benefit is unknown. Our objective was to quantify the effect of adherence with positive airway pressure on hypercapnia and hypoxia and to identify other factors that predict changes in PaCO2 and PaO2. Methods We performed a retrospective cohort study of seventy-five patients using a multivariable general linear model analysis to identify variables that predicted changes in PaCO2 and PaO2 after therapy. Bootstrap resampling methods were used to calculate confidence intervals for the effects of significant predictors and to internally validate the predictive models. Results The variables that predicted the change in PaCO2 were: average daily hours of positive pressure therapy, FEV1% of predicted, and baseline PaCO2 (model R2 = 0.70). The PaCO2 dropped 1.84 mm Hg per hour of adherence and plateaued at 7 hours of average daily use. PaO2 improved by approximately 3 mm Hg per hour of adherence and plateaued after 4.5 hours of therapy (model R2 = 0.48). Patients who used therapy for more than 4.5 hours per day experienced significant improvements in PaCO2 and PaO2 compared to less adherent patients (ΔPaCO2 7.7±5 vs. 2.4±4 mm Hg, p<0.001; ΔPaO2 9.2±11 vs. 1.8±9 mm Hg, p<0.001). For adherent patients, the need for daytime home oxygen therapy decreased from 30% to 6% (p=0.02). Conclusion In hypercapnic patients with obstructive sleep apnea, adherence with positive airway pressure is an important modifiable predictor of improvements in PaCO2 and PaO2, and its benefit plateaus between 5 to 7 hours of daily therapy. PMID:17557438

  2. Impact of Treatment with Continuous Positive Airway Pressure (CPAP) on Weight in Obstructive Sleep Apnea

    PubMed Central

    Quan, Stuart F.; Budhiraja, Rohit; Clarke, Denise P.; Goodwin, James L.; Gottlieb, Daniel J.; Nichols, Deborah A.; Simon, Richard D.; Smith, Terry W.; Walsh, James K.; Kushida, Clete A.

    2013-01-01

    Study Objective: To determine the impact of continuous positive airway pressure (CPAP) on weight change in persons with obstructive sleep apnea (OSA). Design, Setting, and Participants: The Apnea Positive Pressure Long-term Efficacy Study (APPLES) was a 6-month, randomized, double-blinded sham-controlled multicenter clinical trial conducted at 5 sites in the United States. Of 1,105 participants with an apnea hypopnea index ≥ 10 events/ hour initially randomized, 812 had body weight measured at baseline and after 6 months of study. Intervention: CPAP or Sham CPAP. Measurements: Body weight, height, hours of CPAP or Sham CPAP use, Epworth Sleepiness Scale score. Results: Participants randomized to CPAP gained 0.35 ± 5.01 kg, whereas those on Sham CPAP lost 0.70 ± 4.03 kg (mean ± SD, p = 0.001). Amount of weight gain with CPAP was related to hours of device adherence, with each hour per night of use predicting a 0.42 kg increase in weight. This association was not noted in the Sham CPAP group. CPAP participants who used their device ≥ 4 h per night on ≥ 70% of nights gained the most weight over 6 months in comparison to non-adherent CPAP participants (1.0 ± 5.3 vs. -0.3 ± 5.0 kg, p = 0.014). Conclusions: OSA patients using CPAP may gain a modest amount of weight with the greatest weight gain found in those most compliant with CPAP. Commentary: A commentary on this article appears in this issue on page 995. Citation: Quan SF; Budhiraja R; Clarke DP; Goodwin JL; Gottlieb DJ; Nichols DA; Simon RD; Smith TW; Walsh JK; Kushida CA. Impact of treatment with continuous positive airway pressure (CPAP) on weight in obstructive sleep apnea. J Clin Sleep Med 2013;9(10):989-993. PMID:24127141

  3. Predictors of Positive Airway Pressure Therapy Adherence in Children: A Prospective Study

    PubMed Central

    DiFeo, Natalie; Meltzer, Lisa J.; Beck, Suzanne E.; Karamessinis, Laurie R.; Cornaglia, Mary Anne; Traylor, Joel; Samuel, John; Gallagher, Paul R.; Radcliffe, Jerilynn; Beris, Heidi; Menello, Mary Kate; Marcus, Carole L.

    2012-01-01

    Study Objectives: Children with obstructive sleep apnea are increasingly being treated with positive airway pressure (PAP), particularly if they have underlying medical conditions. Although PAP is an effective treatment, its use is challenging due to poor adherence. We hypothesized that demographic, psychosocial, and polysomnographic parameters would be related to PAP adherence. We therefore prospectively collected data potentially pertaining to PAP adherence, and correlated it with PAP use. Methods: Fifty-six patients and their parents completed a series of psychosocial questionnaires prior to PAP initiation. Objective adherence data were obtained after 1 and 3 months of PAP use. Results: The population was primarily obese; 23% had neurodevelopmental disabilities. PAP adherence varied widely, with PAP being worn 22 ± 8 nights in month-1, but mean use was only 3 ± 3 h/night. The greatest predictor of use was maternal education (p = 0.002 for nights used; p = 0.033 for mean h used/night). Adherence was lower in African American children vs other races (p = 0.021). In the typically developing subgroup, adherence correlated inversely with age. Adherence did not correlate with severity of apnea, pressure levels, or psychosocial parameters other than a correlation between family social support and nights of PAP use in month-3. Conclusions: PAP adherence in children and adolescents is related primarily to family and demographic factors rather than severity of apnea or measures of psychosocial functioning. Further research is needed to determine the relative contributions of maternal education, socioeconomic status and cultural beliefs to PAP adherence in children, in order to develop better adherence programs. Citation: DiFeo N; Meltzer LJ; Beck SE; Karamessinis LR; Cornaglia MA; Traylor J; Samuel J; Gallagher PR; Radcliffe J; Beris H; Menello MK; Marcus CL. Predictors of positive airway pressure therapy adherence in children: a prospective study. J Clin Sleep Med 2012

  4. Effect of nasal continuous positive airway pressure during sleep on 24-hour blood pressure in obstructive sleep apnea.

    PubMed

    Wilcox, I; Grunstein, R R; Hedner, J A; Doyle, J; Collins, F L; Fletcher, P J; Kelly, D T; Sullivan, C E

    1993-09-01

    Ambulatory blood pressure (BP) was measured noninvasively (Oxford Medilog ABP) at 15-minute intervals for 24 hours before and after 8 weeks of treatment with nasal continuous positive airway pressure (nCPAP) in 19 men with obstructive sleep apnea (OSA). We included both normotensive and hypertensive patients, but hypertensives were studied after withdrawal of antihypertensive drugs. Ambulatory BP before and after treatment was compared using patients as their own controls. Treatment with nCPAP was successfully established in 14 of the 19 patients (74%). Blood pressure fell significantly in patients who were successfully treated: 24-hour mean BP (systolic/diastolic) decreased from 141 +/- 18/89 +/- 11 mm Hg to 134 +/- 19/85 +/- 13 mm Hg (p < 0.05). The reduction in 24-hour mean systolic BP occurred during both day and night, but a significant fall in mean diastolic BP was only observed during the day. The mean blood pressure fell in both normotensive and hypertensive patients. Patients who were inadequately treated with nCPAP had no reduction in mean 24-hour BP. Effective treatment of sleep apnea with nCPAP was associated with a significant fall in both systolic and diastolic BP independent of changes in body weight or alcohol consumption, suggesting that sleep apnea was an independent factor contributing to elevated nighttime and daytime BP in these patients.

  5. Evaluation of a humidified nasal high-flow oxygen system, using oxygraphy, capnography and measurement of upper airway pressures.

    PubMed

    Ritchie, J E; Williams, A B; Gerard, C; Hockey, H

    2011-11-01

    In this study, we evaluated the performance of a humidified nasal high-flow system (Optiflow, Fisher and Paykel Healthcare) by measuring delivered FiO, and airway pressures. Oxygraphy, capnography and measurement of airway pressures were performed through a hypopharyngeal catheter in healthy volunteers receiving Optiflow humidified nasal high flow therapy at rest and with exercise. The study was conducted in a non-clinical experimental setting. Ten healthy volunteers completed the study after giving informed written consent. Participants received a delivered oxygen fraction of 0.60 with gas flow rates of 10, 20, 30, 40 and 50 l/minute in random order FiO2, F(E)O2, F(E)CO2 and airway pressures were measured. Calculation of FiO2 from F(E)O2 and F(E)CO2 was later performed. Calculated FiO2 approached 0.60 as gas flow rates increased above 30 l/minute during nose breathing at rest. High peak inspiratory flow rates with exercise were associated with increased air entrainment. Hypopharyngeal pressure increased with increasing delivered gas flow rate. At 50 l/minute the system delivered a mean airway pressure of up to 7.1 cm H20. We believe that the high gas flow rates delivered by this system enable an accurate inspired oxygen fraction to be delivered. The positive mean airway pressure created by the high flow increases the efficacy of this system and may serve as a bridge to formal positive pressure systems.

  6. Efficacy of Home Single-Channel Nasal Pressure for Recommending Continuous Positive Airway Pressure Treatment in Sleep Apnea

    PubMed Central

    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.; Larrateguy, Luis D.; de Castro, Jorge Rey; Garcia-Ledesma, Estefania; Corral, Jaime; Martin-Vicente, Maria J.; Martinez-Null, Cristina; Egea, Carlos; Cancelo, Laura; García-Díaz, Emilio; Carmona-Bernal, Carmen; Sánchez-Armengol, Ángeles; Mayos, Merche; Miralda, Rosa M; Troncoso, Maria F.; Gonzalez, Monica; Martinez-Martinez, Marian; Cantalejo, Olga; Piérola, Javier; Vigil, Laura; Embid, Cristina; del Mar Centelles, Mireia; Prieto, Teresa Ramírez; Rojo, Blas; Lores, Vanesa

    2015-01-01

    Introduction: 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. Objectives: 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. Methods: 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. Results: 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. Conclusion: Automatic home single-channel nasal pressure 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. Clinical Trials Information: Clinicaltrial.gov identifier: NCT01347398. Citation: Masa JF, Duran-Cantolla J, Capote F, Cabello

  7. Graded exposure therapy for addressing claustrophobic reactions to continuous positive airway pressure: a case series report.

    PubMed

    Means, Melanie K; Edinger, Jack D

    2007-01-01

    Continuous positive airway pressure (CPAP) is a safe, effective treatment for obstructive sleep apnea, and yet many patients develop claustrophobic reactions to the CPAP nasal mask and cannot tolerate this treatment. We examined the efficacy of a graded in-vivo exposure therapy for enhancing CPAP adherence using a retrospective, case series design. Objective CPAP adherence data were obtained on clinical patients who attended 1 or more sessions of exposure therapy with a behavioral sleep psychologist. Compared to pre-treatment, patients used CPAP significantly longer after exposure therapy. No predictors of treatment response were identified. CPAP exposure therapy may be beneficial in some cases; however, further research is needed to determine types of patients most likely to benefit from this therapy.

  8. Commercial Motor Vehicle Driver Positive Airway Pressure Therapy Adherence in a Sleep Center

    PubMed Central

    Colvin, Loretta J.; Dace, Gayla A.; Colvin, Ryan M.; Ojile, Joseph; Collop, Nancy

    2016-01-01

    Study Objectives: To assess positive airway pressure (PAP) therapy adherence in commercial motor vehicle (CMV) drivers presenting to a sleep center. Methods: A retrospective chart review of 120 drivers evaluated for obstructive sleep apnea OSA and 53 initiated on PAP therapy in a single sleep center over a one-year period (2012); PAP therapy data were collected up to 1 year. Results: Early PAP usage best predicted adherence up to 1 year (p < 0.0001) compared to patient factors, OSA disease characteristics, and treatment elements analyzed. The proportion of participants adherent to therapy was 68.0% at 1 week, decreasing to 39.6% at 1 year, with 31.1% lost to follow-up by 1 year. In the group categorized based on adherence at week 1, 80.6% were adherent at 1 month, decreasing to 52.8% at 1 year. For the group non-adherent at 1 week, 29.4% were adherent at 1 month, decreasing to 11.7% at 1 year. Participants were predominantly male (75.8%), middle-aged (median 50.5 years), and African American (71.7%). Of those referred to the sleep center, 86.7% had OSA (median apnea-hypopnea index [AHI] or respiratory event index [REI] 20.1), with 51.0% of the OSA group having an AHI or REI > 20 and initiating PAP therapy. Conclusions: Early PAP utilization patterns predicted one year adherence for our CMV driver population within a sleep clinic setting. OSA testing of these CMV drivers after occupational health referral identifies high proportions of undiagnosed OSA, with approximately half requiring PAP therapy based on current published treatment recommendations. Citation: Colvin LJ, Dace GA, Colvin RM, Ojile J, Collop N. Commercial motor vehicle driver positive airway pressure therapy adherence in a sleep center. J Clin Sleep Med 2016;12(4):477–485. PMID:26715403

  9. Continuous positive airway pressure treatment for acute mountain sickness at 4240 m in the Nepal Himalaya.

    PubMed

    Johnson, Pamela L; Johnson, Claire C; Poudyal, Prasanta; Regmi, Nirajan; Walmsley, Megan A; Basnyat, Buddha

    2013-09-01

    Acute mountain sickness (AMS) is very common at altitudes above 2500 m. There are few treatment options in the field where electricity availability is limited, and medical assistance or oxygen is unavailable or difficult to access. Positive airway pressure has been used to treat AMS at 3800 m. We hypothesized that continuous positive airway pressure (CPAP) could be used under field conditions powered by small rechargeable batteries. Methods Part 1. 5 subjects trekked to 3500 m from 2800 m in one day and slept there for one night, ascending in the late afternoon to 3840 m, where they slept using CPAP 6-7 cm via mask. The next morning they descended to 3500 m, spent the day there, ascended in late afternoon to 3840 m, and slept the night without CPAP. Continuous overnight oximetry was recorded and the Lake Louise questionnaire for AMS administered both mornings. Methods Part 2. 14 trekkers with symptoms of AMS were recruited at 4240 m. All took acetazolamide. The Lake Louise questionnaire was administered, oximetry recorded, and CPAP 6-7 cm was applied for 10-15 min. CPAP was used overnight and oximetry recorded continuously. In the morning the Lake Louise questionnaire was administered, and oximetry recorded for 10-15 min. The equipment used in both parts was heated, humidified Respironics RemStar® machines powered by Novuscell™ rechargeable lithium ion batteries. Oximetry was recorded using Embletta™ PDS. Results Part 1. CPAP improved overnight Sao2 and eliminated AMS symptoms in the one subject who developed AMS. CPAP was used for 7-9 h and the machines operated for >8 h using the battery. Results Part 2. CPAP use improved Sao2 when used for 10-15 min at the time of recruitment and overnight CPAP use resulted in significantly reduced AMS symptoms. Conclusion. CPAP with rechargeable battery may be a useful treatment option for trekkers and climbers who develop AMS.

  10. Efficiency of cold passover and heated humidification under continuous positive airway pressure.

    PubMed

    Randerath, W J; Meier, J; Genger, H; Domanski, U; Rühle, K H

    2002-07-01

    Cold passover and heated humidifiers are employed for the prevention of side-effects associated with continuous positive airway pressure (CPAP) treatment. However, to date, it has not been possible to separately measure the humidity of inspired and expired air. The aim of this study was to compare the relative humidity of the inspired air and the water loss during respiration between cold passover and heated humidifiers under CPAP. Humidity and temperature were determined separately for the respiratory phases, without humidification, with cold passover and heated humidifiers in 10 healthy subjects. Humidity was measured with a capacitive hygrometer, temperature with a "Type K" thermosensor, and impedance of the total respiratory system with impulse oscillometry. The relative humidity (rH) of the inspired air (mean+/-SD) increased significantly from 24.0+/-9.1%, rH (34.8+/-1.0 degrees C, no humidifier) to 34.5+/-10.1%, rH (34.6+/-1.0 degrees C) under cold humidification, and to 53.9+/-13.2% rH (35.0+/-1.1 degrees C) under heated humidification. With heated humidification, water loss was reduced by 38% compared to cold humidification. The impedance increased from 5.7+/-1.8 cmH2O x L x s(-1) (no humidifier) to 6.7+/-1.8 cmH2O x L x s(-1) (heated humidifier). The authors conclude that the use of a heated humidifier during continuous positive airway pressure appreciably increases the relative humidity of the inspired air and reduces the water loss during respiration.

  11. 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

  12. Otic Barotrauma Resulting from Continuous Positive Airway Pressure: Case Report and Literature Review

    PubMed Central

    McCormick, Justin P.; Hildrew, Douglas M.; Lawlor, Claire M.; Guittard, Jesse A.; Worley, N. Knight

    2016-01-01

    Background: Obstructive sleep apnea (OSA) is a growing problem affecting millions of people in the United States. The prevalence of OSA has risen drastically in the past few decades concurrently with the increasing prevalence of obesity. Subsequently, there has been an ever-increasing rise in the use of continuous positive airway pressure (CPAP) devices. While using CPAP devices may lead to many adverse effects, the majority of these effects are described as relatively benign. Case Report: We describe the detailed clinical course and outcome for a patient with otic barotrauma as a result of excessive self-titration of CPAP therapy in an in-home setting. We also discuss the pathophysiology of otic barotrauma and present a review of current literature on the topic. Conclusion: While the benefits of CPAP are clear, we must take into account the rare but possible effects on ear structure and function. Many studies describe an increase in middle ear pressure with the use of CPAP, but few describe the effects of this increased pressure on the middle ear, such as the otic barotrauma described in this case. Given the increased prevalence of OSA, it is important to understand the risks associated with CPAP therapy. PMID:27303224

  13. A Respiratory Airway-Inspired Low-Pressure, Self-Regulating Valve for Drip Irrigation

    NASA Astrophysics Data System (ADS)

    Wang, Ruo-Qian; Winter, Amos G.; GEAR Lab Team

    2015-11-01

    One of the most significant barriers to achieving large-scale dissemination of drip irrigation is the cost of the pump and power system. An effective means of reducing power consumption is by reducing pumping pressure. The principle source of pressure drop in a drip system is the high flow resistance in the self-regulating flow resistors installed at the outlets of the pips, which evenly distribute water over a field. Traditional architectures require a minimum pressure of ~1 bar to maintain a constant flow rate; our aim is to reduce this pressure by 90% and correspondingly lower pumping power to facilitate the creation of low-cost, off-grid drip irrigation systems. This study presents a new Starling resistor architecture that enables the adjustment of flow rate with a fixed minimum pressure demand of ~0.1 bar. A Starling resistor is a flexible tube subjected to a transmural pressure, which collapses the tube to restrict flow. Our design uses a single pressure source to drive flow through the flexible tube and apply a transmural pressure. Flow into the flexible tube is restricted with a needle valve, to increase the transmural pressure. Using this device, a series of experiments were conducted with different flexible tube diameters, lengths and wall thickness. We found that the resistance of the needle valve changes flow rate but not the minimum transmural pressure required to collapse the tube. A lumped-parameter model was developed to capture the relationships between valve openings, pressure, and flow rates.

  14. Genioglossus reflex inhibition to upper-airway negative-pressure stimuli during wakefulness and sleep in healthy males

    PubMed Central

    Eckert, Danny J; McEvoy, R Doug; George, Kate E; Thomson, Kieron J; Catcheside, Peter G

    2007-01-01

    During wakefulness, obstructive sleep apnoea patients appear to compensate for an anatomically narrow upper airway by increasing upper airway dilator muscle activity, e.g. genioglossus, at least partly via a negative-pressure reflex that may be diminished in sleep. Previous studies have assessed the negative-pressure reflex using multi-unit, rectified, moving-time-average EMG recordings during brief pulses of negative upper-airway pressure. However, moving-time averaging probably obscures the true time-related reflex morphology, potentially masking transient excitatory and inhibitory components. This study aimed to re-examine the genioglossus negative-pressure reflex in detail, without moving-time averaging. Bipolar fine-wire electrodes were inserted per orally into the genioglossus muscle in 17 healthy subjects. Two upper airway pressure catheters were inserted per nasally. Genioglossus EMG reflex responses were generated via negative-pressure stimuli (∼−10 cmH2O at the choanae, 250 ms duration) delivered during wakefulness and sleep. Ensemble-averaged, rectified, genioglossus EMG recordings demonstrated reflex activation (onset latency 26 ± 1 ms; peak amplitude 231 ± 29% of baseline) followed by a previously unreported suppression (peak latency 71 ± 4 ms; 67 ± 8% of baseline). Single-motor-unit activity, clearly identifiable in ∼10% of trials in six subjects, showed a concomitant increase in the interspike interval from baseline (26 ± 9 ms, P = 0.01). Genioglossus negative-pressure reflex morphology and amplitude of the initial peak were maintained in non-rapid eye movement (NREM) sleep but suppression amplitude was more pronounced during NREM and declined further during REM sleep compared to wakefulness. These data indicate there are both excitatory and inhibitory components to the genioglossus negative-pressure reflex which are differentially affected by state. PMID:17395627

  15. Door Opening Affects Operating Room Pressure During Joint Arthroplasty.

    PubMed

    Mears, Simon C; Blanding, Renee; Belkoff, Stephen M

    2015-11-01

    Many resources are expended to ensure a sterile operating room environment. Efforts are made to prevent exposure of patients to personnel and to achieve positive room pressure to keep out airborne contaminants. Foot traffic into and out of the operating room during surgery can undermine these efforts. The authors investigated the number and duration of operating room door openings during hip and knee arthroplasty procedures and the effect of the door openings on room pressure. They tested the hypothesis that door openings defeat positive pressure, permitting air flow into the room. Room pressure and door status were monitored electronically during 191 hip and knee arthroplasty procedures. Operating room staff were unaware that data were being collected. The authors evaluated the data with regression analysis to determine whether the number and duration of door openings had an effect on room pressure. Significance was set at P<.05. Doors were open, on average, 9.5 minutes per case. In 77 of 191 cases, positive pressure was defeated, allowing air flow to reverse into the operating room. Total time with the door open significantly affected the minimum pressure recorded in the room (P<.02), but did not significantly affect average room pressure (P=.7). This finding suggested that the loss of positive pressure was a transient event from which the room recovered. The number and duration of door openings showed a significant association with length of surgery. Door openings threaten positive pressure, potentially jeopardizing operating room sterility. The causes of excessive operating room traffic must be evaluated to identify ways to reduce this traffic and the associated risks.

  16. The relationship between early reversibility test and maximal inspiratory pressure in patients with airway obstruction.

    PubMed

    Ozkaya, Sevket; Dirican, Adem; Kaya, Sule Ozbay; Karanfil, Rabia C; Bayrak, Merve G; Bostancı, Ozgür; Ece, Ferah

    2014-01-01

    Maximal inspiratory pressure (MIP) is a marker for assessing the degree of respiratory muscle dysfunction. Muscle dysfunction represents a pathophysiological feature of chronic obstructive pulmonary disease. We aimed to determinate the MIP value in patients with airway obstruction, to evaluate the change in MIP with bronchodilator drug, and to show the relationship between the changes in MIP and disease characteristics. We evaluated 21 patients with airway obstruction at the Department of Pulmonary Medicine, Samsun Medicalpark Hospital, Samsun, Turkey. We performed pulmonary function tests, measurement of MIP values, and reversibility tests with salbutamol. The baseline spirometry results were: mean forced vital capacity (FVC), 3,017±1,020 mL and 75.8%±20.8%; mean forced expiratory volume in 1 second (FEV1), 1,892±701 mL and 59.2%±18.2%; FEV1/FVC, 62.9%±5.5%; peak expiratory flow, 53%±19%. The pre-bronchodilator MIP value was 62.1±36.9 cmH2O. The reversibility test was found to be positive in 61.9% of patients with salbutamol. The absolute change and percentage of change in FEV1 were 318±223 mL and 19.8%±16.7%, respectively. The MIP value was increased by 5.5 cmH2O (8.8%) and was 67.7±30.3 cmH2O after bronchodilation. There was no significant relationship between age, FEV1, reversibility, and change in MIP with bronchodilator. However, the increase in MIP with bronchodilator drug was higher in patients with low body mass index (<25 kg/m(2)). We noted a 13.1% increase in FVC, a 19.8% increase in FEV1, a 20.2% increase in peak expiratory flow, and an 8.8% increase in MIP with salbutamol. In conclusion; MIP increases with bronchodilator therapy, regardless of changes in lung function, in patients with airway obstruction. The reversibilty test can be used to evaluate change in MIP with salbutamol.

  17. 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

  18. Alternative methods of titrating continuous positive airway pressure: a large multicenter study.

    PubMed

    Masa, Juan F; Jiménez, Antonio; Durán, Joaquín; Capote, Francisco; Monasterio, Carmen; Mayos, Mercedes; Terán, Joaquín; Hernández, Lourdes; Barbé, Ferrán; Maimó, Andrés; Rubio, Manuela; Montserrat, José M

    2004-12-01

    Standard practice for continuous positive airway pressure (CPAP) treatment in sleep apnea and hypopnea syndrome (SAHS) requires pressure titration during attended laboratory polysomnography. However, polysomnographic titration is expensive and time-consuming. The aim of this study was to ascertain, in a large sample of CPAP-naive patients, whether CPAP titration performed by an unattended domiciliary autoadjusted CPAP device or with a predicted formula was as effective as CPAP titration performed by full polysomnography. The main outcomes were the apnea-hypopnea index and the subjective daytime sleepiness. We included 360 patients with SAHS requiring CPAP treatment. Patients were randomly allocated into three groups: standard, autoadjusted, and predicted formula titration with domiciliary adjustment. The follow-up period was 12 weeks. With CPAP treatment, the improvement in subjective sleepiness and apnea-hypopnea index was very similar in the three groups. There were no differences in the objective compliance of CPAP treatment and in the dropout rate of the three groups at the end of the follow-up. Autoadjusted titration at home and predicted formula titration with domiciliary adjustment can replace standard titration. These procedures could lead to considerable savings in cost and to significant reductions in the waiting list.

  19. Effectiveness of applying continuous positive airway pressure in a patient with paradoxical vocal fold movement after endotracheal extubation: a case report

    PubMed Central

    Song, Keu La Me; Ko, Dong Chan; Pin, Jung Woo; Ryu, Kyong Ho; Kim, Hyun Soo

    2016-01-01

    Paradoxical vocal fold movement (PVFM) is an uncommon upper airway disorder defined as paradoxical adduction of the vocal folds during inspiration. The etiology and treatment of PVFM are unclear. The physician should manage this condition because of the possibility of near complete airway obstruction in severe case of PVFM. We report a case of successful airway management in a patient with PVFM by applying continuous positive airway pressure (CPAP). In this case, PVFM was detected after removing an endotracheal tube from a 67-year-old male who underwent excision of a laryngeal mass. The patient recovered without complications in 1 day with support by CPAP. PMID:26885309

  20. 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

  1. Overnight Motor Skill Learning Outcomes in Obstructive Sleep Apnea: Effect of Continuous Positive Airway Pressure

    PubMed Central

    Landry, Shane; O'Driscoll, Denise M.; Hamilton, Garun S.; Conduit, Russell

    2016-01-01

    Study Objective: To determine the effectiveness of continuous positive airway pressure (CPAP) therapy in alleviating known impairments in the overnight consolidation of motor skill learning in patients with obstructive sleep apnea (OSA). Methods: Twenty-five patients with untreated moderate-severe OSA, 13 first-night CPAP users, 17 compliant CPAP users, and 14 healthy control patients were trained on a motor sequence learning task (Sequential Finger Tapping Task, SFTT) and were subsequently tested prior to and after polysomnographic recorded sleep. Measures of subjective sleepiness (Karolinska Sleepiness Scale) and sustained attention (Psychomotor Vigilance Task) were also completed before and after sleep. Results: Typical analyses of overnight improvement on the SFTT show significantly greater overnight gains in motor task speed in controls (+11.6 ± 4.7%, p = 0.007) and compliant CPAP users (+8.9 ± 4.3%, p = 0.008) compared to patients with OSA (−4.86 ± 4.5%). Additional analyses suggest that these improvements in motor performance occurred prior to the sleep episode, as all groups significantly improved (15% to 22%) over a 10-min presleep rest period. Thereafter, performance in all groups significantly deteriorated over sleep (6% to 16%) with trends toward patients with OSA showing greater losses in performance compared to control patients and compliant CPAP users. No between-group differences in subjective sleepiness and sustained attention were found presleep and postsleep. Conclusions: The current data suggest impairments in overnight motor learning in patients with OSA may be a combination of deficient stabilization of memory over a sleep episode as well as increased vulnerability to time on task fatigue effects. Compliant CPAP usage possibly offsets both of these impediments to learning outcomes by improving both sleep quality and subsequent daytime function. Citation: Landry S, O'Driscoll DM, Hamilton GS, Conduit R. Overnight motor skill learning

  2. A New Animal Model of Obstructive Sleep Apnea Responding to Continuous Positive Airway Pressure

    PubMed Central

    Neuzeret, Pierre-Charles; Gormand, Frédéric; Reix, Philippe; Parrot, Sandrine; Sastre, Jean-Pierre; Buda, Colette; Guidon, Gérard; Sakai, Kazuya; Lin, Jian-Sheng

    2011-01-01

    Study Objectives: An improved animal model of obstructive sleep apnea (OSA) is needed for the development of effective pharmacotherapies. In humans, flexion of the neck and a supine position, two main pathogenic factors during human sleep, are associated with substantially greater OSA severity. We postulated that these two factors might generate OSA in animals. Design: We developed a restraining device for conditioning to investigate the effect of the combination of 2 body positions—prone (P) or supine (S)—and 2 head positions—with the neck flexed at right angles to the body (90°) or in extension in line with the body (180°)—during sleep in 6 cats. Polysomnography was performed twice on each cat in each of the 4 sleeping positions—P180, S180, P90, or S90. The effect of continuous positive airway pressure (CPAP) treatment was then investigated in 2 cats under the most pathogenic condition. Setting: NA. Patients or Participants: NA. Interventions: NA. Measurements and Results: Positions P180 and, S90 resulted, respectively, in the lowest and highest apnea-hypopnea index (AHI) (3 ± 1 vs 25 ± 2, P < 0.001), while P90 (18 ± 3, P < 0.001) and S180 (13 ± 5, P < 0.01) gave intermediate values. In position S90, an increase in slow wave sleep stage 1 (28% ± 3% vs 22% ± 3%, P < 0.05) and a decrease in REM sleep (10% ± 2% vs 18% ± 2%, P < 0.001) were also observed. CPAP resulted in a reduction in the AHI (8 ± 1 vs 27 ± 3, P < 0.01), with the added benefit of sleep consolidation. Conclusion: By mimicking human pathogenic sleep conditions, we have developed a new reversible animal model of OSA. Citation: Neuzeret PC; Gormand F; Reix P; Parrot S; Sastre JP; Buda C; Guidon G; Sakai K; Lin JS. A new animal model of obstructive sleep apnea responding to continuous positive airway pressure. SLEEP 2011;34(4):541-548. PMID:21461333

  3. Continuous Positive Airway Pressure and Breathlessness in Obese Patients with Obstructive Sleep Apnea: A Pilot Study

    PubMed Central

    Xiao, Sichang; Bastianpillai, Johan; Ratneswaran, Culadeeban; Pengo, Martino F.; Luo, Yuanming; Jolley, Caroline J.; Moxham, John; Steier, Joerg

    2016-01-01

    Study Objectives: Continuous positive airway pressure (CPAP) is an effective treatment for obstructive sleep apnea (OSA). However, long-term compliance with CPAP is limited. We tested the hypothesis that CPAP levels routinely used during sleep increase neural respiratory drive (NRD) and breathlessness, which may discourage compliance. Methods: This was an observational physiological cohort study in a respiratory physiology and sleep unit, University Hospital. Patients with a body mass index (BMI) > 25 kg/m2 and confirmed OSA were studied supine and awake on CPAP (4–20 cm H2O, increments of 2 cm H2O/3 min). We measured NRD during awake CPAP titration in obese subjects to quantify the response to the load of the respiratory system and compared it to the CPAP used for nocturnal treatment, with the modified Borg Scale (mBorg) for dyspnea recorded (from 0 to 10 points, with higher numbers indicating more breathlessness). Results: Fifteen patients (age 48 ± 10 years, 12 male, BMI 38.9 ± 5.8 kg/m2) with OSA (AHI 32.2 ± 21.1/h, 95th percentile of CPAP 14.1 ± 3.8 cm H2O) were studied and NRD (electromyogram of the parasternal intercostals, EMGpara; EMG of the external oblique, EMGabdomen) was recorded (awake, supine). Awake, EMGpara declined from baseline to 70.2% ± 17.1% when CPAP of 10.7 ± 3.4 cm H2O (P = 0.026) was applied. Further increase in CPAP led to a rise in EMGpara and increased breathlessness (P = 0.02). CPAP compliance (nights used) correlated negatively with mBorg scores (r = −0.738, P = 0.006). Conclusions: Awake, the respiratory system is maximally offloaded with lower than therapeutic CPAP levels in obese patients with OSA. Levels of NRD observed at effective CPAP levels while asleep are associated with breathlessness which may limit long-term CPAP compliance. Citation: Xiao S, Bastianpillai J, Ratneswaran C, Pengo MF, Luo Y, Jolley CJ, Moxham J, Steier J. Continuous positive airway pressure and breathlessness in obese patients with obstructive

  4. Expandable rubber plug seals openings for pressure testing

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Plug assembly seals openings in piping systems, vessels, and chambers for low pressure leak testing. The assembly, which consists of a rubber sealing plug and the mechanism for expanding it into a pressure-tight configuration, adequately seals irregular diameters without damage to mating surfaces.

  5. Spectral characteristics of airway opening and chest wall tidal flows in spontaneously breathing preterm infants.

    PubMed

    Habib, Robert H; Pyon, Kee H; Courtney, Sherry E; Aghai, Zubair H

    2003-05-01

    We compared the harmonic content of tidal flows measured simultaneously at the mouth and chest wall in spontaneously breathing very low birth weight infants (n = 16, 1,114 +/- 230 g, gestation age: 28 +/- 2 wk). Airway opening flows were measured via face mask-pneumotachograph (P-tach), whereas chest wall flows were derived from respiratory inductance plethysmography (RIP) excursions. Next, for each, we computed two spectral shape indexes: 1) harmonic distortion (k(d); k(d,P-tach) and k(d,RIP), respectively) defines the extent to which flows deviated from a single sine wave, and 2) the exponent of the power law (s; s(P-tach) and s(RIP), respectively), describing the spectral energy vs. frequency. P-tach and RIP flow spectra exhibited similar power law functional forms consistently in all infants. Also, mouth [s(P-tach) = 3.73 +/- 0.23% (95% confidence interval), k(d,P-tach) = 38.8 +/- 4.6%] and chest wall (s(RIP) = 3.51 +/- 0.30%, k(d,RIP) = 42.8 +/- 4.8%) indexes were similar and highly correlated (s(RIP) = 1.17 x s(P-tach) + 0.85; r(2) = 0.81; k(d,RIP) = 0.90 x k(d,P-tach) + 8.0; r(2) = 0.76). The corresponding time to peak tidal expiratory flow-to-expiratory time ratio (0.62 +/- 0.08) was higher than reported in older infants. The obtained s and k(d) values are similar to those reported in older and/or larger chronic lung disease infants, yet appreciably lower than for 1-mo-old healthy infants of closer age and/or size; this indicated increased complexity of tidal flows in very low birth weight babies. Importantly, we found equivalent flow spectral data from mouth and chest wall tidal flows. The latter are desirable because they avoid face mask artificial effects, including leaks around it, they do not interfere with ventilatory support delivery, and they may facilitate longer measurements that are useful in control of breathing assessment.

  6. The effect of continuous positive airway pressure on metabolic variables in patients with obstructive sleep apnoea.

    PubMed

    Schlatzer, Christian; Schwarz, Esther I; Kohler, Malcolm

    2014-02-01

    Obstructive sleep apnoea (OSA) is increasingly considered as a risk factor for metabolic disturbances, such as diabetes mellitus or dyslipidaemia. Continuous positive airway pressure (CPAP) therapy, the standard treatment for patients with OSA, may improve various metabolic variables, such as insulin sensitivity, glucose metabolism, lipids, fat distribution and adipokines. Several observational and uncontrolled clinical studies claim an improvement of these metabolic variables through the use of CPAP. However, there is only a limited number of clinical randomised controlled trials (RCTs) evaluating the effect of CPAP on metabolic variables. In this review, we summarise and discuss non-randomised studies and RCTs evaluating the effect of CPAP on metabolic variables in patients with OSA. In summary, the currently available body of evidence does not support a clinically important effect of CPAP treatment on any of the investigated metabolic variables. However, some investigators found small, but statistically significant changes in some metabolic variables, thus beneficial effects of CPAP treatment in selected patient cohorts cannot be excluded. To answer this question, more data from RCTs with well-defined study populations are warranted.

  7. Adherence to Continuous Positive Airway Pressure Treatment for Obstructive Sleep Apnea: Implications for Future Interventions

    PubMed Central

    Weaver, Terri E.; Sawyer, Amy M.

    2010-01-01

    Adherence to continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea (OSA) is a critical problem with adherence rates ranging from 30–60%. Poor adherence to CPAP is widely recognized as a significant limiting factor in treating OSA, reducing the overall effectiveness of the treatment and leaving many OSA patients at heightened risk for comorbid conditions, impaired function and quality of life. The extant literature examining adherence to CPAP provides critical insight to measuring adherence outcomes, defining optimal adherence levels, and predicting CPAP adherence. This research has revealed salient factors that are associated with or predict CPAP adherence and may guide the development of interventions to promote CPAP adherence. Over the past 10 years, intervention studies to promote CPAP adherence have incorporated a multitude of strategies including education, support, cognitive behavioral approaches, and mixed strategies. This review of the current state of science of CPAP adherence will (1) synthesize the extant literature with regard to measuring, defining, and predicting CPAP adherence, (2) review published intervention studies aimed at promoting CPAP adherence, and (3) suggest directions for future empiric study of adherence to CPAP that will have implications for translational science. Our current understanding of CPAP adherence suggests that adherence is a multi-factorial, complex clinical problem that requires similarly designed approaches to effectively address poor CPAP adherence in the OSA population. PMID:20308750

  8. 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.

  9. High Altitude, Continuous Positive Airway Pressure, and Obstructive Sleep Apnea: Subjective Observations and Objective Data

    PubMed Central

    Malhotra, Atul; Schwartz, Eli

    2013-01-01

    Abstract Ginosar, Yehuda, Atul Malhotra, and Eli Schwartz. High altitude, continuous positive airway pressure, and obstructive sleep apnea: Subjective observations and objective data. High Alt Med Biol 14:186–189, 2013.—We report observations made by one of the authors who ascended to the Thorang La pass (5416 m) in the Nepal Himalaya in October 2010, despite moderate-severe obstructive sleep apnea. We report the first recorded use of nasal CPAP to treat high altitude pulmonary edema (progressively severe dyspnea at rest and severe orthopnea, with tachycardia and tachypnea) that occurred at 4400 meters, when snow and darkness made safe evacuation difficult. We also present objective longitudinal data of the effects of altitude on auto-adjusting CPAP delivered via a portable nasal CPAP device, and on the apnea hypopnea index measured during sleep while using the device. OSA may be a risk factor for the development of high altitude pulmonary edema and we suggest that a nasal CPAP device located in high altitude trekking stations may provide an additional or alternative treatment option for managing high altitude pulmonary edema until evacuation is possible. PMID:23795742

  10. Dynamic airway pressure-time curve profile (Stress Index): a systematic review.

    PubMed

    Terragni, Pierpaolo; Bussone, Guido; Mascia, Luciana

    2016-01-01

    The assessment of respiratory mechanics at the bedside is necessary in order to identify the most protective ventilatory strategy. Indeed in the last 20 years, adverse effects of positive ventilation to the lung structures have led to a reappraisal of the objectives of mechanical ventilation. The ventilator setting requires repeated readjustment over the period of mechanical ventilation dependency and careful respiratory monitoring to minimize the risks, preventing further injury and permitting the lung and airways healing. Among the different methods that have been proposed and validated, the analysis of dynamic P-t curve (named Stress Index, SI) represents an adequate tool available at the bedside, repeatable and, therefore, able to identify the amount of overdistension occurring in the daily clinical practice, when modifying positive end-expiratory pressure. In this review we will analyze the evidence that supports respiratory mechanics assessment at the bedside and the application of the dynamic P/t curve profile (SI) to optimize protective ventilation in patients with acute respiratory failure.

  11. Effects of continuous positive airway pressure on energy balance regulation: a systematic review

    PubMed Central

    Shechter, Ari

    2016-01-01

    Obesity is both a cause and a possible consequence of obstructive sleep apnoea (OSA), as OSA seems to affect parameters involved in energy balance regulation, including food intake, hormonal regulation of hunger/satiety, energy metabolism and physical activity. It is known that weight loss improves OSA, yet it remains unclear why continuous positive airway pressure (CPAP) often results in weight gain. The goal of this systematic review is to explore if and how CPAP affects the behaviour and/or metabolism involved in regulating energy balance. CPAP appears to correct for a hormonal profile characterised by abnormally high leptin and ghrelin levels in OSA, by reducing the circulating levels of each. This is expected to reduce excess food intake. However, reliable measures of food intake are lacking, and not yet sufficient to make conclusions. Although studies are limited and inconsistent, CPAP may alter energy metabolism, with reports of reductions in resting metabolic rate or sleeping metabolic rate. CPAP appears to not have an appreciable effect on altering physical activity levels. More work is needed to characterise how CPAP affects energy balance regulation. It is clear that promoting CPAP in conjunction with other weight loss approaches should be used to encourage optimal outcomes in OSA patients. PMID:27824596

  12. Positive airway pressure improves nocturnal beat-to-beat blood pressure surges in obesity hypoventilation syndrome with obstructive sleep apnea.

    PubMed

    Carter, Jason R; Fonkoue, Ida T; Grimaldi, Daniela; Emami, Leila; Gozal, David; Sullivan, Colin E; Mokhlesi, Babak

    2016-04-01

    Positive airway pressure (PAP) treatment has been shown to have a modest effect on ambulatory blood pressure (BP) in patients with obstructive sleep apnea (OSA). However, there is a paucity of data on the effect of PAP therapy on rapid, yet significant, BP swings during sleep, particularly in obesity hypoventilation syndrome (OHS). The present study hypothesizes that PAP therapy will improve nocturnal BP on the first treatment night (titration PAP) in OHS patients with underlying OSA, and that these improvements will become more significant with 6 wk of PAP therapy. Seventeen adults (7 men, 10 women; age 50.4 ± 10.7 years, BMI 49.3 ± 2.4 kg/m(2)) with OHS and clinically diagnosed OSA participated in three overnight laboratory visits that included polysomnography and beat-to-beat BP monitoring via finger plethysmography. Six weeks of PAP therapy, but not titration PAP, lowered mean nocturnal BP. In contrast, when nocturnal beat-to-beat BPs were aggregated into bins consisting of at least three consecutive cardiac cycles with a >10 mmHg BP surge (i.e., Δ10-20, Δ20-30, Δ30-40, and Δ>40 mmHg), titration, and 6-wk PAP reduced the number of BP surges per hour (time × bin, P < 0.05). PAP adherence over the 6-wk period was significantly correlated to reductions in nocturnal systolic (r = 0.713, P = 0.001) and diastolic (r = 0.497, P = 0.043) BP surges. Despite these PAP-induced improvements in nocturnal beat-to-beat BP surges, 6 wk of PAP therapy did not alter daytime BP. In conclusion, PAP treatment reduces nocturnal beat-to-beat BP surges in OHS patients with underlying OSA, and this improvement in nocturnal BP regulation was greater in patients with higher PAP adherence.

  13. Gel pillow designed specifically for obstructive sleep apnea treatment with continuous positive airway pressure

    PubMed Central

    Salvaggio, Adriana; Lo Bue, Anna; Isidoro, Serena Iacono; Romano, Salvatore; Marrone, Oreste; Insalaco, Giuseppe

    2016-01-01

    ABSTRACT Objective: To determine whether the use of a gel pillow with side cutouts designed to accommodate a continuous positive airway pressure (CPAP) mask and reduce head temperature improves the efficacy of and adherence to auto-CPAP therapy. Methods: Twenty-three consecutive CPAP-naïve patients with obstructive sleep apnea were enrolled in the study. Patients were given an auto-CPAP machine with an appropriate CPAP mask and were instructed to use CPAP for 15 nights. They were instructed to sleep with their own pillow (the control pillow) from nights 1 to 5 and with either a foam pillow or a gel pillow, both of which had side cutouts, for 5 consecutive nights each, in random order. After night 15, auto-CPAP machine data were downloaded and patients rated their satisfaction with each pillow on a visual analog scale. Results: Twenty-two patients completed the protocol. The pressures administered, residual apnea-hypopnea index, air leaks, and mean duration of CPAP use did not differ among the periods during which each pillow was used. Patients were significantly more satisfied with the gel pillow than with the control pillow and the foam pillow (p = 0.022 and p = 0.004, respectively), their level of satisfaction with the gel pillow correlating significantly with excessive daytime sleepiness (r2 = 0.19; p = 0.0443). Conclusions: Among obstructive sleep apnea patients treated with nasal CPAP, the use of a gel pillow with side cutouts appears to have no impact on treatment effectiveness. Nevertheless, such patients seem to prefer a gel pillow over other types of pillows. PMID:27812636

  14. Physiological Correlation of Airway Pressure and Transpulmonary Pressure Stress Index on Respiratory Mechanics in Acute Respiratory Failure

    PubMed Central

    Pan, Chun; Chen, Lu; Zhang, Yun-Hang; Liu, Wei; Urbino, Rosario; Ranieri, V Marco; Qiu, Hai-Bo; Yang, Yi

    2016-01-01

    Background: Stress index at post-recruitment maneuvers could be a method of positive end-expiratory pressure (PEEP) titration in acute respiratory distress syndrome (ARDS) patients. However, airway pressure (Paw) stress index may not reflect lung mechanics in the patients with high chest wall elastance. This study was to evaluate the Paw stress index on lung mechanics and the correlation between Paw stress index and transpulmonary pressure (PL) stress index in acute respiratory failure (ARF) patients. Methods: Twenty-four ARF patients with mechanical ventilation (MV) were consecutively recruited from July 2011 to April 2013 in Zhongda Hospital, Nanjing, China and Ospedale S. Giovanni Battista-Molinette Hospital, Turin, Italy. All patients underwent MV with volume control (tidal volume 6 ml/kg) for 20 min. PEEP was set according to the ARDSnet study protocol. The patients were divided into two groups according to the chest wall elastance/respiratory system elastance ratio. The high elastance group (H group, n = 14) had a ratio ≥30%, and the low elastance group (L group, n = 10) had a ratio <30%. Respiratory elastance, gas-exchange, Paw stress index, and PL stress index were measured. Student's t-test, regression analysis, and Bland–Altman analysis were used for statistical analysis. Results: Pneumonia was the major cause of respiratory failure (71.0%). Compared with the L group, PEEP was lower in the H group (5.7 ± 1.7 cmH2O vs. 9.0 ± 2.3 cmH2O, P < 0.01). Compared with the H group, lung elastance was higher (20.0 ± 7.8 cmH2O/L vs. 11.6 ± 3.6 cmH2O/L, P < 0.01), and stress was higher in the L group (7.0 ± 1.9 vs. 4.9 ± 1.9, P = 0.02). A linear relationship was observed between the Paw stress index and the PL stress index in H group (R2= 0.56, P < 0.01) and L group (R2= 0.85, P < 0.01). Conclusion: In the ARF patients with MV, Paw stress index can substitute for PL to guide ventilator settings. Trial Registration: ClinicalTrials.gov NCT02196870 (https

  15. Continuous Positive Airway Pressure Improves Sleep and Daytime Sleepiness in Patients with Parkinson Disease and Sleep Apnea

    PubMed Central

    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

    Study Objectives: 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. Design: 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. Setting: Sleep laboratory. Participants: Thirty-eight patients with PD (mean age = 67.2 ± 9.2 y; 12 females). Intervention: Continuous positive airway pressure. Measurements: 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). Results: 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). Conclusions: Therapeutic continuous positive airway pressure versus placebo was effective in reducing apnea events, improving oxygen saturation, and deepening sleep in

  16. Established vascular effects of continuous positive airway pressure therapy in patients with obstructive sleep apnoea—an update

    PubMed Central

    Wons, Annette Marie

    2015-01-01

    The aim of this review was to summarize the current data from randomised controlled trials (RCTs) on vascular effects of continuous positive airway pressure (CPAP) therapy in patients with obstructive sleep apnoea (OSA). There is good evidence from RCTs that CPAP lowers blood pressure (BP) to a clinically significant amount. The effect seems to be dependent on the hours of nightly CPAP usage. Data from RCTs have also proven a beneficial effect of CPAP on measures of vascular function such as endothelial function and arterial stiffness. However, there is still a lack of evidence from RCTs proving that CPAP reduces vascular events and mortality. PMID:26101649

  17. Randomised controlled crossover trial of humidified continuous positive airway pressure in mild obstructive sleep apnoea

    PubMed Central

    Marshall, N; Neill, A; Campbell, A; Sheppard, D

    2005-01-01

    Background: It is unclear whether continuous positive airway pressure (CPAP), the treatment of choice for severe obstructive sleep apnoea (OSA), is effective at improving outcomes in mild OSA. Methods: To help define the role of humidified CPAP in mild OSA, a randomised crossover study was undertaken of patients with an apnoea hypopnoea index (AHI) of 5–30/hour. Subjective sleepiness, objective wakefulness, mood, reaction time, and quality of life were measured at baseline, after 3 weeks treatment with humidified CPAP and 3 weeks sham CPAP (2 week washout). Results: Twenty nine of 31 enrolled patients (age 25–67 years, seven women, mean (SD) body mass index 31.5 (6) kg/m2) completed the protocol. Humidified CPAP improved polysomnographic indices of OSA and Epworth Sleepiness Scale (2.4 points (95% CI 0.6 to 4.2)). Objective wakefulness (modified maintenance of wakefulness test) showed a trend towards improvement (5.2 minutes (95% CI –0.6 to 11)). Mood (Hospital Anxiety and Depression Scale), quality of life (SF 36, Functional Outcomes of Sleep Questionnaire), and reaction times (Psychomotor Vigilance Task) were not improved more than sham CPAP. Compliance with humidified and sham CPAP both averaged 4.9 hours/night. Placebo effects were evident in many outcomes and there was no clear treatment preference. Conclusions: Humidified CPAP improves subjective sleepiness and possibly objective wakefulness but not reaction times, quality of life, or mood. These results do not support the routine use of CPAP in all patients with mild OSA, but offers some support for the trialling of CPAP in those with severe sleepiness. PMID:15860720

  18. Impact of Patient Education on Compliance with Positive Airway Pressure Treatment in Obstructive Sleep Apnea.

    PubMed

    Saraç, Sema; Afşar, Gülgün Çetintaş; Oruç, Özlem; Topçuoğlu, Özgür Bilgin; Saltürk, Cüneyt; Peker, Yüksel

    2017-04-13

    BACKGROUND We addressed the impact of patient education followed by frequent visits on compliance with positive airway pressure (PAP) treatment in patients with obstructive sleep apnea (OSA) in a Turkish sleep clinic cohort. MATERIAL AND METHODS This single-center, randomized, controlled study was conducted in Istanbul, Turkey between June 2014 and April 2015. Among 115 eligible OSA patients (mean age 51.0±9.3 years; 75.5% men), 63 were randomized to standard support (SS) group (general information about OSA and PAP treatment at baseline), and 52 to educational support (ES) group (additional polysomnography chart viewing from both diagnostic and titration nights). All patients were scheduled to five PAP control visits between two weeks and six months after the PAP prescription. Primary outcome was the PAP compliance (4 hours/night for 70% of all the nights) at the last visit. RESULTS Average PAP usage was 4.2±2.5 hours/night in the SS group, and 5.2±2.1 hours/night in the ES group (p=0.027). PAP compliance was achieved among 68.3% in the SS group, and 86.5% in the ES group (p=0.021). In a multivariate analysis, ES strategy followed by frequent visits predicted PAP compliance (odds ratio [OR] 3.6, 95% confidence interval [CI] 1.2-10.6; p=0.020). Other predictors were obesity (OR 3.4, 95% CI 1.2-9.7; p=0.019) and severe OSA (apnea-hypopnea index ≥30/hour) at baseline (OR 4.7, 95% CI 1.2-17.6; p=0.023). Primary school education level was inversely related with PAP compliance (OR 0.3, 95% CI 0.1-0.9; p=0.036). CONCLUSIONS Patient education with polysomnography chart view followed by frequent visits increased long-term compliance with PAP treatment.

  19. Nasal Expiratory Positive Airway Pressure Devices (Provent) for OSA: A Systematic Review and Meta-Analysis

    PubMed Central

    Riaz, Muhammad; Certal, Victor; Nigam, Gaurav; Abdullatif, Jose; Zaghi, Soroush; Kushida, Clete A.; Camacho, Macario

    2015-01-01

    Objective. To quantify the effectiveness of nasal expiratory positive airway pressure (nasal EPAP) devices or Provent as treatment for obstructive sleep apnea (OSA). Methods. PubMed and six other databases were searched through November 15, 2015, without language limitations. Results. Eighteen studies (920 patients) were included. Pre- and post-nasal EPAP means ± standard deviations (M ± SD) for apnea-hypopnea index (AHI) in 345 patients decreased from 27.32 ± 22.24 to 12.78 ± 16.89 events/hr (relative reduction = 53.2%). Random effects modeling mean difference (MD) was −14.78 events/hr [95% CI −19.12, −10.45], p value < 0.00001. Oxygen desaturation index (ODI) in 247 patients decreased from 21.2 ± 19.3 to 12.4 ± 14.1 events/hr (relative reduction = 41.5%, p value < 0.00001). Lowest oxygen saturation (LSAT) M ± SD improved in 146 patients from 83.2 ± 6.8% to 86.2 ± 11.1%, MD 3 oxygen saturation points [95% CI 0.57, 5.63]. Epworth Sleepiness Scale (ESS) M ± SD improved (359 patients) from 9.9 ± 5.3 to 7.4 ± 5.0, MD −2.5 [95% CI −3.2, −1.8], p value < 0.0001. Conclusion. Nasal EPAP (Provent) reduced AHI by 53.2%, ODI by 41.5% and improved LSAT by 3 oxygen saturation points. Generally, there were no clear characteristics (demographic factors, medical history, and/or physical exam finding) that predicted favorable response to these devices. However, limited evidence suggests that high nasal resistance could be associated with treatment failure. Additional studies are needed to identify demographic and polysomnographic characteristics that would predict therapeutic success with nasal EPAP (Provent). PMID:26798519

  20. Effects of Use of a Continuous Positive Airway Pressure Device on Glaucoma

    PubMed Central

    Ulusoy, Seckin; Erden, Meltem; Dinc, Mehmet Emre; Yavuz, Nurdogan; Caglar, Erdem; Dalgic, Abdullah; Erdogan, Coskun

    2015-01-01

    Background The aim of this study was to investigate the prevalence of glaucoma in obstructive sleep apnea syndrome (OSAS) and to determine the efficacy of the equipment used in the treatment of this disease. Material/Methods In this cross-sectional study, 38 patients with OSAS used the continuous positive airway pressure (CPAP) device (Group 1) and 32 patients with OSAS refused CPAP device (Group 2). Thirty-six patients did not have OSAS (Group 3). Results Patient age, gender, height, weight, and neck circumference did not differ among groups (p>0.05); and the apnea-hypopnea index (AHI) and respiratory disturbance index (RDI) values did not differ between Groups 1 and 2 (p>0.05). Vision and pachymetric values did not differ among groups (p>0.05). The IOP was significantly higher in Group 2 than in Group 1 (p<0.05) but did not differ between Groups 1 and 3 (p>0.05). The fundus C/D ratio was significantly higher (p<0.05) in Group 2 than in the other groups but did not differ between Groups 1 and 3 (p>0.05). In Group 1, 2, and 3, 5.2%, 12.5%, and 0%, respectively, of patients had glaucoma. Conclusions OSAS should be considered a significant risk factor for glaucoma. Eye tests may help to identify individuals with undiagnosed OSAS, and such testing of patients with diagnosed OSAS may allow early detection of glaucoma and referral of such patients for CPAP therapy to prevent development of complications. PMID:26547930

  1. Effect of a heated humidifier during continuous positive airway pressure delivered by a helmet

    PubMed Central

    Chiumello, Davide; Chierichetti, Monica; Tallarini, Federica; Cozzi, Paola; Cressoni, Massimo; Polli, Federico; Colombo, Riccardo; Castelli, Antonio; Gattinoni, Luciano

    2008-01-01

    Introduction The helmet may be an effective interface for the delivery of noninvasive positive pressure ventilation. The high internal gas volume of the helmet can act as a 'mixing chamber', in which the humidity of the patient's expired alveolar gases increases the humidity of the dry medical gases, thus avoiding the need for active humidification. We evaluated the temperature and humidity of respiratory gases inside the helmet, with and without a heated humidifier, during continuous positive airway pressure (CPAP) delivered with a helmet. Methods Nine patients with acute respiratory failure (arterial oxygen tension/fractional inspired oxygen ratio 209 ± 52 mmHg) and 10 healthy individuals were subjected to CPAP. The CPAP was delivered either through a mechanical ventilator or by continuous low (40 l/min) or high flow (80 l/min). Humidity was measured inside the helmet using a capacitive hygrometer. The level of patient comfort was evaluated using a continuous scale. Results In patients with acute respiratory failure, the heated humidifier significantly increased the absolute humidity from 18.4 ± 5.5 mgH2O/l to 34.1 ± 2.8 mgH2O/l during ventilator CPAP, from 11.4 ± 4.8 mgH2O/l to 33.9 ± 1.9 mgH2O/l during continuous low-flow CPAP, and from 6.4 ± 1.8 mgH2O/l to 24.2 ± 5.4 mgH2O/l during continuous high-flow CPAP. Without the heated humidifier, the absolute humidity was significantly higher with ventilator CPAP than with continuous low-flow and high-flow CPAP. The level of comfort was similar for all the three modes of ventilation and with or without the heated humidifier. The findings in healthy individuals were similar to those in the patients with acute respiratory failure. Conclusion The fresh gas flowing through the helmet with continuous flow CPAP systems limited the possibility to increase the humidity. We suggest that a heated humidifier should be employed with continuous flow CPAP systems. PMID:18426561

  2. Continuous positive airway pressure for bronchiolitis in a general paediatric ward; a feasibility study

    PubMed Central

    2014-01-01

    Background Continuous positive airway pressure (CPAP) is commonly used to relieve respiratory distress in infants with bronchiolitis, but has mostly been studied in an intensive care setting. Our prime aim was to evaluate the feasibility of CPAP for infants with bronchiolitis in a general paediatric ward, and secondary to assess capillary PCO2 (cPCO2) levels before and during treatment. Methods From May 1st 2008 to April 30th 2012, infants with bronchiolitis at Stavanger University Hospital were treated with CPAP in a general paediatric ward, but could be referred to an intensive care unit (ICU) when needed, according to in-house guidelines. Levels of cPCO2 were prospectively registered before the start of CPAP and at approximately 4, 12, 24 and 48 hours of treatment as long as CPAP was given. We had a continuous updating program for the nurses and physicians caring for the infants with CPAP. The study was population based. Results 672 infants (3.4%) were hospitalized with bronchiolitis. CPAP was initiated in 53 infants (0.3%; 7.9% of infants with bronchiolitis), and was well tolerated in all but three infants. 46 infants were included in the study, the majority of these (n = 33) were treated in the general ward only. These infants had lower cPCO2 before treatment (8.0; 7.7, 8.6)(median; quartiles) than those treated at the ICU (n = 13) (9.3;8.5, 9.9) (p < 0.001). The level of cPCO2 was significantly reduced after 4 h in both groups; 1.1 kPa (paediatric ward) (p < 0.001) and 1.3 kPa (ICU) (p = 0.002). Two infants on the ICU did not respond to CPAP (increasing cPCO2 and severe apnoe) and were given mechanical ventilation, otherwise no side effects were observed in either group treated with CPAP. Conclusion Treatment with CPAP for infants with bronchiolitis may be feasible in a general paediatric ward, providing sufficient staffing and training, and the possibility of referral to an ICU when needed. PMID:24886569

  3. Cost-effectiveness of Out-of-Hospital Continuous Positive Airway Pressure for Acute Respiratory Failure

    PubMed Central

    Thokala, Praveen; Goodacre, Steve; Ward, Matt; Penn-Ashman, Jerry; Perkins, Gavin D.

    2015-01-01

    Study objective We determine the cost-effectiveness of out-of-hospital continuous positive airway pressure (CPAP) compared with standard care for adults presenting to emergency medical services with acute respiratory failure. Methods We developed an economic model using a United Kingdom health care system perspective to compare the costs and health outcomes of out-of-hospital CPAP to standard care (inhospital noninvasive ventilation) when applied to a hypothetical cohort of patients with acute respiratory failure. The model assigned each patient a probability of intubation or death, depending on the patient’s characteristics and whether he or she had out-of-hospital CPAP or standard care. The patients who survived accrued lifetime quality-adjusted life-years (QALYs) and health care costs according to their age and sex. Costs were accrued through intervention and hospital treatment costs, which depended on patient outcomes. All results were converted into US dollars, using the Organisation for Economic Co-operation and Development purchasing power parities rates. Results Out-of-hospital CPAP was more effective than standard care but was also more expensive, with an incremental cost-effectiveness ratio of £20,514 per QALY ($29,720/QALY) and a 49.5% probability of being cost-effective at the £20,000 per QALY ($29,000/QALY) threshold. The probability of out-of-hospital CPAP’s being cost-effective at the £20,000 per QALY ($29,000/QALY) threshold depended on the incidence of eligible patients and varied from 35.4% when a low estimate of incidence was used to 93.8% with a high estimate. Variation in the incidence of eligible patients also had a marked influence on the expected value of sample information for a future randomized trial. Conclusion The cost-effectiveness of out-of-hospital CPAP is uncertain. The incidence of patients eligible for out-of-hospital CPAP appears to be the key determinant of cost-effectiveness. PMID:25737210

  4. Upper airway dynamics during negative expiratory pressure in apneic and non-apneic awake snorers

    PubMed Central

    Ferretti, A; Giampiccolo, P; Redolfi, S; Mondini, S; Cirignotta, F; Cavalli, A; Tantucci, C

    2006-01-01

    Background The ability of negative expiratory pressure (NEP) technique to differentiate between awake snorers with and without obstructive sleep apnea-hypopnea (OSAH) was investigated. Methods Forty-eight subjects with sleep disordered breathing (SDB) and 7 healthy subjects, as non-snorer controls, underwent the NEP application of -5 and -7 cmH2O in the seated and supine position during wakefulness, after performing a sleep study. The upper airway collapsibility was assessed by computing the volume exhaled during the first 0.5 sec. (V,NEP0.5) and 1 sec. (V,NEP1) following the NEP start. Results Patients with severe (AHI ≥ 30) (n = 19) and mild-to-moderate (AHI <30 and >5) (n = 15) OSAH had lower V,NEP0.5 (340 ± 88 ml) as compared to snorers (AHI ≤ 5) (n = 14) (427 ± 101 ml; p < 0.01) and controls (n = 7) (492 ± 69 ml; p < 0.001) in the supine position with NEP -5 cmH2O. Less significant differences among the different groups were observed for V,NEP0.5 in the seated position with NEP -5 cmH2O and in both positions with NEP -7 cmH2O (only OSAH patients vs controls, p < 0.001). Similar results were obtained for V,NEP1 in either position by using both NEP -5 cmH2O and -7 cmH2O. In spite of this, a substantial overlapping of V,NEP0.5 and V,NEP1 between snorers and OSAH patients did not allow to identify a reliable diagnostic cut-off level. An inverse correlation with AHI was found for V,NEP0.5 in the supine position with NEP -5 cmH2O (rs = -0.46, p < 0.05) in severe OSAH patients. Conclusion The awake OSAH patients exhibit values of V,NEP0.5 and V,NEP1 lesser than those of awake snorers. The NEP technique, however, appears to have a limited usefulness as clinical tool for routine screening of the OSAH patients during wakefulness. PMID:16573817

  5. Positive Airway Pressure-Induced Conversion of Atrial Fibrillation to Normal Sinus Rhythm in Severe Obstructive Sleep Apnea

    PubMed Central

    Walia, Harneet K.; Chung, Mina K.; Ibrahim, Sally; Mehra, Reena

    2016-01-01

    Accumulating data implicate obstructive sleep apnea (OSA) as a predisposing factor to the development of atrial fibrillation (AF), the latter representing the most common sustained cardiac arrhythmia. The postulated mechanisms leading to atrial arrhythmogenesis in OSA include alterations in intrathoracic pressures, intermittent hypoxemia, and autonomic nervous system fluctuations. Although these OSA-related pathophysiologic pathways may result in atrial structural and electrical remodeling, thereby predisposing to AF, there are data to suggest that the immediate influences of respiratory events may trigger arrhythmic events. This case demonstrates an immediate reversal of AF to normal sinus rhythm with optimal continuous positive airway pressure (CPAP) therapy in the background of severe OSA. These findings of immediate benefit of reversal of OSA pathophysiology on cardiac arrhythmia suggest OSA may have acute influences on cardiac electrophysiology. Citation: Walia HK, Chung MK, Ibrahim S, Mehra R. Positive airway pressure-induced conversion of atrial fibrillation to normal sinus rhythm in severe obstructive sleep apnea. J Clin Sleep Med 2016;12(9):1301–1303. PMID:27166298

  6. 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

  7. High frequency jet ventilation and intermittent positive pressure ventilation. Effect of cerebral blood flow in patients after open heart surgery

    SciTech Connect

    Pittet, J.F.; Forster, A.; Suter, P.M. )

    1990-02-01

    Attenuation of ventilator-synchronous pressure fluctuations of intracranial pressure has been demonstrated during high frequency ventilation in animal and human studies, but the consequences of this effect on cerebral blood flow have not been investigated in man. We compared the effects of high frequency jet ventilation and intermittent positive pressure ventilation on CBF in 24 patients investigated three hours after completion of open-heart surgery. The patients were investigated during three consecutive periods with standard sedation (morphine, pancuronium): a. IPPV; b. HFJV; c. IPPV. Partial pressure of arterial CO{sub 2} (PaCO{sub 2}: 4.5-5.5 kPa) and rectal temperature (35.5 to 37.5{degree}C) were maintained constant during the study. The CBF was measured by intravenous {sup 133}Xe washout technique. The following variables were derived from the cerebral clearance of {sup 133}Xe: the rapid compartment flow, the initial slope index, ie, a combination of the rapid and the slow compartment flows, and the ratio of fast compartment flow over total CBF (FF). Compared to IPPV, HFJV applied to result in the same mean airway pressure did not produce any change in pulmonary gas exchange, mean systemic arterial pressure, and cardiac index. Similarly, CBF was not significantly altered by HFJV. However, important variations of CBF values were observed in three patients, although the classic main determinants of CBF (PaCO{sub 2}, cerebral perfusion pressure, Paw, temperature) remained unchanged. Our results suggest that in patients with normal systemic hemodynamics, the effects of HFJV and IPPV on CBF are comparable at identical levels of mean airway pressure.

  8. Effects of nasal continuous positive airway pressure and oxygen supplementation on norepinephrine kinetics and cardiovascular responses in obstructive sleep apnea.

    PubMed

    Mills, Paul J; Kennedy, Brian P; Loredo, Jose S; Dimsdale, Joel E; Ziegler, Michael G

    2006-01-01

    Obstructive sleep apnea (OSA) is characterized by noradrenergic activation. Nasal continuous positive airway pressure (CPAP) is the treatment of choice and has been shown to effectively reduce elevated norepinephrine (NE) levels. This study examined whether the reduction in NE after CPAP is due to an increase in NE clearance and/or a decrease of NE release rate. Fifty CPAP-naive OSA patients with an apnea-hypopnea index >15 were studied. NE clearance and release rates, circulating NE levels, urinary NE excretion, and blood pressure and heart rate were determined before and after 14 days of CPAP, placebo CPAP (CPAP administered at ineffective pressure), or oxygen supplementation. CPAP led to a significant increase in NE clearance (P < or = 0.01), as well as decreases in plasma NE levels (P < or = 0.018) and daytime (P < 0.001) and nighttime (P < 0.05) NE excretion. NE release rate was unchanged with treatment. Systolic (P < or = 0.013) and diastolic (P < or = 0.026) blood pressure and heart rate (P < or = 0.014) were decreased in response to CPAP but not in response to oxygen or placebo CPAP treatment. Posttreatment systolic blood pressure was best predicted by pretreatment systolic blood pressure and posttreatment NE clearance and release rate (P < 0.01). The findings indicate that one of the mechanisms through which CPAP reduces NE levels is through an increase in the clearance of NE from the circulation.

  9. Use of volume-targeted non-invasive bilevel positive airway pressure ventilation in a patient with amyotrophic lateral sclerosis*,**

    PubMed Central

    Diaz-Abad, Montserrat; Brown, John Edward

    2014-01-01

    Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease in which most patients die of respiratory failure. Although volume-targeted non-invasive bilevel positive airway pressure (BPAP) ventilation has been studied in patients with chronic respiratory failure of various etiologies, its use in ALS has not been reported. We present the case of a 66-year-old woman with ALS and respiratory failure treated with volume-targeted BPAP ventilation for 15 weeks. Weekly data downloads showed that disease progression was associated with increased respiratory muscle weakness, decreased spontaneous breathing, and increased use of non-invasive positive pressure ventilation, whereas tidal volume and minute ventilation remained relatively constant. PMID:25210968

  10. Dynamic Characteristics of Mechanical Ventilation System of Double Lungs with Bi-Level Positive Airway Pressure Model

    PubMed Central

    Shen, Dongkai; Zhang, Qian

    2016-01-01

    In recent studies on the dynamic characteristics of ventilation system, it was considered that human had only one lung, and the coupling effect of double lungs on the air flow can not be illustrated, which has been in regard to be vital to life support of patients. In this article, to illustrate coupling effect of double lungs on flow dynamics of mechanical ventilation system, a mathematical model of a mechanical ventilation system, which consists of double lungs and a bi-level positive airway pressure (BIPAP) controlled ventilator, was proposed. To verify the mathematical model, a prototype of BIPAP system with a double-lung simulators and a BIPAP ventilator was set up for experimental study. Lastly, the study on the influences of key parameters of BIPAP system on dynamic characteristics was carried out. The study can be referred to in the development of research on BIPAP ventilation treatment and real respiratory diagnostics. PMID:27660646

  11. Long-Term Effects of Continuous Positive Airway Pressure Treatment on Sexuality in Female Patients with Obstructive Sleep Apnea

    PubMed Central

    Petersen, Marian; Kristensen, Ellids; Berg, Søren; Midgren, Bengt

    2013-01-01

    Introduction Results from a previous study showed that sexuality was negatively affected in females with untreated obstructive sleep apnea (OSA). Data are sparse on the long-term effects of nocturnal continuous positive airway pressure (CPAP) treatment on sexual difficulties and sexual distress in female patients with OSA. Aim The aim of the present study was to investigate the effects after 1 year of CPAP treatment on sexual difficulties, sexual distress, and manifest sexual dysfunction in female patients with OSA. The effect of CPAP on life satisfaction was also investigated. Methods Fifty-four therapy-compliant, female patients (age 22–71) received a survey before and after 1 year of nocturnal CPAP treatment. The questions on this survey were drawn from three self-administered questionnaires: two on sexuality and one on life satisfaction. The results were compared with a population sample. The Epworth Sleepiness Scale was used for assessment of daytime sleepiness. Main Outcome Measures The Female Sexual Function Index, Female Sexual Distress Scale, Manifest Female Sexual Dysfunction, four questions from Life Satisfaction 11, and the Epworth Sleepiness Scale were all used to measure outcome. Results In total, 44 patients responded to the survey (81% response rate). The results were a significant, positive change in manifest female sexual dysfunction, but no significant changes in isolated sexual difficulties or sexual distress. Daytime sleepiness significantly decreased after 1 year. The results from the Life Satisfaction 11 questionnaire remained unchanged after 1 year. Conclusions After 1 year of CPAP treatment, female patients with OSA reported reduced manifest sexual dysfunction. However, it cannot be concluded if this result is due to CPAP treatment alone. Furthermore, reduced daytime tiredness was found in the surveyed population. CPAP treatment, per se, does not seem to affect partner relationships. Petersen M, Kristensen E, Berg S, and Midgren B. Long

  12. Mandibular Advancement Device as a Comparable Treatment to Nasal Continuous Positive Airway Pressure for Positional Obstructive Sleep Apnea

    PubMed Central

    Takaesu, Yoshikazu; Tsuiki, Satoru; Kobayashi, Mina; Komada, Yoko; Nakayama, Hideaki; Inoue, Yuichi

    2016-01-01

    Study Objectives: Positional obstructive sleep apnea (P-OSA) is a clinically common phenotype of OSA, which can be treated effectively with mandibular advancement devices (MADs). We hypothesized that the efficacy of an MAD is comparable to that of nasal continuous positive airway pressure (nCPAP) in P-OSA patients. Methods: Among patients diagnosed with OSA at a single sleep center from January 2008 to May 2014, male subjects with moderate OSA were recruited and stringently categorized as having P-OSA when the ratio of their lateral apnea-hypopnea index (AHI) to supine AHI was ≤ 0.5, their lateral sleep time was > 60 minutes, and their lateral REM sleep time was longer than 10 minutes. Treatment efficacy was compared between P-OSA subjects with an MAD (n = 34) and those with nCPAP (n = 34) after matching for age, body-mass index, and baseline AHI. Results: There were no significant differences in baseline AHI (MAD: nCPAP = 20.6 ± 3.9/h: 21.3 ± 1.7/h, p = 0.35) or in follow-up AHI (MAD: nCPAP = 4.7 ± 3.5/h: 3.4 ± 3.7/h, p = 0.12) between the 2 treatment groups, and hence MADs lowered the AHI to the same extent as nCPAP. Conclusions: These findings suggest that an MAD is as efficacious as nCPAP for P-OSA patients. MAD treatment for this specific phenotype may be a promising patient-tailored and first-line approach to OSA. Commentary: A commentary on this article appears in this issue on page 1079. Citation: Takaesu Y, Tsuiki S, Kobayashi M, Komada Y, Nakayama H, Inoue Y. Mandibular advancement device as a comparable treatment to nasal continuous positive airway pressure for positional obstructive sleep apnea. J Clin Sleep Med 2016;12(8):1113–1119. PMID:27250814

  13. The effect of obstructive sleep apnea and treatment with continuous positive airway pressure on stroke rehabilitation: rationale, design and methods of the TOROS study

    PubMed Central

    2014-01-01

    Background Obstructive sleep apnea is a common sleep disorder in stroke patients. Obstructive sleep apnea is associated with stroke severity and poor functional outcome. Continuous positive airway pressure seems to improve functional recovery in stroke rehabilitation. To date, the effect of continuous positive airway pressure on cognitive functioning in stroke patients is not well established. The current study will investigate the effectiveness of continuous positive airway pressure on both cognitive and functional outcomes in stroke patients with obstructive sleep apnea. Methods/Design A randomized controlled trial will be conducted on the neurorehabilitation unit of Heliomare, a rehabilitation center in the Netherlands. Seventy stroke patients with obstructive sleep apnea will be randomly allocated to an intervention or control group (n = 2×35). The intervention will consist of four weeks of continuous positive airway pressure treatment. Patients allocated to the control group will receive four weeks of treatment as usual. Outcomes will be assessed at baseline, immediately after the intervention and at two-month follow-up. In a supplementary study, these 70 patients with obstructive sleep apnea will be compared to 70 stroke patients without obstructive sleep apnea with respect to cognitive and functional status at rehabilitation admission. Additionally, the societal participation of both groups will be assessed at six months and one year after inclusion. Discussion This study will provide novel information on the effects of obstructive sleep apnea and its treatment with continuous positive airway pressure on rehabilitation outcomes after stroke. Trial registration Trial registration number: Dutch Trial Register NTR3412 PMID:24568360

  14. Health effects of obstructive sleep apnoea and the effectiveness of continuous positive airways pressure: a systematic review of the research evidence.

    PubMed Central

    Wright, J.; Johns, R.; Watt, I.; Melville, A.; Sheldon, T.

    1997-01-01

    OBJECTIVE: To examine the research evidence for the health consequences of obstructive sleep apnoea and the effectiveness of continuous positive airways pressure. DESIGN: A systematic review of published research, studies being identified by searching Medline (1966-96), Embase (1974-96), and CINAHL (Cumulative Index to Nursing and Allied Health Literature) (1982-95); scanning citations; and consulting experts. Studies in all languages were considered which either investigated the association between obstructive sleep apnoea in adults and key health outcomes or evaluated the effectiveness of treatment of obstructive sleep apnoea with continuous positive airways pressure in adults. MAIN OUTCOME MEASURES: Mortality, systematic hypertension, cardiac arrhythmias, ischaemic heart disease, left ventricular hypertrophy, pulmonary hypertension, stroke, vehicle accidents, measures of daytime sleepiness, and quality of life. RESULTS: 54 epidemiological studies examined the association between sleep apnoea and health related outcomes. Most were poorly designed and only weak or contradictory evidence was found of an association with cardiac arrhythmias, ischaemic heart disease, cardiac failure, systemic or pulmonary hypertension, and stroke. Evidence of a link with sleepiness and road traffic accidents was stronger but inconclusive. Only one small randomised controlled trial evaluated continuous positive airways pressure. Five non-randomised controlled trials and 38 uncontrolled trials were identified. Small changes in objectively measured daytime sleepiness were consistently found, but improvements in morbidity, mortality, and quality of life indicators were not adequately assessed. CONCLUSIONS: The relevance of sleep apnoea to public health has been exaggerated. The effectiveness of continuous positive airways pressure in improving health outcomes has been poorly evaluated. There is enough evidence suggesting benefit in reducing daytime sleepiness in some patients to warrant

  15. Retrospective, nonrandomized controlled study on autoadjusting, dual-pressure positive airway pressure therapy for a consecutive series of complex insomnia disorder patients

    PubMed Central

    Krakow, Barry; McIver, Natalia D; Ulibarri, Victor A; Nadorff, Michael R

    2017-01-01

    Purpose Emerging evidence shows that positive airway pressure (PAP) treatment of obstructive sleep apnea (OSA) and upper airway resistance syndrome (UARS) in chronic insomnia patients (proposed “complex insomnia” disorder) leads to substantial decreases in insomnia severity. Although continuous PAP (CPAP) is the pressure mode most widely researched, intolerance to fixed pressurized air is rarely investigated or described in comorbidity patients. This retrospective study examined dual pressure, autoadjusting PAP modes in chronic, complex insomnia disorder patients. Patients and methods Chronic insomnia disorder patients (mean [SD] insomnia severity index [ISI] =19.11 [3.34]) objectively diagnosed with OSA or UARS and using either autobilevel PAP device or adaptive servoventilation (ASV) device after failing CPAP therapy (frequently due to intolerance to pressurized air, poor outcomes, or emergence of CSA) were divided into PAP users (≥20 h/wk) and partial users (<20 h/wk) for comparison. Subjective and objective baseline and follow-up measures were analyzed. Results Of the 302 complex insomnia patients, PAP users (n=246) averaged 6.10 (1.78) nightly hours and 42.71 (12.48) weekly hours and partial users (n=56) averaged 1.67 (0.76) nightly hours and 11.70 (5.31) weekly hours. For mean (SD) decreases in total ISI scores, a significant (group × time) interaction was observed (F[1,300]=13.566; P<0.0001) with PAP users (–7.59 [5.92]; d=1.63) showing superior results to partial users (−4.34 [6.13]; d=0.81). Anecdotally, patients reported better tolerability with advanced PAP compared to previous experience with CPAP. Both adaptive servoventilation and autobilevel PAP showed similar ISI score improvement without statistical differences between devices. Total weekly hours of PAP use correlated inversely with change in insomnia symptoms (r=−0.256, P<0.01). Conclusion Insomnia severity significantly decreased in patients using autoadjusting PAP devices, but the

  16. Acute effects of nasal continuous positive airway pressure on 24-hour blood pressure and catecholamines in patients with obstructive sleep apnea.

    PubMed

    Minemura, H; Akashiba, T; Yamamoto, H; Akahoshi, T; Kosaka, N; Horie, T

    1998-12-01

    To assess the acute effects of nasal continuous positive airway pressure (CPAP) on the 24-hour blood pressure and the secretion of catecholamines in urine and plasma, we investigated the changes in the 24-hour blood pressure and urinary and plasma concentrations of epinephrine (E) and norepinephrine (NE) in 26 men with obstructive sleep apnea (OSA) with and without nasal CPAP. Nasal CPAP resulted in significant decreases in the daytime diastolic pressure (from 86 +/-16 mmHg to 83+/-12 mmHg), the nighttime diastolic pressure (from 81+/-12 mmHg to 77+/-9 mmHg) and the nighttime systolic pressures (from 125+/-15 mmHg to 120+/-10 mmHg). There was no significant difference between patients with and without CPAP in the daytime or nighttime urinary E level, but patients who received CPAP showed a significant decrease in daytime urinary NE level (from 156+/-112 microg/14h to 119+/-101 microg/14h) and nighttime urinary NE level (from 143+/-91 microg/10h to 112+/-65 microg/10h). The morning plasma level of NE also decreased (from 371+/-181 pg/ml to 273 +/-148 pg/ml) in patients who received nasal CPAP (p<0.02), but the plasma level of E remained unchanged. There were no correlations between PSG parameters and the reductions in blood pressure and the catecholamine levels induced by nasal CPAP. These findings suggest that OSA contributes, at least in part, to the development of systemic hypertension by increasing sympathetic nervous activity.

  17. End-inspiratory airway occlusion: a method to assess the pressure developed by inspiratory muscles in patients with acute lung injury undergoing pressure support.

    PubMed

    Foti, G; Cereda, M; Banfi, G; Pelosi, P; Fumagalli, R; Pesenti, A

    1997-10-01

    We evaluated the end-inspiratory occlusion maneuver as a means to estimate the inspiratory effort during pressure support ventilation (PS). In nine nonobstructed acute lung injury (ALI) patients, we applied four levels of PS (0, 5, 10, 15 cm H2O) to modify the inspiratory effort. End inspiratory occlusions (2 to 3 s) were performed at the end of each experimental period by pushing the inspiratory hold button of the ventilator (Servo 900 C; Siemens, Berlin, Germany). We took the difference between the end-inspiratory occlusion plateau pressure and the airway pressure before the occlusion (PEEP + PS) as an estimate of the inspiratory effort and called it PMI (Pmusc,index). From the esophageal pressure tracing we obtained a reference measurement of the pressure developed by the inspiratory muscles at end inspiration (Pmusc,ei) and of the pressure-time product per breath (PTP/b) and per minute (PTP/min). In each patient, PMI was correlated with Pmusc,ei (p < 0.01) and PTP/b (p < 0.01). A PMI threshold of 6 cm H2O detected PTP/min < 125 cm H2O s/min with a sensitivity of 0.89 and a specificity of 0.89. We conclude that PMI is a good estimate of the pressure developed by the inspiratory muscles in ALI patients and may be used to titrate PS level. The major advantage of PMI is that it can be obtained from the ventilator display without any additional equipment.

  18. Midfacial and Dental Changes Associated with Nasal Positive Airway Pressure in Children with Obstructive Sleep Apnea and Craniofacial Conditions

    PubMed Central

    Roberts, Soleil D.; Kapadia, Hitesh; Greenlee, Geoff; Chen, Maida L.

    2016-01-01

    Study Objectives: Nasal positive airway pressure (nPAP) for treatment of pediatric obstructive sleep apnea (OSA) is a widespread therapy that currently lacks longitudinal data describing how mask pressure impacts the developing facial skeleton. This retrospective cohort study compared midfacial growth in pediatric patients with underlying craniofacial conditions diagnosed with OSA who were compliant vs. noncompliant with nPAP therapy, and explored correlations between demographic, medical, and sleep variables with annual rate of facial change. Methods: Records from Seattle Children's Hospital's Craniofacial Center and Sleep Disorders Center were reviewed to identify patients prescribed nPAP for OSA with serial cephalographic images obtained during routine clinical care for concomitant craniofacial diagnosis. Lateral cephalometric analysis was used to determine mean annual change in midfacial structures from T1 (pre-nPAP) to T2 (post-nPAP) in compliant vs. noncompliant subjects. Compliance was indicated by nPAP usage of > 20 h/week for > 6 months. Results: 50 subjects were compliant with nPAP therapy (mean age 10.42 years) for an average of 2.57 years, and 50 subjects were noncompliant (mean age 8.53 years). Compliant subjects experienced negative mean annual change (retrusion) of the midface compared to forward growth seen in noncompliant subjects (SNA: −0.57° vs. 0.56°), counterclockwise rotation of palatal plane (SN-PP: −1.15° vs. 0.09°), and upper incisor flaring (U1-SN: 2.41° vs. −0.51°). Conclusions: Pressure to the midface from compliant nPAP use may alter normal facial growth. Cephalometric findings indicate a greater need for collaboration between sleep medicine physicians and orthodontists to monitor midfacial growth during nPAP treatment. Citation: Roberts SD, Kapadia H, Greenlee G, Chen ML. Midfacial and dental changes associated with nasal positive airway pressure in children with obstructive sleep apnea and craniofacial conditions. J Clin

  19. Effect of ethanol on the efficacy of nasal continuous positive airway pressure as a treatment for obstructive sleep apnea.

    PubMed

    Berry, R B; Desa, M M; Light, R W

    1991-02-01

    The effect of ethanol ingestion on the efficacy of nasal continuous positive airway pressure (nasal CPAP) as a treatment for the obstructive sleep apnea (OSA) syndrome was studied in ten obese male subjects undergoing this therapy. On the first night of polysomnography, the lowest level of CPAP that maintained airway patency was determined (critical level). On the second (control) night (C), subjects slept the entire night on this level of CPAP. On the third night (E), subjects ingested either 1.5 ml/kg (part A, N = 6) or 2.0 ml/kg (part B, N = 4) of 50 percent ethanol (100 proof vodka) over one half-hour starting 1 h before bedtime. A serum ethanol level was obtained at bedtime (part A: 63.7 +/- 17.3 mg/dl; part B: 108.6 +/- 20.6 mg/dl), and subjects were monitored on the critical level of CPAP. Comparison of nights C and E for parts A + B showed no difference in total sleep time (TST) or the amount of different sleep stages as an absolute time or a percentage of TST except that there was more stage 2 (as a percent of TST) on E nights. The apnea + hypopnea index and C and E nights did not differ and was quite low (3.6 +/- 3.7/h vs 1.9 +/- 2.7/h). Similarly, ethanol ingestion did not increase the number of desaturations to at or below 90 and 85 percent, or lower the mean arterial oxygen saturation in NREM or REM sleep. Analysis of parts A and B separately also showed no differences with respect to the apnea + hypopnea index or the number of desaturations on control and ethanol nights. We conclude that acute moderate ethanol ingestion does not decrease the efficacy of an optimum level of nasal CPAP.

  20. 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.

  1. 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

  2. Mechanical Properties of the Upper Airway

    PubMed Central

    Strohl, Kingman P.; Butler, James P.; Malhotra, Atul

    2013-01-01

    The importance of the upper airway (nose, pharynx, and larynx) in health and in the pathogenesis of sleep apnea, asthma, and other airway diseases, discussed elsewhere in the Comprehensive Physiology series, prompts this review of the biomechanical properties and functional aspects of the upper airway. There is a literature based on anatomic or structural descriptions in static circumstances, albeit studied in limited numbers of individuals in both health and disease. As for dynamic features, the literature is limited to studies of pressure and flow through all or parts of the upper airway and to the effects of muscle activation on such features; however, the links between structure and function through airway size, shape, and compliance remain a topic that is completely open for investigation, particularly through analyses using concepts of fluid and structural mechanics. Throughout are included both historically seminal references, as well as those serving as signposts or updated reviews. This article should be considered a resource for concepts needed for the application of biomechanical models of upper airway physiology, applicable to understanding the pathophysiology of disease and anticipated results of treatment interventions. PMID:23723026

  3. Nasal pillows as an alternative interface in patients with obstructive sleep apnoea syndrome initiating continuous positive airway pressure therapy.

    PubMed

    Ryan, Silke; Garvey, John F; Swan, Valerie; Behan, Renata; McNicholas, Walter T

    2011-06-01

    Side-effects directly due to the nasal mask are common in patients with obstructive sleep apnoea syndrome (OSAS) commencing continuous positive airway pressure (CPAP). Recently, nasal pillows have been designed to overcome these issues. Limited evidence exists of the benefits and effectiveness of these devices. Twenty-one patients (19 male, 49±10years) with the established diagnosis of OSAS [apnoea/hypopnoea index (AHI): 52±22] and who had a successful CPAP titration were commenced on CPAP therapy (10±2cmH2O), and randomized to 4weeks of a nasal pillow (P) and a standard nasal mask (M) in a crossover design. Outcome measures were objective compliance, AHI, quality of life, Epworth Sleepiness Score (ESS) and CPAP side-effects. There was no difference in compliance (M versus P: 5.1±1.9h versus 5.0±1.7h; P=0.701) and AHI (2.6±2.7 versus 3.0±2.9; P=0.509). Quality of life and ESS improved with CPAP, but there was no difference in the extent of improvement between both devices. Usage of nasal pillows resulted in less reported pressure on the face and more subjects found the nasal pillow the more comfortable device. However, there was no clear overall preference for either device at the end of the study (mask=57%, pillow=43%; P=0.513). The applied CPAP pressure did not correlate with compliance, AHI and ESS. Furthermore, no differences in outcome parameters were noted comparing groups with CPAP pressure <10 and ≥10cm H(2) O. Nasal pillows are equally effective in CPAP therapy, but do not generally lead to improved compliance.

  4. A real-world comparison of apnea-hypopnea indices of positive airway pressure device and polysomnography.

    PubMed

    Agrawal, Ritwick; Wang, Julie A; Ko, Anita G; Getsy, Joanne E

    2017-01-01

    The apnea hypopnea index (AHI) reported by positive airway pressure (PAP) device is widely used in clinical practice, yet its correlation with standardized AHI obtained during the sleep study is not established. The current study was conducted to investigate the correlation between AHI estimated by the PAP device and reported on the smart card with the AHI found during the PAP polysomnography (PSG) in the "real world" setting at an academic sleep center. We retrospectively reviewed the medical records of 280 patients who underwent a PAP titration PSG at Drexel sleep center, and were later prescribed a PAP device. The AHI was categorized in clinically relevant subgroups (as AHI ≤5 and AHI >5). The AHI at the final pressure on the PSG and the average AHI from the prescribed PAP device were compared. The results showed that in the majority (77.3%) of patients (126 of 163), the AHI from both PAP device and PSG correlated well and were in the same category (AHI ≤5 and AHI >5 respectively). The majority of patients (80.7%) with PSG AHI of <5 had PAP device AHI <5 as well. By contrast, if PSG AHI was >5, 61.5% patients reported good control, with AHI <5 on PAP device AHI. We conclude that in a majority of patients who were optimally titrated in the sleep laboratory, the PAP device continued to show optimal control at home.

  5. 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

  6. Intraoperative testing of opening and closing pressure predicts risk of low intraocular pressure after Ahmed glaucoma valve implantation

    PubMed Central

    Bochmann, F; Kipfer, A; Tarantino, J; Kaufmann, C; Bachmann, L; Thiel, M

    2014-01-01

    Purpose The aim of this study was to assess whether intraoperative testing of silicone Ahmed glaucoma valves (AGVs) would identify valves with an increased risk of low postoperative intraocular pressure (IOP). Methods In 30 consecutive cases of glaucoma surgery with AGV implantation, after priming the AGV, we intraoperatively measured the opening pressure A, closing pressure B, and re-opening pressure C using the active infusion pump of a phako-machine. IOP was checked postoperatively on the same day. Low IOP was defined as <5 mm Hg. Intraoperatively measured pressure characteristics of the valve function were analysed for their ability to predict postoperative IOP outcomes. Results Opening A, closing B, and re-opening C pressures (mean, (SD)) were 18.4 (5.1), 8.3 (4.7), and 11.7 (4.8)mm Hg, respectively. Ten patients (33.3%) had low IOP. An opening pressure of ≤18 mm Hg predicted low postoperative IOP with a sensitivity (10/10) of 100% (95% CI, 69.2–100) and a specificity (13/20) of 65.0% (95% CI, 40.8–84.6). Conclusions AGVs have a high variability of opening, closing, and re-opening pressures. An opening pressure of ≤18 mm Hg, a closing pressure of ≤10 mm Hg, or a re-opening pressure of ≤11 mm Hg identified all patients with low postoperative IOP. PMID:25060848

  7. 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

  8. Continuous positive airway pressure therapy in non-sleepy patients with obstructive sleep apnea: results of a meta-analysis

    PubMed Central

    Zhang, Dongmei; Luo, Jinmei; Qiao, Yixian

    2016-01-01

    Background Although continuous positive airway pressure (CPAP) has become the first line of therapy for obstructive sleep apnea (OSA), it remains controversial whether non-sleepy patients could benefit from CPAP treatment. Methods We searched the online databases Medline, Embase, the Cochrane library and the Cochrane Central Registry of Controlled Trials to select eligible control trials, including non-sleepy OSA patients and those patients treated by CPAP or either sham CPAP or no CPAP. Results Seven eligible studies (1,541 patients) were included. The pooled estimates of the mean changes after CPAP treatment for the systolic blood pressure (SBP) and diastolic blood pressure (DBP) were −0.51 mmHg (95% CI, −3.39 to 2.38 mmHg; P=0.73) and −0.92 mmHg (95% CI, −1.39 to −0.46 mmHg; P<0.001), respectively. CPAP should not improve subjective sleepiness in the minimally symptomatic OSA patients, as the change in the Epworth sleepiness scale (ESS) was −0.51 (95% CI, −1.68 to 0.67; P=0.397). However, CPAP can effectively reduce AHI or ODI by 15.57 events/h (95% CI, −29.32 to −1.82; P=0.026) compared to controls. However, the risk of cardiovascular events did not significantly decrease [odds ratio (OR), 0.80; 95% CI, 0.50 to 1.26; P=0.332] in the end. Conclusions CPAP treatment can reduce OSA severity in non-sleepy patients and minutely reduce the DBP, but CPAP seems to have no overall beneficial effects on subjective sleepiness, SBP, or cardiovascular risk. PMID:27867549

  9. Cystic fibrosis airway secretions exhibit mucin hyperconcentration and increased osmotic pressure.

    PubMed

    Henderson, Ashley G; Ehre, Camille; Button, Brian; Abdullah, Lubna H; Cai, Li-Heng; Leigh, Margaret W; DeMaria, Genevieve C; Matsui, Hiro; Donaldson, Scott H; Davis, C William; Sheehan, John K; Boucher, Richard C; Kesimer, Mehmet

    2014-07-01

    The pathogenesis of mucoinfective lung disease in cystic fibrosis (CF) patients likely involves poor mucus clearance. A recent model of mucus clearance predicts that mucus flow depends on the relative mucin concentration of the mucus layer compared with that of the periciliary layer; however, mucin concentrations have been difficult to measure in CF secretions. Here, we have shown that the concentration of mucin in CF sputum is low when measured by immunologically based techniques, and mass spectrometric analyses of CF mucins revealed mucin cleavage at antibody recognition sites. Using physical size exclusion chromatography/differential refractometry (SEC/dRI) techniques, we determined that mucin concentrations in CF secretions were higher than those in normal secretions. Measurements of partial osmotic pressures revealed that the partial osmotic pressure of CF sputum and the retained mucus in excised CF lungs were substantially greater than the partial osmotic pressure of normal secretions. Our data reveal that mucin concentration cannot be accurately measured immunologically in proteolytically active CF secretions; mucins are hyperconcentrated in CF secretions; and CF secretion osmotic pressures predict mucus layer-dependent osmotic compression of the periciliary liquid layer in CF lungs. Consequently, mucin hypersecretion likely produces mucus stasis, which contributes to key infectious and inflammatory components of CF lung disease.

  10. Effects of continuous positive airway pressure treatment on clinic and ambulatory blood pressures in patients with obstructive sleep apnea and resistant hypertension: a randomized controlled trial.

    PubMed

    Muxfeldt, Elizabeth S; Margallo, Victor; Costa, Leonardo M S; Guimarães, Gleison; Cavalcante, Aline H; Azevedo, João C M; de Souza, Fabio; Cardoso, Claudia R L; Salles, Gil F

    2015-04-01

    The effect of continuous positive airway pressure (CPAP) on blood pressures (BPs) in patients with resistant hypertension and obstructive sleep apnea is not established. We aimed to evaluate it in a randomized controlled clinical trial, with blinded assessment of outcomes. Four hundred thirty-four resistant hypertensive patients were screened and 117 patients with moderate/severe obstructive sleep apnea, defined by an apnea-hypopnea index ≥15 per hour, were randomized to 6-month CPAP treatment (57 patients) or no therapy (60 patients), while maintaining antihypertensive treatment. Clinic and 24-hour ambulatory BPs were obtained before and after 6-month treatment. Primary outcomes were changes in clinic and ambulatory BPs and in nocturnal BP fall patterns. Intention-to-treat and per-protocol (limited to those with uncontrolled ambulatory BPs) analyses were performed. Patients had mean (SD) 24-hour BP of 129(16)/75(12) mm Hg, and 59% had uncontrolled ambulatory BPs. Mean apnea-hypopnea index was 41 per hour and 58.5% had severe obstructive sleep apnea. On intention-to-treat analysis, there was no significant difference in any BP change, neither in nocturnal BP fall, between CPAP and control groups. The best effect of CPAP was on night-time systolic blood pressure in per-protocol analysis, with greater reduction of 4.7 mm Hg (95% confidence interval, -11.3 to +3.1 mm Hg; P=0.24) and an increase in nocturnal BP fall of 2.2% (95% confidence interval, -1.6% to +5.8%; P=0.25), in comparison with control group. In conclusion, CPAP treatment had no significant effect on clinic and ambulatory BPs in patients with resistant hypertension and moderate/severe obstructive sleep apnea, although a beneficial effect on night-time systolic blood pressure and on nocturnal BP fall might exist in patients with uncontrolled ambulatory BP levels.

  11. 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

  12. Polysomnographic predictors of persistent continuous positive airway pressure adherence in patients with moderate and severe obstructive sleep apnea.

    PubMed

    Chen, Yung-Fu; Hang, Liang-Wen; Huang, Chun-Sen; Liang, Shinn-Jye; Chung, Wei-Sheng

    2015-02-01

    Extensive use of continuous positive airway pressure (CPAP) has positive clinical benefits for most patients with obstructive sleep apnea (OSA). However, patient adherence is a major limiting factor to the effectiveness of CPAP treatment. This study determined the potential and quantifiable factors affecting the willingness of patients with OSA to undertake CPAP treatment by comparing the polysomnographic parameters recorded during diagnosis and titration. Patients with moderate and severe OSA who attended diagnostic polysomnography (PSG) and CPAP titration at the sleep center of China Medical University Hospital (CMUH) were included in the study. A total of 312 patients were divided into persistent users and nonusers of CPAP according to their use of in-home CPAP following titration and a 7-day CPAP trial. Multivariate logistic regression analyses were used to define the potential polysomnographic predictors of persistent CPAP adherence, and odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Most patients were men older than 50 years who were overweight or obese. Among the patients, 146 (46.8%) became persistent CPAP users. A 10% improvement of oxygen desaturation index (ODI) and a 10% increment in deep sleep percentage increased the chance of persistent CPAP use 1.18-fold and 1.07-fold, respectively. In addition, the improved ODI and deep sleep during CPAP titration increased the chance of persistent CPAP user. The polysomnographic parameters obtained from diagnosis and during titration can facilitate the prediction of persistent CPAP use.

  13. Sleep apnoea and the hypothalamic-pituitary-adrenal axis in men and women: effects of continuous positive airway pressure.

    PubMed

    Kritikou, Ilia; Basta, Maria; Vgontzas, Alexandros N; Pejovic, Slobodanka; Fernandez-Mendoza, Julio; Liao, Duanping; Bixler, Edward O; Gaines, Jordan; Chrousos, George P

    2016-02-01

    Previous findings on the association of obstructive sleep apnoea (OSA) and the hypothalamic-pituitary-adrenal (HPA) axis are inconsistent, partly due to the confounding effect of obesity and infrequent sampling. Our goal was to examine whether in a relatively nonobese population, OSA is associated with elevated cortisol levels and to assess the effects of a 2-month placebo-controlled continuous positive airway pressure (sham-CPAP) use.72 subjects (35 middle-aged males and post-menopausal females with OSA, and 37 male and female controls) were studied in the sleep laboratory for four nights. 24-h blood sampling was performed every hour on the fourth day and night in the sleep laboratory at baseline, after sham-CPAP and after CPAP treatment.In both apnoeic men and women, OSA was associated with significantly higher 24-h cortisol levels compared with controls, whereas CPAP lowered cortisol levels significantly, close to those of controls.These results suggest that OSA in nonobese men and slightly obese women is associated with HPA axis activation, similar albeit stronger compared with obese individuals with sleep apnoea. Short-term CPAP use decreased cortisol levels significantly compared with baseline, indicating that CPAP may have a protective effect against comorbidities frequently associated with chronic activation of the HPA axis, e.g. hypertension.

  14. Default network response to a working memory challenge after withdrawal of continuous positive airway pressure treatment for obstructive sleep apnea.

    PubMed

    Sweet, Lawrence H; Jerskey, Beth A; Aloia, Mark S

    2010-06-01

    Lower working memory performance and altered brain activity have been reported in studies of obstructive sleep apnea (OSA) patients. However, little is known about the effect of treatment of OSA on brain function, particularly effects on default network processing. We previously reported increased brain response to a working memory challenge in active regions and decreased response in relatively deactivated a priori regions of interest (ROIs) following withdrawal of continuous positive airway pressure (CPAP) treatment. This follow-up analysis was conducted to examine the effects of CPAP withdrawal on default network processing using empirically defined ROIs analyses (i.e., in ROIs exhibiting significant deactivation in the sample). Ten OSA patients performed a 2-Back working memory task during functional magnetic resonance imaging in two separate conditions, following regular CPAP use, and after two nights of CPAP withdrawal. Eleven clusters of significant 2-Back-related deactivation consistent with the default network were identified and further examined for CPAP withdrawal effects. Significant further deactivation relative to the treatment adherent baseline was observed in the majority of these ROIs during the withdrawal condition. The magnitude of deactivation during withdrawal was significantly associated with better working memory performance in the posterior cingulate and right postcentral gyrus, and greater sleepiness in the left and right medial frontal gyrus. Results suggest that default network functions are further suspended as a result of a shifting of attention towards a more difficult active task in the context of lowered attentional capacity related to sleepiness.

  15. Application of positive airway pressure in restoring pulmonary function and thoracic mobility in the postoperative period of bariatric surgery: a randomized clinical trial

    PubMed Central

    Brigatto, Patrícia; Carbinatto, Jéssica C.; Costa, Carolina M.; Montebelo, Maria I. L.; Rasera-Júnior, Irineu; Pazzianotto-Forti, Eli M.

    2014-01-01

    Objective: To evaluate whether the application of bilevel positive airway pressure in the postoperative period of bariatric surgery might be more effective in restoring lung volume and capacity and thoracic mobility than the separate application of expiratory and inspiratory positive pressure. Method: Sixty morbidly obese adult subjects who were hospitalized for bariatric surgery and met the predefined inclusion criteria were evaluated. The pulmonary function and thoracic mobility were preoperatively assessed by spirometry and cirtometry and reevaluated on the 1st postoperative day. After preoperative evaluation, the subjects were randomized and allocated into groups: EPAP Group (n=20), IPPB Group (n=20) and BIPAP Group (n=20), then received the corresponding intervention: positive expiratory pressure (EPAP), inspiratory positive pressure breathing (IPPB) or bilevel inspiratory positive airway pressure (BIPAP), in 6 sets of 15 breaths or 30 minutes twice a day in the immediate postoperative period and on the 1st postoperative day, in addition to conventional physical therapy. Results: There was a significant postoperative reduction in spirometric variables (p<0.05), regardless of the technique used, with no significant difference among the techniques (p>0.05). Thoracic mobility was preserved only in group BIPAP (p>0.05), but no significant difference was found in the comparison among groups (p>0.05). Conclusion: The application of positive pressure does not seem to be effective in restoring lung function after bariatric surgery, but the use of bilevel positive pressure can preserve thoracic mobility, although this technique was not superior to the other techniques. PMID:25590448

  16. 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

  17. Pharyngeal airway space and frontal and sphenoid sinus changes after maxillomandibular advancement with counterclockwise rotation for class II anterior open bite malocclusions

    PubMed Central

    Prado, FB; Rossi, AC; Freire, AR; Groppo, FC; De Moraes, M; Caria, PHF

    2012-01-01

    Objectives The purpose of this study was to cephalometrically evaluate the pharyngeal airway space and frontal and sphenoid sinus changes after maxillomandibular advancement counterclockwise rotation for class II anterior open bite malocclusion. Methods The study included 49 patients (98 lateral teleradiographs; 36 females and 13 males) who were analysed in the pre-operative (1 week before surgery) and post-operative (6 months after surgery) periods. In each lateral teleradiography, the dimensions of the inferior and superior pharyngeal airway space, TB-PhW1 [the point between the posterior aspect of the tongue to the dorsal pharyngeal wall (oropharynx) (TB) and the point on the dorsal pharyngeal wall closest to TB (PhW1)] and UP-PhW2 [and the point between the posterior aspect of the soft palate to the dorsal pharyngeal wall (nasopharynx) (UP) (PhW2)] measurements were evaluated, as well as the dimensions of the frontal and sphenoid sinuses. The differences between the two operative times were evaluated by Student's t-test. Results All measurements showed excellent reproducibility for the intraclass correlation coefficient (ICC > 0.9; p < 0.0001). There was an increase in the measurements TB-PhW1 and UP-PhW2 and a decrease in the dimensions of the frontal and sphenoid sinuses after orthognathic surgery. Conclusions The morphology of the superior and inferior pharyngeal airway space and frontal and sphenoid sinuses changes after 6 months of maxillomandibular advancement counterclockwise rotation for class II anterior open bite malocclusion. PMID:22116128

  18. Predictors of Long-Term Adherence to Continuous Positive Airway Pressure Therapy in Patients with Obstructive Sleep Apnea and Cardiovascular Disease in the SAVE Study

    PubMed Central

    Chai-Coetzer, Ching Li; Luo, Yuan-Ming; Antic, Nick A.; Zhang, Xi-Long; Chen, Bao-Yuan; He, Quan-Ying; Heeley, Emma; Huang, Shao-Guang; Anderson, Craig; Zhong, Nan-Shan; McEvoy, R. Doug

    2013-01-01

    Study Objectives: To determine the clinical variables that best predict long- term continuous positive airway pressure (CPAP) adherence among patients with cardiovascular disease who have obstructive sleep apnea (OSA). Design: 12-mo prospective within-trial observational study. Setting: Centers in China, Australia, and New Zealand participating in the Sleep Apnea cardioVascular Endpoints (SAVE) study. Patients: There were 275 patients age 45-70 y with cardiovascular disease (i.e., previously documented transient ischemic attack, stroke, or coronary artery disease) and OSA (4% oxygen desaturation index (ODI) > 12) who were randomized into the CPAP arm of the SAVE trial prior to July 1, 2010. Methods: Age, sex, country of residence, type of cardiovascular disease, baseline ODI, severity of sleepiness, and Hospital Anxiety and Depression Scale (HADS) scores plus CPAP side effects and adherence at 1 mo were entered in univariate analyses in an attempt to identify factors predictive of CPAP adherence at 12 mo. Variables with P < 0.2 were then included in a multivariate analysis using a linear mixed model with sites as a random effect and 12-mo CPAP use as the dependent outcome variable. Measurements and Results: CPAP adherence at 1, 6, and 12 mo was (mean ± standard deviation) 4.4 ± 2.0, 3.8 ± 2.3, and 3.3 ± 2.4 h/night, respectively. CPAP use at 1 mo (effect estimate ± standard error, 0.65 ± 0.07 per h increase, P < 0.001) and side effects at 1 mo (-0.24 ± 0.092 per additional side effect, P = 0.009) were the only independent predictors of 12- mo CPAP adherence. Conclusion: Continuous positive airway pressure use in patients with coexisting cardiovascular disease and moderate to severe obstructive sleep apnea decreases significantly over 12 months. This decline can be predicted by early patient experiences with continuous positive airway pressure (i.e., adherence and side effects at 1 month), raising the possibility that intensive early interventions could

  19. Sleep-related breathing disorders. 5. Nasal continuous positive airway pressure treatment for obstructive sleep apnoea.

    PubMed

    Grunstein, R R

    1995-10-01

    CPAP should be considered the first line of treatment in patients with moderate to severe obstructive sleep apnoea. In our centre in Sydney this generally means patients with more than 20 apnoea/hypopnoeas per hour with repeated dips in oxyhaemoglobin saturation and usually some symptomatology. Despite this first line role of nasal CPAP, recent objective studies question whether earlier enthusiastic reports on adherence to CPAP are correct. The role of technical innovations in new CPAP machines in improving usage remains to be tested. The "drop out" rate from physician selection for a CPAP trial to highly compliant user is certainly more than 50% of patients. What happens to these patients? Data from some studies suggest that surgical treatments are used, at least in the USA, but in all probability many of these patients remain untreated. The challenge in the next decade is either to improve CPAP devices to increase usage in this group or to develop other treatment options. The role of intensive inhospital "acclimatisation" to CPAP also has yet to be objectively tested. It is unclear whether "intelligent" CPAP will make huge inroads in increasing the number of patients who accept CPAP trials, prescriptions, or compliance. It will have minimal impact on patients with mask problems or claustrophobia or those who feel that CPAP is inconvenient. There is a high likelihood that it will reduce technologist workload during CPAP titration studies. "Intelligent" CPAP may help to reduce total overnight mouth leakage and therefore reduce nasal side effects. The current expense of developing such devices will mean that they are unlikely to supersede much cheaper standard "one pressure" CPAP machines in the next few years.

  20. WHICH AIRWAY PRESSURE SHOULD BE APPLIED DURING BREATH-HOLD IN DOGS UNDERGOING THORACIC COMPUTED TOMOGRAPHY?

    PubMed

    Guarracino, Alessandro; Lacitignola, Luca; Auriemma, Edoardo; De Monte, Valentina; Grasso, Salvatore; Crovace, Antonio; Staffieri, Francesco

    2016-09-01

    This randomized controlled trial study aimed to identify the optimal positive pressure (PP) level that can clear atelectasis while avoiding pulmonary hyperinflation during the breath-hold technique in dogs undergoing thoracic computed tomography (CT). Sixty dogs affected by mammary tumors undergoing thoracic CT for the screening of pulmonary metastases were randomly assigned to six groups with different levels of PP during the breath-hold technique: 0 (control), 5 (PP5), 8 (PP8), 10 (PP10), 12 (PP12), and 15 (PP15) cmH2 O. The percentage of atelectatic lung region was lower in the PP10 (3.7 ± 1.1%; P = 0.002), PP12 (3.4 ± 1.3%; P = 0.0001), and PP15 (2.8 ± 0.9%; P = 0.006) groups than in the control group (5.0 ± 2.3%), and the percentage of poorly aerated lung region was lower in the PP8 (15.1 ± 2.6%; P = 0.0009), PP10 (13.0 ± 2.0 %; P = 0.002), PP12 (13.0 ± 2.2 %; P = 0.0002), and PP15 (11.1 ± 1.9%; P = 0.0002) groups than in the control group (19.8 ± 5.0). The percentage of normally aerated lung region, however, was higher in the PP10 (79.7 ± 4.1%; P = 0.005), PP12 (79.8 ± 5.1%; P = 0.0002), and PP15 (80.2 ± 4.9%; P = 0.002) groups than in the control group (73.4 ± 6.6%). A PP of 10-12 cmH2 O during the breath-hold technique should be considered to improve lung aeration during a breath-hold technique in dogs undergoing thoracic CT.

  1. A randomised control study comparing the Infant Flow Driver with nasal continuous positive airway pressure in preterm infants

    PubMed Central

    Mazzella, M; Bellini, C; Calevo, M; Campone, F; Massocco, D; Mezzano, P; Zullino, E; Scopesi, F; Arioni, C; Bonacci, W; Serra, G

    2001-01-01

    OBJECTIVE—To compare the effectiveness of the Infant Flow Driver (IFD) with single prong nasal continuous positive airway pressure (nCPAP) in preterm neonates affected by respiratory distress syndrome.
DESIGN—Randomised controlled study.
PATIENTS—Between September 1997 and March 1999, 36 preterm infants who were eligible for CPAP treatment were randomly selected for either nCPAP or IFD and studied prospectively for changes in oxygen requirement and/or respiratory rate. The requirement for mechanical ventilation, complications of treatment, and effects on mid-term outcome were also evaluated.
RESULTS—Use of the IFD had a significantly beneficial effect on both oxygen requirement and respiratory rate (p < 0.0001) when compared with nCPAP. Moreover, O2 requirement and respiratory rate were significantly decreased by four hours (p < 0.001 and p < 0.03 respectively). The probability of remaining supplementary oxygen free over the first 48 hours of treatment was significantly higher in patients treated with the IFD than with nCPAP (p < 0.02). IFD treated patients had a higher success (weaning) rate (94% v 72%) and shorter duration of treatment (49.3 (31) v 56 (29.7) hours respectively; mean (SD)), although the difference was not significant.
CONCLUSIONS—IFD appears to be a feasible device for managing respiratory distress syndrome in preterm infants, and benefits may be had with regard to oxygen requirement and respiratory rate when compared with nCPAP. The trend towards reduced requirement for mechanical ventilation, shorter clinical recovery time, and shorter duration of treatment requires further evaluation in a multicentre randomised clinical trial.

 PMID:11517199

  2. Obstructive sleep apnea in Type 2 diabetes and impact of continuous positive airway pressure therapy on glycemic control

    PubMed Central

    Malik, Javid Ahmad; Masoodi, Shariq Rashid; Shoib, Sheikh

    2017-01-01

    Background: Obstructive sleep apnea (OSA) and type 2 diabetes mellitus (T2DM) are two interacting epidemics both with high prevalence and morbidity. Both epidemiologic and clinical studies suggest that the majority of patients with T2DM also have OSA and untreated OSA in these patients results in poor glycemic control leading to acceleration of diabetes-related complications. Objectives: To assess the prevalence and severity of OSA in T2DM patients and to assess the impact of OSA treatment on presenting symptoms and hemoglobin A1c (HbA1c). Methods: We performed polysomnography (PSG) studies and measured HbA1c in 62 consecutive patients with T2DM that were referred from various subspecialty clinics from July 2011 to August 2013. Results: In our 62 diabetic patients, 59 (95.2%) had abnormal PSG. Based on Apnea–Hypopnea Index (AHI) score, 3 (5.1%) patients had mild, 28 (47.5%) had moderate, and 28 (47.5%) had severe OSA. The mean AHI of diabetic patients was significantly more than nondiabetic patients, i.e., 25.7 versus 19.7 (P = 0.001). Variables that significantly correlated with the presence of OSA include age, gender, body mass index (BMI), hypertension, diabetes, and cardiovascular disease (P < 0.05); however, on logistic regression only BMI, hypertension, and nocturia correlated with OSA. Overall, 59% of diabetic patients showed improvement in their glycemic control as measured by HbA1c with continuous positive airway pressure (CPAP) treatment. Significant, moderate, and mild categories of treatment response were respectively observed in 7%, 20%, and 32% of patients. Conclusion: Treatment of OSA with CPAP reduces HbA1c in a significant number of diabetics. PMID:28217508

  3. Oxidative stress mediated arterial dysfunction in patients with obstructive sleep apnoea and the effect of continuous positive airway pressure treatment

    PubMed Central

    2012-01-01

    Background Several studies suggest an increase of oxidative stress and a reduction of endothelial function in obstructive sleep apnoea syndrome (OSAS). We assessed the association between OSAS, endothelial dysfunction and oxidative stress. Further aim was to evaluate the effect of nasal continuous positive airway pressure (nCPAP) on oxidative stress and arterial dysfunction. Methods We studied 138 consecutive patients with heavy snoring and possible OSAS. Patients underwent unattended overnight home polysomnography. Ten patients with severe OSAS were revaluated after 6 months of nCPAP therapy. To assess oxidative stress in vivo, we measured urinary 8-iso-PGF2α and serum levels of soluble NOX2-derived peptide (sNOX2-dp). Serum levels of nitrite/nitrate (NOx) were also determined. Flow-mediated brachial artery dilation (FMD) was measured to asses endothelial function. Results Patients with severe OSAS had higher urinary 8-iso-PGF2α (p<0.001) and serum NOX2 and lower NOx. A negative association was observed between FMD and OSA severity. Apnea/hypopnea index was significantly correlated with the indices of central obesity and with urinary 8-isoprostanes (r=0.298, p<0.001). The metabolic syndrome (t=-4.63, p<0.001) and urinary 8-isoprostanes (t=-2.02, p<0.05) were the only independent predictors of FMD. After 6-months nCPAP treatment, a significant decrease of serum NOX2, (p<0.005) and urinary 8-iso-PGF2α (p<0.01) was observed, while serum NOx showed only a minor increase. A statistically significant increase of FMD was observed (from 3.6% to 7.0%). Conclusions The results of our study indicate that patients with OSAS and cardiometabolic comorbidities have increased oxidative stress and arterial dysfunction that are partially reversed by nCPAP treatment. PMID:22824065

  4. Effects of continuous positive airway pressure on energy intake in obstructive sleep apnea: A pilot sham-controlled study

    PubMed Central

    Shechter, Ari; Kovtun, Kyle; St-Onge, Marie-Pierre

    2016-01-01

    Obesity is among the leading risk factors for obstructive sleep apnea (OSA). A reciprocal relationship between obesity and OSA has been proposed, which may be due to excessive food intake. We conducted a pilot study to test the effects of continuous positive airway pressure (CPAP) on energy intake (EI) in OSA patients using a sham-controlled crossover design. In-laboratory total daily EI was assessed after 2 mo of active and sham CPAP. Four men were enrolled (age ± SEM: 51.8 ± 2.1 y; body mass index: 31.5 ± 1.5 kg/m2). All received active treatment first. Meals (breakfast, lunch, dinner, snack) were served in excess portions at fixed times and additional palatable snacks were freely available throughout the day. Total EI was lower after active (3744 ± 511 kcal/d) vs. sham (4030 ± 456 kcal/d) CPAP but this difference was not significant (p = 0.51) due to variability in the free snack intake. When only fixed eating occasions were considered, daily EI was significantly lower in the active (3105 ± 513 kcal/d) vs. sham (3559 ± 420 kcal/d) condition (p = 0.006). This small pilot and feasibility study is the first to utilize a sham-controlled design to investigate the effects of CPAP treatment on objective measures of EI. Findings suggest that CPAP may cause a reduction in fixed meal intake. In demonstrating feasibility of study methodology, our study also suggests a larger randomized sham-controlled trial be conducted to fully characterize the effects of CPAP treatment on EI and energy balance overall. PMID:27769851

  5. 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

  6. Elective nasal continuous positive airway pressure to support respiration after prolonged ventilation in infants after congenital cardiac surgery

    PubMed Central

    Gandhi, Hemang; Mishra, Amit; Thosani, Rajesh; Acharya, Himanshu; Shah, Ritesh; Surti, Jigar; Sarvaia, Alpesh

    2017-01-01

    Background: We sought to compare the effectiveness of oxygen (O2) treatment administered by an O2 mask and nasal continuous positive airway pressure (NCPAP) in infants after congenital cardiac surgery. Methods: In this retrospective observational study, 54 infants undergoing corrective cardiac surgery were enrolled. According to the anesthesiologist's preference, the patients ventilated for more than 48 h were either put on NCPAP or O2 mask immediately after extubation. From pre-extubation to 24 h after treatment, arterial blood gas and hemodynamic data were measured. Results: After 24 h of NCPAP institution, the patients showed a significant improvement in oxygenation compared to O2 mask group. Respiratory rate (per minute) decreased from 31.67 ± 4.55 to 24.31 ± 3.69 (P < 0.0001), PO2 (mmHg) increased from 112.12 ± 22.83 to 185.74 ± 14.81 (P < 0.0001), and PCO2 (mmHg) decreased from 42.88 ± 5.01 to 37.00 ± 7.22 (P < 0.0076) in patients on NCPAP. In this group, mean pediatric cardiac surgical Intensive Care Unit (PCSICU) stay was 4.72 ± 1.60 days, with only 2 (11.11%) patients requiring re-intubation. Conclusion: NCPAP can be used safely and effectively in infants undergoing congenital cardiac surgery to improve oxygenation/ventilation. It also reduces the work of breathing, PCSICU stay, and may reduce the likelihood of re-intubation. PMID:28163425

  7. The effect of a bellows leak in an Ohmeda 7810 ventilator on room contamination, inspired oxygen, airway pressure, and tidal volume.

    PubMed

    Lampotang, Samsun; Sanchez, Justin C; Chen, Baixi; Gravenstein, Nikolaus

    2005-07-01

    We investigated the effect of a small bellows leak (bellows full at end-expiration) on inspired oxygen fraction (Fio(2)), exhaled tidal volume (Vt), airway pressure, and room contamination in an oxygen-driven anesthesia ventilator (Ohmeda 7810, Madison, WI). CO(2) concentration at the ventilator exhalation valve, Fio(2), Vt, and airway pressure were measured (n = 3) while ventilating a CO(2)-producing test lung at 8 breaths/min and an inspiratory/expiratory ratio of 1:2, with and without a bellows leak (4-mm-long tear). Set Vt was 400, 600, 800, and 1000 mL. Fresh gas flow (FGF) was 0.3 L/min O(2) and (a) 5.0 L/min air, (b) 2.0 L/min air, and (c) 0.2 L/min nitrogen. There was no clinical difference in Fio(2), Vt, PIP (peak inspiratory pressure) and PEEP (positive end-expiratory pressure), with and without a 4-mm bellows tear, at all FGFs and Vt settings. CO(2) at the ventilator exhalation valve was always nonzero with a bellows leak, indicating that CO(2)-laden circuit gas was contaminating the drive gas via the bellows leak. A 4-mm bellows tear in an Ohmeda 7810 ventilator allows anesthetic gases to contaminate ambient air but does not cause clinically significant changes in Fio(2), exhaled Vt, PIP, or PEEP.

  8. Sleep and neuromuscular disease: bilevel positive airway pressure by nasal mask as a treatment for sleep disordered breathing in patients with neuromuscular disease

    PubMed Central

    Guilleminault, C.; Philip, P.; Robinson, A.

    1998-01-01

    OBJECTIVE—Investigation of the therapeutic effects of bilevel positive airway pressure delivered by nasal mask in patients with neuromuscular disease.
METHODS—20 patients with neuromuscular disease were evaluated for symptoms of nocturnal sleep disruption. These symptoms included daytime tiredness, fatigue, sleepiness, and complaints of insomnia. The patients were studied with nocturnal polysomnograms and daytime multiple sleep latency tests (MSLT). Their immediate and long term responses to bilevel positive airway pressure were also investigated. The study took place at the Stanford University Sleep Disorders Clinic. Some of the polygraphic evaluations were performed with portable equipment in the patients' homes. The reported population comprised 20 patients, all of whom had progressive neuromuscular disease. Five of the patients were women. Four patients had muscular dystrophy, six had myotonic dystrophy, and two patients each had mitochondrial myopathy and glycogen storage disease. Two patients had post-traumatic lesions, one bulbar and the other phrenic. The remaining patients had vascular myopathy, unclassified myopathy, syringomyelia, and slow evolving spinocerebellar degeneration.
RESULTS—19 of the 20 patients accepted some form of non-invasive ventilation. All but one of these were initially maintained on bilevel positive airway pressure spontaneous (S) mode, although one patient required a switch to the timed (T) mode within a year. The mean expiratory positive airway pressure (EPAP) used was 4.5 with a range of 4 to 5 cm H2O. The mean inspiratory positive airway pressure (IPAP) was 11.5, range 9 to 14 cm H2O. Before treatment the MSLTs were ⩽ 8 minutes in 11 of the patients. The overall mean score was 8.2 (SD) 1.3 minutes. After long term treatment the mean MSLT was 12.5 (SD 2) minutes and the mean ESS score was 7 (SD 3). During the mean 3.5 years of follow up, three patients needed supplemental oxygen at a flow of 0.5 to 1.0 l/min bled into

  9. Jet ventilation for surgical interventions in the upper airway.

    PubMed

    Biro, Peter

    2010-09-01

    The clinical applications of jet ventilation (JV) in ear, nose, and throat surgery can be best understood by the characteristics that distinguish this form of ventilation from conventional positive pressure ventilation. By definition, JV is based on the application of gas portions under high pressure through an unblocked catheter into the airway, which is open to the ambient air. Beneficial opportunities arise in JV, which otherwise are not available in regular ventilation.

  10. Evaluation of an oral appliance in patients with mild to moderate obstructive sleep apnea syndrome intolerant to continuous positive airway pressure use: Preliminary results.

    PubMed

    Cantore, S; Ballini, A; Farronato, D; Malcangi, G; Dipalma, G; Assandri, F; Garagiola, U; Inchingolo, F; De Vito, D; Cirulli, N

    2016-06-01

    Obstructive sleep apnea syndrome (OSAS) is a phenomenon of repeated, episodic reduction, or cessation of airflow (hypopnea/apnea) as a result of upper airways obstruction. First-line treatment in younger children is adenotonsillectomy, although other available treatment options in middle-aged adults include continuous positive airways pressure (CPAP) and airway adjuncts. Oral appliances (OA) are a viable treatment alternative in patients with OSAS.The objective of this study was to assess, in a 1-year follow-up study, an OA in OSAS patients. The participants were subjected to polysomnographic examination with a validated device (MicroMESAM). Eight participants were fitted with a Thornton Adjustable Positioner (TAP). The participants were asked to wear the test appliance for 7 nights, and in case of compliance, for 6 months. The selected patients record their usage of the appliance and any adverse effects in a treatment journal. The research focused on the following outcomes: sleep apnea (i.e. reduction in the apnea/hypopnea index) and the effect of oral appliances on daytime function.In conclusion, the results suggest that OA have a definite role in the treatment of snoring and sleep apnea.

  11. Long-term effects of treatment with nasal continuous positive airway pressure on lung function in patients with overlap syndrome.

    PubMed

    de Miguel, Javier; Cabello, Jorge; Sánchez-Alarcos, José M F; Alvarez-Sala, Rudolfo; Espinós, Domingo; Alvarez-Sala, José L

    2002-03-01

    We assessed the effects of chronic nasal continuous positive airway pressure (CPAP) therapy on lung function in a series of unselected patients with overlap syndrome, and we determined whether there were differences in the response induced by CPAP between hypercapnic (PaCO2 > or =45 mm Hg) and eucapnic patients with overlap syndrome. The study population included 55 unselected patients (48 men, mean age of 58.5 +/- 10.5 years) with a concurrent diagnosis of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea-hypopnea syndrome (OSAHS) who had been referred to the Department of Pulmonology of our hospital over 2 consecutive years and in whom work-up studies resulted in the prescription of nasal CPAP therapy. An apnea-hypopnea index (AHI) greater than or equal to 10 in the cardiorespiratory polygraphy was required for the diagnosis of OSAHS. A forced expiratory volume in one second (FEV1) less than 80% and FEV1-forced vital capacity (FVC) ratio less than 70% of the reference values were required for the diagnosis of COPD. Control lung function studies and arterial blood gas measurements were performed at 6 and 18 months of CPAP therapy. These patients with overlap syndrome accounted for 28.5% of all patients with OSAHS treated with CPAP during the study period. The mean AHI was 37.3 +/- 26.1 and the mean CPAP level 7.3 +/- 1.3 cm H2O. Thirty-three patients were hypercapnic (PaCO2 > or = 45 mm Hg) and 22 eucapnic. The hypercapnic group had higher AHI value (44.3 +/- 26.9) than the eucapnic group (28.6 +/- 21.9) (P < 0.05). After 6 months of CPAP therapy, there were statistically significant increases in PaO2, FEV1, and FVC, accompanied by significant decreases in PaCO2, serum bicarbonate levels, and alveolar-arterial oxygen difference. Response of overlap syndrome patients to CPAP therapy was superior in the hypercapnic group, particularly in relation to improvement of arterial blood gases. However, statistically significant differences in all

  12. Continuous Positive Airway Pressure for Motion Management in Stereotactic Body Radiation Therapy to the Lung: A Controlled Pilot Study

    SciTech Connect

    Goldstein, Jeffrey D.; Lawrence, Yaacov R.; Appel, Sarit; Landau, Efrat; Ben-David, Merav A.; Rabin, Tatiana; Benayun, Maoz; Dubinski, Sergey; Weizman, Noam; Alezra, Dror; Gnessin, Hila; Goldstein, Adam M.; Baidun, Khader; Segel, Michael J.; Peled, Nir; Symon, Zvi

    2015-10-01

    Objective: To determine the effect of continuous positive airway pressure (CPAP) on tumor motion, lung volume, and dose to critical organs in patients receiving stereotactic body radiation therapy (SBRT) for lung tumors. Methods and Materials: After institutional review board approval in December 2013, patients with primary or secondary lung tumors referred for SBRT underwent 4-dimensional computed tomographic simulation twice: with free breathing and with CPAP. Tumor excursion was calculated by subtracting the vector of the greatest dimension of the gross tumor volume (GTV) from the internal target volume (ITV). Volumetric and dosimetric determinations were compared with the Wilcoxon signed-rank test. CPAP was used during treatment if judged beneficial. Results: CPAP was tolerated well in 10 of the 11 patients enrolled. Ten patients with 18 lesions were evaluated. The use of CPAP decreased tumor excursion by 0.5 ± 0.8 cm, 0.4 ± 0.7 cm, and 0.6 ± 0.8 cm in the superior–inferior, right–left, and anterior–posterior planes, respectively (P≤.02). Relative to free breathing, the mean ITV reduction was 27% (95% confidence interval [CI] 16%-39%, P<.001). CPAP significantly augmented lung volume, with a mean absolute increase of 915 ± 432 cm{sup 3} and a relative increase of 32% (95% CI 21%-42%, P=.003), contributing to a 22% relative reduction (95% CI 13%-32%, P=.001) in mean lung dose. The use of CPAP was also associated with a relative reduction in mean heart dose by 29% (95% CI 23%-36%, P=.001). Conclusion: In this pilot study, CPAP significantly reduced lung tumor motion compared with free breathing. The smaller ITV, the planning target volume (PTV), and the increase in total lung volume associated with CPAP contributed to a reduction in lung and heart dose. CPAP was well tolerated, reproducible, and simple to implement in the treatment room and should be evaluated further as a novel strategy for motion management in radiation therapy.

  13. Erectile Dysfunction and Sexual Hormone Levels in Men With Obstructive Sleep Apnea: Efficacy of Continuous Positive Airway Pressure.

    PubMed

    Zhang, Xiao-Bin; Lin, Qi-Chang; Zeng, Hui-Qing; Jiang, Xing-Tang; Chen, Bo; Chen, Xiao

    2016-01-01

    In this study, the prevalence of erectile dysfunction (ED) and serum sexual hormone levels were evaluated in men with obstructive sleep apnea (OSA). In these patients, the efficacy of continuous positive airway pressure (CPAP) was determined. The 207 men (mean age 44.0 ± 11.1 years) enrolled in the study were stratified within four groups based on their apnea-hypopnea index score: simple snoring (n = 32), mild OSA (n = 29), moderate OSA (n = 38), and severe OSA (n = 108). The International Index of Erectile Dysfunction-5 (IIEF-5) score was obtained from each patient, and blood samples for the analysis of sexual hormones (prolactin, luteotropin, follicle-stimulating hormone, estradiol, progestin, and testosterone) were drawn in the morning after polysomnography. The IIEF-5 test and serum sexual hormone measurements were repeated after 3 months of CPAP treatment in 53 men with severe OSA. The prevalence of ED was 60.6 % in OSA patients overall and 72.2 % in those with severe OSA. Compared with the simple snoring group, patients with severe OSA had significantly lower testosterone levels (14.06 ± 5.62 vs. 17.02 ± 4.68, p = .018) and lower IIEF-5 scores (16.33 ± 6.50 vs. 24.09 ± 1.94, p = .001). The differences in the other sexual hormones between groups were not significant. After 3 months of CPAP treatment, there were no significant changes in sexual hormone levels, but the IIEF-5 score had improved significantly (18.21 ± 4.05 vs. 19.21 ± 3.86, p = .001). Severe OSA patients have low testosterone concentration and high ED prevalence. IIEF-5 scores increased significantly after CPAP treatment, but there was no effect on serum testosterone levels.

  14. Pressure-induced brine migration into an open borehole in a salt repository

    SciTech Connect

    Hwang, Y.; Chambre, P.L.; Lee, W.W.L.; Pigford, T.H.

    1987-06-01

    This report provides some solutions to models that predict the brine accumulation in an open borehole. In this model, brine flow rates are controlled by pressure differences between the salt and the borehole. (TEM)

  15. An automated program for reinforcement requirements for openings in cylindrical pressure vessels

    NASA Technical Reports Server (NTRS)

    Wilson, J. F.; Taylor, J. T.

    1975-01-01

    An automated interactive program for calculating the reinforcement requirements for openings in cylindrical pressure vessels subjected to internal pressure is described. The program is written for an electronic desk top calculator. The program calculates the required area of reinforcement for a given opening and compares this value with the area of reinforcement provided by a proposed design. All program steps, operating instructions, and example problems with input and sample output are documented.

  16. Estimating the diameter of airways susceptible for collapse using crackle sound.

    PubMed

    Majumdar, Arnab; Hantos, Zoltán; Tolnai, József; Parameswaran, Harikrishnan; Tepper, Robert; Suki, Béla

    2009-11-01

    Airways that collapse during deflation generate a crackle sound when they reopen during subsequent reinflation. Since each crackle is associated with the reopening of a collapsed airway, the likelihood of an airway to be a crackle source is identical to its vulnerability to collapse. To investigate this vulnerability of airways to collapse, crackles were recorded during the first inflation of six excised rabbit lungs from the collapsed state, and subsequent reinflations from 5, 2, 1, and 0 cmH(2)O end-expiratory pressure levels. We derived a relationship between the amplitude of a crackle sound at the trachea and the generation number (n) of the source airway where the crackle was generated. Using an asymmetrical tree model of the rabbit airways with elastic walls, airway vulnerability to collapse was also determined in terms of airway diameter D. During the reinflation from end-expiratory pressure = 0 cmH(2)O, the most vulnerable airways were estimated to be centered at n = 12 with a peak. Vulnerability in terms of D ranged between 0.1 and 1.3 mm, with a peak at 0.3 mm. During the inflation from the collapsed state, however, vulnerability was much less localized to a particular n or D, with maximum values of n = 8 and D = 0.75 mm. Numerical simulations using a tree model that incorporates airway opening and closing support these conclusions. Thus our results indicate that there are airways of a given range of diameters that can become unstable during deflation and vulnerable to collapse and subsequent injury.

  17. Airflow behavior changes in upper airway caused by different head and neck positions: Comparison by computational fluid dynamics.

    PubMed

    Wei, Wei; Huang, Shi-Wei; Chen, Lian-Hua; Qi, Yang; Qiu, Yi-Min; Li, Shi-Tong

    2017-02-08

    The feasibility of computational fluid dynamics (CFD) to evaluate airflow characteristics in different head and neck positions has not been established. This study compared the changes in volume and airflow behavior of the upper airway by CFD simulation to predict the influence of anatomical and physiological airway changes due to different head-neck positions on mechanical ventilation. One awake volunteer with no risk of difficult airway underwent computed tomography in neutral position, extension position (both head and neck extended), and sniffing position (head extended and neck flexed). Three-dimensional airway models of the upper airway were reconstructed. The total volume (V) and narrowest area (Amin) of the airway models were measured. CFD simulation with an Spalart-Allmaras model was performed to characterize airflow behavior in neutral, extension, and sniffing positions of closed-mouth and open-mouth ventilation. The comparison result for V was neutral pressure drop and velocity increasing were more obvious in neutral than sniffing or extension position at the same airflow rate. In sniffing position, pressure differences decreased and velocity remained almost constant. Recirculation airflow was generated near the subglottic region in neutral and extension positions. Sniffing position improves airway patency by increasing airway volume and decreasing airway resistance, suggesting that sniffing position may be the optimal choice for mask ventilation.

  18. Cerebral hemodynamics in patients with obstructive sleep apnea syndrome monitored with near-infrared spectroscopy (NIRS) during positive airways pressure (CPAP) therapy: a pilot study

    NASA Astrophysics Data System (ADS)

    Zhang, Zhongxing; Schneider, Maja; Laures, Marco; Fritschi, Ursula; Lehner, Isabella; Qi, Ming; Khatami, Ramin

    2014-03-01

    In obstructive sleep apnea syndrome (OSA) the periodic reduction or cessation of breathing due to narrowing or occlusion of the upper airway during sleep leads to daytime symptoms and increased cardiovascular risk, including stroke. The higher risk of stroke is related to the impairment in cerebral vascular autoregulation. Continuous positive airways pressure (CPAP) therapy at night is the most effective treatment for OSA. However, there is no suitable bedside monitoring method evaluating the treatment efficacy of CPAP therapy, especially to monitor the recovery of cerebral hemodynamics. NIRS is ideally suited for non-invasive monitoring the cerebral hemodynamics during sleep. In this study, we will for first time assess dynamic changes of cerebral hemodynamics during nocturnal CPAP therapy in 3 patients with OSA using NIRS. We found periodic oscillations in HbO2, HHb, tissue oxygenation index (TOI) and blood volume associated with periodic apnea events without CPAP in all OSA patients. These oscillations were gradually attenuated and finally eliminated with the stepwise increments of CPAP pressures. The oscillations were totally eliminated in blood volume earlier than in other hemodynamic parameters. These results suggested that 1) the cerebral hemodynamic oscillations induced by OSA events can effectively be attenuated by CPAP therapy, and 2) blood flow and blood volume recovered first during CPAP therapy, followed by the recovery of oxygen consumption. Our study suggested that NIRS is a useful tool to evaluate the efficacy of CPAP therapy in patients with OSA bedside and in real time.

  19. [Pulmonary mechanics and small airways in patent ductus arteriosus and interventricular communication, in relation to pulmonary arterial flow and pressure].

    PubMed

    Martínez-Guerra, M L; Fernández-Bonetti, P; Peraza, C; Lupi-Herrera, E

    1982-01-01

    Eighteen patients with ventricular septal defect or patent ductus arteriosus were studied to investigate the effects of an increase of pulmonary hypertension. In general group II showed similar results as previously reported in patients with atrial septal defect without pulmonary hypertension. In group I, we found an increased frequency of functional abnormalities in the small airways. We do not have a definitive explanation for the origin of these differences.

  20. Fracture opening/propagation behavior and their significance on pressure-time records during hydraulic fracturing

    SciTech Connect

    Takashi Kojima; Yasuhiko Nakagawa; Koji Matsuki; Toshiyuki Hashida

    1992-01-01

    Hydraulic fracturing with constant fluid injection rate was numerically modeled for a pair of rectangular longitudinal fractures intersecting a wellbore in an impermeable rock mass, and numerical calculations have been performed to investigate the relations among the form of pressure-time curves, fracture opening/propagation behavior and permeability of the mechanically closed fractures. The results have shown that both permeability of the fractures and fluid injection rate significantly influence the form of the pressure-time relations on the early stage of fracture opening. Furthermore it has been shown that wellbore pressure during fracture propagation is affected by the pre-existing fracture length.

  1. The use of auto-titrating continuous positive airway pressure for treatment of adult obstructive sleep apnea. An American Academy of Sleep Medicine review.

    PubMed

    Berry, Richard B; Parish, James M; Hartse, Kristyna M

    2002-03-15

    This paper reviews the efficacy of auto-titrating continuous positive airway pressure (APAP) for treatment of obstructive sleep apnea. It is based on a review of 30 articles published in peer review journals conducted by a task force appointed by the American Academy of Sleep Medicine to develop practice parameters for use of APAP devices for treatment of obstructive sleep apnea (OSA). The data indicate that APAP can be used to treat many patients with OSA (auto-adjusting) or to identify an effective optimal fixed level of continuous positive airway pressure (CPAP) for treatment (auto-titration). Patients with significant congestive heart failure, chronic obstructive pulmonary disease (COPD), or significant amounts of central apnea were excluded from many treatment trials and there is insufficient evidence that APAP can be used to treat these patients. Many clinical trials have been performed in patients already on CPAP or with the initial APAP night in a laboratory setting. At this time only a few studies have evaluated initial titration with APAP in CPAP-naïve patients in an unattended setting. Further studies of APAP in this circumstance are needed. No studies have systematically compared the efficacy of one APAP technology with another. Devices using different technology may not give the same results in a given patient. Devices solely dependent on vibration may not work in non-snorers or patient who have undergone upper-airway surgery. High mask or mouth leaks may prevent adequate titration in devices monitoring snoring, flow, or impedance (forced oscillation technique). Review of the raw data to identify periods of high leak was performed in several of the APAP titration studies, to identify a pressure for fixed CPAP treatment or to determine if the titration was adequate. There is conflicting evidence for and against the premise that treatment with APAP increases acceptance and adherence compared to fixed CPAP. In studies demonstrating an increase in

  2. Factors affecting opening and filling pressures in the lungs of the lizard Pogona vitticeps.

    PubMed

    Wood, P G; Daniels, C B

    1996-02-01

    We have previously reported that levels of pulmonary surfactant in the lungs of the lizard Pogona vitticeps increase with increasing body temperature. Static lung compliance decreases with increasing body temperature, and is only marginally affected by the presence of surfactant. Here, we examined the effects of surfactant, temperature, ventilatory pattern and autonomic neurotransmitters on opening and filling pressures. Isolated lungs were ventilated at either 18 or 37 degrees C at low, intermediate and high ventilatory regimes. The effects of acetylcholine and adrenaline were examined using an isolated perfused lung preparation at 27 degrees C. Changing ventilatory pattern or experimental temperature had no effect on either filling or opening pressures. Removal of surfactant increased both opening and filling pressures. Adrenaline administration reduced opening and filling pressures. Normal variations in surfactant levels, which occur with changes in body temperature, do not affect either opening or filling pressures. A critical amount of surfactant may be necessary to prevent adhesion of epithelial surfaces in the lungs of Pogona vitticeps. The anti-glue function of pulmonary surfactant may be more important at 18 than at 37 degrees C.

  3. Web-Based Access to Positive Airway Pressure Usage with or without an Initial Financial Incentive Improves Treatment Use in Patients with Obstructive Sleep Apnea

    PubMed Central

    Kuna, Samuel T.; Shuttleworth, David; Chi, Luqi; Schutte-Rodin, Sharon; Friedman, Eliot; Guo, Hengyi; Dhand, Sandeep; Yang, Lin; Zhu, Jingsan; Bellamy, Scarlett L.; Volpp, Kevin G.; Asch, David A.

    2015-01-01

    Study Objectives: We tested whether providing adults with obstructive sleep apnea (OSA) with daily Web-based access to their positive airway pressure (PAP) usage over 3 mo with or without a financial incentive in the first week improves adherence and functional outcomes. Setting: Academic- and community-based sleep centers. Participants: One hundred thirty-eight adults with newly diagnosed OSA starting PAP treatment. Interventions: Participants were randomized to: usual care, usual care with access to PAP usage, or usual care with access to PAP usage and a financial incentive. PAP data were transmitted daily by wireless modem from the participants' PAP unit to a website where hours of usage were displayed. Participants in the financial incentive group could earn up to $30/day in the first week for objective PAP use ≥ 4 h/day. Measurements and Results: Mean hours of daily PAP use in the two groups with access to PAP usage data did not differ from each other but was significantly greater than that in the usual care group in the first week and over 3 mo (P < 0.0001). Average daily use (mean ± standard deviation) during the first week of PAP intervention was 4.7 ± 3.3 h in the usual care group, and 5.9 ± 2.5 h and 6.3 ± 2.5 h in the Web access groups with and without financial incentive respectively. Adherence over the 3-mo intervention decreased at a relatively constant rate in all three groups. Functional Outcomes of Sleep Questionnaire change scores at 3 mo improved within each group (P < 0.0001) but change scores of the two groups with Web access to PAP data were not different than those in the control group (P > 0.124). Conclusions: Positive airway pressure adherence is significantly improved by giving patients Web access to information about their use of the treatment. Inclusion of a financial incentive in the first week had no additive effect in improving adherence. Citation: Kuna ST, Shuttleworth D, Chi L, Schutte-Rodin S, Friedman E, Guo H, Dhand S, Yang

  4. A Rotational Pressure-Correction Scheme for Incompressible Two-Phase Flows with Open Boundaries

    PubMed Central

    Dong, S.; Wang, X.

    2016-01-01

    Two-phase outflows refer to situations where the interface formed between two immiscible incompressible fluids passes through open portions of the domain boundary. We present several new forms of open boundary conditions for two-phase outflow simulations within the phase field framework, as well as a rotational pressure correction based algorithm for numerically treating these open boundary conditions. Our algorithm gives rise to linear algebraic systems for the velocity and the pressure that involve only constant and time-independent coefficient matrices after discretization, despite the variable density and variable viscosity of the two-phase mixture. By comparing simulation results with theory and the experimental data, we show that the method produces physically accurate results. We also present numerical experiments to demonstrate the long-term stability of the method in situations where large density contrast, large viscosity contrast, and backflows occur at the two-phase open boundaries. PMID:27163909

  5. A Rotational Pressure-Correction Scheme for Incompressible Two-Phase Flows with Open Boundaries.

    PubMed

    Dong, S; Wang, X

    2016-01-01

    Two-phase outflows refer to situations where the interface formed between two immiscible incompressible fluids passes through open portions of the domain boundary. We present several new forms of open boundary conditions for two-phase outflow simulations within the phase field framework, as well as a rotational pressure correction based algorithm for numerically treating these open boundary conditions. Our algorithm gives rise to linear algebraic systems for the velocity and the pressure that involve only constant and time-independent coefficient matrices after discretization, despite the variable density and variable viscosity of the two-phase mixture. By comparing simulation results with theory and the experimental data, we show that the method produces physically accurate results. We also present numerical experiments to demonstrate the long-term stability of the method in situations where large density contrast, large viscosity contrast, and backflows occur at the two-phase open boundaries.

  6. Effects of Continuous Positive Airway Pressure on Cognitive and Functional Outcome of Stroke Patients with Obstructive Sleep Apnea: A Randomized Controlled Trial

    PubMed Central

    Aaronson, Justine A.; Hofman, Winni F.; van Bennekom, Coen A.M.; van Bezeij, Tijs; van den Aardweg, Joost G.; Groet, Erny; Kylstra, Wytske A.; Schmand, Ben

    2016-01-01

    Study Objectives: Obstructive sleep apnea (OSA) in stroke patients is associated with worse functional and cognitive status during inpatient rehabilitation. We hypothesized that a four-week period of continuous positive airway pressure (CPAP) treatment would improve cognitive and functional outcomes. Methods: We performed a randomized controlled trial in stroke patients admitted to a neurorehabilitation unit. Patients were assigned to rehabilitation treatment as usual (control group) or to CPAP treatment (CPAP group). Primary outcomes were cognitive status measured by neuropsychological examination, and functional status measured by two neurological scales and a measure of activities of daily living (ADL). Secondary measures included sleepiness, sleep quality, fatigue, and mood. Tests were performed at baseline and after the four-week intervention period. Results: We randomly assigned 20 patients to the CPAP group and 16 patients to the control group. The average CPAP compliance was 2.5 hours per night. Patients in the CPAP group showed significantly greater improvement in the cognitive domains of attention and executive functioning than the control group. CPAP compliance was associated with greater improvement in cognitive functioning. CPAP did not result in measurable improvement on measures of neurological status or ADL, or on any of the secondary measures. Conclusions: CPAP treatment improves cognitive functioning of stroke patients with OSA. Commentary: A commentary on this article appears in this issue on page 467. Citation: Aaronson JA, Hofman WF, van Bennekom CA, van Bezeij T, van den Aardweg JG, Groet E, Kylstra WA, Schmand B. Effects of continuous positive airway pressure on cognitive and functional outcome of stroke patients with obstructive sleep apnea: a randomized controlled trial. J Clin Sleep Med 2016;12(4):533–541. PMID:26888587

  7. Effectiveness of flow inflating device in providing Continuous Positive Airway Pressure for critically ill children in limited-resource settings: A prospective observational study

    PubMed Central

    Anitha, G. Fatima Shirly; Velmurugan, Lakshmi; Sangareddi, Shanthi; Nedunchelian, Krishnamurthy; Selvaraj, Vinoth

    2016-01-01

    Background and Aims: Noninvasive ventilation (NIV) is an emerging popular concept, which includes bi-level positive airway pressure or continuous positive airway pressure (CPAP). In settings with scarce resources for NIV machines, CPAP can be provided through various indigenous means and one such mode is flow inflating device - Jackson-Rees circuit (JR)/Bain circuit. The study analyses the epidemiology, various clinical indications, predictors of CPAP failure, and stresses the usefulness of flow inflating device as an indigenous way of providing CPAP. Methods: A prospective observational study was undertaken in the critical care unit of a Government Tertiary Care Hospital, from November 2013 to September 2014. All children who required CPAP in the age group 1 month to 12 years of both sexes were included in this study. They were started on indigenous CPAP through flow inflating device on clinical grounds based on the pediatric assessment triangle, and the duration and outcome were analyzed. Results: This study population included 214 children. CPAP through flow inflating device was successful in 89.7% of cases, of which bronchiolitis accounted for 98.3%. A prolonged duration of CPAP support of >96 h was required in pneumonia. CPAP failure was noted in 10.3% of cases, the major risk factors being children <1 year and pneumonia with septic shock. Conclusion: We conclude that flow inflating devices - JR/Bain circuit are effective as an indigenous CPAP in limited resource settings. Despite its benefits, CPAP is not a substitute for invasive ventilation, as when the need for intubation arises timely intervention is needed. PMID:27630454

  8. Effect of Positive Airway Pressure Therapy on Body Mass Index in Obese Patients With Obstructive Sleep Apnea Syndrome: A Prospective Study.

    PubMed

    Rishi, Muhammad Adeel; Copur, Ahmet Sinan; Nadeem, Rashid; Fulambarker, Ashok

    2016-01-01

    Because obesity is a common cause of obstructive sleep apnea syndrome (OSAS), weight loss can be an effective treatment. OSAS also may cause weight gain in some patients. Effective treatment of sleep apnea may facilitate weight loss in obese patients. We hypothesize that positive airway pressure (PAP) therapy is associated with weight loss in obese patients with OSAS. This was a single-center observational prospective cohort study. Forty-five patients were diagnosed with OSAS after polysomnographic analysis in sleep laboratory and underwent continuous positive airway pressure titration. Patients were followed for 3 months in terms of change in body mass index (BMI) and compliance with PAP therapy. Of the 45 patients recruited, 3 patients were eliminated because of miss recruitment. Nine patients had incomplete data, and the rest (n = 33) were included for analysis. The mean age was 54.9 ± 16.9 years (mean ± SD), 93.9% were male, and 90.9% were whites. Mean apnea-hypopnea index was 36.3 ± 28.17 events per hour. Mean BMI before treatment was 34.7 ± 3.9 kg/m. Fifteen patients (45.5%) were compliant with therapy of OSAS with PAP. There was no difference in age, gender, neck circumference, BMI, and apnea-hypopnea index of patients compliant to therapy when compared with those who were not. There was a significant decrease in BMI in patients compliant with PAP therapy compared with noncompliant patients (-1.2 ± 0.7 vs. 0.3 ± 0.9 kg/m, P ≤ 0.001). PAP therapy may cause significant loss of weight within 3 months in obese patients with OSAS. Further study is needed to elucidate the physiological basis of this change.

  9. Improved Oxygenation 24 Hours After Transition to Airway Pressure Release Ventilation or High-Frequency Oscillatory Ventilation Accurately Discriminates Survival in Immunocompromised Pediatric Patients With Acute Respiratory Distress Syndrome*

    PubMed Central

    Yehya, Nadir; Topjian, Alexis A.; Thomas, Neal J.; Friess, Stuart H.

    2014-01-01

    Objectives Children with an immunocompromised condition and requiring invasive mechanical ventilation have high risk of death. Such patients are commonly transitioned to rescue modes of non-conventional ventilation, including airway pressure release ventilation and high-frequency oscillatory ventilation, for acute respiratory distress syndrome refractory to conventional ventilation. Our aim was to describe our experience with airway pressure release ventilation and high-frequency oscillatory ventilation in children with an immunocompromised condition and acute respiratory distress syndrome refractory to conventional ventilation and to identify factors associated with survival. Design Retrospective cohort study. Setting Tertiary care, university-affiliated PICU. Patients Sixty pediatric patients with an immunocompromised condition and acute respiratory distress syndrome refractory to conventional ventilation transitioned to either airway pressure release ventilation or high-frequency oscillatory ventilation. Interventions None. Measurements and Main Results Demographic data, ventilator settings, arterial blood gases, oxygenation index, and Pao2/Fio2 were recorded before transition to either mode of nonconventional ventilation and at predetermined intervals after transition for up to 5 days. Mortality in the entire cohort was 63% and did not differ between patients transitioned to airway pressure release ventilation and high-frequency oscillatory ventilation. For both airway pressure release ventilation and high-frequency oscillatory ventilation, improvements in oxygenation index and Pao2/Fio2 at 24 hours expressed as a fraction of pretransition values (oxygenation index24/oxygenation indexpre and Pao2/Fio224/Pao2/FIO2pre) reliably discriminated nonsurvivors from survivors, with receiver operating characteristic areas under the curves between 0.89 and 0.95 (p for all curves < 0.001). Sensitivity-specificity analysis suggested that less than 15% reduction in

  10. Non-Axisymmetric Inflatable Pressure Structure (NAIPS) Concept that Enables Mass Efficient Packageable Pressure Vessels with Sealable Openings

    NASA Technical Reports Server (NTRS)

    Doggett, William R.; Jones, Thomas C.; Kenner, Winfred S.; Moore, David F.; Watson, Judith J.; Warren, Jerry E.; Makino, Alberto; Yount, Bryan; Selig, Molly; Shariff, Khadijah; Litteken, Douglas; Mikulas, Martin M., Jr.

    2016-01-01

    Achieving minimal launch volume and mass are always important for space missions, especially for deep space manned missions where the costs required to transport mass to the destination are high and volume in the payload shroud is limited. Pressure vessels are used for many purposes in space missions including habitats, airlocks, and tank farms for fuel or processed resources. A lucrative approach to minimize launch volume is to construct the pressure vessels from soft goods so that they can be compactly packaged for launch and then inflated en route or at the final destination. In addition, there is the potential to reduce system mass because the packaged pressure vessels are inherently robust to launch loads and do not need to be modified from their in-service configuration to survive the launch environment. A novel concept is presented herein, in which sealable openings or hatches into the pressure vessels can also be fabricated from soft goods. To accomplish this, the structural shape is designed to have large regions where one principal stress is near zero. The pressure vessel is also required to have an elongated geometry for applications such as airlocks.

  11. Experiment and numerical simulation of cavitation performance on a pressure-regulating valve with different openings

    NASA Astrophysics Data System (ADS)

    Qu, W. S.; Tan, L.; Cao, S. L.; Xu, Y.; Huang, J.; Xu, Q. H.

    2015-01-01

    As a kind of widely used device in pipe system for pressure and flow rate regulating, the valve would experience cavitation in the case when a sharp pressure drop occurs, which will induce the energy loss, noise and vibration of pipeline system, and even operational accidents. The experiment on flow resistance coefficient of a DN600 pressure-regulating valve under operation conditions from 0% to 100% openings is conducted. Based on the RNG k-e turbulence model and the Rayleigh-Plesset cavitation equation, a set of computational model is developed to simulate the turbulent flow in the valve under operational conditions from 0% to 100% openings. The computational results of flow resistance coefficient are compared to the experimental data. And the numerical simulation is employed to predict the cavitation performance of the valve at different inlet flow conditions. The transient cavitating flow is calculated to reveal the time evolution of cavitation in the valve.

  12. A servo-control system for open- and closed-loop blood pressure regulation.

    PubMed

    Nafz, B; Persson, P B; Ehmke, H; Kirchheim, H R

    1992-02-01

    An electropneumatic servo-control system is described that can reduce and control arterial blood pressure in experimental animals. The device has been proved useful in the analysis of pressure-dependent physiological processes and allows the following two modes of operation: 1) a conventional open-loop setting that will reduce arterial pressure to a preselected set point and 2) a closed-loop mode that enables an adjustment to a dynamic pressure set point (i.e., the controlled pressure is reduced to a constant value below a reference pressure). A pneumatic servo-control mechanism was chosen to provide minimal control latency. The accuracy of the system under physiological conditions is well within +/- 1 mmHg. The device can be useful in a number of studies demanding a precise regulation of local arterial pressure, such as experiments on blood flow autoregulation, arterial baroreceptor reflexes, and all experiments involving the study of pressure-dependent excretory and incretory functions of the kidney. The closed-loop setting is useful for studying physiological feedback systems.

  13. A Study of Standing Pressure Waves Within Open and Closed Acoustic Resonators

    NASA Technical Reports Server (NTRS)

    Daniels, C.; Steinetz, B.; Finkbeiner, J.; Raman, G.; Li, X.

    2002-01-01

    The first section of the results presented herein was conducted on an axisymmetric resonator configured with open ventilation ports on either end of the resonator, but otherwise closed and free from obstruction. The remaining section presents the results of a similar resonator shape that was closed, but contained an axisymmetric blockage centrally located through the axis of the resonator. Ambient air was used as the working fluid. In each of the studies, the resonator was oscillated at the resonant frequency of the fluid contained within the cavity while the dynamic pressure, static pressure, and temperature of the fluid were recorded at both ends of the resonator. The baseline results showed a marked reduction in the amplitude of the dynamic pressure waveforms over previous studies due to the use of air instead of refrigerant as the working fluid. A sharp reduction in the amplitude of the acoustic pressure waves was expected and recorded when the configuration of the resonators was modified from closed to open. A change in the resonant frequency was recorded when blockages of differing geometries were used in the closed resonator, while acoustic pressure amplitudes varied little from baseline measurements.

  14. Low pressure drop airborne molecular contaminant filtration using open-channel networks

    NASA Astrophysics Data System (ADS)

    Dallas, Andrew J.; Ding, Lefei; Joriman, Jon; Zastera, Dustin; Seguin, Kevin; Empson, James

    2006-03-01

    Airborne molecular contamination (AMC) continues to play a very decisive role in the performance of many microelectronic devices and manufacturing processes. Currently, the state of the filtration industry is such that optimum filter life and removal efficiency for AMC is offered by granular filter beds. However, the attributes that make packed beds of adsorbents extremely efficient also impart issues related to elevated filter weight and pressure drop. Most of the low pressure drop AMC filters currently offered tend to be quiet costly and contaminant nonspecific. Many of these low pressure drop filters are simply pleated combinations of various adsorptive and reactive media. On the other hand, low pressure drop filters, such as those designed as open-channel networks (OCNs), can still offer good filter life and removal efficiency, with the additional benefits of significant reductions in overall filter weight and pressure drop. Equally important for many applications, the OCN filters can reconstruct the airflow so as to enhance the operation of a tool or process. For tool mount assemblies and full fan unit filters this can result in reduced fan and blower speeds, which subsequently can provide reduced vibration and energy costs. Additionally, these low pressure drop designs can provide a cost effective way of effectively removing AMC in full fab (or HVAC) filtration applications without significantly affecting air-handling requirements. Herein, we will present a new generation of low pressure drop OCN filters designed for AMC removal in a wide range of applications.

  15. Airway management using a supraglottic airway device without endotracheal intubation for positive ventilation of anaesthetized rats.

    PubMed

    Cheong, S H; Lee, J H; Kim, M H; Cho, K R; Lim, S H; Lee, K M; Park, M Y; Yang, Y I; Kim, D K; Choi, C S

    2013-04-01

    Endotracheal intubation is often necessary for positive pressure ventilation of rats during open thoracic surgery. Since endotracheal intubation in rats is technically difficult and is associated with numerous complications, many techniques using various devices have been described in the scientific literature. In this study, we compared the effectiveness of airway management of a home-made supraglottic airway device (SAD), which is cheap to fabricate and easy to place with that of an endotracheal intubation tube in enflurane-anaesthetized rats. Twenty male Sprague-Dawley rats (200-300 g) were randomly assigned to two equal groups for positive pressure mechanical ventilation using either the SAD or an endotracheal intubation tube. The carotid artery of each rat was cannulated for continuous blood pressure measurements and obtaining blood samples for determination of oxygen tension, carbon dioxide tension, and blood acidity before, during and after SAD placement or endotracheal intubation. Proper placement of the SAD was confirmed by observing chest wall movements that coincided with the operation of the mechanical ventilator. No complications and adverse events were encountered in the rats in which the SAD was placed, during SAD placement and immediate removal, during their mechanical ventilation through the SAD, and one week after SAD removal. From the results of blood gas analyses, we conclude that anaesthetized rats can be successfully ventilated using an SAD for open thoracic surgery.

  16. 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

  17. Nearfield Unsteady Pressures at Cruise Mach Numbers for a Model Scale Counter-Rotation Open Rotor

    NASA Technical Reports Server (NTRS)

    Stephens, David B.

    2012-01-01

    An open rotor experiment was conducted at cruise Mach numbers and the unsteady pressure in the nearfield was measured. The system included extensive performance measurements, which can help provide insight into the noise generating mechanisms in the absence of flow measurements. A set of data acquired at a constant blade pitch angle but various rotor speeds was examined. The tone levels generated by the front and rear rotor were found to be nearly equal when the thrust was evenly balanced between rotors.

  18. An Open Port Sampling Interface for Liquid Introduction Atmospheric Pressure Ionization Mass Spectrometry

    SciTech Connect

    Van Berkel, Gary J.; Kertesz, Vilmos

    2015-01-01

    RATIONALE: A simple method to introduce unprocessed samples into a solvent for rapid characterization by liquid introduction atmospheric pressure ionization mass spectrometry has been lacking. The continuous flow, self-cleaning open port sampling interface introduced here fills this void. METHODS: The open port sampling interface used a vertically aligned, co-axial tube arrangement enabling solvent delivery to the sampling end of the device through the tubing annulus and solvent aspiration down the center tube and into the mass spectrometer ionization source via the commercial APCI emitter probe. The solvent delivery rate to the interface was set to exceed the aspiration rate creating a continuous sampling interface along with a constant, self-cleaning spillover of solvent from the top of the probe. RESULTS: Using the open port sampling interface with positive ion mode APCI and a hybrid quadrupole time of flight mass spectrometer, rapid, direct sampling and analysis possibilities are exemplified with plastics, ballpoint and felt tip ink pens, skin, and vegetable oils. These results demonstrated that the open port sampling interface could be used as a simple, versatile and self-cleaning system to rapidly introduce multiple types of unprocessed, sometimes highly concentrated and complex, samples into a solvent flow stream for subsequent ionization and analysis by mass spectrometry. The basic setup presented here could be incorporated with any self-aspirating liquid introduction ionization source (e.g., ESI, APCI, APPI, ICP, etc.) or any type of atmospheric pressure sampling ready mass spectrometer system. CONCLUSIONS: The open port sampling interface provides a means to introduce and quickly analyze unprocessed solid or liquid samples with liquid introduction atmospheric pressure ionization source without fear of sampling interface or ionization source contamination.

  19. An Open Port Sampling Interface for Liquid Introduction Atmospheric Pressure Ionization Mass Spectrometry

    DOE PAGES

    Van Berkel, Gary J.; Kertesz, Vilmos

    2015-01-01

    RATIONALE: A simple method to introduce unprocessed samples into a solvent for rapid characterization by liquid introduction atmospheric pressure ionization mass spectrometry has been lacking. The continuous flow, self-cleaning open port sampling interface introduced here fills this void. METHODS: The open port sampling interface used a vertically aligned, co-axial tube arrangement enabling solvent delivery to the sampling end of the device through the tubing annulus and solvent aspiration down the center tube and into the mass spectrometer ionization source via the commercial APCI emitter probe. The solvent delivery rate to the interface was set to exceed the aspiration rate creatingmore » a continuous sampling interface along with a constant, self-cleaning spillover of solvent from the top of the probe. RESULTS: Using the open port sampling interface with positive ion mode APCI and a hybrid quadrupole time of flight mass spectrometer, rapid, direct sampling and analysis possibilities are exemplified with plastics, ballpoint and felt tip ink pens, skin, and vegetable oils. These results demonstrated that the open port sampling interface could be used as a simple, versatile and self-cleaning system to rapidly introduce multiple types of unprocessed, sometimes highly concentrated and complex, samples into a solvent flow stream for subsequent ionization and analysis by mass spectrometry. The basic setup presented here could be incorporated with any self-aspirating liquid introduction ionization source (e.g., ESI, APCI, APPI, ICP, etc.) or any type of atmospheric pressure sampling ready mass spectrometer system. CONCLUSIONS: The open port sampling interface provides a means to introduce and quickly analyze unprocessed solid or liquid samples with liquid introduction atmospheric pressure ionization source without fear of sampling interface or ionization source contamination.« less

  20. Comparison of Four Different Supraglottic Airway Devices in Terms of Efficacy, Intra-ocular Pressure and Haemodynamic Parameters in Children Undergoing Ophthalmic Surgery

    PubMed Central

    Peker, Gökhan; Takmaz, Suna Akın; Baltacı, Bülent; Başar, Hülya; Kotanoğlu, Mustafa

    2015-01-01

    Objective The aim of this study was to compare insertion parameters of four different types of supraglottic airway devices (SGAD) (Classic LMA, I-gel LMA, Proseal LMA, Cobra PLA) in children undergoing ophthalmic surgery and to determine the effect on intra-ocular pressure (IOP) and haemodynamic responses during insertion. Methods Sixty American society of Anesthesiologists (ASA) I–II children aged 1–10 years undergoing extra-ocular ophthalmic surgery were randomly divided into four groups (Group LMA, Group I-gel LMA, Group PLMA and Group CPLA) in this prospective, randomised study. Anaesthesia was induced with decreasing sevoflurane concentrations (8%–2%) in a mixture of 50% N2O-O2. All SGADs were inserted under deep anaesthesia. The characteristics of insertion (number of attempts, ease and time), oropharyngeal leak pressure (OLP) and complications were recorded. IOP in both eyes, heart rate (HR), mean arterial pressure (MAP) and EtCO2 were measured before and 2 and 5 min after insertion of the SGADs. Results There was no difference between the groups in terms of the characteristics of insertion. The mean IOP did not increase significantly in all groups. MAP and HR changes were similar among the groups during follow-up. In all groups, HR increased 2 min after insertion (statistically insignificant) and returned to the baseline value 5 min after insertion. A statistically significant correlation was seen between HR increase and IOP values before and after insertion of the SGADs (p=0.006, correlation coefficient=0.352). Desaturation was seen in one patient in Groups LMA, PLMA and CPLA, and laryngospasm was seen in two patients in Group CPLA and in one patient in Group LMA. Conclusion It was seen that during insertion of Classic LMA, I-gel LMA, Proseal LMA and Cobra PLA, IOP did not increase and haemodynamic stability was maintained in children undergoing extra-ocular ophthalmic surgery. PMID:27366519

  1. Silver Dressings Augment the Ability of Negative Pressure Wound Therapy to Reduce Bacteria in a Contaminated Open Fracture Model

    DTIC Science & Technology

    2011-07-01

    ORIGINAL ARTICLE Silver Dressings Augment the Ability of Negative Pressure Wound Therapy to Reduce Bacteria in a Contaminated Open Fracture Model...contaminated by S. aureus. Key Words: Contamination, Infection, Open fracture , Negative pressure, Silver dressing. (J Trauma. 2011;71: S147–S150...is commonly used in the treatment of large wounds and acute open fractures , and has even been applied to surgical incisions in an effort to minimize

  2. Optimisation of the round window opening in cochlear implant surgery in wet and dry conditions: impact on intracochlear pressure changes.

    PubMed

    Mittmann, Philipp; Ernst, A; Mittmann, M; Todt, I

    2016-11-01

    To preserve residual hearing in cochlear implant candidates, the atraumatic insertion of the cochlea electrode has become a focus of cochlea implant research. In a previous study, intracochlear pressure changes during the opening of the round window membrane were investigated. In the current study, intracochlear pressure changes during opening of the round window membrane under dry and transfluid conditions were investigated. Round window openings were performed in an artificial cochlear model. Intracochlear pressure changes were measured using a micro-optical pressure sensor, which was placed in the apex. Openings of the round window membrane were performed under dry and wet conditions using a cannula and a diode laser. Statistically significant differences in the intracochlear pressure changes were seen between the different methods used for opening of the round window membrane. Lower pressure changes were seen by opening the round window membrane with the diode laser than with the cannula. A significant difference was seen between the dry and wet conditions. The atraumatic approach to the cochlea is assumed to be essential for the preservation of residual hearing. Opening of the round window under wet conditions produce a significant advantage on intracochlear pressure changes in comparison to dry conditions by limiting negative outward pressure.

  3. In vivo efficacy of heated and non-heated humidifiers during nasal continuous positive airway pressure (nCPAP)-therapy for obstructive sleep apnoea.

    PubMed

    Wiest, G H; Fuchs, F S; Brueckl, W M; Nusko, G; Harsch, I A; Hahn, E G; Ficker, J H

    2000-04-01

    Upper airway dryness is a frequent side-effect of nasal continuous positive airway pressure therapy (nCPAP) in obstructive sleep apnoea (OSA). In this situation, heated or non-heated passover humidifiers are often added to the nCPAP-therapy. The efficacy of these two modes in terms of increasing the absolute humidity of the inspired air in vivo has so far not been established. The present investigation was therefore designed to compare various heated and non-heated passover humidifiers in terms of the their ability to increase the absolute humidity in the inspired air during nCPAP. In six healthy test individuals, nCPAP-therapy at pressures of 5 mbar and 10 mbar was simulated, and the relative humidity and temperature of the air within the tube at the junction between CPAP tube and mask were measured. In each test person, measurements were carried out both with and without the two heated (HC 100, Fischer&Paykel Inc., New Zealand and HumidAire, ResMed Ltd., Australia) and two non-heated (Oasis and Humidifier, both from Respironics Inc., U.S.A.) passover humidifiers under steady-state conditions. The absolute humidity was calculated from the relative humidity and temperature measurements. The mean (SD) absolute humidity (gm(-3)) in the steady-state was significantly (P<0.05 higher with each of the humidifiers than that calculated when no humidifier was used. The relevant figures were as follows: no humidifier: 10(-2) (1.8) gm(-3) (at 5 mbar)/9.8 (1.8) gm(-3) (at 10 mbar); Humidifier: 16.4 (0.97)/15.6 (1.26); Oasis: 17.3 (0.97)/ 16.7 (0.93); HC100: 26.5 (1.40)/26.2 (1.23); HumidAire: 31.8 (2.50)/30.9 (2.64). The mean increase in absolute humidity (in gm(-3)) with the aid of the heated humidifiers was 16.3 (5 mbar) gm(-3)/16.4 (10 mbar) gm(-3) with HC100 and 21.6/21.1 with HumidAire, and in both cases was clearly and significantly (P=0.028) higher in comparison with the non-heated humidifiers--6.2/5.8 with Humidifier and 7.2/6.9 with Oasis. In terms of the absolute

  4. Meta-analysis of randomised controlled trials of oral mandibular advancement devices and continuous positive airway pressure for obstructive sleep apnoea-hypopnoea.

    PubMed

    Sharples, Linda D; Clutterbuck-James, Abigail L; Glover, Matthew J; Bennett, Maxine S; Chadwick, Rebecca; Pittman, Marcus A; Quinnell, Timothy G

    2016-06-01

    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.

  5. Effect of continuous positive airway pressure on arterial stiffness in patients with obstructive sleep apnea and hypertension: a meta-analysis.

    PubMed

    Lin, Xin; Chen, Gongping; Qi, Jiachao; Chen, Xiaofang; Zhao, Jiangming; Lin, Qichang

    2016-12-01

    Arterial stiffness has been recognized as a predictor of cardiovascular and all-cause mortality in hypertensive patients. However, the impact of continuous positive airway pressure (CPAP) on arterial stiffness in patients with OSA and hypertension remains inconclusive. We performed a meta-analysis to determine whether effective CPAP therapy could decrease arterial stiffness. Two reviewers independently searched PubMed, Embase, Web of Science and Cochrane Library prior to March 5, 2015. Information on characteristics of subjects, study design and pre- and post-CPAP treatment of arterial stiffness was extracted for analysis. Standardized mean difference (SMD) was used to analyze the summary estimates for CPAP therapy. Three articles with 186 patients were included in this meta-analysis, including two observational studies and one randomized controlled study. The meta-analysis showed that CPAP was associated with a statistically significant decrease in arterial stiffness in patients with OSA and hypertension (SMD = -0.65, 95 % confidence interval (CI) = -1.14 to -0.16, z = 2.60, p = 0.009). Our meta-analysis suggested that CPAP among OSA and hypertensive patients was significantly associated with a decrease in arterial stiffness. Further prospective large-scale multicenter RCTs are needed to explore the precise impact of CPAP therapy on arterial stiffness in patients with OSA and hypertension.

  6. The effect of treating obstructive sleep apnea with positive airway pressure on depression and other subjective symptoms: A systematic review and meta-analysis.

    PubMed

    Gupta, Madhulika A; Simpson, Fiona C; Lyons, Danika C A

    2016-08-01

    Patients with obstructive sleep apnea (OSA) frequently present with symptoms of depression and anxiety. The objective of this study is to determine if treatment with positive airway pressure (PAP) improves symptoms of depression and anxiety. A systematic review was conducted to identify clinical trials of PAP that contained a validated measure of depression severity. Meta-analysis was conducted for depression, anxiety, excessive daytime sleepiness (EDS), quality of life (QoL) and respiratory variables. The systematic review included 33 reports. Pre-post-test analysis of PAP showed a moderate effect size (Hedge's g, 95% CI) for depression 0.524 [0.401-0.647], but a low effect size compared to oral placebo (0.355 [0.187-0.524]) and no effect when compared to dental appliances (0.107 [-0.72-0.287]) and sham PAP (-0.049 [-0.292-0.194]). Anxiety, EDS, and QoL showed similar improvement in pre-post-test analysis, but a lack of superiority to dental appliances and sham PAP. PAP was superior to all comparators for respiratory variables. PAP has a moderate clinical effect on symptoms of depression and anxiety in OSA, but it is not superior to dental appliances or sham PAP. The improvement in subjective symptoms, such as depression and anxiety, may be mediated by patient expectations and contact with healthcare providers.

  7. Effects of Continuous Positive Airway Pressure on Cognitive Deficits in Middle-aged Patients with Obstructive Sleep Apnea Syndrome: A Meta-analysis of Randomized Controlled Trials

    PubMed Central

    Pan, Yue-Ying; Deng, Yan; Xu, Xiu; Liu, Ya-Ping; Liu, Hui-Guo

    2015-01-01

    Background: Current views on continuous positive airway pressure (CPAP) treatment to improve the cognitive deficits of patients with obstructive sleep apnea syndrome (OSAS) are controversial, so we performed a meta-analysis. Methods: A comprehensive literature search was undertaken in PubMed, CINAHL, Medline, PsycInfo, EMBASE, Cochrane Library, CNKI, WanFang, VIP, and CBMdisc for studies published from June 1971 to July 2014. The outcome measures included neuropsychological tests of the 7 cognitive domains detailed below. Results: After screening the titles and abstracts and thoroughly reading the full text, we obtained 13 studies with little risk of bias that incorporated 1744 middle-aged obese participants with mild to severe OSAS. The studies were published from 1994 to 2012. Treatment durations varied from 1 to 24 weeks. The effect sizes of attention, vigilance, processing speed, working memory, memory, verbal fluency, and visuoconstructive skills domains were −0.10 (P = 0.24), −0.12 (P = 0.04), −0.08 (P = 0.16), 0.00 (P = 0.95), −0.04 (P = 0.30), −0.06 (P = 0.34), and −0.01 (P = 0.92), respectively. Conclusions: Cognition partially improved in patients with OSAS after CPAP treatment. The only domain with significant improvement was vigilance. Rigorous randomized controlled trials need to be performed to obtain clear results. PMID:26315086

  8. 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.

  9. 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

  10. The effect of short-term withdrawal from continuous positive airway pressure therapy on sympathetic activity and markers of vascular inflammation in subjects with obstructive sleep apnoea.

    PubMed

    Phillips, Craig L; Yang, Qiao; Williams, Andrew; Roth, Michael; Yee, Brendon J; Hedner, Jan A; Berend, Norbert; Grunstein, Ronald R

    2007-06-01

    Obstructive sleep apnoea (OSA) is commonly associated with cardiovascular disease and sympathetic activation. However, it is unclear whether this association is independent of obesity and to what extent treatment with nasal continuous positive airway pressure (CPAP) alleviates the vascular inflammation that underpins cardiovascular disease. We therefore evaluated whether short-term withdrawal from CPAP therapy in subjects with moderate-severe OSA would result in increased levels of sympathetic activity and circulating inflammatory cytokines independent of weight. Vascular inflammatory markers (hsCRP, hsIL-6 and hsTNF-alpha) were assessed in 20 subjects after one and seven nights of withdrawal from CPAP together with the hypoxia-responsive angiogenic marker VEGF and urinary catecholamines. Compared with baseline on CPAP, withdrawal from therapy resulted in an immediate return of OSA with an increase in RDI to 26.7 +/- 5.2 and 39.0 +/- 5.9 events per hour after one and seven nights without CPAP, respectively (both P < 0.0001). This was accompanied by a concomitant rise in daytime urinary noradrenaline (P < 0.0001) after seven nights CPAP withdrawal that was positively associated with the severity of hypoxaemia. In contrast, withdrawal from CPAP therapy was not accompanied by any change in measured cytokines or VEGF (all P > 0.1). In conclusion, 1 week of CPAP withdrawal was associated with a return of OSA and a marked increase in sympathetic activity without a concomitant elevation of vascular inflammatory markers.

  11. Efficacy of continuous positive airway pressure treatment on 5-year survival in patients with ischaemic stroke and obstructive sleep apnea: a randomized controlled trial.

    PubMed

    Parra, Olga; Sánchez-Armengol, Ángeles; Capote, Francisco; Bonnin, Marc; Arboix, Adrià; Campos-Rodríguez, Francisco; Pérez-Ronchel, José; Durán-Cantolla, Joaquín; Martínez-Null, Cristina; de la Peña, Mónica; Jiménez, Maria Carmen; Masa, Fernando; Casadon, Ignacio; Alonso, Maria Luz; Macarrón, José L

    2015-02-01

    The main purpose of the present analysis is to assess the influence of introducing early nasal continuous positive airway pressure (nCPAP) treatment on cardiovascular recurrences and mortality in patients with a first-ever ischaemic stroke and moderate-severe obstructive sleep apnea (OSA) with an apnea-hypopnea index (AHI) ≥20 events h(-1) during a 5-year follow-up. Patients received conventional treatment for stroke and were assigned randomly to the nCPAP group (n = 71) or the control group (n = 69). Cardiovascular events and mortality were registered for all patients. Survival and cardiovascular event-free survival analysis were performed after 5-year follow-up using the Kaplan-Meier test. Patients in the nCPAP group had significantly higher cardiovascular survival than the control group (100 versus 89.9%, log-rank test 5.887; P = 0.015) However, and also despite a positive tendency, there were no significant differences in the cardiovascular event-free survival at 68 months between the nCPAP and control groups (89.5 versus 75.4%, log-rank test 3.565; P = 0.059). Early nCPAP therapy has a positive effect on long-term survival in ischaemic stroke patients and moderate-severe OSA.

  12. Effects of nasal mask leak and heated humidification on nasal mucosa in the therapy with nasal continuous positive airway pressure (nCPAP).

    PubMed

    Fischer, Yvonne; Keck, Tilman; Leiacker, Richard; Rozsasi, Ajnacska; Rettinger, Gerhard; Gruen, Philipp M

    2008-11-01

    The purpose of this study was to determine the objective short-term influence of nasal continuous positive airway pressure (nCPAP) therapy, nasal mask leak (NML) and heated humidifiers (HH) to nasal conditioning of spontaneously breathing subjects. This was a prospective, non-randomized, non-blinded day-time study. Eighteen healthy subjects were enrolled in the study. All subjects received nCPAP therapy for 60 min in three different conditions successively: (1) nCPAP without humidification, (2) nCPAP with a defined leakage of nasal mask (slashed circle 28.3 mm2) and (3) nCPAP with HH. Nasal humidity and temperature were measured in the anterior turbinate area using a miniaturized thermocouple and a relative humidity sensor. The measurements were accomplished at the beginning of therapy, after 60, 120 and 180 min. Absolute humidity (aH) in the anterior turbinate area decreased significantly (p = 0.0075) from 17.41 +/- 3.81 mg/l (baseline) to 15.27 +/- 2.21 mg/l (nCPAP alone). With attachment of a NML, aH decreased from 15.27 mg/l not significantly (p = 0.058) to 13.77 +/- 2.28 mg/l (nCPAP and NML) compared to nCPAP alone. After addition of heated humidification to nCPAP, aH increased again from 13.77 mg/l significantly (p = 0.042) to 15.29 +/- 3.51 mg/l (nCPAP and HH) compared to aH (nCPAP+NML). No difference was found between aH (nCPAP and HH) and aH (nCPAP alone). Airway temperature did not change significantly after application of nCPAP alone, nCPAP and NML, and nCPAP and HH. These data indicate that nCPAP therapy with NML tends to have more remarkable reduction of the nasal humidity than nCPAP therapy without NML. nCPAP with heated humidifier is able to compensate the dehydration effects induced by nCPAP therapy with NML by increasing the aH at the anterior turbinate area to the levels observed during breathing with nCPAP alone.

  13. Estimation of airway obstruction using oximeter plethysmograph waveform data

    PubMed Central

    Arnold, Donald H; Spiro, David M; Desmond, Renee' A; Hagood, James S

    2005-01-01

    Background Validated measures to assess the severity of airway obstruction in patients with obstructive airway disease are limited. Changes in the pulse oximeter plethysmograph waveform represent fluctuations in arterial flow. Analysis of these fluctuations might be useful clinically if they represent physiologic perturbations resulting from airway obstruction. We tested the hypothesis that the severity of airway obstruction could be estimated using plethysmograph waveform data. Methods Using a closed airway circuit with adjustable inspiratory and expiratory pressure relief valves, airway obstruction was induced in a prospective convenience sample of 31 healthy adult subjects. Maximal change in airway pressure at the mouthpiece was used as a surrogate measure of the degree of obstruction applied. Plethysmograph waveform data and mouthpiece airway pressure were acquired for 60 seconds at increasing levels of inspiratory and expiratory obstruction. At each level of applied obstruction, mean values for maximal change in waveform area under the curve and height as well as maximal change in mouth pressure were calculated for sequential 7.5 second intervals. Correlations of these waveform variables with mouth pressure values were then performed to determine if the magnitude of changes in these variables indicates the severity of airway obstruction. Results There were significant relationships between maximal change in area under the curve (P < .0001) or height (P < 0.0001) and mouth pressure. Conclusion The findings suggest that mathematic interpretation of plethysmograph waveform data may estimate the severity of airway obstruction and be of clinical utility in objective assessment of patients with obstructive airway diseases. PMID:15985171

  14. Negative pressure wound therapy for Gustilo Anderson grade IIIb open tibial fractures

    PubMed Central

    Park, Chul Hyun; Shon, Oog Jin; Kim, Gi Beom

    2016-01-01

    Background: Traditionally, Gustilo Anderson grade IIIb open tibial fractures have been treated by initial wide wound debridement, stabilization of fracture with external fixation, and delayed wound closure. The purpose of this study is to evaluate the clinical and radiological results of staged treatment using negative pressure wound therapy (NPWT) for Gustilo Anderson grade IIIb open tibial fractures. Materials and Methods: 15 patients with Gustilo Anderson grade IIIb open tibial fractures, treated using staged protocol by a single surgeon between January 2007 and December 2011 were reviewed in this retrospective study. The clinical results were assessed using a Puno scoring system for severe open fractures of the tibia at the last followup. The range of motion (ROM) of the knee and ankle joints and postoperative complication were evaluated at the last followup. The radiographic results were assessed using time to bone union, coronal and sagittal angulations and a shortening at the last followup. Results: The mean score of Puno scoring system was 87.4 (range 67–94). The mean ROM of the knee and ankle joints was 121.3° (range 90°–130°) and 37.7° (range 15°–50°), respectively. Bone union developed in all patients and the mean time to union was 25.3 weeks (range 16–42 weeks). The mean coronal angulation was 2.1° (range 0–4°) and sagittal was 2.7° (range 1–4°). The mean shortening was 4.1 mm (range 0–8 mm). Three patients had partial flap necrosis and 1 patient had total flap necrosis. There was no superficial and deep wound infection. Conclusion: Staged treatment using NPWT decreased the risks of infection and requirement of flap surgeries in Gustilo Anderson grade IIIb open tibial fractures. Therefore, staged treatment using NPWT could be a useful treatment option for Gustilo Anderson grade IIIb open tibial fractures. PMID:27746498

  15. Optimal optic nerve sheath diameter threshold for the identification of elevated opening pressure on lumbar puncture in a Chinese population.

    PubMed

    Wang, Lijuan; Feng, Liangshu; Yao, Yan; Wang, Yuzhi; Chen, Ying; Feng, Jiachun; Xing, Yingqi

    2015-01-01

    Ultrasonography of the optic nerve sheath diameter (ONSD) is a non-invasive and rapid method that might be helpful in the identification of increased intracranial pressure (ICP). The use of an ONSD greater than 5 mm on ultrasound as an indicator of increased ICP in a Caucasian population has been studied. However, the cut-off point of this predictor in Chinese patients has not been established. Thus, we conducted this study to identify the ONSD criterion for the detection of elevated opening pressure on lumbar puncture (LP) in a Chinese population and to investigate the influencing factors. This study was a blind cross-sectional study. Patients who presented with suspected increased ICP were included. The opening pressure on LP of each participant was confirmed. We analyzed the clinical differences between the groups of patients with abnormal and normal opening pressures on LP. A receiver operating characteristic curve was constructed to determine the ONSD cut-off point for the identification of abnormal opening pressure on LP. In total, 279 patients were recruited, and 101 patients presented with elevated opening pressure on LP. ONSD was a significant independent predictor of elevated opening pressure on LP (p<0.001). However, no statistical significance was observed regarding the factors that might have affected this relationship including gender, age, body mass index, waistline, head circumference, hypertension and pathological subtype. The ONSD cut-off point for the identification of elevated opening pressure on LP was 4.1 mm; this cut-off yielded a sensitivity of 95% and a specificity of 92%. ONSD is a strong and accurate predictor of elevated opening pressure on LP. The cut-off point of this predictor in a Chinese population was remarkably lower than that found in a Caucasian population. Thus, ethnic differences should be noted when using the ONSD as an indicator of increased ICP.

  16. The Phillips airway.

    PubMed

    Haridas, R P; Wilkinson, D J

    2012-07-01

    The Phillips airway was developed by George Ramsay Phillips. There is no known original description of the airway and the earliest known reference to it is from 1919. The airway and its modifications are described.

  17. Low pressure drop filtration of airborne molecular organic contaminants using open-channel networks

    NASA Astrophysics Data System (ADS)

    Dallas, Andrew J.; Joriman, Jon; Ding, Lefei; Weineck, Gerald; Seguin, Kevin

    2007-03-01

    Airborne molecular contamination (AMC) continues to play a very decisive role in the performance of many microelectronic devices and manufacturing processes. Besides airborne acids and bases, airborne organic contaminants such as 1-methyl-2-pyrrolidinone (NMP), hexamethyldisiloxane (HMDSO), trimethylsilanol (TMS), perfluoroalkylamines and condensables are of primary concern in these applications. Currently, the state of the filtration industry is such that optimum filter life and removal efficiency for organics is offered by granular carbon filter beds. However, the attributes that make packed beds of activated carbon extremely efficient also impart issues related to elevated filter weight and pressure drop. Most of the lower pressure drop AMC filters currently offered are quite expensive and are simply pleated combinations of various adsorptive and reactive media. On the other hand, low pressure drop filters, such as those designed as open-channel networks (OCN's), offer good filter life and removal efficiency with the additional benefits of significant reductions in overall filter weight and pressure drop. Equally important for many applications, the OCN filters can reconstruct the airflow so as to enhance the operation of a tool or process. For tool mount assemblies and fan filter units (FFUs) this can result in reduced fan and blower speeds, which subsequently can provide reduced vibration and energy costs. Additionally, these low pressure drop designs can provide a cost effective way of effectively removing AMC in full fab (or HVAC) filtration applications without significantly affecting air-handling requirements. Herein, we will present a new generation of low pressure drop OCN filters designed for the removal of airborne organics in a wide range of applications.

  18. Numerical study of pressure fluctuations in different guide vanes' opening angle in pump mode of a pump turbine

    NASA Astrophysics Data System (ADS)

    Sun, Y. K.; Zuo, Z. G.; Liu, S. H.; Liu, J. T.; Wu, Y. L.

    2012-11-01

    A numerical model based on a pumped storage power station was built to develop the numerical simulation, to analyze the pressure fluctuations in a pump turbine in different guide vanes' opening angle. The different guide vanes' opening angles were simulated using the SST k-ω turbulence model and SIMPLEC Pressure-Velocity coupling scheme. The pressure sensor were placed in mainly three positions, they are: bottom ring between runner and the wicket gates, downstream and left side in the draft tube cone below the runner. All the peak to peak values of pressure fluctuation meet signal probability of 97%. The frequency is gained by Fast Fourier Transform. The pressure fluctuations in different positions of the model in pump condition were showed when the guide vanes' opening angels were different. The simulation results confirmed the results gained in model tests. The results show that pressure fluctuations in design opening angle were much lower than those in off design opening angle. The main source of pressure fluctuations between runner and guide vanes is rotor stator interaction. While a lower frequency is the main frequency of the pressure fluctuation in draft tube.

  19. [The effect of crystalline lens extraction on intraocular pressure in patients with primary open-angle glaucoma].

    PubMed

    Macarie, S; Macarie, Daniela

    2013-01-01

    This issue presents the results of a study on patients with cataract and primary open angle glaucoma who suffered lens extraction for cataract. We analise the effects of the lens extraction on the level of intraocular pressure at this patients.

  20. Blockage of upper airway

    MedlinePlus

    ... Airway obstruction - acute upper Images Throat anatomy Choking Respiratory system References Cukor J, Manno M. Pediatric respiratory emergencies: upper airway obstruction and infections. In: Marx ...

  1. The Effects of Massage with Coconut and Sunflower Oils on Oxygen Saturation of Premature Infants with Respiratory Distress Syndrome Treated With Nasal Continuous Positive Airway Pressure

    PubMed Central

    Valizadeh, Sousan; Hosseini, Mohammad Bagher; Asghari Jafarabadi, Mohammad; Ajoodanian, Najmeh

    2012-01-01

    Introduction: Nowadays particular emphasis is placed on the developmental aspects of premature infants care. Massage therapy is one of the best-known methods of caring. Due to the minimal touch policy in neonatal intensive care units (NICUs), massaging is not usually performed on premature infants. However, there is not sufficient evidence to support the claim that newborn infants with complex medical conditions should not be massaged. This study aimed to determine the effects of massage with coconut and sunflower oils on oxygen saturation of infants with respiratory distress syndrome (RDS) treated with nasal continuous positive airway pressure (NCPAP). Methods: This was a randomized controlled trial on 90 newborns who were admitted to Alzahra Hospital (Tabriz, Iran). The infants were divided into control and massage therapy groups (massage with coconut and sunflower oils). Data was collected using a hospital documentation form. A 15-minute daily massage was performed for 3 days. Respiratory rate (RR), fraction of inspired oxygen (FiO2) and oxygen saturation were measured 5 minutes before the massage, 3 times during the massage, and 5 minutes after the massage. The collected data was analyzed using a mixed model. Results: In comparison to coconut oil and control groups, mean oxygen saturation of sunflower oil group was improved. In addition, the coconut massage group showed lower oxygen saturation than the control group but was all values were within the normal range. Although massage decreased oxygen saturation, there was no need to increase FiO2. Conclusion: Massage therapy can provide developmental care for infants treated with NCPAP. PMID:25276695

  2. Randomised controlled comparison of continuous positive airways pressure, bilevel non-invasive ventilation, and standard treatment in emergency department patients with acute cardiogenic pulmonary oedema

    PubMed Central

    Crane, S; Elliott, M; Gilligan, P; Richards, K; Gray, A

    2004-01-01

    Background: Continuous positive airways pressure (CPAP) and bilevel non-invasive ventilation may have beneficial effects in the treatment of patients with acute cardiogenic pulmonary oedema. The efficacy of both treatments was assessed in the UK emergency department setting, in a randomised comparison with standard oxygen therapy. Methods: Sixty patients presenting with acidotic (pH<7.35) acute, cardiogenic pulmonary oedema, were randomly assigned conventional oxygen therapy, CPAP (10 cm H2O), or bilevel ventilation (IPAP 15 cm H2O, EPAP 5 cm H2O) provided by a standard ventilator through a face mask. The main end points were treatment success at two hours and in-hospital mortality. Analyses were by intention to treat. Results: Treatment success (defined as all of respiratory rate<23 bpm, oxygen saturation of>90%, and arterial blood pH>7.35 (that is, reversal of acidosis), at the end of the two hour study period) occurred in three (15%) patients in the control group, seven (35%) in the CPAP group, and nine (45%) in the bilevel group (p = 0.116). Fourteen (70%) of the control group patients survived to hospital discharge, compared with 20 (100%) in the CPAP group and 15 (75%) in the bilevel group (p = 0.029; Fisher's test). Conclusions: In this study, patients presenting with acute cardiogenic pulmonary oedema and acidosis, were more likely to survive to hospital discharge if treated with CPAP, rather than with bilevel ventilation or with conventional oxygen therapy. There was no relation between in hospital survival and early physiological changes. Survival rates were similar to other studies despite a low rate of endotracheal intubation. PMID:14988338

  3. Postoperative pharyngolaryngeal adverse events with laryngeal mask airway (LMA Supreme) in laparoscopic surgical procedures with cuff pressure limiting 25 cmH₂O: prospective, blind, and randomised study.

    PubMed

    Kang, Joo-Eun; Oh, Chung-Sik; Choi, Jae Won; Son, Il Soon; Kim, Seong-Hyop

    2014-01-01

    To reduce the incidence of postoperative pharyngolaryngeal adverse events, laryngeal mask airway (LMA) manufacturers recommend maximum cuff pressures not exceeding 60 cmH₂O. We performed a prospective randomised study, comparing efficacy and adverse events among patients undergoing laparoscopic surgical procedures who were allocated randomly into low (limiting 25 cmH₂O, L group) and high (at 60 cmH₂O, H group) LMA cuff pressure groups with LMA Supreme. Postoperative pharyngolaryngeal adverse events were evaluated at discharge from postanaesthetic care unit (PACU) (postoperative day 1, POD 1) and 24 hours after discharge from PACU (postoperative day 2, POD 2). All patients were well tolerated with LMA without ventilation failure. Before pneumoperitoneum, cuff volume and pressure and oropharyngeal leak pressure (OLP) showed significant differences. Postoperative sore throat at POD 2 (3 versus 12 patients) and postoperative dysphagia at POD 1 and POD 2 (0 versus 4 patients at POD 1; 0 versus 4 patients at POD 2) were significantly lower in L group, compared with H group. In conclusion, LMA with cuff pressure limiting 25 cmH₂O allowed both efficacy of airway management and lower incidence of postoperative adverse events in laparoscopic surgical procedures. This clinical trial is registered with KCT0000334.

  4. The open abdomen: temporary closure with a modified negative pressure therapy technique.

    PubMed

    Hougaard, Helene T; Ellebaek, Mark; Holst, Uffe T; Qvist, Niels

    2014-06-01

    The most common indications for an open abdomen (OA) are abdominal compartment syndrome, damage control surgery, diffuse peritonitis and wound dehiscence, and often require a temporary abdominal closure (TAC). The different TAC methods that are currently available include skin closure techniques, mesh products and negative pressure therapy (NPT) systems. For this study, we retrospectively reviewed records of 115 OA patients treated with the commercially available NPT systems (V.A.C.(®) Abdominal Dressing System and ABThera™ Open Abdomen Negative Pressure Therapy System) using a new method of applying the system - the narrowing technique - over a 5-year period. Endpoints included fascial closure and 30-day mortality rates and presence of enteroatmospheric fistulas. Secondary closure of the fascia was obtained in 92% (106/115) of the patients with a mortality rate of 17% (20/115) and a fistula rate of 3·5% (4/115). The use of the narrowing technique to apply NPT may explain the high closure rates observed in the patient population of this study. Further studies are necessary to compare the different methods and to evaluate the long-term outcomes.

  5. Negative pressure wound therapy with reticulated open cell foam in children: an overview.

    PubMed

    Contractor, Dhruti; Amling, June; Brandoli, Cinzia; Tosi, Laura L

    2008-01-01

    This article summarizes the results of a comprehensive review of the literature on the use of negative pressure wound therapy with reticulated open cell foam (NPWT/ROCF) as delivered by V.A.C.(R) Therapy (KCI, San Antonio, TX) in pediatric patients. A review of the literature revealed 20 articles that discussed the use of NPWT/ROCF in exclusively pediatric patients. Nine articles were retrospective reviews, and 11 were case studies. This review discusses the insights from these articles. This review discusses the versatility of NPWT/ROCF for use with pediatric patients with infected wounds; full-thickness burns; open fractures; large soft tissue wounds; surgical wounds of the chest, abdomen, and spine; pilonidal disease; and pressure ulcers. NPWT/ROCF has been used in children as young as a few weeks of age, and in children with comorbidities such as congenital heart disease, immunosuppression, and spina bifida. Wound healing in children can be delayed by impaired perfusion, infection, edema, and poor nutrition. Clinical considerations for using NPWT/ROCF in children can include differences in healing due to higher granulation rates requiring more frequent dressing changes, poor nutritional status, small size, and low weight. With pediatric patients, there is no consensus on foam (white or black) selection, optimum amount of negative pressure, frequency of NPWT/ROCF dressing changes, and interposing contact layer selection. Randomized prospective studies are needed to make recommendations for safe and efficacious clinical practice. Research regarding the effects of dressing types, adjunctive treatment, and wound healing in neonates and children is needed.

  6. Literature review and meta-analysis of translaminar pressure difference in open-angle glaucoma

    PubMed Central

    Siaudvytyte, L; Januleviciene, I; Daveckaite, A; Ragauskas, A; Bartusis, L; Kucinoviene, J; Siesky, B; Harris, A

    2015-01-01

    There is increasing evidence in the literature regarding translaminar pressure difference's (TPD) role in the pathophysiology of glaucoma. The optic nerve is exposed not only to intraocular pressure in the eye, but also to intracranial pressure (ICP), as it is surrounded by cerebrospinal fluid in the subarachnoid space. Although pilot studies have identified the potential importance of TPD in glaucoma, limited available data currently prevent a comprehensive description of the role that TPD may have in glaucomatous pathophysiology. In this review, we present all available qualified data from a systematic review of the literature of the role of TPD in open-angle glaucoma (OAG). PubMed (Medline), OVID Medline, ScienceDirect, SpringerLink, and all available library databases were reviewed and subsequent meta-analysis of pooled mean differences are presented where appropriate. Five papers including 396 patients met criteria for inclusion to the analysis. Importantly, we included all observational studies despite differences in ICP measurement methods, as there is no consensus regarding best-practice ICP measurements in glaucoma. Our results show that not only TPD is higher in glaucoma patients compared with healthy subjects, it is related to structural glaucomatous changes of the optic disc. Our analysis suggests further longitudinal prospective studies are needed to investigate the influence of TPD in OAG, with a goal of overcoming methodological weaknesses of previous studies. PMID:26183286

  7. Literature review and meta-analysis of translaminar pressure difference in open-angle glaucoma.

    PubMed

    Siaudvytyte, L; Januleviciene, I; Daveckaite, A; Ragauskas, A; Bartusis, L; Kucinoviene, J; Siesky, B; Harris, A

    2015-10-01

    There is increasing evidence in the literature regarding translaminar pressure difference's (TPD) role in the pathophysiology of glaucoma. The optic nerve is exposed not only to intraocular pressure in the eye, but also to intracranial pressure (ICP), as it is surrounded by cerebrospinal fluid in the subarachnoid space. Although pilot studies have identified the potential importance of TPD in glaucoma, limited available data currently prevent a comprehensive description of the role that TPD may have in glaucomatous pathophysiology. In this review, we present all available qualified data from a systematic review of the literature of the role of TPD in open-angle glaucoma (OAG). PubMed (Medline), OVID Medline, ScienceDirect, SpringerLink, and all available library databases were reviewed and subsequent meta-analysis of pooled mean differences are presented where appropriate. Five papers including 396 patients met criteria for inclusion to the analysis. Importantly, we included all observational studies despite differences in ICP measurement methods, as there is no consensus regarding best-practice ICP measurements in glaucoma. Our results show that not only TPD is higher in glaucoma patients compared with healthy subjects, it is related to structural glaucomatous changes of the optic disc. Our analysis suggests further longitudinal prospective studies are needed to investigate the influence of TPD in OAG, with a goal of overcoming methodological weaknesses of previous studies.

  8. Measurements of Pressure Distributions and Force Coefficients in a Squeeze Film Damper. Part 1: Fully Open Ended Configuration

    NASA Technical Reports Server (NTRS)

    Jung, S. Y.; Sanandres, Luis A.; Vance, J. M.

    1991-01-01

    Measurements of pressure distributions and force coefficients were carried out in two types of squeeze film dampers, executing a circular centered orbit, an open-ended configuration, and a partially sealed one, in order to investigate the effect of fluid inertia and cavitation on pressure distributions and force coefficients. Dynamic pressure measurements were carried out for two orbit radii, epsilon 0.5 and 0.8. It was found that the partially sealed configuration was less influenced by fluid inertia than the open ended configuration.

  9. Airway management in emergency situations.

    PubMed

    Dörges, Volker

    2005-12-01

    Securing and monitoring the airway are among the key requirements of appropriate therapy in emergency patients. Failures to secure the airways can drastically increase morbidity and mortality of patients within a very short time. Therefore, the entire range of measures needed to secure the airway in an emergency, without intermediate ventilation and oxygenation, is limited to 30-40 seconds. Endotracheal intubation is often called the 'gold standard' for airway management in an emergency, but multiple failed intubation attempts do not result in maintaining oxygenation; instead, they endanger the patient by prolonging hypoxia and causing additional trauma to the upper airways. Thus, knowledge and availability of alternative procedures are also essential in every emergency setting. Given the great variety of techniques available, it is important to establish a well-planned, methodical protocol within the framework of an algorithm. This not only facilitates the preparation of equipment and the training of personnel, it also ensures efficient decision-making under time pressure. Most anaesthesia-related deaths are due to hypoxaemia when difficulty in securing the airway is encountered, especially in obstetrics during induction of anaesthesia for caesarean delivery. The most commonly occurring adverse respiratory events are failure to intubate, failure to recognize oesophageal intubation, and failure to ventilate. Thus, it is essential that every anaesthesiologist working on the labour and delivery ward is comfortable with the algorithm for the management of failed intubation. The algorithm for emergency airway management describing the sequence of various procedures has to be adapted to internal standards and to techniques that are available.

  10. Suppression of pressure oscillations in an open cavity by passive pneumatic control

    NASA Technical Reports Server (NTRS)

    Chokani, N.; Kim, I.

    1991-01-01

    A computational investigation has been conducted to determine the effectiveness of a passive control technique in suppressing the oscillations in an open cavity exposed to a supersonic flow. Time-accurate solutions of the unsteady, Reynolds-averaged, Navier-Stokes equations were obtained with an explicit predictor-corrector algorithm; the passive control was implemented through the use of a simple linear pressure-velocity law along the porous cavity floor. The computational code was validated by comparisons with experimental data for the cavity flow without control. The computational results with control demonstrate that the oscillations are suppressed; the fluid dynamic mechanism of the control is seen to be a stabilization of the free-shear layer. Spectral analysis of the unsteady data shows that the resonant frequencies are essentially unchanged by the control. Beneficial reductions in the cavity resonant drag are also observed.

  11. Anthropogenic pressure on the open ocean: The growth of ship traffic revealed by altimeter data analysis

    NASA Astrophysics Data System (ADS)

    Tournadre, J.

    2014-11-01

    Marine ecosystems are under increasing anthropogenic pressures from marine and terrestrial activities. Ship traffic, the major cause of change in the open ocean, and its temporal evolution are still largely unknown because of lack of data. Altimeter data provide a new powerful tool to detect and monitor the ship traffic through a method of analysis of echo waveform. The archive of seven altimeter missions has been processed to create a two decade database of ship locations. The estimated annual density maps compare well with the ones obtained from Automatic Identification System. The ship traffic analysis shows a global fourfold growth between 1992 and 2012, the largest increase being observed in the Indian Ocean and the Chinese seas reflecting the world trade change. Although mainly concentrated along lanes, the traffic has a direct impact on the atmosphere, e.g., on the growth of tropospheric nitrogen dioxide in the Indian Ocean.

  12. Open hole packer for high pressure service in a five hundred degree fahrenheit precambrian wellbore

    SciTech Connect

    Dreesen, D.S.; Miller, J.R.; Halbardier, F.A.; Nicholson, R.W.

    1985-01-01

    Massive hydraulic fracturing (MHF) from a lower wellbore (EE-2) created a large man-made reservoir which did not intersect the upper well (EE-3). To create a heat extraction flow loop, the upper well was sidetracked and redrilled (EE-3A) down into a microseismic cloud around EE-2 mapped during the MHF. The potential to intersect numerous fracture zones in the redrilled bore was apparent from seismicity. To economically and effectively isolate and test these microseismic zones required that a functional open hole packer be developed. The packer would be exposed to soak temperatures as high as 500/sup 0/F (260/sup 0/C) with cool down to 100/sup 0/F (40/sup 0/C) at differential pressures exceeding 5000 psi (35 Mpa). A functional packer has been designed, manufactured, and successfully used for the creation of a hot dry rock (HDR) reservoir. 5 figs., 1 tab.

  13. Ventilation of Nonparalyzed Patients Under Anesthesia with Laryngeal Mask Airway, Comparison of Three Modes of Ventilation: Volume Controlled Ventilation, Pressure Controlled Ventilation, and Pressure Controlled Ventilation-volume Guarantee

    PubMed Central

    Ghabach, Maroun Badwi; El Hajj, Elie M.; El Dib, Rouba D.; Rkaiby, Jeanette M.; Matta, May S.; Helou, May R.

    2017-01-01

    Background: Pressure controlled ventilation (PCV) is the preferable mode of ventilation of nonparalyzed patients undergoing anesthesia with laryngeal mask airway (LMA) as compared to volume controlled ventilation (VCV) and spontaneously breathing patient. In this study, we compared the PC–volume guarantee (PC-VG) mode of ventilation with VCV and PCV modes. Materials and Methods: A total of 30 patients, American Society of Anesthesiologists (ASA) physical status Classes I and II, scheduled for elective surgery under general anesthesia with a classic LMA were ventilated, subsequently, with the three modes of ventilation: VCV, PCV, and PC-VG for 10 min each mode. Tidal volume set for all patients was 8 ml/kg of ideal body weight. Parameters measured with modes of ventilation include peak inspiratory pressure (PIP), compliance, measured tidal volume, O2 saturation, end-tidal CO2, and presence of an oropharyngeal leak. Results: The PIP was significantly higher with the application of VCV mode of ventilation than PCV and PC-VG modes. The compliance was significantly lower when using the mode of ventilation VCV than PCV and PC-VG. The PIP and the compliance were not statistically different between the PCV and PC-VG modes of ventilation. Conclusions: Ventilation of nonparalyzed patients with LMA under anesthesia with PC-VG is advantageous over VCV in reducing PIP and increasing lung compliance. No difference was noted between PCV and PC-VG in ASA Classes I or II under the adequate depth of anesthesia in patients with normal pulmonary function. PMID:28298784

  14. Continuous Positive Airway Pressure (CPAP)

    MedlinePlus

    ... Copyright © 2017 American Academy of Otolaryngology–Head and Neck Surgery. Reproduction or republication strictly prohibited without prior written ... Copyright 2017. American Academy of Otolaryngology — Head and Neck Surgery 1650 Diagonal Rd Alexandria, VA 22314 tel (703) ...

  15. Effect of Continuous Positive Airway Pressure Therapy on Glycemic Excursions and Insulin Sensitivity in Patients with Obstructive Sleep Apnea-hypopnea Syndrome and Type 2 Diabetes

    PubMed Central

    Guo, Li-Xin; Zhao, Xin; Pan, Qi; Sun, Xue; Li, Hui; Wang, Xiao-Xia; Zhang, Li-Na; Wang, Yao

    2015-01-01

    Background: For patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) and type 2 diabetes mellitus (T2DM), the night sleep interruption and intermittent hypoxia due to apnea or hypopnea may induce glycemic excursions and reduce insulin sensitivity. This study aimed to investigate the effect of continuous positive airway pressure (CPAP) therapy in patients with OSAHS and T2DM. Methods: Continuous glucose monitoring system (CGMS) was used in 40 patients with T2DM and newly diagnosed OSAHS. The measurements were repeated after 30 days of CPAP treatment. Subsequently, insulin sensitivity and glycohemoglobin (HbA1c) were measured and compared to the pretreatment data. Results: After CPAP therapy, the CGMS indicators showed that the 24-h mean blood glucose (MBG) and the night time MBG were significantly reduced (P < 0.05 and P = 0.03, respectively). The mean ambulatory glucose excursions (MAGEs) and the mean of daily differences were also significantly reduced (P < 0.05 and P = 0.002, respectively) compared to pretreatment levels. During the night, MAGE also significantly decreased (P = 0.049). The differences between the highest and lowest levels of blood glucose over 24 h and during the night were significantly lower than prior to CPAP treatment (P < 0.05 and P = 0.024, respectively). The 24 h and night time durations of high blood glucose (>7.8 mmol/L and > 11.1 mmol/L) decreased (P < 0.05 and P < 0.05, respectively) after the treatment. In addition, HbA1c levels were also lower than those before treatment (P < 0.05), and the homeostasis model assessment index of insulin resistance was also significantly lower than before CPAP treatment (P = 0.034). Conclusions: CPAP therapy may have a beneficial effect on improving not only blood glucose but also upon insulin sensitivity in T2DM patients with OSAHS. This suggests that CPAP may be an effective treatment for T2DM in addition to intensive diabetes management. PMID:26315076

  16. Crack opening area estimates in pressurized through-wall cracked elbows under bending

    SciTech Connect

    Franco, C.; Gilles, P.; Pignol, M.

    1997-04-01

    One of the most important aspects in the leak-before-break approach is the estimation of the crack opening area corresponding to potential through-wall cracks at critical locations during plant operation. In order to provide a reasonable lower bound to the leak area under such loading conditions, numerous experimental and numerical programs have been developed in USA, U.K. and FRG and widely discussed in literature. This paper aims to extend these investigations on a class of pipe elbows characteristic of PWR main coolant piping. The paper is divided in three main parts. First, a new simplified estimation scheme for leakage area is described, based on the reference stress method. This approach mainly developed in U.K. and more recently in France provides a convenient way to account for the non-linear behavior of the material. Second, the method is carried out for circumferential through-wall cracks located in PWR elbows subjected to internal pressure. Finite element crack area results are presented and comparisons are made with our predictions. Finally, in the third part, the discussion is extended to elbows under combined pressure and in plane bending moment.

  17. Triggers of airway inflammation.

    PubMed

    Kerrebijn, K F

    1986-01-01

    Most asthmatics have hyperresponsive airways. This makes them more sensitive than non-asthmatics to bronchoconstricting environmental exposures which, in their turn, may enhance responsiveness. Airway inflammation is considered to be a key determinant of airway hyperresponsiveness: the fact that chronic airway inflammation in cystic fibrosis does not lead to airway hyperresponsiveness of any importance indicates, however, that the role of airway inflammation is complex and incompletely elucidated. The main inducers of airway inflammation are viral infections, antigens, occupational stimuli and pollutants. Although exercise, airway cooling and hyper- or hypotonic aerosols are potent stimuli of bronchoconstriction, it is questionable if airway inflammation is involved in their mode of action. Each of the above-mentioned stimuli is discussed, with emphasis laid on the relation of symptoms to mechanisms.

  18. Continuous positive airway pressure for sleep apnoea/hypopnoea syndrome: usefulness of a 2 week trial to identify factors associated with long term use

    PubMed Central

    Popescu, G; Latham, M; Allgar, V; Elliott, M

    2001-01-01

    BACKGROUND—The sleep apnoea/hypopnoea syndrome (SAHS) is common and treatment with continuous positive airway pressure (CPAP) is effective. However, not all patients can cope with the demands of using mask positive pressure. Compliance can be improved with an intensive educational programme and patient support, but this is not practical in most centres given the large numbers of patients coming forward for treatment. Several studies have evaluated correlations between various parameters at diagnosis in order to anticipate patients' behaviour and to avoid the social and health implications of undertreated SAHS. We have evaluated the use of additional data derived during a 2 week home CPAP trial to identify factors associated with longer term use of CPAP and compliance.
METHODS—Following a diagnostic study, 209 patients were offered a CPAP machine for a 2 week home trial. After completing the trial, patients were reassessed and scored their overall satisfaction with CPAP treatment on a five point scale ranging from "much worse" to "much better" and an Epworth score relating to the loan period. Machine run time was recorded from the integral clock. These data were added to those available at diagnosis to construct models indicative of continuing CPAP and average nightly use at 1year.
RESULTS—209 patients were offered the 2 week loan at least a year before June 1999 (90.9% men, mean (SD) age 51.0 (10.6) years, body mass index (BMI) 34.6 (7.7) kg/m2, Epworth score 15 (IQR 11-18), apnoea/hypopnoea index (AHI) 38.1(22.9) events/h). 153 patients (73.2%) opted to continue CPAP and 56 declined. One year later data were available for 187 patients; 128 (68.5% on an intention to treat analysis) continued to use the machine with a mean use of 5.0 (2.4) hours/night. A logistic regression model indicated that mean CPAP use during the loan period and the overall satisfaction score accurately defined continuing CPAP and "satisfactory" CPAP use at 1 year. For patients with

  19. Combination of negative pressure wound therapy with open bone grafting for bone and soft tissue defects.

    PubMed

    Deng, Kai; Yu, Ai-Xi; Xia, Cheng-Yan; Li, Zong-Huan; Wang, Wei-Yang

    2013-08-01

    The aim of this study was to investigate the efficiency of negative pressure wound therapy (NPWT) combined with open bone graft (OBG; NPWT-OBG) for the treatment of bone and soft tissue defects with polluted wounds in an animal model. All rabbits with bone and soft tissue defects and polluted wounds were randomly divided into two groups, the experimental group (NPWT with bone graft) and the control group (OBG). The efficacy of the treatment was assessed by the wound conditions and healing time. Bacterial bioburdens and bony calluses were evaluated by bacteria counting and X-rays, respectively. Furthermore, granulation tissue samples from the wounds on days 0, 3, 7 and 14 of healing were evaluated for blood vessels and vascular endothelial growth factor (VEGF) levels. Wounds in the experimental group tended to have a shorter healing time, healthier wound conditions, lower bacterial bioburden, improvement of the bony calluses and an increased blood supply compared with those in the control group. With NPWT, wound infection was effectively controlled. For wounds with osseous and soft tissue defects, NPWT combined with bone grafting was demonstrated to be more effective than an OBG.

  20. Emergency airway puncture

    MedlinePlus

    ... support for only a very short period of time. Alternative Names Needle cricothyrotomy Images Emergency airway puncture Cricoid cartilage Emergency airway puncture - series References Hebert RB, Bose S, Mace SE. Cricothyrotomy and ...

  1. Upper airway biopsy

    MedlinePlus

    ... upper airway Images Upper airway test Bronchoscopy Throat anatomy References Yung RC, Boss EF. Tracheobronchial endoscopy. In: Flint PW, Haughey BH, Lund LJ, et al, eds. Cummings Otolaryngology: Head & Neck Surgery. 5th ed. Philadelphia, PA: Elsevier Mosby; ...

  2. The versatility of negative pressure wound therapy with reticulated open cell foam for soft tissue management after severe musculoskeletal trauma.

    PubMed

    Tarkin, Ivan S

    2008-01-01

    This review serves to outline the current and evolving usages of negative pressure wound therapy with reticulated open cell foam (NPWT/ROCF) as delivered by V.A.C.(R) Therapy (KCI, San Antonio, TX) as an adjunctive treatment modality for optimal management of wounds associated with high energy musculoskeletal trauma.

  3. Careers in Airway Science.

    ERIC Educational Resources Information Center

    Federal Aviation Administration (DOT), Washington, DC.

    The Federal Aviation Administration (FAA) has initiated the Airway Science curriculum as a method of preparing the next generation of aviation technicians and managers. This document: (1) discusses the FAA's role in the Airway Science program; (2) describes some of the career fields that FAA offers to Airway Science graduates (air traffic control…

  4. Airway blood flow response to dry air hyperventilation in sheep

    SciTech Connect

    Parsons, G.H.; Baile, E.M.; Pare, P.D.

    1986-03-01

    Airway blood flow (Qaw) may be important in conditioning inspired air. To determine the effect of eucapneic dry air hyperventilation (hv) on Qaw in sheep the authors studied 7 anesthetized open-chest sheep after 25 min. of warm dry air hv. During each period of hv the authors have recorded vascular pressures, cardiac output (CO), and tracheal mucosal and inspired air temperature. Using a modification of the reference flow technique radiolabelled microspheres were injected into the left atrium to make separate measurements after humid air and dry air hv. In 4 animals a snare around the left main pulmonary artery was used following microsphere injection to prevent recirculation (entry into L lung of microspheres from the pulmonary artery). Qaw to the trachea and L lung as measured and Qaw for the R lung was estimated. After the final injection the sheep were killed and bronchi (Br) and lungs removed. Qaw (trachea plus L lung plus R lung) in 4 sheep increased from a mean of 30.8 to 67.0 ml/min. Airway mucosal temp. decreased from 39/sup 0/ to 33/sup 0/C. The authors conclude that dry air hv cools airway mucosa and increases Qaw in sheep.

  5. Rapid, optical measurement of the atmospheric pressure on a fast research aircraft using open-path TDLAS

    NASA Astrophysics Data System (ADS)

    Buchholz, B.; Afchine, A.; Ebert, V.

    2014-05-01

    Because of the high travel speed, the complex flow dynamics around an aircraft and the complex dependency of the fluid dynamics on numerous airborne parameters, it is quite difficult to obtain accurate pressure values at a specific instrument location of an aircraft's fuselage. Complex simulations using computational fluid dynamics (CFD) models can in theory computationally "transfer" pressure values from one location to another. However, for long flight patterns, this process is inconvenient and cumbersome. Furthermore these CFD transfer models require a local experimental validation, which is rarely available. In this paper, we describe an integrated approach for a spectroscopic, calibration-free, in-flight pressure determination in an open-path White cell on an aircraft fuselage using ambient, atmospheric water vapour as the "sensor species". The presented measurements are realized with the HAI (Hygrometer for Atmospheric Investigations) instrument, built for multiphase water detection via calibration-free TDLAS (tunable diode laser absorption spectroscopy). The pressure determination is based on raw data used for H2O concentration measurement, but with a different post-flight evaluation method, and can therefore be conducted at deferred time intervals on any desired flight track. The spectroscopic pressure is compared in-flight with the static ambient pressure of the aircraft avionic system and a micro-mechanical pressure sensor, located next to the open-path cell, over a pressure range from 150 hPa to 800 hPa, and a water vapour concentration range of more than three orders of magnitude. The correlation between the micro-mechanical pressure sensor measurements and the spectroscopic pressure measurements show an average deviation from linearity of only 0.14% and a small offset of 9.5 hPa. For the spectroscopic pressure evaluation we derive measurement uncertainties under laboratory conditions of 3.2% and 5.1% during in flight operation on the HALO airplane

  6. Rapid, optical measurement of the atmospheric pressure on a fast research aircraft using open-path TDLAS

    NASA Astrophysics Data System (ADS)

    Buchholz, B.; Afchine, A.; Ebert, V.

    2014-11-01

    Because of the high travel speed, the complex flow dynamics around an aircraft, and the complex dependency of the fluid dynamics on numerous airborne parameters, it is quite difficult to obtain accurate pressure values at a specific instrument location of an aircraft's fuselage. Complex simulations using computational fluid dynamics (CFD) models can in theory computationally "transfer" pressure values from one location to another. However, for long flight patterns, this process is inconvenient and cumbersome. Furthermore, these CFD transfer models require a local experimental validation, which is rarely available. In this paper, we describe an integrated approach for a spectroscopic, calibration-free, in-flight pressure determination in an open-path White cell on an aircraft fuselage using ambient, atmospheric water vapour as the "sensor species". The presented measurements are realised with the HAI (Hygrometer for Atmospheric Investigations) instrument, built for multiphase water detection via calibration-free TDLAS (tunable diode laser absorption spectroscopy). The pressure determination is based on raw data used for H2O concentration measurement, but with a different post-flight evaluation method, and can therefore be conducted at deferred time intervals on any desired flight track. The spectroscopic pressure is compared in-flight with the static ambient pressure of the aircraft avionic system and a micro-mechanical pressure sensor, located next to the open-path cell, over a pressure range from 150 to 800 hPa, and a water vapour concentration range of more than 3 orders of magnitude. The correlation between the micro-mechanical pressure sensor measurements and the spectroscopic pressure measurements shows an average deviation from linearity of only 0.14% and a small offset of 9.5 hPa. For the spectroscopic pressure evaluation we derive measurement uncertainties under laboratory conditions of 3.2 and 5.1% during in-flight operation on the HALO airplane. Under

  7. Reactor moderator, pressure vessel, and heat rejection system of an open-cycle gas core nuclear rocket concept

    NASA Technical Reports Server (NTRS)

    Taylor, M. F.; Whitmarsh, C. L., Jr.; Sirocky, P. J., Jr.; Iwanczyke, L. C.

    1973-01-01

    A preliminary design study of a conceptual 6000-megawatt open-cycle gas-core nuclear rocket engine system was made. The engine has a thrust of 196,600 newtons (44,200 lb) and a specific impulse of 4400 seconds. The nuclear fuel is uranium-235 and the propellant is hydrogen. Critical fuel mass was calculated for several reactor configurations. Major components of the reactor (reflector, pressure vessel, and waste heat rejection system) were considered conceptually and were sized.

  8. Dynamics of Surfactant Liquid Plugs at Bifurcating Lung Airway Models

    NASA Astrophysics Data System (ADS)

    Tavana, Hossein

    2013-11-01

    A surfactant liquid plug forms in the trachea during surfactant replacement therapy (SRT) of premature babies. Under air pressure, the plug propagates downstream and continuously divides into smaller daughter plugs at continuously branching lung airways. Propagating plugs deposit a thin film on airway walls to reduce surface tension and facilitate breathing. The effectiveness of SRT greatly depends on the final distribution of instilled surfactant within airways. To understand this process, we investigate dynamics of splitting of surfactant plugs in engineered bifurcating airway models. A liquid plug is instilled in the parent tube to propagate and split at the bifurcation. A split ratio, R, is defined as the ratio of daughter plug lengths in the top and bottom daughter airway tubes and studied as a function of the 3D orientation of airways and different flow conditions. For a given Capillary number (Ca), orienting airways farther away from a horizontal position reduced R due to the flow of a larger volume into the gravitationally favored daughter airway. At each orientation, R increased with 0.0005 < Ca < 0.05. This effect diminished by decrease in airways diameter. This approach will help elucidate surfactant distribution in airways and develop effective SRT strategies.

  9. Impact of airway morphological changes on pulmonary flows in scoliosis

    NASA Astrophysics Data System (ADS)

    Farrell, James; Garrido, Enrique; Valluri, Prashant

    2016-11-01

    The relationship between thoracic deformity in scoliosis and lung function is poorly understood. In a pilot study, we reviewed computed tomography (CT) routine scans of patients undergoing scoliosis surgery. The CT scans were processed to segment the anatomy of the airways, lung and spine. A three-dimensional model was created to study the anatomical relationship. Preliminary analysis showed significant airway morphological differences depending on the anterior position of the spine. A computational fluid dynamics (CFD) study was also conducted on the airway geometry using the inspiratory scans. The CFD model assuming non-compliant airway walls was capable of showing pressure drops in areas of high airway resistance, but was unable to predict regional ventilation differences. Our results indicate a dependence between the dynamic deformation of the airway during breathing and lung function. Dynamic structural deformation must therefore be incorporated within any modelling approaches to guide clinicians on the decision to perform surgical correction of the scoliosis.

  10. Modeling Upper Airway Collapse by a Finite Element Model with Regional Tissue Properties

    PubMed Central

    Xu, Chun; Brennick, Michael J.; Dougherty, Lawrence; Wootton, David M.

    2009-01-01

    This study presents a new computational system for modeling the upper airway in rats that combines tagged magnetic resonance imaging (MRI) with tissue material properties to predict three-dimensional (3D) airway motion. The model is capable of predicting airway wall and tissue deformation under airway pressure loading up to airway collapse. The model demonstrates that oropharynx collapse pressure depends primarily on ventral wall (tongue muscle) elastic modulus and airway architecture. An iterative approach that involves substituting alternative possible tissue elastic moduli was used to improve model precision. The proposed 3D model accounts for stress-strain relationships in the complex upper airway that should present new opportunities for understanding pathogenesis of airway collapse, improving diagnosis and developing treatments. PMID:19747871

  11. Pico Gauges for Minimally Invasive Intracellular Hydrostatic Pressure Measurements1[C][W][OPEN

    PubMed Central

    Knoblauch, Jan; Mullendore, Daniel L.; Jensen, Kaare H.; Knoblauch, Michael

    2014-01-01

    Intracellular pressure has a multitude of functions in cells surrounded by a cell wall or similar matrix in all kingdoms of life. The functions include cell growth, nastic movements, and penetration of tissue by parasites. The precise measurement of intracellular pressure in the majority of cells, however, remains difficult or impossible due to their small size and/or sensitivity to manipulation. Here, we report on a method that allows precise measurements in basically any cell type over all ranges of pressure. It is based on the compression of nanoliter and picoliter volumes of oil entrapped in the tip of microcapillaries, which we call pico gauges. The production of pico gauges can be accomplished with standard laboratory equipment, and measurements are comparably easy to conduct. Example pressure measurements are performed on cells that are difficult or impossible to measure with other methods. PMID:25232014

  12. Open loop pneumatic control of a Lysholm engine or turbine exhaust pressure

    SciTech Connect

    Plonski, B.A.

    1981-07-17

    A Lysholm engine, or helical screw expander, is currently being evaluated at the University of California, Berkeley for staging with a conventional turbine in geothermal energy conversion. A pneumatic closed loop, proportional-integral control system was implemented to control the Lysholm engine's exhaust pressure for performance testing of the engine at constant inlet/outlet pressure ratios. The control system will also be used to control the exhaust pressure of the conventional turbine during future testing of the staged Lysholm-turbine system. Analytical modeling of the control system was performed and successful tuning was achieved by applying Ziegler-Nichol's tuning method. Stable control and quick response, of approximately 1 minute, was demonstrated for load and set point changes in desired exhaust pressures.

  13. A Computational Study of the Respiratory Airflow Characteristics in Normal and Obstructed Human Airways

    DTIC Science & Technology

    2014-01-01

    normal and three different obstructed airway geometries, consisting of symmetric, asym- metric, and random obstructions. Fig. 2 shows the geometric ...normal and obstructed airways Airway resistance is a measure of the opposition to the airflow caused by geometric properties, such as airway obstruction...pressure drops. Resistance values were dependent on the degree and geometric distribution of the obstruction sites. In the symmetric obstruction model

  14. Blood flow response in small intestinal loops at different depths during negative pressure wound therapy of the open abdomen.

    PubMed

    Lindstedt, Sandra; Hlebowicz, Joanna

    2013-08-01

    High closure rates of the open abdomen have been reported following negative pressure wound therapy (NPWT). However, the method has occasionally been associated with increased development of intestinal fistulae. We have previously shown that the application of NPWT to the open abdomen causes a decrease in microvascular blood flow in the small intestinal loop and the omentum adjacent to the visceral protective layer of the dressing. In this study we investigate whether the negative pressure affects only small intestinal loops lying directly below the dressing or if it also affects small intestinal loops that are not in direct contact with the dressing. Six pigs underwent midline incision and application of NPWT to the open abdomen. The microvascular blood flow was measured in four intestinal loops at different depths from the visceral protective layer, at two different locations: beneath the dressing and at the anterior abdominal wall, before and after the application of NPWT of -50, -70, -100, -120, -150 and -170 mmHg, using laser Doppler velocimetry. Negative pressures between -50 and -170 mmHg caused a significant decrease in the microvascular blood flow in the intestinal loops in direct contact with the visceral protective layer. A slight, but significant, decrease in blood flow was also seen in the intestinal loops lying beneath these loops. The decrease in microvascular blood flow increased with the amount of negative pressure applied. No difference in blood flow was seen in the intestinal loops lying deeper in the abdominal cavity. A decrease in blood flow was seen in the upper two intestinal loops located apically and anteriorly, but not in the lower two, indicating that this is a local effect and that pressure decreases with distance from the source. A long-term decrease in blood flow in the intestinal wall may induce ischaemia and secondary necrosis in the intestinal wall, which could promote the development of intestinal fistulae. We believe that NPWT of

  15. Controversies in Pediatric Perioperative Airways

    PubMed Central

    Klučka, Jozef; Štourač, Petr; Štoudek, Roman; Ťoukálková, Michaela; Harazim, Hana; Kosinová, Martina

    2015-01-01

    Pediatric airway management is a challenge in routine anesthesia practice. Any airway-related complication due to improper procedure can have catastrophic consequences in pediatric patients. The authors reviewed the current relevant literature using the following data bases: Google Scholar, PubMed, Medline (OVID SP), and Dynamed, and the following keywords: Airway/s, Children, Pediatric, Difficult Airways, and Controversies. From a summary of the data, we identified several controversies: difficult airway prediction, difficult airway management, cuffed versus uncuffed endotracheal tubes for securing pediatric airways, rapid sequence induction (RSI), laryngeal mask versus endotracheal tube, and extubation timing. The data show that pediatric anesthesia practice in perioperative airway management is currently lacking the strong evidence-based medicine (EBM) data that is available for adult subpopulations. A number of procedural steps in airway management are derived only from adult populations. However, the objective is the same irrespective of patient age: proper securing of the airway and oxygenation of the patient. PMID:26759809

  16. Nonlinear Compliance Modulates Dynamic Bronchoconstriction in a Multiscale Airway Model

    PubMed Central

    Hiorns, Jonathan E.; Jensen, Oliver E.; Brook, Bindi S.

    2014-01-01

    The role of breathing and deep inspirations (DI) in modulating airway hyperresponsiveness remains poorly understood. In particular, DIs are potent bronchodilators of constricted airways in nonasthmatic subjects but not in asthmatic subjects. Additionally, length fluctuations (mimicking DIs) have been shown to reduce mean contractile force when applied to airway smooth muscle (ASM) cells and tissue strips. However, these observations are not recapitulated on application of transmural pressure (PTM) oscillations (that mimic tidal breathing and DIs) in isolated intact airways. To shed light on this paradox, we have developed a biomechanical model of the intact airway, accounting for strain-stiffening due to collagen recruitment (a large component of the extracellular matrix (ECM)), and dynamic actomyosin-driven force generation by ASM cells. In agreement with intact airway studies, our model shows that PTM fluctuations at particular mean transmural pressures can lead to only limited bronchodilation. However, our model predicts that moving the airway to a more compliant point on the static pressure-radius relationship (which may involve reducing mean PTM), before applying pressure fluctuations, can generate greater bronchodilation. This difference arises from competition between passive strain-stiffening of ECM and force generation by ASM yielding a highly nonlinear relationship between effective airway stiffness and PTM, which is modified by the presence of contractile agonist. Effectively, the airway at its most compliant may allow for greater strain to be transmitted to subcellular contractile machinery. The model predictions lead us to hypothesize that the maximum possible bronchodilation of an airway depends on its static compliance at the PTM about which the fluctuations are applied. We suggest the design of additional experimental protocols to test this hypothesis. PMID:25517167

  17. Open-Loop Pitch Table Optimization for the Maximum Dynamic Pressure Orion Abort Flight Test

    NASA Technical Reports Server (NTRS)

    Stillwater, Ryan A.

    2009-01-01

    NASA has scheduled the retirement of the space shuttle orbiter fleet at the end of 2010. The Constellation program was created to develop the next generation of human spaceflight vehicles and launch vehicles, known as Orion and Ares respectively. The Orion vehicle is a return to the capsule configuration that was used in the Mercury, Gemini, and Apollo programs. This configuration allows for the inclusion of an abort system that safely removes the capsule from the booster in the event of a failure on launch. The Flight Test Office at NASA's Dryden Flight Research Center has been tasked with the flight testing of the abort system to ensure proper functionality and safety. The abort system will be tested in various scenarios to approximate the conditions encountered during an actual Orion launch. Every abort will have a closed-loop controller with an open-loop backup that will direct the vehicle during the abort. In order to provide the best fit for the desired total angle of attack profile with the open-loop pitch table, the table is tuned using simulated abort trajectories. A pitch table optimization program was created to tune the trajectories in an automated fashion. The program development was divided into three phases. Phase 1 used only the simulated nominal run to tune the open-loop pitch table. Phase 2 used the simulated nominal and three simulated off nominal runs to tune the open-loop pitch table. Phase 3 used the simulated nominal and sixteen simulated off nominal runs to tune the open-loop pitch table. The optimization program allowed for a quicker and more accurate fit to the desired profile as well as allowing for expanded resolution of the pitch table.

  18. In vitro validation and clinical testing of an indirect calorimetry system for ventilated preterm infants that is unaffected by endotracheal tube leaks and can be used during nasal continuous positive airway pressure.

    PubMed

    Bauer, K; Ketteler, J; Laurenz, M; Versmold, H

    2001-03-01

    Energy expenditure measurements in ventilated preterm infants are difficult because indirect calorimetry underestimates energy expenditure during gas leaks around uncuffed endotracheal tubes routinely used in preterm infants or during nasal continuous positive airway pressure (CPAP). We, therefore, developed a breath collector that simultaneously sampled expired air expelled at the ventilator outlet and escaping via the tube leak from the infant's mouth and nose. Our breath collector was combined with a proprietary calorimeter (Deltatrac II). In vitro validation was done by methanol burning (VO(2), 13.8 mL/min; VCO(2), 9.2 mL/min) during intermittent positive pressure ventilation (IPPV) with two commonly used ventilators (Sechrist IV-100B and Infant Star). Measurement error was determined at different ventilator flows, peak inspiratory pressures of 12-24 cm H(2)O, and during a complete tube leak. The mean measurement error with both ventilators was low (VO(2) +/- 3 %, VCO(2) +/- 2 %) even during a complete tube leak and did not increase with peak inspiratory pressure. The system response time was 2 min. In vivo measurements at the bedside were performed in 25 preterm infants (body weight, 537-1402 g). Energy expenditure during IPPV was 40 +/- 9 kcal/kg per day and 46 +/- 15 kcal/kg per day during nasal CPAP. The tube leak in the preterm infants studied during IPPV was 0 to 47 %, and during nasal CPAP 84 to 97 %. In conclusion, indirect calorimetry performed with our breath collector was accurate during IPPV and nasal CPAP and was unaffected by tube leaks.

  19. Comparison of volume controlled ventilation and pressure controlled ventilation in patients undergoing robot-assisted pelvic surgeries: An open-label trial

    PubMed Central

    Jaju, Rishabh; Jaju, Pooja Bihani; Dubey, Mamta; Mohammad, Sadik; Bhargava, AK

    2017-01-01

    Background and Aims: Although volume controlled ventilation (VCV) has been the traditional mode of ventilation in robotic surgery, recently pressure controlled ventilation (PCV) has been used more frequently. However, evidence on whether PCV is superior to VCV is still lacking. We intended to compare the effects of VCV and PCV on respiratory mechanics and haemodynamic in patients undergoing robotic surgeries in steep Trendelenburg position. Methods: This prospective, randomized trial was conducted on sixty patients between 20 and 70 years belonging to the American Society of Anesthesiologist Physical Status I–II. Patients were randomly assigned to VCV group (n = 30), where VCV mode was maintained through anaesthesia, or the PCV group (n = 30), where ventilation mode was changed to PCV after the establishment of 40° Trendelenburg position and pneumoperitoneum. Respiratory (peak and mean airway pressure [APpeak, APmean], dynamic lung compliance [Cdyn] and arterial blood gas analysis) and haemodynamics variables (heart rate, mean blood pressure [MBP] central venous pressure) were measured at baseline (T1), post-Trendelenburg position at 60 min (T2), 120 min (T3) and after resuming supine position (T4). Results: Demographic profile, haemodynamic variables, oxygen saturation and minute ventilation (MV) were comparable between two groups. Despite similar values of APmean, APpeak was significantly higher in VCV group at T2 and T3 as compared to PCV group (P < 0.001). Cdyn and PaCO2 were also better in PCV group than in VCV group (P < 0.001 and 0.045, respectively). Conclusion: PCV should be preferred in robotic pelvic surgeries as it offers lower airway pressures, greater Cdyn and a better-preserved ventilation-perfusion matching for the same levels of MV. PMID:28216699

  20. A Pilot Study on the Efficacy of Continuous Positive Airway Pressure on the Manifestations of Ménière's Disease in Patients with Concomitant Obstructive Sleep Apnea Syndrome

    PubMed Central

    Nakayama, Meiho; Masuda, Ayako; Ando, Kayoko Bhardwaj; Arima, Sachie; Kabaya, Kayoko; Inagaki, Akira; Nakamura, Yoshihisa; Suzuki, Motohiko; Brodie, Hilary; Diaz, Rodney C.; Murakami, Shingo

    2015-01-01

    Objective: To evaluate the effect of continuous positive airway pressure (CPAP) therapy on Ménière's disease patients with concomitant obstructive sleep apnea syndrome (OSAS), since recent reports suggest OSAS may cause dysfunction of the vestibular system. Study Design: Prospective study using CPAP administered to patients diagnosed with “Definite Ménière's disease” according to the guidelines of the American Academy of Otolaryngology— Head and Neck Surgery and combined with OSAS. Setting: University hospital. Methods: Twenty consecutive patients, 14 male and 6 female with active, unilateral, cochleovestibular Ménière's disease refractory to medical management who also had concurrent OSAS as defined by International Classification of Sleep Disorders, Second Edition were selected to undergo solitary CPAP therapy. Audiometric testing, caloric testing, and DHI survey were conducted before and after CPAP therapy and compared to assess effectiveness of CPAP therapy as utilized for treatment of Ménière's disease. Results: Although caloric testing did not show significant difference, audiometric testing and results of dizziness handicap inventory were significantly improved (p < 0.05) after CPAP therapy only, without standard treatment for Ménière's disease. Conclusions: Recent reports have suggested that OSAS may cause dysfunction of the vestibular system. We investigated whether standard therapy for OSAS would be of benefit in the management of vertigo and hearing loss in Ménière's disease patients. Our study cohort demonstrated significant improvement in both DHI and audiometric testing following solitary CPAP therapy for OSAS. Solitary CPAP therapy may become a new effective treatment strategy for Ménière's disease patients with OSAS, not just only for control of dizziness and vertigo but also for potential benefit of hearing. Citation: Nakayama M, Masuda A, Ando KB, Arima S, Kabaya K, Inagaki A, Nakamura Y, Suzuki M, Brodie H, Diaz RC, Murakami S

  1. Leidenfrost Phenomenon-assisted Thermal Desorption (LPTD) and Its Application to Open Ion Sources at Atmospheric Pressure Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Saha, Subhrakanti; Chen, Lee Chuin; Mandal, Mridul Kanti; Hiraoka, Kenzo

    2013-03-01

    This work describes the development and application of a new thermal desorption technique that makes use of the Leidenfrost phenomenon in open ion sources at atmospheric pressure for direct mass spectrometric detection of ultratrace levels of illicit, therapeutic, and stimulant drugs, toxicants, and peptides (molecular weight above 1 kDa) in their unaltered state from complex real world samples without or with minor sample pretreatment. A low temperature dielectric barrier discharge ion source was used throughout the experiments and the analytical figures of merit of this technique were investigated. Further, this desorption technique coupled with other ionization sources such as electrospray ionization (ESI) and dc corona discharge atmospheric pressure chemical ionization (APCI) in open atmosphere was also investigated. The use of the high-resolution `Exactive Orbitrap' mass spectrometer provided unambiguous identification of trace levels of the targeted compounds from complex mixtures and background noise; the limits of detection for various small organic molecules and peptides treated with this technique were at the level of parts per trillion and 10-9 M, respectively. The high sensitivity of the present technique is attributed to the spontaneous enrichment of analyte molecules during the slow evaporation of the solvent, as well as to the sequential desorption of molecules from complex mixtures based on their volatilities. This newly developed desorption technique is simple and fast, while molecular ions are observed as the major ions.

  2. Fuel Economy and Emissions Effects of Low Tire Pressure, Open Windows, Roof Top and Hitch-Mounted Cargo, and Trailer

    SciTech Connect

    Thomas, John F; Huff, Shean P; West, Brian H

    2014-01-01

    To quantify the fuel economy (FE) effect of some common vehicle accessories or alterations, a compact passenger sedan and a sport utility vehicle (SUV) were subjected to SAE J2263 coastdown procedures. Coastdowns were conducted with low tire pressure, all windows open, with a roof top or hitch-mounted cargo carrier, and with the SUV pulling an enclosed cargo trailer. From these coastdowns, vehicle dynamometer coefficients were developed which enabled the execution of vehicle dynamometer experiments to determine the effect of these changes on vehicle FE and emissions over standard drive cycles and at steady highway speeds. The FE penalty associated with the rooftop cargo box mounted on the compact sedan was as high as 25-27% at higher speeds, where the aerodynamic drag is most pronounced. For both vehicles, use of a hitch mounted cargo tray carrying a similar load resulted in very small FE penalties, unlike the rooftop cargo box. The results for the SUV pulling a 3500 pound enclosed cargo trailer were rather dramatic, resulting in FE penalties ranging from 30%, for the city cycle, to 50% at 80 mph, at which point significant CO generation indicated protective enrichment due to high load. Low tire pressure cases resulted in negligible to 10% FE penalty depending on the specific case and test point. Driving with all four windows open decreased FE by 4-8.5% for the compact sedan, and 1-4% for the SUV.

  3. Open-loop (feed-forward) and feedback control of coronary blood flow during exercise, cardiac pacing, and pressure changes.

    PubMed

    Pradhan, Ranjan K; Feigl, Eric O; Gorman, Mark W; Brengelmann, George L; Beard, Daniel A

    2016-06-01

    A control system model was developed to analyze data on in vivo coronary blood flow regulation and to probe how different mechanisms work together to control coronary flow from rest to exercise, and under a variety of experimental conditions, including cardiac pacing and with changes in coronary arterial pressure (autoregulation). In the model coronary flow is determined by the combined action of a feedback pathway signal that is determined by the level of plasma ATP in coronary venous blood, an adrenergic open-loop (feed-forward) signal that increases with exercise, and a contribution of pressure-mediated myogenic control. The model was identified based on data from exercise experiments where myocardial oxygen extraction, coronary flow, cardiac interstitial norepinephrine concentration, and arterial and coronary venous plasma ATP concentrations were measured during control and during adrenergic and purinergic receptor blockade conditions. The identified model was used to quantify the relative contributions of open-loop and feedback pathways and to illustrate the degree of redundancy in the control of coronary flow. The results indicate that the adrenergic open-loop control component is responsible for most of the increase in coronary blood flow that occurs during high levels of exercise. However, the adenine nucleotide-mediated metabolic feedback control component is essential. The model was evaluated by predicting coronary flow in cardiac pacing and autoregulation experiments with reasonable fits to the data. The analysis shows that a model in which coronary venous plasma adenine nucleotides are a signal in local metabolic feedback control of coronary flow is consistent with the available data.

  4. Patterns of recruitment and injury in a heterogeneous airway network model

    PubMed Central

    Stewart, Peter S.; Jensen, Oliver E.

    2015-01-01

    In respiratory distress, lung airways become flooded with liquid and may collapse due to surface-tension forces acting on air–liquid interfaces, inhibiting gas exchange. This paper proposes a mathematical multiscale model for the mechanical ventilation of a network of occluded airways, where air is forced into the network at a fixed tidal volume, allowing investigation of optimal recruitment strategies. The temporal response is derived from mechanistic models of individual airway reopening, incorporating feedback on the airway pressure due to recruitment. The model accounts for stochastic variability in airway diameter and stiffness across and between generations. For weak heterogeneity, the network is completely ventilated via one or more avalanches of recruitment (with airways recruited in quick succession), each characterized by a transient decrease in the airway pressure; avalanches become more erratic for airways that are initially more flooded. However, the time taken for complete ventilation of the network increases significantly as the network becomes more heterogeneous, leading to increased stresses on airway walls. The model predicts that the most peripheral airways are most at risk of ventilation-induced damage. A positive-end-expiratory pressure reduces the total recruitment time but at the cost of larger stresses exerted on airway walls. PMID:26423440

  5. Hybrid Simulation of Supersonic Flow of Weakly Ionized Plasma along Open Field Magnetic Line Effect of Background Pressure

    NASA Astrophysics Data System (ADS)

    Laosunthara, Ampan; Akatsuka, Hiroshi

    2016-09-01

    In previous study, we experimentally examined physical properties of supersonic flow of weakly ionized expanding arc-jet plasma through an open magnetic field line (Bmax 0.16T). We found supersonic velocity of helium plasma up to Mach 3 and the space potential drop at the end of the magnets. To understand the plasma in numerical point of view, the flows of ion and neutral are treated by particle-based Direct Simulation Monte Carlo (DSMC) method, electron is treated as a fluid. The previous numerical study, we assumed 2 conditions. Ion and electron temperatures were the same (LTE condition). Ion and electron velocities were the same (current-free condition). We found that ion velocity decreased by collision with residual gas molecules (background pressure). We also found that space potential changing with background pressure. In other words, it was indicated that electric field exists and the current-free assumption is not proper. In this study, we add electron continuity and electron momentum equations to obtain electron velocity and space potential. We find that space potential changing with background pressure slightly. It is indicated that electron is essential to space potential formation than ion.

  6. High-pressure open-channel on-chip electroosmotic pump for nanoflow high performance liquid chromatography.

    PubMed

    Wang, Wei; Gu, Congying; Lynch, Kyle B; Lu, Joann J; Zhang, Zhengyu; Pu, Qiaosheng; Liu, Shaorong

    2014-02-18

    Here, we construct an open-channel on-chip electroosmotic pump capable of generating pressures up to ∼170 bar and flow rates up to ∼500 nL/min, adequate for high performance liquid chromatographic (HPLC) separations. A great feature of this pump is that a number of its basic pump units can be connected in series to enhance its pumping power; the output pressure is directly proportional to the number of pump units connected. This additive nature is excellent and useful, and no other pumps can work in this fashion. We demonstrate the feasibility of using this pump to perform nanoflow HPLC separations; tryptic digests of bovine serum albumin (BSA), transferrin factor (TF), and human immunoglobulins (IgG) are utilized as exemplary samples. We also compare the performance of our electroosmotic (EO)-driven HPLC with Agilent 1200 HPLC; comparable efficiencies, resolutions, and peak capacities are obtained. Since the pump is based on electroosmosis, it has no moving parts. The common material and process also allow this pump to be integrated with other microfabricated functional components. Development of this high-pressure on-chip pump will have a profound impact on the advancement of lab-on-a-chip devices.

  7. The Evolution of Mechanisms Driving the Stomatal Response to Vapor Pressure Deficit1[OPEN

    PubMed Central

    McAdam, Scott A.M.; Brodribb, Timothy J.

    2015-01-01

    Stomatal responses to vapor pressure deficit (VPD) are a principal means by which vascular land plants regulate daytime transpiration. While much work has focused on characterizing and modeling this response, there remains no consensus as to the mechanism that drives it. Explanations range from passive regulation by leaf hydration to biochemical regulation by the phytohormone abscisic acid (ABA). We monitored ABA levels, leaf gas exchange, and water status in a diversity of vascular land plants exposed to a symmetrical, mild transition in VPD. The stomata in basal lineages of vascular plants, including gymnosperms, appeared to respond passively to changes in leaf water status induced by VPD perturbation, with minimal changes in foliar ABA levels and no hysteresis in stomatal action. In contrast, foliar ABA appeared to drive the stomatal response to VPD in our angiosperm samples. Increased foliar ABA level at high VPD in angiosperm species resulted in hysteresis in the recovery of stomatal conductance; this was most pronounced in herbaceous species. Increased levels of ABA in the leaf epidermis were found to originate from sites of synthesis in other parts of the leaf rather than from the guard cells themselves. The transition from a passive regulation to ABA regulation of the stomatal response to VPD in the earliest angiosperms is likely to have had critical implications for the ecological success of this lineage. PMID:25637454

  8. Performance of adjustable pressure-limiting (APL) valves in two different modern anaesthesia machines.

    PubMed

    Thomas, J; Weiss, M; Schmidt, A R; Buehler, P K

    2017-01-01

    The ability to gently ventilate a patient's lungs using a self-inflating bag requires a properly working adjustable pressure-limiting (APL) valve. We compared the performance of the APL valves of the GE Aisys CS(2) and the Draeger Fabius anaesthetic machines during closure and opening from 1-20 and from 20-1 cmH2 O, using standardised experimental baby and adolescent patient lung models. Airway pressures and inspiratory tidal volumes were measured using an ASL-5000 test lung and a GE Aisys CS(2) near-patient spirometry sensors. In both lung models, the GE Aisys CS(2) APL valves demonstrated non-linear behaviours for airway pressures and for inspiratory tidal volumes, with a sharp increase at set APL pressure levels of 8-10 cmH2 O. With further closure of the GE Aisys CS(2) APL valves up to 20 cmH2 O, inspiratory tidal volumes decreased to ~50% of the highest values measured. Airway pressures in the Draeger Fabius APL valves demonstrated a near linear increase and decrease. Airway pressure values measured in the Draeger Fabius were never higher than those set by the APL valves, whereas in the GE Aisys CS(2) , they considerably exceeded set pressures (by up to 27 cmH2 O). We conclude that the performance of the GE Aisys CS(2) APL valve does not allow safe bag-assisted ventilation of a patient's lungs.

  9. Application of the open-lung concept during positive-pressure ventilation reduces pulmonary inflammation in newborn piglets.

    PubMed

    van Kaam, Anton H; Dik, Willem A; Haitsma, Jack J; De Jaegere, Anne; Naber, Birgitta A; van Aalderen, Wim M; Kok, Joke H; Lachmann, Burkhard

    2003-01-01

    It has been shown that application of the open-lung concept (OLC) during high-frequency oscillatory ventilation (HFOV) attenuates pulmonary inflammation. We hypothesized that this attenuation could also be achieved by applying the OLC during positive-pressure ventilation (PPV). After repeated whole-lung lavage, newborn piglets were assigned to one of three ventilation groups: (1) PPV(OLC); (2) HFOV(OLC), or (3) conventional PPV (PPV(CON)). After a ventilation period of 5 h, analysis of bronchoalveolar lavage fluid showed a reduced influx of polymorphonuclear neutrophils, interleukin 8, and thrombin activity in both OLC groups as compared with the PPV(CON) group. There were no differences in tumor necrosis factor alpha levels. We conclude that application of the OLC during PPV reduces pulmonary inflammation as compared with conventional PPV and that the magnitude of this reduction is comparable to that of HFOV.

  10. Modeling the dynamics of airway constriction: effects of agonist transport and binding.

    PubMed

    Amin, Samir D; Majumdar, Arnab; Frey, Urs; Suki, Béla

    2010-08-01

    Recent advances have revealed that during exogenous airway challenge, airway diameters cannot be adequately predicted by their initial diameters. Furthermore, airway diameters can also vary greatly in time on scales shorter than a breath. To better understand these phenomena, we developed a multiscale model that allowed us to simulate aerosol challenge in the airways during ventilation. The model incorporates agonist-receptor binding kinetics to govern the temporal response of airway smooth muscle contraction on individual airway segments, which, together with airway wall mechanics, determines local airway caliber. Global agonist transport and deposition are coupled with pressure-driven flow, linking local airway constrictions with global flow dynamics. During the course of challenge, airway constriction alters the flow pattern, redistributing the agonist to less constricted regions. This results in a negative feedback that may be a protective property of the normal lung. As a consequence, repetitive challenge can cause spatial constriction patterns to evolve in time, resulting in a loss of predictability of airway diameters. Additionally, the model offers new insights into several phenomena including the intra- and interbreath dynamics of airway constriction throughout the tree structure.

  11. Lens Position Parameters as Predictors of Intraocular Pressure Reduction After Cataract Surgery in Nonglaucomatous Patients With Open Angles

    PubMed Central

    Hsu, Chi-Hsin; Kakigi, Caitlin L.; Lin, Shuai-Chun; Wang, Yuan-Hung; Porco, Travis; Lin, Shan C.

    2015-01-01

    Purpose To evaluate the relationship between lens position parameters and intraocular pressure (IOP) reduction after cataract surgery in nonglaucomatous eyes with open angles. Methods The main outcome of the prospective study was percentage of IOP change, which was calculated using the preoperative IOP and the IOP 4 months after cataract surgery in nonglaucomatous eyes with open angles. Lens position (LP), defined as anterior chamber depth (ACD) + 1/2 lens thickness (LT), was assessed preoperatively using parameters from optical biometry. Preoperative IOP, central corneal thickness, ACD, LT, axial length (AXL), and the ratio of preoperative IOP to ACD (PD ratio) were also evaluated as potential predictors of percentage of IOP change. The predictive values of the parameters we found to be associated with the primary outcome were compared. Results Four months after cataract surgery, the average IOP reduction was 2.03 ± 2.42 mm Hg, a 12.74% reduction from the preoperative mean of 14.5 ± 3.05 mm Hg. Lens position was correlated with IOP reduction percentage after adjusting for confounders (P = 0.002). Higher preoperative IOP, shallower ACD, shorter AXL, and thicker LT were significantly associated with percentage of IOP decrease. Although not statistically significant, LP was a better predictor of percentage of IOP change compared to PD ratio, preoperative IOP, and ACD. Conclusions The percentage of IOP reduction after cataract surgery in nonglaucomatous eyes with open angles is greater in more anteriorly positioned lenses. Lens position, which is convenient to compute by basic ocular biometric data, is an accessible predictor with considerable predictive value for postoperative IOP change. PMID:26650901

  12. Fluctuation in systolic blood pressure is a major systemic risk factor for development of primary open-angle glaucoma

    PubMed Central

    Lee, Na Young; Jung, Younhea; Han, Kyungdo; Park, Chan Kee

    2017-01-01

    We evaluated the risk of development of primary open-angle glaucoma (POAG) in terms of variability in BP using a nationwide, population-based, 11-year longitudinal study using the Korean National Health Insurance Research Database. We included patients who underwent health care examinations more than twice between January 2002 and December 2006. We divided all subjects by the quartiles of variability in systolic blood pressure (SBP), diastolic blood pressure (DBP), and the difference between SBP and DBP. Of the total of 80,021 included subjects, 910 were diagnosed with POAG between January 2007 and December 2013. Both the Kaplan-Meier survival curves and log-rank test data indicated that patients with higher-level BP variability developed POAG significantly more frequently than did patients with lower-level variability (P < 0.001). On multivariate Cox’s regression modeling including gender, age, sex, household income, smoking status, level of alcohol intake, extent of exercise, diabetes mellitus status, dyslipidemia status, SBP, and DBP; the hazard ratios among the highest and lowest quartiles of SD SBP and CV SBP were 1.256 and 1.238, respectively. Our findings suggest that subjects in the highest quartile of SBP variability were significantly more likely to develop POAG in our population-based sample of Korean adults. PMID:28262703

  13. Estimated Cerebrospina Fluid Pressure and the 5-Year Incidence of Primary Open-Angle Glaucoma in a Chinese Population

    PubMed Central

    Zhong, Hua; Tao, Yijin; Yuan, Yuansheng; Pan, Chen-Wei

    2016-01-01

    Purpose We aim to assess the longitudinal association between baseline estimated cerebrospinal fluid pressure (CSFP) and 5-year incident primary open angle glaucoma (POAG) in a population-based sample of Bai Chinese living in rural China. Methods Among the 2133 Bai Chinese aged 50 years or older who had participated in the baseline examination of the Yunnan Minority Eye Study, 1520 (71.3%) attended the follow-up examination after five years and 1485 were at risk of developing POAG. Participants underwent comprehensive ophthalmic examinations at both baseline and follow-up surveys. CSFP in mmHg was estimated as 0.55 × body mass index (kg/m2) + 0.16 × diastolic blood pressure (mmHg)-0.18 × age (years)-1.91. Glaucoma was defined using the International Society of Geographical and Epidemiological Ophthalmology Classification criteria. Multivariate logistic regression models were established to determine the association between baseline CSFP and incident POAG. Results After a mean follow-up time of 5 years, 19 new cases of POAG were detected, with an incidence rate of 1.3% (95% confidence interval, 0.7–1.9%). In multivariate logistic regression analysis, after adjusting for age, gender, education, intraocular pressure, central corneal thickness, hypertension and diabetes, no significant associations, nor any trends, were evident between baseline estimated CSFP and incident POAG. The association between estimated CSFP per mmHg increase in baseline and 5-year incidence of POAG was also non-significant, with adjusted relative risk of 0.96 (P = 0.11) in multivariate analysis. Conclusions This longitudinal cohort study does not support previously observed cross-sectional association between estimated CSFP and POAG in population-based studies. PMID:27611879

  14. Flow characteristics in the airways of a COPD patient with a saber-sheath trachea

    NASA Astrophysics Data System (ADS)

    Jin, Dohyun; Choi, Haecheon; Lee, Changhyun; Choi, Jiwoong; Kim, Kwanggi

    2016-11-01

    The chronic obstructive pulmonary disease (COPD) is a lung disease characterized by the irreversible airflow limitation caused by the damaged small airways and air sacs. Although COPD is not a disease of the trachea, many patients with COPD have saber-sheath tracheas. The effects of this morphological change in the trachea geometry on airflow are investigated in the present study. An unstructured finite volume method is used for the simulations during tidal breathing in normal and COPD airways, respectively. During inspiration, local large pressure drop is observed in the saber-sheath region of the COPD patient. During expiration, vortical structures are observed at the right main bronchus of the COPD airway, while the flow in the normal airway remains nearly laminar. High wall shear stress exists at convex regions of both airways during inspiration and expiration. However, due to the morphological changes in the COPD airway, relatively higher wall shear stress is observed in the patient airways.

  15. Airway evaluation in obstructive sleep apnea.

    PubMed

    Stuck, Boris A; Maurer, Joachim T

    2008-12-01

    As the interest in sleep-disordered breathing has increased, various attempts have been made to assess upper airway anatomy in patients with this relatively frequent disorder. The aim is not only to reveal potential differences in upper airway anatomy to better understand origin and pathophysiology of the disease but also to improve patient management and treatment success. The present review is based on a systematic literature search with regard to upper airway evaluation in sleep-disordered breathing; the articles were selected and discussed in light of our clinical experiences. Based on clinical assessment including endoscopy during wakefulness, the value of the Mueller Maneuver, static radiologic imaging techniques (X-ray cephalometry, computed tomography (CT) scanning and magnetic resonance imaging (MRI)), dynamic scanning protocols (e.g. ultrafast CT or cine MRI), upper airway endoscopy during sleep and sedated sleep, pressure measurements and the assessment of the critical closing pressure are discussed. Each technique itself and its history in the field of sleep medicine are briefly reviewed and problems of standardization and interpretation are discussed when appropriate. Insights into the pathophysiology of the disease gained with the help of the investigational techniques are presented and the impact of the techniques on patient management is reported. Although all these additional techniques for upper airway assessment have substantially improved our understanding of sleep-disordered breathing, their significance in daily practice is limited. In contrast to the widespread use of the Mueller maneuver and sedated endoscopy, convincing data supporting their use in terms of treatment outcome are lacking. So far, there is only very limited evidence that selected techniques improve treatment outcome for selected indications. In general, there is not enough evidence that these techniques are superior to the routine clinical assessment.

  16. What does airway resistance tell us about lung function?

    PubMed

    Kaminsky, David A

    2012-01-01

    Spirometry is considered the primary method to detect the air flow limitation associated with obstructive lung disease. However, air flow limitation is the end-result of many factors that contribute to obstructive lung disease. One of these factors is increased airway resistance. Airway resistance is traditionally measured by relating air flow and driving pressure using body plethysmography, thus deriving airway resistance (R(aw)), specific airway resistance (sR(aw)), and specific airway conductance (sG(aw)). Other methods to measure airway resistance include the forced oscillation technique (FOT), which allows calculation of respiratory system resistance (R(RS)) and reactance (X(RS)), and the interrupter technique, which allows calculation of interrupter resistance (R(int)). An advantage of these other methods is that they may be easier to perform than spirometry, making them particularly suited to patients who cannot perform spirometry, such as young children, patients with neuromuscular disorders, or patients on mechanical ventilation. Since spirometry also requires a deep inhalation, which can alter airway resistance, these alternative methods may provide more sensitive measures of airway resistance. Furthermore, the FOT provides unique information about lung mechanics that is not available from analysis using spirometry, body plethysmography, or the interrupter technique. However, it is unclear whether any of these measures of airway resistance contribute clinically important information to the traditional measures derived from spirometry (FEV(1), FVC, and FEV(1)/FVC). The purpose of this paper is to review the physiology and methodology of these measures of airway resistance, and then focus on their clinical utility in relation to each other and to spirometry.

  17. A randomised trial of peri-operative positive airway pressure for postoperative delirium in patients at risk for obstructive sleep apnoea after regional anaesthesia with sedation or general anaesthesia for joint arthroplasty.

    PubMed

    Nadler, J W; Evans, J L; Fang, E; Preud'Homme, X A; Daughtry, R L; Chapman, J B; Bolognesi, M P; Attarian, D E; Wellman, S S; Krystal, A D

    2017-03-02

    Previous pilot work has established an association between obstructive sleep apnoea and the development of acute postoperative delirium , but it remains unclear to what extent this risk factor is modifiable in the 'real world' peri-operative setting. In a single-blind randomised controlled trial, 135 elderly surgical patients at risk for obstructive sleep apnoea were randomly assigned to receive peri-operative continuous positive airway pressure (CPAP) or routine care. Of the 114 patients who completed the study, 21 (18.4%) experienced delirium. Delirium was equally common in both groups: 21% (12 of 58 subjects) in the CPAP group and 16% (9 of 56 subjects) in the routine care group (OR = 1.36 [95%CI 0.52-3.54], p = 0.53). Delirious subjects were slightly older - mean (SD) age 68.9 (10.7) vs. 64.9 (8.2), p = 0.07 - but had nearly identical pre-operative STOP-Bang scores (4.19 (1.1) versus 4.27 (1.3), p = 0.79). Subjects in the CPAP group used their devices for a median (IQR [range]) of 3 (0.25-5 [0-12]) nights pre-operatively (2.9 (0.1-4.8 [0.0-12.7]) hours per night) and 1 (0-2 [0-2]) nights postoperatively (1.4 (0.0-5.1 [0.0-11.6]) hours per night). Among the CPAP subjects, the residual pre-operative apnoea-hypopnea index had a significant effect on delirium severity (p = 0.0002). Although we confirm that apnoea is associated with postoperative delirium, we did not find that providing a short-course of auto-titrating CPAP affected its likelihood or severity. Voluntary adherence to CPAP is particularly poor during the initiation of therapy.

  18. A multicentre, randomised controlled, non-inferiority trial, comparing high flow therapy with nasal continuous positive airway pressure as primary support for preterm infants with respiratory distress (the HIPSTER trial): study protocol

    PubMed Central

    Roberts, Calum T; Owen, Louise S; Manley, Brett J; Donath, Susan M; Davis, Peter G

    2015-01-01

    Introduction High flow (HF) therapy is an increasingly popular mode of non-invasive respiratory support for preterm infants. While there is now evidence to support the use of HF to reduce extubation failure, there have been no appropriately designed and powered studies to assess the use of HF as primary respiratory support soon after birth. Our hypothesis is that HF is non-inferior to the standard treatment—nasal continuous positive airway pressure (NCPAP)— as primary respiratory support for preterm infants. Methods and analysis The HIPSTER trial is an unblinded, international, multicentre, randomised, non-inferiority trial. Eligible infants are preterm infants of 28–36+6 weeks’ gestational age (GA) who require primary non-invasive respiratory support for respiratory distress in the first 24 h of life. Infants are randomised to treatment with either HF or NCPAP. The primary outcome is treatment failure within 72 h after randomisation, as determined by objective oxygenation, blood gas, and apnoea criteria, or the need for urgent intubation and mechanical ventilation. Secondary outcomes include the incidence of intubation, pneumothorax, bronchopulmonary dysplasia, nasal trauma, costs associated with hospital care and parental stress. With a specified non-inferiority margin of 10%, using a two-sided 95% CI and 90% power, the study requires 375 infants per group (total 750 infants). Ethics and dissemination Ethical approval has been granted by the relevant human research ethics committees at The Royal Women's Hospital (13/12), The Royal Children's Hospital (33144A), The Mercy Hospital for Women (R13/34), and the South-Eastern Norway Regional Health Authority (2013/1657). The trial is currently recruiting at 9 centres in Australia and Norway. The trial results will be published in peer-reviewed international journals, and presented at national and international conferences. Trial registration number Australian New Zealand Clinical Trials Registry ID: ACTRN

  19. Humidified High Flow Nasal Cannula versus Nasal Continuous Positive Airway Pressure as an Initial Respiratory Support in Preterm Infants with Respiratory Distress: a Randomized, Controlled Non-Inferiority Trial.

    PubMed

    Shin, Jeonghee; Park, Kyuhee; Lee, Eun Hee; Choi, Byung Min

    2017-04-01

    Heated, humidified, high-flow nasal cannula (HHFNC) is frequently used as a noninvasive respiratory support for preterm infants with respiratory distress. But there are limited studies that compares HHFNC with nasal continuous positive airway pressure (nCPAP) only as the initial treatment of respiratory distress in preterm infants immediately after birth. The aim of this study is to assess the effectiveness and safety of HHFNC compared to nCPAP for the initial treatment of preterm infants with respiratory distress. Preterm infants at between 30 and 35 weeks of gestational age were randomized to HHFNC or nCPAP when they showed respiratory distress in less than 24 hours of age postnatally. Preterm infants who needed invasive respiratory supports were excluded. Primary outcome was the incidence of treatment failure (defined as need for the intubation or mechanical ventilation). Eighty-five infants were analyzed. Sixteen of 42 infants randomized to HHFNC showed treatment failure compared to 9 of 43 infants using nCPAP (Risk difference 17.17 [-1.90-36.23]; P = 0.099). In terms of the reason for treatment failure, the frequency of hypoxia was significantly higher in the HHFNC group than in the nCPAP group (P = 0.020). There was no difference between the 2 groups in terms of respiratory and clinical outcomes and complications. Although HHFNC is safe compared to nCPAP, it is not certain that HHFNC is effective compared to nCPAP non-inferiorly as an initial respiratory support in preterm infants with respiratory distress.

  20. Humidified High Flow Nasal Cannula versus Nasal Continuous Positive Airway Pressure as an Initial Respiratory Support in Preterm Infants with Respiratory Distress: a Randomized, Controlled Non-Inferiority Trial

    PubMed Central

    2017-01-01

    Heated, humidified, high-flow nasal cannula (HHFNC) is frequently used as a noninvasive respiratory support for preterm infants with respiratory distress. But there are limited studies that compares HHFNC with nasal continuous positive airway pressure (nCPAP) only as the initial treatment of respiratory distress in preterm infants immediately after birth. The aim of this study is to assess the effectiveness and safety of HHFNC compared to nCPAP for the initial treatment of preterm infants with respiratory distress. Preterm infants at between 30 and 35 weeks of gestational age were randomized to HHFNC or nCPAP when they showed respiratory distress in less than 24 hours of age postnatally. Preterm infants who needed invasive respiratory supports were excluded. Primary outcome was the incidence of treatment failure (defined as need for the intubation or mechanical ventilation). Eighty-five infants were analyzed. Sixteen of 42 infants randomized to HHFNC showed treatment failure compared to 9 of 43 infants using nCPAP (Risk difference 17.17 [−1.90–36.23]; P = 0.099). In terms of the reason for treatment failure, the frequency of hypoxia was significantly higher in the HHFNC group than in the nCPAP group (P = 0.020). There was no difference between the 2 groups in terms of respiratory and clinical outcomes and complications. Although HHFNC is safe compared to nCPAP, it is not certain that HHFNC is effective compared to nCPAP non-inferiorly as an initial respiratory support in preterm infants with respiratory distress. PMID:28244292

  1. Oral appliance therapy versus nasal continuous positive airway pressure in obstructive sleep apnea syndrome: a randomized, placebo-controlled trial on self-reported symptoms of common sleep disorders and sleep-related problems.

    PubMed

    Nikolopoulou, Maria; Byraki, Anna; Ahlberg, Jari; Heymans, Martijn W; Hamburger, H L; De Lange, Jan; Lobbezoo, Frank; Aarab, Ghizlane

    2017-03-10

    Obstructive sleep apnea syndrome (OSAS) is associated with several sleep disorders and sleep-related problems. Therefore, the aim of this study was to compare the effects of a mandibular advancement device (MAD) with those of nasal continuous positive airway pressure (nCPAP) on self-reported symptoms of common sleep disorders and sleep-related problems in mild and moderate OSAS patients. In this randomized placebo-controlled trial sixty-four OSAS patients (52.0± 9.6 years) were randomly assigned to an MAD, nCPAP or an intra-oral placebo appliance in a parallel design. All participants filled out the validated Dutch Sleep Disorders Questionnaire (SDQ) twice: one before treatment and one after six months of treatment. With 88 questions, thirteen scales were constructed, representing common sleep disorders and sleep-related problems. Linear mixed model analyses were performed to study differences between the groups for the different SDQ scales over time. The MAD group showed significant improvements over time in symptoms corresponding with "insomnia", "excessive daytime sleepiness", "psychiatric sleep disorder", "periodic limb movements", "sleep apnea", "sleep paralysis", "daytime dysfunction", "hypnagogic hallucinations/dreaming", "restless sleep", "negative conditioning", and "automatic behaviour" (range of P values: 0.000-0.014). These improvements in symptoms were, however, not significantly different from the improvements in symptoms observed in the nCPAP and placebo groups (range of P values: 0.090-0.897). It can be concluded that there is no significant difference between MAD and nCPAP in their positive effects on self-reported symptoms of common sleep disorders and sleep-related problems in mild and moderate OSAS patients. These beneficial effects may be a result of placebo effects. This article is protected by copyright. All rights reserved.

  2. COMPLIANCE MEASUREMENTS OF THE UPPER AIRWAY IN PEDIATRIC DOWN SYNDROME SLEEP APNEA PATIENTS

    PubMed Central

    Subramaniam, Dhananjay Radhakrishnan; Mylavarapu, Goutham; McConnell, Keith; Fleck, Robert J.; Shott, Sally R.; Amin, Raouf S.; Gutmark, Ephraim J.

    2015-01-01

    Compliance of soft tissue and muscle supporting the upper airway are two of several factors contributing to pharyngeal airway collapse. We present a novel, minimally invasive method of estimating regional variations in pharyngeal elasticity. Magnetic resonance images for pediatric sleep apnea patients with Down syndrome (9.5 ± 4.3 years (mean age ± standard deviation)) were analyzed to segment airways corresponding to baseline (no mask pressure) and two positive pressures. A three dimensional map was created to evaluate axial and circumferential variation in radial displacements of the airway, dilated by the positive pressures. The displacements were then normalized with respect to the appropriate transmural pressure and radius of an equivalent circle to obtain a measure of airway compliance. The resulting elasticity maps indicated the least and most compliant regions of the pharynx. Airway stiffness of the most compliant region (403 ± 204 (mean ± standard deviation) Pa) decreased with severity of OSA. The non-linear response of the airway wall to CPAP was patient specific and varied between anatomical locations. We identified two distinct elasticity phenotypes. Patient phenotyping based on airway elasticity can potentially assist clinical practitioners in decision making on the treatments needed to improve airway patency. PMID:26215306

  3. Packed uniform sphere model for solids: interstitial access opening sizes and pressure deficiencies for wetting liquids with comparison to reported experimental results.

    PubMed

    Mayer, Raymond P; Stowe, Robert A

    2006-02-01

    Mathematical relationships have been developed to describe the pressure deficiencies required for drainage and removal of wetting liquids through the access openings to the interstitial void space for a model comprised of uniform packed solid spheres. Access openings and associated pressure deficiencies are defined in terms of the packing and radius of the spheres, using a circular arc approximation for the liquid-vapor portion of the perimeter of the opening. This allows determination of equivalent particle radius rather than equivalent cylindrical pore radius within a porous solid sample by use of standard pressure, porosity and desorption data. For a known particle size and porosity, it allows comparison and prediction of drainage of wetting liquids and pressures required for removal of the liquid from compacted materials and collections of random packed spherical particles. Comparisons are made to experimental packing of spheres. Sorption isotherms for a volatile wetting liquid are presented, covering the access to the interstitial void space, the pendular liquid ring between adjacent touching spheres and the monolayer surface area. The larger size of the interstitial void space compared to the size of the access opening leads to lower imbibition pressures and hysteresis for both volatile and nonvolatile wetting liquids. The relationship to mercury porosimetry and the adjustment for contact angles other than 0 degrees and 180 degrees are discussed.

  4. Upper airway radiographs in infants with upper airway insufficiency.

    PubMed Central

    Tonkin, S L; Davis, S L; Gunn, T R

    1994-01-01

    Upper airway measurements in nine infants considered to be at risk of upper airway insufficiency, six of whom presented after an apnoeic episode, were compared with measurements taken in two age groups of healthy infants. Paired, inspiratory and expiratory, lateral upper airway radiographs were obtained while the infants were awake and breathing quietly. The radiographs of all nine infants demonstrated narrowing in the oropharyngeal portion of the airway during inspiration and in six infants there was ballooning of the upper airway during expiration. Seven of the nine infants subsequently experienced recurrent apnoeic episodes which required vigorous stimulation to restore breathing. Experience suggests that respiratory phase timed radiographs are a useful adjunct to the evaluation of infants who are suspected of having upper airway dysfunction. They provide information regarding both the dimensions and compliance of the upper airway as well as the site of any restriction. Images PMID:8048825

  5. Airway-parenchyma uncoupling in nocturnal asthma.

    PubMed

    Irvin, C G; Pak, J; Martin, R J

    2000-01-01

    Airway flow resistance is well known to be dependent upon lung volume. The rise in lung volume that occurs in asthma is therefore thought to be an important mechanism that defends airway patency. The purpose of the current study was to investigate the interdependence or mechanical coupling between airways and lung parenchyma during the inflammatory processes that occur in the patient with nocturnal asthma. Five patients with documented nocturnal asthma were studied in both a vertical and a horizontal body plethysmograph. Lung volume was altered with continuous negative pressure as applied to the chest wall with a poncho cuirass in different postures and during sleep. We found during the awake phase that an increase in lung volume decreased lower pulmonary resistance (Rlp); however, within 30 min of sleep onset, functional residual capacity (FRC) fell and Rlp rose more than would be expected for the fall in FRC. Restoring FRC to presleep values either at an early (half-hour) or a late (3-h) time point did not cause Rlp to significantly fall. A second phase of the study showed that the loss of Rlp dependence on lung volume was not due to the assumption of the supine posture. Indirect measurements of lung compliance were consistent with a stiffening of the lung. We conclude that with sleep there is an immediate uncoupling of the parenchyma to the airway, resulting in a loss of interdependence that persists throughout sleep and may contribute to the morbidity and mortality associated with nocturnal asthma.

  6. External Ventricular Catheters: Is It Appropriate to Use an Open/Monitor Position to Adequately Trend Intracranial Pressure in a Neuroscience Critical Care Environment?

    PubMed

    Sunderland, Nicole E; Villanueva, Nancy E; Pazuchanics, Susan J

    2016-10-01

    Intracranial pressure (ICP) monitoring can be an important assessment tool in critically and acutely ill patients. An external ventricular drain offers a comprehensive way to monitor ICP and drain cerebrospinal fluid. The Monro-Kellie hypothesis, Pascal's principle, and fluid dynamics were used to formulate an assumption that an open/monitor position on the stopcock is an adequate trending measure for ICP monitoring while concurrently draining cerebrospinal fluid. Data were collected from 50 patients and totaled 1053 separate number sets. The open/monitor position was compared with the clamped position every hour. An order for "open to drain" was needed for appropriate measurement and nursing care. Results showed the absolute average differences between open/monitor and clamped positions at 1.6268 mm Hg. This finding suggests that it is appropriate to use an open/monitor position via an external ventricular drain for adequate trending of patients' ICP.

  7. Supraglottic airway devices in children

    PubMed Central

    Ramesh, S; Jayanthi, R

    2011-01-01

    Modern anaesthesia practice in children was made possible by the invention of the endotracheal tube (ET), which made lengthy and complex surgical procedures feasible without the disastrous complications of airway obstruction, aspiration of gastric contents or asphyxia. For decades, endotracheal intubation or bag-and-mask ventilation were the mainstays of airway management. In 1983, this changed with the invention of the laryngeal mask airway (LMA), the first supraglottic airway device that blended features of the facemask with those of the ET, providing ease of placement and hands-free maintenance along with a relatively secure airway. The invention and development of the LMA by Dr. Archie Brain has had a significant impact on the practice of anaesthesia, management of the difficult airway and cardiopulmonary resuscitation in children and neonates. This review article will be a brief about the clinical applications of supraglottic airways in children. PMID:22174464

  8. Intraocular Pressure, Central Corneal Thickness, and Prevalence of Open-Angle Glaucoma: The Los Angeles Latino Eye Study

    PubMed Central

    Francis, Brian A.; Varma, Rohit; Chopra, Vikas; Lai, Mei-Ying; Shtir, Corina; Azen, Stanley P.

    2008-01-01

    Purpose To examine the relationship between the prevalence of open-angle glaucoma (OAG) and intraocular pressure (IOP) and the impact of central corneal thickness (CCT) on this relationship. Design Population based cross-sectional study. Methods The study cohort consisted of 5970 participants from the Los Angeles Latino Eye Study (LALES) with no history of glaucoma treatment and with complete ophthalmic examination data. The relationship between the prevalence of OAG and IOP was contrasted across persons with CCT designated as thin, normal or thick. Results Prevalence of OAG was exponentially related to IOP. When stratified by CCT, persons with thin CCT had a significantly higher prevalence of OAG than did those with normal or thick CCT’s at all levels of IOP. Adjusting each IOP individually for CCT did not impact significantly the relationship between the prevalence of OAG and IOP. Conclusions These findings suggest that adjusting for the impact of CCT on IOP by correction algorithms is not necessary in a population analysis of glaucoma prevalence; CCT and other associated corneal properties, however, are important independent risk factors for the prevalence of OAG. PMID:18672218

  9. Highly efficient photocatalytic TiO2 coatings deposited by open air atmospheric pressure plasma jet with aerosolized TTIP precursor

    NASA Astrophysics Data System (ADS)

    Fakhouri, H.; Ben Salem, D.; Carton, O.; Pulpytel, J.; Arefi-Khonsari, F.

    2014-07-01

    A simple method to deposit photocatalytic TiO2 coatings, at a high rate (20-40 µm s-1), and with a high porosity, is reported in this paper. This method, which allows the treatment of membranes (with an 800 nm pore size), is based on the introduction of a liquid precursor sprayed into an open-air atmospheric pressure plasma jet (APPJ). The photocatalytic activity of the TiO2 thin films prepared by APPJ have been compared with our best N-doped TiO2 thin films, deposited by reactive radio frequency (RF) magnetron sputtering, previously reported in the literature. The morphology, chemical composition, photoelectrochemical, and photocatalytic properties of the coatings have been studied in this paper. Significant control of the porosity and crystallinity was achieved by varying the deposition parameters and the annealing temperature. Under optimized conditions, the TiO2 coatings deposited by APPJ are characterized by a higher photocatalytic activity as compared to the optimized thin films deposited by RF sputtering. This difference can be explained by the higher specific surface of the APPJ coatings. Finally, the most interesting characteristic of this APPJ-liquid spray process is its capacity to treat membranes without blocking the pores, and to produce photocatalytic membranes which can efficiently combine filtration and photocatalysis for water treatment.

  10. Permeability dependence study of the focused ultrasound-induced blood-brain barrier opening at distinct pressures and microbubble diameters using DCE-MRI.

    PubMed

    Vlachos, Fotios; Tung, Yao-Sheng; Konofagou, Elisa

    2011-09-01

    Blood-brain barrier opening using focused ultrasound and microbubbles has been experimentally established as a noninvasive and localized brain drug delivery technique. In this study, the permeability of the opening is assessed in the murine hippocampus after the application of focused ultrasound at three different acoustic pressures and microbubble sizes. Using dynamic contrast-enhanced MRI, the transfer rates were estimated, yielding permeability maps and quantitative K(trans) values for a predefined region of interest. The volume of blood-brain barrier opening according to the K(trans) maps was proportional to both the pressure and the microbubble diameter. A K(trans) plateau of ∼0.05 min(-1) was reached at higher pressures (0.45 and 0.60 MPa) for the larger sized bubbles (4-5 and 6-8 μm), which was on the same order as the K(trans) of the epicranial muscle (no barrier). Smaller bubbles (1-2 μm) yielded significantly lower permeability values. A small percentage (7.5%) of mice showed signs of damage under histological examination, but no correlation with permeability was established. The assessment of the blood-brain barrier permeability properties and their dependence on both the pressure and the microbubble diameter suggests that K(trans) maps may constitute an in vivo tool for the quantification of the efficacy of the focused ultrasound-induced blood-brain barrier opening.

  11. The Tulip GT® airway versus the facemask and Guedel airway: a randomised, controlled, cross-over study by Basic Life Support-trained airway providers in anaesthetised patients.

    PubMed

    Shaikh, A; Robinson, P N; Hasan, M

    2016-03-01

    We performed a randomised, controlled, cross-over study of lung ventilation by Basic Life Support-trained providers using either the Tulip GT® airway or a facemask with a Guedel airway in 60 anaesthetised patients. Successful ventilation was achieved if the provider produced an end-tidal CO2 > 3.5 kPa and a tidal volume > 250 ml in two of the first three breaths, within 60 sec and within two attempts. Fifty-seven (95%) providers achieved successful ventilation using the Tulip GT compared with 35 (58%) using the facemask (p < 0.0001). Comparing the Tulip GT and facemask, the mean (SD) end-tidal CO2 was 5.0 (0.7) kPa vs 2.5 (1.5) kPa, tidal volume was 494 (175) ml vs 286 (186) ml and peak inspiratory pressure was 18.3 (3.4) cmH2 O vs 13.6 (7) cmH2 O respectively (all p < 0.0001). Forty-seven (78%) users favoured the Tulip GT airway. These results are similar to a previous manikin study using the same protocol, suggesting a close correlation between human and manikin studies for this airway device. We conclude that the Tulip GT should be considered as an adjunct to airway management both within and outside hospitals when ventilation is being undertaken by Basic Life Support-trained airway providers.

  12. I-gel versus laryngeal mask airway-Proseal: Comparison of two supraglottic airway devices in short surgical procedures

    PubMed Central

    Jadhav, Poonam A; Dalvi, Naina P; Tendolkar, Bharati A

    2015-01-01

    Background and Aims: Supraglottic airway devices have been established in clinical anesthesia practice and have been previously shown to be safe and efficient. The objective of this prospective, randomized trial was to compare I-Gel with LMA-Proseal in anesthetized spontaneously breathing patients. Material and Methods: Sixty patients undergoing short surgical procedures were randomly assigned to I-gel (Group I) or LMA- Proseal (Group P). Anesthesia was induced with standard doses of propofol and the supraglottic airway device was inserted. We compared the ease and time required for insertion, airway sealing pressure and adverse events. Results: There were no significant differences in demographic and hemodynamic data. I-gel was significantly easier to insert than LMA-Proseal (P < 0.05) (Chi-square test). The mean time for insertion was more with Group P (41 + 09.41 secs) than with Group I (29.53 + 08.23 secs) (P < 0.05). Although the airway sealing pressure was significantly higher with Group P (25.73 + 02.21 cm of H2O), the airway sealing pressure of Group I (20.07 + 02.94 cm of H2O) was very well within normal limit (Student's t test). The success rate of first attempt insertion was more with Group I (P < 0.05). There was no evidence of airway trauma, regurgitation and aspiration. Sore throat was significantly more evident in Group P. Conclusion: I-Gel is a innovative supraglottic device with acceptable airway sealing pressure, easier to insert, less traumatic with lower incidence of sore throat. Hence I-Gel can be a good alternative to LMA-Proseal. PMID:25948905

  13. Air-Q intubating laryngeal airway: A study of the second generation supraglottic airway device

    PubMed Central

    Attarde, Viren Bhaskar; Kotekar, Nalini; Shetty, Sarika M

    2016-01-01

    Background and Aims: Air-Q intubating laryngeal mask airway (ILA) is used as a supraglottic airway device and as a conduit for endotracheal intubation. This study aims to assess the efficacy of the Air-Q ILA regarding ease of insertion, adequacy of ventilation, rate of successful intubation, haemodynamic response and airway morbidity. Methods: Sixty patients presenting for elective surgery at our Medical College Hospital were selected. Following adequate premedication, baseline vital parameters, pulse rate and blood pressure were recorded. Air-Q size 3.5 for patients 50-70 kg and size 4.5 for 70-100 kg was selected. After achieving adequate intubating conditions, Air-Q ILA was introduced. Confirming adequate ventilation, appropriate sized endotracheal tube was advanced through the Air-Q blindly to intubate the trachea. Placement of the endotracheal tube in trachea was confirmed. Results: Air-Q ILA was successfully inserted in 88.3% of patients in first attempt and 11.7% patients in second attempt. Ventilation was adequate in 100% of patients. Intubation was successful in 76.7% of patients with Air-Q ILA. 23.3% of patients were intubated by direct laryngoscopy following failure with two attempts using Air-Q ILA. Post-intubation the change in heart rate was statistically significant (P < 0.0001). 10% of patients were noted to have a sore throat and 5% of patients had mild airway trauma. Conclusion: Air-Q ILA is a reliable device as a supraglottic airway ensuring adequate ventilation as well as a conduit for endotracheal intubation. It benefits the patient by avoiding the stress of direct laryngoscopy and is also superior alternative device for use in a difficult airway. PMID:27212722

  14. Infant flow biphasic nasal continuous positive airway pressure (BP- NCPAP) vs. infant flow NCPAP for the facilitation of extubation in infants' ≤ 1,250 grams: a randomized controlled trial

    PubMed Central

    2012-01-01

    Abstract Background The use of mechanical ventilation is associated with lung injury in preterm infants and therefore the goal is to avoid or minimize its use. To date there is very little consensus on what is considered the "best non-invasive ventilation mode" to be used post-extubation. The objective of this study was to compare the effectiveness of biphasic nasal continuous positive airway pressure (BP-NCPAP) vs. NCPAP in facilitating sustained extubation in infants ≤ 1,250 grams. Methods We performed a randomized controlled trial of BP-NCPAP vs. NCPAP in infants ≤ 1,250 grams extubated for the first time following mechanical ventilation since birth. Infants were extubated using preset criteria or at the discretion of the attending neonatologist. The primary outcome was the incidence of sustained extubation for 7 days. Secondary outcomes included incidence of adverse events and short-term neonatal outcomes. Results Sixty-seven infants received BP-NCPAP and 69 NCPAP. Baseline characteristics were similar between groups. The trial was stopped early due to increased use of non-invasive ventilation from birth, falling short of our calculated sample size of 141 infants per group. The incidence of sustained extubation was not statistically different between the BP-NCPAP vs. NCPAP group (67% vs. 58%, P = 0.27). The incidence of adverse events and short-term neonatal outcomes were similar between the two groups (P > 0.05) except for retinopathy of prematurity which was noted to be higher (P = 0.02) in the BP-NCPAP group. Conclusions Biphasic NCPAP may be used to assist in weaning from mechanical ventilation. The effectiveness and safety of BP-NCPAP compared to NCPAP needs to be confirmed in a large multi-center trial as our study conclusions are limited by inadequate sample size. Clinical Trials Registration # NCT00308789 Source of support Grant # 06-06, Physicians Services Incorporated Foundation, Toronto, Canada. Summit technologies Inc. provided additional NCPAP

  15. Intraocular pressure fluctuation after water drinking test in primary angle-closure glaucoma and primary open-angle glaucoma

    PubMed Central

    Poon, Yi-Chieh; Teng, Mei-Ching; Lin, Pei-Wen; Tsai, Jen-Chia; Lai, Ing-Chou

    2016-01-01

    Context: Only a few studies have assessed intraocular pressure (IOP) changes during the water drinking test (WDT) in patients with primary angle-closure glaucoma (PACG). Aims: The aim of this study is to investigate IOP changes during WDT in patients with PACG versus primary open-angle glaucoma (POAG). Settings and Design: This was a prospective and single tertiary center study. Materials and Methods: PACG and POAG patients (n = 15 each) without prior glaucoma surgery were enrolled and subjected to WDT, wherein they consumed an amount of water proportional to their body weight within 10 min. IOP was measured at baseline and every 15 min for 1 h after water intake. Statistical Analysis Used: Intergroup comparisons were performed using Mann–Whitney U-test for continuous variables and Chi-square test for categorical variables. Wilcoxon signed-ranks test was used for comparisons of IOP before and after water intake in the two groups. Regression analysis was used to determine factors associated with IOP fluctuations during WDT. Results: IOP changes over 1 h after water intake showed no significant differences between groups. The mean maximum fluctuation from baseline was 3.61 ± 2.49 and 3.79 ± 1.91 mmHg, respectively, in the PACG and POAG groups. The mean peak IOP was 19.17 ± 4.32 and 19.87 ± 3.44 mmHg in the PACG and PAOG groups, respectively. The axial length and anterior chamber depth showed no correlations with IOP fluctuations. Conclusions: We found similar IOP fluctuation curves and peak IOP values in both PACG and POAG patients subjected to WDT. These findings suggest that WDT is a useful test to induce IOP peaks in both POAG and PACG patients. PMID:28112134

  16. Fluid Lavage of Open Wounds (FLOW): design and rationale for a large, multicenter collaborative 2 × 3 factorial trial of irrigating pressures and solutions in patients with open fractures

    PubMed Central

    2010-01-01

    Background Open fractures frequently result in serious complications for patients, including infections, wound healing problems, and failure of fracture healing, many of which necessitate subsequent operations. One of the most important steps in the initial management of open fractures is a thorough wound irrigation and debridement to remove any contaminants. There is, however, currently no consensus regarding the optimal approach to irrigating open fracture wounds during the initial operative procedure. The selection of both the type of irrigating fluid and the pressure of fluid delivery remain controversial. The primary objective of this study is to investigate the effects of irrigation solutions (soap vs. normal saline) and pressure (low vs. high; gravity flow vs. high; low vs. gravity flow) on re-operation within one year among patients with open fractures. Methods/Design The FLOW study is a multi-center, randomized controlled trial using a 2 × 3 factorial design. Surgeons at clinical sites in North America, Europe, Australia, and Asia will recruit 2 280 patients who will be centrally randomized into one of the 6 treatment arms (soap + low pressure; soap + gravity flow pressure; soap + high pressure; saline + low pressure; saline + gravity flow pressure; saline + high pressure). The primary outcome of the study is re-operation to promote wound or bone healing, or to treat an infection. This composite endpoint of re-operation includes a narrow spectrum of patient-important procedures: irrigation and debridement for infected wound, revision and closure for wound dehiscence, wound coverage procedures for infected or necrotic wound, bone grafts or implant exchange procedures for established nonunion in patients with postoperative fracture gaps less than 1 cm, intramedullary nail dynamizations in the operating room, and fasciotomies for compartment syndrome. Patients, outcome adjudicators, and data analysts will be blinded. We will compare rates of re-operation at

  17. Does an Open Recirculation Line Affect the Flow Rate and Pressure in a Neonatal Extracorporeal Life Support Circuit With a Centrifugal or Roller Pump?

    PubMed

    Wang, Shigang; Spencer, Shannon B; Woitas, Karl; Glass, Kristen; Kunselman, Allen R; Ündar, Akif

    2017-01-01

    The objective of this study is to evaluate the impact of an open or closed recirculation line on flow rate, circuit pressure, and hemodynamic energy transmission in simulated neonatal extracorporeal life support (ECLS) systems. The two neonatal ECLS circuits consisted of a Maquet HL20 roller pump (RP group) or a RotaFlow centrifugal pump (CP group), Quadrox-iD Pediatric oxygenator, and Biomedicus arterial and venous cannulae (8 Fr and 10 Fr) primed with lactated Ringer's solution and packed red blood cells (hematocrit 35%). Trials were conducted at flow rates ranging from 200 to 600 mL/min (200 mL/min increments) with a closed or open recirculation line at 36°C. Real-time pressure and flow data were recorded using a custom-based data acquisition system. In the RP group, the preoxygenator flow did not change when the recirculation line was open while the prearterial cannula flow decreased by 15.7-20.0% (P < 0.01). Circuit pressure, total circuit pressure drop, and hemodynamic energy delivered to patients also decreased (P < 0.01). In the CP group, the prearterial cannula flow did not change while preoxygenator flow increased by 13.6-18.8% (P < 0.01). Circuit pressure drop and hemodynamic energy transmission remained the same. The results showed that the shunt of an open recirculation line could decrease perfusion flow in patients in the ECLS circuit using a roller pump, but did not change perfusion flow in the circuit using a centrifugal pump. An additional flow sensor is needed to monitor perfusion flow in patients if any shunts exist in the ECLS circuit.

  18. Effect of methacholine on low-frequency mechanics of canine airways and lung tissue.

    PubMed

    Sato, J; Suki, B; Davey, B L; Bates, J H

    1993-07-01

    We measured tracheal flow, tracheal pressure, and alveolar capsule pressure in four anesthetized paralyzed tracheostomized open-chest dogs. Lung impedance between 0.12 and 4.88 Hz was measured with a forced volume oscillation technique before and after the intravenous administration of methacholine (MCh). Before MCh administration, lung impedance was well described by a model featuring a single airway leading to an alveolar region surrounded by tissue with a continuous distribution of viscoelastic time constants as used by Hantos et al. (J. Appl. Physiol. 68: 849-860, 1990). After MCh, however, this model gave a poor fit to the impedances. The impedances were well accounted for, however, when the model was enhanced to include an extra time constant term, which we suspect is required to account for the uneven ventilation distribution produced by MCh. Airway impedance before MCh administration was well described by a simple resistance-inertance model, but a model incorporating serial inhomogeneity of ventilation was again required after MCh. Our results support those of previous studies indicating that the impedance of the normal dog lung is well described by a homogeneously ventilated viscoelastic tissue model. In contrast, our results after MCh administration show strong evidence of marked regional ventilation inhomogeneity in addition to the rheological properties of the tissues.

  19. Development of open air silicon deposition technology by silane-free atmospheric pressure plasma enhanced chemical transport under local ambient gas control

    NASA Astrophysics Data System (ADS)

    Naito, Teruki; Konno, Nobuaki; Yoshida, Yukihisa

    2016-07-01

    Open air silicon deposition was performed by combining silane-free atmospheric pressure plasma-enhanced chemical transport and a newly developed local ambient gas control technology. The effect of air contamination on silicon deposition was investigated using a vacuum chamber, and the allowable air contamination level was confirmed to be 3 ppm. The capability of the local ambient gas control head was investigated numerically and experimentally. A safe and clean process environment with air contamination less than 1 ppm was achieved. Combining these technologies, a microcrystalline silicon film was deposited in open air, the properties of which were comparable to those of silicon films deposited in a vacuum chamber.

  20. Fluid Lavage of Open Wounds (FLOW): A Multicenter, Blinded, Factorial Trial Comparing Alternative Irrigating Solutions and Pressures in Patients with Open Fractures

    DTIC Science & Technology

    2013-10-01

    serious adverse event SF-12: Short Form-12 questionnaire SPRINT: Study to Prospectively evaluate Reamed Intramedually Nails in Patients with Tibial ...models of a contaminated tibial shaft fracture, rat models of fracture healing, and cell culture models of bone nodule formation. Our experimental...Bhandari et al, 2002; Petrisor et al, 2008) to explore surgeons’ views regarding wound irrigation. Of 577 orthopaedic surgeons managing open tibial

  1. Effect of aerosol propellants and surfactants on airway resistance

    PubMed Central

    Sterling, G. M.; Batten, J. C.

    1969-01-01

    The effects on the airways of inhalation of the vehicles used in two commercial pressurized bronchodilator aerosols were studied in 20 normal and seven asthmatic subjects. Changes in bronchial calibre due to bronchoconstriction were measured as changes in airway resistance using a constant volume whole body plethysmograph, and results were expressed as changes in the ratio Airway conductance/Thoracic gas volume (=specific airway conductance). The aerosols caused very slight bronchoconstriction in the normal subjects, with a mean decrease of 5·3% in specific airway conductance after inhalation of a spray containing sorbitol trioleate as a surface tension lowering agent, and of 9·7% after inhalation of a spray containing lecithin. This effect was prevented by prior inhalation of atropine methonitrate, and its mechanism was therefore probably a vagally mediated reflex. The bronchoconstriction was also reversed by the addition of isoprenaline to the aerosol. The asthmatic subjects showed larger mean reductions in specific airway conductance of 13% and 21% after sorbitol and lecithin respectively: the response was again prevented by atropine. We conclude that, although the aerosol vehicles cause slight bronchoconstriction, this is unlikely to be a clinical danger since it is insufficient to cause symptoms of wheezing, and is less than that caused by inhalation of a single cigarette. Moreover, the constriction is regularly converted to dilatation in both normal and asthmatic subjects by the addition of atropine or isoprenaline to the aerosol. PMID:5821624

  2. A mechanical design principle for tissue structure and function in the airway tree.

    PubMed

    LaPrad, Adam S; Lutchen, Kenneth R; Suki, Béla

    2013-01-01

    With every breath, the dynamically changing mechanical pressures must work in unison with the cells and soft tissue structures of the lung to permit air to efficiently traverse the airway tree and undergo gas exchange in the alveoli. The influence of mechanics on cell and tissue function is becoming apparent, raising the question: how does the airway tree co-exist within its mechanical environment to maintain normal cell function throughout its branching structure of diminishing dimensions? We introduce a new mechanical design principle for the conducting airway tree in which mechanotransduction at the level of cells is driven to orchestrate airway wall structural changes that can best maintain a preferred mechanical microenvironment. To support this principle, we report in vitro radius-transmural pressure relations for a range of airway radii obtained from healthy bovine lungs and model the data using a strain energy function together with a thick-walled cylinder description. From this framework, we estimate circumferential stresses and incremental Young's moduli throughout the airway tree. Our results indicate that the conducting airways consistently operate within a preferred mechanical homeostatic state, termed mechanical homeostasis, that is characterized by a narrow range of circumferential stresses and Young's moduli. This mechanical homeostatic state is maintained for all airways throughout the tree via airway wall dimensional and mechanical relationships. As a consequence, cells within the airway walls throughout the airway tree experience similar oscillatory strains during breathing that are much smaller than previously thought. Finally, we discuss the potential implications of how the maintenance of mechanical homeostasis, while facilitating healthy tissue-level alterations necessary for maturation, may lead to airway wall structural changes capable of chronic asthma.

  3. Door-opening motion can potentially lead to a transient breakdown in negative-pressure isolation conditions: the importance of vorticity and buoyancy airflows.

    PubMed

    Tang, J W; Eames, I; Li, Y; Taha, Y A; Wilson, P; Bellingan, G; Ward, K N; Breuer, J

    2005-12-01

    A patient with severe chickenpox was admitted to a negative-pressure isolation room. He remained sedated, intubated and mechanically ventilated throughout his admission. He was managed only by nurses immune to chickenpox. A non-immune male nurse occasionally handed equipment through the doorway, without entering the room. Ten days later, he also developed chickenpox. Sequencing of viruses from the patient and nurse showed the same rare genotype, indicating nosocomial transmission. An experimental model demonstrated that, despite negative pressure, opening the door could have resulted in transport of infectious air out of the isolation room, leading to a breakdown in isolation conditions.

  4. Inspiratory work and response times of a modified pediatric volume ventilator during synchronized intermittent mandatory ventilation and pressure support ventilation.

    PubMed

    Martin, L D; Rafferty, J F; Wetzel, R C; Gioia, F R

    1989-12-01

    Volume ventilation by demand flow ventilators significantly increases work of breathing during inspiration. Although various ventilator modifications and different modes of ventilation have been developed, there have been few studies regarding imposed work of breathing in infants and children. This study was designed to evaluate several modifications of a commercially available demand flow ventilator designed to shorten response time (tr) and decrease the imposed work (Wi) involved in opening the demand valve. Minimum withdrawal volume (Vmin), maximum negative pressure (P mneg), and tr were measured. Wi was defined as the product of Vmin and P mneg. Seven Siemens Servo 900C ventilators were tested under 16 different trial conditions with four variables: 1) mode of ventilation (synchronized intermittent mandatory ventilation [SIMV] vs. pressure support ventilation [PSV]); 2) caliber of circuit tubing (adult vs. pediatric); 3) location of airway pressure monitor (distal vs. proximal); and 4) ventilator trigger sensitivity (0 cm H2O--high vs. -2 cm H2O--low). Vmin, Pmneg, and Wi were all decreased (P less than .05) while tr was unaffected by changing ventilator trigger sensitivity from low to high. Wi was decreased by pediatric tubing and proximal airway pressure monitoring only when low trigger sensitivity was used. PSV and proximal airway monitoring shortened tr. The authors conclude that the use of pediatric circuit tubing and proximal airway pressure monitoring with a Siemens Servo 900C ventilator significantly improved ventilator performance.

  5. Open tibial fractures grade IIIC treated successfully with external fixation, negative-pressure wound therapy and recombinant human bone morphogenetic protein 7.

    PubMed

    Babiak, Ireneusz

    2014-10-01

    The aim of the therapy in open tibial fractures grade III was to cover the bone with soft tissue and achieve healed fracture without persistent infection. Open tibial fractures grade IIIC with massive soft tissue damage require combined orthopaedic, vascular and plastic-reconstructive procedures. Negative-pressure wound therapy (NPWT), used in two consecutive cases with open fracture grade IIIC of the tibia diaphysis, healed extensive soft tissue defect with exposure of the bone. NPWT eventually allowed for wound closure by split skin graft within 21-25 days. Ilizarov external fixator combined with application of recombinant human bone morphogenetic protein-7 at the site of delayed union enhanced definitive bone healing within 16-18 months.

  6. Low-Pressure Burst-Mode Focused Ultrasound Wave Reconstruction and Mapping for Blood-Brain Barrier Opening: A Preclinical Examination

    PubMed Central

    Xia, Jingjing; Tsui, Po-Hsiang; Liu, Hao-Li

    2016-01-01

    Burst-mode focused ultrasound (FUS) exposure has been shown to induce transient blood-brain barrier (BBB) opening for potential CNS drug delivery. FUS-BBB opening requires imaging guidance during the intervention, yet current imaging technology only enables postoperative outcome confirmation. In this study, we propose an approach to visualize short-burst low-pressure focal beam distribution that allows to be applied in FUS-BBB opening intervention on small animals. A backscattered acoustic-wave reconstruction method based on synchronization among focused ultrasound emission, diagnostic ultrasound receiving and passively beamformed processing were developed. We observed that focal beam could be successfully visualized for in vitro FUS exposure with 0.5–2 MHz without involvement of microbubbles. The detectable level of FUS exposure was 0.467 MPa in pressure and 0.05 ms in burst length. The signal intensity (SI) of the reconstructions was linearly correlated with the FUS exposure level both in-vitro (r2 = 0.9878) and in-vivo (r2 = 0.9943), and SI level of the reconstructed focal beam also correlated with the success and level of BBB-opening. The proposed approach provides a feasible way to perform real-time and closed-loop control of FUS-based brain drug delivery. PMID:27295608

  7. Low-Pressure Burst-Mode Focused Ultrasound Wave Reconstruction and Mapping for Blood-Brain Barrier Opening: A Preclinical Examination

    NASA Astrophysics Data System (ADS)

    Xia, Jingjing; Tsui, Po-Hsiang; Liu, Hao-Li

    2016-06-01

    Burst-mode focused ultrasound (FUS) exposure has been shown to induce transient blood-brain barrier (BBB) opening for potential CNS drug delivery. FUS-BBB opening requires imaging guidance during the intervention, yet current imaging technology only enables postoperative outcome confirmation. In this study, we propose an approach to visualize short-burst low-pressure focal beam distribution that allows to be applied in FUS-BBB opening intervention on small animals. A backscattered acoustic-wave reconstruction method based on synchronization among focused ultrasound emission, diagnostic ultrasound receiving and passively beamformed processing were developed. We observed that focal beam could be successfully visualized for in vitro FUS exposure with 0.5–2 MHz without involvement of microbubbles. The detectable level of FUS exposure was 0.467 MPa in pressure and 0.05 ms in burst length. The signal intensity (SI) of the reconstructions was linearly correlated with the FUS exposure level both in-vitro (r2 = 0.9878) and in-vivo (r2 = 0.9943), and SI level of the reconstructed focal beam also correlated with the success and level of BBB-opening. The proposed approach provides a feasible way to perform real-time and closed-loop control of FUS-based brain drug delivery.

  8. A dose-response curve for the negative bias pressure of an intrathoracic pressure regulator during CPR.

    PubMed

    Babbs, Charles F; Yannopoulos, Demetris

    2006-12-01

    An intrathoracic pressure regulator (ITPR) is a device that can be added to the external end of a tracheal tube to create controlled negative airway pressure between positive pressure ventilations. The resulting downward bias of the airway pressure baseline promotes increased venous return and enhanced circulation during CPR and also during hypovolemic shock. In the present study, we exercised a mathematical model of the human cardiopulmonary system, including airways, lungs, a four chambered heart, great vessels, peripheral vascular beds, and the biomechanics of chest compression and recoil, to determine the relationship between systemic perfusion pressure during CPR and the value of baseline negative airway pressure in an ITPR. Perfusion pressure increases approximately 50% as baseline airway pressure falls from zero to -10 cm H2O. Thereafter perfusion pressure plateaus. Negative bias pressures exceeding -10 cm H2O are not needed in ITPR-CPR.

  9. Operative endoscopy of the airway

    PubMed Central

    Walters, Dustin M.

    2016-01-01

    Airway endoscopy has long been an important and useful tool in the management of thoracic diseases. As thoracic specialists have gained experience with both flexible and rigid bronchoscopic techniques, the technology has continued to evolve so that bronchoscopy is currently the foundation for diagnosis and treatment of many thoracic ailments. Airway endoscopy plays a significant role in the biopsy of tumors within the airways, mediastinum, and lung parenchyma. Endoscopic methods have been developed to treat benign and malignant airway stenoses and tracheomalacia. And more recently, techniques have been conceived to treat end-stage emphysema and prolonged air leaks in select patients. This review describes the abundant uses of airway endoscopy, as well as technical considerations and limitations of the current technologies. PMID:26981263

  10. Global airway disease beyond allergy.

    PubMed

    Hellings, Peter W; Prokopakis, Emmanuel P

    2010-03-01

    Besides the anatomic continuity of the upper and lower airways, inflammation in one part of the airway influences the homeostasis of the other. The mechanisms underlying this interaction have been studied primarily in allergic disease, showing systemic immune activation, induction of inflammation at a distance, and a negative impact of nasal inflammation on bronchial homeostasis. In addition to allergy, other inflammatory conditions of the upper airways are associated with lower airway disease. Rhinosinusitis is frequently associated with asthma and chronic obstructive pulmonary disease. The impairment of purification, humidification, and warming up of the inspired air by the nose in rhinosinusitis may be responsible in part for bronchial pathology. The resolution of sinonasal inflammation via medical and/or surgical treatment is responsible for the beneficial effect of the treatment on bronchial disease. This article provides a comprehensive overview of the current knowledge of upper and lower airway communication beyond allergic disease.

  11. Recurrent airway obstruction: a review.

    PubMed

    Pirie, R S

    2014-05-01

    Recurrent airway obstruction is a widely recognised airway disorder, characterised by hypersensitivity-mediated neutrophilic airway inflammation and lower airway obstruction in a subpopulation of horses when exposed to suboptimal environments high in airborne organic dust. Over the past decade, numerous studies have further advanced our understanding of different aspects of the disease. These include clarification of the important inhaled airborne agents responsible for disease induction, improving our understanding of the underlying genetic basis of disease susceptibility and unveiling the fundamental immunological mechanisms leading to establishment of the classic disease phenotype. This review, as well as giving a clinical overview of recurrent airway obstruction, summarises much of the work in these areas that have culminated in a more thorough understanding of this debilitating disease.

  12. The airway microbiome and disease.

    PubMed

    Marsland, Benjamin J; Yadava, Koshika; Nicod, Laurent P

    2013-08-01

    Although traditionally thought to be sterile, accumulating evidence now supports the concept that our airways harbor a microbiome. Thus far, studies have focused upon characterizing the bacterial constituents of the airway microbiome in both healthy and diseased lungs, but what perhaps provides the greatest impetus for the exploration of the airway microbiome is that different bacterial phyla appear to dominate diseased as compared with healthy lungs. As yet, there is very limited evidence supporting a functional role for the airway microbiome, but continued research in this direction is likely to provide such evidence, particularly considering the progress that has been made in understanding host-microbe mutualism in the intestinal tract. In this review, we highlight the major advances that have been made discovering and describing the airway microbiome, discuss the experimental evidence that supports a functional role for the microbiome in health and disease, and propose how this emerging field is going to impact clinical practice.

  13. Effect of Exit-Slot Position and Opening on the Available Cooling Pressure for NACA Nose-Slot Cowlings

    NASA Technical Reports Server (NTRS)

    Stickle, George W; Naiman, Irven; Crigler, John L

    1940-01-01

    Report presents the results of an investigation of full-scale nose-slot cowlings conducted in the NACA 20-foot wind tunnel to furnish information on the pressure drop available for cooling. Engine conductances from 0 to 0.12 and exit-slot conductances from 0 to 0.30 were covered. Two basic nose shapes were tested to determine the effect of the radius of curvature of the nose contour; the nose shape with the smaller radius of curvature gave the higher pressure drop across the engine. The best axial location of the slot for low-speed operation was found to be in the region of maximum negative pressure for the basic shape for the particular operating condition. The effect of the pressure operating condition on the available cooling pressure is shown.

  14. Pressure fluctuation prediction of a model pump turbine at no load opening by a nonlinear k-ε turbulence model

    NASA Astrophysics Data System (ADS)

    Liu, J. T.; Zuo, Z. G.; Liu, S. H.; Wu, Y. L.

    2014-03-01

    In this paper, a new nonlinear k-ε turbulence model based on RNG k-ε turbulence model and Wilcox's k-ω turbulence model was proposed to simulate the unsteady flow and to predict the pressure fluctuation through a model pump turbine for engineering application. Calculations on a curved rectangular duct proved that the nonlinear k-ε turbulence model is applicable for high pressure gradient flows and large curvature flows. The numerically predicted relative pressure amplitude (peak to peak) in time domain to the pump turbine head at no load condition is very close to the experimental data. It is indicated that the prediction of the pressure fluctuation is valid by the present nonlinear k-ε method. The high pressure fluctuation in this area is the main issue for pump turbine design, especially at high head condition.

  15. Management of Septic Open Abdomen in a Morbid Obese Patient with Enteroatmospheric Fistula by Using Standard Abdominal Negative Pressure Therapy in Conjunction with Intrarectal One

    PubMed Central

    Yetisir, Fahri; Salman, A. Ebru; Acar, Hasan Zafer; Özer, Mehmet; Aygar, Muhittin; Osmanoglu, Gokhan

    2015-01-01

    Introduction. Management of open abdomen (OA) with enteroatmospheric fistula (EAF) in morbid obese patient with comorbid disease is challenging. We would like to report the management of septic OA in morbid obese patient with EAF which developed after strangulated recurrent giant incisional hernia repair. We would also like to emphasize, in this case, the conversion of EAF to ileostomy by the help of second Negative Pressure Therapy (NPT) on ostomy side, and the chance of new EAF occurrence was reduced with intrarectal NPT. Case Presentation. 62-year-old morbid obese woman became an OA patient with EAF after strangulated recurrent giant hernia. EAF was converted to ostomy with pezzer drain by the help of second NPT on ostomy. Colonic distention was reduced with the third NPT application via rectum. Abdominal reapproximation anchor (ABRA) system was used for delayed abdominal closure. Conclusions. Using the 2nd NPT on ostomy side may help in the maturation of the ostomy created in a difficult condition in an open abdomen. Using the 3rd NPT through rectum may decrease the chance of EAF formation by reducing the pressure difference between intraluminal pressure and extraluminal pressure in hollow viscera. PMID:26779360

  16. The importance of synergy between deep inspirations and fluidization in reversing airway closure.

    PubMed

    Donovan, Graham M; Sneyd, James; Tawhai, Merryn H

    2012-01-01

    Deep inspirations (DIs) and airway smooth muscle fluidization are two widely studied phenomena in asthma research, particularly for their ability (or inability) to counteract severe airway constriction. For example, DIs have been shown effectively to reverse airway constriction in normal subjects, but this is impaired in asthmatics. Fluidization is a connected phenomenon, wherein the ability of airway smooth muscle (ASM, which surrounds and constricts the airways) to exert force is decreased by applied strain. A maneuver which sufficiently strains the ASM, then, such as a DI, is thought to reduce the force generating capacity of the muscle via fluidization and hence reverse or prevent airway constriction. Understanding these two phenomena is considered key to understanding the pathophysiology of asthma and airway hyper-responsiveness, and while both have been extensively studied, the mechanism by which DIs fail in asthmatics remains elusive. Here we show for the first time the synergistic interaction between DIs and fluidization which allows the combination to provide near complete reversal of airway closure where neither is effective alone. This relies not just on the traditional model of airway bistability between open and closed states, but also the critical addition of previously-unknown oscillatory and chaotic dynamics. It also allows us to explore the types of subtle change which can cause this interaction to fail, and thus could provide the missing link to explain DI failure in asthmatics.

  17. Evaluation of Capiox FX05 oxygenator with an integrated arterial filter on trapping gaseous microemboli and pressure drop with open and closed purge line.

    PubMed

    Qiu, Feng; Peng, Sophia; Kunselman, Allen; Ündar, Akif

    2010-11-01

    Gaseous microemboli (GME) remain a challenge for cardiopulmonary bypass (CPB) because there is a positive correlation between microemboli exposure during CPB and postoperative neurological injury. Thus, minimizing the number of GME delivered to pediatric patients undergoing CPB procedures would lead to better clinical outcomes. In this study, we used a simulated CPB model to evaluate the effectiveness of capturing GME and the degree of membrane pressure drop for a new membrane oxygenator, Capiox Baby FX05 (Terumo Corporation,Tokyo, Japan), which has an integrated arterial filter with open and closed purge line.We used identical components in this study as our clinical CPB circuit. Three emboli detection and classification quantifier transducers were placed at prepump, preoxygenator, and postoxygenator sites in the circuit.Two flow probes as well as three pressure transducers were placed upstream and downstream of the oxygenator. The system was primed with human blood titrated to 30% hematocrit with Lactated Ringer’s solution.A bolus of air (1 mL) was injected in the prepump site under nonpulsatile perfusion mode at three flow rates (500,750, and 1000 mL/min) and with the purge line either open or closed. Six trials were performed for each unique set-up for a total of 36 trials.All trials were conducted at 35°C. The circuit pressure was kept constant at 100 mm Hg. Both the size and quantity of microemboli detected at postoxygenator site were recorded for 5 min postair injection. It was found that total counts of GME were significantly reduced with the purge line open when compared to keeping the purge line closed (P < 0.0001 at 1000 mL/min). At all flow rates, most of the GME were under 20 microns in size. In terms of microemboli greater than 40 microns, the counts were significantly higher with the purge line closed compared to keeping the purge line open at flow rates of 750 mL/min and 1000 mL/min (P < 0.01). At all flow rates,there is a tiny difference of less

  18. Hyperresponsiveness in the human nasal airway: new targets for the treatment of allergic airway disease.

    PubMed Central

    Turner, P J; Foreman, J C

    1999-01-01

    Allergic rhinitis is a condition which affects over 15% of the population in the United Kingdom. The pathological process involves two stages: nasal inflammation, and the development of nasal airway hyperresponsiveness (AHR) to allergen and a number of other stimuli. This results in the amplification of any subsequent allergic reaction, contributing to the chronic allergic state. A number of different hypotheses have been proposed to explain the underlying mechanism of AHR, including a role for eosinophil-derived proteins, free radicals and neuropeptides. While there may be a number of independent pathways which can result in AHR, evidence obtained from both animal models and in vivo experiments in humans indicate that some mediators may interact with one another, resulting in AHR. Further research into these interactions may open new avenues for the pharmacological treatment of chronic allergic rhinitis, and possibly other allergic airway diseases. PMID:10704051

  19. Using optical coherence tomography (OCT) imaging in the evaluation of airway dynamics (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Szabari, Margit V.; Kelly, Vanessa J.; Applegate, Matthew B.; Chee, Chunmin; Tan, Khay M.; Hariri, Lida P.; Harris, R. Scott; Winkler, Tilo; Suter, Melissa J.

    2016-03-01

    Asthma is a chronic disease resulting in periodic attacks of coughing and wheezing due to temporarily constricted and clogged airways. The pathophysiology of asthma and the process of airway narrowing are not completely understood. Appropriate in vivo imaging modality with sufficient spatial and temporal resolution to dynamically assess the behavior of airways is missing. Optical coherence tomography (OCT) enables real-time evaluation of the airways during dynamic and static breathing maneuvers. Our aim was to visualize the structure and function of airways in healthy and Methacholine (MCh) challenged lung. Sheep (n=3) were anesthetized, mechanically ventilated and imaged with OCT in 4 dependent and 4 independent airways both pre- and post-MCh administration. The OCT system employed a 2.4 Fr (0.8 mm diameter) catheter and acquired circumferential cross-sectional images in excess of 100 frames per second during dynamic tidal breathing, 20 second static breath-holds at end-inspiration and expiration pressure, and in a response to a single deep inhalation. Markedly different airway behavior was found in dependent versus non-dependent airway segments before and after MCh injection. OCT is a non-ionizing light-based imaging modality, which may provide valuable insight into the complex dynamic behavior of airway structure and function in the normal and asthmatic lung.

  20. Computational analysis of microbubble flows in bifurcating airways: role of gravity, inertia, and surface tension.

    PubMed

    Chen, Xiaodong; Zielinski, Rachel; Ghadiali, Samir N

    2014-10-01

    Although mechanical ventilation is a life-saving therapy for patients with severe lung disorders, the microbubble flows generated during ventilation generate hydrodynamic stresses, including pressure and shear stress gradients, which damage the pulmonary epithelium. In this study, we used computational fluid dynamics to investigate how gravity, inertia, and surface tension influence both microbubble flow patterns in bifurcating airways and the magnitude/distribution of hydrodynamic stresses on the airway wall. Direct interface tracking and finite element techniques were used to simulate bubble propagation in a two-dimensional (2D) liquid-filled bifurcating airway. Computational solutions of the full incompressible Navier-Stokes equation were used to investigate how inertia, gravity, and surface tension forces as characterized by the Reynolds (Re), Bond (Bo), and Capillary (Ca) numbers influence pressure and shear stress gradients at the airway wall. Gravity had a significant impact on flow patterns and hydrodynamic stress magnitudes where Bo > 1 led to dramatic changes in bubble shape and increased pressure and shear stress gradients in the upper daughter airway. Interestingly, increased pressure gradients near the bifurcation point (i.e., carina) were only elevated during asymmetric bubble splitting. Although changes in pressure gradient magnitudes were generally more sensitive to Ca, under large Re conditions, both Re and Ca significantly altered the pressure gradient magnitude. We conclude that inertia, gravity, and surface tension can all have a significant impact on microbubble flow patterns and hydrodynamic stresses in bifurcating airways.

  1. [Acute pulmonary edema secondary to acute upper airway obstruction].

    PubMed

    Sánchez-Ortega, J L; Carpintero-Moreno, F; Olivares-López, A; Borrás-Rubio, E; Alvarez-López, M J; García-Izquierdo, A

    1992-01-01

    We report a 72 years old woman with mild arterial hypertension and no other pathological history who presented an acute pulmonary edema due to acute obstruction of the upper airway secondary to vocal chord paralysis developing during the immediate postoperative phase of thyroidectomy. The acute pulmonary edema resolved after application of tracheal reintubation, mechanical ventilation controlled with end expiratory positive pressure, diuretics, morphine, and liquid restriction. We discuss the possible etiopathogenic possibilities of this infrequent clinical picture and we suggest that all patients who suffered and acute obstruction of the upper airways require a careful clinical surveillance in order to prevent the development of the pulmonary syndrome.

  2. Negative-Pressure Pulmonary Edema.

    PubMed

    Bhattacharya, Mallar; Kallet, Richard H; Ware, Lorraine B; Matthay, Michael A

    2016-10-01

    Negative-pressure pulmonary edema (NPPE) or postobstructive pulmonary edema is a well-described cause of acute respiratory failure that occurs after intense inspiratory effort against an obstructed airway, usually from upper airway infection, tumor, or laryngospasm. Patients with NPPE generate very negative airway pressures, which augment transvascular fluid filtration and precipitate interstitial and alveolar edema. Pulmonary edema fluid collected from most patients with NPPE has a low protein concentration, suggesting hydrostatic forces as the primary mechanism for the pathogenesis of NPPE. Supportive care should be directed at relieving the upper airway obstruction by endotracheal intubation or cricothyroidotomy, institution of lung-protective positive-pressure ventilation, and diuresis unless the patient is in shock. Resolution of the pulmonary edema is usually rapid, in part because alveolar fluid clearance mechanisms are intact. In this review, we discuss the clinical presentation, pathophysiology, and management of negative-pressure or postobstructive pulmonary edema.

  3. Putting the Squeeze on Airway Epithelia

    PubMed Central

    Park, Jin-Ah; Fredberg, Jeffrey J.

    2015-01-01

    Asthma is characterized by chronic inflammation, airway hyperresponsiveness, and progressive airway remodeling. The airway epithelium is known to play a critical role in the initiation and perpetuation of these processes. Here, we review how excessive epithelial stress generated by bronchoconstriction is sufficient to induce airway remodeling, even in the absence of inflammatory cells. PMID:26136543

  4. Surface fluid absorption and secretion in small airways

    PubMed Central

    Shamsuddin, A K M; Quinton, P M

    2012-01-01

    Native small airways must remain wet enough to be pliable and support ciliary clearance, but dry enough to remain patent for gas flow. The airway epithelial lining must both absorb and secrete ions to maintain a critical level of fluid on its surface. Despite frequent involvement in lung diseases, the minuscule size has limited studies of peripheral airways. To meet this challenge, we used a capillary to construct an Ussing chamber (area <1 mm2) to measure electrolyte transport across small native airways (∼1 mm ø) from pig lung. Transepithelial potentials (Vt) were recorded in open circuit conditions while applying constant current pulses across the luminal surface of dissected airways to calculate transepithelial electrical conductance (Gt) and equivalent short circuit current () in the presence and absence of selected Na+ and Cl− transport inhibitors (amiloride, GlyH-101, Niflumic acid) and agonists (Forskolin + IBMX, UTP). Considered together the responses suggest an organ composed of both secreting and absorbing epithelia that constitutively and concurrently transport fluids into and out of the airway, i.e. in opposite directions. Since the epithelial lining of small airways is arranged in long, accordion-like rows of pleats and folds that run axially down the lumen, we surmise that cells within the pleats are mainly secretory while the cells of the folds are principally absorptive. This structural arrangement could provide local fluid transport from within the pleats toward the luminal folds that may autonomously regulate the local surface fluid volume for homeostasis while permitting acute responses to maintain clearance. PMID:22547637

  5. 7. EXTERIOR VIEW OF BALTIMORE FAN HOUSE, AIRWAY, AND HILLMAN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. EXTERIOR VIEW OF BALTIMORE FAN HOUSE, AIRWAY, AND HILLMAN FAN HOUSE LOOKING SOUTHEAST The roof of the 1908 Baltimore Fan House is to the left; the doorway opens onto the rear of the metal fan housing. In the immediate foreground is a section of the blast doors installed in the airway directly over the shaft to protect the fans in case of a mine explosion. The sloping airway, to the right, connects with the New Fan House, whose metal updraft chimney is evident in the right background. The engine house of the Hillman Fan House is in the left background with the fan housing and updraft chimney connected. The boiler house stack is in the background. All of the engines in the fan complex were powered by the boiler house. - Dorrance Colliery Fan Complex, South side of Susquehanna River at Route 115 & Riechard Street, Wilkes-Barre, Luzerne County, PA

  6. The GABAA agonist muscimol attenuates induced airway constriction in guinea pigs in vivo.

    PubMed

    Gleason, Neil R; Gallos, George; Zhang, Yi; Emala, Charles W

    2009-04-01

    GABA(A) channels are ubiquitously expressed on neuronal cells and act via an inward chloride current to hyperpolarize the cell membrane of mature neurons. Expression and function of GABA(A) channels on airway smooth muscle cells has been demonstrated in vitro. Airway smooth muscle cell membrane hyperpolarization contributes to relaxation. We hypothesized that muscimol, a selective GABA(A) agonist, could act on endogenous GABA(A) channels expressed on airway smooth muscle to attenuate induced increases in airway pressures in anesthetized guinea pigs in vivo. In an effort to localize muscimol's effect to GABA(A) channels expressed on airway smooth muscle, we pretreated guinea pigs with a selective GABA(A) antagonist (gabazine) or eliminated lung neural control from central parasympathetic, sympathetic, and nonadrenergic, noncholinergic (NANC) nerves before muscimol treatment. Pretreatment with intravenous muscimol alone attenuated intravenous histamine-, intravenous acetylcholine-, or vagal nerve-stimulated increases in peak pulmonary inflation pressure. Pretreatment with the GABA(A) antagonist gabazine blocked muscimol's effect. After the elimination of neural input to airway tone by central parasympathetic nerves, peripheral sympathetic nerves, and NANC nerves, intravenous muscimol retained its ability to block intravenous acetylcholine-induced increases in peak pulmonary inflation pressures. These findings demonstrate that the GABA(A) agonist muscimol acting specifically via GABA(A) channel activation attenuates airway constriction independently of neural contributions. These findings suggest that therapeutics directed at the airway smooth muscle GABA(A) channel may be a novel therapy for airway constriction following airway irritation and possibly more broadly in diseases such as asthma and chronic obstructive pulmonary disease.

  7. Computational Flow Modeling of Human Upper Airway Breathing

    NASA Astrophysics Data System (ADS)

    Mylavarapu, Goutham

    Computational modeling of biological systems have gained a lot of interest in biomedical research, in the recent past. This thesis focuses on the application of computational simulations to study airflow dynamics in human upper respiratory tract. With advancements in medical imaging, patient specific geometries of anatomically accurate respiratory tracts can now be reconstructed from Magnetic Resonance Images (MRI) or Computed Tomography (CT) scans, with better and accurate details than traditional cadaver cast models. Computational studies using these individualized geometrical models have advantages of non-invasiveness, ease, minimum patient interaction, improved accuracy over experimental and clinical studies. Numerical simulations can provide detailed flow fields including velocities, flow rates, airway wall pressure, shear stresses, turbulence in an airway. Interpretation of these physical quantities will enable to develop efficient treatment procedures, medical devices, targeted drug delivery etc. The hypothesis for this research is that computational modeling can predict the outcomes of a surgical intervention or a treatment plan prior to its application and will guide the physician in providing better treatment to the patients. In the current work, three different computational approaches Computational Fluid Dynamics (CFD), Flow-Structure Interaction (FSI) and Particle Flow simulations were used to investigate flow in airway geometries. CFD approach assumes airway wall as rigid, and relatively easy to simulate, compared to the more challenging FSI approach, where interactions of airway wall deformations with flow are also accounted. The CFD methodology using different turbulence models is validated against experimental measurements in an airway phantom. Two case-studies using CFD, to quantify a pre and post-operative airway and another, to perform virtual surgery to determine the best possible surgery in a constricted airway is demonstrated. The unsteady

  8. Airway complications after lung transplantation.

    PubMed

    Machuzak, Michael; Santacruz, Jose F; Gildea, Thomas; Murthy, Sudish C

    2015-01-01

    Airway complications after lung transplantation present a formidable challenge to the lung transplant team, ranging from mere unusual images to fatal events. The exact incidence of complications is wide-ranging depending on the type of event, and there is still evolution of a universal characterization of the airway findings. Management is also wide-ranging. Simple observation or simple balloon bronchoplasty is sufficient in many cases, but vigilance following more severe necrosis is required for late development of both anastomotic and nonanastomotic airway strictures. Furthermore, the impact of coexisting infection, rejection, and medical disease associated with high-level immunosuppression further complicates care.

  9. Gene Delivery to the Airway

    PubMed Central

    Keiser, Nicholas W.; Engelhardt, John F.

    2013-01-01

    This unit describes generation of and gene transfer to several commonly used airway models. Isolation and transduction of primary airway epithelial cells are first described. Next, the preparation of polarized airway epithelial monolayers is outlined. Transduction of these polarized cells is also described. Methods are presented for generation of tracheal xenografts as well as both ex vivo and in vivo gene transfer to these xenografts. Finally, a method for in vivo gene delivery to the lungs of rodents is included. Methods for evaluating transgene expression are given in the support protocols. PMID:23853081

  10. A new real time tsunami detection algorithm for bottom pressure measurements in open ocean: characterization and benchmarks

    NASA Astrophysics Data System (ADS)

    Embriaco, D.; Chierici, F.; Pignagnoli, L.

    2009-04-01

    In the last decades the use of the Bottom Pressure Recorder (BPR) in a deep ocean environment for tsunami detection has had a relevant development. A key role for an early warning system based on BPRs is played by the tsunami detection algorithms running in real time on the BPR itself or at installation site. We present a new algorithm for tsunami detection that is based on real time pressure data analysis, consisting in tide removing, spike removing, low pass filtering and linear prediction: the output is then matched against a given pressure threshold allowing the detection of anomalous events. Different configurations of the algorithm, consisting for instance in a real time band pass filtering of the pressure signal in place of linear prediction, are also tested for comparison. The algorithm is designed to be used in an autonomous early warning system, with a finite set of input parameters that can be reconfigured in real time. A realistic benchmark scheme is developed in order to characterize the algorithm features with particular regards to false alarm probability, sensitivity to the amplitude and wavelength of the tsunami and detection earliness. The algorithm behaviour in real operation is numerically estimated performing statistical simulations where a large number of synthetic tsunami waves with various amplitude, period, shape and phase is generated and superimposed to time series of real pressure data recorded in different environmental conditions and locations.

  11. Rationale and study design of ViPS – variable pressure support for weaning from mechanical ventilation: study protocol for an international multicenter randomized controlled open trial

    PubMed Central

    2013-01-01

    Background In pressure support ventilation (PSV), a non-variable level of pressure support is delivered by the ventilator when triggered by the patient. In contrast, variable PSV delivers a level of pressure support that varies in a random fashion, introducing more physiological variability to the respiratory pattern. Experimental studies show that variable PSV improves gas exchange, reduces lung inflammation and the mean pressure support, compared to non-variable PSV. Thus, it can theoretically shorten weaning from the mechanical ventilator. Methods/design The ViPS (variable pressure support) trial is an international investigator-initiated multicenter randomized controlled open trial comparing variable vs. non-variable PSV. Adult patients on controlled mechanical ventilation for more than 24 hours who are ready to be weaned are eligible for the study. The randomization sequence is blocked per center and performed using a web-based platform. Patients are randomly assigned to one of the two groups: variable PSV or non-variable PSV. In non-variable PSV, breath-by-breath pressure support is kept constant and targeted to achieve a tidal volume of 6 to 8 ml/kg. In variable PSV, the mean pressure support level over a specific time period is targeted at the same mean tidal volume as non-variable PSV, but individual levels vary randomly breath-by-breath. The primary endpoint of the trial is the time to successful weaning, defined as the time from randomization to successful extubation. Discussion ViPS is the first randomized controlled trial investigating whether variable, compared to non-variable PSV, shortens the duration of weaning from mechanical ventilation in a mixed population of critically ill patients. This trial aims to determine the role of variable PSV in the intensive care unit. Trial registration clinicaltrials.gov NCT01769053 PMID:24176188

  12. Airway management of patients with traumatic brain injury/C-spine injury

    PubMed Central

    2015-01-01

    Traumatic brain injury (TBI) is usually combined with cervical spine (C-spine) injury. The possibility of C-spine injury is always considered when performing endotracheal intubation in these patients. Rapid sequence intubation is recommended with adequate sedative or analgesics and a muscle relaxant to prevent an increase in intracranial pressure during intubation in TBI patients. Normocapnia and mild hyperoxemia should be maintained to prevent secondary brain injury. The manual-in-line-stabilization (MILS) technique effectively lessens C-spine movement during intubation. However, the MILS technique can reduce mouth opening and lead to a poor laryngoscopic view. The newly introduced video laryngoscope can manage these problems. The AirWay Scope® (AWS) and AirTraq laryngoscope decreased the extension movement of C-spines at the occiput-C1 and C2-C4 levels, improving intubation conditions and shortening the time to complete tracheal intubation compared with a direct laryngoscope. The Glidescope® also decreased cervical movement in the C2-C5 levels during intubation and improved vocal cord visualization, but a longer duration was required to complete intubation compared with other devices. A lightwand also reduced cervical motion across all segments. A fiberoptic bronchoscope-guided nasal intubation is the best method to reduce cervical movement, but a skilled operator is required. In conclusion, a video laryngoscope assists airway management in TBI patients with C-spine injury. PMID:26045922

  13. Airway management of patients with traumatic brain injury/C-spine injury.

    PubMed

    Jung, Jin Yong

    2015-06-01

    Traumatic brain injury (TBI) is usually combined with cervical spine (C-spine) injury. The possibility of C-spine injury is always considered when performing endotracheal intubation in these patients. Rapid sequence intubation is recommended with adequate sedative or analgesics and a muscle relaxant to prevent an increase in intracranial pressure during intubation in TBI patients. Normocapnia and mild hyperoxemia should be maintained to prevent secondary brain injury. The manual-in-line-stabilization (MILS) technique effectively lessens C-spine movement during intubation. However, the MILS technique can reduce mouth opening and lead to a poor laryngoscopic view. The newly introduced video laryngoscope can manage these problems. The AirWay Scope® (AWS) and AirTraq laryngoscope decreased the extension movement of C-spines at the occiput-C1 and C2-C4 levels, improving intubation conditions and shortening the time to complete tracheal intubation compared with a direct laryngoscope. The Glidescope® also decreased cervical movement in the C2-C5 levels during intubation and improved vocal cord visualization, but a longer duration was required to complete intubation compared with other devices. A lightwand also reduced cervical motion across all segments. A fiberoptic bronchoscope-guided nasal intubation is the best method to reduce cervical movement, but a skilled operator is required. In conclusion, a video laryngoscope assists airway management in TBI patients with C-spine injury.

  14. United airway disease: current perspectives

    PubMed Central

    Giavina-Bianchi, Pedro; Aun, Marcelo Vivolo; Takejima, Priscila; Kalil, Jorge; Agondi, Rosana Câmara

    2016-01-01

    Upper and lower airways are considered a unified morphological and functional unit, and the connection existing between them has been observed for many years, both in health and in disease. There is strong epidemiologic, pathophysiologic, and clinical evidence supporting an integrated view of rhinitis and asthma: united airway disease in the present review. The term “united airway disease” is opportune, because rhinitis and asthma are chronic inflammatory diseases of the upper and lower airways, which can be induced by allergic or nonallergic reproducible mechanisms, and present several phenotypes. Management of rhinitis and asthma must be jointly carried out, leading to better control of both diseases, and the lessons of the Allergic Rhinitis and Its Impact on Asthma initiative cannot be forgotten. PMID:27257389

  15. Apoptosis and the Airway Epithelium

    PubMed Central

    White, Steven R.

    2011-01-01

    The airway epithelium functions as a barrier and front line of host defense in the lung. Apoptosis or programmed cell death can be elicited in the epithelium as a response to viral infection, exposure to allergen or to environmental toxins, or to drugs. While apoptosis can be induced via activation of death receptors on the cell surface or by disruption of mitochondrial polarity, epithelial cells compared to inflammatory cells are more resistant to apoptotic stimuli. This paper focuses on the response of airway epithelium to apoptosis in the normal state, apoptosis as a potential regulator of the number and types of epithelial cells in the airway, and the contribution of epithelial cell apoptosis in important airways diseases. PMID:22203854

  16. Extraglottic airway devices: A review

    PubMed Central

    Ramaiah, Ramesh; Das, Debasmita; Bhananker, Sanjay M; Joffe, Aaron M

    2014-01-01

    Extraglottic airway devices (EAD) have become an integral part of anesthetic care since their introduction into clinical practice 25 years ago and have been used safely hundreds of millions of times, worldwide. They are an important first option for difficult ventilation during both in-hospital and out-of-hospital difficult airway management and can be utilized as a conduit for tracheal intubation either blindly or assisted by another technology (fiberoptic endoscopy, lightwand). Thus, the EAD may be the most versatile single airway technique in the airway management toolbox. However, despite their utility, knowledge regarding specific devices and the supporting data for their use is of paramount importance to patient's safety. In this review, number of commercially available EADs are discussed and the reported benefits and potential pitfalls are highlighted. PMID:24741502

  17. Improved control of blood pressure and albuminuria among patients with type-2 diabetes in Finnish open care.

    PubMed

    Varis, Juha; Metsärinne, Kaj; Koivisto, Veikko; Niskanen, Leo; Rissanen, Aila; Virkamäki, Antti; Appelroth, Tina; Pöntynen, Nora; Poussa, Tuija; Kantola, Ilkka

    2017-04-01

    Risk of cardiovascular events within the diabetic population has decreased and survival increased with patients living longer and thus facing the development of end-stage renal disease (ESRD). This calls for good care of patient with diabetes with a focus on hypertension. Patient data were collected from 42 Finnish primary care centres. Each was asked to enrol 10-12 consecutive patients with type-2 diabetes between March 2011 and August 2012. Along with the office blood pressure measurements and laboratory tests, the presence of albuminuria was measured and glomerular filtration rate estimated (eGFR). The 2013 ESH criteria for diabetic hypertensive patients (<140/85 mmHg) was reached by 39% of all 625 study patients and 38% of the pharmacologically treated 520 patients. The absence of detectable albumin in urine was significantly associated with the control of systolic blood pressure and achievement of treatment goals. Beta blockers were the most common antihypertensive agents and patients treated with them had lower eGFR compared to those not treated with these agents. The blood pressure of patients was not in full concordance with the present guideline recommendations. However, satisfactory improvement in blood pressure control, reduction of albuminuria and hence ESRD prevention was achieved.

  18. A new real time tsunami detection algorithm for bottom pressure measurements in open ocean: characterization and benchmarks

    NASA Astrophysics Data System (ADS)

    Pignagnoli, Luca; Chierici, Francesco; Embriaco, Davide

    2010-05-01

    In the last decades the use of the Bottom Pressure Recorder (BPR) in a deep ocean environment for tsunami detection has had a relevant development. A key role for an early warning system based on BPRs is played by the tsunami detection algorithms running in real time on the BPR itself or on land. We present a new algorithm for tsunami detection based on real time pressure data analysis by a filtering cascade. This procedure consists of a tide removing, spike removing, low pass filtering and linear prediction or band pass filtering; the output filtered data is then matched against a given pressure threshold. Once exceeded a parent tsunami signal is detected. The main characteristics of the algorithm is its site specific adaptability and its flexibility that greatly enhance the detection reliability. In particular it was shown that removing the predicted tide strongly reduces the dynamical range of the pressure time series, allowing the detection of small tsunami signal. The algorithm can also be applied to the data acquired by a tide gauge. The algorithm is particularly designed and optimized to be used in an autonomous early warning system. A statistical method for algorithms evaluation has been developed in order to characterize the algorithms features with particular regards to false alarm probability, detection probability and detection earliness. Different configurations of the algorithm are tested for comparison using both synthetic and real pressure data set recorded in different environmental conditions and locations. The algorithm was installed onboard of the GEOSTAR abyssal station, deployed at 3264 m depth in the Gulf of Cadiz and successfully operated for 1 year, from August 2007 to August 2008.

  19. Effects of heterogeneities on the partitioning of airway and tissue properties in normal mice.

    PubMed

    Ito, Satoru; Lutchen, Kenneth R; Suki, Béla

    2007-03-01

    We measured the mechanical properties of the respiratory system of C57BL/6 mice using the optimal ventilation waveform method in closed- and open-chest conditions at different positive end-expiratory pressures. The tissue damping (G), tissue elastance (H), airway resistance (Raw), and hysteresivity were obtained by fitting the impedance data to three different models: a constant-phase model by Hantos et al. (Hantos Z, Daroczy B, Suki B, Nagy S, Fredberg JJ. J Appl Physiol 72: 168-178, 1992), a heterogeneous Raw model by Suki et al. (Suki B, Yuan H, Zhang Q, Lutchen KR. J Appl Physiol 82: 1349-1359, 1997), and a heterogeneous H model by Ito et al. (Ito S, Ingenito EP, Arold SP, Parameswaran H, Tgavalekos NT, Lutchen KR, Suki B. J Appl Physiol 97: 204-212, 2004). Both in the closed- and open-chest conditions, G and hysteresivity were the lowest and Raw the highest in the heterogeneous Raw model, and G and H were the largest in the heterogeneous H model. Values of G, Raw, and hysteresivity were significantly higher in the closed-chest than in the open-chest condition. However, H was not affected by the conditions. When the tidal volume of the optimal ventilation waveform was decreased from 8 to 4 ml/kg in the closed-chest condition, G and hysteresivity significantly increased, but there were smaller changes in H or Raw. In summary, values of the obtained mechanical properties varied among these models, primarily due to heterogeneity. Moreover, the mechanical parameters were significantly affected by the chest wall and tidal volume in mice. Contribution of the chest wall and heterogeneity to the mechanical properties should be carefully considered in physiological studies in which partitioning of airway and tissue properties are attempted.

  20. A new removable airway stent

    PubMed Central

    Amundsen, Tore; Sørhaug, Sveinung; Leira, Håkon Olav; Tyvold, Stig Sverre; Langø, Thomas; Hammer, Tommy; Manstad-Hulaas, Frode; Mattsson, Erney

    2016-01-01

    Background Malignant airway obstruction is a feared complication and will most probably occur more frequently in the future because of increasing cancer incidence and increased life expectancy in cancer patients. Minimal invasive treatment using airway stents represents a meaningful and life-saving palliation. We present a new removable airway stent for improved individualised treatment. Methods To our knowledge, the new airway stent is the world's first knitted and uncovered self-expanding metal stent, which can unravel and be completely removed. In an in vivo model using two anaesthetised and spontaneously breathing pigs, we deployed and subsequently removed the stents by unravelling the device. The procedures were executed by flexible bronchoscopy in an acute and a chronic setting – a ‘proof-of-principle’ study. Results The new stent was easily and accurately deployed in the central airways, and it remained fixed in its original position. It was easy to unravel and completely remove from the airways without clinically significant complications. During the presence of the stent in the chronic study, granulation tissue was induced. This tissue disappeared spontaneously with the removal. Conclusions The new removable stent functioned according to its purpose and unravelled easily, and it was completely removed without significant technical or medical complications. Induced granulation tissue disappeared spontaneously. Further studies on animals and humans are needed to define its optimal indications and future use. PMID:27608269

  1. Chloride and potassium channels in cystic fibrosis airway epithelia

    NASA Astrophysics Data System (ADS)

    Welsh, Michael J.; Liedtke, Carole M.

    1986-07-01

    Cystic fibrosis, the most common lethal genetic disease in Caucasians, is characterized by a decreased permeability in sweat gland duct and airway epithelia. In sweat duct epithelium, a decreased Cl- permeability accounts for the abnormally increased salt content of sweat1. In airway epithelia a decreased Cl- permeability, and possibly increased sodium absorption, may account for the abnormal respiratory tract fluid2,3. The Cl- impermeability has been localized to the apical membrane of cystic fibrosis airway epithelial cells4. The finding that hormonally regulated Cl- channels make the apical membrane Cl- permeable in normal airway epithelial cells5 suggested abnormal Cl- channel function in cystic fibrosis. Here we report that excised, cell-free patches of membrane from cystic fibrosis epithelial cells contain Cl- channels that have the same conductive properties as Cl- channels from normal cells. However, Cl- channels from cystic fibrosis cells did not open when they were attached to the cell. These findings suggest defective regulation of Cl- channels in cystic fibrosis epithelia; to begin to address this issue, we performed two studies. First, we found that isoprenaline, which stimulates Cl- secretion, increases cellular levels of cyclic AMP in a similar manner in cystic fibrosis and non-cystic fibrosis epithelial cells. Second, we show that adrenergic agonists open calcium-activated potassium channels, indirectly suggesting that calcium-dependent stimulus-response coupling is intact in cystic fibrosis. These data suggest defective regulation of Cl- channels at a site distal to cAMP accumulation.

  2. Optical and RF electrical characteristics of atmospheric pressure open-air hollow slot microplasmas and application to bacterial inactivation

    NASA Astrophysics Data System (ADS)

    Rahul, R.; Stan, O.; Rahman, A.; Littlefield, E.; Hoshimiya, K.; Yalin, A. P.; Sharma, A.; Pruden, A.; Moore, C. A.; Yu, Z.; Collins, G. J.

    2005-06-01

    We report electrical properties of radio frequency (RF)-driven hollow slot microplasmas operating in open air but with uniform luminous discharges at RF current densities of the order of A cm-2. We employ interelectrode separations of 100-600 µm to achieve this open-air operation but because the linear slot dimension of our electrode designs are of extended length, we can achieve, for example, open-air slot shaped plasmas 30 cm in length. This creates a linear plasma source for wide area plasma driven surface treatment applications. RF voltages at frequencies of 4-60 MHz are applied to an interior electrode to both ignite and sustain the plasma between electrodes. The outer slotted electrode is grounded. Illustrative absolute emission of optical spectra from this source is presented in the region from 100 to 400 nm as well as total oxygen radical fluxes from the source. We present both RF breakdown and sustaining voltage measurements as well as impedance values measured for the microplasmas, which use flowing rare gas in the interelectrode region exiting into open air. The requirement for rare gas flow is necessary to get uniform plasmas of dimensions over 30 cm, but is a practical disadvantage. In one mode of operation we create an out-flowing afterglow plasma plume, which extends 1-3 mm from the grounded open slot allowing for treatment of work pieces placed millimetres away from the grounded electrode. This afterglow configuration also allows for lower gas temperatures impinging on substrates, than the use of active plasmas. Work pieces are not required to be part of any electrical circuit, bringing additional practical advantages. We present a crude lumped parameter equivalent circuit model to analyse the effects of changing RF sheaths with frequency of excitation and applied RF current to better understand the relative roles of sheath and bulk plasma behaviour observed in electrical characteristics. Estimates of the bulk plasma densities are also provided

  3. Functional contribution of mandibular advancement to awake upper airway patency in obstructive sleep apnea.

    PubMed

    Tsuiki, Satoru; Ryan, C Frank; Lowe, Alan A; Inoue, Yuichi

    2007-12-01

    In the narrowed upper airway of patients with obstructive sleep apnea (OSA), a neuromuscular compensatory mechanism augments the activity of the upper airway dilator muscles in defense of upper airway patency, particularly during inspiration. We hypothesized that mechanical enlargement of the upper airway by a mandibular advancement oral appliance would permit a reduction in this neuromuscular compensation during wakefulness. To test this hypothesis, we focused on changes in the cross-sectional (CS) area of the upper airway before and after emplacement of a ventrally titrated oral appliance in 12 awake OSA patients. The CS areas at the end of tidal expiration (CS area-EET) and at the nadir of intraluminal pressure during inspiration (CS area-IN) were obtained using videoendoscopy. The median apnea-hypopnea index decreased with mandibular advancement. Before mandibular advancement, there was no difference between CS area-EET and CS area-IN in the velopharynx, oropharynx, and hypopharynx. This indicates that upper airway dilator muscle activity increased during inspiration to counteract the intraluminal negative pressure of the upper airway. After mandibular advancement, CS area-EET increased in the velopharynx, oropharynx, and hypopharynx, but CS area-IN was unchanged at any level and was less than CS area-EET in the velopharynx and oropharynx. These findings suggest that mandibular advancement enlarges the upper airway and may reduce upper airway dilator muscle activity during inspiration. We conclude that oral appliances act to return the upper airway towards a normal configuration and pattern of muscle function in OSA patients.

  4. Linking Turgor with ABA Biosynthesis: Implications for Stomatal Responses to Vapor Pressure Deficit across Land Plants1[OPEN

    PubMed Central

    McAdam, Scott A.M.; Brodribb, Timothy J.

    2016-01-01

    Stomatal responses to changes in vapor pressure deficit (VPD) constitute the predominant form of daytime gas-exchange regulation in plants. Stomatal closure in response to increased VPD is driven by the rapid up-regulation of foliar abscisic acid (ABA) biosynthesis and ABA levels in angiosperms; however, very little is known about the physiological trigger for this increase in ABA biosynthesis at increased VPD. Using a novel method of modifying leaf cell turgor by the application of external pressures, we test whether changes in turgor pressure can trigger increases in foliar ABA levels over 20 min, a period of time most relevant to the stomatal response to VPD. We found in angiosperm species that the biosynthesis of ABA was triggered by reductions in leaf turgor, and in two species tested, that a higher sensitivity of ABA synthesis to leaf turgor corresponded with a higher stomatal sensitivity to VPD. In contrast, representative species from nonflowering plant lineages did not show a rapid turgor-triggered increase in foliar ABA levels, which is consistent with previous studies demonstrating passive stomatal responses to changes in VPD in these lineages. Our method provides a new tool for characterizing the response of stomata to water availability. PMID:27208264

  5. Numerical Simulation for Mechanism of Airway Narrowing in Asthma

    NASA Astrophysics Data System (ADS)

    Bando, Kiyoshi; Yamashita, Daisuke; Ohba, Kenkichi

    A calculation model is proposed to examine the generation mechanism of the numerous lobes on the inner-wall of the airway in asthmatic patients and to clarify luminal occlusion of the airway inducing breathing difficulties. The basement membrane in the airway wall is modeled as a two-dimensional thin-walled shell having inertia force due to the mass, and the smooth muscle contraction effect is replaced by uniform transmural pressure applied to the basement membrane. A dynamic explicit finite element method is used as a numerical simulation method. To examine the validity of the present model, simulation of an asthma attack is performed. The number of lobes generated in the basement membrane increases when transmural pressure is applied in a shorter time period. When the remodeling of the basement membrane occurs characterized by thickening and hardening, it is demonstrated that the number of lobes decreases and the narrowing of the airway lumen becomes severe. Comparison of the results calculated by the present model with those measured for animal experiments of asthma will be possible.

  6. Upper airway obstruction during midazolam sedation: modification by nasal CPAP.

    PubMed

    Nozaki-Taguchi, N; Isono, S; Nishino, T; Numai, T; Taguchi, N

    1995-08-01

    We examined the depressant effect of midazolam on respiration in 21 healthy women undergoing lower abdominal surgery with spinal anaesthesia. Airway gas flow, airway pressure, and the sound of snoring were recorded together with arterial oxygen saturation (SpO2). After spinal anaesthesia was established, subjects were deeply sedated with pentazocine 15 mg followed by incremental doses of midazolam 1 mg i.v. up to 0.1 mg.kg-1. When SpO2 decreased to < 90% or snoring and/or apnoea was observed, continuous positive airway pressure applied through the nose (nasal CPAP) was increased until the respiratory deterioration was reversed. While one patient remained free of respiratory events, the other 20 patients were successfully treated with nasal CPAP restoring normal SpO2 (95.5 +/- 1.7%) without snoring. Stepwise reduction of nasal CPAP determined the minimally effective CPAP to prevent snoring to be 5.1 +/- 2.1 cm H2O. Further reduction of nasal CPAP induced snoring in 15 patients and obstructive apnoea in five patients with the latter accompanied by a severe reduction of SpO2 (87.4 +/- 6.1%). Patients with apnoea were older than those who snored (P < 0.05. We conclude that upper airway obstruction contributes considerably to decreases in SpO2 during midazolam sedation for spinal anaesthesia.

  7. Dynamic Visco-elastic Buckling Analysis for Airway Model

    NASA Astrophysics Data System (ADS)

    Bando, Kiyoshi; Ohba, Kenkichi; Yamanoi, Yuta

    In order to clarify the mechanism by which the lung airway narrows during an asthma attack, dynamic buckling analysis of the wall was conducted. The wall was modeled using a visco-elastic thin-walled circular cylinder of the Voigt model for the planestress state. A governing equation for dynamic buckling was derived, and in the equation, the contraction of smooth muscle was replaced by uniform inward transmural pressure. The non-dimensional parameters for the buckling wave number n were nondimensional retardation time τ, non-dimensional increasing velocity of inward transmural pressure β, thickness radius ratio α2, radius length ratio η, density ratio ζ, and Poisson's ratio ν. The validity of the theoretical model was confirmed by comparing the calculated wave number with that obtained from the experiment, in which a silicone rubber tube blended with silicone potting gel was used as the in vitro airway model. In addition, the wave number n increased with β. It was necessary to consider the damping effect of the tube model or the airway wall, and n increased by 1.5 to 2 due to the additional mass effect of surrounding tissues of the basement membrane in the airway wall.

  8. On locating the obstruction in the human upper airway

    NASA Astrophysics Data System (ADS)

    Wang, Yong; Elghobashi, S.

    2013-11-01

    The fluid dynamical properties of the air flow in the human upper airway (UA) are not fully understood at present due to the three-dimensional, patient-specific complex geometry of the airway, flow transition from laminar to turbulent and flow-structure interaction during the breathing cycle. One of the major challenges to surgeons is determining the location of the UA obstruction before performing corrective surgeries. It is quite difficult at present to experimentally measure the instantaneous velocity and pressure at specific points in the human airway. On the other hand, direct numerical simulation (DNS) can predict all the flow properties and resolve all its relevant length- and time-scales. We developed a DNS solver with lattice Boltzmann method (LBM), and used it to investigate the flow in two patient-specific UAs reconstructed from CT scan data. Inspiration and expiration flows through these two airways are studied and compared. Pressure gradient-time signals at different locations in the UAs are used to determine the location of the obstruction. This work was supported by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH).

  9. Human airway ciliary dynamics

    PubMed Central

    Thompson, Kristin; Knowles, Michael R.; Davis, C. William

    2013-01-01

    Airway cilia depend on precise changes in shape to transport the mucus gel overlying mucosal surfaces. The ciliary motion can be recorded in several planes using video microscopy. However, cilia are densely packed, and automated computerized systems are not available to convert these ciliary shape changes into forms that are useful for testing theoretical models of ciliary function. We developed a system for converting planar ciliary motions recorded by video microscopy into an empirical quantitative model, which is easy to use in validating mathematical models, or in examining ciliary function, e.g., in primary ciliary dyskinesia (PCD). The system we developed allows the manipulation of a model cilium superimposed over a video of beating cilia. Data were analyzed to determine shear angles and velocity vectors of points along the cilium. Extracted waveforms were used to construct a composite waveform, which could be used as a standard. Variability was measured as the mean difference in position of points on individual waveforms and the standard. The shapes analyzed were the end-recovery, end-effective, and fastest moving effective and recovery with mean (± SE) differences of 0.31(0.04), 0.25(0.06), 0.50(0.12), 0.50(0.10), μm, respectively. In contrast, the same measures for three different PCD waveforms had values far outside this range. PMID:23144323

  10. Airway Hydration and COPD

    PubMed Central

    Ghosh, Arunava; Boucher, R.C.; Tarran, Robert

    2015-01-01

    Chronic obstructive pulmonary disease (COPD) is one of the prevalent causes of worldwide mortality and encompasses two major clinical phenotypes, i.e., chronic bronchitis (CB) and emphysema. The most common cause of COPD is chronic tobacco inhalation. Research focused on the chronic bronchitic phenotype of COPD has identified several pathological processes that drive disease initiation and progression. For example, the lung’s mucociliary clearance (MCC) system performs the critical task of clearing inhaled pathogens and toxic materials from the lung. MCC efficiency is dependent on: (i) the ability of apical plasma membrane ion channels such as the cystic fibrosis transmembrane conductance regulator (CFTR) and the epithelial Na+ channel (ENaC) to maintain airway hydration; (ii) ciliary beating; and, (iii) appropriate rates of mucin secretion. Each of these components is impaired in CB and likely contributes to the mucus stasis/accumulation seen in CB patients. This review highlights the cellular components responsible for maintaining MCC and how this process is disrupted following tobacco exposure and with CB. We shall also discuss existing therapeutic strategies for the treatment of chronic bronchitis and how components of the MCC can be used as biomarkers for the evaluation of tobacco or tobacco-like-product exposure. PMID:26068443

  11. Oxygenation, Ventilation, and Airway Management in Out-of-Hospital Cardiac Arrest: A Review

    PubMed Central

    Henlin, Tomas; Michalek, Pavel; Tyll, Tomas; Hinds, John D.; Dobias, Milos

    2014-01-01

    Recently published evidence has challenged some protocols related to oxygenation, ventilation, and airway management for out-of-hospital cardiac arrest. Interrupting chest compressions to attempt airway intervention in the early stages of OHCA in adults may worsen patient outcomes. The change of BLS algorithms from ABC to CAB was recommended by the AHA in 2010. Passive insufflation of oxygen into a patent airway may provide oxygenation in the early stages of cardiac arrest. Various alternatives to tracheal intubation or bag-mask ventilation have been trialled for prehospital airway management. Simple methods of airway management are associated with similar outcomes as tracheal intubation in patients with OHCA. The insertion of a laryngeal mask airway is probably associated with worse neurologically intact survival rates in comparison with other methods of airway management. Hyperoxemia following OHCA may have a deleterious effect on the neurological recovery of patients. Extracorporeal oxygenation techniques have been utilized by specialized centers, though their use in OHCA remains controversial. Chest hyperinflation and positive airway pressure may have a negative impact on hemodynamics during resuscitation and should be avoided. Dyscarbia in the postresuscitation period is relatively common, mainly in association with therapeutic hypothermia, and may worsen neurological outcome. PMID:24724081

  12. Kinematic MRI study of upper-airway biomechanics using electrical muscle stimulation

    NASA Astrophysics Data System (ADS)

    Brennick, Michael J.; Margulies, Susan S.; Ford, John C.; Gefter, Warren B.; Pack, Allan I.

    1997-05-01

    We have developed a new and powerful method to study the movement and function of upper airway muscles. Our method is to use direct electrical stimulation of individual upper airway muscles, while performing state of the art high resolution magnetic resonance imaging (MRI). We have adapted a paralyzed isolated UA cat model so that positive or negative static pressure in the UA can be controlled at specific levels while electrical muscle stimulation is applied during MRI. With these techniques we can assess the effect of muscle stimulation on airway cross-sectional area compliance and soft tissue motion. We are reporting the preliminary results and MRI techniques which have enabled us to examine changes in airway dimensions which result form electrical stimulation of specific upper airway dilator muscles. The results of this study will be relevant to the development of new clinical treatments for obstructive sleep apnea by providing new information as to exactly how upper airway muscles function to dilate the upper airway and the strength of stimulation required to prevent the airway obstruction when overall muscle tone may not be sufficient to maintain regular breathing.

  13. Altering the mechanical scenario to decrease the driving pressure.

    PubMed

    Borges, João Batista; Hedenstierna, Göran; Larsson, Anders; Suarez-Sipmann, Fernando

    2015-09-21

    Ventilator settings resulting in decreased driving pressure (ΔP) are positively associated with survival. How to further foster the potential beneficial mediator effect of a reduced ΔP? One possibility is promoting the active modification of the lung's "mechanical scenario" by means of lung recruitment and positive end-expiratory pressure selection. By taking into account the individual distribution of the threshold-opening airway pressures to achieve maximal recruitment, a redistribution of the tidal volume from overdistended to newly recruited lung occurs. The resulting more homogeneous distribution of transpulmonary pressures may induce a relief of overdistension in the upper regions. The gain in lung compliance after a successful recruitment rescales the size of the functional lung, potentially allowing for a further reduction in ΔP.

  14. Effects of hypercapnia and inspiratory flow-resistive loading on respiratory activity in chronic airways obstruction.

    PubMed Central

    Altose, M D; McCauley, W C; Kelsen, S G; Cherniack, N S

    1977-01-01

    The respiratory responses to hypercapnia alone and to hypercapnia and flow-resistive loading during inspiration were studied in normal individuals and in eucapnic and hypercapnic patients with chronic airways obstruction. Responses were assessed in terms of minute ventilation and occlusion pressure (mouth pressure during airway occlusion 100 ms after the onset of inspiration). Ventilatory responses to CO2 (deltaV/deltaPCO2) were distinctly subnormal in both groups of patients with airways obstruction. The two groups of patients, however, showed different occlusion pressure responses to CO2 (deltaP100/deltaPCO2): deltaP100/deltaPCO2 was normal in the eucapnic patients but subnormal in the hypercapnic patients. Flow-resistive loading during inspiration reduced deltaV/deltaPCO2 both in normal subjects and in patients with airways obstruction. The occlusion pressure response to CO2 increased in normal subjects during flow-resistive loading but remained unchanged in both groups of patients with chronic airways obstruction. These results indicate that while chemosensitivity as determined by deltaP100/deltaPCO2 is impaired only in hypercapnic patients with chronic airways obstruction, an acute increase in flow resistance elicits a subnormal increase in respiratory efferent activity in both eucapnic and hypercapnic patients. PMID:838862

  15. Preparation and kinetic performance assessment of thick film 10-20 μm open tubular silica capillaries in normal phase high pressure liquid chromatography.

    PubMed

    Forster, Simon; Kolmar, Harald; Altmaier, Stephan

    2013-11-08

    It is well-known that the open tubular column design basically can offer very high plate numbers. Experimental realization has however not kept pace with theoretical considerations, lacking efficient methods for the deposition of a thick film porous layer within a microbore capillary. A previously published sol-gel synthesis method was extended from 20 μm to 10 μm inner diameter fused silica capillaries and the resulting columns were compared to a monolithic reference capillary in terms of kinetic performance at pressure maximum. Column permeability was investigated and pressure/flow-diagrams were obtained with a 400-fold permeability gain for the open tubes. Structural characterizations regarding layer thickness and surface porosity were carried out and displayed via scanning electron microscopy and nitrogen sorption analysis. Chromatographic results in normal phase mode at elevated mobile phase flow rate reveal the intrinsic performance potential of this column format when it comes to kinetic performance limitation plots, which were constructed for all columns prepared and compared to the monolithic silica reference capillary.

  16. Efficacy of Surgical Airway Plasty for Benign Airway Stenosis

    PubMed Central

    Takahama, Makoto; Nakajima, Ryu; Kimura, Michitaka; Inoue, Hidetoshi; Yamamoto, Ryoji

    2015-01-01

    Background: Long-term patency is required during treatment for benign airway stenosis. This study investigated the effectiveness of surgical airway plasty for benign airway stenosis. Methods: Clinical courses of 20 patients, who were treated with surgical plasty for their benign airway stenosis, were retrospectively investigated. Results: Causes of stenosis were tracheobronchial tuberculosis in 12 patients, post-intubation stenosis in five patients, malacia in two patients, and others in one patient. 28 interventional pulmonology procedures and 20 surgical plasty were performed. Five patients with post-intubation stenosis and four patients with tuberculous stenosis were treated with tracheoplasty. Eight patients with tuberculous stenosis were treated with bronchoplasty, and two patients with malacia were treated with stabilization of the membranous portion. Anastomotic stenosis was observed in four patients, and one to four additional treatments were required. Performance status, Hugh–Jones classification, and ventilatory functions were improved after surgical plasty. Outcomes were fair in patients with tuberculous stenosis and malacia. However, efficacy of surgical plasty for post-intubation stenosis was not observed. Conclusion: Surgical airway plasty may be an acceptable treatment for tuberculous stenosis. Patients with malacia recover well after surgical plasty. There may be untreated patients with malacia who have the potential to benefit from surgical plasty. PMID:26567879

  17. Comparison of streamlined liner of the pharynx airway (SLIPA ™) and laryngeal mask airway: a systematic review and meta-analysis.

    PubMed

    Choi, G J; Kang, H; Baek, C W; Jung, Y H; Woo, Y C; Kim, S H; Kim, J G

    2015-05-01

    We performed a systematic review to compare the efficacy and safety of the streamlined liner of the pharynx airway and laryngeal mask airway used in adults during general anaesthesia. We included 14 studies with studies with 1273 patients in total. There was no evidence of a difference between the two devices in insertion success rate on the first attempt (13 studies, 1143 patients), insertion time (seven studies, 576 patients), ease of insertion (five studies, 466 patients), oropharyngeal leak pressure (eight studies, 771 patients) and the quality of the fibreoptic view of the larynx through the device (three studies, 281 patients). The relative risk (95% CI) of bloodstaining of the device (nine studies, 859 patients) was 2.09 (1.46-3.00) for the streamlined liner of the pharynx airway compared with the laryngeal mask airway. Other adverse events were comparable. Subgroup analysis suggested that the insertion by novice users might be faster and more successful with the streamlined liner of the pharynx airway than the laryngeal mask airway; however, this was from only two studies and 186 patients. The method of size selection of the streamlined liner of the pharynx airway device might also affect the speed of insertion: choosing according to the width of the patient's thyroid cartilage, rather than height, may produce better results.

  18. Regional alveolar pressure during periodic flow. Dual manifestations of gas inertia.

    PubMed Central

    Allen, J L; Frantz, I D; Fredberg, J J

    1985-01-01

    We measured pressure excursions at the airway opening and at the alveoli (PA) as well as measured the regional distribution of PA during forced oscillations of six excised dog lungs while frequency (f[2-32 Hz]), tidal volume (VT [5-80 ml]), and mean transpulmonary pressure (PL [25, 10, and 6 cm H2O]) were varied. PA's were measured in four alveolar capsules glued to the pleura of different lobes. The apex-to-base ratio of PA's was used as an index of the distribution of dynamic lung distension. At low f, there was slight preferential distension of the lung base which was independent of VT, but at higher f, preferential distension of the lung apex was found when VT's were small, whereas preferential distension of the lung base was found when VT's approached or exceeded dead space. These VT-related changes in distribution at high frequencies seem to depend upon the branching geometry of the central airways and the relative importance of convective momentum flux vs. unsteady inertia of gas residing therein, which, in this study, we showed to be proportional to the ratio VT/VD*, where VD* is an index of dead space. Furthermore, they imply substantial alteration in the distribution of ventilation during high frequency ventilation as f, VT, and PL vary. The data also indicate that alveolar and airway opening pressure costs per unit flow delivered at the airway opening exhibit weakly nonlinear behavior and that resonant amplification of PA's, which has been described previously for the case of very small VT's, persists but is damped as VT's approach dead space values. PMID:4031066

  19. Changes in endotracheal tube cuff pressure during laparoscopic surgery in head-up or head-down position

    PubMed Central

    2014-01-01

    Background The abdominal insufflation and surgical positioning in the laparoscopic surgery have been reported to result in an increase of airway pressure. However, associated effects on changes of endotracheal tube cuff pressure are not well established. Methods 70 patients undergoing elective laparoscopic colorectal tumor resection (head-down position, n = 38) and laparoscopic cholecystecomy (head-up position, n = 32) were enrolled and were compared to 15 patients undergoing elective open abdominal surgery. Changes of cuff and airway pressures before and after abdominal insufflation in supine position and after head-down or head-up positioning were analysed and compared. Results There was no significant cuff and airway pressure changes during the first fifteen minutes in open abdominal surgery. After insufflation, the cuff pressure increased from 26 ± 3 to 32 ± 6 and 27 ± 3 to 33 ± 5 cmH2O in patients receiving laparoscopic cholecystecomy and laparoscopic colorectal tumor resection respectively (both p < 0.001). The head-down tilt further increased cuff pressure from 33 ± 5 to 35 ± 5 cmH2O (p < 0.001). There six patients undergoing colorectal tumor resection (18.8%) and eight patients undergoing cholecystecomy (21.1%) had a total increase of cuff pressure more than 10 cm H2O (18.8%). There was no significant correlation between increase of cuff pressure and either the patient's body mass index or the common range of intra-abdominal pressure (10-15 mmHg) used in laparoscopic surgery. Conclusions An increase of endotracheal tube cuff pressure may occur during laparoscopic surgery especially in the head-down position. PMID:25210501

  20. The Airway Microbiome at Birth

    PubMed Central

    Lal, Charitharth Vivek; Travers, Colm; Aghai, Zubair H.; Eipers, Peter; Jilling, Tamas; Halloran, Brian; Carlo, Waldemar A.; Keeley, Jordan; Rezonzew, Gabriel; Kumar, Ranjit; Morrow, Casey; Bhandari, Vineet; Ambalavanan, Namasivayam

    2016-01-01

    Alterations of pulmonary microbiome have been recognized in multiple respiratory disorders. It is critically important to ascertain if an airway microbiome exists at birth and if so, whether it is associated with subsequent lung disease. We found an established diverse and similar airway microbiome at birth in both preterm and term infants, which was more diverse and different from that of older preterm infants with established chronic lung disease (bronchopulmonary dysplasia). Consistent temporal dysbiotic changes in the airway microbiome were seen from birth to the development of bronchopulmonary dysplasia in extremely preterm infants. Genus Lactobacillus was decreased at birth in infants with chorioamnionitis and in preterm infants who subsequently went on to develop lung disease. Our results, taken together with previous literature indicating a placental and amniotic fluid microbiome, suggest fetal acquisition of an airway microbiome. We speculate that the early airway microbiome may prime the developing pulmonary immune system, and dysbiosis in its development may set the stage for subsequent lung disease. PMID:27488092

  1. The role of an ambient pressure oxygen source during one-lung ventilation for thoracoscopic surgery.

    PubMed

    Pfitzner, J

    2016-01-01

    Video-assisted thoracoscopic surgery is facilitated by prompt collapse of the non-ventilated ('operated') lung, and interrupted and impeded if there is a need for oxygen (O2) delivery by continuous positive airways pressure in order to manage hypoxaemia. It has been proposed that connecting an ambient pressure O2 source to the airway of the non-ventilated lung at the time one-lung ventilation is initiated and before the chest is opened will, by avoiding entrainment of ambient nitrogen, serve to facilitate lung collapse. It has also been proposed that leaving the O2 source connected will enable, not only ongoing apnoeic oxygenation before the chest is opened, but also the thoracoscopic procedure to commence with the operated lung fully pre-oxygenated (with an inspired oxygen fraction of 1), and apnoeic oxygenation to continue throughout the operative procedure in those patients who exhibit a degree of small airways patency at ambient pressure. In reality, several factors can influence the speed of collapse of the operated lung, and very many factors can influence the incidence of hypoxaemia during one-lung ventilation. It therefore appears unlikely that the necessary evidence to support these proposals will be forthcoming from randomised clinical studies on large numbers of patients. Rather, the necessary evidence may only be provided by specifically designed within-patient clinical measurement studies. Nevertheless, it is argued that, in the meantime, there is already sufficient rationale for an ambient pressure O2 source to be connected to the airway of the non-ventilated lung, and for it to remain connected for the duration of one-lung ventilation.

  2. Miniaturised medium pressure capillary liquid chromatography system with flexible open platform design using off-the-shelf microfluidic components.

    PubMed

    Li, Yan; Dvořák, Miloš; Nesterenko, Pavel N; Stanley, Roger; Nuchtavorn, Nantana; Krčmová, Lenka Kujovská; Aufartová, Jana; Macka, Mirek

    2015-10-08

    Trends towards portable analytical instrumentation of the last decades have not been equally reflected in developments of portable liquid chromatography (LC) instrumentation for rapid on-site measurements. A miniaturised medium pressure capillary LC (MPLC) system with gradient elution capability has been designed based on a flexible modular microfluidic system using primarily off-the-shelf low cost components to ensure wide accessibility to other analysts. The microfluidic platform was assembled on a breadboard and contained microsyringe pumps and switch valves, complemented with an injection valve and on-capillary detectors, all controlled by a PC. Four miniaturised microsyringe pumps, with 5, 20 and 100 μL syringe volume options, formed the basis of the pumping system. Two pairs of pumps were used for each mobile phase to create gradient elution capability. The two microsyringe pumps in each pairs were linked by two electrically operated microfluidic switching valves and both pairs of pumps were connected through a zero void volume cross-connector, thus providing a low hold-up volume for gradient formation. Sample was injected by a 20 nL nano-LC sampling valve, directly connected to a 18 cm long 100 μm i.d. Chromolith CapRod RP-18 monolithic capillary column. On-capillary LED-based UV-vis photometric detection was conducted through a piece of equal diameter fused silica capillary connected after the column. The performance of the portable LC system was evaluated theoretically and experimentally, including the maximum operating pressure, gradient mixing performance, and the performance of the detectors. The 5 μL microsyringe pump offered the best performance, with typical maximum operating pressures up to 11.4 ± 0.4 MPa (water) and gradient pumping repeatability of between 4 and 9% for gradients between 0.10% s(-1) and 0.33% s(-1). Test analytes of charged and uncharged dyes and pharmaceuticals of varying hydrophobicity showed typical RSD values of 0

  3. Numerical simulation of soft palate movement and airflow in human upper airway by fluid-structure interaction method

    NASA Astrophysics Data System (ADS)

    Sun, Xiuzhen; Yu, Chi; Wang, Yuefang; Liu, Yingxi

    2007-08-01

    In this paper, the authors present airflow field characteristics of human upper airway and soft palate movement attitude during breathing. On the basis of the data taken from the spiral computerized tomography images of a healthy person and a patient with Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS), three-dimensional models of upper airway cavity and soft palate are reconstructed by the method of surface rendering. Numerical simulation is performed for airflow in the upper airway and displacement of soft palate by fluid-structure interaction analysis. The reconstructed three-dimensional models precisely preserve the original configuration of upper airways and soft palate. The results of the pressure and velocity distributions in the airflow field are quantitatively determined, and the displacement of soft palate is presented. Pressure gradients of airway are lower for the healthy person and the airflow distribution is quite uniform in the case of free breathing. However, the OSAHS patient remarkably escalates both the pressure and velocity in the upper airway, and causes higher displacement of the soft palate. The present study is useful in revealing pathogenesis and quantitative mutual relationship between configuration and function of the upper airway as well as in diagnosing diseases related to anatomical structure and function of the upper airway.

  4. Negative pressure pulmonary edema after nasal fracture reduction in an obese female patient: a case report

    PubMed Central

    Choi, Eunkyung; Yi, Junggu; Jeon, Younghoon

    2015-01-01

    Postoperative negative pressure pulmonary edema (NPPE) is a rare, but well-known life-threatening complication of acute upper airway obstruction (UAO) which develops after general anesthesia. The pronounced inspiratory efforts following UAO lead to excessive negative inspiratory pressure, which may cause acute pulmonary edema. Early recognition and prompt treatment of NPPE is necessary to prevent patient morbidity and mortality. In addition, the physician should carefully manage the patient who has risk factors of UAO to prevent this situation. We experienced a case of NPPE following laryngospasm after tracheal extubation in an obese patient who underwent open reduction of orbital wall and nasal bone surgery. PMID:26316826

  5. Cystic Fibrosis Transmembrane Conductance Regulator in Sarcoplasmic Reticulum of Airway Smooth Muscle. Implications for Airway Contractility

    PubMed Central

    Cook, Daniel P.; Rector, Michael V.; Bouzek, Drake C.; Michalski, Andrew S.; Gansemer, Nicholas D.; Reznikov, Leah R.; Li, Xiaopeng; Stroik, Mallory R.; Ostedgaard, Lynda S.; Abou Alaiwa, Mahmoud H.; Thompson, Michael A.; Prakash, Y. S.; Krishnan, Ramaswamy; Meyerholz, David K.; Seow, Chun Y.

    2016-01-01

    Rationale: An asthma-like airway phenotype has been described in people with cystic fibrosis (CF). Whether these findings are directly caused by loss of CF transmembrane conductance regulator (CFTR) function or secondary to chronic airway infection and/or inflammation has been difficult to determine. Objectives: Airway contractility is primarily determined by airway smooth muscle. We tested the hypothesis that CFTR is expressed in airway smooth muscle and directly affects airway smooth muscle contractility. Methods: Newborn pigs, both wild type and with CF (before the onset of airway infection and inflammation), were used in this study. High-resolution immunofluorescence was used to identify the subcellular localization of CFTR in airway smooth muscle. Airway smooth muscle function was determined with tissue myography, intracellular calcium measurements, and regulatory myosin light chain phosphorylation status. Precision-cut lung slices were used to investigate the therapeutic potential of CFTR modulation on airway reactivity. Measurements and Main Results: We found that CFTR localizes to the sarcoplasmic reticulum compartment of airway smooth muscle and regulates airway smooth muscle tone. Loss of CFTR function led to delayed calcium reuptake following cholinergic stimulation and increased myosin light chain phosphorylation. CFTR potentiation with ivacaftor decreased airway reactivity in precision-cut lung slices following cholinergic stimulation. Conclusions: Loss of CFTR alters porcine airway smooth muscle function and may contribute to the airflow obstruction phenotype observed in human CF. Airway smooth muscle CFTR may represent a therapeutic target in CF and other diseases of airway narrowing. PMID:26488271

  6. [Orthodontics and the upper airway].

    PubMed

    Cobo Plana, J; de Carlos Villafranca, F; Macías Escalada, E

    2004-03-01

    One of the general aims of orthodontic treatment and of the combination of orthodontics and orthognathic surgery is to achieve good occlusion and aesthetic improvement, especially in cases of severe dentoskeletal deformities. However, on many occasions, the parameters of the upper airways are not taken into account when the aims of conventional treatment are fulfilled. Patients with obstructive alterations during sleep represent for the orthodontist a type of patient who differs from the normal; for them, treatment should include the objective of improving oxygen saturation. Here, functional considerations should outweigh purely aesthetic ones. It is important, when making an orthodontic, surgical or combined diagnosis for a patient, to bear in mind the impact that treatment may have on the upper airways. Good aesthetics should never be achieved for some of our patients at the expense of diminishing the capacity of their upper airways.

  7. Selection pressure on the hepatitis B virus pre-S/S and P open reading frames in Tongan subjects with a chronic hepatitis B virus infection.

    PubMed

    Abbott, William G H; Tsai, Peter; Ross, Howard A; 'Ofanoa, Malakai; Trevarton, Alexander J; Hornell, John; Munn, Stephen R; Gane, Edward J

    2012-11-01

    Identification of the full repertoire of hepatitis B virus (HBV) peptides that are presented to CD8+ T cells by common HLA class I alleles will be useful for designing immunotherapies for chronic hepatitis B. One hundred and seventy five cloned sequences containing the pre-S/S and P open reading frames (ORF) of the HBV were obtained from serum HBV-DNA of HBeAg-positive (n=4) and HBeAg-negative (inactive healthy carriers (IHC), n=16) Tongan subjects with an inactive chronic HBV infection. In addition, 34 and 32 sequences were obtained 5.2±1.4 (mean±SD) years apart from eight subjects. PAML was used to identify codons in the pre-S/S and P ORFs that were under positive selection pressure (ω>1). The number of non-synonymous substitutions in these codons was compared in IHC who were homozygous for either HLA-B∗4001 (n=9) or HLA-B*5602 (n=7), and who were either positive (n=6) or negative (n=10) for HLA-A*02. 34 codons in the pre-S/S and 11 codons in the P ORFs were under positive selection pressure. There was a higher number of non-synonymous substitutions in these codons in HBeAg-negative versus HBeAg-positive subjects in the P (p=0.02) but not the pre-S/S (p=0.64) ORF. There was no association between any HLA class I allele and non-synonymous substitutions in these codons. There was no increase in positive selection pressure on the pre-S/S and P ORFs with time. In conclusion, we could not find HLA class I-restricted selection pressure on any pre-S/S or P ORF amino acid; raising the possibility that peptide-based immunotherapies for chronic hepatitis B may not require peptides from these ORFs.

  8. Airway surface liquid volume expansion induces rapid changes in amiloride-sensitive Na+ transport across upper airway epithelium-Implications concerning the resolution of pulmonary edema

    PubMed Central

    Azizi, Fouad; Arredouani, Abdelilah; Mohammad, Ramzi M

    2015-01-01

    During airway inflammation, airway surface liquid volume (ASLV) expansion may result from the movement of plasma proteins and excess liquid into the airway lumen due to extravasation and elevation of subepithelial hydrostatic pressure. We previously demonstrated that elevation of submucosal hydrostatic pressure increases airway epithelium permeability resulting in ASLV expansion by 500 μL cm−2 h−1. Liquid reabsorption by healthy airway epithelium is regulated by active Na+ transport at a rate of 5 μL cm−2 h−1. Thus, during inflammation the airway epithelium may be submerged by a large volume of luminal liquid. Here, we have investigated the mechanism by which ASLV expansion alters active epithelial Na+ transport, and we have characterized the time course of the change. We used primary cultures of tracheal airway epithelium maintained under air interface (basal ASLV, depth is 7 ± 0.5 μm). To mimic airway flooding, ASLV was expanded to a depth of 5 mm. On switching from basal to expanded ASLV conditions, short-circuit current (Isc, a measure of total transepithelial active ion transport) declined by 90% with a half-time (t1/2) of 1 h. 24 h after the switch, there was no significant change in ATP concentration nor in the number of functional sodium pumps as revealed by [3H]-ouabain binding. However, amiloride-sensitive uptake of 22Na+ was reduced by 70% upon ASLV expansion. This process is reversible since after returning cells back to air interface, Isc recovered with a t1/2 of 5–10 h. These results may have important clinical implications concerning the development of Na+ channels activators and resolution of pulmonary edema. PMID:26333829

  9. An Anesthesiologist's Perspective on the History of Basic Airway Management: The "Preanesthetic" Era-1700 to 1846.

    PubMed

    Matioc, Adrian A

    2016-02-01

    Basic airway management modern history starts in the early 18th century in the context of resuscitation of the apparently dead. History saw the rise and fall of the mouth-to-mouth and then of the instrumental positive-pressure ventilation generated by bellows. Pulmonary ventilation had a secondary role to external and internal organ stimulation in resuscitation of the apparently dead. Airway access for the extraglottic technique was to the victim's nose. The bellows-to-nose technique was the "basic airway management technique" applicable by both medical and nonmedical personnel. Although the techniques had been described at the time, very few physicians practiced glottic (intubation) and subglottic (tracheotomy) techniques. Before the anesthetic era, positive-pressure ventilation was discredited and replaced by manual negative-pressure techniques. In the middle of the 19th century, physicians who would soon administer anesthetic gases were unfamiliar with the positive-pressure ventilation concept.

  10. Airway Reflux, Cough and Respiratory Disease

    PubMed Central

    Molyneux, Ian D.; Morice, Alyn H.

    2011-01-01

    It is increasingly accepted that the effects of gastro-oesophageal reflux are not limited to the gastrointestinal tract. The adjacent respiratory structures are also at risk from material ejected from the proximal oesophagus as a result of the failure of anatomical and physiological barriers. There is evidence of the influence of reflux on several respiratory and otorhinological conditions and although in many cases the precise mechanism has yet to be elucidated, the association alone opens potential novel avenues of therapy to clinicians struggling to treat patients with apparently intractable respiratory complaints. This review provides a description of the airway reflux syndrome, its effects on the lung and current and future therapeutic options. PMID:23251752

  11. Comparative Efficacy of the Air-Q Intubating Laryngeal Airway during General Anesthesia in Pediatric Patients: A Systematic Review and Meta-Analysis

    PubMed Central

    Ahn, Eun Jin; Choi, Geun Joo; Kang, Hyun; Baek, Chong Wha; Jung, Yong Hun; Woo, Young Cheol; Bang, Si Ra

    2016-01-01

    Air-Q® (air-Q) is a supraglottic airway device which can be used as a guidance of intubation in pediatric as well as in adult patients. We evaluated the efficacy and safety of air-Q compared to other airway devices during general anesthesia in pediatric patients by conducting a systematic review and meta-analysis. A total of 10 studies including 789 patients were included in the final analysis. Compared with other supraglottic airway devices, air-Q showed no evidence for a difference in leakage pressure and insertion time. The ease of insertion was significantly lower than other supraglottic airway devices. The success rate of intubation was significantly lower than other airway devices. However, fiberoptic view was better through the air-Q than other supraglottic airway devices. Therefore, air-Q could be a safe substitute for other airway devices and may provide better fiberoptic bronchoscopic view. PMID:27419134

  12. Airway Assessment for Office Sedation/Anesthesia.

    PubMed

    Rosenberg, Morton B; Phero, James C

    2015-01-01

    Whenever a patient is about to receive sedation or general anesthesia, no matter what the technique, the preoperative assessment of the airway is one of the most important steps in ensuring patient safety and positive outcomes. This article, Part III in the series on airway management, is directed at the ambulatory office practice and focuses on predicting the success of advanced airway rescue techniques.

  13. Open circuit mouthpiece ventilation: Concise clinical review.

    PubMed

    Garuti, G; Nicolini, A; Grecchi, B; Lusuardi, M; Winck, J C; Bach, J R

    2014-01-01

    In 2013 new "mouthpiece ventilation" modes are being introduced to commercially available portable ventilators. Despite this, there is little knowledge of how to use noninvasive intermittent positive pressure ventilation (NIV) as opposed to bi-level positive airway pressure (PAP) and both have almost exclusively been reported to have been used via nasal or oro-nasal interfaces rather than via a simple mouthpiece. Non-invasive ventilation is often reported as failing because of airway secretion encumbrance, because of hypercapnia due to inadequate bi-level PAP settings, or poor interface tolerance. The latter can be caused by factors such as excessive pressure on the face from poor fit, excessive oral air leak, anxiety, claustrophobia, and patient-ventilator dys-synchrony. Thus, the interface plays a crucial role in tolerance and effectiveness. Interfaces that cover the nose and/or nose and mouth (oro-nasal) are the most commonly used but are more likely to cause skin breakdown and claustrophobia. Most associated drawbacks can be avoided by using mouthpiece NIV. Open-circuit mouthpiece NIV is being used by large populations in some centers for daytime ventilatory support and complements nocturnal NIV via "mask" interfaces for nocturnal ventilatory support. Mouthpiece NIV is also being used for sleep with the mouthpiece fixed in place by a lip-covering flange. Small 15 and 22mm angled mouthpieces and straw-type mouthpieces are the most commonly used. NIV via mouthpiece is being used as an effective alternative to ventilatory support via tracheostomy tube (TMV) and is associated with a reduced risk of pneumonias and other respiratory complications. Its use facilitates "air-stacking" to improve cough, speech, and pulmonary compliance, all of which better maintain quality of life for patients with neuromuscular diseases (NMDs) than the invasive alternatives. Considering these benefits and the new availability of mouthpiece ventilator modes, wider knowledge of this

  14. Comments to Role of upper airway ultrasound in airway management.

    PubMed

    Lien, Wan-Ching

    2017-01-01

    Tracheal ultrasound can be an alternative diagnostic tool in airway management, besides traditional confirmatory methods such as capnography and auscultation. The standard image is a hyperechoic air-mucosa (A-M) interface with a reverberation artifact posteriorly (comet-tail artifact). If the second A-M interface appears, which we call a "double-tract sign," esophageal intubation is considered.

  15. Molecular mechanisms controlling CFTR gene expression in the airway

    PubMed Central

    Zhang, Zhaolin; Ott, Christopher J; Lewandowska, Marzena A; Leir, Shih-Hsing; Harris, Ann

    2012-01-01

    Abstract The low levels of CFTR gene expression and paucity of CFTR protein in human airway epithelial cells are not easily reconciled with the pivotal role of the lung in cystic fibrosis pathology. Previous data suggested that the regulatory mechanisms controlling CFTR gene expression might be different in airway epithelium in comparison to intestinal epithelium where CFTR mRNA and protein is much more abundant. Here we examine chromatin structure and modification across the CFTR locus in primary human tracheal (HTE) and bronchial (NHBE) epithelial cells and airway cell lines including 16HBE14o- and Calu3. We identify regions of open chromatin that appear selective for primary airway epithelial cells and show that several of these are enriched for a histone modification (H3K4me1) that is characteristic of enhancers. Consistent with these observations, three of these sites encompass elements that have cooperative enhancer function in reporter gene assays in 16HBE14o- cells. Finally, we use chromosome conformation capture (3C) to examine the three-dimensional structure of nearly 800 kb of chromosome 7 encompassing CFTR and observe long-range interactions between the CFTR promoter and regions far outside the locus in cell types that express high levels of CFTR. PMID:21895967

  16. Uniform, stable, and efficient planar-heterojunction perovskite solar cells by facile low-pressure chemical vapor deposition under fully open-air conditions.

    PubMed

    Luo, Paifeng; Liu, Zhaofan; Xia, Wei; Yuan, Chenchen; Cheng, Jigui; Lu, Yingwei

    2015-02-04

    Recently, hybrid perovskite solar cells (PSCs) have attracted extensive attention due to their high efficiency and simple preparing process. Herein, a facile low-pressure chemical vapor deposition (LPCVD) technology is first developed to fabricate PSCs, which can effectively reduce the over-rapid intercalating reaction rate and easily overcome this blocking issue during the solution process. As a result, the prepared uniform perovskite films exhibit good crystallization, strong absorption, and long carrier diffusion length. More strikingly, CH3NH3PbI3 absorbers by LPCVD demonstrate excellent moisture-resistant feature even under laser illumination and high-temperature conditions, which indicates that our proprietary method is very suitable for the future low-cost, nonvacuum production of the new generation photovoltaic devices. Finally, high efficiency of 12.73% is successfully achieved under fully open-air conditions. To the best of our knowledge, this is the first report of efficient PSCs with such a high humidity above 60%.

  17. Computational Fluid Dynamic Analysis of the Posterior Airway Space After Maxillomandibular Advancement For Obstructive Sleep Apnea Syndrome

    PubMed Central

    Sittitavornwong, Somsak; Waite, Peter D.; Shih, Alan M.; Cheng, Gary C.; Koomullil, Roy; Ito, Yasushi; Cure, Joel K; Harding, Susan M.; Litaker, Mark

    2013-01-01

    Purpose Evaluate the soft tissue change of the upper airway after maxillomandibular advancement (MMA) by computational fluid dynamics (CFD). Materials and Methods Eight OSAS patients who required MMA were recruited into this study. All participants had pre- and post-operative computed tomography (CT) and underwent MMA by a single oral and maxillofacial surgeon. Upper airway CT data sets for these 8 participants were created with high-fidelity 3-D numerical models for computational fluid dynamics (CFD). The 3-D models were simulated and analyzed to study how changes in airway anatomy affects pressure effort required for normal breathing. Airway dimensions, skeletal changes, Apnea-Hypopnea Index (AHI), and pressure efforts of pre- and post-operative 3-D models were compared and correlations interpreted. Results After MMA, laminar and turbulent air flow was significantly decreased at every level of the airway. The cross-sectional areas at the soft palate and tongue base were significantly increased. Conclusions This study shows that MMA increases airway dimensions by the increasing the occipital base (Base) - pogonion (Pg) distance. An increase of the Base-Pg distance showed a significant correlation with an AHI improvement and a decreased pressure effort of the upper airway. Decreasing the pressure effort will decrease the breathing workload. This improves the condition of OSAS. PMID:23642544

  18. Is I-gel airway a better option to endotracheal tube airway for sevoflurane-fentanyl anesthesia during cardiac surgery?

    PubMed Central

    Elgebaly, Ahmed Said; Eldabaa, Ahmed Ali

    2014-01-01

    Background: Anesthetists used lower doses of fentanyl, successfully with hemodynamic control by titrating volatile anesthetic agents or vasodilators for fast-tracking in cardiac surgery. Hypothesis: Lower total doses of anesthetics and fentanyl could be required with hemodynamic control by use of supraglottic devices than endotracheal tube (ETT) and helps in fast-tracking. Design: A prospective randomized observational clinical trial study. Aims: The authors compared the utility of I-gel airway with a conventional ETT during the induction and maintenance of anesthesia with sevoflurane and fentanyl in adults undergoing cardiac surgery. Patients and Methods: A total of 49 adult patients underwent cardiac surgery were randomized into two groups according to the airway management: I-gel group (n = 23) and ETT group (n = 26). Doses of fentanyl and hemodynamic parameters (heart rate [HR], mean arterial pressure [MAP] central venous pressure [CVP], pulmonary artery pressure [PAP], and pulmonary capillary wedge pressure [PCWP]) were recorded preoperative, 5 min following tracheal intubation or I-gel airway insertion, after skin incision, after stenotomy, and after weaning off bypass. Results: None of the patients in the I-gel group required additional doses of fentanyl during the I-gel insertion, compared with 74% of the patients during laryngoscopy and endotracheal insertion in the ETT group, for an average total dose of 22.6 ± 0.6 μg/kg. The MAP and HR did not significantly differ from the baseline values at any point of measurement in either group. Furthermore, CVP, PAP, and PCWP measured during the procedure were significantly lower in I-gel group than ETT group. Extubation required more amount of time in ETT than I- gel group. Conclusion: The I-gel airway is well-tolerated by adult patients undergoing cardiac surgery, and requires lower total doses of anesthetics than endotracheal intubation with hemodynamic control and helps in fast-tracking. PMID:25886229

  19. A pilot study to examine the effect of the Tulip oropharyngeal airway on ventilation immediately after mask ventilation following the induction of anaesthesia.

    PubMed

    Robinson, P N; Shaikh, A; Sabir, N M; Vaughan, D J A; Kynoch, M; Hasan, M

    2014-07-01

    The Tulip airway is an adult, disposable, single-sized oropharyngeal airway, that is connectable to an anaesthetic circuit. After a standardised induction of anaesthesia in 75 patients, the ease of insertion, intracuff pressure and intracuff volume were measured, as were the end-tidal carbon dioxide levels, airway pressures and tidal volumes over three breaths. Successful first-time insertion was achieved in 72 patients (96%, CI 88.8-99.2%) and after two attempts in 74 patients (99%, CI 92.8-100%). There was outright failure only in one patient. In 60 patients (80%, CI 72.2-90.4%), the Tulip airway provided a patent airway without additional manoeuvres, but in 14 patients, jaw thrust or head extension was necessary for airway patency. The main need for these adjuncts appeared to be an initial under-inflation of the cuff. These promising results are consistent with recent manikin studies using this device.

  20. Positive expiratory pressure and oscillatory positive expiratory pressure therapies.

    PubMed

    Myers, Timothy R

    2007-10-01

    Airway clearance techniques, historically referred to as chest physical therapy, have traditionally consisted of a variety of breathing maneuvers or exercises and manual percussion and postural drainage. The methods and types of airway clearance techniques and devices have rapidly increased in an effort to find a more efficacious strategy that allows for self-therapy, better patient adherence and compliance, and more efficient durations of care. Mechanically applied pressure devices have migrated from European countries over the last several decades to clinical practice in the United States. I conducted a comprehensive MEDLINE search of two such devices: positive expiratory pressure (PEP) and oscillatory positive expiratory pressure (OPEP) and their role in airway clearance strategies. This was followed by a comprehensive search for cross-references in an attempt to identify additional studies. The results of that search are contained and reported in this review. From a methods standpoint, most of the studies of PEP and OPEP for airway clearance are limited by crossover designs and small sample sizes. While PEP and OPEP do not definitively prove superiority to other methods of airway clearance strategies, there is no clear evidence that they are inferior. Ultimately, the correct choice may be an airway clearance strategy that is clinically and cost effective, and is preferred by the patient so that adherence and compliance can be at the very least supported.

  1. Effects of Ipragliflozin on Diabetic Nephropathy and Blood Pressure in Patients With Type 2 Diabetes: An Open-Label Study

    PubMed Central

    Ito, Daisuke; Ikuma-Suwa, Emi; Inoue, Kazuyuki; Kaneko, Kimie; Yanagisawa, Morifumi; Inukai, Kouichi; Noda, Mitsuhiko; Shimada, Akira

    2017-01-01

    Background Sodium-glucose cotransporter 2 (SGLT2) inhibitors are novel agents used to treat type 2 diabetic patients. We investigated the efficacy of the SGLT2 inhibitor ipragliflozin on diabetic nephropathy in Japanese patients with type 2 diabetes. Methods A 50 mg dose of ipragliflozin was administered for 24 weeks to 50 patients with type 2 diabetes who were concomitantly managed with diet and exercise therapy alone or antidiabetic medications other than SGLT2 inhibitors. Results At the end of the 24-week ipragliflozin treatment, significant decreases in mean glycated hemoglobin (HbA1c) (1.0±1.2%) and body weight (2.7 ± 2.5 kg) were observed; in addition, median urinary albumin-to-creatinine ratio (UACR) significantly decreased from 15.5 (8.0 - 85.7) to 12.9 (7.4 - 36.3) mg/gCr. Sub-analysis by renal function at baseline revealed that median UACR in patients with estimated glomerular filtration rate (eGFR) ≥ 90 mL/min/1.73 m2 decreased significantly from 12.3 (7.5 - 89.6) to 10.6 (5.8 - 27.3) mg/gCr. Furthermore, mean eGFR decreased significantly from 102.4 ± 8.6 to 93.6 ± 10.5 mL/min/1.73 m2 in these patients. In contrast, UACR and eGFR did not change significantly in patients with eGFR < 90. In addition, analysis of the relationship between the amount of change in UACR and blood pressure at 24 weeks revealed a significant positive correlation between UACR and SBP values, independently of the presence of diabetic nephropathy. Conclusions Our results indicate that ipragliflozin may facilitate HbA1c control and body weight reduction. Furthermore, our results also raise the possibility that ipragliflozin significantly reduces urinary albumin levels and improves glomerular hyperfiltration in a subset of patients with type 2 diabetes. PMID:28090231

  2. First-line treatment for elevated intraocular pressure (IOP) associated with open-angle glaucoma or ocular hypertension: focus on bimatoprost

    PubMed Central

    Law, Simon K

    2007-01-01

    The goal of treatment for open-angle glaucoma or ocular hypertension is to improve quality of life through reduction of intraocular pressure (IOP) to preserve visual function. Prostaglandins, as a newer class of ocular hypotensive agents, have been shown to be effective in IOP reduction by the primary mechanism of action of increase the uveoscleral outflow. Bimatoprost is a member this class, but different from the other members by having an ethyl amide group rather than an isopropyl ester at the C-1 carbon of the alpha chain. Bimatoprost used once daily has been shown to be more effect in IOP reduction than other classes of topical ocular hypotensive agents including beta-blockers, carbonic anhydrase inhibitors, and alpha agonists. Comparing with other topical prostaglandins, bimatoprost may be slightly more effective in IOP reduction, but the clinical significance is uncertain. The commonly reported adverse events associated with bimatoprost are localized to the eye and include conjunctival hyperemia, changes in the pigmentation of the periocular skin and iris, and eyelash darkening and growth. It is currently approved by the Food and Drug Administration (FDA) and the European Commission (EC) for first-line therapy for the reduction of elevated IOP in patients with open-angle glaucoma or ocular hypertension. PMID:19668476

  3. Stacking open-capillary electroosmotic pumps in series to boost the pumping pressure to drive high-performance liquid chromatographic separations.

    PubMed

    He, Chiyang; Zhu, Zaifang; Gu, Congying; Lu, Joann; Liu, Shaorong

    2012-03-02

    Numerous micropumps have been developed, but few of them can produce adequate flow rate and pressure for high-performance liquid chromatography (HPLC) applications. We have recently developed an innovative hybrid electroosmotic pump (EOP) to solve this problem. The basic unit of a hybrid pump consists of a +EOP (the pumping element is positively charged) and a -EOP (the pumping element is negatively charged). The outlet of the +EOP is then joined with the inlet of the -EOP, forming a basic pump unit, while the anode of a positive high voltage (HV) power supply is placed at the joint. The inlet and outlet of this pump unit are electrically grounded. With this configuration, we can stack many of such pump units in series to boost the pumping power. In this work, we describe in details how an open-capillary hybrid EOP is constructed and characterize this pump systematically. We also show that a hybrid EOP with ten serially stacked pump units can deliver a maximum pressure of 21.5 MPa (∼3100 psi). We further demonstrate the feasibility of using this hybrid EOP to drive eluents for HPLC separations of proteins and peptides.

  4. Sensory stimulation for lowering intraocular pressure, improving blood flow to the optic nerve and neuroprotection in primary open-angle glaucoma.

    PubMed

    Rom, Edith

    2013-12-01

    Primary open-angle glaucoma is a group of optic neuropathies that can lead to irreversible blindness. Sensory stimulation in the form of acupuncture or ear acupressure may contribute to protecting patients from blindness when used as a complementary method to orthodox treatment in the form of drops, laser or surgery. The objective of this article is to provide a narrative overview of the available literature up to July 2012. It summarises reported evidence on the potential beneficial effects of sensory stimulation for glaucoma. Sensory stimulation appears to significantly enhance the pressure-lowering effect of orthodox treatments. Studies suggest that it may also improve blood flow to the eye and optic nerve head. Furthermore, it may play a role in neuroprotection through regulating nerve growth factor and brain-derived neurotrophic factor and their receptors, thereby encouraging the survival pathway in contrast to the pathway to apoptosis. Blood flow and neuroprotection are areas that are not directly influenced by orthodox treatment modalities. Numerous different treatment protocols were used to investigate the effect of sensory stimulation on intraocular pressure, blood flow or neuroprotection of the retina and optic nerve in the animal model and human pilot studies. Objective outcomes were reported to have been evaluated with Goldmann tonometry, Doppler ultrasound techniques and electrophysiology (pattern electroretinography, visually evoked potentials), and supported with histological studies in the animal model. Taken together, reported evidence from these studies strongly suggests that sensory stimulation is worthy of further research.

  5. Stacking open-capillary electroosmotic pumps in series to boost the pumping pressure to drive high-performance liquid chromatographic separations

    DOE PAGES

    He, Chiyang; Zhu, Zaifang; Gu, Congying; ...

    2012-01-09

    Numerous micropumps have been developed, but few of them can produce adequate flow rate and pressure for high-performance liquid chromatography (HPLC) applications. We have recently developed an innovative hybrid electroosmotic pump (EOP) to solve this problem. The basic unit of a hybrid pump consists of a +EOP (the pumping element is positively charged) and a -EOP (the pumping element is negatively charged). The outlet of the +EOP is then joined with the inlet of the -EOP, forming a basic pump unit, while the anode of a positive high voltage (HV) power supply is placed at the joint. The inlet andmore » outlet of this pump unit are electrically grounded. With this configuration, we can stack many of such pump units in series to boost the pumping power. In this work, we describe in details how an open-capillary hybrid EOP is constructed and characterize this pump systematically. We also show that a hybrid EOP with ten serially stacked pump units can deliver a maximum pressure of 21.5 MPa (~3100 psi). Here, we further demonstrate the feasibility of using this hybrid EOP to drive eluents for HPLC separations of proteins and peptides.« less

  6. Stacking open-capillary electroosmotic pumps in series to boost the pumping pressure to drive high-performance liquid chromatographic separations

    SciTech Connect

    He, Chiyang; Zhu, Zaifang; Gu, Congying; Lu, Joann; Liu, Shaorong

    2012-01-09

    Numerous micropumps have been developed, but few of them can produce adequate flow rate and pressure for high-performance liquid chromatography (HPLC) applications. We have recently developed an innovative hybrid electroosmotic pump (EOP) to solve this problem. The basic unit of a hybrid pump consists of a +EOP (the pumping element is positively charged) and a -EOP (the pumping element is negatively charged). The outlet of the +EOP is then joined with the inlet of the -EOP, forming a basic pump unit, while the anode of a positive high voltage (HV) power supply is placed at the joint. The inlet and outlet of this pump unit are electrically grounded. With this configuration, we can stack many of such pump units in series to boost the pumping power. In this work, we describe in details how an open-capillary hybrid EOP is constructed and characterize this pump systematically. We also show that a hybrid EOP with ten serially stacked pump units can deliver a maximum pressure of 21.5 MPa (~3100 psi). Here, we further demonstrate the feasibility of using this hybrid EOP to drive eluents for HPLC separations of proteins and peptides.

  7. The Lung Microbiome and Airway Disease.

    PubMed

    Lynch, Susan V

    2016-12-01

    A growing body of literature has demonstrated relationships between the composition of the airway microbiota (mixed-species communities of microbes that exist in the respiratory tract) and critical features of immune response and pulmonary function. These studies provide evidence that airway inflammatory status and capacity for repair are coassociated with specific taxonomic features of the airway microbiome. Although directionality has yet to be established, the fact that microbes are known drivers of inflammation and tissue damage suggests that in the context of chronic inflammatory airway disease, the composition and, more importantly, the function, of the pulmonary microbiome represent critical factors in defining airway disease outcomes.

  8. Airway nerves: in vitro electrophysiology.

    PubMed

    Fox, Alyson

    2002-06-01

    Recording the activity of single airway sensory fibres or neuronal cell bodies in vitro has allowed detailed characterisation of fibre types and membrane properties. Fibre types can be identified by their conduction velocities and further studied by the application of drugs to their receptive field. C-fibres are sensitive to mechanical stimuli and a range of irritant chemicals (bradykinin, capsaicin, low pH, platelet-activating factor), whereas Adelta-fibres are relatively insensitive to chemical stimuli and appear to correlate to the rapidly adapting receptors identified in airways in vivo. Their site of origin also differs: upper airway C-fibres arise predominantly from the jugular ganglion and Adelta-fibres from the jugular and nodose ganglia. Intracellular recording from cell bodies in the ganglia has revealed a calcium-dependent potassium current common to many putative C-fibre cell bodies. This slow after hyperpolarisation current may be inhibited by stimuli that excite and sensitise C-fibres - this could be an important mechanism underlying the sensitisation of C-fibres in airway irritability.

  9. Republication: All India Difficult Airway Association 2016 Guidelines for Tracheal Intubation in the Intensive Care Unit

    PubMed Central

    Myatra, Sheila Nainan; Ahmed, Syed Moied; Kundra, Pankaj; Garg, Rakesh; Ramkumar, Venkateswaran; Patwa, Apeksh; Shah, Amit; Raveendra, Ubaradka S.; Shetty, Sumalatha Radhakrishna; Doctor, Jeson Rajan; Pawar, Dilip K.; Ramesh, Singaravelu; Das, Sabyasachi; Divatia, Jigeeshu Vasishtha

    2017-01-01

    Tracheal intubation (TI) is a routine procedure in the Intensive Care Unit (ICU) and is often lifesaving. In contrast to the controlled conditions in the operating room, critically ill patients with respiratory failure and shock are physiologically unstable. These factors, along with under evaluation of the airway and suboptimal response to preoxygenation, are responsible for a high incidence of life-threatening complications such as severe hypoxemia and cardiovascular collapse during TI in the ICU. The All India Difficult Airway Association (AIDAA) proposes a stepwise plan for safe management of the airway in critically ill patients. These guidelines have been developed based on available evidence; Wherever, robust evidence was lacking, recommendations were arrived at by consensus opinion of airway experts, incorporating the responses to a questionnaire sent to members of the (AIDAA) and Indian Society of Anaesthesiologists. Noninvasive positive pressure ventilation for preoxygenation provides adequate oxygen stores during TI for patients with respiratory pathology. Nasal insufflation of oxygen at 15 L/min can increase the duration of apnea before hypoxemia sets in. High flow nasal cannula oxygenation at 60–70 L/min may also increase safety during intubation of critically ill patients. Stable hemodynamics and gas exchange must be maintained during rapid sequence induction. It is necessary to implement an intubation protocol during routine airway management in the ICU. Adherence to a plan for difficult airway management incorporating the use of intubation aids and airway rescue devices and strategies is useful.

  10. Comparison of Reef Fish Survey Data Gathered by Open and Closed Circuit SCUBA Divers Reveals Differences in Areas With Higher Fishing Pressure

    PubMed Central

    Stamoulis, Kostantinos A.; Boland, Raymond C.; Lino, Kevin C.; Hauk, Brian B.; Leonard, Jason C.; Asher, Jacob M.; Lopes, Keolohilani H.; Kosaki, Randall K.

    2016-01-01

    Visual survey by divers using open-circuit (OC) SCUBA is the most widely used approach to survey coral reef fishes. Therefore, it is important to quantify sources of bias in OC surveys, such as the possibility that avoidance of OC divers by fishes can lead to undercounting in areas where targeted species have come to associate divers with a risk of being speared. One potential way to reduce diver avoidance is to utilize closed circuit rebreathers (CCRs), which do not produce the noise and bubbles that are a major source of disturbance associated with OC diving. For this study, we conducted 66 paired OC and CCR fish surveys in the Main Hawaiian Islands at locations with relatively high, moderate, and light fishing pressure. We found no significant differences in biomass estimates between OC and CCR surveys when data were pooled across all sites, however there were differences at the most heavily fished location, Oahu. There, biomass estimates from OC divers were significantly lower for several targeted fish groups, including surgeonfishes, targeted wrasses, and snappers, as well as for all targeted fishes combined, with mean OC biomass between 32 and 68% of mean CCR biomass. There were no clear differences between OC and CCR biomass estimates for these groups at sites with moderate or low fishing pressure, or at any location for other targeted fish groups, including groupers, parrotfishes, and goatfishes. Bias associated with avoidance of OC divers at heavily fished locations could be substantially reduced, or at least calibrated for, by utilization of CCR. In addition to being affected by fishing pressure, the extent to which avoidance of OC divers is problematic for visual surveys varies greatly among taxa, and is likely to be highly influenced by the survey methodology and dimensions used. PMID:27936044

  11. Comparison of Reef Fish Survey Data Gathered by Open and Closed Circuit SCUBA Divers Reveals Differences in Areas With Higher Fishing Pressure.

    PubMed

    Gray, Andrew E; Williams, Ivor D; Stamoulis, Kostantinos A; Boland, Raymond C; Lino, Kevin C; Hauk, Brian B; Leonard, Jason C; Rooney, John J; Asher, Jacob M; Lopes, Keolohilani H; Kosaki, Randall K

    2016-01-01

    Visual survey by divers using open-circuit (OC) SCUBA is the most widely used approach to survey coral reef fishes. Therefore, it is important to quantify sources of bias in OC surveys, such as the possibility that avoidance of OC divers by fishes can lead to undercounting in areas where targeted species have come to associate divers with a risk of being speared. One potential way to reduce diver avoidance is to utilize closed circuit rebreathers (CCRs), which do not produce the noise and bubbles that are a major source of disturbance associated with OC diving. For this study, we conducted 66 paired OC and CCR fish surveys in the Main Hawaiian Islands at locations with relatively high, moderate, and light fishing pressure. We found no significant differences in biomass estimates between OC and CCR surveys when data were pooled across all sites, however there were differences at the most heavily fished location, Oahu. There, biomass estimates from OC divers were significantly lower for several targeted fish groups, including surgeonfishes, targeted wrasses, and snappers, as well as for all targeted fishes combined, with mean OC biomass between 32 and 68% of mean CCR biomass. There were no clear differences between OC and CCR biomass estimates for these groups at sites with moderate or low fishing pressure, or at any location for other targeted fish groups, including groupers, parrotfishes, and goatfishes. Bias associated with avoidance of OC divers at heavily fished locations could be substantially reduced, or at least calibrated for, by utilization of CCR. In addition to being affected by fishing pressure, the extent to which avoidance of OC divers is problematic for visual surveys varies greatly among taxa, and is likely to be highly influenced by the survey methodology and dimensions used.

  12. Iptakalim inhibits PDGF-BB-induced human airway smooth muscle cells proliferation and migration.

    PubMed

    Liu, Wenrui; Kong, Hui; Zeng, Xiaoning; Wang, Jingjing; Wang, Zailiang; Yan, Xiaopei; Wang, Yanli; Xie, Weiping; Wang, Hong

    2015-08-15

    Chronic airway diseases are characterized by airway remodeling which is attributed partly to the proliferation and migration of airway smooth muscle cells (ASMCs). ATP-sensitive potassium (KATP) channels have been identified in ASMCs. Mount evidence has suggested that KATP channel openers can reduce airway hyperresponsiveness and alleviate airway remodeling. Opening K(+) channels triggers K(+) efflux, which leading to membrane hyperpolarization, preventing Ca(2+)entry through closing voltage-operated Ca(2+) channels. Intracellular Ca(2+) is the most important regulator of muscle contraction, cell proliferation and migration. K(+) efflux decreases Ca(2+) influx, which consequently influences ASMCs proliferation and migration. As a KATP channel opener, iptakalim (Ipt) has been reported to restrain the proliferation of pulmonary arterial smooth muscle cells (PASMCs) involved in vascular remodeling, while little is known about its impact on ASMCs. The present study was designed to investigate the effects of Ipt on human ASMCs and the mechanisms underlying. Results obtained from cell counting kit-8 (CCK-8), flow cytometry and 5-ethynyl-2'-deoxyuridine (EdU) incorporation showed that Ipt significantly inhibited platelet-derived growth factor (PDGF)-BB-induced ASMCs proliferation. ASMCs migration induced by PDGF-BB was also suppressed by Ipt in transwell migration and scratch assay. Besides, the phosphorylation of Ca(2+)/calmodulin-dependent kinase II (CaMKII), extracellular regulated protein kinases 1/2 (ERK1/2), protein kinase B (Akt), and cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) were as well alleviated by Ipt administration. Furthermore, we found that the inhibition of Ipt on the PDGF-BB-induced proliferation and migration in human ASMCs was blocked by glibenclamide (Gli), a selective KATP channel antagonist. These findings provide a strong evidence to support that Ipt antagonize the proliferating and migrating effects of PDGF-BB on

  13. Airway malacia in children with achondroplasia.

    PubMed

    Dessoffy, Kimberly E; Modaff, Peggy; Pauli, Richard M

    2014-02-01

    This study was undertaken to assess the frequency of airway malacia in infants and young children with achondroplasia, a population well known to be at risk for a variety of respiratory problems. We also wished to evaluate what, if any, contribution airway malacia makes to the complex respiratory issues that may be present in those with achondroplasia. Retrospective chart review of all infants and young children with achondroplasia who were assessed through the Midwest Regional Bone Dysplasia Clinics from 1985 through 2012 (n = 236) was completed. Records of comprehensive clinical examinations, polysomnographic assessments, and airway visualization were reviewed and abstracted using a data collection form. Analyses were completed comparing the group with and those without evidence for airway malacia. Thirteen of 236 patients (5.5%) were found to have airway malacia. Most of those affected had lower airway involvement (9/13). The presence of airway malacia was correlated with an increased occurrence of obstructive sleep apnea as well as need for oxygen supplementation, airway surgeries and tracheostomy placement. Although estimates of the frequency of airway malacia in the general population are limited, its frequency in children with achondroplasia appears to be much higher than any published general population estimate. The presence of airway malacia appears to confound other breathing abnormalities in this population and results in the need for more invasive airway treatments.

  14. Native Small Airways Secrete Bicarbonate

    PubMed Central

    Quinton, Paul M.

    2014-01-01

    Since the discovery of Cl− impermeability in cystic fibrosis (CF) and the cloning of the responsible channel, CF pathology has been widely attributed to a defect in epithelial Cl− transport. However, loss of bicarbonate (HCO3−) transport also plays a major, possibly more critical role in CF pathogenesis. Even though HCO3− transport is severely affected in the native pancreas, liver, and intestines in CF, we know very little about HCO3− secretion in small airways, the principle site of morbidity in CF. We used a novel, mini-Ussing chamber system to investigate the properties of HCO3− transport in native porcine small airways (∼ 1 mm φ). We assayed HCO3− transport across small airway epithelia as reflected by the transepithelial voltage, conductance, and equivalent short-circuit current with bilateral 25-mM HCO3− plus 125-mM NaGlu Ringer’s solution in the presence of luminal amiloride (10 μM). Under these conditions, because no major transportable anions other than HCO3− were present, we took the equivalent short-circuit current to be a direct measure of active HCO3− secretion. Applying selective agonists and inhibitors, we show constitutive HCO3− secretion in small airways, which can be stimulated significantly by β-adrenergic– (cAMP) and purinergic (Ca2+) -mediated agonists, independently. These results indicate that two separate components for HCO3− secretion, likely via CFTR- and calcium-activated chloride channel–dependent processes, are physiologically regulated for likely roles in mucus clearance and antimicrobial innate defenses of small airways. PMID:24224935

  15. Sarcoidosis of the upper and lower airways.

    PubMed

    Morgenthau, Adam S; Teirstein, Alvin S

    2011-12-01

    Sarcoidosis is a systemic granulomatous disease of undetermined etiology characterized by a variable clinical presentation and disease course. Although clinical granulomatous inflammation may occur within any organ system, more than 90% of sarcoidosis patients have lung disease. Sarcoidosis is considered an interstitial lung disease that is frequently characterized by restrictive physiologic dysfunction on pulmonary function tests. However, sarcoidosis also involves the airways (large and small), causing obstructive airways disease. It is one of a few interstitial lung diseases that affects the entire length of the respiratory tract - from the nose to the terminal bronchioles - and causes a broad spectrum of airways dysfunction. This article examines airway dysfunction in sarcoidosis. The anatomical structure of the airways is the organizational framework for our discussion. We discuss sarcoidosis involving the nose, sinuses, nasal passages, larynx, trachea, bronchi and small airways. Common complications of airways disease, such as, atelectasis, fibrosis, bullous leions, bronchiectasis, cavitary lesions and mycetomas, are also reviewed.

  16. Liquid plug propagation in flexible microchannels: A small airway model

    NASA Astrophysics Data System (ADS)

    Zheng, Y.; Fujioka, H.; Bian, S.; Torisawa, Y.; Huh, D.; Takayama, S.; Grotberg, J. B.

    2009-07-01

    In the present study, we investigate the effect of wall flexibility on the plug propagation and the resulting wall stresses in small airway models with experimental measurements and numerical simulations. Experimentally, a flexible microchannel was fabricated to mimic the flexible small airways using soft lithography. Liquid plugs were generated and propagated through the microchannels. The local wall deformation is observed instantaneously during plug propagation with the maximum increasing with plug speed. The pressure drop across the plug is measured and observed to increase with plug speed, and is slightly smaller in a flexible channel compared to that in a rigid channel. A computational model is then presented to model the steady plug propagation through a flexible channel corresponding to the middle plane in the experimental device. The results show qualitative agreements with experiments on wall shapes and pressure drops and the discrepancies bring up interesting questions on current field of modeling. The flexible wall deforms inward near the plug core region, the deformation and pressure drop across the plug increase with the plug speed. The wall deformation and resulting stresses vary with different longitudinal tensions, i.e., for large wall longitudinal tension, the wall deforms slightly, which causes decreased fluid stress and stress gradients on the flexible wall comparing to that on rigid walls; however, the wall stress gradients are found to be much larger on highly deformable walls with small longitudinal tensions. Therefore, in diseases such as emphysema, with more deformable airways, there is a high possibility of induced injuries on lining cells along the airways because of larger wall stresses and stress gradients.

  17. Comparative study of the microvascular blood flow in the intestinal wall, wound contraction and fluid evacuation during negative pressure wound therapy in laparostomy using the V.A.C. abdominal dressing and the ABThera open abdomen negative pressure therapy system.

    PubMed

    Lindstedt, Sandra; Malmsjö, Malin; Hlebowicz, Joanna; Ingemansson, Richard

    2015-02-01

    This study aimed to compare the changes in microvascular blood flow in the small intestinal wall, wound contraction and fluid evacuation, using the established V.A.C. abdominal dressing (VAC dressing) and a new abdominal dressing, the ABThera open abdomen negative pressure therapy system (ABThera dressing), in negative pressure wound therapy (NPWT). Midline incisions were made in 12 pigs that were subjected to treatment with NPWT using the VAC or ABThera dressing. The microvascular blood flow in the intestinal wall was measured before and after the application of topical negative pressures of −50, −75 and −125mmHg using laser Doppler velocimetry. Wound contraction and fluid evacuation were also measured. Baseline blood flow was defined as 100% in all settings. The blood flow was significantly reduced to 64·6±6·7% (P <0·05) after the application of −50mmHg using the VAC dressing, and to 65·3±9·6% (P <0·05) after the application of −50mmHg using the ABThera dressing. The blood flow was significantly reduced to 39·6±6·7% (P <0·05) after the application of −125mmHg using VAC and to 40·5±6·2% (P <0·05) after the application of −125mmHg using ABThera. No significant difference in reduction in blood flow could be observed between the two groups. The ABThera system afforded significantly better fluid evacuation from the wound, better drainage of the abdomen and better wound contraction than the VAC dressing.

  18. Airway remodeling in asthma: what really matters.

    PubMed

    Fehrenbach, Heinz; Wagner, Christina; Wegmann, Michael

    2017-03-01

    Airway remodeling is generally quite broadly defined as any change in composition, distribution, thickness, mass or volume and/or number of structural components observed in the airway wall of patients relative to healthy individuals. However, two types of airway remodeling should be distinguished more clearly: (1) physiological airway remodeling, which encompasses structural changes that occur regularly during normal lung development and growth leading to a normal mature airway wall or as an acute and transient response to injury and/or inflammation, which ultimately results in restoration of a normal airway structures; and (2) pathological airway remodeling, which comprises those structural alterations that occur as a result of either disturbed lung development or as a response to chronic injury and/or inflammation leading to persistently altered airway wall structures and function. This review will address a few major aspects: (1) what are reliable quantitative approaches to assess airway remodeling? (2) Are there any indications supporting the notion that airway remodeling can occur as a primary event, i.e., before any inflammatory process was initiated? (3) What is known about airway remodeling being a secondary event to inflammation? And (4), what can we learn from the different animal models ranging from invertebrate to primate models in the study of airway remodeling? Future studies are required addressing particularly pheno-/endotype-specific aspects of airway remodeling using both endotype-specific animal models and "endotyped" human asthmatics. Hopefully, novel in vivo imaging techniques will be further advanced to allow monitoring development, growth and inflammation of the airways already at a very early stage in life.

  19. Protocol for a randomised controlled trial of standard wound management versus negative pressure wound therapy in the treatment of adult patients with an open fracture of the lower limb: UK Wound management of Open Lower Limb Fractures (UK WOLFF)

    PubMed Central

    Achten, Juul; Parsons, Nick R; Bruce, Julie; Petrou, Stavros; Tutton, Elizabeth; Willett, Keith; Lamb, Sarah E; Costa, Matthew L

    2015-01-01

    Introduction Patients who sustain open lower limb fractures have reported infection risks as high as 27%. The type of dressing applied after initial debridement could potentially affect this risk. In this trial, standard dressings will be compared with a new emerging treatment, negative pressure wound therapy, for patients with open lower limb fractures. Methods and analysis All adult patients presenting with an open lower limb fracture, with a Gustilo and Anderson (G&A) grade 2/3, will be considered for inclusion. 460 consented patients will provide 90% power to detect a difference of eight points in the Disability Rating Index (DRI) score at 12 months, at the 5% level. A randomisation sequence, stratified by trial centre and G&A grade, will be produced and administered by a secure web-based service. A qualitative substudy will assess patients’ experience of giving consent for the trial, and acceptability of trial procedures to patients and staff. Patients will have clinical follow-up in a fracture clinic up to a minimum of 12 months as per standard National Health Service (NHS) practice. Functional and quality of life outcome data will be collected using the DRI, SF12 and EQ-5D questionnaires at 3, 6, 9 and 12 months postoperatively. In addition, information will be requested with regards to resource use and any late complications or surgical interventions related to their injury. The main analysis will investigate differences in the DRI score at 1 year after injury, between the two treatment groups on an intention-to-treat basis. Tests will be two sided and considered to provide evidence for a significant difference if p values are less than 0.05. Ethics and dissemination Ethical approval was given by NRES Committee West Midlands—Coventry & Warwickshire on 6/2/2012 (ref: 12/WM/0001). The results of the trial will be disseminated via peer-reviewed publications and presentations at relevant conferences. Trial registration number ISRCTN33756652. PMID

  20. Acute exposure to hair bleach causes airway hyperresponsiveness in a rabbit model.

    PubMed

    Mensing, T; Marek, W; Raulf-Heimsoth, M; Baur, X

    1998-12-01

    Ammonium persulphate (APS) and hydrogen peroxide (H2O2) are used as oxidants in many industrial processes and are the main constituents of standard hair bleaching products. In a previous study, it was demonstrated that aerosols of APS induce alterations in airway responsiveness. The present study examined whether exposure for 4 h to a hair bleach composition (containing APS, potassium persulphate and H2O2) or H2O2 could induce airway hyperresponsiveness and/or an obstructive ventilation pattern in a rabbit model. Exposure to the aerosols altered neither baseline airway resistance, dynamic elastance, slope of inspiratory pressure generation nor arterial blood pressure and blood gas measurements. Similarly to APS, hair bleach aerosols containing > or =10.9 mg x m(-3) persulphate (ammonium and potassium salt) in air and > or =1.36 mg x m(-3) H2O2 in air caused airway hyperresponsiveness to acetylcholine after 4 h of exposure. Aerosolized H2O2 (> or =37 mg x m(-3) in air) did not influence airway responsiveness to acetylcholine. The results demonstrate that hair bleaching products containing persulphates dissolved in H2O2 cause airway hyperresponsiveness to acetylcholine in rabbits.

  1. Application of the laryngeal mask airway for anesthesia in three chimpanzees and one gibbon.

    PubMed

    Johnson, Jacob A; Atkins, Adrienne L; Heard, Darryl J

    2010-09-01

    Three pediatric chimpanzees and one pediatric gibbon were anesthetized for routine physical examination. Anesthesia was maintained with inhalant delivered via a laryngeal mask airway (LMA). The LMA was easy to insert, provided adequate control of the airway for ventilation, and caused no tracheal stimulation. No complications were observed. As compared with a face mask, the LMA has the advantage of a more secure airway; the ability to effectively ventilate the patient; less dead space, which leads to lower rebreathing of carbon dioxide; and less exposure of personnel to waste gases. As compared with an endotracheal tube, the LMA causes less airway trauma, is easier to place, and is less stimulating to the patient. The LMA should be considered for use in fasted non-human primates presented for procedures lasting less than 60 min where high peak inspiratory pressures are not needed.

  2. Plant and environment interactions: Growth and yield response of commercial bearing-age {open_quote}Casselman{close_quote} plum trees to various ozone partial pressures

    SciTech Connect

    Retzlaff, W.A.; Williams, L.E.; DeJong, T.M.

    1997-05-01

    Nursery stock of plum (Prunus salicina Lindel., cv. Casselman) was planted 1 Apr. 1988 in an experimental orchard at the Univ. of California Kearney Agricultural Center near Fresno, CA. Trees in this study were enclosed in open-top fumigation chambers on 1 May 1989, and exposed to three atmospheric ozone partial pressures (charcoal filtered air, ambient air, and ambient air + ozone) during the 1989 through 1992 growing seasons (typically 1 Apr. - 1 Nov.). A nonchamber treatment plot was used to assess chamber effects on tree performance. This study details the results of the exposures during the initial commercial bearing period (1991 through 1993) in this orchard. The mean 12-h (0800-2000 h Pacific Daylight Time [PDT]) ozone partial pressures during the experimental periods in the charcoal filtered, ambient, ambient + ozone, and nonchamber treatments averaged 0.031, 0.048, 0.091, and 0.056 {mu}Pa Pa{sup {minus}1} in 1991 and 1992, respectively. Fruit number per tree decreased as atmospheric ozone partial pressure increased from the charcoal filtered to ambient + ozone treatment, significantly affecting yield. Yield of plum trees averaged 23.6, 19.8, 13.7, and 17.9 kg tree{sup {minus}1} in 1991 and 1992 in the charcoal filtered, ambient, ambient + ozone, and nonchamber treatments, respectively. Only one out of the five original treatment plots was exposed to ozone treatments during the 1993 growing season. Yield of plum trees in this single replicate in 1993 was reduced by increased atmospheric ozone partial pressure. Yield of plum trees in the four remaining unexposed treatment plots in 1993 was 16.7, 17.9, and 16.0 kg tree{sup {minus}1} in the previous charcoal filtered, ambient, and ambient + ozone treatments respectively. The similarity in yield of the post-chamber treatments indicates that a change in air quality in the current growing season can affect yield of Casselman plum trees. 26 refs., 6 figs., 4 tabs.

  3. The effects of open lung ventilation on respiratory mechanics and haemodynamics in atelectatic infants after cardiopulmonary bypass.

    PubMed

    Cui, Q; Zhou, H; Zhao, R; Liu, J; Yang, X; Zhu, H; Zheng, Q; Gu, C; Yi, D

    2009-01-01

    Acute lung injury (ALI) frequently occurs in infants after cardiopulmonary bypass (CPB) surgery and it sometimes develops into acute respiratory distress syndrome in critically ill infants, which can be life threatening. This study investigated the effects of open lung ventilation on the haemodynamics and respiratory mechanics of 64 infants (34 males; 30 females) with a mean +/- SD age of 8.3 +/- 0.3 months who developed ALI following CPB surgery. Open lung ventilation significantly improved the respiratory mechanics and oxygenation parameters of the infants, including the partial pressure of oxygen in arterial blood (PaO(2)), the ratio of PaO(2)/FiO(2) (fraction of inspired oxygen), peak inspiratory pressure, static compliance and airway resistance. It is concluded that open lung ventilation can greatly improve oxygenation and respiratory mechanics in infants with ALI following CPB surgery.

  4. Validation of computational fluid dynamics methodology used for human upper airway flow simulations.

    PubMed

    Mylavarapu, Goutham; Murugappan, Shanmugam; Mihaescu, Mihai; Kalra, Maninder; Khosla, Sid; Gutmark, Ephraim

    2009-07-22

    An anatomically accurate human upper airway model was constructed from multiple magnetic resonance imaging axial scans. This model was used to conduct detailed Computational Fluid Dynamics (CFD) simulations during expiration, to investigate the fluid flow in the airway regions where obstruction could occur. An identical physical model of the same airway was built using stereo lithography. Pressure and velocity measurements were conducted in the physical model. Both simulations and experiments were performed at a peak expiratory flow rate of 200 L/min. Several different numerical approaches within the FLUENT commercial software framework were used in the simulations; unsteady Large Eddy Simulation (LES), steady Reynolds-Averaged Navier-Stokes (RANS) with two-equation turbulence models (i.e. k-epsilon, standard k-omega, and k-omega Shear Stress Transport (SST)) and with one-equation Spalart-Allmaras model. The CFD predictions of the average wall static pressures at different locations along the airway wall were favorably compared with the experimental data. Among all the approaches, standard k-omega turbulence model resulted in the best agreement with the static pressure measurements, with an average error of approximately 20% over all ports. The highest positive pressures were observed in the retroglossal regions below the epiglottis, while the lowest negative pressures were recorded in the retropalatal region. The latter is a result of the airflow acceleration in the narrow retropalatal region. The largest pressure drop was observed at the tip of the soft palate. This location has the smallest cross section of the airway. The good agreement between the computations and the experimental results suggest that CFD simulations can be used to accurately compute aerodynamic flow characteristics of the upper airway.

  5. Integrated care pathways for airway diseases (AIRWAYS-ICPs).

    PubMed

    Bousquet, J; Addis, A; Adcock, I; Agache, I; Agusti, A; Alonso, A; Annesi-Maesano, I; Anto, J M; Bachert, C; Baena-Cagnani, C E; Bai, C; Baigenzhin, A; Barbara, C; Barnes, P J; Bateman, E D; Beck, L; Bedbrook, A; Bel, E H; Benezet, O; Bennoor, K S; Benson, M; Bernabeu-Wittel, M; Bewick, M; Bindslev-Jensen, C; Blain, H; Blasi, F; Bonini, M; Bonini, S; Boulet, L P; Bourdin, A; Bourret, R; Bousquet, P J; Brightling, C E; Briggs, A; Brozek, J; Buhl, R; Bush, A; Caimmi, D; Calderon, M; Calverley, P; Camargos, P A; Camuzat, T; Canonica, G W; Carlsen, K H; Casale, T B; Cazzola, M; Cepeda Sarabia, A M; Cesario, A; Chen, Y Z; Chkhartishvili, E; Chavannes, N H; Chiron, R; Chuchalin, A; Chung, K F; Cox, L; Crooks, G; Crooks, M G; Cruz, A A; Custovic, A; Dahl, R; Dahlen, S E; De Blay, F; Dedeu, T; Deleanu, D; Demoly, P; Devillier, P; Didier, A; Dinh-Xuan, A T; Djukanovic, R; Dokic, D; Douagui, H; Dubakiene, R; Eglin, S; Elliot, F; Emuzyte, R; Fabbri, L; Fink Wagner, A; Fletcher, M; Fokkens, W J; Fonseca, J; Franco, A; Frith, P; Furber, A; Gaga, M; Garcés, J; Garcia-Aymerich, J; Gamkrelidze, A; Gonzales-Diaz, S; Gouzi, F; Guzmán, M A; Haahtela, T; Harrison, D; Hayot, M; Heaney, L G; Heinrich, J; Hellings, P W; Hooper, J; Humbert, M; Hyland, M; Iaccarino, G; Jakovenko, D; Jardim, J R; Jeandel, C; Jenkins, C; Johnston, S L; Jonquet, O; Joos, G; Jung, K S; Kalayci, O; Karunanithi, S; Keil, T; Khaltaev, N; Kolek, V; Kowalski, M L; Kull, I; Kuna, P; Kvedariene, V; Le, L T; Lodrup Carlsen, K C; Louis, R; MacNee, W; Mair, A; Majer, I; Manning, P; de Manuel Keenoy, E; Masjedi, M R; Melen, E; Melo-Gomes, E; Menzies-Gow, A; Mercier, G; Mercier, J; Michel, J P; Miculinic, N; Mihaltan, F; Milenkovic, B; Molimard, M; Momas, I; Montilla-Santana, A; Morais-Almeida, M; Morgan, M; N'Diaye, M; Nafti, S; Nekam, K; Neou, A; Nicod, L; O'Hehir, R; Ohta, K; Paggiaro, P; Palkonen, S; Palmer, S; Papadopoulos, N G; Papi, A; Passalacqua, G; Pavord, I; Pigearias, B; Plavec, D; Postma, D S; Price, D; Rabe, K F; Radier Pontal, F; Redon, J; Rennard, S; Roberts, J; Robine, J M; Roca, J; Roche, N; Rodenas, F; Roggeri, A; Rolland, C; Rosado-Pinto, J; Ryan, D; Samolinski, B; Sanchez-Borges, M; Schünemann, H J; Sheikh, A; Shields, M; Siafakas, N; Sibille, Y; Similowski, T; Small, I; Sola-Morales, O; Sooronbaev, T; Stelmach, R; Sterk, P J; Stiris, T; Sud, P; Tellier, V; To, T; Todo-Bom, A; Triggiani, M; Valenta, R; Valero, A L; Valiulis, A; Valovirta, E; Van Ganse, E; Vandenplas, O; Vasankari, T; Vestbo, J; Vezzani, G; Viegi, G; Visier, L; Vogelmeier, C; Vontetsianos, T; Wagstaff, R; Wahn, U; Wallaert, B; Whalley, B; Wickman, M; Williams, D M; Wilson, N; Yawn, B P; Yiallouros, P K; Yorgancioglu, A; Yusuf, O M; Zar, H J; Zhong, N; Zidarn, M; Zuberbier, T

    2014-08-01

    The objective of Integrated Care Pathways for Airway Diseases (AIRWAYS-ICPs) is to launch a collaboration to develop multi-sectoral care pathways for chronic respiratory diseases in European countries and regions. AIRWAYS-ICPs has strategic relevance to the European Union Health Strategy and will add value to existing public health knowledge by: 1) proposing a common framework of care pathways for chronic respiratory diseases, which will facilitate comparability and trans-national initiatives; 2) informing cost-effective policy development, strengthening in particular those on smoking and environmental exposure; 3) aiding risk stratification in chronic disease patients, using a common strategy; 4) having a significant impact on the health of citizens in the short term (reduction of morbidity, improvement of education in children and of work in adults) and in the long-term (healthy ageing); 5) proposing a common simulation tool to assist physicians; and 6) ultimately reducing the healthcare burden (emergency visits, avoidable hospitalisations, disability and costs) while improving quality of life. In the longer term, the incidence of disease may be reduced by innovative prevention strategies. AIRWAYSICPs was initiated by Area 5 of the Action Plan B3 of the European Innovation Partnership on Active and Healthy Ageing. All stakeholders are involved (health and social care, patients, and policy makers).

  6. Comparison of laryngeal mask airway use with endotracheal intubation during anesthesia of western lowland gorillas (Gorilla gorilla gorilla).

    PubMed

    Cerveny, Shannon N; D'Agostino, Jennifer J; Davis, Michelle R; Payton, Mark E

    2012-12-01

    The laryngeal mask airway is an alternative to endotracheal intubation that achieves control of the airway by creating a seal around the larynx with an inflatable cuff. This study compared use of the laryngeal mask airway with endotracheal intubation in anesthetized western lowland gorillas (Gorilla gorilla gorilla). Eight adult gorillas were immobilized for routine and diagnostic purposes for a total of nine anesthetic events. During each anesthetic event, gorillas were either intubated (n = 4; group A) or fitted with a laryngeal mask airway (n= 5; group B). Time required to place each airway device, physiologic parameters, and arterial blood gas were measured and compared between the two groups. There were no significant differences between the two groups for time required to place airway device, heart rate, hemoglobin oxygen saturation, end-tidal carbon dioxide, arterial partial pressure of carbon dioxide, or arterial pH between the two groups. Mean arterial partial pressure of oxygen was significantly greater in group B, 15 (group A: 94 +/- 44 mm Hg; group B: 408 +/- 36 mm Hg; P= 0.0025) and 45 (group A: 104 +/- 21 mm Hg; group B: 407 +/- 77 mm Hg; P = 0.0026) min after airway device placement. Mean respiratory rate was significantly greater in group A at multiple time points. Mean arterial pressure (group A: 129 +/- 16 mm Hg; group B: 60 +/- 8 mm Hg) and diastolic blood pressure (group A: 115 +/- 21 mm Hg; group B: 36 +/- 10 mm Hg) were significantly greater in group A at the time of airway device placement. The laryngeal mask airway maintained oxygenation and ventilation effectively in all gorillas and is a useful alternative to endotracheal intubation in western lowland gorillas.

  7. Generation of Pig Airways using Rules Developed from the Measurements of Physical Airways

    PubMed Central

    Azad, Md Khurshidul; Mansy, Hansen A.

    2017-01-01

    Background A method for generating bronchial tree would be helpful when constructing models of the tree for benchtop experiments as well as for numerical modeling of flow or sound propagation in the airways. Early studies documented the geometric details of the human airways that were used to develop methods for generating human airway tree. However, methods for generating animal airway tree are scarcer. Earlier studies suggested that the morphology of animal airways can be significantly different from that of humans. Hence, using algorithms for the human airways may not be accurate in generating models of animal airway geometry. Objective The objective of this study is to develop an algorithm for generating pig airway tree based on the geometric details extracted from the physical measurements. Methods In the current study, measured values of branch diameters, lengths and bifurcation angles and rotation of bifurcating planes were used to develop an algorithm that is capable of generating a realistic pig airway tree. Results The generation relations between parent and daughter branches were found to follow certain trends. The diameters and the length of different branches were dependent on airway generations while the bifurcation angles were primarily dependent on bifurcation plane rotations. These relations were sufficient to develop rules for generating a model of the pig large airways. Conclusion The results suggested that the airway tree generated from the algorithm can provide an approximate geometric model of pig airways for computational and benchtop studies. PMID:28255517

  8. Multiscale Analysis of a Collapsible Respiratory Airway

    NASA Astrophysics Data System (ADS)

    Ghadiali, Samir; Bell, E. David; Swarts, J. Douglas

    2006-11-01

    The Eustachian tube (ET) is a collapsible respiratory airway that connects the nasopharynx with the middle ear (ME). The ET normally exists in a collapsed state and must be periodically opened to maintain a healthy and sterile ME. Although the inability to open the ET (i.e. ET dysfunction) is the primary etiology responsible for several common ME diseases (i.e. Otitis Media), the mechanisms responsible for ET dysfunction are not well established. To investigate these mechanisms, we developed a multi-scale model of airflow in the ET and correlated model results with experimental data obtained in healthy and diseased subjects. The computational models utilized finite-element methods to simulate fluid-structure interactions and molecular dynamics techniques to quantify the adhesive properties of mucus glycoproteins. Results indicate that airflow in the ET is highly sensitive to both the dynamics of muscle contraction and molecular adhesion forces within the ET lumen. In addition, correlation of model results with experimental data obtained in diseased subjects was used to identify the biomechanical mechanisms responsible for ET dysfunction.

  9. Effect of an open tube in series with a packed capillary column on liquid chromatographic performance. The influence of particle diameter, temperature, and system pressure.

    PubMed

    Xu, Hongjuan; Weber, Stephen G

    2009-02-27

    A postcolumn reactor or a simple open tube connecting a capillary column to, for example, a mass spectrometer affects the performance of a capillary liquid chromatography system in two ways: stealing pressure from the column and adding band-spreading. This effect is especially intolerable in fast separations. Our calculations show that in the presence of a 25 microm radius postcolumn reactor, column (50 microm radius) efficiency (number of theoretical plates) is severely reduced by more than 75% with a t(0) of 10s and a particle diameter from 1 to 5 microm for unretained solutes at room temperature. Therefore, it is necessary to minimize the reactor's effect and to improve the column efficiency by optimizing postcolumn conditions. We derived an equation that defines the observed number of theoretical plates (N(obs)) taking into account the two effects stated above, which is a function of the maximum pressure P(m), the particle diameter d(p), the reactor radius a(r), the column radius a(c), the desired dead time t(0), the column temperature T and zone capacity factor k''. Poppe plots were obtained by calculations using this equation. The results show that for a t(0) shorter than 18s, a P(m) of 4000 psi, and a d(p) of 1.7 microm, a 5 microm radius reactor has to be used. Such a small reactor is difficult to fabricate. Fortunately, high temperature helps to minimize the reactor effect so that reactors with manageable radius (larger than 12.5 microm) can be used in many practical conditions. Furthermore, solute retention diminishes the influence of a postcolumn reactor. Thus, a 12.5 microm reactor supersedes a 5 microm reactor for retained solutes even at a t(0) of 5s (k''>3.8, or k'>2.0).

  10. Effect of angiotensin receptor blockade on central aortic systolic blood pressure in hypertensive Asians measured using radial tonometry: an open prospective cohort study

    PubMed Central

    Teong, Hui Hwang; Chin, Adeline Mei Lin; Sule, Ashish Anil; Tay, Jam Chin

    2016-01-01

    INTRODUCTION Central aortic systolic pressure (CASP) has been shown to be a stronger predictor of cardiovascular events than brachial blood pressure (BP). Different classes of drugs have differential effects on CASP and brachial BP. This open prospective cohort study aimed to observe changes in CASP (measured using radial tonometry) among hypertensive Asians after 12 weeks of treatment with valsartan, an angiotensin receptor blocker (ARB). METHODS Patients with treatment-naïve hypertension or uncontrolled hypertension who were on non-ARB therapy were eligible for inclusion. Patients with uncontrolled BP (i.e. ≥ 140/90 mmHg) received valsartan for 12 weeks. The patients’ brachial systolic and diastolic BP (SBP and DBP), and CASP changes were monitored using the BPro® watch. RESULTS The mean age of the 44 enrolled patients was 35 years. At baseline, the mean BP and CASP were 150.2/91.4 ± 10.6/9.4 mmHg and 136.3 ± 12.2 mmHg, respectively. Valsartan reduced SBP, DBP and CASP by 14.9 ± 10.7 mmHg, 10.9 ± 8.4 mmHg and 15.3 ± 10.9 mmHg, respectively (all p < 0.001). Every 1.0-mmHg reduction in brachial SBP resulted in a 0.8-mmHg reduction in CASP (p < 0.001). A CASP cut-off of 122.5 mmHg discriminated between controlled and uncontrolled BP (sensitivity 74%, specificity 88%). CONCLUSION Using radial tonometry, we demonstrated good correlation between CASP and brachial SBP reductions after 12 weeks of treatment with valsartan in our study cohort. Correlation analysis between CASP and SBP reductions may be useful for demonstrating whether a drug is able to lower CASP beyond lowering SBP. PMID:26875683

  11. Recent trends in airway management

    PubMed Central

    Karlik, Joelle; Aziz, Michael

    2017-01-01

    Tracheal intubation remains a life-saving procedure that is typically not difficult for experienced providers in routine conditions. Unfortunately, difficult intubation remains challenging to predict and intubation conditions may make the event life threatening. Recent technological advances aim to further improve the ease, speed, safety, and success of intubation but have not been fully investigated. Video laryngoscopy, though proven effective in the difficult airway, may result in different intubation success rates in various settings and in different providers’ hands. The rescue surgical airway remains a rarely used but critical skill, and research continues to investigate optimal techniques. This review highlights some of the new thoughts and research on these important topics. PMID:28299194

  12. Inhaled Bordetella pertussis vaccine decreases airway responsiveness in guinea pigs.

    PubMed

    Vargas, M H; Bazán-Perkins, B; Segura, P; Campos, M G; Selman, M; Montaño, L M

    1995-01-01

    Bordetella pertussis (BP) has been used as adjuvant for experimental animal immunization, but its effects on airway responsiveness are uncertain. Three groups of guinea pigs were used: animals with a single exposure to inhaled BP vaccine (strain 134, total dose 1.24 x 10(12) germs), animals submitted to a sensitization procedure through inhalation of ovalbumin plus BP, and healthy control animals. Four weeks after inhalation of BP or after the beginning of sensitization, dose- or concentration-response curves to histamine were constructed in vivo and in vitro (tracheal and parenchymal preparations). We found that BP alone produced lower responses to histamine than control guinea pigs in vivo (insufflation pressure, p = 0.0003) and in tracheal tissues (p = 0.04), but not in parenchymal preparations. Sensitization did not modify the responsiveness compared with their respective controls. These results suggest that some BP component(s), probably pertussis toxin, causes a long lasting airway hyporesponsiveness in guinea pigs.

  13. [Obstruction of the upper airways in humans and animal models].

    PubMed

    Schulz, R

    2010-07-01

    Obstructive sleep apnea (OSA) is caused by repetitive collapse of a narrow upper airway during sleep with the main risk factor being obesity. Apneas are followed by hypoxia, sympathetic activation, intrathoracic pressure swings and arousals. In most animal studies, only the cyclical pattern of hypoxia characteristic of OSA is simulated, however, more complex models have also been developed which additionally reflect the other pathophysiological changes associated with sleep-disordered breathing. These models have contributed to a deeper understanding of the cardiovascular and metabolic consequences of OSA. From other experiments the concept of the pharynx behaving like a collapsible tube, i. e. a Starling resistor, has emerged. Finally, the neurotransmitter modulation of upper airway muscle tone has been elucidated by using IN VIVO microdialysis of the caudal medulla of rats. It is hoped that findings from animal studies will in the future impact on the management of patients with OSA, in particular if they are non-compliant with CPAP therapy.

  14. High-throughput morphometric analysis of pulmonary airways in MSCT via a mixed 3D/2D approach

    NASA Astrophysics Data System (ADS)

    Ortner, Margarete; Fetita, Catalin; Brillet, Pierre-Yves; Pr"teux, Françoise; Grenier, Philippe

    2011-03-01

    Asthma and COPD are complex airway diseases with an increased incidence estimated for the next decade. Today, the mechanisms and relationships between airway structure/physiology and the clinical phenotype and genotype are not completely understood. We thus lack the tools to predict disease progression or therapeutic responses. One of the main causes is our limited ability to assess the complexity of airway diseases in large populations of patients with appropriate controls. Multi-slice computed tomography (MSCT) imaging opened the way to the non-invasive assessment of airway physiology and structure, but the use of such technology in large cohorts requires a high degree of automation of the measurements. This paper develops an investigation framework and the associated image quantification tools for high-throughput analysis of airways in MSCT. A mixed approach is proposed, combining 3D and cross-section measurements of the airway tree where the user-interaction is limited to the choice of the desired analysis patterns. Such approach relies on the fully-automated segmentation of the 3D airway tree, caliber estimation and visualization based on morphologic granulometry, central axis computation and tree segment selection, cross-section morphometry of airway lumen and wall, and bronchus longitudinal shape analysis for stenosis/bronciectasis detection and measure validation. The developed methodology has been successfully applied to a cohort of 96 patients from a multi-center clinical study of asthma control in moderate and persistent asthma.

  15. Partial airway obstruction following manufacturing defect in laryngeal mask airway (Laryngeal Mask Silken™).

    PubMed

    Jangra, Kiran; Malhotra, Surender Kumar; Saini, Vikas

    2014-10-01

    Laryngeal mask (LM) airway is commonly used for securing airway in day-care surgeries. Various problems have been described while using LM airway. Out of those, mechanical obstruction causing airway compromise is most common. Here, we describe a case report of 4-year-old child who had partial upper airway obstruction due to LM manufacturer's defect. There was a silicon band in upper one-third of shaft of LM airway. This band was made up of the same material as that of LM airway so it was not identifiable on external inspection of transparent shaft. We suggest that such as non-transparent laryngeal mask, a transparent LM airway should also be inspected looking inside the lumen with naked eyes or by using a probe to rule out any manufacturing defect before its insertion.

  16. The Allergic Airway Inflammation Repository--a user-friendly, curated resource of mRNA expression levels in studies of allergic airways.

    PubMed

    Gawel, D R; Rani James, A; Benson, M; Liljenström, R; Muraro, A; Nestor, C E; Zhang, H; Gustafsson, M

    2014-08-01

    Public microarray databases allow analysis of expression levels of candidate genes in different contexts. However, finding relevant microarray data is complicated by the large number of available studies. We have compiled a user-friendly, open-access database of mRNA microarray experiments relevant to allergic airway inflammation, the Allergic Airway Inflammation Repository (AAIR, http://aair.cimed.ike.liu.se/). The aim is to allow allergy researchers to determine the expression profile of their genes of interest in multiple clinical data sets and several experimental systems quickly and intuitively. AAIR also provides quick links to other relevant information such as experimental protocols, related literature and raw data files.

  17. Lung sound analysis helps localize airway inflammation in patients with bronchial asthma

    PubMed Central

    Shimoda, Terufumi; Obase, Yasushi; Nagasaka, Yukio; Nakano, Hiroshi; Ishimatsu, Akiko; Kishikawa, Reiko; Iwanaga, Tomoaki

    2017-01-01

    Purpose Airway inflammation can be detected by lung sound analysis (LSA) at a single point in the posterior lower lung field. We performed LSA at 7 points to examine whether the technique could identify the location of airway inflammation in patients with asthma. Patients and methods Breath sounds were recorded at 7 points on the body surface of 22 asthmatic subjects. Inspiration sound pressure level (ISPL), expiration sound pressure level (ESPL), and the expiration-to-inspiration sound pressure ratio (E/I) were calculated in 6 frequency bands. The data were analyzed for potential correlation with spirometry, airway hyperresponsiveness (PC20), and fractional exhaled nitric oxide (FeNO). Results The E/I data in the frequency range of 100–400 Hz (E/I low frequency [LF], E/I mid frequency [MF]) were better correlated with the spirometry, PC20, and FeNO values than were the ISPL or ESPL data. The left anterior chest and left posterior lower recording positions were associated with the best correlations (forced expiratory volume in 1 second/forced vital capacity: r=−0.55 and r=−0.58; logPC20: r=−0.46 and r=−0.45; and FeNO: r=0.42 and r=0.46, respectively). The majority of asthmatic subjects with FeNO ≥70 ppb exhibited high E/I MF levels in all lung fields (excluding the trachea) and V50%pred <80%, suggesting inflammation throughout the airway. Asthmatic subjects with FeNO <70 ppb showed high or low E/I MF levels depending on the recording position, indicating uneven airway inflammation. Conclusion E/I LF and E/I MF are more useful LSA parameters for evaluating airway inflammation in bronchial asthma; 7-point lung sound recordings could be used to identify sites of local airway inflammation. PMID:28392708

  18. Computational modeling of unsteady surfactant-laden liquid plug propagation in neonatal airways

    NASA Astrophysics Data System (ADS)

    Olgac, Ufuk; Muradoglu, Metin

    2013-07-01

    Surfactant-free and surfactant-laden liquid plug propagation in neonatal airways in various generations representing the upper and lower airways are investigated computationally using a finite-difference/front-tracking method. Emphasis is placed on the unsteady surfactant-laden plug propagation as a model for Surfactant Replacement Therapy (SRT) and airway reopening. The numerical method is designed to solve the evolution equations of the interfacial and bulk surfactant concentrations coupled with the incompressible Navier-Stokes equations. Available experimental data for surfactant Survanta are used to relate surface tension coefficient to surfactant concentration at the interface. It is found that, for the surfactant-free case, the trailing film thickness is in good agreement with Taylor's law for plugs with plug length greater than the airway width. Mechanical stresses that could be injurious to epithelial cells such as pressure and shear stress and their gradients are maximized on the front and rear menisci with increasing magnitudes in the lower generations. These mechanical stresses, especially pressure and pressure gradient, are diminished with the introduction of surfactants. Surfactant is absorbed onto the trailing film and thickens it, eventually leading to either plug rupture or, if totally consumed prior to rupture, to steadily propagating plug. In the upper airways, initially small plugs rupture rapidly and plugs with comparable initial plug length with the airway width persist and propagate steadily. For a more effective SRT treatment, we recommend utilization of plugs with initial plug length greater than the airway width. Increasing surfactant strength or increasing the initially instilled surfactant concentration is found to be ineffective.

  19. A randomised trial to compare i-gel and ProSeal™ laryngeal mask airway for airway management in paediatric patients

    PubMed Central

    Nirupa, R; Gombar, Satinder; Ahuja, Vanita; Sharma, Preeti

    2016-01-01

    Background and Aims: i-gel™ is a newer supraglottic airway device with a unique non-inflatable cuff. We aimed to compare i-gel™ with ProSeal™ laryngeal mask airway (PLMA™) in children scheduled for surgery under general anaesthesia (GA) with controlled ventilation. Methods: This prospective, randomised controlled study was conducted in 100 surgical patients, aged 2–6 years of American Society of Anesthesiologists Physical Status I–II scheduled under GA. Patients were randomly allocated to receive either size 2 i-gel™ or PLMA™ as an airway device. The primary aim was oropharyngeal leak pressure assessed at 5 min following correct placement of the device. Secondary outcomes measured included number of attempts, ease of insertion, time of insertion, quality of initial airway, fibre-optic grading and effects on pulmonary mechanics. Statistical analysis was done using paired t-test and Chi-square test. Results: The demographic data were similar in both the groups. The oropharyngeal leak pressure in the i-gel™ group was 29.5 ± 2.5 cmH2 O as compared to 26.1 ± 3.8 cmH2 O in PLMA™ group (P = 0.002). The time taken for successful insertion in PLMA™ was longer as compared to i-gel (12.4 ± 2.7 vs. 10.2 ± 1.9 s, P = 0.007). The quality of initial airway was superior with i-gel™. The number of attempts, ease of insertion of supraglottic device, insertion of orogastric tube and pulmonary mechanics were similar in both the groups. Conclusion: Size 2 i-gel™ exhibited superior oropharyngeal leak pressure and quality of airway in paediatric patients with controlled ventilation as compared to PLMA™ although the pulmonary mechanics were similar. PMID:27761035

  20. Method for 3D Airway Topology Extraction

    PubMed Central

    Grothausmann, Roman; Kellner, Manuela; Heidrich, Marko; Lorbeer, Raoul-Amadeus; Ripken, Tammo; Meyer, Heiko; Kuehnel, Mark P.; Ochs, Matthias; Rosenhahn, Bodo

    2015-01-01

    In lungs the number of conducting airway generations as well as bifurcation patterns varies across species and shows specific characteristics relating to illnesses or gene variations. A method to characterize the topology of the mouse airway tree using scanning laser optical tomography (SLOT) tomograms is presented in this paper. It is used to test discrimination between two types of mice based on detected differences in their conducting airway pattern. Based on segmentations of the airways in these tomograms, the main spanning tree of the volume skeleton is computed. The resulting graph structure is used to distinguish between wild type and surfactant protein (SP-D) deficient knock-out mice. PMID:25767561

  1. Automated Lobe-Based Airway Labeling

    PubMed Central

    Gu, Suicheng; Wang, Zhimin; Siegfried, Jill M.; Wilson, David; Bigbee, William L.; Pu, Jiantao

    2012-01-01

    Regional quantitative analysis of airway morphological abnormalities is of great interest in lung disease investigation. Considering that pulmonary lobes are relatively independent functional unit, we develop and test a novel and efficient computerized scheme in this study to automatically and robustly classify the airways into different categories in terms of pulmonary lobe. Given an airway tree, which could be obtained using any available airway segmentation scheme, the developed approach consists of four basic steps: (1) airway skeletonization or centerline extraction, (2) individual airway branch identification, (3) initial rule-based airway classification/labeling, and (4) self-correction of labeling errors. In order to assess the performance of this approach, we applied it to a dataset consisting of 300 chest CT examinations in a batch manner and asked an image analyst to subjectively examine the labeled results. Our preliminary experiment showed that the labeling accuracy for the right upper lobe, the right middle lobe, the right lower lobe, the left upper lobe, and the left lower lobe is 100%, 99.3%, 99.3%, 100%, and 100%, respectively. Among these, only two cases are incorrectly labeled due to the failures in airway detection. It takes around 2 minutes to label an airway tree using this algorithm. PMID:23093951

  2. Anatomic Optical Coherence Tomography of Upper Airways

    NASA Astrophysics Data System (ADS)

    Chin Loy, Anthony; Jing, Joseph; Zhang, Jun; Wang, Yong; Elghobashi, Said; Chen, Zhongping; Wong, Brian J. F.

    The upper airway is a complex and intricate system responsible for respiration, phonation, and deglutition. Obstruction of the upper airways afflicts an estimated 12-18 million Americans. Pharyngeal size and shape are important factors in the pathogenesis of airway obstructions. In addition, nocturnal loss in pharyngeal muscular tone combined with high pharyngeal resistance can lead to collapse of the airway and periodic partial or complete upper airway obstruction. Anatomical optical coherence tomography (OCT) has the potential to provide high-speed three-dimensional tomographic images of the airway lumen without the use of ionizing radiation. In this chapter we describe the methods behind endoscopic OCT imaging and processing to generate full three dimensional anatomical models of the human airway which can be used in conjunction with numerical simulation methods to assess areas of airway obstruction. Combining this structural information with flow dynamic simulations, we can better estimate the site and causes of airway obstruction and better select and design surgery for patients with obstructive sleep apnea.

  3. 21 CFR 868.1750 - Pressure plethysmograph.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pressure plethysmograph. 868.1750 Section 868.1750...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1750 Pressure plethysmograph. (a) Identification. A pressure plethysmograph is a device used to determine a patient's airway resistance and...

  4. 21 CFR 868.1750 - Pressure plethysmograph.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pressure plethysmograph. 868.1750 Section 868.1750...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1750 Pressure plethysmograph. (a) Identification. A pressure plethysmograph is a device used to determine a patient's airway resistance and...

  5. 21 CFR 868.1750 - Pressure plethysmograph.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pressure plethysmograph. 868.1750 Section 868.1750...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1750 Pressure plethysmograph. (a) Identification. A pressure plethysmograph is a device used to determine a patient's airway resistance and...

  6. 21 CFR 868.1750 - Pressure plethysmograph.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Pressure plethysmograph. 868.1750 Section 868.1750...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1750 Pressure plethysmograph. (a) Identification. A pressure plethysmograph is a device used to determine a patient's airway resistance and...

  7. 21 CFR 868.1750 - Pressure plethysmograph.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pressure plethysmograph. 868.1750 Section 868.1750...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1750 Pressure plethysmograph. (a) Identification. A pressure plethysmograph is a device used to determine a patient's airway resistance and...

  8. Effect of ozone exposure on antigen-induced airway hyperresponsiveness in guinea pigs

    SciTech Connect

    Vargas, M.H.; Segura, P.; Campos, M.G.; Hong, E.; Montano, L.M.

    1994-12-31

    Airway hyperresponsiveness can be induced by several stimuli including antigen and ozone, both of which may be present in the air of polluted cities. Though the effect of ozone on the bronchoconstrictor response to antigen has been well described, the combined effect of these stimuli on airway hyperresponsiveness has not yet been studied. Sensitized guinea pigs with or without ozone exposure for 1 h at 3 ppm, 18 h prior to study, were challenged with a dose-response curve to histamine (0.01-1.8 {mu}g/kg, iv), and then by a second histamine dose-response curve 1 h later. Airway responses were measured as the increase in pulmonary insufflation pressure. In sensitized guinea pigs, the histamine ED50 significantly decreased after antigen challenge, demonstrating the development of airway hyperresponsiveness. Sensitized guinea pigs exposed to ozone showed airway hyperresponsiveness to histamine when compared with nonexposed animals, and such hyperresponsiveness was further enhanced after antigen challenge. We conclude that in this guinea pig model of acute allergic bronchoconstriction both antigen challenge and ozone induce airway hyperresponsiveness, while ozone exposure does not modify the development of antigen-induced hyperresponsiveness. 25 refs., 1 fig., 1 tab.

  9. Iptakalim inhibits PDGF-BB-induced human airway smooth muscle cells proliferation and migration

    SciTech Connect

    Liu, Wenrui; Kong, Hui; Zeng, Xiaoning; Wang, Jingjing; Wang, Zailiang; Yan, Xiaopei; Wang, Yanli; Xie, Weiping Wang, Hong

    2015-08-15

    Chronic airway diseases are characterized by airway remodeling which is attributed partly to the proliferation and migration of airway smooth muscle cells (ASMCs). ATP-sensitive potassium (K{sub ATP}) channels have been identified in ASMCs. Mount evidence has suggested that K{sub ATP} channel openers can reduce airway hyperresponsiveness and alleviate airway remodeling. Opening K{sup +} channels triggers K{sup +} efflux, which leading to membrane hyperpolarization, preventing Ca{sup 2+}entry through closing voltage-operated Ca{sup 2+} channels. Intracellular Ca{sup 2+} is the most important regulator of muscle contraction, cell proliferation and migration. K{sup +} efflux decreases Ca{sup 2+} influx, which consequently influences ASMCs proliferation and migration. As a K{sub ATP} channel opener, iptakalim (Ipt) has been reported to restrain the proliferation of pulmonary arterial smooth muscle cells (PASMCs) involved in vascular remodeling, while little is known about its impact on ASMCs. The present study was designed to investigate the effects of Ipt on human ASMCs and the mechanisms underlying. Results obtained from cell counting kit-8 (CCK-8), flow cytometry and 5-ethynyl-2′-deoxyuridine (EdU) incorporation showed that Ipt significantly inhibited platelet-derived growth factor (PDGF)-BB-induced ASMCs proliferation. ASMCs migration induced by PDGF-BB was also suppressed by Ipt in transwell migration and scratch assay. Besides, the phosphorylation of Ca{sup 2+}/calmodulin-dependent kinase II (CaMKII), extracellular regulated protein kinases 1/2 (ERK1/2), protein kinase B (Akt), and cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) were as well alleviated by Ipt administration. Furthermore, we found that the inhibition of Ipt on the PDGF-BB-induced proliferation and migration in human ASMCs was blocked by glibenclamide (Gli), a selective K{sub ATP} channel antagonist. These findings provide a strong evidence to support that Ipt

  10. The non-intubated anesthesia for airway surgery

    PubMed Central

    Nakanishi, Ryoichi

    2016-01-01

    Surgical treatment for lung cancer including airway resection following reconstruction is typically performed under general anesthesia with single-lung ventilation because it is necessary to maintain a sufficient working space and to adjust the airway pressure for the leak test. However, non-intubated thoracic surgery has been gradually developed in recent years for thoracoscopic surgery, due to its lower rate of postoperative complications, shorter hospitalization duration, and lower invasiveness than the usual single-lung anesthesia. Initially, only minor thoracoscopic surgery, including wedge resection for pneumothorax and the diagnosis of solitary pulmonary nodules, was performed under waking anesthesia. However, major thoracoscopic surgery, including segmentectomy and lobectomy, has also been performed under these conditions in some institutions due to its advantages with respect to the postoperative recovery and in-operating room time. In addition, non-intubated thoracic surgery has been performed for tracheal resection followed by reconstruction to fully explore the advantages of this surgical modality. In this article, the merits and demerits of non-intubated thoracoscopic surgery and the postoperative complications, perioperative problems and optimum selection criteria for patients for thoracic surgery (mainly airway surgery) are discussed. PMID:28066621

  11. The non-intubated anesthesia for airway surgery.

    PubMed

    Okuda, Katsuhiro; Nakanishi, Ryoichi

    2016-11-01

    Surgical treatment for lung cancer including airway resection following reconstruction is typically performed under general anesthesia with single-lung ventilation because it is necessary to maintain a sufficient working space and to adjust the airway pressure for the leak test. However, non-intubated thoracic surgery has been gradually developed in recent years for thoracoscopic surgery, due to its lower rate of postoperative complications, shorter hospitalization duration, and lower invasiveness than the usual single-lung anesthesia. Initially, only minor thoracoscopic surgery, including wedge resection for pneumothorax and the diagnosis of solitary pulmonary nodules, was performed under waking anesthesia. However, major thoracoscopic surgery, including segmentectomy and lobectomy, has also been performed under these conditions in some institutions due to its advantages with respect to the postoperative recovery and in-operating room time. In addition, non-intubated thoracic surgery has been performed for tracheal resection followed by reconstruction to fully explore the advantages of this surgical modality. In this article, the merits and demerits of non-intubated thoracoscopic surgery and the postoperative complications, perioperative problems and optimum selection criteria for patients for thoracic surgery (mainly airway surgery) are discussed.

  12. Peripheral airways obstruction in idiopathic pulmonary artery hypertension (primary).

    PubMed

    Fernandez-Bonetti, P; Lupi-Herrera, E; Martinez-Guerra, M L; Barrios, R; Seoane, M; Sandoval, J

    1983-05-01

    The mechanical properties of the lung were studied in ten nonsmokers with idiopathic pulmonary artery hypertension (IPAH) (mean pulmonary artery pressure 65.7 +/- 30 mm Hg). In the routine lung test, residual volume was found to be abnormal (greater than 120 percent of the predicted) in seven patients, and measured airway resistance was normal in eight out of the ten patients. A decreased FEF 75-85 percent, abnormal values for the helium-air flow ratios and increased closing capacities were documented in eight of ten patients in whom lung elastic recoil was normal (six of ten) or increased (four of ten). These features suggest peripheral airways obstruction (PAO) which was also supported by histopathologic findings in three cases (one biopsy and two necropsies). The observed changes in lung compliance could be related to the behavior of the coupling of the air-space and vascular compartments. The etiology of PAO in IPAH patients is not known, but our results indicate that both the peripheral airways and the pulmonary circulation are affected. The knowledge of PAO in IPAH patients could help to better understand the observed V/Q inequality in this entity.

  13. Transient motion of mucus plugs in respiratory airways

    NASA Astrophysics Data System (ADS)

    Zamankhan, Parsa; Hu, Yingying; Helenbrook, Brian; Takayama, Shuichi; Grotberg, James B.

    2011-11-01

    Airway closure occurs in lung diseases such as asthma, cystic fibrosis, or emphysema which have an excess of mucus that forms plugs. The reopening process involves displacement of mucus plugs in the airways by the airflow of respiration. Mucus is a non-Newtonian fluid with a yield stress; therefore its behavior can be approximated by a Bingham fluid constitutive equation. In this work the reopening process is approximated by simulation of a transient Bingham fluid plug in a 2D channel. The governing equations are solved by an Arbitrary Lagrangian Eulerian (ALE) finite element method through an in-house code. The constitutive equation for the Bingham fluid is implemented through a regularization method. The effects of the yield stress on the flow features and wall stresses are discussed with applications to potential injuries to the airway epithelial cells which form the wall. The minimum driving pressure for the initiation of the motion is computed and its value is related to the mucus properties and the plug shape. Supported by HL84370 and HL85156.

  14. Effect of hypoxia and hypercapina on the airways defence reflexes.

    PubMed

    Tatár, M; Tarkanov, I A; Korpás, J; Kulik, A M

    1987-01-01

    In experiments on 10 adult anaesthetized cats (pentobarbital 30 mg.kg-1 i.p.) the effect of stimultaneous hypoxia and hypercapnia was studied on the defence respiratory reflexes of the airways. Expiratory reflex and cough were elicited by mechanical stimulation of the airways mucosa, and the obtained values were evaluated on basis of the intrapleural pressure. Inhalation of the hypoxic-hypercapnic gas mixture (11% + 7% CO2 in N2) for 15 minutes led to a significant decrease of respiratory frequency, tidal volume and PaCO2, while pHa and PaCO2 also decreased significantly together with the intensity of the expiratory reflex and that of cough. Recent studies, showed that in the course of the effect of hypoxia (11% O2) and of hypercapnia (5% CO2), cough intensity decreased, but the change was not significant. The decrease of the intensity of respiratory defence reflexes under hypoxic-hypercapnic conditions might have been due to the changes of centrally controlling structures, or to the effector part of the reflex arc, resulting from fatigue of the respiratory muscles. The possible effect of anaesthesia exerting a significant influence on the intensity and character of airways defence reflexes could not be excluded.

  15. Airway management: induced tension pneumoperitoneum

    PubMed Central

    Ahmed, Khedher; Amine, El Ghali Mohamed; Abdelbaki, Azouzi; Jihene, Ayachi; Khaoula, Meddeb; Yamina, Hamdaoui; Mohamed, Boussarsar

    2016-01-01

    Pneumoperitoneum is not always associated with hollow viscus perforation. Such condition is called non-surgical or spontaneous pneumoperitoneum. Intrathoracic causes remain the most frequently reported mechanism inducing this potentially life threatening complication. This clinical condition is associated with therapeutic dilemma. We report a case of a massive isolated pneumoperitoneum causing acute abdominal hypertension syndrome, in a 75 year female, which occurred after difficult airway management and mechanical ventilation. Emergent laparotomy yielded to full recovery. The recognition of such cases for whom surgical management can be avoided is primordial to avoid unnecessary laparotomy and its associated morbidity particularly in the critically ill.

  16. Airway smooth muscle dynamics: a common pathway of airway obstruction in asthma.

    PubMed

    An, S S; Bai, T R; Bates, J H T; Black, J L; Brown, R H; Brusasco, V; Chitano, P; Deng, L; Dowell, M; Eidelman, D H; Fabry, B; Fairbank, N J; Ford, L E; Fredberg, J J; Gerthoffer, W T; Gilbert, S H; Gosens, R; Gunst, S J; Halayko, A J; Ingram, R H; Irvin, C G; James, A L; Janssen, L J; King, G G; Knight, D A; Lauzon, A M; Lakser, O J; Ludwig, M S; Lutchen, K R; Maksym, G N; Martin, J G; Mauad, T; McParland, B E; Mijailovich, S M; Mitchell, H W; Mitchell, R W; Mitzner, W; Murphy, T M; Paré, P D; Pellegrino, R; Sanderson, M J; Schellenberg, R R; Seow, C Y; Silveira, P S P; Smith, P G; Solway, J; Stephens, N L; Sterk, P J; Stewart, A G; Tang, D D; Tepper, R S; Tran, T; Wang, L

    2007-05-01

    Excessive airway obstruction is the cause of symptoms and abnormal lung function in asthma. As airway smooth muscle (ASM) is the effecter controlling airway calibre, it is suspected that dysfunction of ASM contributes to the pathophysiology of asthma. However, the precise role of ASM in the series of events leading to asthmatic symptoms is not clear. It is not certain whether, in asthma, there is a change in the intrinsic properties of ASM, a change in the structure and mechanical properties of the noncontractile components of the airway wall, or a change in the interdependence of the airway wall with the surrounding lung parenchyma. All these potential changes could result from acute or chronic airway inflammation and associated tissue repair and remodelling. Anti-inflammatory therapy, however, does not "cure" asthma, and airway hyperresponsiveness can persist in asthmatics, even in the absence of airway inflammation. This is perhaps because the therapy does not directly address a fundamental abnormality of asthma, that of exaggerated airway narrowing due to excessive shortening of ASM. In the present study, a central role for airway smooth muscle in the pathogenesis of airway hyperresponsiveness in asthma is explored.

  17. Down-regulation of 8-oxoguanine DNA glycosylase 1 expression in the airway epithelium ameliorates allergic lung inflammation.

    PubMed

    Bacsi, Attila; Aguilera-Aguirre, Leopoldo; Szczesny, Bartosz; Radak, Zsolt; Hazra, Tapas K; Sur, Sanjiv; Ba, Xueqing; Boldogh, Istvan

    2013-01-01

    Allergic airway inflammation is characterized by increased expression of pro-inflammatory mediators, inflammatory cell infiltration, mucus hypersecretion, and airway hyperresponsiveness, in parallel with oxidative DNA base and strand damage, whose etiological role is not understood. Our goal was to establish the role of 8-oxoguanine (8-oxoG), a common oxidatively damaged base, and its repair by 8-oxoguanine DNA glycosylase 1 (Ogg1) in allergic airway inflammatory processes. Airway inflammation was induced by intranasally administered ragweed (Ambrosia artemisiifolia) pollen grain extract (RWPE) in sensitized BALB/c mice. We utilized siRNA technology to deplete Ogg1 from airway epithelium; 8-oxoG and DNA strand break levels were quantified by Comet assays. Inflammatory cell infiltration and epithelial methaplasia were determined histologically, mucus and cytokines levels biochemically and enhanced pause was used as the main index of airway hyperresponsiveness. Decreased Ogg1 expression and thereby 8-oxoG repair in the airway epithelium conveyed a lower inflammatory response after RWPE challenge of sensitized mice, as determined by expression of Th2 cytokines, eosinophilia, epithelial methaplasia, and airway hyperresponsiveness. In contrast, 8-oxoG repair in Ogg1-proficient airway epithelium was coupled to an increase in DNA single-strand break (SSB) levels and exacerbation of allergen challenge-dependent inflammation. Decreased expression of the Nei-like glycosylases Neil1 and Neil2 that preferentially excise ring-opened purines and 5-hydroxyuracil, respectively, did not alter the above parameters of allergic immune responses to RWPE. These results show that DNA SSBs formed during Ogg1-mediated repair of 8-oxoG augment antigen-driven allergic immune responses. A transient modulation of OGG1 expression/activity in airway epithelial cells could have clinical benefits.

  18. Fixed combination of travoprost and timolol maleate reduces intraocular pressure in Japanese patients with primary open-angle glaucoma or ocular hypertension: analysis by prostaglandin analogue

    PubMed Central

    Nakano, Tadashi; Mizoue, Shiro; Fuse, Nobuo; Iwase, Aiko; Matsumoto, Shun; Yoshikawa, Keiji

    2017-01-01

    Background We have shown a decrease in mean intraocular pressure (IOP) by switching to travoprost/timolol fixed combination (TTFC) in subjects receiving prostaglandin analogue (PGA) monotherapy and requiring additional medication in a previous report. For analyzing factors affecting IOP reduction, baseline IOP and preceding PGA were selected as statistically and clinically significant factors. In this report, we examine IOP-lowering effect and adverse drug reactions by preceding PGA. Methods Patients with primary open angle glaucoma or ocular hypertension who received monotherapy with one of four PGAs (travoprost, latanoprost, tafluprost, or bimatoprost) for at least 3 months at 26 institutions and were determined to require additional medication by their primary physician were included. IOP reduction and adverse events were examined at 4, 8, and 12 weeks for each of four PGAs after switching to TTFC. Results In total, 157 patients who could be followed up for at least 4 weeks after switching to TTFC were included in the efficacy analysis. Multiple regression analysis was performed, and baseline IOP and PGA were found to be significant factors to IOP reduction. IOP reduction at week 12, adjusted with the regression model, was −3.5, −1.8, and −1.4 mmHg in the tafluprost, latanoprost, and travoprost groups, whereas it was −0.5 mmHg in the bimatoprost group. Along with differences in baseline IOP between groups, an IOP-lowering effect of >1 mmHg was noted in the tafluprost, latanoprost, and travoprost groups after the switch. IOP was maintained at 13.8–14.8 mmHg throughout the follow-up period. No serious adverse events or noteworthy issues were observed in any group after the switch. Conclusion Clinically significant IOP-reducing effects of TTFC were observed in the latanoprost, travoprost, and tafluprost groups when switching from each PGA monotherapy, while there were some differences in effects between groups, with minimal safety concerns. PMID:28053501

  19. Comparison of self-measured diurnal intraocular pressure profiles using rebound tonometry between primary angle closure glaucoma and primary open angle glaucoma patients

    PubMed Central

    Tan, Shaoying; Baig, Nafees; Hansapinyo, Linda; Jhanji, Vishal; Wei, Shihui; Tham, Clement C.

    2017-01-01

    Purpose To document the diurnal intraocular pressure (IOP) profile with rebound tonometry performed by primary glaucoma patients in non-clinic environment. Patients and methods Fifty-three medically-treated eyes of 31 primary angle closure glaucoma (PACG) and 22 primary open angle glaucoma (POAG) patients with no previous eye surgery were recruited. Diurnal IOP was measured 5 times per day at four-hourly intervals from 08:00 to 24:00 for 1 week in patients’ study eye using rebound tonometry in a non-clinic environment. The diurnal IOP profiles were compared between PACG and POAG eyes. Results For both PACG and POAG eyes, mean patient-measured IOP was highest in the morning, gradually decreased over the course of a day, and was lowest by midnight (p < 0.001). The diurnal IOP fluctuation ± 1 standard deviation (SD), as documented by SD in daily IOP values, was lower in PACG group (1.6 ± 1.1 mmHg) than in POAG group (2.0 ± 1.2 mmHg; p = 0.049). The mean trough IOP ± 1 SD was higher in PACG group (12.9 ± 2.8 mmHg), compared to POAG group (11.5 ± 3.8 mmHg; p = 0.041). The mean IOP level at midnight ± 1 SD in PACG group (14.0 ± 3.2 mmHg) was higher than that in POAG group (12.1 ± 3.7 mmHg; p = 0.013). Conclusions IOP in primary glaucoma patients was highest in the morning, and decreased over the course of a day in non-clinic environment. Treated diurnal IOP fluctuation seemed to be greater in POAG than PACG eyes. PMID:28333942

  20. Three Toxic Heavy Metals in Open-Angle Glaucoma with Low-Teen and High-Teen Intraocular Pressure: A Cross-Sectional Study from South Korea

    PubMed Central

    Lee, Si Hyung; Kang, Eun Min; Kim, Gyu Ah; Kwak, Seung Woo; Kim, Joon Mo; Bae, Hyoung Won; Seong, Gong Je; Kim, Chan Yun

    2016-01-01

    Background To investigate the association between heavy metal levels and open-angle glaucoma (OAG) with low- and high-teen baseline intraocular pressure (IOP) using a population-based study design. Methods This cross-sectional study included 5,198 participants older than 19 years of age who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) from 2008 to 2012 and had blood heavy metal levels available. The OAG with normal baseline IOP (IOP ≤ 21 mmHg) subjects were stratified into low-teen OAG (baseline IOP ≤ 15 mmHg) and high-teen OAG (15 mmHg < baseline IOP ≤ 21 mmHg), and the association between blood lead, mercury, and cadmium levels and glaucoma prevalence was assessed for low- and high-teen OAG. Results The adjusted geometric mean of blood cadmium levels was significantly higher in subjects with low-teen OAG than that of the non-glaucomatous group (P = 0.028), whereas there were no significant differences in blood lead and mercury levels. After adjusting for potential confounders, the low-teen OAG was positively associated with log-transformed blood cadmium levels (OR, 1.41; 95% confidence interval (CI), 1.03–1.93; P = 0.026). For high-teen OAG, log-transformed blood levels of the three heavy metals were not associated with disease prevalence. The association between log-transformed blood cadmium levels and low-teen OAG was significant only in men (OR, 1.65; 95% CI, 1.10–2.48; P = 0.016), and not in women (OR, 1.10; 95% CI, 0.66–1.85; P = 0.709). Conclusions The results of this study suggest that cadmium toxicity could play a role in glaucoma pathogenesis, particularly in men and in OAG with low-teen baseline IOP. PMID:27768724

  1. Extended analysis of constant-height hydraulic fractures for the estimation of in-situ crack-opening modulus from bottomhole pressure records

    SciTech Connect

    Wijesinghe, A.M.

    1987-03-01

    Hydraulic fractures created in oil and gas bearing rock formations can be made to propagate for a limited time at approximately constant height if favorable stress, deformation modulus or fracture toughness barriers to height growth exist and if the fracture design is suitably optimized to exploit these favorable conditions and reduce height growth. In this report, a unified theoretical formulation for the Perkins-Kern-Nordgren (PKN) and Christianovitch-Geertsma-De Klerk-Daneshy (CGDD) constant height fracture models is first presented. For a fracture fluid injection rate that varies as an arbitrary power of time, growth laws for fracturing fluid pressure, fracture width, and flow rate are rigorously derived for PKN and CGDD types of fractures. These similarity solutions account for non-Newtonian power-law fluid flow, transient fluid storage and generalized power-law fluid leak-off to the rock formation. They include and extend the results currently available in the literature for PKN and CGDD fractures. The results for PKN and CGDD fractures are then generalized to obtain an approximate hybrid CGDD-PKN fracture model that can be applied to constant height fractures of arbitrary length/height aspect ratio and arbitrary cross-sectional shape. Characteristic times for fracture extension are identified and estimates are given for the transition times when the fracture evolves from a CGDD-type fracture at small aspect ratio to a PKN-type fracture at large aspect ratio. These results are useful for interpreting fracturing data and for designing fractures for crack-opening modulus measurements.

  2. A randomised crossover trial comparing a single-use polyvinyl chloride laryngeal mask airway with a single-use silicone laryngeal mask airway.

    PubMed

    Bell, S F; Morris, N G; Rao, A; Wilkes, A R; Goodwin, N

    2012-12-01

    We compared insertion rates of single-use polyvinyl chloride laryngeal mask airways (LMAs) vs single-use silicone LMAs in 72 anaesthetised patients. Both airways were produced by Flexicare Medical. Laryngeal mask airway insertion was successful on the first attempt in 68/72 (94%) polyvinyl chloride LMAs vs 64/72 (89%) silicone LMAs (p = 0.39). Overall insertion rates were 72/72 (100%) for the polyvinyl chloride LMAs and 71/72 (99%) for the silicone LMAs (p = 1.0). Mean (SD) insertion times were similar for polyvinyl chloride and silicone LMAs: 24.3 (5.1)s vs 24.8 (7.8)s (p = 0.64). Laryngeal mask airway position, as assessed using a fibrescope, was not different (p = 0.077). The median (IQR [range]) leak pressure was 16 (12-20 [6-30]) cmH(2) O for the polyvinyl LMA and 18 (13-22 [6-30]) cmH(2) O or the silicone LMA (p = 0.037). In conclusion, we did not find any important differences between polyvinyl chloride and silicone laryngeal mask airways.

  3. Mechanisms of inflammation-mediated airway smooth muscle plasticity and airways remodeling in asthma.

    PubMed

    Halayko, Andrew J; Amrani, Yassine

    2003-09-16

    Recent evidence points to progressive structural change in the airway wall, driven by chronic local inflammation, as a fundamental component for development of irreversible airway hyperresponsiveness. Acute and chronic inflammation is orchestrated by cytokines from recruited inflammatory cells, airway myofibroblasts and myocytes. Airway myocytes exhibit functional plasticity in their capacity for contraction, proliferation, and synthesis of matrix protein and cytokines. This confers a principal role in driving different components of the airway remodeling process, and mediating constrictor hyperresponsiveness. Functional plasticity of airway smooth muscle (ASM) is regulated by an array of environmental cues, including cytokines, which mediate their effects through receptors and a number of intracellular signaling pathways. Despite numerous studies of the cellular effects of cytokines on cultured airway myocytes, few have identified how intracellular signaling pathways modulate or induce these cellular responses. This review summarizes current understanding of these concepts and presents a model for the effects of inflammatory mediators on functional plasticity of ASM in asthma.

  4. Comparison of the effects of bimatoprost and timolol on intraocular pressure and pulsatile ocular blood flow in patients with primary open-angle glaucoma: A prospective, open-label, randomized, two-arm, parallel-group study

    PubMed Central

    Vetrugno, Michele; Cardascia, Nicola; Cantatore, Francesco; Sborgia, Carlo

    2004-01-01

    Abstract Background: The current objective of antiglaucomatous therapy is to reduce intraocular pressure (IOP), and thus to preserve visual function. Many ophthalmologists believe this objective is best achieved by methods that improve ocular blood flow to the optic nerve head. Beta-blockers are effective ocular hypotensive agents, but they can reduce choroidal blood flow. Bimatoprost, a new prostamide analogue, has been shown to have a better IOP-lowering effect compared with the nonselective beta-adrenergic receptor blocker timolol maleate, but little is known about its effects on the vascular bed of the eye. Objective: The aim of this study was to compare the effects of bimatoprost and timolol on IOP and choroidal blood flow (as measured using pulsatile ocular blood flow [pOBF]) in patients with primary open-angle glaucoma (POAG). Methods: This prospective, open-label, randomized, 2-arm, parallel-group study was conducted at the Glaucoma Research Centre, Department of Ophthalmology, University Hospital of Bari, Bari, Italy. Patients with POAG having well-controlled IOP (<16 mm Hg) on monotherapy with timolol 0.5% ophthalmic solution (2 drops per affected eye BID) for ≥12 months but with a progressive decrease in pOBF during the same time period were randomly allocated to 1 of 2 treatment groups. One group continued monotherapy with timolol, 2 drops per affected eye BID. The other group was switched (without washout) to bimatoprost 0.3% ophthalmic solution (2 drops per affected eye QD [9 pm]). Treatment was given for 180 days. IOP and pOBF were assessed at the diagnostic visit (pre-timolol), baseline (day 0), and treatment days 15, 30, 60, 90, and 180. Primary adverse effects (AEs) (ie, conjunctival hyperemia, conjunctival papillae, stinging, burning, foreign body sensation, and pigmentation of periorbital skin) were monitored throughout the study. Results: Thirty-eight patients were enrolled (22 men, 16 women; mean [SD] age, 51.7 [4.8] years; 19 patients per

  5. 21 CFR 868.5110 - Oropharyngeal airway.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Oropharyngeal airway. 868.5110 Section 868.5110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5110 Oropharyngeal airway....

  6. 21 CFR 868.5100 - Nasopharyngeal airway.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nasopharyngeal airway. 868.5100 Section 868.5100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5100 Nasopharyngeal airway....

  7. SUBCHRONIC ENDOTOXIN INHALATION CAUSES PERSISTENT AIRWAY DISEASE

    EPA Science Inventory

    ABSTRACT

    The endotoxin component of organic dusts causes acute reversible airflow obstruction and airway inflammation. To test the hypothesis that endotoxin alone causes airway remodeling, we have compared the response of two inbred mouse strains to subchronic endotoxin ...

  8. Upper airway resistance: species-related differences.

    PubMed

    Kirschvink, N; Reinhold, P

    2010-07-01

    In veterinary medicine, upper airway resistance deserves a particular attention in equines athletes and brachycephalic dogs. Due to the anatomical peculiarities of the upper airway and/or pathological conditions, significant alterations of performance and/or well being might occur in horses and dogs. Physiological specificities and pathological changes of the lower respiratory tract deserve a major attention in other species.

  9. Airway and Extracellular Matrix Mechanics in COPD

    PubMed Central

    Bidan, Cécile M.; Veldsink, Annemiek C.; Meurs, Herman; Gosens, Reinoud

    2015-01-01

    Chronic obstructive pulmonary disease (COPD) is one of the most common lung diseases worldwide, and is characterized by airflow obstruction that is not fully reversible with treatment. Even though airflow obstruction is caused by airway smooth muscle contraction, the extent of airway narrowing depends on a range of other structural and functional determinants that impact on active and passive tissue mechanics. Cells and extracellular matrix in the airway and parenchymal compartments respond both passively and actively to the mechanical stimulation induced by smooth muscle contraction. In this review, we summarize the factors that regulate airway narrowing and provide insight into the relative contributions of different constituents of the extracellular matrix and their biomechanical impact on airway obstruction. We then review the changes in extracellular matrix composition in the airway and parenchymal compartments at different stages of COPD, and finally discuss how these changes impact airway narrowing and the development of airway hyperresponsiveness. Finally, we position these data in the context of therapeutic research focused on defective tissue repair. As a conclusion, we propose that future works should primarily target mild or early COPD, prior to the widespread structural changes in the alveolar compartment that are more characteristic of severe COPD. PMID:26696894

  10. Oscillations and noise: inherent instability of pressure support ventilation?

    PubMed

    Hotchkiss, John R; Adams, Alexander B; Stone, Mary K; Dries, David J; Marini, John J; Crooke, Philip S

    2002-01-01

    Pressure support ventilation (PSV) is almost universally employed in the management of actively breathing ventilated patients with acute respiratory failure. In this partial support mode of ventilation, a fixed pressure is applied to the airway opening, and flow delivery is monitored by the ventilator. Inspiration is terminated when measured inspiratory flow falls below a set fraction of the peak flow rate (flow cutoff); the ventilator then cycles to a lower pressure and expiration commences. We used linear and nonlinear mathematical models to investigate the dynamic behavior of pressure support ventilation and confirmed the predicted behavior using a test lung. Our mathematical and laboratory analyses indicate that pressure support ventilation in the setting of airflow obstruction can be accompanied by marked variations in tidal volume and end-expiratory alveolar pressure, even when subject effort is unvarying. Unstable behavior was observed in the simplest plausible linear mathematical model and is an inherent consequence of the underlying dynamics of this mode of ventilation. The mechanism underlying the observed instability is "feed forward" behavior mediated by oscillatory elevation in end-expiratory pressure. In both mathematical and mechanical models, unstable behavior occurred at impedance values and ventilator settings that are clinically realistic.

  11. Difficult Airway Response Team: A Novel Quality Improvement Program for Managing Hospital-Wide Airway Emergencies

    PubMed Central

    Mark, Lynette J.; Herzer, Kurt R.; Cover, Renee; Pandian, Vinciya; Bhatti, Nasir I.; Berkow, Lauren C.; Haut, Elliott R.; Hillel, Alexander T.; Miller, Christina R.; Feller-Kopman, David J.; Schiavi, Adam J.; Xie, Yanjun J.; Lim, Christine; Holzmueller, Christine; Ahmad, Mueen; Thomas, Pradeep; Flint, Paul W.; Mirski, Marek A.

    2015-01-01

    Background Difficult airway cases can quickly become emergencies, increasing the risk of life-threatening complications or death. Emergency airway management outside the operating room is particularly challenging. Methods We developed a quality improvement program—the Difficult Airway Response Team (DART)—to improve emergency airway management outside the operating room. DART was implemented by a team of anesthesiologists, otolaryngologists, trauma surgeons, emergency medicine physicians, and risk managers in 2005 at The Johns Hopkins Hospital in Baltimore, Maryland. The DART program had three core components: operations, safety, and education. The operations component focused on developing a multidisciplinary difficult airway response team, standardizing the emergency response process, and deploying difficult airway equipment carts throughout the hospital. The safety component focused on real-time monitoring of DART activations and learning from past DART events to continuously improve system-level performance. This objective entailed monitoring the paging system, reporting difficult airway events and DART activations to a web-based registry, and using in situ simulations to identify and mitigate defects in the emergency airway management process. The educational component included development of a multispecialty difficult airway curriculum encompassing case-based lectures, simulation, and team building/communication to ensure consistency of care. Educational materials were also developed for non-DART staff and patients to inform them about the needs of patients with difficult airways and ensure continuity of care with other providers after discharge. Results Between July 2008 and June 2013, DART managed 360 adult difficult airway events comprising 8% of all code activations. Predisposing patient factors included body mass index > 40, history of head and neck tumor, prior difficult intubation, cervical spine injury, airway edema, airway bleeding, and previous

  12. The critical airway in adults: The facts

    PubMed Central

    Bonanno, Fabrizio Giuseppe

    2012-01-01

    An algorithm on the indications and timing for a surgical airway in emergency as such cannot be drawn due to the multiplicity of variables and the inapplicability in the context of life-threatening critical emergency, where human brain elaborates decisions better in cluster rather than in binary fashion. In particular, in emergency or urgent scenarios, there is no clear or established consensus as to specifically who should receive a tracheostomy as a life-saving procedure; and more importantly, when. The two classical indications for emergency tracheostomy (laryngeal injury and failure to secure airway with endotracheal intubation or cricothyroidotomy) are too generic and encompass a broad spectrum of possibilities. In literature, specific indications for emergency tracheostomy are scattered and are biased, partially comprehensive, not clearly described or not homogeneously gathered. The review highlights the indications and timing for an emergency surgical airway and gives recommendations on which surgical airway method to use in critical airway. PMID:22787346

  13. Vocal Function and Upper Airway Thermoregulation in Five Different Environmental Conditions

    ERIC Educational Resources Information Center

    Sandage, Mary J.; Connor, Nadine P.; Pascoe, David D.

    2014-01-01

    Purpose: Phonation threshold pressure and perceived phonatory effort were hypothesized to increase and upper airway temperature to decrease following exposure to cold and/or dry air. Greater changes were expected with mouth versus nose breathing. Method: In a within-participant repeated measures design, 15 consented participants (7 men, 8 women)…

  14. Investigating the geometry of pig airways using computed tomography

    NASA Astrophysics Data System (ADS)

    Mansy, Hansen A.; Azad, Md Khurshidul; McMurray, Brandon; Henry, Brian; Royston, Thomas J.; Sandler, Richard H.

    2015-03-01

    Numerical modeling of sound propagation in the airways requires accurate knowledge of the airway geometry. These models are often validated using human and animal experiments. While many studies documented the geometric details of the human airways, information about the geometry of pig airways is scarcer. In addition, the morphology of animal airways can be significantly different from that of humans. The objective of this study is to measure the airway diameter, length and bifurcation angles in domestic pigs using computed tomography. After imaging the lungs of 3 pigs, segmentation software tools were used to extract the geometry of the airway lumen. The airway dimensions were then measured from the resulting 3 D models for the first 10 airway generations. Results showed that the size and morphology of the airways of different animals were similar. The measured airway dimensions were compared with those of the human airways. While the trachea diameter was found to be comparable to the adult human, the diameter, length and branching angles of other airways were noticeably different from that of humans. For example, pigs consistently had an early airway branching from the trachea that feeds the superior (top) right lung lobe proximal to the carina. This branch is absent in the human airways. These results suggested that the human geometry may not be a good approximation of the pig airways and may contribute to increasing the errors when the human airway geometric values are used in computational models of the pig chest.

  15. Intrathoracic airway measurement: ex-vivo validation

    NASA Astrophysics Data System (ADS)

    Reinhardt, Joseph M.; Raab, Stephen A.; D'Souza, Neil D.; Hoffman, Eric A.

    1997-05-01

    High-resolution x-ray CT (HRCT) provides detailed images of the lungs and bronchial tree. HRCT-based imaging and quantitation of peripheral bronchial airway geometry provides a valuable tool for assessing regional airway physiology. Such measurements have been sued to address physiological questions related to the mechanics of airway collapse in sleep apnea, the measurement of airway response to broncho-constriction agents, and to evaluate and track the progression of disease affecting the airways, such as asthma and cystic fibrosis. Significant attention has been paid to the measurements of extra- and intra-thoracic airways in 2D sections from volumetric x-ray CT. A variety of manual and semi-automatic techniques have been proposed for airway geometry measurement, including the use of standardized display window and level settings for caliper measurements, methods based on manual or semi-automatic border tracing, and more objective, quantitative approaches such as the use of the 'half-max' criteria. A recently proposed measurements technique uses a model-based deconvolution to estimate the location of the inner and outer airway walls. Validation using a plexiglass phantom indicates that the model-based method is more accurate than the half-max approach for thin-walled structures. In vivo validation of these airway measurement techniques is difficult because of the problems in identifying a reliable measurement 'gold standard.' In this paper we report on ex vivo validation of the half-max and model-based methods using an excised pig lung. The lung is sliced into thin sections of tissue and scanned using an electron beam CT scanner. Airways of interest are measured from the CT images, and also measured with using a microscope and micrometer to obtain a measurement gold standard. The result show no significant difference between the model-based measurements and the gold standard; while the half-max estimates exhibited a measurement bias and were significantly

  16. Computational fluid dynamics for the assessment of upper airway response to oral appliance treatment in obstructive sleep apnea.

    PubMed

    Zhao, Moyin; Barber, Tracie; Cistulli, Peter; Sutherland, Kate; Rosengarten, Gary

    2013-01-04

    Mandibular advancement splints (MAS), which protrude the lower jaw during sleep, are recognized as an effective treatment for obstructive sleep apnea (OSA) through their action of enlarging the airway space and preventing upper airway collapse. However a clinical challenge remains in preselecting patients who will respond to this form of therapy. We aimed to use computational fluid dynamics (CFD) in conjunction with patient upper airway scans to understand the upper airway response to treatment. Seven OSA patients were selected based on their varied treatment response (assessed by the apnea-hypopnoea index (AHI) on overnight polysomnography). Anatomically-accurate upper airway computational models were reconstructed from magnetic resonance images with and without MAS. CFD simulations of airflow were performed at the maximum flow rate during inspiration. A physical airway model of one patient was fabricated and the CFD method was validated against the pressure profile on the physical model. The CFD analysis clearly demonstrated effects of MAS treatment on the patient's UA airflow patterns. The CFD results indicated the lowest pressure often occurs close to the soft palate and the base of the tongue. Percentage change in the square root of airway pressure gradient with MAS (Δsqrt(ΔP(Max))%) was found to have the strongest relationship with treatment response (ΔAHI%) in correlation analysis (r=0.976, p=0.000167). Changes in upper airway geometry alone did not significantly correlate with treatment response. We provide further support of CFD as a potential tool for prediction of treatment outcome with MAS in OSA patients without requiring patient specific flow rates.

  17. To characterize the incidence of airway misplacement of nasogastric tubes in anesthetized intubated patients by using a manometer technique.

    PubMed

    Hsieh, Shao-Wei; Chen, Hung-Shu; Chen, Yi-Ting; Hung, Kuo-Chuan

    2017-04-01

    This study characterized the incidence of airway misplacement of nasogastric (NG) tubes in surgical patients, and the benefit of using a manometer to discriminate gastric placement from airway placement of NG tubes. Subjects included adult patients scheduled for abdominal surgery. After tracheal intubation, a 16 Fr. NG tube was inserted blindly through the nostril, and its position was assessed using the auscultation (10-ml air insufflation) or manometer (attached to NG tubes) techniques. Briefly, a biphasic pressure change synchronous with airway pressure during mechanical ventilation indicated airway misplacement. The presence of a notable pressure change while compressing the epigastric area indicated a gastric placement. A surgeon made the final confirmation of NG tube placement within the stomach using manual palpation of the tube immediately after laparotomy. The first-attempt success rate was 82.7 % in 104 patients. There were 29 misplacements of 130 attempted insertions (oral cavity, n = 23; trachea, n = 3; distal esophagus, n = 3). The incidence of airway misplacement was 2.9 % (3 of 104 cases). For confirmation of gastric placement, the auscultation technique had a sensitivity of 100.0 % and a specificity of 79.3 %. In contrast, the manometer technique had a sensitivity of 100.0 % and a specificity of 100.0 % in the discrimination of gastric placement from airway placement of NG tubes. Airway misplacement of NG tubes is not uncommon in surgical patients, and the manometer technique may be a reliable and safe method to discriminate gastric placement from airway placement of NG tubes.

  18. Glutathione redox regulates airway hyperresponsiveness and airway inflammation in mice.

    PubMed

    Koike, Yoko; Hisada, Takeshi; Utsugi, Mitsuyoshi; Ishizuka, Tamotsu; Shimizu, Yasuo; Ono, Akihiro; Murata, Yukie; Hamuro, Junji; Mori, Masatomo; Dobashi, Kunio

    2007-09-01

    Glutathione is the major intracellular redox buffer. We have shown that glutathione redox status, which is the balance between intracellular reduced (GSH) and oxidized (GSSG) glutathione, in antigen-presenting cells (APC) regulates the helper T cell type 1 (Th1)/Th2 balance due to the production of IL-12. Bronchial asthma is a typical Th2 disease. Th2 cells and Th2 cytokines are characteristic of asthma and trigger off an inflammation. Accordingly, we studied the effects of the intracellular glutathione redox status on airway hyperresponsiveness (AHR) and allergen-induced airway inflammation in a mouse model of asthma. We used gamma-Glutamylcysteinylethyl ester (gamma-GCE), which is a membrane-permeating GSH precursor, to elevate the intracellular GSH level and GSH/GSSG ratio of mice. In vitro, gamma-GCE pretreatment of human monocytic THP-1 cells elevated the GSH/GSSG ratio and enhanced IL-12(p70) production induced by LPS. In the mouse asthma model, intraperitoneal injection of gamma-GCE elevated the GSH/GSSG ratio of lung tissue and reduced AHR. gamma-GCE reduced levels of IL-4, IL-5, IL-10, and the chemokines eotaxin and RANTES (regulated on activation, normal T cell expressed and secreted) in bronchoalveolar lavage fluid, whereas it enhanced the production of IL-12 and IFN-gamma. Histologically, gamma-GCE suppressed eosinophils infiltration. Interestingly, we also found that gamma-GCE directly inhibited chemokine-induced eosinophil chemotaxis without affecting eotaxin receptor chemokine receptor 3 (CCR3) expressions. Taken together, these findings suggest that changing glutathione redox balance, increase in GSH level, and the GSH/GSSG ratio by gamma-GCE, ameliorate bronchial asthma by altering the Th1/Th2 imbalance through IL-12 production from APC and suppressing chemokine production and eosinophil migration itself.

  19. ProSeal Laryngeal Mask Airway as an Alternative to Standard Endotracheal Tube in Securing Upper Airway in the Patients Undergoing Beating-heart Coronary Artery Bypass Grafting

    PubMed Central

    Shah, Kalpana

    2017-01-01

    Background: ProSeal laryngeal mask airways (PLMAs) are routinely used after failed tracheal intubation as airway rescue, facilitating tracheal intubation by acting as a conduit and to secure airway during emergencies. In long duration surgeries, use of endotracheal tube (ETT) is associated with various hemodynamic complications, which are minimally affected during PLMA use. However, except for few studies, there are no significant data available that promote the use of laryngeal mask during cardiac surgery. This prospective study was conducted with the objective of demonstrating the advantages of PLMA over ETT in the patients undergoing beating-heart coronary artery bypass graft (CABG). Methodology: This prospective, interventional study was carried out in 200 patients who underwent beating-heart CABG. Patients were randomized in equal numbers to either ETT group or PLMA group, and various hemodynamic and respiratory parameters were observed at different time points. Results: Patients in PLMA group had mean systolic blood pressure 126.10 ± 5.31 mmHg compared to the patients of ETT group 143.75 ± 6.02 mmHg. Pulse rate in the PLMA group was less (74.52 ± 10.79 per min) (P < 0.05) compared to ETT group (81.72 ± 9.8). Thus, hemodynamic changes were significantly lower (P < 0.05) in PLMA than in ETT group. Respiratory parameters such as oxygen saturation, pressure CO2 (pCO2), peak airway pressure, and lung compliance were similar to ETT group at all evaluation times. The incidence of adverse events was also lower in PLMA group. Conclusion: In experience hand, PLMA offers advantages over the ETT in airway management in the patients undergoing beating-heart CABG. PMID:28074798

  20. Educating the Educator: Teaching Airway Adjunct Techniques in Athletic Training

    ERIC Educational Resources Information Center

    Berry, David C.; Seitz, S. Robert

    2011-01-01

    The 5th edition of the "Athletic Training Education Competencies" ("Competencies") now requires athletic training educators (ATEs) to introduce into the curriculum various types of airway adjuncts including: (1) oropharyngeal airways (OPA), (2) nasopharyngeal airways (NPA), (3) supraglottic airways (SGA), and (4) suction. The addition of these…

  1. Airway adequacy, head posture, and craniofacial morphology.

    PubMed

    Solow, B; Siersbaek-Nielsen, S; Greve, E

    1984-09-01

    Previous studies of different samples have demonstrated associations between craniocervical angulation and craniofacial morphology, between airway obstruction by adenoids and craniofacial morphology, and between airway obstruction and craniocervical angulation. A hypothesis to account for the different sets of associations was suggested by Solow and Kreiborg in 1977. In the present study, the three sets of associations were examined in a single group of nonpathologic subjects with no history of airway obstruction. Cephalometric radiographs taken in the natural head position and rhinomanometric recordings were obtained from twenty-four children 7 to 9 years of age. Correlations were calculated between twenty-seven morphologic, eight postural, and two airway variables. A large craniocervical angle was, on the average, seen in connection with small mandibular dimensions, mandibular retrognathism, and a large mandibular inclination. Obstructed nasopharyngeal airways (defined as a small pm-ad 2 radiographic distance and a large nasal respiratory resistance, NRR, determined rhinomanometrically) were, on the average, seen in connection with a large craniocervical angle and with small mandibular dimensions, mandibular retrognathism, a large mandibular inclination, and retroclination of the upper incisors. The observed correlations were in agreement with the predicted pattern of associations between craniofacial morphology, craniocervical angulation, and airway resistance, thus suggesting the simultaneous presence of such associations in the sample of nonpathologic subjects with no history of airway obstruction.

  2. Comparison of analysis methods for airway quantification

    NASA Astrophysics Data System (ADS)

    Odry, Benjamin L.; Kiraly, Atilla P.; Novak, Carol L.; Naidich, David P.

    2012-03-01

    Diseased airways have been known for several years as a possible contributing factor to airflow limitation in Chronic Obstructive Pulmonary Diseases (COPD). Quantification of disease severity through the evaluation of airway dimensions - wall thickness and lumen diameter - has gained increased attention, thanks to the availability of multi-slice computed tomography (CT). Novel approaches have focused on automated methods of measurement as a faster and more objective means that the visual assessment routinely employed in the clinic. Since the Full-Width Half-Maximum (FWHM) method of airway measurement was introduced two decades ago [1], several new techniques for quantifying airways have been detailed in the literature, but no approach has truly become a standard for such analysis. Our own research group has presented two alternative approaches for determining airway dimensions, one involving a minimum path and the other active contours [2, 3]. With an increasing number of techniques dedicated to the same goal, we decided to take a step back and analyze the differences of these methods. We consequently put to the test our two methods of analysis and the FWHM approach. We first measured a set of 5 airways from a phantom of known dimensions. Then we compared measurements from the three methods to those of two independent readers, performed on 35 airways in 5 patients. We elaborate on the differences of each approach and suggest conclusions on which could be defined as the best one.

  3. Physiological Effects of Positive Pressure Ventilation.

    DTIC Science & Technology

    1992-05-01

    spontaneous breath (Banner, et al., 1990). This "stacking" of mechanical on spontaneous breaths could increase the peak inflation, airway , and intrapleural...J., & Gottfried, S. B. (1990). Continuous positive airway pressure reduces work of breathing and dyspnea during weaning from mechanical ventilation in...insufficiency is caused by numerous physiological aberrations, some of which can be reversed or improved by mechanical respiratory support, thus

  4. Store-operated Ca2+ channels in airway epithelial cell function and implications for asthma

    PubMed Central

    Samanta, Krishna; Parekh, Anant B.

    2016-01-01

    The epithelial cells of the lung are at the interface of a host and its environment and are therefore directly exposed to the inhaled air-borne particles. Rather than serving as a simple physical barrier, airway epithelia detect allergens and other irritants and then help organize the subsequent immune response through release of a plethora of secreted signals. Many of these signals are generated in response to opening of store-operated Ca2+ channels in the plasma membrane. In this review, we describe the properties of airway store-operated channels and their role in regulating airway epithelial cell function. This article is part of the themed issue ‘Evolution brings Ca2+ and ATP together to control life and death’. PMID:27377718

  5. Airway smooth muscle growth in asthma: proliferation, hypertrophy, and migration.

    PubMed

    Bentley, J Kelley; Hershenson, Marc B

    2008-01-01

    Increased airway smooth muscle mass is present in fatal and non-fatal asthma. However, little information is available regarding the cellular mechanism (i.e., hyperplasia vs. hypertrophy). Even less information exists regarding the functional consequences of airway smooth muscle remodeling. It would appear that increased airway smooth muscle mass would tend to increase airway narrowing and airflow obstruction. However, the precise effects of increased airway smooth muscle mass on airway narrowing are not known. This review will consider the evidence for airway smooth muscle cell proliferation and hypertrophy in asthma, potential functional effects, and biochemical mechanisms.

  6. Myeloid sarcoma causing airway obstruction

    PubMed Central

    Krause, John R.

    2017-01-01

    Myeloid sarcoma is an extramedullary collection of blasts of the myeloid series that partially or totally effaces the architecture of the tissue in which it is found. These tumors have been described in many sites of the body, but the skin, lymph nodes, gastrointestinal tract, bone, soft tissue, and testes are most common. They can arise in a patient following the diagnosis of acute myeloid leukemia, but they may also be precursors of leukemia and should be considered diagnostic for acute myeloid leukemia. The differential diagnosis of this neoplasm includes malignant lymphoma, with which it is often mistaken, leading to diagnostic and therapeutic delays. We present the case of an 84-year-old African American man with a history of renal disease secondary to hypertension and coronary artery disease without any prior history of malignancies who presented with airway obstruction. He was diagnosed with a myeloid sarcoma of the mediastinum compressing his trachea.

  7. The Development and Application of Airway Devices in China

    PubMed Central

    Chen, Xiangdong; Ma, Wuhua; Liu, Renyu; Yao, Shanglong

    2017-01-01

    Airway management is one of the most important tasks for anesthesiologists. Anesthesiologists are experts in airway management and have made tremendous contribution to the development of the airway devices. Chinese anesthesiologists have made significant contribution in introducing advanced airway management and developing innovative techniques and devices for airway management in China. This article overviews the development and application of airway devices in China as well as the dedication and contribution of Chinese experts in the development of novel airway devices. With the development of science and technology accompanied by the advanced knowledge in airway management, more effective and safe artificial airways will be developed for clinical practice. The authors believe that Chinese experts will continue their outstanding contribution to the development of innovative airway devices, systems and knowledge. PMID:28191485

  8. Pharmacology of airway afferent nerve activity

    PubMed Central

    Undem, Bradley J; Carr, Michael J

    2001-01-01

    Afferent nerves in the airways serve to regulate breathing pattern, cough, and airway autonomic neural tone. Pharmacologic agents that influence afferent nerve activity can be subclassified into compounds that modulate activity by indirect means (e.g. bronchial smooth muscle spasmogens) and those that act directly on the nerves. Directly acting agents affect afferent nerve activity by interacting with various ion channels and receptors within the membrane of the afferent terminals. Whether by direct or indirect means, most compounds that enter the airspace will modify afferent nerve activity, and through this action alter airway physiology. PMID:11686889

  9. On locating the obstruction in the upper airway via numerical simulation

    PubMed Central

    Wang, Yong; Elghobashi, S.

    2014-01-01

    The fluid dynamical properties of the air flow in the upper airway (UA) are not fully understood at present due to the three-dimensional (3D) patient-specific complex geometry of the airway, flow transition from laminar to turbulent and flow-structure interaction during the breathing cycle. It is quite difficult at present to experimentally measure the instantaneous velocity and pressure at specific points in the human airway. On the other hand, direct numerical simulation (DNS) can predict all the flow properties