Continuous Positive Airway Pressure Requirement Research Articles

Correlation between Neck Circumference and Continuous Positive Airway Pressure among Patients of Obstructive Sleep Apnea

Objective: To investigate the relationship between neck circumference (NC) and continuous positive airway pressure (CPAP) in patients with obstructive sleep apnea (OSA), as well as to assess CPAP requirements based on the neck circumference. Material and methods: This study was carried out in the pulmonary, vascular, and sleep disorders department of the Dow University Hospital in Karachi. The study was done for six months of duration from January 2022 to June 2022. All of the patients who had obstructive sleep apnea (OSA), between the ages of 18 and 60 years, both genders and underwent CPAP therapy were chosen for this study. The polysomnography database was utilized in order to do an analysis on the Apnea-Hypopnea Index for the OSA. Neck circumference was measured at the neck’s middle sit in every participant. The neck circumference was correlated with the CPAP therapy. The structured study proforma was used to collect all the data. Results: A total of 181 individuals who presented with OSA were studied. Mean age of the cases were 52.86+12.26 years and mean neck circumference was 43.45+3.58 cm. Males were 58.0% and females were 42.0%. Majority of the cases 56.4% had severe OSA. There was a strong significant positive correlation between neck circumference and CPAP (r= 0.177, p-value 0.017) and significant positive correlation between neck circumference and CPAP (r= 0.366, p-value 0.001). Average of CPAP pressure was significantly high according to severity of OSA (p-0.0001). Conclusion: The neck circumference was observed to be the most reliable marker that significantly positively correlated with CPAP therapy and measurements of OSA and its severity, by AHI alone, seem to have a positive correlation with CPAP therapy. However, OSA evaluation and treatment can be measured for their responsiveness to CPAP based on their neck circumference. Keywords: OSA, NC, CPAP, Relationship

Impact of SARS-CoV-2 on incidence, treatment and outcome of very preterm born infants in Switzerland: a retrospective, population-based cohort study.

To assess whether the COVID-19 pandemic caused by SARS-CoV-2 had an impact on incidence, treatment or major adverse short-term outcome of preterm-born infants in Switzerland. Retrospective cohort study of preterm infants born in 2020 based on two independent data sources from the Swiss Federal Statistics Office (FSO) and SwissNeoNet. Based on FSO data, we calculated the odds ratios for extremely preterm (22-27 weeks gestation), very preterm (28-31 weeks gestation), and late preterm (32-36 weeks gestation) births during the pandemic. Based on SwissNeoNet data of infants born between 22 and 31 weeks gestation, we compared infants born during the Swiss lockdown period in 2020 with infants born during the same period between 2015 and 2019, all infants of 2020 with all infants between 2015 and 2019 and infants born to mothers tested SARS-CoV-2 positive and negative. Possible associations with the pandemic were tested using logistic regression adjusted for case-mix. As a control, we compared births of 2019 with those of 2015-2018. The FSO data revealed equivalent odds for extremely preterm births in 2020 (odds ratio [OR] 1.01, 95% confidence interval [CI] 0.89-1.14), as well as somewhat lower odds ratios for very preterm (OR 0.9, 95% CI 0.82-1.00) and late preterm (OR 0.91, 95% CI 0.88-0.93) births in 2020. A comparison between 2019 and 2015-2018, however, revealed matching odds ratios rendering an association to the pandemic unlikely. In the SwissNeoNet data, 137 infants were born during lockdown in 2020 compared with 134 births per year during 2015-2019. When including all infants, 744 infants were compared to 845 births, respectively. The only difference observed in treatments and short term outcomes between 2020 and the reference years were a higher odds for respiratory distress syndrome (OR 1.6, 95% CI 1.08-2.37) and provision of continuous positive airway pressure (CPAP) (OR 1.39, 95% CI 1.05-1.84). Our Swiss population-based analysis did not identify the elsewhere reported association between the COVID-19 pandemic and a reduced preterm birth rate. However, we can confirm a possible link between the COVID-19 pandemic and higher odds of respiratory distress syndrome, possibly coupled with CPAP requirements. Further observation of potential effects of the pandemic on health and health care provision to newborns may however be indicated based on the literature available so far and that our data only covers the first 9 months of the current pandemic.

Science, Medicine, and the Anesthesiologist

Science, Medicine, and the Anesthesiologist

Titration studies overestimate continuous positive airway pressure requirements in uncomplicated obstructive sleep apnea.

Attended manual continuous positive airway pressure (CPAP) titration is the standard practice for determining optimal positive airway pressures for obstructive sleep apnea (OSA) treatment. However, an unattended single night auto-titrating positive airway pressure (APAP) titration is an alternative. The goal of this study was to determine whether therapeutic CPAP pressures determined during manual titrations are higher than APAP-generated surrogate pressures. We conducted a retrospective review of 165 adults with uncomplicated OSA who had full/split-night manual CPAP titrations prior to commencing treatment with APAP. Demographic and clinical data including 30-day APAP compliance data were obtained. We compared the recommended CPAP pressure from manual titrations with the 90th/95th percentile pressure generated from APAP usage over 30 days. The recommended CPAP pressures during the manual titrations were higher than the 90th/95th percentile pressures generated from APAP (11.4 ± 3.4 vs 10.3 ± 2.4 cmH2O; P = .000). Almost half the group (41.9%) had their manually derived titration pressure at least 1.5 cm above the 90th/95th percentile pressure. In multivariate analyses, body mass index was the only variable that predicted higher manual titration pressures. Notably, the average residual apnea-hypopnea index on 30-day APAP data was less than the average residual apnea-hypopnea index observed at the recommended pressure during the manual titration (5.0 ± 4.3 vs 7.2 ± 8.5; P = .006). Manual CPAP titrations may overestimate pressure requirements, particularly in patients with higher body mass index, and may not be necessary in managing patients with uncomplicated OSA. APAP appears to be at least as effective as single-pressure CPAP, while delivering lower positive airway pressure. Fashanu OS, Budhiraja R, Batool-Anwar S, Quan SF. Titration studies overestimate continuous positive airway pressure requirements in uncomplicated obstructive sleep apnea. J Clin Sleep Med. 2021;17(9):1859-1863.

Are there sex-related differences in therapeutic CPAP levels in adults undergoing in-laboratory titration?

The first-choice therapy for adults with moderate/severe obstructive sleep apnea is continuous positive airway pressure (CPAP). However, studies evaluating whether the therapeutic CPAP level obtained from a titration is affected by sex are surprisingly scarce. Our main objective was to verify if sex influenced the optimal CPAP measurement obtained during a titration. This cross-sectional study was conducted in adults diagnosed with moderate/severe obstructive sleep apnea [baseline apnea-hypopnea index (AHI) ≥ 15.0 events/h] who underwent auto-adjusting CPAP titration (S9 or S10 AutoSet ResMed) in a sleep laboratory setting. All participants used a nasal mask during the titration. The optimal pressure, leak, and residual AHI values were registered. Multiple linear regression was used to evaluate if clinical and polysomnographic data influenced the therapeutic CPAP level setting (95th percentile pressure). A total of 1,006 adults were enrolled: 354 women and 652 men. There were no statistically significant sex-related differences in the CPAP requirements and leak values delineated during the titration; all P-values > .005. However, the median residual AHI was significantly higher in males vs females: 2.7 events/h vs 2.2 events/h (P = .008). Body mass index (β: 0.292, P < .001), baseline AHI (β: 0.167, P < .001), and age (β: 0.065, P = .035) were independent predictors of the therapeutic CPAP level settings. Sex does not significantly influence the therapeutic CPAP settings. However, age, BMI, and baseline AHI emerge as independent predictors of the 95thpercentile CPAP requirement during an auto-adjusting CPAP titration. Duarte RLM, Magalhães-da-Silveira FJ, Gozal D. Are there sex-related differences in therapeutic CPAP levels in adults undergoing in-laboratory titration? JClin Sleep Med. 2021;17(9):1815-1820.

Diaphragmatic thickening fraction as a potential predictor of response to continuous positive airway pressure ventilation in Covid-19 pneumonia: A single-center pilot study

BackgroundIn a variable number of Covid-19 patients with acute respiratory failure, non-invasive breathing support strategies cannot provide adequate oxygenation, thus making invasive mechanical ventilation necessary. Factors predicting this unfavorable outcome are unknown, but we hypothesized that diaphragmatic weakness may contribute. MethodsWe prospectively analyzed the data of 27 consecutive patients admitted to the general Intensive Care Unit (ICU) from March 19, 2020, to April 20, 2020 and submitted to continuous positive airway pressure (CPAP) before considering invasive ventilation. Diaphragmatic thickening fraction (DTF) inferred by ultrasound was determined before applying CPAP. ResultsEighteen patients recovered with CPAP, whereas nine required invasive mechanical ventilation with longer stay in ICU (p < 0.001) and hospital (p = 0.003). At univariate logistic regression analysis, CPAP failure was significantly associated with low DTF [β: -0.396; OR: 0.673; p < 0.001] and high respiratory rate [β: 0.452; OR: 1.572; p < 0.001] but only DTF reached statistical significance at multivariate analysis [β: -0.384; OR: 0.681; p < 0.001]. The DTF best threshold predicting CPAP failure was 21.4 % (AUC: 0.944; sensitivity: 94.4 %, specificity: 88.9 %). ConclusionsIn critically ill patients with Covid-19 respiratory failure admitted to ICU, a reduced DTF could be a potential predictor of CPAP failure and requirement of invasive ventilation.

Effects of bariatric surgery on indices of obstructive sleep apnoea and pulmonary function tests

Background: Obesity reaches the epidemic situation. Obstructive sleep apnoea is a major concern in obese patients. Aim of the work:To analyse apnoea hypopnea index and to evaluate changes in pulmonary functions before and after bariatric surgery in obese patients.Patients and Methods: We identify 160 patients who met our inclusion criteria. However, 121 patients returned for follow up evaluation. They were 98 women and 23 men. 84 had Raux-en-Y gastric bypass and 37 had sleeve gastrectomy. They were subjected to full history taking, clinical examination, objective measures of obstructive sleep apnoea [apnoea hypopnea index, body mass index, mean oxygen saturation, low oxygen saturation, nasal continuous positive airway pressure and Pulmonary function tests]. In addition, all patients were submitted to a sleep study.Results:Statistically significant improvement was obtained postoperative for apnoea hypopnea index, body mass index, nasal continuous positive airway pressure requirement, mean oxygen saturation and low oxygen saturation. The spirometry and lung volume finding showed statistically significant improvement in lung function parameters after surgery. There was a significant positive correlation between body mass index and apnoea hypopnea index, with significant negative correlation between body mass index and forced vital capacity.Conclusion: Bariatric surgery is associated with significant improvement in pulmonary functions and obstructive sleep apnoea indices

Dose-dependent effects of mandibular advancement on optimal positive airway pressure requirements in obstructive sleep apnoea.

Implementation of mandibular advancement splint (MAS) therapy as first-line treatment for obstructive sleep apnoea (OSA) is hindered by inter-individual variability of treatment outcomes and lack of robust patient selection methods. Optimal continuous positive airway pressure (CPAP) requirement provides an estimate of airway collapsibility severity, and high CPAP requirements predict MAS therapy failure in retrospective studies. Thus, understanding the effects of mandibular advancement on optimal CPAP requirements may enhance optimisation of patient selection for MAS therapy. This study aims to determine dose-dependent effects of mandibular advancement on optimal CPAP requirements in OSA. Prior to MAS therapy initiation, participants with OSA (apnoea-hypopnea index (AHI) > 10 events/h) underwent a research polysomnogram in which a remotely controlled mandibular positioner (RCMP) was used to determine dose-response effects of varying mandibular advancement positions (0% 'habitual bite' and 25, 50, 75 and 100% of maximum mandibular advancement, in random order) on optimal CPAP requirements. A separate polysomnography determined treatment outcome. Data are presented as mean ± SD or median (1st-3rd quartiles). Seventeen participants (age = 47 ± 9years, body mass index = 26kg/m2 (23-27), apnoea-hypopnea index = 18 events/h (14-44) and minimal oxygen saturation = 84 ± 7%) were studied. Optimal CPAP requirements were reduced with mandibular advancement in a dose-dependent manner (8.9 ± 2.4 vs. 7.9 ± 2.8, 6.4 ± 1.8, 5.7 ± 1.9 and 4.9 ± 1.8cmH2O; respectively, p < 0.0001). Compared with non-responders, responders to MAS therapy had lower AHI, lower arousal index and greater MinSaO2 at baseline. Optimal CPAP requirements at 0% mandibular advancement (or other positions) were not different between groups. Increasing mandibular advancement lowers optimal CPAP requirements in a dose-dependent manner. This supports prior work indicating a beneficial effect of MAS on upper airway collapsibility.

A randomised crossover trial comparing nasal masks with oronasal masks: No differences in therapeutic pressures or residual apnea-hypopnea indices.

In treating obstructive sleep apnea (OSA), the use of oronasal masks with continuous positive airway pressure (CPAP) has been reported to increase pressure levels and reduce compliance. These reports come mostly from large observational studies. In this study, we examined the impact that oronasal masks have on 95th centile pressures, the residual apnea-hypopnea index (AHI) and compliance compared with nasal masks. A randomised crossover design was implemented. Participants already established on CPAP were randomly allocated to a nasal mask or oronasal mask with auto-titrating positive airway pressure (APAP) for 2weeks. Participants then crossed over to use the alternate mask for another 2weeks. Seventy-one participants were recruited but only 60 completed the trial. There were no differences in median 95th centile pressure (nasal, 11.5cm H2 O; oronasal, 11.7cm H2 O; p=0.115), median residual AHI (nasal, 4.9 events/hr; oronasal, 5.3 events/hr; p=0.234) or median compliance (nasal, 7.3hr/night; oronasal, 7.3hr/night; p=0.961). Only four patients had 95th centile pressures that were at least 1.5cm H2 O greater with oronasal masks. Oronasal masks do not systematically increase therapeutic CPAP requirements. Rather, a small subset of patients display significant differences in CPAP levels.

Impact of bariatric surgery on obstructive sleep apnoea-hypopnea syndrome in morbidly obese patients.

Background:Obstructive sleep apnea (OSA) is commonly associated with morbid obesity. Weight loss following bariatric surgery results in resolution or improvement of OSA. However, few studies have done objective assessment of the impact of bariatric surgery on OSA.Objective:The aim of this study was to assess the outcome of bariatric surgery on OSA.Setting:The study was conducted in the teaching institution of a tertiary care centre.Methods:Twenty-seven morbidly obese patients seeking bariatric surgery were administered Epworth Sleepiness Scale (ESS) health questionnaire and subjected to overnight polysomnography. Repeat assessment using ESS and polysomnography was done at 3–6 months after surgery.Results:Mean age was 42.4 ± 10.5 years, and majority (77.8%) were female. The mean pre-operative weight and body mass index (BMI) were 126.4 ± 24.9 kg and 48.4 ± 8.2 kg/m2, respectively. Nearly 29.6% patients had symptoms of excessive daytime somnolence based on ESS score and overnight polysomnography detected the presence of OSA in 96.3% patients, of which 51.9% had severe OSA. At mean follow-up of 5.2 ± 2.5 months after surgery, mean weight and BMI decreased to 107.4 ± 24.5 kg and 41.2 ± 8.2 kg/m2, respectively. Mean ESS score and mean apnoea–hypopnea index declined from 8.9 ± 3.2 to 4.03 ± 2.15 (P < 0.001) and from 31.8 ± 20.4 to 20.2 ± 23.1 (P = 0.007), respectively. Number of patients requiring continuous positive airway pressure (CPAP) therapy declined from 15 to 3 and average CPAP requirement came down from 11.3 cm of H2O to 6 cm of H2O.Conclusion:OSA was present in a significant proportion of patients undergoing bariatric surgery. Bariatric surgery resulted in significant improvement in both subjective and objective parameters of OSA.

Oronasal Masks Require a Higher Pressure than Nasal and Nasal Pillow Masks for the Treatment of Obstructive Sleep Apnea.

Oronasal masks are frequently used for continuous positive airway pressure (CPAP) treatment in patients with obstructive sleep apnea (OSA). The aim of this study was to (1) determine if CPAP requirements are higher for oronasal masks compared to nasal mask interfaces and (2) assess whether polysomnography and patient characteristics differed among mask preference groups. Retrospective analysis of all CPAP implementation polysomnograms between July 2013 and June 2014. Prescribed CPAP level, polysomnography results and patient data were compared according to mask type (n = 358). Oronasal masks were used in 46%, nasal masks in 35% and nasal pillow masks in 19%. There was no difference according to mask type for baseline apnea-hypopnea index (AHI), body mass index (BMI), waist or neck circumference. CPAP level was higher for oronasal masks, 12 (10-15.5) cm H2O compared to nasal pillow masks, 11 (8-12.5) cm H2O and nasal masks, 10 (8-12) cm H2O, p < 0.0001 (Median [interquartile range]). Oronasal mask type, AHI, age, and BMI were independent predictors of a higher CPAP pressure (p < 0.0005, adjusted R(2) = 0.26.). For patients with CPAP ≥ 15 cm H2O, there was an odds ratio of 4.5 (95% CI 2.5-8.0) for having an oronasal compared to a nasal or nasal pillow mask. Residual median AHI was higher for oronasal masks (11.3 events/h) than for nasal masks (6.4 events/h) and nasal pillows (6.7 events/h), p < 0.001. Compared to nasal mask types, oronasal masks are associated with higher CPAP pressures (particularly pressures ≥ 15 cm H2O) and a higher residual AHI. Further evaluation with a randomized control trial is required to definitively establish the effect of mask type on pressure requirements. A commentary on this article appears in this issue on page 1209.

Levels of ischemia-modified albumin in transient tachypnea of the newborn.

The aim of the article is to evaluate ischemia-modified albumin (IMA) levels in infants with transient tachypnea of the newborn (TTN) and to find out its relation to the disease severity. Patients and Infants with > 37 weeks of gestation, without any respiratory and cardiac symptoms and without any maternal health problems, and diagnosed as TTN were allocated as the study group. Patients with obvious retractions, grunting, hypercarbia (Pco 2 > 60 mm Hg) or hypoxia (oxygen saturation < 88% with Fio 2 of 0.60) were managed with nasal continuous positive airway pressure (CPAP). During the postnatal 0 to 24 hours, blood samples were collected in 2 mL for IMA. A total of 47 patients were diagnosed TTN, and allocated as the study group. Of the 47 patients, 43 patients without respiratory symptoms were enrolled as the control group. IMA levels in TTN were found to be significantly higher (p < 0.05). In addition, IMA levels were significantly increased in the nasal CPAP group versus supplemental oxygen therapy groups (p < 0.05). IMA levels were determined to be significantly higher in the > 3 days of oxygen therapy group (p < 0.05). IMA levels with a cutoff point of 0.87 ABSU, sensitivity of 81.1% and specificity of 69.8% predicted TTN (area under the curve [AUC] = 0.85; p < 0.05). IMA levels with > 0.98 ABSU, 78% sensitivity, and 86% specificity indicated the prediction of CPAP requirement (AUC = 0.86; p < 0.05). IMA levels were significantly higher in infants with diagnosed TTN. Therefore, IMA may be used as a new marker for predicting TTN and disease severity.

Neonatal respiratory consequences from water birth in a tertiary centre

9 April 2012 We read with great interest the recent study by Carpenter and Weston,1 who evaluated the differentiating features for respiratory distress after water birth versus air birth in term low-risk neonates. Clinical and X-ray features were assessed to determine if the disease process could be differentiated. The authors reported that the water birth babies showed greater acidosis and greater requirement for ventilation and nitric oxide treatment. They stated that the morbidity in water birth group may be attributable to water aspiration and likely to be avoidable if delivery into water is not chosen. In a recent study, we sought to investigate the demographic and clinical features, birth complications, infection rates and rates of neonatal intensive care unit attendance of 191 water birth infants in a 5-year period.2 The mean gestational age and birthweight of the patients were 39.2 ± 1.3 weeks and 3326 ± 409 g, respectively. Four of the patients (2%) were admitted to the neonatal intensive care unit because of respiratory distress soon after birth. Three patients required continuous positive airway pressure (CPAP), and one required supplemental oxygen. We did not observe low Apgar scores, low pH, unexplained deaths, drowning, hyponatraemia due to water intoxication, water aspiration leading to respiratory distress syndrome and respiratory failure. None of the patients required mechanical ventilation or inhaled nitric oxide for pulmonary hypertension. Meconium aspiration was not present in any patient. The chest X-rays of three patients were compatible with transient tachypnoea of newborn and one with pneumonia. Except for the patient who received antibiotic therapy because of neonatal pneumonia, infection screening tests were negative for the other three patients. CPAP requirement lasted for 1 day in three patients, but for 2 days in the patient diagnosed with congenital pneumonia. All other newborns were evaluated as healthy, observed beside their mother for 1 day and breastfed. In conclusion, our report demonstrated that water birth is a safe, valuable and promising alternative method of delivery for the neonates when certain criteria are met, and its effect on neonatal outcomes, particularly related to respiratory complications, seems to be acceptable.

Clinical predictors of nasal continuous positive airway pressure requirement in acute bronchiolitis

Clinical predictors of nasal continuous positive airway pressure requirement in acute bronchiolitis

Continuous positive airway pressure requirements in patients with tetraplegia and obstructive sleep apnoea

Clinic-based retrospective case-control study. To compare continuous positive airway pressure (CPAP) requirements between patients with tetraplegia and able-bodied patients with obstructive sleep apnoea (OSA). Melbourne, Australia. Diagnostic and CPAP titration polysomnograms of 219 able-bodied, and 25 patients with tetraplegia and OSA were compared for apnoea hypopnoea index (AHI) and CPAP levels required to effectively treat OSA. Demographics and body mass index (BMI) were obtained for each patient. ASIA score and injury date were obtained for patients with tetraplegia. There was no significant difference in AHI (P=0.102) between the two groups; however, able-bodied patients were significantly older (P=0.003), required significantly higher levels of CPAP to control their OSA (P<0.001) and had higher BMIs (P=0.009) than patients with tetraplegia. In the tetraplegia group, there was no significant correlation between AHI and effective CPAP (r=0.022, P=0.92) or between AHI and BMI (r=-0.196, P=0.35). There was a significant correlation between effective CPAP and BMI (r=0.411, P=0.041). Among able-bodied patients, over two-thirds (68.8%) required 10-16 cm H(2)0 to control their OSA and nearly one-third required over 16 cm H(2)0. In contrast, over two-thirds (68.8%) in the tetraplegia group required less than 10 cm H(2)0 of CPAP to control their OSA. This retrospective study suggests that OSA patients with tetraplegia require significantly less CPAP to treat their OSA at any given AHI than those who are able-bodied. This suggests that additional unknown factors may contribute to the high prevalence of OSA in tetraplegia.

Clinical predictors of nasal continuous positive airway pressure requirement in acute bronchiolitis

There is growing use of nasal continuous positive airway pressure ventilation (nCPAP) for infants with bronchiolitis, based on clinical assessment of severity. Despite this there have been no studies which identify clinical predictors for the requirement of nCPAP. To identify clinical factors in infants with acute bronchiolitis in the emergency department (ED), which might predict a requirement for nCPAP following admission. Retrospective review of pediatric ED case notes was conducted on bronchiolitis admissions to one dedicated Paediatric ED over a 12-month period. Potential predictors were identified through literature review. Data extraction of predictors was carried out and recorded for each case. Logistic regression was conducted for each variable to identify statistically significant predictors of nCPAP requirement. Twenty-eight (17%) of the 163 admitted infants received nCPAP. The strongest predictors of nCPAP requirement in were as follows: oxygen requirement within the ED (P < 0.001), lower oxygen saturation (P < 0.001), younger age at presentation (P = 0.002), higher respiratory rate (P = 0.002), higher heart rate (P = 0.003), lower Glasgow Coma Scale score (0.006), and younger gestational age (P = 0.024). We have identified clinical variables that were predictive of nCPAP requirement in infants admitted to our unit with bronchiolitis, oxygen requirement in the ED being the strongest single predictor. This is the first such study in the UK, and we hope it may be a starting point for further work that may provide an evidence base to aid clinicians in predicting the use of nCPAP in infants with bronchiolitis.

Influence of gender on continuous positive airway pressure requirements in patients with obstructive sleep apnea syndrome

Gender differences have been noted in key aspects of upper airway physiology and pathophysiology of obstructive sleep apnea (OSA). We postulate that these will lead to disparities in pharyngeal collapsibility and, consequently, positive airway pressure requirements of patients with OSA. A retrospective review of 95 adult patients (56 women, 39 men) with OSA was done. Patients who underwent continuous positive airway pressure (CPAP) titration were included in the study. The study groups were similar with regard to the severity of OSA (median apnea-hypopnea index of 34 in men and 24 in women, p = 0.13). The men were older and less obese than the women (mean age of 46 and 41 years, p = 0.03, BMI of 42 and 49 kg/m(2), p < 0.001, in men and women, respectively); Epworth score was similar in the two groups (12 vs.11, p = 0.91). CPAP requirement was higher in men than in women (12.7 vs. 10.2, p < 0.0001). The effect of gender on CPAP requirement was found to be significant even when confounding variables were accounted for using linear regression. Men with OSA are more likely to require higher levels of CPAP support than women. The effect of gender on CPAP requirement persisted even after correcting for the severity of OSA.

P75 Clinical predictors of continuous positive airway pressure requirement in bronchiolitis

BackgroundBronchiolitis is the commonest respiratory viral illness in infants with the potential for significant morbidity. There is growing evidence for the use of continuous positive airway pressure (CPAP) non-invasive ventilation...

Lung volume and pharyngeal stability in sleeping humans: the knee bone is connected to the thigh bone

in 1988 the Journal of Applied Physiology published a seminal article by William Van de Graaff ([13][1]) demonstrating that inflation of the thorax in anesthetized dogs decreased upper airway resistance independently of upper airway muscle activity. The mechanism underlying this effect was shown to

Obstructive Sleep Apnoea (OSA) Patterns in Bariatric Surgical Practice and Response of OSA to Weight Loss after Laparoscopic Adjustable Gastric Banding (LAGB)

This study aims to evaluate the incidence of Obstructive Sleep Apnoea (OSA) in severely obese Asians and to study the impact of weight loss on OSA. We report the results of routine preoperative Polysomnograms in 350 Asian patients undergoing bariatric surgery in our institute. Polysomnograms were repeated in 75 randomly selected patients with moderate to severe OSA after target weight loss with the laparoscopically placed adjustable gastric band (LAGB). The prevalence of OSA in obese Asians is high. Moderate OSA was found in 46% of patients and severe OSA was found in 33%. Severe OSA was significantly more in the Chinese (46%) compared to the Malays (29%) or Indians (21%) (P = 0.035). We identified other risk factors for severe OSA (male sex, higher body mass index and the presence of hypertension) but were unable to select identifying parameters for very low (<5%) likelihood of severe OSA such that routine sleep studies prior to bariatric surgery could be omitted. Apnoea Hypoapnoea Index (AHI) showed improvement of 50% at 20 kg excess weight loss with the cure of OSA in preoperatively severe cases (P <0.005). Mild to moderate cases reported similar improvements although a direct correlation could not be established. Desaturation events, apnoea episodes, work of breathing and subjective assessment of sleepiness scores and quality of life (QOL) showed improving trends, albeit not statistically significant. Similar improvements were seen in sleep architecture with increased rapid eye movement (REM) and stage 3 sleep. The incidence of OSA in Asians undergoing bariatric surgery is high. Routine sleep studies in Asian patients are justified. Weight loss brought about a significant improvement in AHI and continuous positive airway pressure requirements. LAGB placement should be considered a broadly effective therapy for sleep apnoea in the severely obese patient.