Rationale: Obesity increases the risk and severity of sleep-disordered breathing. The degree to which excess body weight contributes to blood oxygen desaturation during hypopneic and apneic events has not been comprehensively characterized. Objectives: To quantify the association between excess body weight and oxygen desaturation during sleep-disordered breathing. Methods: A total of 750 adult participants in the Wisconsin Sleep Cohort Study were assessed for body mass index (BMI) (kg/m 2 ) and sleep-disordered breathing. The amount of Sa O 2 , duration, and other characteristics of 37,473 observed breathing events were measured during polysomnography studies. A mixed-effects linear regression model estimated the association of blood oxygen desaturation with participant-level characteristics, including BMI, gender, and age, and event-level characteristics, including baseline Sa O 2 , change in VT, event duration, sleep state, and body position. Measurements and Main Results: BMI was positively associated with oxygen desaturation severity independent of age, gender, sleeping position, baseline Sa O 2 , and event duration. BMI interacted with sleep state such that BMI predicted greater desaturation in rapid eye movement (REM) sleep than in non-REM sleep. Each increment of 10 kg/m 2 BMI predicted a 1.0% (SE, 0.2%) greater mean blood oxygen desaturation for persons in REM sleep experiencing hypopnea events associated with 80% VT reductions. Conclusions: Excess body weight is an important predictor of the severity of blood oxygen desaturation during apnea and hypopnea events, potentially exacerbating the impact of sleep-disordered breathing in obese patients.Keywords: sleep apnea; overweight; hypoxia Obesity is one of the most important risk factors for sleepdisordered breathing (SDB) (1). Epidemiological studies have shown that the prevalence of SDB is strongly associated with excess body weight (2) and that weight gain independently predicts the development of SDB (3). Moreover, most (4), but not all (5), interventional studies have shown that weight loss is effective in reducing apneas and hypopneas. As the prevalence of obesity increases across industrialized nations, it is predicted that obesity will cause a corresponding increase in the prevalence of SDB (1, 6).The frequency of apneas and hypopneas increases with obesity (3, 7). The frequency of breathing events is an important predictor of the consequences of SDB, with a longitudinal doseresponse relationship between the apnea-hypopnea index (AHI) and the prevalence of cardiovascular morbidity (8). The severity of oxygen desaturation during obstructive breathing events and the cumulative burden of nocturnal hypoxia are important factors in this relationship; they also predict cardiovascular morbidity in patients with SDB, independent of the frequency of breathing events (9, 10). Because excess body weight is known to predispose to more severe oxygen desaturation during voluntary apneas (11), obese patients with SDB may be disadvantaged by greater oxygen desatu...

BackgroundOver 30% of adult patients with pleural infection either die and/or require surgery. There is no robust means of predicting at baseline presentation which patients will suffer a poor clinical outcome. A validated risk prediction score would allow early identification of high-risk patients, potentially directing more aggressive treatment thereafter.ObjectivesTo prospectively assess a previously described risk score (RAPID - Renal (urea), Age, fluid Purulence, Infection source, Dietary (albumin)) in adults with pleural infection.MethodsProspective observational cohort study recruiting patients undergoing treatment for pleural infection. RAPID score and risk category were calculated at baseline presentation. The primary outcome was mortality at 3 months; secondary outcomes were mortality at 12 months, length of hospital stay, need for thoracic surgery, failure of medical treatment, and lung function at 3 months.ResultsMortality data were available in 542 of 546 (99.3%) patients recruited. Overall mortality was 10% (54/542) at 3 months and 19% (102/542) at 12 months. The RAPID risk category predicted mortality at 3 months; low-risk (RAPID score 0–2) mortality 5/222 (2.3%, 95%CI 0.9 to 5.7), medium-risk (RAPID score 3–4) mortality 21/228 (9.2%, 95%CI 6.0 to 13.7), and high-risk (RAPID score 5–7) mortality 27/92 (29.3%, 95%CI 21.0 to 39.2). C-statistics for the score at 3 and 12 months were 0.78 (95%CI 0.71 to 0.83) and 0.77 (95%CI 0.72 to 0.82) respectively.ConclusionsThe RAPID score stratifies adults with pleural infection according to increasing risk of mortality and should inform future research directed at improving outcomes in this patient population.

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Patients with severe OSA have a higher prevalence of PFO with large shunts compared with control subjects. The ODI/AHI ratio is increased in patients with OSA with clinically significant shunts. PFO closure does not reduce nocturnal desaturation.