Sleep & breathing = Schlaf & Atmung
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We hypothesized that an improvement in systemic blood pressure (BP) during continuous positive airway pressure (CPAP) treatment of obstructive sleep apnea (OSA) would be related to severity of hypertension (HTN), morphometric parameters such as body mass index, and level of CPAP adherence. We tested this hypothesis with a retrospective review of 85 consecutive OSA patients who had completed diagnostic and CPAP titration polysomnograms and were equipped with a CPAP-adherence monitoring system for a minimum of 1 month of observation. Sphygmomanometer-obtained BP readings were compared at baseline and after 4-6 weeks of CPAP therapy. ⋯ Those with a BP below the hypertensive range of 140/90 on presentation did not have a significant drop in BP with CPAP. There were no significant changes in systolic, diastolic, or mean BP when patients were categorized by the severity of HTN, as determined by the number of antihypertensive medications prescribed or if they were categorized by the degree of CPAP adherence, objectively determined by the average use of more or less than 4 h/night. We conclude that HTN at initial presentation is among the most important indicators of potential benefit of CPAP administration on BP.
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The obstructive sleep apnea syndrome (OSAS) is associated with cardiovascular abnormalities including left ventricular hypertrophy, left ventricular diastolic dysfunction, and endothelial dysfunction. The present study evaluated whether N-terminal pro-B-type natriuretic peptide (NT-proBNP) and peak oxygen consumption (peak VO(2)), both integral markers of cardiovascular function, are related to OSAS severity. In addition, we tested whether NT-proBNP levels depend on body composition in OSAS patients, similar to what has been reported in patients without OSAS. ⋯ The lack of a relationship between NT-proBNP and OSAS severity is not due to a significant influence of body composition on NT-proBNP. There is an association between higher NT-proBNP and lower peak VO(2), indicating that NT-proBNP is a marker of cardiorespiratory fitness in patients with OSAS. However, the association is too weak to be clinically useful.
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Clinical Trial
Moving beyond empiric continuous positive airway pressure (CPAP) trials for central sleep apnea: a multi-modality titration study.
There is no universally accepted method to determine effective therapy for central sleep apnea (CSA). Continuous positive airway pressure (CPAP) applied acutely most often does not eliminate apneas and hypopneas. We hypothesized that the application of two or more therapeutic modalities after the diagnostic phase of polysomnography, a multi-modality titration study (MMTS), would identify a successful CSA treatment more often than a standard split-night study (SNS) and obviate the need for additional polysomnograms to determine a successful therapy. ⋯ Adaptive servo-ventilation was the most successful modality tested, yielding 36/46 (78.3%) successes. Trials of additional modalities following a failed trial of CPAP often produce a successful option that may guide therapy in patients with CSA. This approach may lead to establishing the diagnosis and treatment plans faster, while reducing unnecessary testing.
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Randomized Controlled Trial Multicenter Study
Safety of ramelteon in individuals with mild to moderate obstructive sleep apnea.
Ramelteon is a selective MT(1)/MT(2)-receptor agonist indicated for insomnia treatment. Because it has no depressant effects on the nervous system, it is not expected to affect the control of breathing. The potential effects of ramelteon on apneic and hypopneic events and arterial oxygen saturation (SaO(2)) in individuals with obstructive sleep apnea were assessed. ⋯ Adverse events were reported by three subjects in the ramelteon group: headache (n = 2) and urinary tract infection (n = 1). No adverse events were reported with placebo. Ramelteon was well-tolerated and, as expected, did not worsen sleep apnea when administered to subjects with mild to moderate obstructive sleep apnea.
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Patients with obesity hypoventilation syndrome (OHS) have a lower quality of life, more healthcare expenses, a greater risk of pulmonary hypertension, and a higher mortality compared to eucapnic patients with obstructive sleep apnea (OSA). Despite significant morbidity and mortality associated with OHS, it is often unrecognized and treatment is frequently delayed. The objective of this observational study was to determine the prevalence of OHS in patients with OSA seen at the sleep disorders clinic of a large public urban hospital serving predominantly minority population and to identify clinical--not mechanistic--predictors that should prompt clinicians to measure arterial blood gases. ⋯ Only 3% of patients with a serum bicarbonate level <27 mEq/l had hypercapnia compared to 50% with a serum bicarbonate > or =27 mEq/l. In conclusion, OHS is common in severe OSA. A normal serum bicarbonate level excludes hypercapnia and an elevated serum bicarbonate level should prompt clinicians to measure arterial blood gases.