Sleep
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Randomized Controlled Trial Clinical Trial
Treatment of obstructive sleep apnea with a self-titrating continuous positive airway pressure (CPAP) system.
Conventional manually adjusted continuous positive airway pressure (CPAP) is an effective therapy for sleep-disordered breathing. We prospectively investigated the efficacy of a self-titrating nasal CPAP system in the acute treatment of obstructive sleep apnea (OSA) syndrome. Twenty patients with moderately severe OSA [apnea hypopnea index (AHI) > 15/hour] were enrolled in a randomized, controlled, prospective clinical trial. ⋯ An unsupervised study would have resulted in undertreatment of OSA. Based on a single-night laboratory study, self-titrating CPAP was well tolerated and improved OSA and sleep architecture comparable to manually adjusted CPAP. The future modifications of this prototype will require further research to assess its efficacy and safety in the laboratory and home environments before its recommendation for general long-term use.
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A population-based probability sample of elderly individuals (n = 426), who were originally studied between 1981 and 1986 (mean age at initial study was 72.5 years), were followed for mortality. Those with > or = 30 respiratory disturbances per hour of sleep had significantly shorter survival (p = 0.0034), but the respiratory disturbance index (RDI) was not an independent predictor of death. When Cox proportional hazards analysis was done, only age (the strongest predictor), cardiovascular disease and pulmonary disease were independent predictors of death. It may be that factors that are secondary to or associated with sleep-disordered breathing (SDB), such as cardiovascular or pulmonary disease, predispose these elderly to death.
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This paper, which has been reviewed and approved by the Board of Directors of the American Sleep Disorders Association, provides the background for the Standards of Practice Committee's parameters for the practice of sleep medicine in North America. The intent of this paper is to provide an overview of the surgical treatment of obstructive sleep apnea syndrome, to provide the basis for the American Sleep Disorders Association's practice parameters on this subject and to share our findings of metanalysis of previously published studies regarding uvulopalatopharyngoplasty. We searched MEDLINE from January 1966 through April 1993, with an update in February 1995, to provide a review of the application of surgical modifications of the upper airway to treat adults with obstructive sleep apnea syndrome. ⋯ Patients who achieve a favorable response with uvulopalatopharyngoplasty tend to have less severe obstructive sleep apnea than those who do not. For patients who demonstrate retrolingual narrowing or collapse, other surgical modifications have been described, such as lingualplasty, GAHM, and maxillomandibular osteotomy and advancement. The studies to support the use of the surgical treatment of obstructive sleep apnea syndrome contain biases related to small sample size, limited follow-up and patient selection.
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Comparative Study
The effect of hypoxia on baroreflexes and pressor sensitivity in sleep apnea and hypertension.
Many persons with sleep apnea are hypertensive. Forty-two subjects of similar age and weight were divided into four groups of hypertensives and normotensives with and without sleep apnea. All subjects had heart rate, blood pressure (BP), baroreflex sensitivity and pressor sensitivity to phenylephrine measured while breathing room air or 15% oxygen. ⋯ Episodes of sleep apnea lead to hypoxia, an initial period of hypotension and a subsequent increase in sympathetic nervous activity. Our studies suggest that apneics could have an exaggerated pressor sensitivity to norepinephrine. They might also have difficulty returning BP to normal levels, because hypoxia impaired baroreflexes.
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Chronic alveolar hypoventilation may present in an insidious fashion with nonspecific manifestations. The clinician should be aware of the potential for developing this condition in patients with certain thoracic and systemic diseases. ⋯ Therapy of chronic alveolar hypoventilation often focuses on elimination of the nocturnal deterioration in gas exchange, and recent applications of noninvasive positive pressure ventilation during sleep have proven useful in the management of individuals with obesity-hypoventilation syndrome, restrictive thoracic disorders, neuromuscular diseases and central causes for hypoventilation. It is unclear whether wide-spread application of nocturnal ventilatory support to patients with chronic ventilatory failure due to chronic obstructive pulmonary disease is of long-term benefit.