Seminars in respiratory and critical care medicine
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Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death, affecting 14 million adults in the United States. Symptoms related to sleep disturbances are common in moderate to severe COPD, particularly in elderly patients, in the form of morning tiredness and early awakenings. One major cause of morbidity in this population is abnormalities in gas exchange and resultant hypoxemia. ⋯ They include decreased functional residual capacity, diminished ventilatory responses to hypoxia and hypercapnia, impaired respiratory mechanical effectiveness, diminished arousal responses, respiratory muscle fatigue, diminished nonchemical respiratory drive, increased upper airway resistance, and the position of baseline saturation values on the oxyhemoglobin dissociation curve. Smoking cessation, bronchodilation, and pulmonary rehabilitation are cornerstones of treatment of COPD. Improvement in lung mechanics and gas exchange should lead to better sleep quality and health status.
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Semin Respir Crit Care Med · Feb 2005
ReviewPortable monitoring in the diagnosis of the obstructive sleep apnea syndrome.
Portable monitors are classified into three levels (Level II, III, and IV) with decreasing measurements of sleep and respiratory variables. A full overnight sleep study with respiratory measurements and sleep staging (polysomnography) unattended by a sleep technician is Level II, three or more respiratory channels and heart rate generally without sleep staging either attended or unattended is Level III, and one or two channels attended or unattended, usually including oximetry, is Level IV. ⋯ The role of portable monitoring is evolving but at this time cannot substitute for attended polysomnography as a standalone approach. The exact place of portable monitoring and the cost-benefit depends on local circumstances and cannot be generalized at this time.
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Positive airway pressure is standard therapy for patients with obstructive sleep apnea. It comes in three basic varieties: (1) continuous positive airway pressure (CPAP), (2) bilevel positive airway pressure (BPAP), and (3) autotitrating positive airway pressure (APAP). When properly titrated, positive airway pressure devices minimize the number of sleep-related breathing disorder events, often producing dramatic results. ⋯ The titration process is presented in a step-by-step manner and titration grading is explained. Issues surrounding the interface, acceptance, utilization, and side-effects are discussed. Finally, we present an assortment of approaches for troubleshooting clinical problems commonly encountered among patients being treated with positive airway pressure therapy.
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Semin Respir Crit Care Med · Feb 2005
ReviewCentral sleep apnea in congestive heart failure: prevalence, mechanisms, impact, and therapeutic options.
Heart failure due to left ventricular systolic dysfunction is a prevalent syndrome and associated with morbidity, mortality, and huge economic cost. According to reports from several laboratories, a large number of patients with heart failure have central sleep apnea. ⋯ Several treatment options, including use of nocturnal supplemental oxygen, positive airway pressure devices, and theophylline have been systematically studied and have been shown to improve central sleep apnea. Long-term studies, however, are necessary to determine the impact of therapy on natural history of left ventricular systolic dysfunction.
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Semin Respir Crit Care Med · Feb 2005
ReviewSleep in restrictive and neuromuscular respiratory disorders.
Thoracic restrictive disorders (i.e., chest wall deformities or neuromuscular diseases), may predispose to sleep-disordered breathing, poor sleep quality, and nocturnal hypoventilation. These disorders intensify the effects of reductions in both respiratory center output and central chemosensitivity and increases in upper airway resistance that occur with the onset of sleep. Normally, rapid eye movement (REM) sleep suppresses the activity of nondiaphragmatic breathing muscles, further reducing ventilation. ⋯ Although some patients may respond to continuous positive airway pressure (CPAP) alone, noninvasive positive pressure ventilation (NPPV) is a more important part of disease management for patients with restrictive thoracic disorders. This technique improves nocturnal ventilation and sleep quality but may also contribute to sleep fragmentation in some patients. If the patient is an unsuitable candidate for or fails NPPV, tracheostomy mechanical ventilation should be considered.