Sleep 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. Diaphragmatic or upper airway muscle weakness and reduced chest wall compliance in patients with thoracic restrictive disorders enhance the severity of sleep-disordered breathing during REM sleep, worsening gas exchange abnormalities and sleep fragmentation and impairing daytime functioning. Although daytime respiratory function and nocturnal oxygen saturation are not well correlated, some markers may be useful for identifying patients with thoracic restriction at risk for sleep-disordered breathing. 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.