Sleep-related disorders and chronic obstructive pulmonary disease.

Sleep-disordered breathing is ubiquitous in COPD. Sleep-related hypoxemia results from hypoventilation attributable to reduced respiratory drive and abnormal mechanics, and from probable changes in V/Q matching. An overlap syndrome combining COPD and OSA also has been described. Disturbances in cardiac, hematologic, and pulmonary function, as well as sleep complaints, are common when COPD is complicated by nocturnal hypoxemia, and these sequelae are even more common when COPD and OSA coexist. Treatment with oxygen is the mainstay for COPD and sleep desaturation alone, whereas combined nasal CPAP and oxygen are most frequently used for the overlap syndrome.