Sleep disorders in chronic airflow obstruction.

Sleep is the period of greatest physiologic disturbance in chronic airflow obstruction and so is likely the time of greatest danger to these patients. Sleep in these patients aggravates gas exchange abnormalities resulting in secondary pulmonary hypertension and cardiac arrhythmias. The mechanism of these disturbances is not fully explained, but patients with chronic airflow obstruction do not characteristically have the sleep apnea syndrome. Patients with chronic airflow obstruction sleep badly, with less rapid eye movement sleep and increased sleep stage changes. Nocturnal oxygen therapy helps relieve pulmonary hypertension and may decrease cardiac arrhythmia, but has no effect on sleep profile.