Impact of sleep on ventilation and gas exchange in chronic lung disease

Sleep has many effects on breathing, all potentially adverse, ranging from the respiratory centre to the lower airways and chest wall. The overall effect is to diminish ventilation with consequent hypoxaemia and hypercapnia. These physiological changes can have major adverse effects on patients with chronic lung disease, particularly if already hypoxaemic. Patients with obstructive airway disease are particularly adversely affected during sleep with hypoventilation and reduced tidal volume, whereas patients with interstitial disease maintain overall ventilation although respiratory frequency falls. Sleep-related effects are most pronounced in rapid-eye-movement (REM) sleep and can have significant cardiovascular consequences including sleep-related cardiac arrhythmias and pulmonary hypertension and can also predispose to nocturnal death, particularly during acute exacerbations.