[Relevance of sleep for patients with lung diseases]

Sleep is characterized by a profound change of load and capacity of the respiratory system. Load increases due to a rise in upper and lower airway resistance. Capacity decreases due to reduced chemosensitivity, a decrease in muscle activity and minute ventilation. Whereas these changes do not lead to relevant blood gas changes and do not disturb sleep in healthy subjects, patients with respiratory diseases frequently show the first symptoms of their disease during sleep. Pulmonary diseases in which sleep plays an important role are asthma, COPD, hypercapnic respiratory failure, sleep disordered breathing, the overlap-syndrome and cystic fibrosis. Medical history should include sleep and complaints during the night. In asthmatics peak-flow measurements during the night may provide valuable information. In all other disorders mentioned, nocturnal ambulatory recording of respiration and arterial oxygen saturation often allow the detection of relevant disorders of breathing during sleep. If ambulatory monitoring reveals relevant pathology, then further evaluation and treatment in the sleep laboratory are warranted.