[Sleep apnea syndrome].

Excessive daytime sleepiness (EDS) in certain patients with sleep apnea syndrome may be the result of intermittent upper airway obstruction during sleep. The possible occurrence of daytime hypertension and pulmonary hypertension (PH) in these patients has been emphasized. Transient and sometimes severe elevations of systemic and pulmonary arterial pressures during sleep as a result of intermittent upper airway obstruction may lead to EDS, daytime hypertension, and PH. The aim of the present study was to investigate whether daytime hypoxemia and hypoxemia during sleep contribute to EDS, daytime hypertension, and PH. The results indicate that: (1) sleep disturbance and blood gas changes while awake and asleep may play a role for EDS, although these abnormalities were not present in some cases, (2) hypoxemia while awake and asleep is probably not involved in daytime hypertension, and (3) mean resting pulmonary arterial pressure is correlated with daytime PO2, PCO2, %IBW, %FVC, and FEV1.0%, Cardiopulmonary hemodynamic function may return to normal in some patients who receive appropriate treatment.