[Effect of gravitational pulmonary atelectasis on expiratory airway closure].

The effect of gravitation +Gz (2-8 Gz, 5 min) combined with air or pure oxygen breathing on the lung volume and expiratory airway closure was studied in 9 subjects. It was demonstrated that lung atelectasis induced by oxygen breathing causes restriction of lung ventilation and obstruction of the peripheral airways. The authors discuss the effect of restrictive and obstructive disorders of lung ventilation on gas exchange and development of circulatory hypoxia during acceleration.