Lung volumes at different depths of submersion

¹ Department of Physiology, The University of Buffalo, Buffalo, New York

Vital capacity and expiratory reserve volumes of the lung were measured in seven subjects in the supine position. These were reduced when subjects were submersed at depths of 10, 20, 30 and 40 cm below the surface while breathing through rigid tubes. The reduction in these lung volumes is similar to that observed when subjects are subjected to continuous negative pulmonary pressure. The equivalence of pressurization of the thorax by air and water is discussed. When man in the supine position is just submersed the resting lung volume changes are equal to that when a negative pulmonary pressure of 6 cm H₂O is applied.