Book Description

"Static relaxation pressure volume curves of the thorax and lung were obtained on 4 trained subjects while in the supine position on the human centrifuge at 1, 2, 3, and 4 g. As acceleration increased, the intrapulmonic pressure increased for a constant volume shifting the pressure volume curve downward and to the right. Compliance of the thorax and lung decreases from 1 to 4 g as the result of the fall in pulmonary mid-position. Inspiration during 4 g acceleration, regardless of the end expiratory position was always active. Elastic work of breathing approximately doubles from 1 to 4 g while non-elastic work does not change. Absolute lung volumes during acceleration decrease proportionately with the exception of residual volume which did not change. Since these changes are similar to those described during negative pressure breathing, positive pressure breathing is suggested as a means by which respiration during forward acceleration may be improved and toleration increased."--Abstract.