Pleural pressures at dorsal and ventral sites in supine and prone body positions.

Publisher Website
Google Scholar
Abstract
In-trapleural pressures at 2-5 different sites in the right pleural space of 9 anesthetized dogs were measured with fluid-filled catheters while the dogs were supported in the supine and prone positions by means of a half-body cast. Tips of the intrapleural catheters were placed at heart level in the cephalocaudad direction at ventral (retro-sternal) and dorsal (paravertebral) sites. In the supine position mean end-expiratory pressure gave an average gradient of 0.64 cm H2O per cm vertical distance between the 2-recording sites. In the prone position the average gradient was 0.91 cm H2O per cm vertical distance. Esophageal pressures were more positive than pleural pressures at the same vertical height in the thorax by about 2-5 cm H2O. During the increase in weight induced by acceleration, pleural pressure differences were increased roughly in proportion to the G level. The resulting intrathoracic pressure imablances would be expected to be a potentially serious hazard during the launch and reentry phases of space flights.