Respiratory changes in pleural pressures at different sites and body positions

Publisher Website
Google Scholar
Abstract
Changes in pressures during respiration were measured simultaneously from different sites in the pleural space of eight anesthetized dogs in the supine, left lateral, and prone body positions. Saline-filled, radtopaque catheters connected to strain-gauge manometers were inserted percutaneously into the right pleural space by an air-tight technique, and their tips were placed at ventral and dorsal sites. In six of these dogs, intra-esophageal pressure was also recorded. Respiratory pressure amplitude ([DELTA] P = difference between mean end-expiratory and minimal inspiratory pressures) was systematically greater at ventral sites than at dorsal sites in supine, prone, and lateral positions. Values of [DELTA] P in the cephalad portion of the thorax were systematically less than those toward the lung bases, both at ventral and at dorsal sites. Ventral [DELTA] P values were larger than esophageal [DELTA] P values in all body positions. Dorsal [DELTA] P values were significantly less than esophageal values in the supine position but no systematic differences were observed between these two values in the prone position.