THE NATURE OF INTRAPERITONEAL AND INTRARECTAL PRESSURES

Abstract

A series of roentgenograms were exposed, each of which included the body of a dog supported in the erect position and one or two manometers filled with Skiodan which registered the pressure at some level in the peritoneal cavity. In this way intra-abdominal pressure and the vertical distance from the air-containing balloon in the abdomen to the dome of the diaphragm were simultaneously recorded. The intra-abdominal pressure was shown to be directly proportional to the vertical height of the hydrostatic column of abdominal organs above the point of measurement. Intrarectal .pressures in man in the supine position and tilted to 30[degree], 60[degree] and 90[degree] were similarly proportional to the vertical distance from the point of measurement in the ampulla of the rectum to the highest point on the diaphragm or anterior ab- dominal wall. This indicates that intra-abdominal pressure is essentially a hydrostatic type of pressure resulting from the overlying mass of movable abdominal organs. The intra-abdominal pressure may partly balance the venous pressure and in this way oppose pooling of blood within the. splanchnic reservoir.