Relative rates of absorption of fluid and protein from the peritoneal cavity in cats

The relative rates of fluid and protein absorption from the peritoneal cavity of anesthetized cats were measured over 6 hours at an intraperitoneal pressure of 15 mm Hg and with intraperitoneal protein concentrations from 1-8 g%. The fractional absorption rates of fluid and protein did not change significantly over the 6 hours and were not significantly different from each other within each one hour period. In addition both fractional absorption rates were unaffected by the protein concentration of the fluid within the peritoneal cavity. Although the absolute rate of absorption is greatly increased by elevation of the intraperitoneal pressure, these data indicate that the process remains iso-oncotic as would be expected for lymphatic rather than transcapillary absorption.