Transcapillary Oncotic Pressure in the Edema of Congestive Heart Failure

Abstract

Tissue fluid and plasma oncotic pressure levels were measured in an unselected group of 13 patients presenting with congestive heart failure. Patients had a mean serum albumin of 3.6 g/dl ± (SD) 0.35; serum oncotic pressure was 22.23 ± 1.8 mm Hg; tissue fluid (lower leg) oncotic pressure was 0.985 ± 0.34 mm Hg. The oncotic pressure gradient between plasma and tissue fluid was 21.25 Hg ± 1.7. This is about 10 mm Hg greater than △π in normal man. The high value in congestive heart failure is a mechanism to protect against the formation of edema. The possible mechanisms responsible for the formation of edema in congestive heart failure are discussed.

A First-Order Design Requirement to Prevent Edema in Mechanical Counter-Pressure Space Suit Garments

“…For example, in the cited study of hepatic cirrhosis [10], non-survivors had a p d twice as negative as did survivors, who had low-normal capillary oncotic pressures. The state of congestive heart failure is qualitatively different than the other disease states, and we did not attempt to model all factors that affect fluid balance in congestive heart failure; in congestive heart failure, the low interstitial oncotic pressure acts to protect against the formation of edema [13], with the result that our model predicts a slightly negative volume flux in this state.…”