Transcapillary oncotic pressure in the edema of congestive heart failure.

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 delta pi 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.