Protein Content in Lymph and Edema Fluids in Congestive Heart Failure

Abstract

Protein content of tissue fluid and lymph is not uniform and depends upon regional differences in capillary permeability modified by changes in capillary filtration pressure. Whereas increased pressure in freely permeable liver sinusoids promotes formation of excess liver and thoracic duct lymph and ascitic fluid high in protein, increased venous pressure in less permeable beds promotes formation of excess lymph and edema fluid progressively lower in protein content. To ascertain the influence of colloid osmotic (oncotic) and hydrostatic pressure on excess lymph and edema formation in congestive heart failure, a disorder characterized by generalized venous hypertension, protein content of lymph (thoracic duct, liver, and small intestine), intracavitary and peripheral edema fluid, and plasma were measured in 42 patients with cardiac failure. In "acute" heart failure, thoracic duct lymph and ascitic fluid have high protein content (85% and 68% of plasma protein respectively) and are derived primarily from the liver, but in "chronic" heart failure protein content of thoracic duct lymph and ascitic fluid are lowered (46% and 40% of plasma protein respectively) by lymph from extrahepatic sites. In both stages, pleural and leg edema fluid are comparatively low in protein content (26 to 44% and 3 to 8% of plasma protein respectively). In congestive heart failure, edema and intracavitary fluid form primarily in response to increased venous pressure which outside the liver is partially counterbalanced by increased effective plasma oncotic pressure.