Transvascular Fluid Fluxes During Severe, Prolonged Canine Hemorrhagic or Endotoxin Hypotension

Abstract

This paper is an attempt to summarize our findings related to transvascular fluid fluxes in circulatory shock states. One aim was to determine if fluid filtration into tissue (especially skeletal muscle) during severe, prolonged hypotension is an important determinant of irreversibility in circulatory shock states resulting from blood loss or endotoxin. Experiments were conducted on mongrel dogs anesthetized with Na pentobarbital. The forelimb was selected as the test organ since it largely comprises skin and skeletal muscle. Since total body soft tissue mass is mainly composed of these two tissues, fluid fluxes in skin and skeletal muscle would be of paramount importance in shock states. Transvascular fluid fluxes in collateral-free, innervated, naturally perfused canine forelimbs were inferred from changes in organ weight and total and segmental (large artery, small vessel, large vein) vascular resistances (1–4). Brachial venous outflow was used as an index of skeletal muscle blood flow and cephalic venous outflow was used as an index of skin blood flow.