Blood flow in hepatic sinusoids in experimental hemorrhagic shock in the rat

Abstract

Sequential changes of blood flow in the hepatic sinusoids were measured in anesthetized rats which were subjected to the Wiggers method of hemorrhagic shock. The ventral margin of the liver was transilluminated by a fiber-optic light-guide and observed microscopically by a television method. Systemic arterial and portal venous pressures and several direct quantitative microvascular measurements in the sinusoids were recorded, including diameter, erythrocyte velocity, and erythrocyte flux, from which blood flow, hematocrit index, and flow resistance were indirectly calculated. In the initial phase of hemorrhage, hepatic sinusoids constricted with reduced blood flow but showed increased flow resistance and progressive hemoconcentration. When hemorrhage was severe, flow in about two-thirds of the sinusoids observed became stagnant; some of them also dilated while others remained constricted. The possible mechanism for these responses in the hepatic sinusoids to hemorrhagic shock is also discussed.