Studies on Hepatic Circulation in Hemorrhagic Shock, with Special Reference to the Significance of Blood Catecholamines

Abstract

Purpose Many reports have been documented in the literature dealing with hepatic circulatory changes and associated injury of the liver function in secondary shock. Several investigators have stressed the significance of blood pooling phenomenon in splanchnic area as one of the most characteristic features representing the irreversible state of hemorrhagic shock. However, the mechanism responsible for this phenomenon still remains to be solved. In this paper, we would attempt to clarify the effect of endogenous catecholamines on systemic and hepatic circulatory changes during hemorrhagic shock and to discuss the possible significance of these pressor amines in determining the course and severity of this condition. Method (1) A total of 25 mongrel dogs were used with anesthesia of intravenously infused thiopento-barbital sodium. (2) Portal vein pressure was obtained by a catheter advanced into the vessel from a splenic branch vein and by attaching the catheter to a water manomater. Inferior vena cava pressure was measured at the level of the vena cava ostia of the hepatic vein. (3) Total peripheral resistance was calculated by dividing mean arterial pressure by cardiac output. Splanchnic resistance was also calculated on the same principle. (4) After observing the control status, blood was removed gradually from the dog juglar vein, until mean arterial pressure was lowered to 50-60 mmHg up to 90 minutes from the onset of bleeding. Thereafter, no further hemorrhage was performed and arterial pressure was sustained at that level as possible. (5) Blood catecholamines were determined fluorometricaly by the improved BERTLER, CARLSSON and ROSENGREN'S method. Results (1) Inferior cava vein pressure and portal pressure With the beginning of hemorrhage, inferior cava vein pressure is reduced, while portal pressure remains unchanged or rather slightly rises, so that the resultant increase in porto-caval pressure gradient is observed despite a marked fall in arterial pressure.