Influence of free blood exchange between two animals on some body fluid compartments.

Abstract

The changes in systolic, diastolic and mean arterial pressures, heart rate, cardiac output, pulmonary and peripheral vascular resistances, respiratory and metabolic processes, extracellular volume and hematocrit have been studied in a total of 44 dogs before, during and after cross circulation. Free flow of blood from the carotid artery of one animal to the external jugular vein of the other animal was allowed for 60 minutes. The mean arterial pressure and cardiac output findings confirmed previously reported findings but were based on the results obtained from a larger number of animals. A significant decrease in the systolic, diastolic and mean pressures which followed the same pattern for both members of the pair were observed during the open shunt phase. During the 60 minutes of the post shunt period, the arterial pressures returned toward control levels. A slight but insignificant increase in pulmonary and peripheral vascular resistance occurred. Cross circulation does not alter significantly the oxygen consumption, carbon dioxide production, heat production, respiratory quotient and minute volume of either of the pair. A significant decrease in the extracellular space, blood and plasma volumes was observed consequent to cross circulation.