EFFECT OF ANAESTHESIA WITH CYCLOPROPANE, HALOTHANE OR THIOPENTONE ON THE VASCULAR COMPARTMENT IN SHEEP

Abstract

SUMMARY Measurements of the volume and protein content of the plasma, and the red cell and haemoglobin content, haematocrit and gas tension of the blood were made on normal, adult sheep during three consecutive 2-hour periods: control, anaesthesia and recovery. During the period of anaesthesia, cyclopropane, halothane or thiopentone was administered. Red cells were removed from the circulation during the control periods and during anaesthesia with thiopentone or halothane, but returned during the recovery periods. The red cell concentration increased both during and after the administration of cyclopropane, and reached a value 30 per cent higher than the mean concentration present during the control period. Cyclopropane anaesthesia was not accompanied by a significant loss of fluid or protein from the circulation, but the rate of protein loss increased after the cyclopropane was withdrawn. No significant changes in either the volume of plasma or the total plasma protein occurred during the early stages of either halothane or thiopentone anaesthesia, but in each case the mean plasma protein concentration was significantly lower during anaesthesia than during the control period.