A comparison of the haemodynamic effects of propofol and isoflurane in pregnant ewes

The purpose of this study was to compare the effects of inhaled isoflurane and a constant infusion of propofol on maternal haemodynamics and uterine arterial and umbilical venous flows in pregnant ewes. Late term pregnant ewes (n = 5) were randomly assigned to receive either inhaled isoflurane or an intravenous infusion of propofol for 1 h, each on separate occasions. Maternal systemic arterial, right atrial and pulmonary arterial blood pressures, cardiac index, systemic vascular resistance index, stroke volume index, heart rate, and uterine arterial and umbilical venous flows were determined over the 1 h period of each treatment. Data were analysed using an univariate analysis of variance for repeated measures performed on the ranks of the data. Propofol anaesthetized ewes had significantly higher heart rate (P = 0.0040), mean arterial pressure (P = 0.0003) and cardiac index (P = 0.0475) compared to isoflurane anaesthetized ewes. There were no significant differences in uterine arterial flows, umbilical venous flows, or other measured variables. Continuous propofol infusions maintain maternal haemodynamics at significantly higher levels than does inhaled isoflurane, while uterine arterial and umbilical venous flows do not differ significantly.