Haemodynamic Effects and Uptake of Enflurane in Patients Undergoing Cardiac Surgery: Good versus Poor Myocardial Function

Abstract

We measured haemodynamic effects and uptake of enflurane in patients undergoing cardiac surgery utilizing a standard anaesthetic technique of fentanyl 15 mcg/kg nitrous oxide 50%/enflurane 1%. We divided 22 patients preoperatively into two groups according to standard criteria: good and poor myocardial function. Regression lines could be drawn illustrating the relationship of cardiac output and uptake (at 1 minute: r = −0.56, P < 0.01; at 5 minutes: r = −0.43, P < 0.05; at 30 minutes: r = −0.31, P=0.08). Although patients with poor myocardial function had decreased uptake of enflurance (approximately 10–20%), this did not reach statistical significance. Fentanyl/nitrous oxide/enflurane anaesthesia provided stable haemodynamics, even in patients with poor myocardial function. Both groups had a shunt fraction of approximately 10% and an arterial: end-tidal carbon dioxide difference of approximately 3–4 mmHg.