Background: Vasodilatation and hypotension are thought to be harmful in patients with severe aortic stenosis. Etomidate is preferred to propofol for anaesthesia induction in haemodynamically unstable patients, but may disturb cortisol synthesis. We assessed the haemodynamic effects of etomidate vs. propofol as anaesthesia induction agents, and the effects of these drugs on cortisol concentrations, in patients with severe aortic stenosis. The main end-point of the study was the incidence of hypotension.
Methods: Sixty-six patients with severe aortic stenosis scheduled for elective aortic valve replacement were enrolled in the study. The patients were randomized to receive either propofol or etomidate for induction of anaesthesia. Haemodynamic parameters, i.e. mean arterial pressure (MAP), pulmonary capillary wedge pressure (PCWP) and cardiac index (CI), were measured. If MAP decreased below 70 mmHg for more than 30 s, phenylephedrine was administered. Serum cortisol concentrations were also measured.
Results: MAP decreased in all patients (P < 0.001). MAP decreased to a greater extent in patients receiving propofol than in those receiving etomidate (P = 0.006). Patients receiving propofol needed phenylephedrine more often than those receiving etomidate (20/30 vs. 8/30, P = 0.002). CI and PCWP decreased in both groups (P < 0.001), with no difference between the groups. Patients receiving etomidate had a lower serum cortisol concentration immediately after the operation than those receiving propofol (P < 0.001), but no differences between the groups were observed on the first post-operative morning.
Conclusion: Propofol is twice as likely as etomidate to evoke hypotension in anaesthesia induction of patients with severe aortic stenosis; however, etomidate transiently decreases post-operative serum cortisol concentrations.