Hemodynamic profiles of etomidate vs propofol-phenylephrine combination for induction of anaesthesia in adult cardiac surgical patients

Propofol and etomidate are the two commonly used induction agents in anaesthesia practice. In patients who are critically ill and in patients with cardiovascular disease, etomidate is preferred as it causes less hypotension compared to propofol. But retrospective studies have proposed an association between the use of etomidate for anaesthesia induction and increased risk of mortality, morbidity in septic or critically ill patients.(1) In spite of these concerns, etomidate is favored for induction of anaesthesia in cardiac surgery patients, in whom hemodynamic stability immediately after induction of anaesthesia is paramount.

The important factors producing cardiovascular depression due to propofol are direct myocardial depression and decreased systemic vascular resistance (SVR). Phenylephrine is a pure alpha agonist which increases venous return and SVR which can counter propofol induced vasodilation. In non-cardiac surgery, studies have shown that phenylephrine mixed with propofol when administered for induction of anaesthesia reduces the hypotension due to propofol. (2,3,4)

   Our primary hypothesis is that if propofol-phenylephrine combination has non-inferior hemodynamic profiles to that of etomidate, the former can replace the latter.