Clinical Analysis of Propofol, Etomidate and an Admixture of Etomidate and Propofol for Induction of General Anaesthesia

Objective: To compare the clinical outcome following induction of general anaesthesia with intravenous (IV) injection of propofol (P), etomidate (E) or a 50% admixture of propofol and etomidate (PE). Methods: In this prospective, randomised, double-blind controlled study, patients 18-60 years of age who were undergoing elective surgery with general anaesthesia were randomised to receive either propofol 2.5 mg kg(-1) IV (group P; n=30), etomidate 0.3 mg kg(-1) IV ( group E; n=30) or an admixture of etomidate 0.2 mg kg(-1) IV and propofol 1 mg kg(-1) IV (group PE; n=30) as the induction agent. The haemodynamic response was first recorded at baseline, then at 1 minute following administration the study drug, and 1, 3, 5, 10, 20, 30 and 40 minutes following intubation. Perioperative symptoms such as myoclonus, pain upon injection and/or vomiting upon induction as well as postoperative nausea were recorded. Results: We observed a decrease in systemic haemodynamics from baseline following induction in group P compared to groups E and PE (p<0.05). Incidence of myoclonus was reduced from 76.6% in group E to 6.6% in group PE (p<0.001). There was also a reduction in reported pain upon injection in group PE compared to group P (p<0.001). Although we found no statistically significant difference between the three groups when assessing postoperative nausea and vomiting, these symptoms were more prevalent in groups E and PE than in group P. Conclusion: Using an admixture of etomidate and propofol as the induction agent reduced the incidence of side effects observed with use of either drug alone such as pain upon injection, myoclonus and haemodynamic instability.