A Study on Etomidate versus Propofol for Induction of General Anaesthesia- A Comparative Study

Abstract

Background and Objectives: Induction of anaesthesia is a critical part of anaesthesia practice. Sudden hypotension, arrhythmias and cardiovascular collapse are life threatening complications following injection of induction agent in hemodynamically unstable patients. It is desirable to use a safe agent with fewer adverse effects. Present clinical study was conducted to evaluate the induction time, hemodynamic changes like blood pressure, Heart rate during pre induction, induction and post induction and untoward effects like pain on injection, myoclonus and post operative nausea and vomiting.Methods: In a prospective, randomized, double blind study, 80 patients of ASA Grade І and II in the age group 18-65 years of either sex scheduled for elective surgery were divided into two groups of 40 each. Premedication was given as InjGlycopyrrolate, Midazolam, and Pentazocine. Induction was done with InjEtomidate 0.3mg/kg in Group “E” and InjPropofol 2mg/kg in Group “P” followed by injection succinylcholine 2mg/kg for intubation and anesthesia was maintained with 40% O2 +60% N2O and Isoflurane and intermittent vecuronium 0.05mg/kg. Two groups were compared with respect to the induction time, hemodynamic parameters like Blood pressure, Heart rate(HR) during Pre induction, Induction and Post induction were recorded. The induction time was calculated after loss of eye lash reflex. The adverse effects like pain on injection, myoclonus and post operative nausea and vomiting (PONV) during postoperative period observed.Results: Induction time was faster in Etomidate group compared to Propofol group. Mean induction time in Group E and Group P were 22.60±4.91 seconds and 26.95±3.86 seconds respectively. Time for induction in Etomidate was significantlyshorter compared to Propofolgroup( p value <0.05). Hemodynamic changes like Heart rate increased in Propofol group compared to Etomidate at 1min, 2min and 3min at induction and post induction and it was statistically significant(p value ≤0.001). Compared to Propofol group, Etomidate group patients showed stable Systolic blood pressure (SBP) at 1min, 2min and 3min at induction time and it was statistically significant(p value ≤0.001). After intubation, SBP decreased in Propofol group at 1 min, at 2 min compared to Etomidate group at 1min, at 2 min and it was statistically significant (p value≤ 0.001 at 1 min and p= 0.009 at 2 min). At 3 min, there no statistically significant difference of SBP among two group. Following induction, compared to Propofol group , Etomidate group patients showed stable Diastoloc blood pressure(DBP) at 1min, 2min and 3min at induction time and it was statistically significant(p value =0.002 at 1 min, p =0.001 at 2 min and p =0.027 at 3 min). After intubation, there no statistically significant difference of DBP among two group. Following induction, compared to Propofol group , Etomidate group patients showed stable Mean arterial pressure(MAP)at 1min, 2min and 3min at induction time and it was statistically significant(p value <0.001). After intubation, there is statistically significant difference of MAP among two groups at 1 min (p value 0.028). There is no statistically significant difference of MAP among two groups at 2 min (p value 0.088) and at 3 min (p value 0.238). Compared to Propofol group, pain on injection is less in Etomidategroup(p<0.001). 3 patients showed myoclonus(grade1) and 5 patients showed PONV in Etomidate group.Conclusion: By the present study, Etomidate is better intravenous inducing agent compared to Propofol for its hemodynamic stability, less incidence of pain on injection and less induction time. Only drawback was incidence of myoclonus and Post operative Nausea and Vomiting.