CHANGES IN SERUM CORTISOL LEVELS AND HEMODYNAMIC RESPONSES: COMPARISON OF ETOMIDATE AND THIOPENTONE FOR INDUCTION OF GENERAL ANAESTHESIA IN ELECTIVE SURGERIES

Abstract

Background: Etomidate offers a clear benefit of improved cardiovascular stability with reduced risk of hypotension during anaesthesia.(6)Even though it has a highly favourable cardiovascular profile, the use of etomidate had dramatically decreased since 1983 until 2001.This was because its use was associated with adrenal suppression, which some believe is associated with poor outcome, particularly in critically ill patients and those with sepsis(7,8).The effect on serum cortisol levels with the newer preparation of etomidate has still not been studied in ASA I/II patients. Hence, this study was designed to compare the effects of induction with a single bolus dose of intravenous etomidate and thiopentone on serum cortisol levels. Methods: In this prospective, randomized study 64 patients, 20-65 years of age, undergoing general anaesthesia for elective surgeries were randomly assigned to one of the two groups receiving either thiopentone 5 mg kg−1 (Group T) or etomidate 0.3 mg kg−1 (Group E) for induction of anaesthesia. Serum cortisol levels were measured preoperatively, 4 hours and 24 hours after induction. Hemodynamic parameters and adverse effects were also assessed. Results: In patients receiving etomidate, mean serum cortisol levels decrease from 17.86 ± 2.97 µg/dl (baseline) to 14.02 ± 2.91 µg/dl 4 hrs after induction. By 24 hours, the mean serum cortisol levels had returned to baseline values (17.71 ± 3.06 µg/dl). The decrease in mean serum cortisol levels at 4 hrs was statistically significant, though it remained within the normal reference range (6-25µg/dl). In group T, mean serum cortisol levels did not show any significant change (from 18.85 ± 2.85 µg/dl to 19.53 ± 3.28 µg/dl) 4 hrs after induction and remained near the baseline at 24 hrs postoperatively. Conclusion: To conclude though both etomidate and thiopentone have a stable hemodynamic profile in ASA I/II patients, the use of etomidate is associated with a decrease in serum cortisol levels and a high incidence of myoclonus. Categories: Medical Education, Endocrinology/Diabetes/Metabolism, Anesthesiology