Comparison of pretreatment with dexmedetomidine with midazolam for prevention of etomidate-induced myoclonus and attenuation of stress response at intubation: A randomized controlled study.

Background and Aims: Myoclonus is a common problem during induction of anesthesia with etomidate. A variety of drugs have been used to decrease the incidence of myoclonus. In this study we compared the effects of dexmedetomidine and midazolam pretreatment on the incidence of etomidate induced myoclonus. We also studied the effects of these drugs on attenuation of stress response at laryngoscopy and intubation on induction with etomidate.

Material and Methods: Eighty adult patients (18 to 60 years age) of either sex, American Society of Anestheiologists physical status I and II undergoing elective general surgeries under general anesthesia were randomly allocated into two groups. Group D patients received Inj. Dexmedetomidine (0.5 μg/Kg) and Group M received Inj. Midazolam (0.015 mg/Kg) in 10 ml saline over ten minutes. Myoclonus was graded after intravenous administration of etomidate (0.3mg/Kg) and hemodynamic response to laryngoscopy and intubation were observed at various time intervals. Analysis of statistical data was done using Statistical Package for Social Sciences (SPSS) version 21.0. Quantitative variables were compared using Independent T Test/Mann Whitney test (for non-parametric data). Qualitative variables were compared using Chi-Square test/Fisher's Exact Test. A P value of < 0.05 was considered statistically significant.

Results: In Group D, 22 out of 40 (55%) patients did not have any myoclonus during induction with etomidate, and none of the patients had grade 3 (severe) myoclonus. In Group M, 19 out of 40 patients (47.5%) had grade 2 (moderate) and 6 patients (15%) had grade 3 myoclonus. Stress response due to intubation was more effectively suppressed by dexmedetomidine as compared to midazolam.

Conclusion: Incidence of myoclonus among patients who underwent pre-treatment with dexmedetomidine was significantly lesser than those who underwent pre-treatment with midazolam. Greater degree of attenuation of stress response in the dexmedetomidine group was observed as compared to midazolam group.