Effect of pre-treatment on induction of anaesthesia with etomidate: A comparison between dexmedetomidine and midazolam–fentanyl combination

Abstract

Background: Because of its prompt onset of action and clearance, the use of etomidate as an anaesthetic induction agent is increasing in clinical practice. However, etomidate-induced myoclonus (EIM) remains a prevalent issue. Such myoclonic activity can be prevented by the administration of drugs that inhibit subcortical neuronal activity. Aims: This study was designed to compare the effects of pre-treatment with dexmedetomidine and fentanyl–midazolam combination on EIM as well as on attenuation of pharyngolaryngeal reflex. Materials and Methods: One hundred adult patients with the American Society of Anesthesiologists Grades 1 or 2 posted for elective surgery were enrolled and were randomly divided into two groups of 50 patients each. Group D received dexmedetomidine (1 μg/kg) in over 10 min and Group F received midazolam (0.02 mg/kg) + fentanyl (2 μg/kg) intravenously. Haemodynamic variables, incidence and severity of myoclonus were recorded. Results: The incidence of EIM was lower in Group F (26%) when compared to Group D (40%), but the difference was not statistically significant (P = 0.28). Eighteen per cent of the subjects in Group F had Grade 1 myoclonus as compared to 32% of Group D, whereas 8% of the subjects in Group F had Grade 2 myoclonus as compared to 6% of Group D. None of the patients in Group F experienced myoclonus of Grade 3, whereas 2% of the subjects had Grade 3 myoclonus. Conclusion: Administration of a combination of fentanyl and midazolam, along with dexmedetomidine as a pre-treatment, has been found to be an effective strategy for mitigating the incidence of myoclonus.