Midazolam and etomidate for induction of anaesthesia in ophthalmic surgery

Abstract

Objectives: To assess the effect of midazolam 0.02 mg/kg administered with etomidate on the incidence of myoclonus and the dose requirement for etomidate to induce general anaesthesia.
Design: Double blind randomised control trial.
Setting: Two urban teaching hospitals in Durban, Kwa Zulu Natal (KZN).
Patients: 60 patients older than 60 years of age undergoing intraocular surgery.
Outcome measures: Etomidate dose required for loss of verbal contact (dose V) and loss of eyelash reflex (dose E). Myoclonus assessed by means of a three-point scale (0-nil; 1-mild; 2-severe) 30 sec after the last dose of etomidate. Duration of recovery from cessation of anaesthesia to first response to verbal command.
Results: No significant difference in myoclonus or dose requirement for etomidate could be demonstrated. There was no difference in haemodynamic variation between the groups and recovery time was not prolonged.

Conclusion: Midazolam 0.02 mg/kg given with etomidate for induction of anaesthesia does not reduce myoclonus or dose requirement for etomidate. Further studies may be undertaken to assess the usefulness of larger doses of midazolam for co-induction or oral premedication with midazolam.