Melatonin premedication does not enhance induction of anaesthesia with sevoflurane as assessed by bispectral index monitoring

Abstract

Introduction: Exogenous melatonin has sedating and hypnotic actions. The present prospective double-blind randomised study investigated the effect of melatonin premedication on the induction of anaesthesia with sevoflurane.

Methods: 71 women of reproductive age, scheduled for a hysteroscopy, were randomised into the melatonin or the control group. 30 minutes before the induction of anaesthesia, patients in the melatonin and control groups sublingually received 9 mg of melatonin or placebo, respectively. In the operating room, patients were attached to a standard monitor and bispectral index (BIS) monitor. Anaesthesia was induced with 8 percent sevoflurane in oxygen via an anaesthetic system primed with 8 percent sevoflurane. BIS values were recorded every 30 seconds, during the first 300 seconds of sevoflurane administration. Inspired and expired sevoflurane concentrations, heart rate and oxygen saturation were also recorded at the same time intervals. Noninvasive blood pressure was recorded before and after the completion of measurements.

Results: BIS values (p-value is 0.725, F is 0.125, degrees of freedom [df] 1), inspired (p-value is 0.468, F is 0.535, df 1) and expired (p-value is 0.388, F is 0.756, df 1) sevoflurane concentrations, heart rate (p-values is 0.516, F is 0.427, df 1) and oxygen saturation (p-value is 0.401, F is 0.717, df 1), did not differ between the two groups, at any time point of measurement. Systolic blood pressure before (p-value is 0.131, t 1.530, df 67) and after measurement (p-value is 0.8288, t 0.218, df 54) as well as diastolic blood pressure before (p-value is 0.370, t 0.902, df 67) and after measurement (p-value is 0.764, t 0.302, df 54) did not differ between the two groups.

Conclusion: Melatonin premedication under the present study design failed to enhance the induction of anaesthesia with sevoflurane.