Effects Of Midazolam On The Minimum Alveolar Concentration Of Sevoflurane In Adults

Objective The purpose of this study was to determine the effects of midazolam on the minimum alveolar concentration (MAC) of sevoflurane in adults.Methods Thirty ASA Ⅰ-Ⅱ female patients aged36-58yr, scheduled to undergo breast cancer modified radical mastectomy were enrolled in this study. The patients were divided into two groups using an airtight envelope method:a sevoflurane group and a sevoflurane combined midazolam group. Patients in the sevoflurane group were given saline(5ml) and patients in the sevoflurane combined midazolam group were given midazolam(0.1mg/kg) when anesthesia began. Anesthesia was induced with8%sevoflurane and intravenous remifentanil(1μg/kg). The end-tidal sevoflurane concentration was kept constant for more than15min before skin incision. MAC was determined using "up-and-down method". The patients'somatic responses were observed for60seconds after the incision.Results MAC of sevoflurane when used alone was2.4±0.2%. MAC of sevoflurane combined midazolam was2.1±0.2%. Midazolam reduced MAC of sevoflurane by12.5%.Conclusion Midazolam (0.1mg/kg) results in a12.5%decrease in the MAC of sevoflurane in female patients scheduled to undergo breast cancer modified radical mastectomy.