Investigation of the Effects of Intravenous Dexmedetomidine on Desflurane Mac Value Using by Bis Monitorisation

Abstract

Aim: In this study, we aimed to investigate the effects of intravenous dexmedetomidine on desflurane MAC value by BIS monitorisation. Materials and Methods: Sixty adult patients with ASA I-II groups were participated in this study. Patients were randomly divided to two groups with thirty patients in each group. Patients were not prcmedicad. The depth of the anesthesia was monitorised by BIS. The induction of anesthesia was performed with 2 μg kg-1 fentanyl, 2.5 mg kg-1 propofol and 0.1 mg kg -1 vecuronyum. A bolus injection of dexmedetomidine was administered at a rate of 1 μg kg-1 in ten minutes, and then infused at a rate of 0.5 μg kg-1 hr-1 to group I. However, physiological saline was administered to group II in the same manner. Anesthesia was maintained with a mixture of. 40% O2 and 60% N2O with desfluran in order to keep BIS values between 40-50. Heart rate, blood pressure, MAC values of the agent were measured with five minutes intervals. Central temperature, SpO2, ETCO2, and BIS values were measured with ten minutes intervals . Results: No statistically significant difference were seen between groups according to demographic data. BIS values in group I was lower than group II during the first ten minutes (p<0,05) MAC values in group I were lower than group II (p<0,001). There were no difference between two groups in respect to mean arterial pressure. Atropin was given to eleven patients in Group I, but not given to any patient in Group II (p<0,001). No statistically difference was seen between groups in respect to ETCO2 and temperature values. SpO2 values in group I were found lower than group II at the tenth minute before the induction (p<0.05). Conclusion: Dexmedetomidine can be used adjuvantly in general anesthesia, as it decreases MAC values and confirms a stable haemodynamy during induction. However, dexmedetomidine should be made cautiously regarding to its bradycardic effect.