RESUMEN

Background Middle-ear surgery commonly performed under a microscope requires a bloodless field provided by hypotensive anesthesia. Our objective was to study the effects of dexmedetomidine on propofol consumption and intraoperative hemodynamic stability. Methods One hundred adults undergoing elective middle-ear surgery were randomized into two groups. The propofol+dexmedetomidine group (Group PD) received a loading dose of dexmedetomidine 1µg/kg in 10ml normal saline over 10min followed by infusion of the same at 0.5µg/kg/h. Propofol-only group (Group P) received 10ml normal saline over 10min followed by an infusion of the same. General anesthesia was induced with intravenous morphine, propofol, and vecuronium, and maintained with propofol, oxygen, and N2O. During microscope use, we aimed to maintain mean arterial pressure (MAP) within 60-69mmHg. Results There was no significant difference in the mean (SD) consumption of propofol [Group P 8.6 (2.1)mg/kg/h vs Group PD 8.1 (1.5)mg/kg/h, P=0.172]. The induction dose of propofol was significantly less in Group PD [1.8 (0.3) vs 2 (0.4)mg/kg, P<0.001]. Except for the baseline value, the heart rate was significantly lower in Group PD, P<0.001. The time duration during which MAP was within 60-69mmHg was higher in Group P [37.5 (36.8) vs 30.9 (38.3)min] though the difference was not statistically significant. The recovery was delayed in Group PD [25.4 (8.6) vs 17.6 (4.9)min, P<0.001]. Group PD had a significantly better operative field, P=0.0003. Conclusion The addition of dexmedetomidine did not reduce propofol consumption but reduced the induction dose of propofol. Propofol and dexmedetomidine combination provided comparable mean arterial pressure and better operative field but caused delayed recovery.