Background: Dexmedetomidine induces less change in hemodynamic values during the extubation period. This drug may be useful in anesthetic management requiring smooth emergence from anesthesia. We sought to determine the effects of co-administration of dexmedetomidine on the recovery profiles from sevoflurane and propofol, which usually provide safe and rapid recovery when administered alone.
Methods: Sixty patients undergoing lower abdominal surgery were randomly divided into four groups according to the anesthetic to be administered; namely, sevoflurane (group S), propofol (group P), both sevoflurane and dexmedetomidine (group SD), or propofol and dexmedetomidine (group PD) as maintenance general anesthetics. After induction, anesthesia was maintained with sevoflurane (0.6%-1.5%) in group S, propofol (2-5 mg/kg/h) in group P, sevoflurane and dexmedetomidine (1 microg/kg over 10 min followed by 0.4 microg/kg/h until the end of surgery) in group SD, and propofol and dexmedetomidine in group PD with continuous epidural infusion. Bispectral Index values were maintained within 45 +/- 5 by changing the concentration of sevoflurane or the infusion rate of propofol in all groups. The time between the interruption of maintenance general anesthetics and eye opening was measured. Postoperative cognitive function was evaluated using the Short Orientation Memory Concentration Test.
Results: The time to eye opening of groups S (8.5 +/- 2.5 min, mean +/- SD; n = 15) and SD (12.0 +/- 3.3 min) were comparable, whereas that of group PD (21.7 +/- 7.1 min) was longer than that of group P (11.0 +/- 4.4 min). The time to eye opening of group PD was significantly (P < 0.001) longer than those of the other three groups. The scores of Short Orientation Memory Concentration Test between groups S and P were similar and were not changed by co-administration of dexmedetomidine.
Conclusion: When co-administered with dexmedetomidine, sevoflurane produced a shorter time to eye opening than propofol. Postoperative cognitive function was not affected by dexmedetomidine administration. These results suggest dexmedetomidine may delay recovery when given as an adjuvant to propofol during total i.v. anesthesia.