A Comparison of the Effects of Esmolol and Dexmedetomidine on the Clinical Course and Cost for Controlled Hypotensive Anaesthesia.

OBJECTIVE

To compare the effects of esmolol (β-blocker) and dexmedetomidine (α-2-agonist) on patients' clinical course and cost of application of controlled hypotension during middle-ear surgery.

METHODS

Fifty ASA I-II patients scheduled for tympanomastoidectomy were enrolled in the study and were randomized into two groups. Bispectral Index (BIS) and neuromuscular monitoring (TOF GUARD-SX) were applied to all patients. In group E (n=25), 0.5 mg kg(-1) min(-1) esmolol was infused over 1 min before induction and titrated over a range of 10-200 μg kg(-1) min(-1); in group D (n=25), 0.5 μg kg(-1) dexmedetomidine was infused over 10 minutes before induction, and then titrated over a range of 0.2-0.7 μg kg(-1) hr(-1) to maintain mean arterial pressure (MAP) between 55 and 65 mmHg and BIS 40-50 after induction. In both groups, 0.25 μg kg(-1) min(-1) remifentanil infusion was used for anaesthesia maintenance. Maintaining end-tidal CO2 (EtCO2) at 35-40, using 1 MAC sevoflurane in 50% O2-air mixture, mechanical ventilation was started. The effects of both agents on hemodynamic conditions [(heart rate (HR), mean arterial pressure (MAP)], neuromuscular blockage [onset of action (OA), duration of clinical action (DCA), recovery index (RI)], amount of bleeding, surgeon satisfaction, and total dexmedetomidine and esmolol doses used during the intervention were recorded and costs were compared between the groups.

RESULTS

No significant difference was present in hemodynamic conditions, bleeding scores or surgeon satisfaction between groups. Although OA was similar in both groups, DCA and RI were significantly higher in group D. Cost was significantly higher with esmolol than dexmedetomidine.

CONCLUSION

We conclude that although both agents are feasible in inducing hypotensive anaesthesia, while neuromuscular block time prolonged by using dexmedetomidine, higher costs were observed with esmolol.