Bispectral index-guided intraoperative sedation with dexmedetomidine and midazolam infusion in outpatient cataract surgery

Abstract

Background: This study aimed to evaluate the role of alfa-2 agonist infusion, with dexmedetomidine or midazolam, on hemodynamic and respiratory parameters while titrating the sedation level with the bispectral index (BIS) during cataract surgery.

Methods: Ninety consenting ASA class I-III patients who were electively undergoing cataract surgery were enrolled in the double blind study. A random infusion of 0.25 microg kg(-1) hr(-1) Dexmedetomidine (Group D), 25 microg kg(-1) hr(-1) midazolam (Group M), or saline for controls (Group C) was administered after mounting a BIS monitor and routine anesthetic care. The target BIS level was >85. An additional bolus dose in 1 mL increments of the study drug or cessation of the infusion was adjusted according to the BIS level. Changes in respiratory and vital parameters were noted and, in case of mild pain, 25 microg fentanyl was administered as a bolus. Pain and sedation were evaluated in the early postoperative period using visual analogue and four rating sedation scales.

Results: In Group D, heart rate decreased in the later periods of surgery (35-50 min) and in the early postoperative period (5(th) and 15(th) min). Dose adjustments were required in six and ten patients in Groups D and M, respectively. Pain scores were lower with dexmedetomidine infusion.

Conclusions: Dexmedetomidine infusion mildly decreased heart rate in the later periods of surgery with better pain scores in the postoperative period. Dexmedetomidine should be an alternative for intraoperative sedation in outpatient cataract surgery.