Clinical study to evaluate the role of preoperative dexmedetomidine in attenuation of hemodynamic response to direct laryngoscopy and tracheal intubation.

Objectives: Dexmedetomidine, an α2 agonist, has been evaluated for its hypnotic, analgesic, and anxiolytic properties in the intraoperative period and critical care setting. However, data on the effect of dexmedetomidine on attenuation of pressor response to direct laryngoscopy and tracheal intubation are limited. We studied the effect of a single preinduction intravenous dose of dexmedetomidine of 0.5 μg/kg on hemodynamic responses to tracheal intubation, and dose requirements of anesthetics for induction and their adverse effects.

Methods: Eighty adult patients scheduled for elective surgery under general anesthesia requiring tracheal intubation were included. Patients were randomized into two groups: dexmedetomidine and placebo (n = 40 each). The study drug was administered intravenously over a period of 10 minutes prior to induction. Direct laryngoscopy and endotracheal intubation were performed. Hemodynamic parameters, the total dose of propofol, and adverse effects were recorded during induction and postintubation periods for 15 minutes.

Results: The maximum percentage increase in the heart rate after intubation was 19.6% less in the dexmedetomidine group than that in the placebo group (12.96% vs. 32.57%). The maximum percentage increases in systolic blood pressure, diastolic blood pressure, and mean blood pressure after intubation were significantly lower in the dexmedetomidine group than in the placebo group (12.38% vs. 45.63%, 19.36% vs. 60.36%, and 15.34% vs. 50.33%, respectively). There was a significant reduction of the mean total dose of propofol required for induction, 1.04 mg/kg in the dexmedetomidine group versus 2.01 mg/kg in the placebo group (p < 0.001). No serious side effects or adverse reactions were observed in either group.

Conclusion: Administration of a single preinduction intravenous dose of dexmedetomidine of 0.5 μg/kg resulted in significant attenuation of the rise in the heart rate, systolic blood pressure, diastolic blood pressure, and mean blood pressure, until 5 minutes postintubation. It significantly reduced the dose requirements of propofol for induction and caused minimal side effects.