Effect of dexmedetomidine bolus dose on isoflurane consumption in surgical patients under general anesthesia

Various adjuvants have been introduced to decrease the dose of volatile agents and their side effects. Dexmedetomidine a potent alpha-2 adrenoreceptor agonist is one such agent. Our objective is to assess the effect of preanesthetic dexmedetomidine on isoflurane consumption and its effect on intraoperative hemodynamic stability and recovery profile.

This prospective, randomized controlled, double-blind study was done in a tertiary care hospital.

One hundred patients were randomly allocated into two groups. Group 1 received saline infusion and Group 2 received dexmedetomidine infusion in a dose of 1 μg/kg over 10 min given 15 min before induction. Vital parameters and bispectral index (BIS) values were noted throughout the surgery. Patients were induced and intubated as per the standard protocol and maintained with N₂O: O₂ = 1:1 mixture at 2 L/min and isoflurane concentration adjusted to achieve BIS values of 45-60. Demographic profile, hemodynamic variables, total isoflurane consumption, and recovery profile data were collected.

Independent t-test and Mann-Whitney U-test were used to compare the average anesthetic consumption, hemodynamics, and recovery profile between two groups.

End-tidal concentration and total isoflurane consumption in Group 2 were 0.56 ± 0.11 and 10.69 ± 3.01 mL, respectively, with P < 0.001 which was statistically significant compared to Group 1 which were 0.76 ± 0.14 and 13.76 ± 3.84 mL. Postintubation and intraoperative mean arterial pressure values were significantly lower in dexmedetomidine group with P < 0.001.

Preanesthetic bolus dose of dexmedetomidine is a useful adjuvant to reduce isoflurane consumption.