Dexmedetomidine attenuates sympathoadrenal response to tracheal intubation and reduces perioperative anaesthetic requirement.

BACKGROUND: Dexmedetomidine, an α-2 adrenoreceptor agonist, is gaining popularity for its sympatholytic, sedative, anaesthetic sparing and haemodynamic stabilising properties without significant respiratory depression.

METHODS: We assessed the efficacy of dexmedetomidine in attenuating sympathoadrenal response to tracheal intubation and analysed reduction in intraoperative anaesthetic requirement. Sixty patients scheduled for elective surgery of more than 3 hours were randomly selected. Control group received isoflurane-opioid and study group received isoflurane-opioid-dexmedetomidine anaesthesia. Dexmedetomidine infusion in a dose of 1 μg/kg was given over 10 min before the induction of anaesthesia and was continued in a dose of 0.2-0.7 μg/kg/Hr until skin closure. All patients were induced with thiopentone, fentanyl and vecuronium. Haemodynamic variables were continuously recorded.

RESULTS: The need for thiopentone and isoflurane was decreased by 30% and 32%, respectively, in the dexmedetomidine group as compared to the control group. After tracheal intubation, maximal average increase was 8% in systolic and 11% in diastolic blood pressure in dexmedetomidine group, as compared to 40% and 25%, respectively, in the control group. Similarly, average increase in heart rate was 7% and 21% in the dexmedetomidine and control groups, respectively. Fentanyl requirement during the operation was 100±10 μg in the control group and 60±10 μg in the dexmedetomidine group.

CONCLUSION: Perioperative infusion of dexmedetomidine is effective in attenuating sympathoadrenal response to tracheal intubation. It has significant anaesthetic and opioid sparing effect.