COMPARISON OF THREE DIFFERENT DOSES OF REMIFENTANIL TO SUPPRESS PRESSOR RESPONSE DURING LARYNGOSCOPY AND INTUBATION

Abstract

Objective:  Laryngoscopy and endotracheal intubation violate the patient's protective airway reflexes and induce a transient but marked sympathetic pressor response characterized by tachycardia and hypertension. The aim of this randomized prospective study was to evaluate and identify the optimal bolus dose among three different doses of remifentanil  (0.5 μg/kg, 1 μg/kg, and 2 μg/kg) to suppress this acute cardiovascular stress response during general anaesthesia induction. Patients And Methods:  A cohort of 90 patients of ASA physical status I and II, aged 18 to 65 years, scheduled for elective general surgical procedures under general anaesthesia, were enrolled and randomly assigned to three parallel groups of 30 patients each: Group R1 received remifentanil 0.5 μg/kg, Group R2 received 1 μg/kg, and Group R3 received 2 μg/kg. Anaesthesia was induced with intravenous propofol  2mg/kg, and muscle relaxation was achieved with succinyl choline 1 mg/kg. Hemodynamic variables, including heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP), were closely tracked from baseline up to 60 minutes post-intubation. Side effects and complications were documented. Results:  Following laryngoscopy and tracheal intubation, a highly significant increase in heart rate and arterial pressures occurred in Group R1 (0.5 μg/kg), confirming inadequate protection against the sympathetic surge at this dose level. Groups R2 (1 μg/kg) and R3 (2 μg/kg) both demonstrated excellent suppression of the pressor response. However, Group R3 was associated with a significantly higher incidence of intraoperative hypotension (23.33%) and clinically significant bradycardia(13.33%) compared to Groups R1 and R2 (p  <  0.05).  Perioperative complications  remained minimal and statistically comparable across all groups. Conclusions:  Remifentanil administered as a bolus dose of 1 μg/kg provides the most favorable clinical balance, offering optimal and highly effective attenuation of the airway-circulatory pressor reflex while maintaining hemodynamic stability without inducing excessive cardiovascular depression or bradycardia.