Dexmedetomidine as an adjunct to anaesthetic induction to attenuate haemodynamic responses to Endotracheal Intubation

Introduction: The hemodynamic responses to endotracheal intubation (EI) may impose myocardial ischemia, infarction (MI); arrhythmias or precipitate cardiac failure. Dexmedetomidine, which is a D-isomer of medetomidine is more specific for alpha 2 adrenergic receptor and shorter acting than clonidine. As studies to explore the property of dexmedetomodine for attenuation of haemodynamic responses to EI are only few, this study was an attempt to assess the efficacy and safety of dexmedetomidine for the same. Aim and Objectives: To assess the efficacy of a single preoperative dose of intravenous dexmedetomidine in attenuating the haemodynamic responses to EI. Materials and Method: The study design was prospective, interventional randomised placebo controlled clinical trial. Each and every patient who fulfilled the eligibility criteria was randomly assigned to one of the two groups, Group C (Control) or Group D (Dexmedetomidine), using a computer generated random number table. Participants of group C received 20 ml of normal saline over 15 minutes and of group D received dexmedetomidine 0.5µg/kg diluted in normal saline to make 20 ml over 15 minutes through a syringe pump. Results: There was statistically significant rise in the mean heart rate in Group C‚ during EI from 82.82 ± 13.37 to 115.86 ± 13.12 (p<0.001). In Group D‚ there was a decrease in mean heart rate at preinduction from basal value of 86.74 ± 15.37 to 76.00 ± 14.77 (p<0.001). The mean heart rate during EI (I) and also at one minute after intubation came to near basal level 87.82 ± 15.41 (p>0.05). Similar results were for systolic arterial pressure, diastolic arterial pressure, mean arterial pressure and rate pressure product. Conclusion: From the present study‚ it is concluded that pretreatment with dexmedetomidine 0.5µg/kg attenuated the sympathoadrenal response to laryngoscopy and endotracheal intubation effectively‚ but could not obtund it completely. It was also inferred that tachycardiac response was better attenuated than pressure response.