RESUMO
BACKGROUND: Clonidine and dexmedetomidine are alpha-2 agonists with beneficial effect on the hemodynamic response to laryngoscopy and intubation. The present study was designed to evaluate and compare the efficacy of intravenous clonidine 1 µg/kg, and dexmedetomidine in doses of 0.5 µg/kg and 1 µg/kg, for blunting the hemodynamic changes during laryngoscopy and intubation. METHOD: Adult patients of ASA physical grade I/II scheduled for surgery under general anaesthesia with endotracheal tube were randomly divided into three groups using a computer generated random number table, each group receiving one of the following drugs prior to induction of anaesthesia, by a blinded anaesthesiologist in a volume of 100 mL infused intravenously over 20 minutes: clonidine 1 µg/kg, or dexmedetomidine 0.5 µg/kg, or dexmedetomidine 1 µg/kg. General anaesthesia was induced using standard technique and intubations performed by same anaesthesiologist. Heart rate and mean blood pressure were recorded in pre-operative room (baseline) and again at 1 minute, 3 minutes, 5 minutes and 10 minutes after intubation. An increase in heart rate and/or mean blood pressure by >20% above baseline values during observation period was taken to indicate a positive intubation response. RESULTS: The incidence of intubation response was similar in all three groups (P>.05). The number of patients developing hypotension was significantly higher in group receiving dexmedetomidine1µg/kg group (P<.005) as compared to other two groups. Both the groups receiving dexmedetomidine had higher number of patients developing bradycardia as compared to patients receiving clonidine. DISCUSSION & CONCLUSION: Dexmedetomidine 0.5 µg/kg, 1 µg/kg and clonidine 1 µg/kg attenuate the laryngoscopy and intubation response but Clonidine 1 µg/kg was associated with lesser side effects.