A Comparative Clinical Study of Oral Clonidine versus Intravenous Clonidine for Attenuation of Haemodynamic Response to Endotracheal Intubation

Background And Objectives: Laryngoscopy with or without tracheal intubation amounts to a highly noxious stimulus to the homeostasis of the patient. Many a times under lighter planes of anaesthesia it elicits a defence mechanism in the form of haemodynamic response to stress, which involves activation of adrenocortical system. This study was conducted to compare the effects of oral Clonidine and IV Clonidine premedication on haemodynamic response to laryngoscopy and endotracheal intubation. Method: One hundred normotensive patients between 18-45yrs of age (ASA Grade I & II) scheduled for elective surgery were sub-divided into two groups with 50 patients in each group. Group-I received oral Clonidine 4μg/kg and Group-II received intravenous Clonidine 3μg/kg 60 minutes and 15 minutes before induction respectively. Induction was done with inj Propofol 2mg/kg and inj Atracurium 0.5mg/kg or inj Vecuronium 0.1mg/kg. Heart rate(HR), Systolic blood pressure(SBP) , Diastolic blood pressure(DBP), Mean blood pressure(MBP) were recorded at preinduction, post-induction (pre-laryngoscopy) and post-laryngoscopy (1minutes, 3minutes, 5minutes, 10minutes & 15minutes). Results: Heart rate, Systolic blood pressure, Diastolic blood pressure, and Mean blood pressure increased by 3minutes post-laryngoscopy in both groups. But the response was significantly less in the IV Clonidine group as compared to the Oral group. All the variables returned towards baseline values by 10-15minutes postlaryngoscopy in either groups. Conclusion: IV Clonidine 3μg/kg premedication effectively blunted stress response to endotracheal intubation in ASA physical status I and II patients without causing adverse reactions. Oral Clonidine 4μ/kg was less effective in blunting haemodynamic stress response.