The Effect of Clonidine Premedication on Blood Pressure and Heart Rate during Endotracheal Intubation

Abstract

Background : The endotracheal intubation for inhalational anesthesia induces hypertension and tachycardia and these hemodynamic changes cause many cardiovascular complications. Propofol has hemodynamic stability compared with thiopental sodium as an induction agent of general anesthesia. Clonidine, an 2-adrenergic receptor agonist, blunts hemodynamic changes when administered as premedicant. We evaluated the hemodynamic stability during endotracheal intubation after clonidine premedication and each induction with thiopental sodium or propofol. Methods : The 40 male and 40 female patients who scheduled for elective surgery, were randomly assigned in 4 groups (Group I, II, III and IV). In Group II and IV, the patients were administered 150 g of oral clonidine 90 minutes before induction of general anesthesia. Thiopental sodium was used as induction agents in Group I and II, propofol in Group III and IV. We measured systolic blood pressure, diastolic blood pressure, mean arterial pressure and heart rate at ward before administration of oral clonidine premedication (baseline value), before induction, after administration of induction agent, just after intubation, 1, 2, 3 and 5 minutes after endotracheal intubation. Results : The systolic, diastolic and mean arterial pressure and heart rate were increased significantly in all 4 groups (P＜0.05) when compared to baseline value of each group but lower in Group IV (P＜0.05) compared to Group I, II, III. Conclusion : Clonidine 150 g premedication and induction of general anesthesia with propofol blunts hemodynamic changes induced by endotracheal intubation. (Korean J Anesthesiol 1998; 35: 654∼661)