Comparative effects of oral clonidine and intravenous esmolol in attenuating the hemodynamic response to epinephrine injection

Study Objective: To evaluate oral clonidine and intravenous esmolol in blun ting hemodynamic changes associated with intranasal injection of an epineph rine-containing local anesthetic solution during general anesthesia. Design: Prospective, randomized, double-blind placebo-controlled study. Setting: University Medical Center. Patients: 61 consenting ASA physical status I and II outpatients undergoing endoscopic sinus and septoplasty surgery with general anesthesia Interventions: All patients were assigned to receive either a placebo (P) t ablet or a similar-appearing tablet containing either clonidine 0.2 mg (C2) or 0.4 mg (C4) orally 1 hour prior to entering the operating room. Prior t o the intranasal injection of epinephrine, patients were administered eithe r saline, 0.03 ml . kg(-1) followed by an infusion of 0.016 ml . kg(-1) . m in(-1), or esmolol (E) 300 mu g kg(-1) followed by a continuous infusion of 160 mu g . kg(-1) . min(-1). Measurements and Main Results: Arterial blood pressure and heart rate (HR) values were recorded preoperatively, immediately before induction of anesth esia, and at 1-minute intervals after induction of anesthesia until 15 minu tes after injection of an epinephrine-containing solution. Level of sedatio n was assessed using a linear visual analog scale (VAS) prior to oral preme dication, immediately before induction of anesthesia, and 30 minutes after anesthesia. There were no significant differences in sedation scores among the four treatment groups. HR following injection of epinephrine-containing solution was significantly less in the C2, C4, and E groups than the place bo group. Compared to P and E treatment groups, MAP values were significant ly lower in the C4 treatment group. Conclusion: In this healthy, young; nonsmoking outpatient population, preme dication with oral clonidine, 0.2 to 0.4 mg; was effective in blunting the acute hemodynamic changes associated with injection of an epinephrine-conta ining local anesthetic solution during endoscopic sinus or septoplasty surg ery. (C) 1999 by Elsevier Science Inc.