The Effects of Continuous Infusion of Esmolol on the Hemodynamic Changes following Endotracheal Intubation in Patients with Hypertension

Kim, Nam Joong; Kong, Myoung Hoon; Chang, Seong Ho

Abstract

Laryngoscopy and endotracheal intubation are potent stimuli that increase heart rate and blood pressure. These transient stress responses are probably not harmful in healthy individuals. However hypertensive patients are more prone to have significant increase in heart rate and blood pressure whether they have been treated beforehand or not and these responses also can lead to fstal complications. A randomized double-blind study was csrried out on 40 ASA physical status II-III adult elective surgical patients with hypertension to assess the effects of continuous intravenous infusion of esmolol, ultrashortacting cardioselective beta blocker, on hemodynamic responses to laryngoscopy and endotracheal intubation. Patients received a continuous infusion of esmolol(500mcg/kg/min for 1 minute, followed by 200mcg/kg/min for 12minutes) or an equal volume of saline before and throughout the induction periods of anesthesia. Using noninvasive automatic blood pressure monitor, blood pressure( systolic, diastolic and mean arterial pressure) and heart rate were measured at 6 points: 1) as the control value, on arrival to operating room, 2) just after IV loading dose of saline or esmolol, 3) just after IV thiopental, 4) 1 minute after intuhation, 5) 3 minutes after intubation, and 6) 5 minutes after intubation. The rate-pressure product was calculated in each time. During this study, anesthesia was maintained with enflursne-N2O-O2 vecuronium and controlled ventilstion. In patients given esmolol, systolic pressure, diasolic pressure, mean arterial pressure, heart rate, and rate pressure product at 1 minute, 3 minutes, 5 minutes after intubation were less increased than control group. And the heart rste response was more effectively blunted than the blood pressure response. The continuous infusion of esmolol can blunt hemodynamic changes caused by laryngoscopy and endotracheal intubation in hypertensive patients, yet it is needed to find out the optimal dosage of esmolol for complete blocking of the sympathetic response without the adverse effects.