Effects of Esmolol on Hemodynamic Responses to Laryngoscopy and Tracheal Intubation in Normotensive Patients

Lee, Jung Koo; Kim, Jin Mo; Chung, Jung Kil; Cheun, Jae Kyu

Abstract

Laryngoscopy and endotracheal intubation undergoing general anesthesia cause hypertension and tachycardia with concomitant increases in plasma catecholamine concentration. These transient stress responses are greatly exaggerated in patients with hypertension and cardiovascular diseases and can lead to cardiac arrhythmia, pulmonary edema, cardiac failure and cerebral hemorrhage. Therefore, several attempts have been made to attenuate the hypertensive and tachycardiac responses, but none has been satisfactory. This study was made to alleviate the hemodynamic responses to tracheal intubation using ultra-short acting cardioselective beta-blocker, Esmolol. Following get informed consent in ASA physical status 1 and 2, 28 patients were randomly divided into two groups. Group 1(n=16), control group, and group 2(n=12), esmolol treatment group. Patients on alpha or beta-blockers or agonists were excluded from the study. 12 patients received an infusion of 500 mcg/kg/min esmolol loading dose for 3 min before induction with thiopental and 300 mcg/kg/min for maintenance for 6 additional minutes during the endotra- cheal intubation. The control patients, group 1(n=16), received 5% D/W infusion in place of esmolol with infusion pump. The patients received hydroxyzine 1 mg/kg, nalbuphine 0.1 mg/kg, and glycopyrroate 0.2 mg i. m. 60 minutes before anesthesia. Patients were induced with sodium thiopental 4-5 mg/kg until the disappearance of lid-refex. Succinylcholine 1.0 mg/kg i. v. was used to facilitate endotracheal intubation. As soon as relaxation was complete, laryngoscopy was initiated. After the completion of intubation, nitrous oxide/oxygen=2: 2 L/min with 0.5-1.5 % halothane or enflurane was administered. The blood pressure and heart rate were measured using noninvasive automatic blood pressure manometer Accutorr 1A (Datascope) for 30 minutes per l minute. Blood pressure and heart rate were evaluated at 6 key points; 1) baseline, 2) anesthetic induction, 3) tracheal intubation, 4) I minute postintubation, 5) 2 minutes postintu- bation, and 6) 3 minutes postintubation, Data were analyzed with paired t-tests within the groups. P<0.05 was considered significant. Esmolol infusion significantly prevented the increases in heart rate and rate pressure product caused by laryngoscopy and endotracheal intubation. Esmolol also moderated the increases in pressures. Esmolol infusion may offer an important role in patients in whom an increase in heart rate, blood pressure and/or rate pressure product should be avoided during the endotracheal intubation.