Comparative effects of lidocaine, esmolol, and nitroglycerin in modifying the hemodynamic response to laryngoscopy...

To compare the safety and efficacy of lidocaine, esmolol, and nitroglycerin in modifying the hemodynamic response to laryngoscopy and intubation.

Randomized, placebo-controlled, double-blind study.

University-affiliated VA medical center.

40 ASA physical status I and II patients undergoing electric surgery with general endotracheal anesthesia.

Anesthesia was induced with thiopental sodium 5 mg/kg, and intubation was facilitated with vecuronium 0.15 mg/kg. Isoflurane (0.5% to 1%) and 50% nitrous oxide in oxygen were used for maintenance of anesthesia. In addition, patients received one of the following four study drugs intravenously (i.v.) prior to laryngoscopy: Group 1 (control) = saline 5 ml; Group 2 = lidocaine 1.5 mg/kg; Group 3 = esmolol 1.4 mg/kg; Group 4 = nitroglycerin 2 micrograms/kg.

Mean arterial pressure (MAP) and heart rate (HR) were recorded every minute for 20 minutes following induction of anesthesia. Following laryngoscopy and intubation, MAP increased significantly in all four treatment groups (control 49% +/- 19%, lidocaine 55% +/- 26%, esmolol 25% +/- 11%, nitroglycerin 45% +/- 21%) compared with preinduction baseline values. In the esmolol-pretreated patients, the increase in HR was significantly lower (20% +/- 3%) compared with the nitroglycerin (37% +/- 8%), lidocaine (52% +/- 8%), and control (29% +/- 4%) groups.

Lidocaine 1.5 mg/kg i.v. and nitroglycerin 2 micrograms/kg i.v. were ineffective in controlling the acute hemodynamic response following laryngoscopy and intubation. Esmolol 1.4 mg/kg i.v. was significantly more effective than either lidocaine or nitroglycerin in controlling the HR response to laryngoscopy and intubation (p < 0.05). Esmolol also was significantly more effective than lidocaine in minimizing the increase in MAP (25% vs. 55%).