Lack of effect of intravenous lidocaine on hemodynamic responses to rapid sequence induction of general anesthesia: a double-blind controlled clinical trial.

A double-blind, randomized trial was conducted in 16 women aged 20-48 yr, to assess the effect of intravenous lidocaine on the circulatory responses to rapid sequence induction of general anesthesia. None of the patients suffered from heart or lung diseases, all were scheduled for hysterectomy, and all were premedicated with 0.3 mg/kg diazepam orally 2 hr beforehand. Induction, preceded by preoxygenation, included simultaneous injection of thiopental and succinylcholine, without starting manual ventilation until the airway was secured with the endotracheal tube. Two minutes before laryngoscopy and intubation half of the patients received lidocaine, 1.5 mg/kg, intravenously (IV). The other half received an equal volume of saline. Cuff blood pressure was measured repeatedly by an automatic recording device, and heart rate and left ventricular ejection fraction (LVEF) were monitored by a portable nonimaging nuclear probe. After laryngoscopy and intubation, mean blood pressure increased 46%, heart rate 57%, and the rate pressure product (RPP) 84% from control values in patients given lidocaine, compared to 45, 66, and 113%, respectively, in the saline group (P greater than 0.05). Pronounced, but similar decreases in LVEF were observed in the two groups, to 0.40 from 0.65 in the lidocaine group and to 0.41 from 0.65 in the saline group. In all patients, RPP reached a level considered potentially dangerous to patients with ischemic heart disease. We conclude that lidocaine, 1.5 mg/kg IV, 2 min prior to laryngoscopy and intubation does not prevent hemodynamic reactions evoked by rapid sequence induction.