[Lack of effect of i.v. lidocaine on cardiovascular responses to laryngoscopy and intubation]

Abstract

A randomized open study was carried out on 36, ASA I-II adult surgical patients to assess the effect of intravenous lidocaine and fentanyl on circulatory responses to laryngoscopy and intubation. The three treatment groups include: group L, intravenous lidocaine 1.5 mg.kg-1 2 minutes before laryngoscopy, group F, intravenous fentanyl 4 micrograms.kg-1, and group C, no treatment. Induction, preceded by preoxygenation was performed by intravenous vecuronium for precurarisation, followed by thiopental 4-5 micrograms.kg-1 and succinylcholine 1.5 mg.kg-1. Before induction of anesthesia, there were no significant differences among the three groups in mean arterial pressure (MAP), heart rate (HR) and rate pressure product (RPP). After laryngoscopy and intubation, the three hemodynamic variables increased significantly from control values in group L and group C. The maximum values attained after intubation did not differ significantly between the two groups for any of the variables. In group F, these hemodynamic variables showed no significant changes after laryngoscopy and intubation and were significantly less than those in group F and group C. Intubating conditions were better in the fentanyl group than in the lidocaine group.