Effects of Aerosolized and/or Intravenous Lidocaine on Hemodynamic Responses to Laryngoscopy and Intubation in Outpatients

Abstract

A randomized, double-blind study was carried out on 40 unpremedicated, ASA I-II adult surgical outpatients to assess the effects of aerosolized lidocaine, intravenous lidocaine, both, orneither, on circulatory responses to laryngoscopy and intubation. Lidocaine (4 mg/kg) or saline was given by nebulizer in the holding area beginning at −15 minutes. The patient underwent a standarized induction of anesthesia that included IV curare (3 mg) and O₂ by facemask at minute 2, followed by IV thiopental (5 mg/kg) and succinylcholine (1.5 mg/kg) at minute 5. Lidocaine (2 mg/kg) or saline was given by IV push at minute 4. Laryngoscopy was begun at 5 minutes and continued for 45 seconds before intubation. Heart rate and systolic, diastolic, and meanblood pressures were automatically recorded at 1-minute intervals from 0 to 11 minutes. The fourtreatment groups included: group 1, aerosolized and IV saline; group 2, aerosolized saline, IV lidocaine; group 3, aerosolized lidocaine, IV saline; and group 4, aerosolized and IV lidocaine. There were no differences among the four treatment groups (n = ten per group) in any of the fourhemodynamic variables before laryngoscopy and intubation. Within each group, after intubation all four hemodynamic variables increased significantly over the corresponding baseline values for that group. However, the maximum values attained after intubation did not differ significantly among the four treatment groups for any of the four hemodynamic variables, whether those maxima were expressed as absolute values or as a percentage of baseline. Having found no difference in the effects of aerosolized and/or intravenous lidocaine and saline placebo on hemodynamic response to laryngoscopy and intubation in adult surgical outpatients using a rigidly standardized protocol, it is recommended that such usage of lidocaine be abandoned.