Intravenous lidocaine does not affect the anesthetic depth during rapid sequence induction and intubation as assessed by Bispectral Index monitoring: a randomized double blind study

Abstract

Introduction: We investigated the impact of intravenous lidocaine on anesthetic depth, as assessed by Bispectral Index score (BIS), and hemodynamic responses to rapid sequence induction/intubation.

Material and methods: Eighty-four surgical patients with risk factors for regurgitation/aspiration were randomized to receive either lidocaine 1.5 mg/kg or normal saline in a double-blind fashion. Propofol 2 mg/kg, lidocaine or normal saline, followed by rocuronium 1 mg/kg were administered intravenously and trachea was intubated under cricoid pressure application. The BIS scores were recorded before induction of anesthesia, immediately after, at 30 s and 1 min after rocuronium injection and every 30 s after intubation, for 10 min. Systolic/diastolic blood pressure and heart rate were measured before induction, immediately after and at 1 min following rocuronium administration, and every minute for 10 min after intubation.

Results: Data from 78 patients were analyzed. Demograpic characteristics did not differ between the study groups. A total of 24 BIS scores were recorded for each patient. No difference was found in BIS values between lidocaine and control groups at any time point (F = 2.936, p = 0.91). Also no difference was detected in heart rate, systolic and diastolic blood pressure at any time point of the study period between the two groups (F = 0.063, p = 0.80, F = 0.007, p = 0.93, F = 0.435, p = 0.51 respectively). No episodes of significant bradycardia occurred and none of the patients reported awareness/recall of the procedure.

Conclusions: Lidocaine 1.5 mg/kg given intravenously during rapid sequence induction does not affect BIS values, or blunt the hemodymanic response to laryngoscopy and intubation.

Keywords: anesthetic depth; bispectral index; lidocaine; rapid sequence anesthesia.

Figure 1

Bispectral Index values at the time points of measurement, in lidocaine (L) and control (C) groups. Values are mean ± SD Time points of measurements: bef: before induction of anesthesia, 1 – immediately after rocuronium, 2 – 30 s after rocuronium, 3 – 1 min after rocuronium – just before laryngoscopy, 4 – 30 s after cuff inflation, 5–22 – every 30 s, 23 – 10 min after cuff inflation