Effect of systemic lidocaine infusion on train-of-four ratios during recovery from general anesthesia

IntroductionIn spite of introduction of intermediate-acting neuromuscular blocking drugs (NMBDs), incidence of postoperative residual muscle weakness is still high. The aim of this trial is to study the effect of systemic lidocaine infusion on intraoperative consumption of rocuronium and TOF ratios at extubation and on arrival to postanesthesia care unit (PACU).MethodsForty-six ASA I–III patients aged 16–60 yr were randomly allocated into two groups: lidocaine (L) group (n = 23) and control (C) group (n = 23). After induction of standard endotracheal general anesthesia with fentanyl, propofol and rocuronium, patients of group L were given i.v. lidocaine bolus (1.5 mg kg−1) followed by continuous infusion (1.5 mg kg−1 h−1) till time of endotracheal extubation while patients in group C were given equal volumes of normal saline. Rocuronium was titrated based on clinical signs. On conclusion of surgery, neostigmine was given to reverse the effects of rocuronium if TOF count was two or more. Immediately before extubation, TOF ratio was measured and recorded and considered the primary outcome.ResultsThere were no significant differences between the two study groups regarding intraoperative fentanyl doses or core temperature at the end of surgery. End-tidal sevoflurane concentrations were significantly lower in group L than in group P (P < 0.01). The dose of rocuronium was significantly less in group L than in group C (P = 0.001). Train-of four ratios were significantly higher in group L than in group C either before extubation (P < 0.001) or on arrival to PACU (P = 0.001).ConclusionThe current study shows that intraoperative use of i.v. lidocaine infusion in generally anesthetized patients can result in higher TOF ratios at time of extubation and on arrival to PACU when rocuronium was given based on clinical signs.