Effects of 2 mg.kg⁻¹ of intravenous lidocaine on the latency of two different doses of rocuronium and on the hemodynamic response to orotracheal intubation.

BACKGROUND AND OBJECTIVES Lidocaine potentiates the effects of neuromuscular blockers and attenuates the hemodynamic response to orotracheal intubation. The objective of the present study was to test the effects of lidocaine on the latency of two different doses of rocuronium and on the hemodynamic response to intubation. METHODS Eighty patients were distributed in 4 groups: Groups 1 and 2 received 0.6 mg.kg(-1) of rocuronium; patients in Group 2 also received 2 mg.kg(-1) of lidocaine before intubation. Patients in Groups 3 and 4 received 1.2 mg.kg(-1) of rocuronium; patients in Group 4 received additional 2 mg.kg(-1) of lidocaine. The latency of the neuromuscular blockade was measured by acceleromyography. Hemodynamic evaluation was performed at baseline, immediately before, and 1 minute after orotracheal intubation (OI). RESULTS Statistically significant differences were not observed between the latency from 0.6 mg.kg(-1) and 1.2 mg.kg(-1) of rocuronium in patients who received lidocaine before induction and those who did not. The latency in patients who received 0.6 mg.kg(-1) of rocuronium with lidocaine was statistically similar to that of those who received 1.2 mg.kg(-1) rocuronium independently of whether lidocaine was administered or not. Patients who did not receive lidocaine before induction showed the same increases in systolic, diastolic, and mean arterial pressure and heart rate after OI, which was not observed in those patients who received lidocaine. CONCLUSIONS Intravenous lidocaine before anesthetic induction was capable of attenuating the hemodynamic response associated to OI maneuvers, but it did not reduce the latency of the neuromuscular blockade produced by two different doses of rocuronium.