Efficacy of oropharyngeal lidocaine instillation on hemodynamic responses to orotracheal intubation.

Study Objective: To determine whether oropharyngeal instillation of lidocaine after anesthetic induction modifies the hemodynamic response to intubation.

Design: Prospective, randomized, double-blind, placebo-controlled study.

Setting: Operating room of a university hospital.

Patients: 56 ASA physical status I and II adult patients scheduled for elective surgery requiring orotracheal intubation and general anesthesia.

Interventions: Patients were randomized to receive oropharyngeal instillation with either 5 mL 2% lidocaine (n = 28, lidocaine group) or 5 mL normal saline (n = 28, control group) 45 seconds after anesthetic induction bolus. Orotracheal intubation was attempted three minutes later.

Measurements: Systolic (SBP), diastolic (DBP), mean arterial pressure (MAP), and heart rate (HR) were recorded at baseline, just before intubation, and for three minutes postintubation at one-minute intervals. Occurrence of adverse events such as arrhythmias, ischemic changes in electrocardiography, and bronchospasm after intubation were also documented.

Main Results: All postintubation values of SBP, DBP, MAP, and HR were significantly lower in the lidocaine group than the control group (P < 0.01). In both groups, postintubation HRs were significantly higher than baseline values (P < 0.05). More patients (P < 0.001) became hypertensive postintubation in the control group (14/28, 50%) than the lidocaine group (2/28, 7%).

Conclusion: Oropharyngeal instillation of lidocaine for three minutes before intubation attenuates the cardiovascular responses to intubation.