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.