Efficacy of oropharyngeal lidocaine instillation on hemodynamic responses to endotracheal intubation

Purpose: This study attempts to determine whether oropharyngeal instillation of 5mL of 2% lidocaine for 3 min before intubation modifies changes in heart rate (HR) and blood pressure (BP) responses to the stimulation.

Materials and methods: Fifty-six surgical patients were randomized to receive oropharyngeal instillation with either 5 mL of 2% lidocaine (lidocaine group) or 5 mL of normal saline (control group) 45 s after induction bolus. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), and HR were recorded every min thereafter for 6 min. Laryngoscopy and intubation was attempted at 3 min after intervention. The 1-min postintubation values of HR, SBP, DBP, and MBP between the groups, and their changes from baseline were compared as a priori using the unpaired t-test.

Results: The 1-min postintubation values of SBP, DBP, MBP, and HR were significantly lower in the lidocaine group as compared to the control group (P < 0.05). The differences in mean values of SBP, DBP, and MBP changes from baseline were significantly greater in the control group (P ≤ 0.001), while that of HR was not significant. More patients (P < 0.001) become hypertensive at 1-min postintubation in the control group than in the lidocaine group. No differences in tachycardia incidence were found.

Conclusion: We conclude that oropharyngeal administration of lidocaine before intubation attenuates the cardiovascular responses to the stimulation. It is a simple and effective method for achieving anesthesia of the upper airway and rendering induction smoother with respect to cardiovascular changes.