Intravenous lidocaine for attenuation of pressor response after endotracheal intubation. A randomized, double-blinded dose-finding study

Abstract

ABSTRACT Introduction Endotracheal intubation (ETI) is one of the commonly used maneuvers in the daily anesthetic practice, it is commonly associated with hemodynamic stimulation leading to marked tachycardia, hypertension, and myocardial ischemia. Aim and objectives In this study, we compared three doses of lidocaine for prophylaxis against pressor response of ETI. We hypothesized that the larger dose (2 mg/Kg) will be more effective for attenuation of the pressor response. Methods After randomization, post induction of anesthesia patients were categorized into three groups according to the dose of lidocaine: group A received 1 mg/Kg, group B received 1.5 mg/Kg, and group C received 2 mg/Kg. To achieve blinding, the study drug was prepared by a research assistant and was diluted to 10 mL in all groups. Heart rate measurement after 1 minute of lidocaine injection was carried out. Heart rate, cardiac output and stroke volume were continuously measured and were recorded every 30 seconds starting from baseline pre-induction reading till 5 minutes zafter ETI, systolic and diastolic blood pressure were measured at 1-minute intervals starting from baseline reading till 5-minute after ETI. Results Pressor response was lower in group C receiving 2 mg/Kg with P value = 0.021 defined by an increase in the heart rate, cardiac output, or systolic blood pressure by 20% or more which was evaluated after ETI continuously for 5 minutes. Conclusion Lidocaine in the dose of (2mg/Kg) is more effective than lower doses in attenuation of the pressor response of the ETI.