Electrocardiographic Assessment of a Continuous Infusion of Lidocaine in Sevoflurane-Anesthetized Dogs

Lidocaine is a local anesthetic widely used in veterinary medicine and can be administered intravenously as a continuous infusion during general anesthesia. In addition to its analgesic and anti-inflammatory properties, lidocaine has antiarrhythmic effects that may influence cardiac electrical activity during anesthetic procedures.

To evaluate whether continuous intravenous infusion of lidocaine in dogs anesthetized with sevoflurane alters electrocardiographic and hemodynamic variables.

Prospective clinical study.

Twenty healthy dogs.

Dogs were anesthetized with sevoflurane administered via face mask, followed by orotracheal intubation and anesthetic maintenance with the same agent. After stabilization of the anesthetic plane, baseline measurements were recorded. The animals were randomly allocated into two groups: control group (CG) and lidocaine group (LG). In the LG, lidocaine was administered as an intravenous bolus (2 mg/kg) followed by continuous infusion at a rate of 100 μg/kg/min. The CG received 0.9% saline solution at equivalent volumes and infusion rates. Evaluations were performed at baseline and at 20, 40, 60, and 80 min after the start of the infusion. The variables analyzed included heart rate (HR), systolic, mean, and diastolic arterial blood pressures (SBP, MAP, and DBP, respectively), and electrocardiographic variables such as P wave duration, PR interval, QRS complex duration, QT interval, and P wave and R wave amplitudes.

No significant differences were observed between groups or across time points for any of the evaluated variables.

Continuous intravenous infusion of lidocaine at the evaluated dose did not produce significant electrocardiographic or hemodynamic alterations in dogs anesthetized with sevoflurane under the conditions of this study, suggesting no detectable impact on cardiovascular function in this experimental setting.