Intravenous lignocaine prior to intubation effect on rhythm and changes in heart rate and rate pressure product - abstract

ABSTRACT

Tracheal intubation is frequently associated with occurrence of cardiac dysrhythmias and is almost always accompanied by increases in systolic and diastolic blood pressure. In some instances, these cardiovascular changes may lead to disastrous complications. A prospective study was undertaken to evaluate the efficacy of intravenous lignocaine prior to intubation in blunting the cardiovascular responses to intubation in a West Indian population. Seventy-five clinically fit patients (age range 20 -40 years, mean 27.5) were included. They were divided into 3 groups as follows Group A received 1 mg/kg lignocaine hydrochloride as I.V. bolus dose 1 min prior to induction of anaesthesia. Group B - received 2mg/kg lignocaine, and Group C - No ligocaine (control). Parameters recorded were heart rate (HR), cardiac rhythm (ECG), systolic and diastolic bloodpressure (BP), and (heart) Rate - (systolic) pressure product (RPP). These were measured at the following times 1. Prior to induction of anaesthesia, 2. During laryngoscopy and intubation, 3 1 min following intubation and 4 5 mins following intubation. After the pre-induction parameters were recorded, lignocaine was given in 1 and 2 mg/kg doses in groups A & B patients. One minute following lignocaine, patients were anaesthetised using standard techique and the trachea was intubated. All parameters were again recorded, lignocaine was given in 1 and 2 mg/kg doses in groups A percent B patients. One minute following lignocaine, patients were anaesthetised using standard technique and the trachea was intubated. All parameters were again recorded at the stated times. Both the HRs and RPPs increased significantly in all the 3 groups following intubation. The increase in group B (2mg/kg) was significantly lower than in the control group. Group A patients (1mg/kg) did not show any consistent difference, statistically, compared to the control group. The incidence of dysrhythmias was 64 percent in the control group, 32 percent in group A patients (1mg/kg) and 12 percent in group B (2mg.kg). Seventy per cent of all dysrhythmias occurred at the time of laryngoscopy and intubation, consisting mainly of supra-ventricular and ventricular ectopics. Intravenous lignocaine prior to intubation decreases the incidence of dysrhythmias and also decreases the degree of rise in HRs and RPPs. Lignocaine at a dose of 2 mg/kg is better than a dose of 1 mg/kg (AU)