Effets de la lidocaïne sur la circulation artérielle et veineuse des membres chez l'homme

Abstract

The effects of intravenous lidocaine on limb arteries and veins were investigated in a placebo-controlled study. Seven young healthy volunteers, 23 to 28 — years — old, were included. Electrocardiogram, arterial pressure and arm and leg blood flows were recorded continuously. Systolic and diastolic blood pressures were measured in the left arm by finger photoplethysmography. Limb blood flow and the limb venous system were studied by venous occlusive plethysmography. The venous parameters studied were venous tone, lowest closing pressure, venous volume at 30 mmHg, and venous distensibility. After an initial bolus of 1.5 mg · kg −1 lidocaine had been given, 30, and then 60, μg · kg −1 · min −1 were given for one hour each. Plasma noradrenaline and serum lidocaine titres were measured before giving the lidocaine, and at the end of each one hour period. Placebo consisted in a two hour infusion of 0.25 ml · min −1 normal saline. Lidocaine titres were 1.64 ± 0.40 μg · ml −1 after one hour, and 2.55 ± 0.69 μg · ml −1 after two hours. Lidocaine increased vascular resistances in both the forearm (+ 81 % to + 93 %) and the calf (+ 38 % to + 57 %). There was a concomitant increase in mean arterial blood pressure (+ 21 % to + 28 %) without any change in heart rate. There was a significant dose-dependent increase in plasma noradrenaline levels during the second period of the lidocaine infusion with respect to the preinfusion period and the same period during the placebo infusion. Venous capacitance measured before any infusion had been started was greater in the leg than in the arm. Lidocaine induced a progressive increase in forearm venous tone, which became significant during the period of higher infusion rate. There wasn't any change in calf venous tone. It would therefore seem that the arterial and venous effects of lidocaine which have been reported may be due to an increase in adrenergic tone. The vascular effects of therapeutic serum levels of lidocaine may contribute to the good cardiovascular tolerance of this drug, both as local anaesthetic agent, and as antiarrhythmic drug.