Intravenous lidocaine infusion as a component of multimodal analgesia for colorectal surgery—measurement of plasma levels

Abstract

Background: Growing evidence suggests that intravenous lidocaine as a component of multimodal analgesia improves recovery after major colorectal surgery. There is little published data regarding ideal dosing and target plasma concentration in this context, and we wanted to establish our dosing schedule was safe by measuring blood levels of lidocaine. Methods: We measured the plasma lidocaine concentration of 32 patients at 30 min, 6 h and 12 h after starting intravenous lidocaine infusion for analgesia after major colorectal surgery. Patients received a bolus of 1.5 mg kg −1 over 20 min at the time of induction of anaesthesia. This was followed by a continuous infusion of 2% w/v lidocaine at 3 ml hr −1 (60 mg hr −1) for patients weighing up to 70 kg and 6 ml hr −1 (120 mg hr −1) for patients weighing over 70 kg, using actual body weight.