Impact of Intravenous Lidocaine During Colorectal Surgery on Pain and Immune Functions

lidocaine 2% will be used for induction (1 syringe of 5 ml, administered dose of 1.5 mg / kg) and for intra-operative infusion (1 syringe of 30 ml, infusion dose of 1.5 mg / kg / h). Lidocaine syringes and placebo will be prepared on a blinded manner so that the investigating anesthesiologist in charge of the patient in the operating room, as well as the respiratory therapist and the recovery room nurse and the floors do not know what the patient received during the anesthesia (whether IVL or placebo).

Group Control will receive (double blinded) an infusion of saline at the same volume and regimen than the lidocaine 2% group (IVL).