Comparison of Perioperative Opioid Consumption Following Pectoral Nerve Block for Breast Cancer Surgery

After induction of general anesthesia with propofol, remifentanil and succinylcholine, the patients will be divided either in the pectoral block group or the control group (sham block). Both groups will receive the same perioperative and postoperative anesthetic protocol. The investigator in charge of the patient will leave the operative room right before the completion of the pectoral block (or the sham block) to preserve randomisation and the block will be performed by another investigator. The pectoral block is performed under ultrasound guidance with 10 cc of lidocaine 1% with epinephrine 1/400000 between the pectoralis major muscle and the pectoralis minor muscle and 20 cc of the same solution between the pectoralis minor muscle and the serratus anterior muscle at the third rib. Anesthesia will be maintained with sevoflurane for a bispectral (BIS) index between 45 and 60. Analgesia will be provided with a perfusion of remifentanil adjusted to maintain a mean arterial blood pressure (MAP) in the range of ± 10% of the basal MAP (mean of the last three MAPs obtained before surgical incision, under sevoflurane-only anesthesia). The total remifentanil consumption will be assessed and compared between the groups. The investigators believe that the pectoral nerve block will significantly reduce the intraoperative remifentanil consumption.