Liposomal Bupivacaine at Cesarean Delivery to Decrease Post-operative Pain

This study is a randomized controlled trial. A total of 80 patients will be randomized 1:1 to intervention (liposomal bupivacaine) versus control (placebo solution). The planned intervention is the infiltration of liposomal bupivacaine (or control) at the time of fascial closure at a Pfannenstiel incision, after the delivery of the infant and repair of the hysterotomy. The procedure to instill the drug is as follows: Once the patient is in the operating room, neuraxial anesthesia will be administered per routine practice. A Pfannenstiel skin incision will be made. The usual cesarean delivery procedure will be performed at the discretion of the surgeon. Once the surgical team is about to begin fascial closure, the study drug will then be infiltrated by a member of the study team, with 50% of the study solution in subcutaneous space and 50% in the fascial plane, taking care to evenly spread the drug in the superior and inferior aspects of the incision. For the fascial infiltration, liposomal bupivacaine will be preferentially infiltrated laterally. The remainder of the cesarean delivery will proceed according to the usual fashion. At any point in the cesarean delivery, the surgeon may chose to administer or withhold ketorolac. Post-operative pain management will be: intrathecal morphine, scheduled ketorolac 30mg IV x 24h followed by ibuprofen 600mg q6h x 24h, scheduled Tylenol 650mg q6h x 48h, and prn oxycodone 5-10mg q4h. This is the current pain management protocol for postoperative women after cesarean delivery. If Tylenol or NSAIDs are contraindicated, either due to the discretion of the clinical team or pre-existing patient contraindication, these will not be administered but are not a reason for study exclusion. The investigators plan to enroll 80 patients into this pilot study, 40 per group. This sample size is based on prior data among women who had a cesarean delivery at this institution, and were asked to report their pain scores with activity at 48- and 72- hours after operation. With this sample size, the investigators have 80% power to detect a 1.5 point difference in pain at 48 hours, and 90% power to detect a 1.5 point difference in pain at 72 hours, and account for any protocol violations or loss to follow-up.