Intraabdominal Chloroprocaine During Cesarean Delivery for Pain Control

Objective The objective of this study is to test the hypothesis that instillation of intra-abdominal chloroprocaine during cesarean deliveries is associated with decreased postoperative pain and nausea compared to placebo, without increasing intraoperative and postoperative complications. Methods The investigators plan to randomize about 150 women undergoing primary and repeat cesarean deliveries to intra-abdominal chloroprocaine versus placebo prior to abdominal closure. Women will be excluded if they have ascertained or presumptive hypersensitivity to the ester type and major anesthetics; if they have chronic pelvic pain or if they refuse to participate in the study. The investigators' primary outcome measure will be postoperative pain as measured by visual analogue scale (VAS) at 1 hour after skin closure. Secondary outcomes will include objective pain as measured by VAS at 2, 6, 24 and 48 hours at rest and during mobilization, adverse effects of chloroprocaine (gastrointestinal side effects, pruritus), concomitant analgesic requirement, hospital readmissions and length of hospital stay. Analysis will follow the intention-to-treat principle. The investigators will also be studying the concentration/effect (PKPD) relationship of chloroprocaine use for pain control in the postpartum period. The time courses of the plasma concentrations of chloroprocaine will be analyzed with mixed effects pharmacokinetic-pharmacodynamic (PKPD).