title: Intraperitoneal Instillation of Lidocaine Improves Postoperative Analgesia at Cesarean Delivery: A Randomized, Double-Blind, Placebo-Controlled Trial.
abstract: Cesarean delivery is a commonly performed procedure worldwide. Despite improvements in balanced multimodal analgesia, there remains a proportion of women for whom postoperative pain relief and patient satisfaction are still inadequate. Intraperitoneal instillation of local anesthetic has been shown to be effective in reducing postoperative pain after abdominal surgery. We sought to investigate the effect of intraperitoneal instillation of lidocaine on postcesarean delivery pain as part of a multimodal analgesia regimen.
  
  
  
  We studied women scheduled for elective cesarean delivery under spinal anesthesia. Spinal anesthesia was performed with 0.75% hyperbaric bupivacaine, fentanyl, and morphine. At the end of the cesarean delivery, immediately before parietal peritoneum or fascia closure, patients were randomized to receive either lidocaine (20 mL 2% lidocaine with epinephrine) or placebo (20 mL normal saline) instilled into the peritoneal cavity. The primary outcome was pain score on movement at 24 hours. Secondary outcomes were pain score at rest and on movement at 2, 24, and 48 hours; maternal satisfaction score; analgesic consumption; incidence of nausea, vomiting, and itching; and return of bowel function.
  
  
  
  Two hundred four women were recruited. Baseline characteristics were similar between the lidocaine and placebo groups. Pain scores at 24 hours postcesarean delivery on movement (parameter estimate 0.02 [95% confidence interval {CI} -0.14 to 0.18]; P = .823) and at rest (parameter estimate 0.00 [95% CI -0.32 to 0.33]; P = .986) were similar in both groups. Pain scores at 2 hours postcesarean delivery on movement (parameter estimate -0.58 [95% CI -0.90 to -0.26]; P = .001) and at rest (parameter estimate -1.00 [95% CI -1.57 to -0.43]; P = .001) were lower in the lidocaine group. Subgroup analysis of patients with peritoneum closure revealed significantly lower pain scores at 24 hours on movement (parameter estimate -0.33 [95% CI -0.64 to -0.03]; P = .032) in the lidocaine group. The number of women requesting postoperative opioids for breakthrough pain was significantly lower in the lidocaine group compared with that of the placebo (40 [40%] vs 61 [65%], respectively, relative risk 0.59 [95% CI 0.43-0.81]; P = 0.001).
  
  
  
  The use of intraperitoneal instillation of lidocaine improves early postoperative pain management after cesarean delivery. Furthermore, it reduces the number of women requesting systemic opioids in the immediate postpartum period. Women undergoing peritoneal closure may particularly benefit from this intervention.
authors.affiliation: From the Departments of *Anesthesia and Pain Management and †Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada; and Departments of ‡Laboratory Medicine and Pathobiology and §Public Health Sciences, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Ruchira
authors.initials: R
authors.lastname: Patel
authors.forename: Jose C A
authors.initials: JC
authors.lastname: Carvalho
authors.forename: Kristi
authors.initials: K
authors.lastname: Downey
authors.forename: Marcelo
authors.initials: M
authors.lastname: Kanczuk
authors.forename: Paul
authors.initials: P
authors.lastname: Bernstein
authors.forename: Naveed
authors.initials: N
authors.lastname: Siddiqui
mesh_terms: D000328:Adult; D000775:Anesthesia, Spinal; D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000627:therapeutic use*; D002585:Cesarean Section / Q000379:methods*; D004311:Double-Blind Method; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage; D006801:Humans; D007274:Injections, Intraperitoneal; D008012:Lidocaine / Q000008:administration & dosage* / Q000627:therapeutic use*; D009020:Morphine / Q000008:administration & dosage; D010147:Pain Measurement; D010149:Postoperative Pain / Q000517:prevention & control*; D020250:Postoperative Nausea and Vomiting / Q000453:epidemiology; D011247:Pregnancy
chemical_list: D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local; D009020:Morphine; D008012:Lidocaine; D005283:Fentanyl