Does Intraperitoneal Instillation of Lidocaine at Cesarean Delivery Improve Postoperative Analgesia?

The instillation of local anesthetic into the peritoneum has been found to be safe and effective in reducing postoperative pain and morphine consumption after abdominal surgery. A review of studies reporting serum levels of local anesthetic after intraperitoneal delivery found no cases of clinical toxicity in any of the trials. The studies in this meta-analysis did not include post-cesarean delivery pain and there is a lack of data to support the use of intraperitoneal local anesthetic after cesarean section.

The purpose of this study is to assess the efficacy of intraperitoneal lidocaine on postoperative pain scores after cesarean delivery. This study will compare a 20ml solution of lidocaine (400mg) with epinephrine 5mcg/ml versus normal saline (placebo) instilled into the peritoneum at the end of surgery in women undergoing cesarean delivery. The investigators hypothesize that intraperitoneal lidocaine will result in lower pain scores, reduce opioid consumption and opioid related side effects, and higher maternal satisfaction after cesarean delivery.

Postoperative pain after cesarean delivery can have a significant negative impact on the mother's ability to care for her newborn and lead to complications such as thromboembolism, chronic pain, and depression. Postoperative analgesia for cesarean delivery has undergone remarkable improvement and is currently based on a multimodal approach to improve pain control and reduce the systemic complications of opiates. Despite this some patients still experience moderate to severe pain after cesarean delivery, and further strategies to improve analgesia and postoperative recovery are warranted.

The use of intraperitoneal local anesthetics to reduce postoperative pain has been studied in a variety of surgical settings, such as hysterectomy, laparoscopic cholecystectomy and minor laparoscopic gynecological procedures. These studies have compared different local anesthetics and the timing of local anesthetic delivery in relation to surgery, for example pre-procedure, at the end of surgery or via continuous catheter infusion. Intraperitoneal lidocaine at the end of surgery was associated with lower postoperative pain scores after total abdominal hysterectomy (200mg lidocaine) and laparoscopic cholecystectomy (400mg lidocaine). There is a large growing body of evidence to support the use of intraperitoneal local anesthetic to reduce postoperative pain. However, there is a lack of data to support its use in postcesarean delivery pain. The investigators found one study reporting a decreased incidence of postoperative pain following intraperitoneal lidocaine instillation at the end of cesarean delivery, in which the parietal peritoneum had been sutured.

The purpose of this study is to evaluate the efficacy of intraperitoneal lidocaine 400mg instillation at the end of cesarean delivery on maternal pain scores and satisfaction, in the context of a multimodal analgesic regimen inclusive of intrathecal opioids and systemic NSAIDs, acetaminophen and opioids. The investigators hypothesize that intraperitoneal lidocaine will decrease VAS pain scores, reduce opioid consumption and opioid related side effects, and increase maternal satisfaction after cesarean delivery.

Eligibility Criteria:
Inclusion Criteria:

* ASA I or II patients
* 18-50 years of age
* Term pregnancy
* Singleton pregnancy
* Spinal anesthetic
* Pfannenstiel incision
* Patients who have given pre-operative informed written consent

Exclusion Criteria:

* Patients who refuse or are unable to give consent
* ASA \>2
* Multiple gestation
* Chronic pain
* BMI \>40
* Contraindication to acetaminophen or non-steroidal anti-inflammatory drugs