Slow recruitment of subjects

The investigators aim to assess the analgesic effect of a two-dose epidural morphine regimen for 2nd day post-cesarean pain, as part of a multimodal analgesia regimen, which includes scheduled Nonsteroidal anti-inflammatory drugs (NSAIDs). The investigators hypothesize that administration of a second dose of epidural morphine 3 mg, 24 hours after an initial intraoperative dose, will provide superior post-cesarean analgesia during the 2nd 24 hours after surgery, compared to a single epidural morphine dose regimen. The primary outcome will be the amount of intravenous morphine patients self-administer during the 2nd 24 hours post-surgery.

This will be a randomized, double-blinded placebo-controlled study. In this study, women who underwent cesarean section with epidural anesthesia will receive 3 mg of epidural morphine intraoperatively, and have the epidural catheter left in place. Patients will be randomized to receive either epidural saline or epidural morphine 3 mg at 18 - 24 hours after the first dose of epidural morphine, following which the epidural catheter will be removed. It is standard of care at our institution for women undergoing cesarean section with epidural anesthesia to receive epidural morphine 3 mg. What is not typically carried out is to give a second dose of epidural morphine 3mg.

The randomization will be carried out by a computerized block randomization table; the proportion for the 2 groups will be 1:1. The primary outcome will be the amount of intravenous morphine patients self-administer in the second 24 hours after surgery. Secondary outcomes will include pain scores every 6 hours, satisfaction with analgesia, side effects (itching, nausea/vomiting).

Inclusion Criteria:

• Women undergoing cesarean section under epidural anesthesia.

Exclusion Criteria:

• Emergent cesarean section
• Coagulopathy
• Failed epidural anesthesia or patchy block
• General anesthesia
• Use of epidural chloroprocaine
• Allergy or contraindication to Non-steroidal anti-inflammatory drug (NSAIDs)
• Severe opioid side effects
• History of chronic opioid use
• History of chronic pain
• History of obstructive sleep apnea
• Morbid obesity (Body Mass Index (BMI)>45 kg/m2)
• Height under 4' 10" (147 cm)
• Documented dural puncture by the epidural (Tuohy) needle
• Preeclampsia
• Other significant medical disease (American Society of Anesthesiologists (ASA) 3 or more).

Up to 48 hours post-surgery

Women undergoing cesarean section under epidural anesthesia virtually always receive epidural morphine for post-operative analgesia. The 5 women did not experience any unexpected/reportable serious or non-serious adverse effects from the epidural morphine after cesarean section.