Ultrasound guided 0.25% ropivacaine transversus abdominis plane block in addition to intrathecal morphine and multimodal analgesia for the management of postoperative pain among women undergoing cesarean delivery
Abstract Number: 162
Abstract Type: Original Research
INTRODUCTION: Cesarean delivery (CD) is a major surgical procedure after which substantial postoperative pain can be anticipated. Despite neuraxial opioids and multimodal analgesia strategies, severe pain is experienced by 20% of women in the first 24 hours after CD. Severity of postpartum pain is associated with increased chronic pain and postpartum depression. The addition of transversus abdominis plane (TAP) blocks to a multimodal analgesic regimen maybe associated with earlier ambulation and reduced postoperative morbidity and mortality and chronic pain. We hypothesize that an ultrasound guided TAP block as part of a multimodal approach to postoperative analgesia will significantly decrease postoperative pain and potentially reduce the risk of developing persistent pain.
METHODS: This is a randomized double blind placebo controlled clinical trial on women ASA physical status class I & II, age≥18 years, term≥37 weeks gestation, BMI<40, in healthy pregnancies undergoing non-emergent CD with planned spinal anesthesia. Spinal anesthesia was standardized (hyperbaric 0.75% bupivacaine - 12mg, fentanyl - 15mcg, morphine - 100mcg). Bilateral TAP blocks were inserted with ultrasound guidance with injection of 20mls of study solution per side (ropivacaine 0.25% or saline). Three primary outcome measures: the Numeric Rating Scale (NRS), Quality of Recovery 40 (QoR), and opioid consumption at 24 hours were used for a priori sample size calculation with α=0.05 and β=0.20 to detect a 30% reduction in the NRS, a 10% improvement in QoR score and a 50% reduction in opioid consumption (10% drop out rate) yielded 34 subjects per group. Multiple secondary outcomes included pain at rest/movement, nausea and vomiting, pruritis, urinary retention, etc at 2-hour and 48-hour, and the SF36 questionnaire at 30 days and 6 months.
RESULTS: With REB approval and informed consent 83 subjects were enrolled with 75 completing the trial. Table 1 contains the blinded population demographics and 24-hour pain measures.
DISCUSSION: Two hour pain scores (NRS-rest) and oxycodone use appear to be statistically significant. Data analysis will be complete with final results presented at SOAP in Lake Las Vegas.