Transverse Abdominis Plane (TAP) Block After Cesarean Delivery

This study is currently recruiting participants. (see Contacts and Locations)
Verified August 2015 by Northwestern University
Information provided by (Responsible Party):
Christopher Cambic, Northwestern University Identifier:
First received: July 23, 2010
Last updated: August 3, 2015
Last verified: August 2015

Cesarean delivery is the most commonly performed surgical procedures in the United States today, with over 1.2 million cases performed in 2005.1 One of the most important aspects of cesarean delivery is the provision of safe, effective postoperative analgesia for the mother, while simultaneously ensuring minimal side effects for both the mother and neonate. Studies have suggested that a multimodal approach to post-cesarean pain utilizing both intravenous, oral, and neuraxial opioids and non-steroidal anti-inflammatory drugs is highly effective in providing effective analgesia.2-4 A significant component of post-cesarean pain is incisional pain from the Pfannenstiel incision on the anterior abdominal wall. The sensory supply to the skin, muscles, and parietal peritoneum of the anterior abdominal wall is derived from the anterior rami of T7-L1. After exiting the spinal column, these nerves proceed through the lateral abdominal wall within the transversus abdominal fascial plane, terminating in the anterior abdominal wall.6,7 Recent studies have suggested that blocking these afferent sensory nerves with local anesthetics, as part of a multimodal postoperative pain regimen, provides superior pain relief in terms of decreased pain scores and morphine consumption for up to 48 hours postoperatively.8-10 The technique utilized for these studies employed a surface anatomical approach to the transversus abdominal fascial plane via the lumbar triangle of Petit, a technique validated in both cadaveric and radiologic studies.11 However, as ultrasonography has emerged as the "gold standard" for initiating many nerve blocks, reports have described the successful use of ultrasound imaging for initiation of transversus abdominis plane (TAP) blocks for both abdominal surgeries and cesarean deliveries.

In the published studies investigating the use of the TAP block for post-operative analgesia, either ropivacaine or bupivacaine was utilized in concentrations of 0.75% and 0.375%, respectively. Studies comparing ropivacaine with bupivacaine for use in interscalene, femoral, or sciatic nerve blocks have found no difference in terms of potency, time to onset or duration of postoperative analgesia between the two local anesthetics. Although no similar studies have been done with TAP blocks, one can assume that utilization of ropivacaine for this nerve block would yield similar results in terms postoperative analgesia. Moreover, the cardiotoxicity of ropivacaine has been shown to be significantly less than bupivacaine, making it a safer alternative for use in nerve blocks when used in high doses.Risk factors for respiratory depression after the administration of neuraxial opioids in the non-obstetric population include morbid obesity and obstructive sleep apnea. For the obstetric population, a study of 856 patients revealed that all 8 patients who experienced respiratory depression after intrathecal morphine for cesarean delivery were markedly obese. Furthermore, the onset of respiratory depression after intrathecal morphine can occur up to 12 hours after administration, a time period when the patient is not being as closely monitored as she is during the 1:1 nursing care in the recovery room. Therefore, it is the investigators policy on the Labor and Delivery unit to not administer intrathecal morphine to any parturient with a history of obstructive sleep apnea or a BMI > 40 kg/m2. As such, these patients often require intravenous opioid patient-controlled analgesia postoperatively, which has been shown to provide inferior pain relief and greater opioid consumption than neuraxial opioids. Moreover, the current clinical standard is to administer the TAP block to those patients who have not received morphine in their neuraxial anesthetic. Hence, the TAP block offers a novel addition to the management of post-cesarean pain for this patient population.

Since there have been no published dose-response studies investigating the effective analgesic dose of ropivacaine for use in a TAP block for post-Cesarean delivery analgesia, the investigators propose a study primarily examining the effect on 24 hour post-Cesarean delivery opioid consumption of using either a placebo, 0.25% ropivacaine, 0.5% ropivacaine, or 0.75% ropivacaine for TAP blocks.

Condition Intervention Phase
Cesarean Delivery
Pain Relief
TAP Block
Drug: Placebo
Drug: Group 2 - 15mL 0.25% ropivacaine per side
Drug: . Group 3
Drug: 15mL 0.75% ropivacaine per side
Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Investigator)
Primary Purpose: Prevention
Official Title: The Postoperative Analgesic Efficacy of Varied Concentrations of Ropivacaine Used for the Transverse Abdominis Plane (TAP) Block After Cesarean Delivery

Resource links provided by NLM:

Further study details as provided by Northwestern University:

Primary Outcome Measures:
  • hydromorphone consumption [ Time Frame: 24 hours ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • opioid consumption (morphine equivalents) [ Time Frame: 48 hours ] [ Designated as safety issue: No ]
  • opioid consumption (morphine equivalents) [ Time Frame: 72 hours ] [ Designated as safety issue: No ]

Estimated Enrollment: 200
Study Start Date: January 2010
Estimated Study Completion Date: December 2016
Estimated Primary Completion Date: December 2016 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Placebo Comparator: Placebo
a. Group 1 (Placebo Group) - 15mL 0.9% normal saline per side
Drug: Placebo
Active Comparator: Group 2
Group 2 - 15mL 0.2% ropivacaine per side
Drug: Group 2 - 15mL 0.25% ropivacaine per side
15mL 0.2% ropivacaine per side
Active Comparator: Group 3
15mL 0.5% ropivacaine per side
Drug: . Group 3
15mL 0.5% ropivacaine per side
Active Comparator: . Group 4
15mL 0.75% ropivacaine per side
Drug: 15mL 0.75% ropivacaine per side
15mL 0.75% ropivacaine per side


Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Female
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • ASA II-III patient
  • > 18 years of age who is pregnant
  • presenting for a cesarean delivery via Pfannenstiel incision who is eligible to receive a spinal anesthetic with 0.75% bupivacaine and fentanyl and whose is not eligible to receive intrathecal morphine due to a BMI >40 kg/m2.

Exclusion Criteria:

  • < 18 years of age
  • contraindication to placement of a spinal anesthetic
  • contraindication to use of non-steroidal anti-inflammatory drugs (NSAIDs)
  • patients receiving medical therapies considered to result in tolerance to opioids
  • patients with a history of established chronic pain, (e.g. chronic low back pain, fibromyalgia or headaches), defined as requiring regular medical follow-up with pain specialists, as well as recent use (within the year preceding pregnancy) of opioid analgesics as an outpatient
  • patients with a history of diabetes mellitus
  • patients undergoing a vertical midline skin incision
  • patients who are undergoing a cesarean delivery after a failed vaginal trial of labor
  • patients who had a prior epidural placed for labor analgesia during the same hospital encounter.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01170702

Contact: Christopher Cambic, M.D. 312-926-8373

United States, Illinois
Northwestern University Recruiting
Chicago, Illinois, United States, 60611
Contact: Christopher Cambic, M.D.    312-926-8373   
Principal Investigator: Christopher Cambic, M.D         
Sponsors and Collaborators
Northwestern University
Principal Investigator: Christopher Cambic, M.D. Northwestern University
  More Information


Responsible Party: Christopher Cambic, Assistant Professor, Northwestern University Identifier: NCT01170702     History of Changes
Other Study ID Numbers: STU00008429 
Study First Received: July 23, 2010
Last Updated: August 3, 2015
Health Authority: United States: Institutional Review Board

Keywords provided by Northwestern University:
Cesarean Delivery
TAP block

Additional relevant MeSH terms:
Anesthetics, Local
Central Nervous System Agents
Central Nervous System Depressants
Peripheral Nervous System Agents
Pharmacologic Actions
Physiological Effects of Drugs
Sensory System Agents
Therapeutic Uses processed this record on May 04, 2016