Complex Obstetric SurgeryPhase 4COMFORTNCT06925152
COMFORT Trial: Complex Obstetric Management With Focused Regional Transversus Abdominis Plane Block
A Phase 4 study testing Bupivicaine intervention arm in people with Complex Obstetric Surgery and Perioperative Pain Management, run by University of Tennessee at 1 site in United States.
Trial summary
To assess the effect of intraoperative transversus abdominis plane (TAP) blocks on the amount of opioid pain medications expressed as morphine milliequivalents (MME) used postoperatively in patients who have undergone cesarean delivery (CD) in the setting of complex obstetric surgery (COS). Read more about this study
- Who is it for?
- Ages 18 to 50 years, women only
- Conditions the study is for
- Complex Obstetric Surgery, Perioperative Pain Management, Cesarean Delivery
- What is being tested?
- Bupivicaine intervention arm
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 120 participants
- Where
- 1 siteUnited States
- Study dates
- 15 Jul 2025to May 2028
- Phase
- Phase 4
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 50 years
- Women only
- No healthy volunteers
- Adult
Who may be able to join
- Patient has a history of a least one of the following:
- Prior exploratory laparotomy
- History of non-obstetric open intra-abdominal surgery
- History of three or more prior cesarean deliveries
- History of intra-abdominal or pelvic adhesive disease
- History of abdominal re-exploration surgery
Who cannot join
- Planned general anesthesia
- Supraumbilical skin incision
- History of less than 3 cesarean deliveries if do not meet other inclusion criteria
- History of chronic opioid use
- History of substance abuse (i.e. alcohol, methamphetamine/amphetamine, abuse of prescription opioid medication, or heroin use)
- History of chronic kidney disease
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- Allergies to bupivacaine or oral analgesics
- Patient preference
- Planned cesarean hysterectomy
- Administration of >4mg morphine to epidural
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Regional One Health
Memphis, Tennessee, 38103
Michael Vandillen, MD, 314-619-1046, mvandill@uthsc.edu
About this study
To assess the effect of intraoperative transversus abdominis plane (TAP) blocks on the amount of opioid pain medications expressed as morphine milliequivalents (MME) used postoperatively in patients who have undergone cesarean delivery (CD) in the setting of complex obstetric surgery (COS).
Read the detailed description
The Transversus Abdominis Plane (TAP) block is a regional anesthesia technique that targets the nerves innervating the abdominal wall, providing effective postoperative analgesia for patients undergoing various abdominal surgeries, including cesarean deliveries. The standard clinical practice for TAP blocks typically involves local anesthetics like bupivacaine, which, when administered in the appropriate plane, has been shown to reduce opioid consumption and improve pain management in the postoperative period.
Transversus abdominal plane (TAP) blocks, when administered intraoperatively, have demonstrated significant benefits in managing postoperative pain, especially in abdominal surgeries. Placing the TAP block during surgery provides early and prolonged analgesia, potentially reducing the need for postoperative opioids and improving recovery outcomes. A study completed in 2007 was one of the first to highlight the effectiveness of intraoperative TAP block placement in patients undergoing lower abdominal surgeries, showing a significant reduction in opioid consumption and better pain control. In the context of cesarean section, an intraoperative TAP block was shown to provide effective analgesia with a reduction in postoperative narcotic use. Similarly, a randomized trial in 2017 demonstrated that intraoperative TAP blocks significantly improved pain scores and reduced opioid consumption in patients undergoing colorectal surgeries. Furthermore, a study completed in 2014 found that performing TAP blocks intraoperatively for laparoscopic cholecystectomy patients resulted in lower visual analog scale (VAS) pain scores in the recovery room and reduced the incidence of postoperative nausea and vomiting. These findings underscore the advantages of intraoperative TAP block placement in enhancing postoperative analgesia across a variety of abdominal procedures.
Despite the widespread use of TAP blocks, there remains a gap in the literature regarding the effectiveness of bupivacaine TAP block use placed intraoperatively during more complex obstetric surgeries. Most existing studies focus on the use of TAP blocks for pain management after routine Pfannenstiel cesarean deliveries, with limited attention given to their role in cases involving higher-risk or more complicated obstetric situations, such as cesareans with significant intra-abdominal adhesions or other complications.
Although bupivacaine is commonly used in TAP blocks, its specific efficacy, optimal dosing, and potential benefits when placed intraoperatively in complex obstetric cases remain underexplored. The limited data in this area presents a critical gap in our understanding of how best to optimize pain management and improve surgical outcomes for women undergoing cesarean delivery, particularly in high-risk obstetric cases.
This blinded randomized controlled trial (RCT) seeks to address this gap by evaluating the effectiveness of intraoperative TAP blocks with bupivacaine during complex cesarean sections, focusing on the impact on postoperative analgesia and pain scores. By clarifying the role of bupivacaine in TAP blocks during complex obstetric surgery, this study aims to contribute valuable insights to the field of obstetric anesthesia and improve the perioperative experience for patients undergoing cesarean delivery.
Primary Objective: To assess the effect of intraoperative transversus abdominis plane (TAP) blocks on the amount of opioid pain medications expressed as morphine milliequivalents (MME) used postoperatively in patients who have undergone cesarean delivery (CD) in the setting of complex obstetric surgery (COS).
Primary Endpoint/Outcome: Pain medication requested, expressed as MMEs, from 0-24 and 0-48 hours after surgery.
Secondary Endpoint(s)/Outcome(s):
Total MME at 1-week after surgery Functional assessment of activities of daily life (ADL) at 1-week post operatively Number of unplanned postoperative visits within 6-months of surgery Geographic region of patients needing complex obstetric surgery.
Hypothesis: The investigators hypothesize that utilization of the TAP block will reduce MME requirements by 20% for patients who have undergone CD in the setting of COS.
- Conditions
- Complex Obstetric Surgery, Perioperative Pain Management, Cesarean Delivery, Postoperative Pain Control
- Being tested
- Bupivicaine intervention arm, Placebo arm
- Keywords
- Complex obstetric surgery, Perioperative pain management, cesarean delivery, postoperative pain control
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Bupivicaine intervention armDrug
TAP blocks in intervention group will include 0.5% bupivacaine in 30mL solution of 15mL normal saline and 15mL bupivacaine
Placebo armDrug
Placebo group TAP block syringe will include 30mL normal saline
| Study group | Role | What they receive |
|---|---|---|
| Placebo group | Placebo comparator | Placebo group TAP (Transversus Abdominis Plane) block syringe will include 30mL normal saline. Receives: Drug: Placebo arm |
| Intervention group | Active comparator | TAP (Transversus Abdominis Plane) blocks will include 0.5% bupivacaine in 30mL solution of 15mL normal saline and 15mL bupivacaine. Receives: Drug: Bupivicaine intervention arm |
What is being measured
The primary outcome is the main question the study is designed to answer.
Pain medication requested
Total pain medication requested expressed in morphine milligram equivalents.
Measured: Between 0-24 and 0-48 hours after surgery
Secondary outcomes (4)
Total MME at one week after surgery
Measured: One week postoperatively
Functional assessment of activities of daily life (ADL) at one week postoperatively
Measured: One week postoperatively
Number of unplanned postoperative visits within six months of surgery
Measured: Six months postoperatively
Geographic region of patients needing complex obstetric surgery
Heat maps to evaluate the distribution of patients across different demographic categories based on race and age within certain zip codes
Measured: 24 months - through the duration of the study
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Apr 2025
- Study start15 Jul 2025
- Primary completionMay 2028 (estimated)
- Study completionMay 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (7)Papers the sponsor has linked to this study.
- Other trials for Complex Obstetric SurgeryStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Multi-year (February 2025- February 2028) prospective double blinded randomized-control trial
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 120 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Tennessee
- Sponsor type
- University, hospital or other
- Collaborators
- Regional One Health
- Responsible party
- Principal investigator, Michael B VanDillen MD, University of Tennessee
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06925152
- Sponsor's protocol ID
- COMFORT2025
- Acronym
- COMFORT
- Status last verified
- Oct 2026
- First submitted
- 19 Mar 2025
- Last updated
- 21 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
McDonnell JG, O'Donnell B, Curley G, Heffernan A, Power C, Laffey JG. The analgesic efficacy of transversus abdominis plane block after abdominal surgery: a prospective randomized controlled trial. Anesth Analg. 2007 Jan;104(1):193-7. doi: 10.1213/01.ane.0000250223.49963.0f.
PubMed 17179269Johns N, O'Neill S, Ventham NT, Barron F, Brady RR, Daniel T. Clinical effectiveness of transversus abdominis plane (TAP) block in abdominal surgery: a systematic review and meta-analysis. Colorectal Dis. 2012 Oct;14(10):e635-42. doi: 10.1111/j.1463-1318.2012.03104.x.
PubMed 22632762Zhang, X., et al. (2017).
Kehlet, H., et al. (2014).
Garmi G, Parasol M, Zafran N, Rudin M, Romano S, Salim R. Efficacy of Single Wound Infiltration With Bupivacaine and Adrenaline During Cesarean Delivery for Reduction of Postoperative Pain: A Randomized Clinical Trial. JAMA Netw Open. 2022 Nov 1;5(11):e2242203. doi: 10.1001/jamanetworkopen.2022.42203.
PubMed 36378307Abdallah FW, Halpern SH, Margarido CB. Transversus abdominis plane block for postoperative analgesia after Caesarean delivery performed under spinal anaesthesia? A systematic review and meta-analysis. Br J Anaesth. 2012 Nov;109(5):679-87. doi: 10.1093/bja/aes279. Epub 2012 Aug 19.
PubMed 22907337Ueshima, H., Higashijima, U., Matsumoto, M., & Imai, S. (2013). The effect of the volume of local anesthetic on the analgesic effect of transversus abdominis plane block in abdominal surgery. Journal of Anesthesia, 27(6), 650-655.