COMFORT Trial: Complex Obstetric Management With Focused Regional Transversus Abdominis Plane Block (COMFORT)

March 8, 2026 updated by: Michael B VanDillen MD, University of Tennessee
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).

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

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, between 24 and 48 hours after surgery.

Secondary Endpoint(s)/Outcome(s):

Total MME requested within first 24-hours post operatively Total MME requested within 48-hours post operatively 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. Heat maps: diversity equity and inclusion (DEI) zip codes

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.

Study Type

Interventional

Enrollment (Estimated)

120

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: Michael VanDillen Fellow physician, PI of study, MD
  • Phone Number: 314-619-1046
  • Email: mvandill@uthsc.edu

Study Locations

  • United States
    • Tennessee
      • Memphis, Tennessee, United States, 38103
        • Recruiting
        • Regional One Health
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion criteria:

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 abdominoplasty
  • History of abdominal re-exploration surgery

Exclusion Criteria:

  • Received general anesthesia
  • 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
  • Allergies to bupivacaine or oral analgesics
  • Patient preference
  • Cesarean hysterectomy
  • Administration of ≥4mg morphine to epidural
  • Loss to follow-up

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Placebo group
Placebo group TAP (Transversus Abdominis Plane) block syringe will include 30mL normal saline.
Drug: Placebo arm
Placebo group TAP block syringe will include 30mL normal saline
Active Comparator: Intervention group
TAP (Transversus Abdominis Plane) blocks will include 0.5% bupivacaine in 30mL solution of 15mL normal saline and 15mL bupivacaine.
Drug: Bupivicaine intervention arm
TAP blocks in intervention group will include 0.5% bupivacaine in 30mL solution of 15mL normal saline and 15mL bupivacaine

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pain medication requested
Time Frame: Between 24 and 48 hours after surgery
Total pain medication requested expressed in morphine milligram equivalents.
Between 24 and 48 hours after surgery

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Total MME requested within first 24 hours postoperatively
Time Frame: 24 hours postoperatively
24 hours postoperatively
Total MME requested within 48 hours postoperatively
Time Frame: 48 hours postoperatively
48 hours postoperatively
Total MME at one week after surgery
Time Frame: One week postoperatively
One week postoperatively
Functional assessment of activities of daily life (ADL) at one week postoperatively
Time Frame: One week postoperatively
One week postoperatively
Number of unplanned postoperative visits within six months of surgery
Time Frame: Six months postoperatively
Six months postoperatively
Geographic region of patients needing complex obstetric surgery
Time Frame: 24 months - through the duration of the study
Heat maps to evaluate the distribution of patients across different demographic categories based on race and age within certain zip codes
24 months - through the duration of the study

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Tennessee

Collaborators

Regional One Health

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

July 15, 2025

Primary Completion (Estimated)

May 1, 2028

Study Completion (Estimated)

May 1, 2028

Study Registration Dates

First Submitted

March 19, 2025

First Submitted That Met QC Criteria

April 5, 2025

First Posted (Actual)

April 13, 2025

Study Record Updates

Last Update Posted (Actual)

March 11, 2026

Last Update Submitted That Met QC Criteria

March 8, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • COMFORT2025

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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