Fixed-Mass Different Volumes Bupivacaine TAP Block After Cesarean

Ultrasound-guided Transversus Abdominis Plane Block After Cesarean Section Using Two Different Bupivacaine Volumes With a Fixed Drug Mass. A Randomized Comparative Trial.

Cesarean section is commonly associated with moderate to severe postoperative pain, which may delay mobilisation, impair breastfeeding, and affect mother-infant bonding. Although opioids, NSAIDs, and neuraxial techniques are commonly used for post-cesarean analgesia, their side effects have encouraged the use of peripheral nerve blocks such as the transversus abdominis plane block.

The TAP block is a fascial plane block that provides analgesia by depositing local anaesthetic between the internal oblique and transversus abdominis muscles. Its efficacy after cesarean section has been demonstrated, particularly when long-acting intrathecal opioids are not used. However, the optimal local anaesthetic volume and dose remain unclear. Since the TAP block depends on adequate spread of local anaesthetic, larger volumes may improve analgesic coverage, but increasing the dose may raise the risk of systemic toxicity.

Therefore, this study investigates whether using the same fixed mass of bupivacaine in two different volumes affects the analgesic efficacy of TAP block after cesarean section, hypothesising that the larger volume may provide better postoperative analgesia.

Study Overview

• Status: Not yet recruiting
• Conditions: Postoperative Pain; Caesarean Section; TAP Block
• Intervention / Treatment: Drug: Bupivacaine; Drug: Bupivacaine

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Phase 4

Contacts and Locations

• Study Contact: Name: Abeer Ahmed, MD; Phone Number: +201005244590; Email: abeer_ahmed@kasralainy.edu.eg

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• full-term parturients,
• aged > 18 years
• ASA physical status II
• patients who are scheduled for elective CS with Pfannenstiel incisions under spinal anaesthesia.

Exclusion Criteria:

• Parturients with contraindications to spinal anaesthesia,
• Having a scar or infection at the site of the block
• BMI > 35 Kg/m2,
• on chronic use of pain medications,
• Refusing to participate.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Fixed-mass, high-volume bupivacaine TAP block; Participants will receive a bilateral ultrasound-guided TAP block using 150 mg of plain bupivacaine, diluted to a total volume of 60 mL, injected as 30 mL per side.	Drug: Bupivacaine; Ultrasound-guided bilateral transversus abdominis plane block using 150 mg plain bupivacaine after cesarean section. The same total bupivacaine dose will be administered in two different volumes: 60 mL total volume, 30 mL per side; Drug: Bupivacaine; Ultrasound-guided bilateral transversus abdominis plane block using 150 mg plain bupivacaine after cesarean section. The same total bupivacaine dose will be administered in two different volumes: 120 mL total volume, 60 mL per side.
Experimental: Fixed-mass, low-volume bupivacaine TAP block; Participants will receive a bilateral ultrasound-guided TAP block using 150 mg of plain bupivacaine, diluted to a total volume of 120 mL, injected as 60 mL per side.	Drug: Bupivacaine; Ultrasound-guided bilateral transversus abdominis plane block using 150 mg plain bupivacaine after cesarean section. The same total bupivacaine dose will be administered in two different volumes: 60 mL total volume, 30 mL per side; Drug: Bupivacaine; Ultrasound-guided bilateral transversus abdominis plane block using 150 mg plain bupivacaine after cesarean section. The same total bupivacaine dose will be administered in two different volumes: 120 mL total volume, 60 mL per side.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
total postoperative morphine consumption	first 24 hours postoperatively

Collaborators and Investigators

• Sponsor: Cairo University

Study record dates

Study Major Dates

• Study Start (Estimated): June 6, 2026
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): October 1, 2026

Study Registration Dates

• First Submitted: May 16, 2026
• First Submitted That Met QC Criteria: May 29, 2026
• First Posted (Actual): June 1, 2026

Study Record Updates

• Last Update Posted (Actual): June 1, 2026
• Last Update Submitted That Met QC Criteria: May 29, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Postoperative Complications; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain, Postoperative; Organic Chemicals; Anilides; Amides; Aniline Compounds; Amines; Bupivacaine
• Other Study ID Numbers: MD-185-2023

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: No
• Studies a U.S. FDA-regulated device product: No