Effect of Two Doses of Hyaluronidase with Bupivacaine in Ultrasound-Guided Transversus Abdominis Plane Block for Post Cesarean Delivery Pain: A Randomized Trial.

BACKGROUND

A transversus abdominis plane block provides reliable abdominal wall analgesia, but which adjuvants best sustain its effect remains debated. By facilitating diffusion of local anesthetics, hyaluronidase may improve block quality.

OBJECTIVES

This study evaluated the safety and efficacy of 2 hyaluronidase doses added to bupivacaine for bilateral transversus abdominis plane blocks in patients having a cesarean delivery.

STUDY

DESIGN

A prospective, randomized, double-blind, controlled clinical trial.

SETTING

Benha University Hospital, Arab Republic of Egypt, from May 2023 through February 2024.

METHODS

A double-blind, controlled randomized trial was performed with 114 patients having elective cesarean delivery. The patients were allocated equally into 3 arms: Group I (bupivacaine alone), Group II (bupivacaine plus 750 IU hyaluronidase), and Group III (bupivacaine plus 1500 IU hyaluronidase). The time to first rescue analgesia served as the primary outcome. Secondary outcomes encompassed 24-hour morphine requirements, Visual Analog Scale pain score at rest and on coughing, patient satisfaction, hemodynamics, and adverse events. Analyses employed the appropriate statistical tests (parametric or nonparametric), with subsequent post hoc comparisons for significant findings.

RESULTS

Both hyaluronidase groups had significant prolonged analgesia (median 8.1 hours and 9.6 hours) compared to the control group (5.8 hours) (P < 0.001). Morphine requirements over the first postprocedure 24 hours diminished significantly (P < 0.001); Groups II and III had lower pain scores at rest and on coughing between postprocedure hours 2 and 12 (all P < 0.05). Patient satisfaction increased with hyaluronidase (P = 0.0039). No group differences were observed for adverse events, including postoperative nausea and vomiting or local anesthetic toxicity.

LIMITATIONS: This single-center trial with 24-hour follow-up may restrict generalizability and long-term safety assessment; also only 2 hyaluronidase doses were examined.

CONCLUSIONS

Adding hyaluronidase to bupivacaine for transversus abdominis plane block enhances analgesic duration and quality without compromising safety in patients having cesarean delivery. Both high and low doses appear equally effective, suggesting that even lower doses are sufficient for optimal effect.