The Efficacy of Ultrasound-guided Transversus Abdominis Plane Block Versus Quadratus Lumborum Block for Postoperative Analgesia in Lower-Segment Cesarean Section with Low-Dose Bupivacaine: A Randomized Controlled Trial.

Background and objectives: The study sought to compare the postoperative analgesia after ultrasonography (USG)-guided bilateral transversus abdominis plane (TAP) block versus quadratus lumborum (QL) 1 block with lower concentration of bupivacaine in patients undergoing lower-segment cesarean section (LSCS).

Materials and methods: A randomized controlled trial was conducted at a tertiary hospital, Bengaluru, from 2019 to 2021. Fifty-six patients belonging to the American Society of Anesthesiologists physical status Class I and II aged 20-40 years posted for LSCS under subarachnoid block were divided into two groups. Patients in Group I were given bilateral TAP block and patients in Group II were given bilateral QL1 block under USG guidance at the end of surgery using 0.125% bupivacaine (20 ml) and 4 mg dexamethasone. Patients were monitored for postoperative pain with Numerical Pain Intensity Scale (NPIS) at 0, 1, 4, 8, 12, and 24 h. Rescue analgesic was given if NPIS score was 6 or more. Time to first dose of rescue analgesic was noted. NPIS scores and time to rescue analgesic were compared using independent t test. P < 5% was considered statistically significant.

Results: Average NPIS scores were less at 0, 1, and 4 h (<6) and higher at 8, 12, and 24 h in both the groups postoperatively. NPIS scores at 8 h were significantly higher in Group I compared to Group II (P = 0.02). Time to first dose of rescue analgesic was 7.32 h in Group I and 9.07 h in Group II (P < 0.001).

Conclusions: Postoperative analgesia was better with USG-guided QL1 block versus USG-guided TAP block with 0.125% bupivacaine and 4 mg dexamethasone in patients undergoing LSCS.