Ultrasound-guided four quadrants transversus abdominis plane (TAP) block in emergency laparotomies and the effect of adding magnesium sulfate or dexamethasone as an adjuvant to bupivacaine: a randomized controlled trial

Abstract

Context The lateral transversus abdominus plane (TAP) block can provide sensory blockade of the T10–L1 abdominal dermatomes, which works well for lower abdominal surgery, but it is insufficient in extended upper incisions that may be needed in emergency laparotomies. So, concomitant use of the subcostal TAP block can extend the sensory blockade to the T7 abdominal dermatomes. Aims This clinical trial aimed to evaluate the efficacy and safety of ultrasound-guided four quadrants TAP block in emergency laparotomies and the effect of adding dexamethasone or magnesium sulfate as an adjuvant. Settings Minia University Hospital. Design This is a prospective double-blind, randomized, controlled study. Patients and methods After approval of the Faculty of Medicine Council and Research Ethics Committee − Minia University and clinical trial registration, this study was conducted on 90 adult patients with emergency laparotomies under general anesthesia who equally assigned into three groups that all received preincisional four quadrants TAP block using 38 ml of bupivacaine hydrochloride 0.25%, plus 2 ml of saline in group C, +2 ml of dexamethasone (8 mg) in group D, and +2 ml of magnesium sulfate (200 mg) in group M. Results The four-quadrants TAP block was effective in attenuating the hemodynamic stress response and providing intraoperative and postoperative analgesia [only two (6.7%) patients needed intraoperative fentanyl in the control group and the mean time of the first postoperative analgesia was 6.3±0.9 h] without notable complications. The mean time of the first analgesic request was significantly longer in group M (10.8±3.8 h) and group D (9.6±4.2 h) when compared with group C (6.3±0.9 h); consequently, the postoperative paracetamol doses were significantly lower in group M (1619.5±780.2) and group D (1942.5±969.9) than in group C (3638.8±1251) with no significant difference between D and M groups. Conclusions Four quadrants TAP block was safe and effective in intraoperative and postoperative analgesics in emergency laparotomies. Adding magnesium sulfate or dexamethasone as adjuvants prolonged the duration of analgesia. Magnesium sulfate was superior.