Ultrasound-guided single injection transversus abdominis plane block of isobaric bupivacaine with or without dexamethasone for bariatric patients undergoing laparoscopic vertical banded gastroplasty: a comparative study of different doses

Background Dexamethasone has anti-inflammatory properties that can prolong postoperative analgesia when added to isobaric bupivacaine transversus abdominis plane ( TAP) block for bariatric patients undergoing laparoscopic vertical banded gastroplasty. Patients and methods A total of 111 bariatric patients, scheduled for laparoscopic vertical banded gastroplasty under ultrasound-guided TAP block, were randomized blindly into three parallel groups: Group BC that received TAP block using 20 ml of isobaric bupivacaine hydrochloride 0.25%+2 ml saline 0.9%; low-dose dexamethasone group (Group DB4) that received TAP block using 20 ml of isobaric bupivacaine hydrochloride 0.25%+4 mg dexamethasone; and high-dose dexamethasone group (Group DB8) that received TAP block using 20 ml of isobaric bupivacaine hydrochloride 0.25%+8 mg dexamethasone. Results Postoperatively, pain scores were significantly lower in Group BD4 and Group BD8 compared with Group BC at rest and on movement at 6, 8, 12, and 24 h. There was a significant difference with respect to the duration of analgesia (P = 0.0001), 24 h consumption of paracetamol (P = 0.0001), 24 h consumption of meperidine hydrochloride (P = 0.001), the number of patients who needed meperidine hydrochloride rescue analgesic (P = 0.008), time to ambulation (P = 0.0001), and incidence of postoperative nausea and/or vomiting (P = 0.03) among groups. Conclusion Adding dexamethasone (4 or 8 mg) to isobaric bupivacaine TAP block reduces postoperative pain, reduces analgesic requirement, and promotes early ambulation in bariatric patients undergoing laparoscopic vertical banded gastroplasty in comparison with isobaric bupivacaine TAP block alone.