Respiratory effects of rectus sheath block in patients undergoing major upper abdominal surgery: a randomized controlled trial

Postoperative pulmonary complications remain a major concern after upper abdominal surgery and are often exacerbated by either inadequate pain control or opioid-based analgesia. We evaluated the analgesic efficacy and respiratory effects of ultrasound-guided RSB in patients undergoing upper abdominal surgery. In this prospective, randomized, controlled trial, 60 patients aged 18–62 years, with ASA I or II status, who underwent upper abdominal surgery under general anesthesia, were enrolled and divided into two groups (30 patients each). RSB Group received ultrasound-guided rectus sheath block after induction of general anesthesia with 40 ml volume of 0.25% bupivacaine and 8 mg dexamethasone (half the volume on each side). The control group received standard anesthesia care without RSB. Pain scores, opioid consumption, diaphragmatic inspiratory amplitude (DIA), and pulmonary function tests were assessed in the immediate postoperative period. Diaphragmatic inspiratory amplitude decreased significantly from baseline at 6, 12, and 24 h postoperatively in both groups (P value < 0.001) with no significant intergroup differences. Forced vital capacity (FVC), forced expiratory volume in first second (FEV1) and Peak expiratory flow rate (PEFR) declined postoperatively in both groups but remained comparable between groups. The RSB group demonstrated significantly lower early postoperative pain scores (P = 0.007), delayed time to first rescue analgesia, reduced total opioid consumption (P < 0.001), and higher patient satisfaction (P = 0.041) with reduced incidence of side effects compared with controls. RSB provided effective opioid-sparing analgesia without impairing pulmonary function. Its simplicity, safety, and compatibility with enhanced recovery after surgery (ERAS) protocols highlight its role as a valuable adjunct to multimodal analgesia in upper abdominal surgery.