Effects of Anesthesia Techniques on Tissue Oxygenation and Recovery in Lower Abdominal Surgery

This is a prospective observational study designed to evaluate the effects of different anesthesia techniques on tissue oxygenation and postoperative recovery in patients undergoing lower abdominal surgery. A total of 180 patients will be enrolled and evenly allocated into four groups based on the anesthesia method used: general anesthesia, spinal anesthesia, epidural anesthesia, and combined general plus epidural anesthesia. Near-infrared spectroscopy (NIRS) will be utilised to monitor tissue oxygenation at the thenar and plantar regions during the perioperative period. Vital signs, VAS scores(min 0-max 10 points), Quality of Recovery-40 (QoR-40) scores(min 40-max 200 points), and additional postoperative recovery parameters- including length of stay in the post-anesthesia care unit and hospital, surgical site infection, wound revision, and mortality- will be recorded and compared across the groups. The primary hypothesis is that regional anesthesia techniques enchance tissue oxygenation and are associated with improved postoperative recovery outcomes compared to general anesthesia alone. The study was approved by the local ethics committee and will be conducted at a single tertiary-care center.