Major abdominal surgery is associated with a substantial risk of early postoperative pulmonary complications, including atelectasis, hypoxemia, pneumonia, and increased need for respiratory support. High-flow nasal cannula (HFNC) provides warmed and humidified oxygen at high flow rates and may improve oxygenation, reduce respiratory workload, and support lung volume during the immediate postoperative period. However, whether routine prophylactic HFNC after major abdominal surgery reduces clinically significant postoperative pulmonary complications remains uncertain.
This prospective, single-center, randomized controlled trial will evaluate whether prophylactic HFNC applied for 24 hours immediately after extubation reduces postoperative pulmonary complications compared with standard postoperative respiratory care in adult patients undergoing major abdominal surgery under general anesthesia with an actual anesthetic duration of 3 hours or longer.