Air floating loose inside the abdomen is one of the most alarming findings on a scan, because it often means the bowel has broken open. Yet after an abdominal operation, studies have found leftover air on many CT scans in the first few days, sometimes on most of them.
That overlap leaves surgeons with a hard call, and a March 2026 report in the Journal of Surgical Case Reports shows how it plays out. Ten days after part of his colon was removed, a 90-year-old man at Nelson Hospital in New Zealand developed a fever. A chest X-ray ordered for suspected pneumonia confirmed the pneumonia but also showed a massive amount of free air in his abdomen. New or growing air after bowel surgery, the authors wrote, is almost always a sign of catastrophe.
