Postoperative pneumoperitoneum: is it normal or pathologic?

BackgroundPneumoperitoneum on computed tomography (CT) after abdominal surgery is common, but its incidence, duration, and clinical significance is widely debated.Materials and methodsA retrospective, cohort study of patients who underwent abdominal CT within 30 days of abdominal surgery.ResultsAmong 344 patients, pneumoperitoneum was found in 39% (135/344) of patients on postoperative days 0–6 in 53%, 7–13 in 41%, 14–20 in 23%, 21–27 in 13%, and 28–30 in 0%. Pneumoperitoneum was associated with the presence of a drain (P = 0.014) but not with age, gender, body mass index, smoking history, lung disease, or open versus laparoscopic surgery (P > 0.05 for all variables). Eight patients required intervention (6%), most commonly for anastomotic leak (4 patients, 50%).ConclusionsPostoperative pneumoperitoneum on abdominal CT can be seen in up to 23% of patients 3-weeks postoperatively; however, only 6% of the patients required intervention emphasizing the typically benign consequences of postoperative free air.