Postoperative pneumoperitoneum: is it normal or pathologic?

Background: Pneumoperitoneum on computed tomography (CT) after abdominal surgery is common, but its incidence, duration, and clinical significance is widely debated.

Materials And Methods: A retrospective, cohort study of patients who underwent abdominal CT within 30 days of abdominal surgery.

Results: Among 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%).

Conclusions: Postoperative 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.