Pneumoperitoneum and its association with ruptured abdominal viscus

T. G. Winek, H. S. Mosely, G. Grout and D. Luallin
Department of Surgery, Good Samaritan Hospital, Portland, OR.

Pneumoperitoneum is not invariably associated with ruptured or perforated intra-abdominal viscus. To determine the incidence of free air associated with intra-abdominal viscus perforation, the medical records of 77 consecutive patients whose discharge or autopsy diagnosis included pneumoperitoneum or perforated viscus at a community hospital were retrospectively reviewed between June 1980 and October 1985. Abdominal viscus perforation, as determined by contrast studies or at operation, was not invariably associated with free air. Sixty-nine percent (23/33) of gastroduodenal, 30% (3/10) of small-bowel, and 37% (11/30) of large-bowel perforations had free air, as determined by preoperative x-ray film. Four cases with a total of six episodes of pneumoperitoneum were identified where viscus perforation was not documented. Pneumoperitoneum thus remains a reliable sign of viscus perforation; however, lack of this finding does not rule out perforation, and unusual causes must be considered.