Pneumoperitoneum in perforated peptic ulcer; factors in roentgenographic demonstration.

Evidence compiled in review of data on 324 cases of perforated gastric or duodenal ulcer indicated that pneumoperitoneum is more likely to be demonstrated in roentgen films made within six hours after perforation than in films made after a longer interval. In several cases films made early did not show intraperitoneal gas and later films did. There appeared to be no constant relationship between the size of the perforation and the incidence of demonstrable pneumoperitoneum. Pneumoperitoneum was less often demonstrated in cases of posterior perforation than it was when the lesion was at an anterior site. In many cases roentgen examination was performed with the patient in both the erect and the left lateral decubitus positions. These two roentgenographic views were equally reliable and there was agreement between them in 94 per cent of the cases. Clinical factors, however, may influence decision as to which position should be used in each case. Occasionally when intraperitoneal gas is not demonstrated in one view, it may be observed in films made with the patient in the other position.