Pneumoperitoneum in peritoneal dialysis patients; one centre’s experience

The pneumoperitoneum (PP) on upright chest X-ray (CXR) usually indicates a perforated viscus. As peritoneal dialysis (PD) catheter provides an additional port of air entry into the peritoneal cavity, the incidence and clinical significance of PP in PD patients has been debated in the literature (a variable incidence from 4 to 34% has been reported in previous studies). With improvement in patient training and connecting devices of PD catheters, technique-related PP is quite rare. Following a recent patient with PP, we reviewed our 3-year data to evaluate the incidence and significance of this radiological sign in PD patients. We reviewed all upright CXRs in our PD patients from 2006 to 2008, using an electronic radiology database. Over 3 years, we had a total of 156 patients on PD. We have reviewed a total 312 upright CXRs (mean 2 X-rays per patient), which were performed for various clinical reasons during this period. Seven PD patients had 11 CXRs showing free air under the diaphragm (total incidence of PP 4% of PD population and 3% of CXR performed in PD patients). One patient had two episodes of PP with a total of four X-rays demonstrating free air. Two patients had surgical complications of PD catheter insertion and PP was diagnosed just after the insertion of PD catheter, both of them needed laparotomy. Five patients had incidental PP, which was possibly technique related. In four of these patients with incidental PP, no definite intervention was needed. However, one of these five patients was symptomatic. We established that the cause of PP was faulty technique. Aspiration of PP with a patient in the Trendelenburg position gave her immediate symptomatic relief. We also retrained her to prevent further episodes of PP. This review demonstrates the quite low and falling incidence of PP (<4% in a prevalent PD population) most likely due to improvement in training and technique. The air should not enter the peritoneal cavity in normal properly performed exchanges. Air under the diaphragm in a PD patient requires appropriate evaluation to exclude visceral perforation. After that, patient technique of PD exchanges should be reviewed. However, if PP persists, aspiration of air can give symptomatic relief.