Increased use of Hypertonic Dialysate by CAPD Patients following Repeated Episodes of Peritonitis

Many investigators are concerned that in patients receiving long-term CAPD, repeated episodes of peritonitis may reduce the ultrafiltration capacity of the peritoneum. In our CAPD program, patients who had had no previous episodes of peritonitis used an average of 0.68 hypertonic exchanges per day, compared to 2.13 hypertonic exchanges required by patients who had had two or more episodes of peritonitis. When this phenomenon was examined in more detail, we found that the increase in the number of hypertonic exchanges could be explained by two factors. Daily urine output fell from an average of 585 ml in the peritonitis-free group to 284 ml in the group with recurrent peritonitis. The latter group needed more hypertonic exchanges to stay in fluid balance. Apparent fluid intake during a 64hour period was calculated in 13 CAPD patients. This increased from 3909 ml in those with no peritonitis to 6267 ml in those with two or more episodes of peritonitis. In a separate study, we measured drainage volume with a hypertonic exchange in 19 CAPD patients. There was no apparent relationship between drainage volume and the number of previous episodes of peritonitis or between drainage volume and the length of time on CAPD.

We conclude that there is increased use of hypertonic exchanges in CAPD patients with a history of frequent peritonitis but this can be explained by factors other than a decrease in the ultrafiltration capacity of the peritoneum.