A comparison of clearances on tidal peritoneal dialysis and intermittent peritoneal dialysis.
OBJECTIVE
To compare the small molecule clearances on tidal peritoneal dialysis (TPD) and intermittent peritoneal dialysis (IPD), controlling for dialysate flow rate.


METHODS
Alternating 8-hour treatments on IPD and TPD (2 of each in 6 patients), each treatment separated by 3 or more days [patients returning to continuous ambulatory peritoneal dialysis (CAPD) in the interim] were performed. IPD treatments consisted of 15 exchanges with 2 L/exchange for a total of 30 L/treatment. TPD treatments consisted of 29 exchanges, with an initial fill volume of 2 L, followed by 1 L tidal volume for the subsequent exchanges (reserve volume of 1 L) for a total of 30 L/treatment.


METHODS
Six patients, with a mean dialysate/plasma (D/P) creatinine as determined by the peritoneal equilibration test (PET) of 0.64 +/- 0.10, were studied. Four had a low-average D/P creatinine, while 2 had a high-average D/P creatinine.


METHODS
Urea nitrogen, creatinine, phosphate, and potassium clearances on TPD and IPD were compared using the paired t-test.


RESULTS
The dialysate flow rates were 3.7 +/- 0.1 L/hour for IPD and 3.8 +/- 0.2 L/hour for TPD. The mean dialysate dextrose was 1.9 +/- 0.5 g/dL for both. The creatinine clearances were 9 +/- 2 versus 10 +/- 3 mL/minute, the urea nitrogen clearances 19 +/- 3 versus 20 +/- 3 mL/minute, and phosphate clearances 10 +/- 3 versus 11 +/- 3 mL/minute for IPD and TPD, respectively (all not different). The ultrafiltration rates were 2.9 +/- 0.9 mL/minute on IPD and 3.3 +/- 1.6 mL/minute on TPD (not different). On both IPD and TPD the clearances of urea nitrogen, creatinine, and phosphate for the 2 patients with high-average D/P creatinine were higher than for the 4 patients with low-average D/P creatinine.


CONCLUSIONS
When the dialysate flow rate is controlled and a TPD prescription of 1 L reserve and tidal volumes is used, the small molecule clearances on IPD are similar to those on TPD.
Piraino
B
B
Department of Medicine, University of Pittsburgh, Pennsylvania.
Bender
F
F
Bernardini
J
J
D001806:Blood Urea Nitrogen; D003404:Creatinine / Q000378:metabolism; D015314:Dialysis Solutions; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000378:metabolism / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis / Q000379:methods*; D010531:Peritoneal Dialysis, Continuous Ambulatory; D010537:Peritoneum / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D013997:Time Factors
D015314:Dialysis Solutions; D010710:Phosphates; D003404:Creatinine; D011188:Potassium