title: A comparison of clearances on tidal peritoneal dialysis and intermittent peritoneal dialysis.
abstract: 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.
authors.affiliation: Department of Medicine, University of Pittsburgh, Pennsylvania.
authors.forename: B
authors.initials: B
authors.lastname: Piraino
authors.forename: F
authors.initials: F
authors.lastname: Bender
authors.forename: J
authors.initials: J
authors.lastname: Bernardini
mesh_terms: 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
chemical_list: D015314:Dialysis Solutions; D010710:Phosphates; D003404:Creatinine; D011188:Potassium