title: Phosphorus kinetics during hemodiafiltration: analysis using a pseudo-one-compartment model.
abstract: OBJECTIVE
  On-line hemodiafiltration (HDF) has been previously shown to result in modest reductions in predialysis serum phosphorus concentration compared with conventional hemodialysis (HD); however, understanding of phosphorus kinetics during these therapies remains limited.
  
  
  METHODS
  Previously published phosphorus kinetic data during HDF and HD were analyzed using a pseudo-one-compartment kinetic model. Phosphorus mobilization clearance (KM) and dialyzer phosphorus clearance (Kd) were simultaneously estimated from measured predialysis and postdialysis serum phosphorus concentrations and total removed phosphorus during each treatment.
  
  
  RESULTS
  KM varied among patients between 53 and 173 ml/min. Values of KM during HDF (105 ± 34, mean ± standard deviation, ml/min) and HD (112 ± 44 ml/min) were not different (p = 0.5); however, Kd during HDF (175 ± 23 ml/min) was higher (p = 0.01) than during HD (160 ± 14 ml/min).
  
  
  CONCLUSIONS
  A pseudo-one-compartment kinetic model is useful for the analysis of phosphorus kinetic data during HDF. Lower predialysis serum phosphorus concentrations during HDF are likely due to increased extracorporeal phosphorus clearance.
authors: Medical Products (Renal), Baxter Healthcare Corporation, Deerfield, IL 60015, USA. ken_leypoldt@baxter.com
authors: John K
authors: JK
authors: Leypoldt
authors: Baris U
authors: BU
authors: Agar
authors: Alp
authors: A
authors: Akonur
authors: Bruce F
authors: BF
authors: Culleton
mesh_terms: D000465:Algorithms; D017583:Hemodiafiltration / Q000379:methods; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000628:therapy; D007700:Kinetics; D008954:Models, Biological; D010758:Phosphorus / Q000097:blood*
chemical_list: D010758:Phosphorus