title: Effects of high blood flow and high pre-dilution replacement fluid rates on small solute clearances in hemofiltration.
abstract: OBJECTIVE
  In pre-dilution hemofiltration (HF), solute clearance is less than the HF rate. While the amount of this loss is predictable, it has not been validated in high-volume HF associated with high blood flow rates.
  
  
  METHODS
  Using isovolemic pre-dilution HF, we studied small solute clearances using combinations of blood flow (Q(B); 150, 250, 350, 450 ml/min) and replacement fluid (RF) flow (Q(RF); 2, 4, 6 l/h) to determine clearance losses we entitled 'measured efficiency' (E(M)). E(M) was compared to predicted efficiency (E(P)) = (Q(B)/Q(B) + Q(RF)).
  
  
  RESULTS
  Pre-dilution produced E(M) values of 61-93%. Increases in Q(B) for any Q(RF) and decreases in Q(RF) for any Q(B) increased E(M) over a wide range of Q(B) and Q(RF). E(P) was equivalent to E(M).
  
  
  CONCLUSIONS
  In high-volume pre-dilution HF, E(P) can be used to determine E(M) across a broad range of Q(B) and Q(RF) values. Higher Q(RF) requires higher Q(B) to minimize the attenuating effects of pre-dilution on clearance.
authors.affiliation: Section of Nephrology, Rush University Medical Center, Chicago, Ill., USA. Casey_Gashti @ rush.edu
authors.forename: Casey N
authors.initials: CN
authors.lastname: Gashti
authors.forename: Roger A
authors.initials: RA
authors.lastname: Rodby
authors.forename: Zhongping
authors.initials: Z
authors.lastname: Huang
authors.forename: Dayong
authors.initials: D
authors.lastname: Gao
authors.forename: Weiming
authors.initials: W
authors.lastname: Zhang
mesh_terms: D003404:Creatinine / Q000378:metabolism*; D006440:Hemofiltration; D006801:Humans; D007700:Kinetics; D017597:Renal Blood Flow, Effective; D014508:Urea / Q000378:metabolism*
chemical_list: D014508:Urea; D003404:Creatinine