title: Body composition monitoring-derived urea distribution volume in children on chronic hemodialysis.
abstract: BACKGROUND
  Modern hemodialysis (HD) machines are able to measure ionic dialysance online and thereby continuously monitor Kt/V. The accuracy of measurement depends on the input of the correct urea distribution volume (V), available from anthropometric equations and body composition monitoring (BCM). The latter method, however, has not been validated in children.
  
  
  METHODS
  We compared V determined by BCM to that calculated using four different anthropometric formulas (Morgenstern, Mellits and Cheek, Hume-Weyers and Watson equations) in 23 pediatric HD patients. We also compared online Kt/V using BCM-derived V with the Kt/V calculated from pre- and post-dialytic urea concentrations using the single-pool second-generation Daugirdas equation.
  
  
  RESULTS
  The V calculated by the Morgenstern equation was similar to that derived by BCM, with a mean difference of -0.7% (95% limits of agreement -11.7 to 10.3%). In contrast, the V calculated by the other equations was 5.4, 6.2 and 18%, respectively higher than the BCM-derived V. The mean difference between Kt/V calculated using the Daugirdas equation and online Kt/V determination based on BCM-derived V data was 0.10 (95% limits of agreement -0.50 to 0.70%).
  
  
  CONCLUSIONS
  In our pediatric HD patients the V measured by BCM was in agreement with that calculated using the Morgenstern equation, which is the only equation which has been validated to date in children on dialysis. Online determination of Kt/V using a BCM-derived V largely agreed with that calculated by the Daugirdas equation. We therefore conclude that the former approach is suitable for frequent online assessment of dialytic small solute clearance.
authors.affiliation: Nephrology Dialysis Transplantation Children's Unit, University Hospital Hautepierre, 67098, Strasbourg, France.
authors.forename: Ariane
authors.initials: A
authors.lastname: Zaloszyc
authors.affiliation: Nephrology Dialysis Transplantation Children's Unit, University Hospital Hautepierre, 67098, Strasbourg, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Fischbach
authors.affiliation: Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany.
authors.forename: Betti
authors.initials: B
authors.lastname: Schaefer
authors.affiliation: Institute of Medical Biometry and Informatics, Im Neuenheimer Feld 305, 69120, Heidelberg, Germany.
authors.forename: Lorenz
authors.initials: L
authors.lastname: Uhlmann
authors.affiliation: Pediatric Nephrology, Hôpital Necker-Enfants Malades, 75015, Paris, France.
authors.forename: Rémi
authors.initials: R
authors.lastname: Salomon
authors.affiliation: Pediatric Nephrology, Hôpital Necker-Enfants Malades, 75015, Paris, France.
authors.forename: Saoussen
authors.initials: S
authors.lastname: Krid
authors.affiliation: Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany. Claus.Peter.Schmitt@med.uni-heidelberg.de.
authors.forename: Claus Peter
authors.initials: CP
authors.lastname: Schmitt
mesh_terms: D000293:Adolescent; D000886:Anthropometry / Q000379:methods; D001823:Body Composition; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007676:Kidney Failure, Chronic / Q000097:blood / Q000378:metabolism* / Q000628:therapy; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods*; D006435:Renal Dialysis; D014508:Urea / Q000097:blood / Q000378:metabolism*
chemical_list: D014508:Urea
keywords: Children; Impedance analysis; Online Kt/V; Pediatric dialysis; Urea distribution volume