title: Use of ionic dialysance to calculate Kt/V in pediatric hemodialysis.
abstract: Online clearance (OLC) monitor measures conductivity difference between dialysate entering and leaving the dialyser. Derived ionic dialysance (ID) represents effective urea clearance from which Kt/V is calculated, allowing Kt/V monitoring at every treatment without blood sampling. We tested ID accuracy in children and provide recommendations for its use. Using Fresenius machines 2008 K with built-in OLC monitors, we studied 45 hemodialysis (HD) sessions and 168 calculated Kt/V results in 11 patients. Urea distribution volume (V), needed to calculate Kt/V from ID, was estimated using three methods: Mellits and Cheek (MC), KDOQI recommended total body water nomograms (TBWN) and OLC-derived independent from tested HD sessions. Reference spKt/V from pre- and post-HD BUN (Daugirdas) was compared with Kt/V calculated from ID using three different estimated V's. ID was accurate in calculating Kt/V in children when V derived from OLC was used (P = 0.42), with absolute error 0.14 ± 0.12. If TBWN-derived V was used, Kt/V was consistently underestimated by 0.32 ± 0.22. TBWN-derived V can still be recommended for use with OLC for monitoring trend in Kt/V, if underestimation of spKt/V of average 0.3 is accounted for. MC-derived V results in even greater underestimation of spKt/V and therefore cannot be recommended for use with OLC.
authors.affiliation: Pediatric Nephrology, Oklahoma University Health Sciences Center, Oklahoma City, Oklahoma, USA. olivera-couloures@ouhsc.edu
authors.forename: Olivera
authors.initials: O
authors.lastname: Marsenic
authors.forename: Kristi
authors.initials: K
authors.lastname: Booker
authors.forename: Kathleen
authors.initials: K
authors.lastname: Studnicka
authors.forename: Donna
authors.initials: D
authors.lastname: Wilson
authors.forename: Ann
authors.initials: A
authors.lastname: Beck
authors.forename: Tiffany
authors.initials: T
authors.lastname: Swanson
authors.forename: Dwayne
authors.initials: D
authors.lastname: Henry
authors.forename: Martin
authors.initials: M
authors.lastname: Turman
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D015312:Hemodialysis Solutions / Q000737:chemistry; D006801:Humans; D007477:Ions / Q000737:chemistry; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods; D006435:Renal Dialysis / Q000295:instrumentation* / Q000379:methods*; D014508:Urea / Q000097:blood / Q000378:metabolism*; D055815:Young Adult
chemical_list: D015312:Hemodialysis Solutions; D007477:Ions; D014508:Urea