Nephrol Dial Transplant (2002) 17: 17-21
© 2002 European Renal Association-European Dialysis and Transplant Association
SECTION II: Haemodialysis adequacy
II.1 Haemodialysis dose quantification: small solutes
AbstractGuideline II.1.1
A. Urea is the most suitable marker for the uraemic toxins in the range of the low MW solutes.
(Evidence level: B)
Guideline II.1.2
A. HD dose should be expressed in terms of equilibrated Kt/V (eKt/V) with the rate equation based on the regional blood flow two-pool urea kinetic model [41]:
eKt/V=spKt/V–(0.6xspKt/V/T)+0.03
(with an arteriovenous access)
eKt/V=spKt/V-(0.47xspKt/V/T)+0.02
(with a venovenous access, i.e. absence of cardiopulmonary recirculation).
(Evidence level: B)
C. The value for the single-pool Kt/V (spKt/V) should be derived from the formal single-pool variable volume urea kinetic model (spUKM) [42]. As an alternative, the natural logarithm equation provides the most accurate estimate of spKt/V [43]:
spKt/V=-ln (Ct/Co–0.008xT) +(4–3.5xCt/Co)xdBW/BW
where: K=dialyzer clearance (ml/min); V=urea distribution volume (ml); t, T=treatment time (in minutes and hours, respectively); Co, Ct=start and end-session urea (or BUN) concentration; dBW=intradialytic weight loss (kg); BW=end-session body weight (kg).
D. Sampling Ct 30 min after the end of the session and applying the spKt/V equation gives the eKt/V value [44] (see also Guideline II.4.1).
Guideline II.1.3
A. Based on the available evidence the minimum prescribed HD dose per session for a thrice-weekly schedule should be:
urea eKt/V
1.20 (sp Kt/V
1.4).
Twice-weekly schedules are not recommended.
(Evidence level: B)