How to define and quantify Haemodiafiltration, Tattersal · Ficheux. KI 2000 57 . Ficheux. KI 2000...
Transcript of How to define and quantify Haemodiafiltration, Tattersal · Ficheux. KI 2000 57 . Ficheux. KI 2000...
What uraemic toxins?
RR (%, mean ± SD, n = 14) of the water-soluble compo unds (A: urea, B: uric acid), protein-bound solutes (C: hippuric acid, D: indole acetic a cid, E: indoxylsulphate, F: p-
cresylsulphate) and LMWPs (G: b2-microglobulin, H: cystatin C, I: myoglobin, J: retinol-binding protein) in HD, pre-HDF and post-HDF.
Meert N et al. Nephrol. Dial. Transplant. 2011;26:2 624-2630
Box-plot representation of reduction percentages in kappa (KL) and lambda (LL) FLC after correction for fluid removal, for HD and HDF treatm ent groups.
Granger Vallée A et al. Nephrol. Dial. Transplant. 2011;26:3627-3633
© The Author 2011. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. For Permissions, please e-mail: [email protected]
Serum FLC reduction percentage corrected for fluid removal (a) and clearance (b) as a function of substitution volume in post-dilution HD F. Corrected reduction percentages show
a linear correlation, both for κ (r = 0.61; P = 0.04) and λ (r = 0.58; P < 0.05) FLC, while clearances show a trend in the same direction witho ut reaching statistical significance ( κ, r =
0.55; P = 0.07 and λ, r = 0.53; P = 0.07).
Granger Vallée A et al. Nephrol. Dial. Transplant. 2011;26:3627-3633
© The Author 2011. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. For Permissions, please e-mail: [email protected]
Serum phosphate in hemodialysis and hemodiafiltrati on cohorts.
Davenport A et al. Nephrol. Dial. Transplant. 2010; 25:897-901
© The Author 2009. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. For Permissions, please e-mail: [email protected]
Cheung et al. J Am Soc Nephrol 17: 546–555, 2006.
HEMO study
http://www.ncbi.nlm.nih.gov/corecgi/tileshop
/tileshop.fcgi?p=PMC3&id=626080&s=14&r=3
&c=1
HEMO study, infections mortality
Cheung Clin J Am Soc Nephrol. 2008 January; 3(1): 69–77
Senji Okuno Nephrol Dial Transplant (2009) 24: 571–577
HDF and survival
Vilar E Clin J Am Soc Nephrol. 2009 Dec;4(12):1944-53
Contrast study
April 2012
Diffusion
Convection / filtration
Temperature, velocity and energy
E = Average energy
T = Absolute temperature
m= mass
V = average velocity
K = Boltzmann’s constant
Einstein’s theory of diffusion
Albert Einstein considered diffusion to be a consequence of Brownian
motion of solute molecules. The process could be predicted
mathematically from temperature, radius of the molecule and the
viscosity of the solute.
tr
TKDtx b
ηπ322 ==
Where x is the average distance travelled by a molecule in time t, D is the
diffusivity. Kb is Boltzmann’s constant linking temperature to kinetic energy,
T is the absolute temperature, r is the effective radius of the molecule and ȃ
is the viscosity of the solution.
Brownian motion
Average absolute distance moved is proportional to
the square toot of time and diffusion coefficient
Urea and B-2-Microglobulin
B-2-M
M.Wt = 12800
Urea
M.Wt = 60Diffusion 15 x
Diffusion 1 x
Diffusion
M.Wt
Sieving
SC=1
SC=0
Sieving
SC=0.5
Convection / filtration
Pure convection
Convection + diffusion
Convection + diffusion
Jaffrin 1995
20 0083.043.0 QfQfKKt ++=
Waniewski 1979
QfQb
KSKKt
−+= 00 1
Waniewski 2003
Diffusion and convection
Ficheux. KI 2000 57
Ficheux. KI 2000 57
Ficheux. KI 2000 57
High-flux backfiltration
Super-flux
Recommendation
Definitions
• HDF requires effective ultrafiltration at least
20% of blood flow rate.
• Effective ultrafiltration takes account of pre-
dilution.
– In pre-dilution HDF, UF rate needs to be 2-3 times
greater compared to post-dilution.
• The HDF component is quantified as the total
effective volume ultrafiltered.
Effective ultrafiltration
Qpw = Qb x (1-Hct) x (1-Pct)
DF = Qpw / (Qpw + Qinf)
Effective UF= actual UF x DF
Out of scope
• Mid-dilution
• Internal filtration
For these modes, manufacturers should indicate effective ultrafiltration rates for range of likely flow conditions.
• How to normalize (surface area, urea distribution volume)
• “Adequate dose”.