TY - JOUR
T1 - Effect of ultrafiltration on peripheral urea sequestration in haemodialysis patients
AU - Schneditz, Daniel
AU - Zaluska, Wojciech T.
AU - Morris, Alice T.
AU - Levin, Nathan W.
N1 - Funding Information:
Acknowledgements. We thank The Dina and Raphael Recanati Foundation for financial support and In-Line Diagnostics, Riverdale, Utah, and Fresenius Medical Care, Division of Innovation & Technology for Hemodialysis, Bad Homburg, Germany for technical support of this work.
PY - 2001
Y1 - 2001
N2 - Background. Ultrafiltration (UF) is assumed to enhance urea removal during haemodialysis (HD) because of convective transport and because of contraction of urea distribution volume. However, UF-induced blood volume reduction has been hypothesized to enhance peripheral urea sequestration and post-dialysis urea rebound (PDUR), possibly reducing HD effectiveness. The effect of UF on PDUR was investigated in this study. Methods. Nine HD patients were studied on two subsequent treatment days. The first HD was performed with UF (UF-rate = 0.78±0.27 1/h), and the second treatment without UF. Serial measurements of serum water urea nitrogen concentration, arterial blood pressures (BP), and relative blood volume changes (ΔBV%) were obtained over the duration of HD. Results. BP and ΔBV% decreased with UF (BPsys= -9%, BPdia = -8%, BPmean = -9%, ΔBV% = -15%) but increased or remained unchanged without UF (BPsys = 9%, BPdia = 12%, BPmean = 11%, ΔBV% = 1%). PDUR was 28.6±9.6% without UF, and increased in every single patient with UF (40.7±13.2%, P<0.01). Modelled perfusion of the peripheral low-flow compartment decreased from 1.45±0.54 1/min without UF to 0.91±421/min with UF (P<0.05), thereby explaining an enhanced two-compartment effect and increasing PDUR. Conclusion. The significant increase in the two-compartment effect of urea kinetics observed in current HD accompanied by UF can be explained by compensatory, intradialytic blood flow redistribution induced by blood volume reduction. Because of the link between UF and blood flow, limited solute clearance treatment modes that optimize fluid removal such as variable UF will also have favourable effects on delivered dose of dialysis.
AB - Background. Ultrafiltration (UF) is assumed to enhance urea removal during haemodialysis (HD) because of convective transport and because of contraction of urea distribution volume. However, UF-induced blood volume reduction has been hypothesized to enhance peripheral urea sequestration and post-dialysis urea rebound (PDUR), possibly reducing HD effectiveness. The effect of UF on PDUR was investigated in this study. Methods. Nine HD patients were studied on two subsequent treatment days. The first HD was performed with UF (UF-rate = 0.78±0.27 1/h), and the second treatment without UF. Serial measurements of serum water urea nitrogen concentration, arterial blood pressures (BP), and relative blood volume changes (ΔBV%) were obtained over the duration of HD. Results. BP and ΔBV% decreased with UF (BPsys= -9%, BPdia = -8%, BPmean = -9%, ΔBV% = -15%) but increased or remained unchanged without UF (BPsys = 9%, BPdia = 12%, BPmean = 11%, ΔBV% = 1%). PDUR was 28.6±9.6% without UF, and increased in every single patient with UF (40.7±13.2%, P<0.01). Modelled perfusion of the peripheral low-flow compartment decreased from 1.45±0.54 1/min without UF to 0.91±421/min with UF (P<0.05), thereby explaining an enhanced two-compartment effect and increasing PDUR. Conclusion. The significant increase in the two-compartment effect of urea kinetics observed in current HD accompanied by UF can be explained by compensatory, intradialytic blood flow redistribution induced by blood volume reduction. Because of the link between UF and blood flow, limited solute clearance treatment modes that optimize fluid removal such as variable UF will also have favourable effects on delivered dose of dialysis.
KW - Haemodialysis
KW - Isovolaemic haemodialysis
KW - Post-dialysis urea rebound
KW - Relative blood volume
KW - Ultrafiltration
KW - Urea kinetic modelling
UR - https://www.scopus.com/pages/publications/0035002459
U2 - 10.1093/ndt/16.5.994
DO - 10.1093/ndt/16.5.994
M3 - Article
C2 - 11328906
AN - SCOPUS:0035002459
SN - 0931-0509
VL - 16
SP - 994
EP - 998
JO - Nephrology Dialysis Transplantation
JF - Nephrology Dialysis Transplantation
IS - 5
ER -