A new technique for low-volume continuous sampling of spent dialysate: a validation study

  • Rafael Bueno Orcy
  • Maria Fernanda Antunes
  • Jean Pierre Oses
  • Maristela BöhlkeEmail author
Original Article Artificial Kidney / Dialysis


The measure of hemodialysis (HD) adequacy recommended nowadays by most guidelines, Kt/V-urea, presents significant drawbacks. Direct dialysis quantification (DDQ) through total dialysate collection (TDC), considered the gold standard measure of HD adequacy, is cumbersome, which precludes its widespread use in clinical practice. The present study aims to validate a low-volume continuous sampling of spent dialysate (CSSD). Cross-sectional study carried out at a university hospital. Throughout 4-h hemodialysis sessions, urea removal was measured by three DDQ methods: TDC, CSSD, and fractional sampling of dialysate (FSD). The primary outcome was the comparison between the total mass of urea removed measured by TDC and the dialysate sampling techniques. The comparison between urea distribution volume (UDV) estimated by anthropometric method and through DDQ was a secondary outcome. The analysis was done through linear regression and Bland–Altman concordance method. Twenty HD sessions were studied. The mean amount of urea collected in TDC and calculated from the 40-mL sample of CSSD were 33.70 ± 11.70 g and 33.90 ± 11.70 g, respectively [r 0.96, p < 0.0001; bias − 0.2 (95% CI − 1.8 to 1.4); limits of agreement − 6.8 to 6.4]. The anthropometric measure, when compared with DDQ method, underestimated UDV in patients with smaller body size. This new simple, inexpensive, and small volume CSSD technique can provide accurate information about the total amount of solutes removed by hemodialysis.


Hemodialysis Adequacy Solute removal Direct dialysis quantification 


Author contributions

ORB and BM contributed to conception and design, analysis and interpretation of data, drafting and revising the article; OJP and AMF contributed to design, acquisition of data, analysis and interpretation of data, and revising the article.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


  1. 1.
    Kolff WJ, Berk HTJ, ter Welle M, van der Ley AJW, van Dijk EC, van Noordwijk J. The artificial kidney, a dialyzer with a great area. Acta Med Scand. 1944;117:121–8.CrossRefGoogle Scholar
  2. 2.
    Lowrie EG, Laird NM, Parker TF, Sargent JA. Effect of the hemodialysis prescription of patient morbidity: report from the National Cooperative Dialysis Study. N Engl J Med. 1981;305:1176–81.CrossRefGoogle Scholar
  3. 3.
    National Kidney Foundation. KDOQI clinical practice guideline for hemodialysis adequacy: 2015 update. Am J Kidney Dis. 2015;66:884–930.CrossRefGoogle Scholar
  4. 4.
    Quellhorst E. Long-term follow-up in chronic hemofiltration. Int J Artif Organs. 1983;6:115–20.CrossRefGoogle Scholar
  5. 5.
    Kramer P, Bohler J, Kehr A, et al. Intensive care potential of continuous arteriovenous hemofiltration. Trans Am Soc Artif Intern Organs. 1982;28:28–32.Google Scholar
  6. 6.
    Man NK, Granger A, Rondon- Nucete M, Zingraff J, Jungers P, Sausse A, Funck-Brentano JL. One year follow-up of short dialysis with a membrane highly permeable to middle molecules. Proc EDTA. 1973;10:236–46.Google Scholar
  7. 7.
    Vanholder R, Glorieux G, Eloot S. Once upon a time in dialysis: the last days of Kt/V? Kidney Int. 2015;88:460–5.CrossRefGoogle Scholar
  8. 8.
    Spalding EM, Chamney PW, Farrington K. Phosphate kinetics during hemodialysis: evidence for biphasic regulation. Kidney Int. 2002;61:655–67.CrossRefGoogle Scholar
  9. 9.
    Malchesky PS, Ellis P, Nosse C, Magnusson M, Lankhorst B, Nakamoto S. Direct quantification of dialysis. Dial Transpl. 1982;11:42–9.Google Scholar
  10. 10.
    Gamed LJ, Rittau M, McCready W, Canaud B. Urea kinetic modelling by partial dialysate collection. Int J Artif Organs. 1989;12:96–102.CrossRefGoogle Scholar
  11. 11.
    Ing TS, Yu AW, Wong FKM, Rafiq M, Zhou FQ, Daugirdas JT. Collection of a representative fraction of total pent hemodialysate. Am J Kidney Dis. 1995;5:810–2.CrossRefGoogle Scholar
  12. 12.
    Charytan C, Gupta B, Meindel N, Spinowitz B. Fractional direct dialysis quantification: a new approach for prescription and monitoring hemodialysis therapy. Kidney int. 1996;50:1845–9.CrossRefGoogle Scholar
  13. 13.
    Argiles A, Ficheux A, Thomas M, Bosc JY, Kerr PG, LoRilo R, Flavier JL, et al. Precise quantification of dialysis using continuous sampling of spent dialysate and total dialysate volume measurement. Kidney Int. 1997;52:530–7.CrossRefGoogle Scholar
  14. 14.
    Kanagasundaram NS, Larive B, Paganini EP, for the Picard Study Group. A fractional dialysate collection method to estimate solute removal in continuous venovenous hemodialysis. Kidney Int. 2000;58:2579–84.CrossRefGoogle Scholar
  15. 15.
    Daugirdas JT. Second generation logarithmic estimates of single-pool variable volume Kt/V: an analysis of error. J Am Soc Nephrol. 1993;4:1205–13.Google Scholar
  16. 16.
    Goldau R. Clinical evaluation of novel methods to determine dialysis parameters using conductivity cells. Wurzburg. Thesis [Doctoral Thesis in Natural Sciences]—Bayerischen Julius-Maximilians-Universitat Wurzburg; 2002.Google Scholar
  17. 17.
    Block GA, Klassen PS, Lazarus JM, Ofsthun N, Lowrie EG, Chertow GM. Mineral metabolism, mortality, and morbidity in maintenance hemodialysis. J Am Soc Nephrol. 2004;15:2208–18.CrossRefGoogle Scholar
  18. 18.
    Orcy R, Antunes MF, Schiller T, Seus T, Böhlke M. Aerobic exercise increases phosphate removal during hemodialysis: a controlled trial. Hemodial Int. 2014;18:450–8.CrossRefGoogle Scholar
  19. 19.
    Eknoyan G, Beck GJ, Cheung AK, Daugirdas JT, Greene T, Kusek JW, et al. for the Hemodialysis (HEMO) Study Group: effect of dialysis dose and membrane flux in maintenance hemodialysis. N Engl J Med. 2002;347:2010–9.CrossRefGoogle Scholar
  20. 20.
    Depner T, Daugirdas J, Greene T, Allon M, Beck G, Chumlea C, et al, for the Hemodialysis Study Group. Dialysis dose and the effect of gender and body size on outcome in the HEMO Study. Kidney Int. 2004;65:1386–94.CrossRefGoogle Scholar
  21. 21.
    Daugirdas JT. We underdialyze women and smaller patients. Semin Dial. 2016;29:303–5.CrossRefGoogle Scholar
  22. 22.
    Sarkar SR, Kuhlmann MK, Kotanko P, et al. Metabolic consequences of body size and body composition in hemodialysis patients. Kidney Int. 2006;70:1832–9.CrossRefGoogle Scholar

Copyright information

© The Japanese Society for Artificial Organs 2019

Authors and Affiliations

  1. 1.Postgraduate Program in Health and BehaviorCatholic University of PelotasPelotasBrazil
  2. 2.Dialysis and Renal Transplantation Unit, São Francisco de Paula University HospitalCatholic University of PelotasPelotasBrazil
  3. 3.Department of PhysiologyFederal University of PelotasPelotasBrazil

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