Determinants of Hemodialysis Performance:Modeling Fluid and Solute Transport in Hollow-Fiber Dialyzers
- 2 Downloads
Hemodialysis constitutes the lifeline of patients with end stage renal disease, yet the parameters that affect hemodialyzer performance remain incompletely understood. We developed a computational model of mass transfer and solute transport in a hollow-fiber dialyzer to gain greater insight into the determinant factors. The model predicts fluid velocity, pressure, and solute concentration profiles for given geometric characteristics, membrane transport properties, and inlet conditions. We examined the impact of transport and structural parameters on uremic solute clearance by varying parameter values within the constraints of standard clinical practice. The model was validated by comparison with published experimental data. Our results suggest solute clearance can be significantly altered by changes in blood and dialysate flow rates, fiber radius and length, and net ultrafiltration rate. Our model further suggests that the main determinant of the clearance of unreactive solutes is their diffusive permeability. The clearance of protein-bound toxins is also strongly determined by blood hematocrit and plasma protein concentrations. Results from this model may serve to optimize hemodialyzer operating conditions in clinical practice to achieve better clearance of pathogenic uremic solutes.
There are nearly 500,000 patients in the USA on kidney dialysis, and a large percentage of these patients use hollow-fiber dialyzers; yet, there is much room for improvement of their performance. To address this issue, we developed a computational model to understand the transport properties of hollow-fiber dialyzers and their effects on clearance of toxins. This study is inspired by the early work of Robert S. Langer in the area of immobilized heparinase in extracorporeal devices, and we continue to look to him as an inspiration for translational research to—in his words—“make a positive impact to improve the quality of life”.
KeywordsHemodialysis Computational Modeling Solute transport Uremic Toxins Albumin binding
We thank Dr. Belghasem in the Department of Pathology and Laboratory Medicine at Boston University for his contribution to the summary figure. We also thank James K. Goebel in the Engineering Information Technology Office at Boston University for his help in setting up the COMSOL Batch mode.
This project was funded by National Institutes of Health (NIH) grants R01-HL132325 and R01-CA175382 to VCC, NIH grant T32 HL007224 to OA, and Boston University’s College of Engineering Distinguished Professorship support to JYW.
- 7.Kolachalama VB, Shashar M, Alousi F, Shivanna S, Rijal K, Belghasem ME, et al. Uremic solute-aryl hydrocarbon receptor-tissue factor axis associates with thrombosis after vascular injury in humans. J Am Soc Nephrol. 2018;29(3):1063–72.Google Scholar
- 23.Annan K. Mathematical modeling for hollow fiber dialyzer: blood and HCO 3 - -dialysate flow characteristics. IJPAM. 2012;79:425–52.Google Scholar
- 24.Landis, E.M. and J.F. Pappenheimer, Exchange of substances through the capillary walls, in Handbook of physiology. 1963, American Physiological Society: Washington, DC. p. pp. 961-1034.Google Scholar
- 25.Hall, J.E., Guyton and Hall textbook of medical physiology. 13 ed. 2016, Philadelphia, PA: Elsevier.Google Scholar
- 26.Pallone TL, Petersen J. A mathematical model of continuous arteriovenous hemofiltration predicts performance. ASAIO Trans. 1987;33(3):304–8.Google Scholar
- 27.Lightfoot EN. Transport phenomena and living systems—biomedical aspects of momentum and mass transport. New York City, NY: Wiley; 1974.Google Scholar
- 28.Preston, B.N., et al., Diffusion of dextran at intermediate concentrations. Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, 1982. 78(4): p. 1209-1221.Google Scholar
- 30.Liao Z, et al. Measurement of hollow fiber membrane transport properties in hemodialyzers. J Membrane Sci. 2005;256(1):176–83.Google Scholar
- 39.Baxter, Manufacturer’s Specification Sheet of CT190G Dialyzer. . Available from: https://www.baxter.com/assets/downloads/al09086-cellulosic-brochure-final.pdf.
- 43.National Kidney Foundation. KDOQI Clinical Practice Guideline for Hemodialysis Adequacy. update. Am J Kidney Dis, 2015. 2015;66(5):884–930.Google Scholar
- 49.Nisha R, et al. Biochemical evaluation of creatinine and urea in patients with renal failure undergoing hemodialysis. J Clin Path Lab Med. 2017;1:1–5.Google Scholar