Principles and Biophysics of Dialysis

Sargent, John; Gotch, Frank A.

doi:10.1007/978-94-009-9327-3_3

Cited by 58 publications

(84 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Blood passes through the fibres leaving the toxins trapped behind [40]. The rate at which toxins are removed from the blood is dependent upon blood flow rate due to solute concentrations, mass, and the area of diffusion [41]. To determine the individual filtration requirements, toxins are isolated according to Fick's Law:…”

Section: Haemodialysismentioning

confidence: 99%

“…where the flux of toxins J flowing over a distance of dx is proportional to the difference in concentration dc and the area of diffusion A. Diffusivity D is a constant value with units of cm 2 /sec that results from balancing the rest of the equation at a given temperature [41]. Once the toxins are isolated by diffusion, a cleaning solution known as dialysate flushes the waste material away from the dialyser fibres [40].…”

Section: Haemodialysismentioning

confidence: 99%

See 1 more Smart Citation

Breath Ammonia Analysis: Clinical Application and Measurement

Hibbard

Killard

2011

Critical Reviews in Analytical Chemistry

123

View full text Add to dashboard Cite

Section: Haemodialysismentioning

confidence: 99%

Section: Haemodialysismentioning

confidence: 99%

Breath Ammonia Analysis: Clinical Application and Measurement

Hibbard

Killard

2011

Critical Reviews in Analytical Chemistry

123

View full text Add to dashboard Cite

“…and after integration of equation 10 and solving it for the mass flux J, clearance K can then be written as a function of the mass transfer coefficient K 0 (m/s), which is the reciprocal of total resistance R 0 , and of the logarithmic mean concentration difference ∆C lm [17]: R B , R M , and R D represent the blood-side, membrane and dialysate-side resistance, respectively. ∆x B and ∆x D symbolize a characteristic distance for diffusion in the blood and dialysate domain, while ∆x M is the membrane thickness.…”

Section: Calibration and Validation Of The Diffusivitiesmentioning

confidence: 99%

Computational fluid and mass transport on macro and micro scales in an artificial kidney

Eloot¹,

Verdonck²

2005

Modelling in Medicine and Biology VI

View full text Add to dashboard Cite

The evaluation of dialyzer geometry was obtained by investigating transport processes and fluid properties inside the dialyzer. With computational fluid dynamics (CFD), a macroscopic as well as a microscopic model of the dialyzer was developed.Blood and dialysate flow distributions were calculated in a macroscopic numerical model of a low flux hollow fiber dialyzer. Computer simulations were compared to flow field SPECT visualizations (Single Photon Emission Computerized Tomography). The derived local fluid velocities were further implemented in a three-dimensional microscopic computer model of a single hollow fiber with its surrounding membrane and dialysate compartment. Different equations govern blood and dialysate flow (Navier-Stokes), radial filtration flow (Darcy), and solute transport (convection-diffusion). Blood was modeled as a non-Newtonian fluid with a viscosity varying both in radial and axial direction. Dialysate flow was assumed as a laminar Newtonian flow with constant viscosity. The permeability characteristics of the asymmetrical polysulphone membrane were calculated from laboratory tests for forward and backfiltration.The model was calibrated and validated in order to accurately calculate water removal as well as mass transport of small (urea) and middle molecules (vitamin B12 and inulin). Furthermore, the present microscopic CFD model was used to investigate the impact on the mass removal of dialyzer geometry and flow distributions.

show abstract

“…When c b / is near zero (i.e., far from saturation of the SAF), the unsteady term is removed from the mass conservation equation and the wall boundary condition is simplified: Finally we determined the antibody removal rate R (nmol/min) (R ) Q(c i -c o )) and the antibody clearance K (mL/min) (K ) R/c i ) Q(1 -c o /c i )). The clearance represents the volume of antibody solution completely depleted of antibodies per unit time, and is a more useful indicator of SAF performance than the antibody removal rate because the clearance depends only on the percent reduction in antibody concentration and is independent of the actual antibody concentration level in the blood (33). For c b / equal to zero, the governing equations are linear with respect to the free antibody concentration, and hence c o is linearly proportional to c i and the clearance is independent of c i .…”

Section: Antibody Transport Modelmentioning

confidence: 99%

Mathematical and Experimental Analyses of Antibody Transport in Hollow‐Fiber‐Based Specific Antibody Filters

Hout

Federspiel

2003

Biotechnology Progress

View full text Add to dashboard Cite

We are developing hollow fiber-based specific antibody filters (SAFs) that selectively remove antibodies of a given specificity directly from whole blood, without separation of the plasma and cellular blood components and with minimal removal of plasma proteins other than the targeted pathogenic antibodies. A principal goal of our research is to identify the primary mechanisms that control antibody transport within the SAF and to use this information to guide the choice of design and operational parameters that maximize the SAF-based antibody removal rate. In this study, we formulated a simple mathematical model of SAF-based antibody removal and performed in vitro antibody removal experiments to test key predictions of the model. Our model revealed three antibody transport regimes, defined by the magnitude of the Damköhler number Da (characteristic antibody-binding rate/characteristic antibody diffusion rate): reaction-limited (Da e 0.1), intermediate (0.1 < Da < 10), and diffusion-limited (Da g 10). For a given SAF geometry, blood flow rate, and antibody diffusivity, the highest antibody removal rate was predicted for diffusion-limited antibody transport. Additionally, for diffusion-limited antibody transport the predicted antibody removal rate was independent of the antibody-binding rate and hence was the same for any antibody-antigen system and for any patient within one antibody-antigen system. Using SAF prototypes containing immobilized bovine serum albumin (BSA), we measured anti-BSA removal rates consistent with transport in the intermediate regime (Da ∼3). We concluded that initial SAF development work should focus on achieving diffusion-limited antibody transport by maximizing the SAF antibody-binding capacity (hence maximizing the characteristic antibody-binding rate). If diffusion-limited antibody transport is achieved, the antibody removal rate may be raised further by increasing the number and length of the SAF fibers and by increasing the blood flow rate through the SAF.

show abstract

Principles and Biophysics of Dialysis

Cited by 58 publications

References 33 publications

Breath Ammonia Analysis: Clinical Application and Measurement

Breath Ammonia Analysis: Clinical Application and Measurement

Computational fluid and mass transport on macro and micro scales in an artificial kidney

Mathematical and Experimental Analyses of Antibody Transport in Hollow‐Fiber‐Based Specific Antibody Filters

Contact Info

Product

Resources

About