Fouling of Ultrafiltration and Hemodialysis Membranes by Plasma Proteins

Leypoldt, John K.

doi:10.1159/000170177

Cited by 16 publications

(7 citation statements)

References 7 publications

(11 reference statements)

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“…Our findings indicate that dialysis efficiency is not reduced significantly over treatment times ranging from 120 to 300 min, with blood flow rates of 350-500 mL/ min. This finding differs from the perceived loss of dialyzer efficiency because of microthrombosis already reported in CRRT, [10][11][12][13] and may be a result of the shorter period during which our membranes were exposed to unheparinized blood. Our blood flow rates were more rapid than normal for CRRT, which may have contributed to our perceived lack of hemodialyzer thrombosis.…”

Section: Discussioncontrasting

confidence: 95%

“…The HF technique has been described previously as a risk factor for inadequate delivery of HD, 9 and membrane clearances in continuous renal replacement therapy (CRRT) have been shown to deteriorate rapidly when the HF technique is used. [10][11][12][13] Prior studies of used HF-HD membranes do not show decreased in vitro membrane clearances, 3 but lack of anticoagulation was a risk factor for inadequate delivery of dialysis in another study. 9 Concern has been expressed recently regarding insufficient delivery of dialysis in intensive care unit (ICU) patients.…”

Section: Introductionmentioning

confidence: 99%

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Clinical consequences of heparin‐free hemodialysis

McGill

Blas

Bialkin

et al. 2005

Hemodialysis International

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Heparin-free hemodialysis (HF-HD) has been increasingly used in patients at risk for bleeding, especially in the intensive care unit (ICU). Lack of heparin can reduce solute clearances in continuous hemofiltration; the effect on HD is undefined. Failure to recognize an effect of the anticoagulation strategy upon delivered clearance could contribute to the known problem of underdialysis in the ICU. In addition, the consequences of "locking" dialysis catheters with concentrated heparin solutions are also unclear. This study was designed to define the clinically relevant consequences of HF-HD and catheter locking. In part I, we performed 200 HD treatments on inpatients, of which 100 were performed with heparin, and 100 were performed as HF-HD. We calculated prescribed and delivered Kt/V and dialysis efficiency. In part II, a separate group of 14 patients undergoing HF-HD via central venous catheters had measurement of activated partial thromboplastin time (aPTT) during the last hour of dialysis, as well as 15, 60, and 240 min after catheters were locked with 1:5000 heparin. The prescribed Kt/V was 1.74+/-0.31 for standard HD with heparin vs. 1.66+/-0.36 for HF-HD (p=ns). The delivered Kt/V was 1.42+/-0.32 vs. 1.36+/-0.38 (p=ns). Efficiency was 0.82 vs. 0.84 (p=ns). Baseline aPTT was 28+/-5 s, and increased to 126+/-54 s, 15 min after locking (p<0.0001) and to 71+/-50 s, 60 min after locking (p=0.005). By 240 min, the mean aPTT had fallen to 33+/-9 s (p=0.03), although individual values were still as high as 50 s. The HF technique does not compromise delivery of dialysis to inpatients. Increased treatment time is not necessary. Locking catheters with heparin after HF-HD resulted in prolonged unintentional anticoagulation.

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Section: Discussioncontrasting

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Clinical consequences of heparin‐free hemodialysis

McGill

Blas

Bialkin

et al. 2005

Hemodialysis International

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“…Only slight variations in K uf were observed during the sessions, demonstrating a constant performance of the hydraulic permeability of the membrane and suggesting the possible usage of these series (EE) in soft hemodiafiltration. The utilization of this membrane in soft hemodiafiltration achieved its best performance during the first 2 h (UF rate of 75 ml/min), while the relative loss of ultrafiltration, observed during the second part of the session, can probably be attributed to the fouling of the membrane, due to a thin protein layer formed on the surface (32). As β2M clearance is closely correlated to ultrafiltration, a reduction of the solute clearance is likely to occur after the third hour of treatment.…”

Section: Discussionmentioning

confidence: 99%

Vitamin E‐coated Membrane Dialyzer and β2‐microglobulin Removal

2003

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This study was designed to test the removal of beta2-microglobulin (beta2M) in a vitamin E-modified membrane. We investigated in vivo the dialyzer (Excebrane, series EE, 1.8 m2) with respect to hydraulic permeability (Kuf), maximum ultrafiltration rate (UF max), sieving coefficient (Sc), and solute clearances in hemodialysis (HD) and in soft hemodiafiltration (HDF). Kuf was 18.4 ml/h/mmHg, UF max was 75 ml/min, and Sc for beta2M was 0.45. Clearance values at 400 ml/min of Qb in HD were 258 ml/min for urea, 201 ml/min for creatinine, and 135 ml/min for phosphate. In soft HDF, clearances were slightly higher. beta2M clearance was 26 ml/min in HD and 43 ml/min in soft HDF. In conclusion, Excebrane (series EE) procures a soft HDF with an amount of substitution fluid in post dilution mode of over 60 ml/min. Remarkable small solute clearances were obtained when the blood flow was raised to 400 ml/min. A significant reduction of beta2M is demonstrated by HDF.

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“…Unfortunately, transport properties determined using these simple solutions may be substantially different from those determined using blood because of membrane fouling by plasma proteins, unequal distribution of solutes between plasma water and within blood cells, and binding of solutes to plasma proteins. For example, the fouling of dialysis membranes by plasma proteins can decrease their ultrafiltration coefficients and sieving coefficient for P,-microglobulins ( P2m) (7); the concentration of urea inside peripheral erythrocytes in uremic subjects is only 80% that of plasma (8); and aluminum is largely protein bound and is cleared poorly by hemodialysis without first chelation by desferroxamine (9). These caveats should be kept in mind while interpreting in vitro clearance data or com-paring performance among various dialyzers tested under different conditions.…”

Section: Transport Propertiesmentioning

confidence: 99%