Backfiltration in Hemodialysis with Highly Permeable Membranes

Stiller, S.; Mann, H.; Brunner, H

doi:10.1159/000410764

Cited by 67 publications

(27 citation statements)

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“…The risk of backfiltration of bacteria or endotoxins due to pressure gradient is par ticularly high with high-flux membranes [1,2]. Endotoxin or endotoxin-like substances are able to stimulate the production of inter leukin 1 [3,4,6,7], serotonin, and histamine and to activate the complement system [16], inducing clinical manifestations such as fe ver, hypotension, and shock.…”

Section: Discussionmentioning

confidence: 99%

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High-Permeable Membranes and Hypersensitivity-Like Reactions: Role of Dialysis Fluid Contamination

Bigazzi

Atti²,

Baldari

1990

Blood Purif

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We have recently observed repeated hypersensitivity-like reactions (skin flush, face and tongue tingling, hypotension, and dispnea) during the first 5 min of dialysis in a small number of our dialysis population treated with high-flux membranes and traditional acetate dialysate. This prompted us to investigate the relationship between these reactions and the presence of contamination of the dialysate fluid. We hypothesized that in the presence of contaminated dialysate fluid and high-flux membranes backfiltratin of pyrogens may occur through the membrane into the blood compartment, leading to hypersensitivity-like reactions. These events are more likely to occur at the onset of dialysis due to rapid changes of hydrostatic pressure gradients across the dialysis membranes. 6 out of 48 dialysis patients who experienced hypersensitivity-like reactions were followed for 4 weeks. During the 1st week they were treated with high-permeable membranes and during the 2nd week with cuprophane membranes. The dialysate showed high levels of contamination with bacteria and endotoxin during dialysis with both types of membranes (microbial count 4,123 ± 2,756 and 1,991 ± 1,950 colony-forming units/ml; endotoxin 26.2 ± 8.4 and 23 ± 4.2 endotoxin units/ml, respectively); however the symptoms occurred only during dialysis with high-flux membranes. This suggests that backfiltration of contaminated dialysate into the blood might have occurred during the early phases of dialysis only when using high-flux membranes, but not when using cuprophane membranes. To test this possibility we introduced a new dialyzer-rinsing device consisting of two simple connection lines which allow to rinse, in a concurrent manner, the dialysate and the blood compartments of the dialyzer with sterile saline solution. Subsequently, blood was allowed to perfuse the dialyzer, while sterile saline solution was still present in the dialysate compartment. Only when a blood flow rate of 300 ml/min was achieved, the dialysate compartment was filled with regular dialysate. All previously symptomatic patients were treated, during the last 2 weeks of the study, with this new

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Section: Discussionmentioning

confidence: 99%

“…A particular risk linked to the use of these membranes is the backfiltration of dialysate when changes of pressure gra dients occur within a dialyzer [1,2], This is potentially dangerous since the dialysate can be occasionally contaminated by endotoxins or bacteria.…”

Section: Introductionmentioning

confidence: 99%

High-Permeable Membranes and Hypersensitivity-Like Reactions: Role of Dialysis Fluid Contamination

Bigazzi

Atti²,

Baldari

1990

Blood Purif

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“…The introduction of ultra-short dialysis treatments with high blood flow and high flux dialyzers brought other unexpected, undesirable effects, namely back filtration or retrofiltration of dialysate to the blood compartment [79,80] . Ronco [81] explained that back filtration (retrofiltration) is particularly pronounced with long dialyzer and the high flows of blood and dialysate.…”

Section: High Blood Flow Rates and Retrofiltrationmentioning

confidence: 99%

Treatment Time and Ultrafiltration Rate Are More Important in Dialysis Prescription than Small Molecule Clearance

Twardowski

2006

Blood Purif

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Chronic hemodialysis sessions, as developed in Seattle in the 1960s, were long procedures with minimal intra- and interdialytic symptoms. Over the next three decades, dialysis duration was shorten to 4, 3, even 2 h in thrice weekly schedules. This method spread rapidly, particularly in the United States, after the National Cooperative Dialysis Study suggested that the time of dialysis is of minor importance as long as urea clearance multiplied by dialysis time and scaled to total body water (Kt/V_urea) equals 0.95–1.0. This number was later increased to 1.3, but the assumption that hemodialysis time is of minimal importance remained unchanged. However, Kt/V_urea measures only the removal of low molecular weight substances and does not consider the removal of larger molecules. Nor does it correlate with the other important function of hemodialysis, namely ultrafiltration. Rapid ultrafiltration is associated with cramps, nausea, vomiting, headache, fatigue, hypotensive episodes during dialysis, and hangover after dialysis; patients remain fluid overloaded with subsequent poor blood pressure control leading to left ventricular hypertrophy, diastolic dysfunction, and high cardiovascular mortality. Kt/V_urea should be abandoned as a measure of dialysis quality. The formula suggests that it is possible to decrease t as long as K is proportionately increased, but this is not true. Time of dialysis should be adjusted in such a way that patients would not suffer from symptoms related to rapid ultrafiltration, would not have other uremic symptoms and most patients would have blood pressure controlled without antihypertensive drugs.

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“…This phe nomenon has been well described by several authors [1][2][3]. The physical characteristics of dialysis membranes and the dialysis operating conditions which give rise to backfiltration have been examined in detail.…”

Section: Introductionmentioning

confidence: 85%

Critical Analysis of Formulas for Estimating Backfiltration in Hemodialysis

1992

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The advent of high-flux dialyzers introduced the phenomenon of backfiltration as a regular occurrence in hemodialysis. Methods for calculating an estimate of backfiltration are described in detail, including an examination of the response of backfiltration to changes in applied pressure. A simple expression for the prediction of backfiltration as a function of net ultrafiltration is presented. Methods for estimating backfiltration have been published previously, but were based on incorrect assumptions; the errors present in those papers are highlighted and discussed here.

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Backfiltration in Hemodialysis with Highly Permeable Membranes

Cited by 67 publications

References 0 publications

High-Permeable Membranes and Hypersensitivity-Like Reactions: Role of Dialysis Fluid Contamination

High-Permeable Membranes and Hypersensitivity-Like Reactions: Role of Dialysis Fluid Contamination

Treatment Time and Ultrafiltration Rate Are More Important in Dialysis Prescription than Small Molecule Clearance

Critical Analysis of Formulas for Estimating Backfiltration in Hemodialysis

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