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Dialysis Fluid Purity Best Practice Guidelines (and real life) Elizabeth Lindley St James’s University Hospital and Leeds General Infirmary Leeds, UK.

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Presentation on theme: "Dialysis Fluid Purity Best Practice Guidelines (and real life) Elizabeth Lindley St James’s University Hospital and Leeds General Infirmary Leeds, UK."— Presentation transcript:

1 Dialysis Fluid Purity Best Practice Guidelines (and real life) Elizabeth Lindley St James’s University Hospital and Leeds General Infirmary Leeds, UK

2 European and National Guidelines ERA-EDTA o European Best Practice Guidelines for Haemodialysis Part 1 Section 4: Dialysis Fluid Purity Nephrol Dial Transplant (2002) 17 Suppl 7: EDTNA/ERCA o Technical Guidelines for the Control and monitoring of microbiological contamination in water for dialysis EDTNA/ERCA Journal 2002; 28(3), UK Renal Association o Guidelines 3rd Edition Chapter 3: Haemodialysis (Draft, March 2002) DGN Guidelines (draft edition)

3 ‘ERA’ guidelines Drafted by Prof Bernard Canaud with input from the panel of experts in haemodialysis o The panel also covered when to refer patients and start dialysis, adequacy, biocompatibility, anti- coagulation, infection control and vascular disease. Evidence-based where possible, otherwise expert opinion o Fresenius helped with extensive literature search Circulated to the National Associations for comment and approval

4 ‘EDTNA’ guidelines  The EDTNA guidelines were developed after a survey of renal units in 14 countries showed the majority of units aimed to meet the EP limits for bacteria and endotoxin contamination BUT…… o 40% had no policy for routine disinfection of the water distribution pipework o Only 50% were regularly testing the dialysis water for endotoxin o Most units were checking bacteria levels routinely, but often with unsuitable culturing conditions EDTNA technical members requested guidelines

5 ‘EDTNA’ guidelines Drafted by a Project Group with help from Rolf Nystrand (Consultant Microbiologist) o Input from an panel of interested people from renal units, industry and the regulatory bodies, and from contributors to the Journal Club Evidence-based where possible, otherwise expert opinion or good practice Approved by the European Society for Artificial Organs and ERA-EDTA

6 National guidelines UK Renal Association Guidelines were drafted by two doctors and a scientist and posted on the internet for feedback DGN guidelines were drafted by a group of nephrologists with input from chemists, microbiologists, technicians and expertise from the water supplier  This sounds like a good multidisciplinary approach

7 In-house quality assurance policies ERA guidelines EDTNA guidelines National guidelines Local knowledge and COMMON SENSE!

8 Do the guidelines agree with each other? What do they recommend?

9 Chemical quality - chlorine Maximum allowed level:  ERA “Meet European Pharmacopoeia”

10 50 Ammonium not included in list. EP includes test for heavy metals

11 Chemical quality - chlorine Maximum allowed level:  ERA Meet EP (Total chlorine < 0.1 ppm)  EDTNA Total chlorine < 0.1 ppm*  DGN Total chlorine < 0.1 ppm Frequency of testing:  ERA Daily  EDTNA Daily* (longer intervals if justified)  DGN According to local circumstances * Guidelines on carbon adsorption, to be published soon

12 Other daily tests ERA Guideline IV.3.1 recommends daily checks of Ca and Mg (Hardness) & Na (conductivity)

13 Leeds local policy on ‘daily’ checks Conductivity is monitored continuously  Alarms should be checked regularly Chlorine and hardness would only be checked daily in exceptional circumstances  Weekly monitoring for hardness (when brine tanks are filled) has been perfectly adequate  Weekly (where carbon filters are installed) or monthly monitoring for chlorine is justified o We have a history of relatively low chlorine levels (0.05 to 0.30 ppm) and a close relationship with our water supplier

14 Other chemical contaminants Contaminants that should be checked:  ERA As minimum, specified in EP  EDTNA Will probably recommend EP plus any ‘local problems’  DGN 12 point list

15 EP = 2000

16

17 The Nitrate Problem Limit for tap water 50 ppm Typical rejection by RO = 85 to 95%  Will reduce high nitrate tap water to about 5 ppm  To achieve 0.05 ppm would require a triple RO EP requires 2 ppm as NO 3 AAMI requires 2 ppm as N (  9 ppm as NO 3 )  US experts say this has not led to any problems Is the EP evidence based……

18 Highly purified water (Question from Roelf Smit) Is highly purified water with conductivity below 1.1 µS/cm really required for HDF? (My opinion, not EDTNA) Meeting this strict requirement on conductivity would be very expensive and it seems to be unnecessary.  Conductivity is mainly due to Na (especially if water has been softened  About 137 mmol/l of Na will be added to the water

19 I would invest in keeping the distribution system free from bacteria (which are absolutely forbidden in HDF substitution fluid), rather than water that is free from sodium

20 Testing for chemical contaminants Frequency of testing (after validation):  ERA Six-monthly (quarterly in Appendix) Monthly tests for aluminium  EDTNA Will probably recommend 6 to 12 monthly More frequent for Al? Local decision

21 Data from the RUDIAL Test Service provided by ALcontrol Labs for about 54 Euros per location. (The labs send us the 5 sample bottles required for each location every 6 months)

22 Sampling water for microbiological tests Frequency of testing:  ERA At least monthly (after validation)  EDTNA At least monthly (after validation) Where to sample:  ERA Incoming (tap) water Entrance to dialysis machines  EDTNA At points in treated water loop with highest bacterial load

23 Testing substitution fluid could be a problem. “Sterile” = <1 cfu/1000 litres A good, practical test procedure is required (e.g. Using an in-line filter during a normal HDF session)

24 Sampling water for microbiological tests Sample ports:  ERA Flame sterilised taps  EDTNA Specialised ports, flame sterilised or alcohol disinfected taps Sample storage:  ERA Time not specified, 3 to 6°C  EDTNA Up to 6 hrs at <10°C (not frozen) Longer if in validated conditions All guidelines prefer immediate testing

25 Bacteria levels in water Maximum level (for conventional dialysis):  ERA <100 cfu/ml (but aim for ultrapure)  EDTNA <100 cfu/ml (but aim for ultrapure)  DGN also <100 cfu/ml Test methods:  ERA TGEA or R2A, 20 to 22°C, 7 days  EDTNA TGEA or R2A, 20 to 22°C, 7 days  DGN TGEA or R2A, 17 to 23°C, 5-7 days

26 Endotoxin levels in water Maximum level (for conventional dialysis):  ERA <0.25 IU/ml (but aim for ultrapure)  EDTNA <0.25 IU/ml (but aim for ultrapure)  DGN also <0.25 IU/ml <0.03 IU/ml for on-line HDF Test methods:  ERA LAL assay  EDTNA LAL assay or other validated technique

27 Aside - why I like to check endotoxin  Bacteria in the distribution system, will be producing waste products that that can pass through a dialyser membrane (e.g. pyocyanin - see caption).  We don’t test for waste products, only for actively reproducing bacteria and endotoxin.  Something could happen to stop the bacteria reproducing (e.g. UV irradiation) but for gram-negative bacterial endotoxin will still be there Pyocyanin produced by P. aeruginosa in a dialysis fluid sample. This pigment makes pus in infected wounds go blue or green.

28 Maintenance Changes of resins, carbon and filter  ERA Periodic according to manufacturer’s recommendations and microbiology  EDTNA (Carbon) according to manufacturer’s recommendations and microbiology Disinfection of RO(s) and distribution system:  ERA At least once a month  EDTNA At intervals based on microbiology, default = at least once a month

29 But water is not the final product…. What do the guidelines say about dialysis fluid?  ERA: o Use same sampling, storage & testing procedures as water o Meet EP guidelines (ambiguous for standard dialysis) o Perform ‘micro-biological’ check-up of all machines monthly  EDTNA: o Take samples from in-line ports or the dialyser outlet o Use the same culturing technique (and limits) as for water o Modify disinfection protocols if endotoxin levels > water o Check a representative sample of machines each month  DGN: o Use same limits for dialysis fluid as for purified water

30 Testing dialysis fluid in real life For my centre, to meet the ERA requirement would mean sampling and testing over 160 machines each month  This would cost over Euros per year  What would the benefit be? Our current policy is to test a sample of machines in each location so that every machine is tested on a 6 monthly or annual basis

31 Minimising the cost of tests (1) Bacteria  Accredited tests in labs are costly - negotiate a ‘low resolution’ or ‘indicative’ test with simplified counting o Actual count up to 50 o Nearest 10 from 50 to 200 o >200 o >2000  Develop an in-house test procedure

32 In-house bacteria tests

33 Incubate in a secure cupboard. I have an old laboratory incubator - the temperature controller doesn’t work but it’s okay for culturing at room temperature

34 In-house testing - bacteria Problems  A good relationship with microbiology is essential  Health and safety assessment required Advantages  Cheap (~60 cents per sample)  Quick (no booking or sample forms)  Plates can be checked easily  No chasing up of results  You can incubate for 14 days (for moulds)  You get to see the colonies

35 Moulds on a plate incubated for 14 days

36 The value of dilution

37 Minimising the cost of tests (1) Endotoxin  External labs are expensive - negotiate a special price for many samples with only one or two positive controls  In-house gel-clot tests are time consuming and costly when multiple dilutions are required - form a local group and lease an automated analyser

38 Kinetic LAL test kit leased jointly by the renal units in West Yorkshire. I do routine tests on the first and third Tuesday of each month. This works out at about 11 Euros per sample

39 You need to be able to make the calibration standards and to pipette out small volumes accurately

40 Kinetic analyser Problems  Space required for kit  Training required for staff Advantages  Compared to in-house gel-clot tests o Cheaper and quicker for large number of tests o No water bath, no careful timing  Compared to external lab o Cheaper for large number of tests o No chasing up of results o Unexpected results can be checked immediately

41 Conclusions The Best Practice Guidelines are in reasonable agreement  Especially for microbiological testing Local practice must depend on local conditions Invest in high quality equipment not a more expensive monitoring programme!  EDTNA guidelines include advice on system design


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