Josephus Paulus Clemens Maria van Doornmalen Gomez Hoyos. Dutch Norm Committee and Dutch delegate in EN TC 102 WG 2 Testing EN TC WG 3 Requirements

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1 Steam penetration Josephus Paulus Clemens Maria van Doornmalen Gomez Hoyos March 2012 Dutch Norm Committee and Dutch delegate in EN TC 102 WG 2 Testing EN TC WG 3 Requirements EN TC WG 5 Small steam sterilizers EN TC WG 6 Gas sterilizers EN TC WG 7Biological and chemical indicators ISO TC 198 WG 1 Industrial ethylene oxide sterilization ISO TC 198 WG 3 Moist heat sterilization ISO TC 198 WG 4 Biological indicators ISO TC 198 WG 6 Chemical indicators ISO TC 198 WG 13 Washer-disinfectors

2 Outline Standards Strategy Steam penetration tests Chemical Indicator update Standards are necessary confidential

3 Medical Research Council (1959, MRC) Perkins MRC Time Temp Time Temp [min] [ C] [min] [ C] Rational MRC: Steam quality

4 Criteria in norms Pressure Temperature Phase I Phase 1: Conditioning Phase 2: Sterilization Time Phase 3: Drying and pressure equalization Specify conditions in sterilization phase Specify end result Specify NOT phase 1 and before

5 ISO Part 1: General requirements Clause 4 Classification 4.2 Class 1: process indicators 4.3 Class 2: indicators for use in specific tests 4.4 Class 3: single variable indicators 4.5 Class 4: multi-variable indicators 4.6 Class 5: integrating indicators 4.7 Class 6: emulating indicators

6 Chemical indicators norm ISO Part 1: General requirements Part 2: Test equipment and methods Part 3: Class 2 indicators for steam penetration test sheets Part 4: Class 2 indicators for steam penetration test packs Part 5: Class 2 indicators for air removal test sheets and packs Part 6: possibly Process Challenge Devices for steam sterilization (New work item ISO/TC 198/WG 6)

7 The original "Huckaback Towel Pack" according to Dr. J. H. Bowie and Mr. J. Dick THE BOWIE AND DICK AUTOCLAVE TAPE TEST, The Lancet, (1963), S.586 7

8 Steam sterilization process Steam injection Start of sterilization phase Steam sterilization conditio Pressur re Time Suction

9 Steam penetration and condensation Condensation front Gases sucked out, textile stays wet Good penetration Time

10 Insufficient deep vacuum Condense front will not disappear

11 Effect NCG s Steam Injection (Steam with NCG s) O 2, N 2, CO 2, H 2 O Steam injection, pressure increasing Condensation of water

12 Helix Examples Helix schematically Tube Receptacle Lumen

13 Penetration in lumen Pressure Time Length = L Length = ½L Closed end

14 Examples hollow instruments Lumen

15 Helix Examples Helix schematically Tube Receptacle Lumen

16 Configuration of instruments Relatively difficult to penetrate Relatively easy to penetrate

17 Swirl Swirl Well known and described phenomena Axial dispersion and flow phenomena in helically coiled tubular reactors for flow analysis and chromatography, R. Tijssen, Analytica Chimica Acta, 114, 1980, 71-89:

18 Wall thickness Wall thickness More heat capacity (e.g., more condensation) Heat transfer Research ongoing

19 Dimensions of tube Radius Length r Research ongoing

20 Norms Institutes International Organization for Standardization (ISO) ISO standards CEN EN standards Country Norm Institute Germa ny (DIN) UK (BSI) The Netherlands (NEN) France (Afnor) USA (AAMI) South Africa (SABS) Colombia (ICONTE C) Brazil (ABNT ) Japan (JISC ) China (SAC ) Australia (SA)

21 Sequence of standards A higher organization supersedes regional or country standards If a topic is address on a higher level the lower level must stop work(ing) on the that topic ISO standard DIN ISO European standard Country standard DIN EN DIN 12345

22 Current situation in norm committees penetration tests Current standard EN 867 part 5: Non-biological systems for use in sterilizers - Part 5: Specification for indicator systems and process challenge devices for use in performance testing for small sterilizers Type B and Type S 4.2 Process challenge device for porous load 4.3 Indicator systems for use in the porous load process challenge device 4.4 Alternative indicators equivalent to the porous load process challenge device test 4.5 Process challenge devices for hollow instrument loads (hollow load process challenge device) Parts 1 to 4 are already in the ISO part 1 to 4

23 EN Small steam sterilizers Draft version: Device will go in informative annex possibly disappearal

24 EN 285 Sterilization Steam sterilizers Large sterilizers (includes Amendment A2:2009) Hollow load test When the sterilizer is tested in accordance with Clause 15, the indicator system shall have reached its endpoint as described by the manufacturer of the indicator system Indicator system in accordance with EN for the hollow load test.

25 EN 285 penetration test 8.1 Steam penetration When tested in accordance with 16.1, the result shall be in accordance with When tested in accordance with 16.2, the result shall be in accordance with When tested in accordance with Clause 17, the result shall be in accordance with When tested in accordance with Clause 15, the result shall be in accordance with

26 EN 285 penetration test Bowie and Dick test When tested in accordance with Clause 17, the result shall be in accordance with NOTE 2: In healthcare there has been an increase in the use of instruments with long lumens. For some of these instruments the air removal efficacy identified by the tests based on textile loads may be inadequate. These tests have their origin in the steam penetration test using a textile pack1). It was designed to establish that at the commencement of the plateau period, air removal had been sufficient to The hollow load test complements these tests and should be achieve a vapour temperature throughout a textile load equivalent to the regarded as an addition to, and not as a replacement to them. vapour pressure of the steam in the sterilizer chamber. The hollow load test complements these tests and should be regarded as an addition to, and not as a replacement to them. A successful hollow load test indicates adequate air removal and even steam penetration into a process challenge device. A failure of any steam penetration test can be caused by an inefficient air removal stage, the presence of an air leak into the sterilizer chamber, and/or the presence of non-condensable gases in the steam supply."

27 Chemical indicators norm ISO Part 1: General requirements Part 2: Test equipment and methods Part 3: Class 2 indicators for steam penetration test sheets Part 4: Class 2 indicators for steam penetration test packs Part 5: Class 2 indicators for air removal test sheets and packs Part 6: possibly Process Challenge Devices for steam sterilization (New work item ISO/TC 198/WG 6)

28 Current situation Doubts in: EN TC WG 5 revision EN Put the devices in informative annex Will make remark that the device does not represent actual loads ISO TC 198 WG 6 EN 867 part 5 revision Started Round Robin testing in labs involved, standardized protocol, device, indicator, conditioning, sterilizers, processes No consistency found in results Next meeting May 2011 Scientific approach no relation with actual loads

29 Orientation study Orientation study to find out if commercial available Process Challenge Device fulfil the claims made and the ISO part 3 or 4. Method used is: compare available test in with equipment fulfilling the norms According to specified test processes in the ISO part 4 This is not a detailed study

30 Claims used Penetration test material ETS (3M, Germany) Claim: comply with the ISO part 4 (full claim see last slides) GKE Compact PCD Bowie-Dick Simulation Test Claim: Air removal and steam penetration test validated according the test method of EN ISO part Class 2 with reference to the 7 kg test pack in EN 285 and hollow test exceeding the requirements of EN Interster ISP control Helix Test system Claim: EN EN-ISO (class 6 indicators)

31 Test equipment and conditions Test sterilizer: Lautenschläger type STE Programs used are programmed as described in the ISO :2007(E)Sterilization of health care products Chemical indicators Part 4: Class 2 indicators as an alternative to the Bowie and Dick-type test for detection of steam penetration Plateau period 3,5 minutes in all processes Before testing sterilize was warmed up before testing

32 B.1 Cycle 1: Air removal by sub-atmospheric pulsing

33 B.2 Cycle 2: Air removal by trans-atmospheric pulsing

34 B.3 Cycle 3: Air removal by super-atmospheric pulsing

35 Positions of PCDs during testing

36 Experimental method Processes used out of the ISO part 4 : B.1 Cycle 1: Air removal by sub-atmospheric pulsing B.2 Cycle 2: Air removal by trans-atmospheric pulsing B.3 Cycle 3: Air removal by super-atmospheric pulsing Cycles: Pass See back up slides for details on standard processes Bad vacuum Air injection ETSses are used to verify cycles

37 Interster ISP control Helix Test system Used in experiment: Art.No steam Dark 134 C 3,5 min / 121 C 15 min

38 Results Interster ISP control Helix Test system Remarks: Colour changes of indicators are seen after process, but look similar for pass and fail None of the processed indicators reaches reference colour (Added) value of product not understood (not for small or large sterilizers)

39 Results GKE Compact PCD Bowie-Dick Simulation Test

40 Remarks: Results GKE Compact PCD Bowie-Dick Simulation Test Fail B3 cycle with air injection resulted in a pass This introduces a false sense of safety. (Air Leakage test only detects sub atmospheric leaks. Control valves are controlled by compressed (typically 6 bar). Leaks in the valves are shown with air injection tests) Fail B1 cycle with air injection restated in a pass (tested up to 3 bars) May introduce a false sense of safety (see above). It looks like the PCD Bowie and Dick test (ref ENS) do not comply with 2 out 3 tests to comply with the ISO part 4

41 ICEN/CENELEC internal regulations define a standard Nature is NOT democratic and Document, established by consensus and approved by a recognized does body NOT that provides, do for consensus common an repeated use, rules guidelines Human can or define characteristics a meter for but activities or their results, human aimed cannot at the decide achievement when organisms of the optimum die degree of order in a given order. We need evidence confidential

42 Basis Standards are necessary. Standards should be evidence based Standards are not always evidenced based Not data available Not possible Other reasons, confidential

43 olutions and products Ethical Safe Evidence based where possible Prefer evidence based standards Perform studies to bring evidence to the public domain End users Standard committees confidential

44 We do not believe in the saying: Better do something than nothing if it introduces doubts if safety could be jeopardized we do not want to introduce a false sense of safety confidential

45 Members National committees and workgroups End users, manufacturers, governmental institutions, research centers European committees Delegates from European countries ISO committees Delgates from member countries Composition of committees should be a reflection form users confidential

46 Steam penetration Hollow A Hollow A, hollow load A, helix, PCDs Type in Google images: helix devices steam penetration confidential

47 ISO part 6 ISO part 6 is intended to replace EN 867- Clause defines the hollow load 4.5 Process challenge devices for hollow instrument loads (hollow load process challenge device) With Hollow load, hollow A and helix is meant the same: confidential

48 Discussion Since introduction helix systems a discussion First half 2009:TC 198 WG 4 Chemical indicators perform a Round Robin test 3 revisions of protocol: no data in public domain Neuss lab performed their own study confidential

49 Some helix testing in Neuss lab Helix PCD device as in Round Robin Study Protocol as in Round Robin Study Process as I in Round Robin Study Chemical indicators as in Round Robin Study Our 2 test sterilizers (11 l and 342 l) confidential

50 Process Pressure CP Come-up 4 pulses : CP vac = 300, 320, 350, 370, 400 mbar 3 pulses : CP steam = 950mbar Come-up : CP = 3100 mbar Target P/ t: 400mbar/min CP Steam CP vac Time confidential

51 Results I Chemical Indicator Colour Development B1 400mbar/min - ST3-RM 11 litre mbar mbar mbar mbar % 50% 100% 0% 50% 100% 0% 50% 100% 0% 50% 100% confidential

52 Results II Chemical Indicator Colour Development B1 400mbar/min ST litre mbar mbar mbar mbar % 50% 100% 0% 50% 100% 0% 50% 100% 0% 50% 100% confidential

53 Results interpretation I confidential

54 Results interpretation II Differences between small and large test sterilizer Round Robin does not classfy the PCD (yet?) Original Standard Textile pack in process (VCP = 300 mbar) ISO , max 2 K In process with VCP = 300 mbar: 75,4, 81.4 and 88.7 K confidential

55 Conclusion Hollow, hollow A and/or helix PCDs introduce a false sense of safety should not be used in standards should not be used for steam penetration should not be used Batch Monitoring systems standard committees should look at these results E.g. proposal for Medical Device Simulator (NWI: DIN 58921) (publication in preparation) confidential

56 Alternatives for penetration tests and BMS Test meeting requirements in ISO part 4 Large sterilizers ETS Small sterilizers 1300 and 1301 (and soon 1233) BMS No standards, research ongoing confidential

57 ISO part 1, class 4, 5 and 6 CIs Discussions on class 5 and 6 in committees and field Decided to study 6 commercially available class 6 CI for steam sterilization confidential

58 Protocol based on ISO part 1 Square wave 134 C Vary the exposure time: 0, 1, 15, 30, 45, 60,..., 300, 330, 360, 390, 420, and, 900 s X-rite 528 Spectrodensitometer to measure color Measured CI and reference ink on indicator Indicator surface Reference color surface Tested against there own Stated Values and accuracies confidential

59 Criteria class 6 CIs 3M All Rights Resered. confidential

60 Some results: example color changes CI 330, 360, 390, 420, and, 900 s 0, 1,15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165, 180 s 195, 210, 225, 240, 255, 270, 285, 300 s Obviously human eye not objective Therefore measurements confidential

61 Some more results Difficult if possible at all to see the results What is a pass? When is it a pass? confidential

62 Method measuring objective L*a*b method Ink measured Reference color measured Result ink result reference. Pass results equals 0 Fail result does not equal 0 confidential

63 Measured results Non of the results go to 0 Almost all turn over too early In some case Cis color difference is hardly seeable If not seeable with measurements not seeable with human eye confidential

64 Conclusions Standards are necessary Current helix device does not meet claims Current color change based (class 6) Cis do not meet claims Do not use helix shaped devices Suggestion translate the published articles on helix shaped devices in local language Become member of (national) norm committees confidential