Hong Kong Sterile Services Management Association Limited. Seminar. 25 th June 2014

Transcription

1 Hong Kong Sterile Services Management Association Limited Seminar 25 th June Bowie-Dick-Test: Use of Compact-PCD vs. Bowie-Dick-Test Pack 2. How to Monitor and Evaluate Steam Sterilization Processes 3. Cleaning Indicators 4. Instant-SCBI vs. Rapid Indicators Dr. Ulrich Kaiser, gke GmbH, Germany U. Kaiser 06/2014

2 Definition Sterile : Complete inactivation of viable germs on a product The number of alive germs can be reduced continuously with increasing sterilization time but SAL cannot reach zero. (Theory of kill kinetics) According EN in the EU a product can be labeled sterile, if the sterility assurance level (SAL) is EN accepts SAL 10-3 when sterile liquid filling is done. In the USA the required SAL is depending on the application risk (SAL ) U. Kaiser 01/2011 Thermal Sterilization Dry Heat Sterilizer Cooled down Air (<180 C) Hot Air (180 C) Blower Cooled air falls down Hot Air releases energy (decreasing temperature) Product to be sterilized (e.g. surgical Instrument) (increasing temperature) Heated air goes up Heater J. Metzing 12/2006

3 Principles of the gravity displacement sterilization cycle (1) Steam Air U. Kaiser 07/2005 Principles of the gravity displacement sterilization cycle (2) Container with filter on top Steam Steam Air Light permeable textile packaging Container with filter on top and at the bottom Tight packaging U. Kaiser 07/2010

4 Sub-atmospheric Fractionated Vacuum Sterilization Process warming-uptime Overpressure [bar] pressure [bar] temperature [ C] 3 4 temperature 134 pressure 2 3 BDS-Test 3,5 min fractionated vacuum time [min] 0 air-removal sterilization cooling drying U. Kaiser 07/2005 Super-atmospheric Fractionated Vacuum Sterilization Process warmingup-time Overpressure [bar] pressure [bar] temperature [ C] 3 4 temperature 134 pressure 2 3 BDS-Test 3,5 min fractionated time [min] 0 air-removal sterilization cooling drying U. Kaiser 07/2011

5 Trans-atmospheric Fractionated Vacuum Sterilization Process warming-uptime Overpressure pressure [bar] [bar] 3 temperature [ C] During sterilization (plateau phase) all surfaces are wet and in the packages physical nearly no steam or heat transport, no 4 temperature pressure change, kondensation 134 or vaporization takes place. pressure 2 3 BDS-Test 3,5 min time [min] 0 air-removal sterilization cooling drying U. Kaiser 11/2005 The air removal performance of a sterilization processes is the better: the deeper the lower pressure changing point is the higher the pressure difference between the upper and lower pressure changing point is Pressure the more air removal cycles the process has Time [min] Air removal time Warmingup time Sterilization time D. Kaiser 09/2008

6 No. + successful sterilization process unsuccessful sterilization process Sterilization Process Gravity-Cycle (Gravity- Displacement) Single Vacuum Cycle 100 mbar Vacuum-Injection- Cycle Super-Atmospheric Pressure Cycle (Over Pressure Cycle) Vacuum-Over-Pressure- Cycle Tabletop sterilizer class according EN Process- Characteristic Displacement Airremoval N poor S + (+) - - Steam S S S No. Goods to be sterilized Packing Instruments without holes Instruments without holes Porous goods (Cotton etc.) Hollow instruments like MIS*-instruments, endoscopes, catheters etc. without with with or without with or without Difficulty of Air- Removal easy difficult Sterilization Process Quality Dependence from the Steam Sterilization Process and the Goods sterilized 6 Vacuum-Over-Pressure- Cycle (stairs) S Sub- or trans- atmospheric Pressure Cycle (Fractionated Vacuum) B good *MIS = Minimal-Invasive-Surgical U. Kaiser 10/2013 Which are the critical sterilization variables in steam sterilization processes? (1)? 1 - Steam 2 - Condensation of Steam to Water 3 - Pressure 4 - Temperature-Time-Window U. Kaiser 11/2013

7 Dry Cellulose Packs (Cotton or Paper) create superheated non-condensing steam by hydroscopic condensation 140 C Biological indicator T= 6 C 134 C Biological indicators are not inactivated under superheated steam conditions U. Kaiser 03/2007 Which are the critical sterilization variables in steam sterilization processes? (2) 1 - Steam? Steam is water in the gaseous phase. Germs and biological indicators are not killed at the same speed in steam superheated steam using the same temperature-time-window (i.e. 121 C - 15 min; 134 C - 3 min) in comparison to the speed in steam sterilization processes. The kill velocity in non-condensed steam is similar to dry heat or in anhydrous liquids and requires similar temperature-time-windows (i.e. 160 C - 2 h; 180 C h). - NO U. Kaiser 11/2013

8 Steam Sterilization of infusion solution condensing steam at the outside glass walls 2 - Condensation of Steam to Water? (no condensation inside the bottle) Alternatively microwaves, infrared radiation, heating plates can be used to heat up the water steam steam biological indicator U. Kaiser 08/2009 Which are the critical sterilization variables in steam sterilization processes? (3) 2 - Condensation of Steam to Water? Condensing steam creates an excellent heat transfer to all areas where steam can condense to water. However, liquid sterilization in water demonstrates that the kill velocity of germs is identical in water without any condensation under the same temperature-time-window like in steam sterilization processes. During the plateau period in steam sterilization processes there is no condensation, however the same kill velocity occurs like in water. - NO U. Kaiser 11/2013

9 Which are the critical sterilization variables in steam sterilization processes? (4) 3 - Pressure? Pressure in the scale region of 1 10 bar or kpa does not influence the kill velocity of germs in any sterilization process. Pressure in steam sterilization processes is required to achieve the necessary temperature. The boiling point of water depends on the pressure (see table below). Pressure [bar] Temperature [ C] NO U. Kaiser 11/2013 Which are the critical sterilization variables in steam sterilization processes? (5) 4 - Temperature-Time-Window? If the temperature-time-window used in steam sterilization processes (121 C - 15 min; 134 C - 3 min) is also used in dry heat or anhydrous liquids, the kill velocity of germs or biological indicators is much lower than in steam sterilization processes under the same temperature-time-window. - NO U. Kaiser 11/2013

10 Temperature and time parameters to achieve overkill for the steam sterilization process according to EN ISO Temperature-Time-Window? Temperature [ C] Sterilization time [min]* Equilibration time [min]** F C [min] Remarks <0,5 15 Those conditions are only valid in presence of water <0,5 ca. 60 (wet surfaces). Temperature [ C] Dry heat and superheated steam sterilization process (incl. non-polar solvents and oils) Sterilization time [min]* Equilibration time [min] Remarks The temperature-come-up-time changes depending on the heat capacity of the goods and the insulation of the pack. * Sterilization time after reaching the temperature of the goods on the surface and in hollows ** If complete air removal is achieved U. Kaiser 05/2011 Which are the critical sterilization variables in steam sterilization processes? (6) The sterilization agent in steam sterilization processes is: - Water, having a defined temperature-time-window applied to all surfaces of the instruments (e.g. 121 C 15 min; 134 C 3 min = F 0 -value) - All surfaces must be wet to become sterile This information is written in the indicator standard EN ISO in U. Kaiser 11/2013

11 Which are the critical sterilization variables in the different sterilization processes? The following variables are defined as being critical in the standard EN ISO : Steam Dry heat Ethylene oxide (EO) Steam + Formaldehyde (LTSF) Vaporized hydrogen peroxide (H 2 O 2 ) Time, temperature and water (as delivered by saturated steam) Time and temperature Time, temperature, relative humidity and EO concentration Time, temperature, condensate (as delivered by saturated steam) and FO concentration Time, temperature, H 2 O 2 concentration and, if applicable, plasma (plasma does not sterilize, also H 2 O-vapour reduces the sterilization speed) U. Kaiser 11/2013 Reasons for superheated steam Superheated steam does not contain any condensate in the gas phase and is present in a steam sterilizer under the following conditions: 1. Pressure reduction in the steam pipe without sufficient cooling before entering the sterilizer 2. Sterilizer walls heated up to a higher temperature than the saturated steam temperature inside the sterilizer 3. Hygroscopic condensation inside non-conditioned cellulose materials (like cotton balls, packaging material, cotton and linen) Steam in the gasphase does not sterilize at a temperature up to 134 C, only water can sterilize under those temperature and time conditions U. Kaiser 09/2012

12 Steam consumption and contraction during condensation Steam about l/10 kg load 1000 ml steam approx. 1 ml condensate (water) Significant volume contraction of steam due to condensation condensate The heat transfer occurs directly at the condensation location on the instruments During condensation the steam volume diminishes (converted to water), consequently additional steam is forced into the generated vacuum U. Kaiser 01/2011 Volume contraction of water during Condensation Non-condensable gases (NCG) do not reduce their volume Steam 134 C Steam + NCG 134 C water NCG J. Metzing 01/2011

13 J. Metzing 06/2007 gke Steri-Record Bowie-Dick Test Sheet for Steam-Sterilization according EN ISO U. Kaiser 01/2011

14 U. Kaiser 07/2005 Temperature and time parameters to achieve overkill for the steam sterilization process according to EN ISO Temperature [ C] Sterilization time [min]* Equilibration time [min]** F C [min] Remarks <0,5 15 Those conditions are only valid in presence of water <0,5 ca. 60 (wet surfaces). Dry heat and superheated steam sterilization process (incl. non-polar solvents and oils) Temperature [ C] Sterilization time [min]* Equilibration time [min] Remarks The temperature-come-up-time changes depending on the heat capacity of the goods and the insulation of the pack. * Sterilization time after reaching the temperature of the goods on the surface and in hollows ** If complete air removal is achieved U. Kaiser 05/2011

15 Comparison of separations of non-condensable gases (NCG) in porous loads and hollow instruments Steam NCG Condensate porous cotton pack ml critical 0,2-0,3 ml critical Ratio of the critical NCG amounts: porous : hollow : U. Kaiser 07/2005 Internal volume in tubes and minimal invasive surgical (MIS-) instruments Thermo-sensor testing inside of metal tubes 1 m (Tube Volume = r 2 π x l = 3,14 ml) Metal wall Quick heat transfer (1) (2) Thermo-sensor 10 cm volume 0,314 ml 2 mm T (1) Non-condensable gases (NCG) < 1 ml become already critical in minimal invasive surgical (MIS-) instruments. (2) Thermo-sensor-tests in stainless steel tubes may create false positive results. Small volumes of NCG heat up very quickly through the metal walls which have a 100-times higher heat transfer velocity in comparison to plastic or textiles U. Kaiser 12/2012

16 Required steam quality for sterilizers Standard Maximum amount of NCG [ml] at 20 C at 1 bar allowed in 1 kg condensate Refers to a maximum volume % in the steam volume at 121 C and 134 C EN ml (3,5%) 0,000027% (0,00027 ) Calculation reference: Gas 20 C 1 bar 100 C 1 bar 121 C 2 bar 134 C 3 bar 1 kg steam [liter] 1244 l 1700 l 898 l 618 l NCG [ml] 35 ml 48 ml 24 ml 17 ml U. Kaiser 08/2009 Potential risks during a fractionated vacuum steam sterilization process 1. Unsatisfactory air removal during the fractionated vacuum cycle (remaining air in the sterilization chamber) 2. Leakages on door seals, valves and other devices (air returns into the chamber after the last vacuum cycle) 3. Air transfer through the door seal, if the sealing is pneumatically actuated (if steam is used to pressurize, the sealing problem does not occur) 4. Non-condensable gases are introduced together with steam (malfunction which is usually undetected during the sterilization cycle) After sterilizer and eventually steam generator are switched off, noncondensable gases develop in the pipes between steam generator and sterilizer and in the steam generator, and get into the sterilizer after starting again U. Kaiser 11/2005

17 Non-condensable gases (NCG) in steam Type of gas Origin Effect Elimination air ca. 80% N 2 20% O 2 air ca. 80% N 2 20% O 2 carbon dioxide CO 2 hydrogen H 2 Superheated steam dissolved air in water (ca. 25 ml air per 1 l water) In steam boilers and steam pipes before start-up water containing hydrogencarbonates corrosion of metals pressure reduction in steam pipes Hydratization of porous goods (heat generation by taking up water) The produced amount of air depends on the supply of injected water in the steam vessel. (air peaks after water injection) When not in operation steam boilers and steam pipes fill up with air During the heating process, CO 2 and carbonate salt (white covering) are formed Ca(HCO 3 ) 2 CaCO 3 + CO 2 + H 2 O (Invisible for NCG detectors, because CO 2 dissolves in condensate) permanent small amounts of NCG and of flying rust in iron pipes (seldom) The superheated steam is unable to condensate until it is reaching its condensation point. Degasing of the injected water by heating up to C before injecting into the steam vessel During start-up steam pipes need to be purged by a warm-up cycle to remove the air. Degasing or de-mineralization by Ion-exchange or possibly together with Reversed Osmosis (RO) RO alone is not sufficient! Adjust ph-value > 7 in buffer solutions Remove chloride and other chelate complexing agents from feeding water Install cooling line after pressure reduction. Don t dry porous goods with dry heat before the sterilization. Conditioning in normal humidity is required or moisten the goods before sterilization U. Kaiser 07/2011 Recording of non-condensable gases (NCG) concentration in steam % NCG Injection of feeding water Time U. Kaiser 07/2011

18 Central Steam Supply branch pipe (e.g. kitchen) steam pipe Branch pipe (e.g. laundry) steam generator steam chamber feeding water sterilizer sterilizer source of feeding water heating At the beginning of the sterilization process steam generator, steam pipe and sterilizer have to be flushed with steam to remove the air. This can be tested successfully with the Bowie-Dick-Test (function test for the sterilizer, no sterility test) U. Kaiser 07/2007 Influence of time if non-condensable gases (NCG) entering the steam sterilization process cause a risk Pressure [bar] 4 NCG are taken out with following vacuum cycles and are not critical for sterilization performance. NCG being introduced during the warm-up-phase travel almost quantitatively into the packs of the loads and may harm the efficacy of sterilization processes depending on the type of load and the amount of NCG. Temperature [ C] fractionated vacuum BDS-Test 3,5 min NCG enter the chamber during the sterilization plateau period and are also not critical for the sterilization efficacy since the packs do not absorb steam anymore and therefore also no NCG air-removal Time [min] warmup-time sterilization cooling drying U. Kaiser 07/2005

19 Water pre-treatment for steam generation (1) 1. Softening process using a cation exchanger - Exchanges Mg 2+ and Ca 2+ against Na + - Regeneration by common salt (NaCl) 2. Reversed Osmosis - retains salts but lets all gases, e.g. air, CO 2, pass through the membrane 3. Mixed bed ion exchanger - Exchanges all cations and anions against H + + OH - (results in H 2 O) The water quality shall be measured with a conductivity meter, should not exceed 5 10 µs/cm and should be monitored continuously in the CSSD. This treated feeding water still contains dissolved air. 4. Degassing before steam generator feeding - heats up the water to C - degasses the water - no loss of energy because heat up in the steam generator is anyway necessary later on U. Kaiser 11/2010 Different steam generators 1. Steam generation in the sterilizer - directly in the chamber (small sterilizers) - steam generator outside of the chamber, but short pipe to the chamber by electric heating 2. Decentral steam generation - steam generator heating with oil, gas or electricity only for the sterilizer 3. Central steam generation - central (expensive water preparation) 4. Secondary steam generation - The primary steam is used as heating source (The feeding water must be treated for the steam sterilizer) U. Kaiser 11/2010

20 Water pre-treatment for steam generation (2) 1. Water softening in a reservoir with cation exchanger resin balls Resin Resin Resin Ca ++ Na + Ca ++ Na + Na Na + - Na + Na + Resin Resin Resin 2 Na + Ca ++ is exchanged against 2 Na U. Kaiser 07/2012 Pump to compensate the osmotic pressure Water pre-treatment for steam generation (3) 2. Reversed Osmosis with plastic membrane (filter) The membrane lets water, air and CO 2 pass, but no salt. before H 2 O after water with mineral salt O 2 N 2 Salzlösung H 2 O Osmotic pressure of the water level difference CO 2 salt water membrane distilled water salt water distilled water The salt water tries to become diluted by water flowing through the membrane, until the pressure of the water head stops the water flow. concentrated mineral salt solution demineralized water + dissolved air + CO U. Kaiser 09/2012

21 Water pre-treatment for steam generation (4) 3. Ion exchanger in a reservoir with cation and anion exchanger resin balls, removes all inioc salts from the feeding water for steam generation Resin Resin - Ca++ - Ca ++ (HCO 3- ) 2 H + OH - OH - + HCO HCO 3 - Resin Resin Resin - H + H + OH OH - Resin The salt ions are kept in the cartridge and therefore H + and OH - ions are released 2 H + 2 OH - 2 H 2 O U. Kaiser 07/2012 Water pre-treatment for steam generation (5) 4. Degasser removes the dissolved air steam feeding water Degasser steam generator P C no heat energy is lost U. Kaiser 07/2012

22 Measuring the conductivity Water conducts electricity, if salts (positive and negative ions) are dissolved in it. The more salt is dissolved, the higher is the conductivity. Therefore the conductivity is a measuring unit for the amount of dissolved salt in the water. The unit of conductivity is Siemens per cm. 1 S/cm = ms/cm = µs/cm AMP + - Example for the conductivity of water: Absolute pure water : 0,05 µs/cm bis 0,1 µs/cm Tap water: 300 µs/cm bis µs/cm = 1 ms/cm Sea water: appox µs/cm = 50 ms/cm Demineralized water for steam supply: 5 µs/cm (acc. EN 285) end flushing: < 15 µs/cm (acc. Guidelines of DGKH, DGSV, AKI) U. Kaiser 07/2012 Requirements for a successful sterilization process 1. Achievement of the kill kinetics, e.g.: F 121 C =15 min overkill in a steam sterilization process 2. Penetration of the sterilizing agent to all inner and outer surfaces PENETRATION Test of the: 1. Kill kinetics by parametric release and/or biological and/or chemical indicators 2. Use of a process challenge device (PCD) to test the worst case penetration conditions using biological or chemical indicators or themo-sensors inside the PCD U. Kaiser 07/2005

23 Pressure Dependence of Water Boiling Temperature; Temperature Dependence of Heat Capacity and Steam Volume Boiling Temperature [ C] [kpa] Pressure [bar] Overpressure [bar] Heat Capacity [kcal/ kg steam] Steam Volume [l/ kg steam] ,1-0, ,75-0, Remarks Typical vacuum in a sterilizer Pressure on a mountain at a height of m ,0 0, Standard pressure ,0 1, ,0 2, Standard sterilization procedure at 121 C Standard sterilization procedure at 134 C ,0 3, U. Kaiser 07/2005 Reasons for wet goods at the end of steam sterilization processes Reason Goods have been wet before packaging Condensate from the above goods is dropping down into the packages Wet steam, condensate aerosols enter the packages together with the steam Condensate at the package/ container is separated from the goods and accumulates to a condensate puddle at the bottom of the container or soaks the bottom part of the packaging At the end of the sterilization process steam remains in the package and condensates with gradual cooling Remedy Dry all goods to be sterilized before packaging Use completely covered metal container or cover each level of the sterilizer rack with a plate to let the condensate run outward Use a pressure reducing valve before sterilizer and condensate traps to dry the steam Wrap the goods with a water-absorbing material (absovlies; cloth) to keep the condensate in the near of the goods and to use the heat of the goods to evaporate the condensate Use pressure-difference-process and flushing with air to remove steam at the end of the sterilization process U. Kaiser 07/2005

24 Requirements for sterilization monitoring in steam sterilizers with fractionated vacuum 1. Validation / revalidation (annually) Test of the sterilizer at the manufacturer, after installation and substantial repairs = operation and installation qualification (OQ & IQ) = Commissioning Performance qualification of all processes / programs using worst-case load configurations = performance qualification (PQ) 2. Function test of the sterilizer (during each start-up) Function test at start-up of the sterilizer to prove air removal and steam penetration using a BD- and vacuum test. 3. Routine monitoring of each batch (in each cycle) Recording the basic technical parameters (for steam sterilizers: pressure and temperature versus time and monitoring of successful steam penetration) 4. Documentation using a quality management system (QMS) Sterilized goods must be released by trained personnel according to defined standard operation procedures (SOP) U. Kaiser 09/2010 Robert Koch Institute (RKI) Recommendation Requirements to the Hygiene during Reprocessing of Medical Devices, 10/2012 (1) Quote of chapter 1.4 Securing the quality of the reprocessing processes to be used (page 1251) The quality of the reprocessing is secured in dependence of the individual cleaning, disinfection and sterilization procedures by a) validation (consisting of installation [IQ], operation [OQ] and performance qualification [PQ]), b) regular routine monitoring (e.g. daily), c) batch-related routine monitoring, d) monitoring and checking of the process parameters, e) maintenance, calibration, if necessary adjusting, servicing and f) regular process validations (revalidation) g) event-related validation (performance qualification because of special reasons) J. Metzing 02/2013

25 Robert Koch Institute (RKI) Recommendation Requirements to the Hygiene during Reprocessing of Medical Devices, 10/2012 (2) Quote in attachment of annex 4 Special information for the use of biological indicators (page 1273) The requirement to check sterilizers with biological indicators half a year or every 400 batches, originates from an older chapter inspection of DIN for the operation of large steam sterilizers which has been withdrawn in the meantime. The new valid standard EN ISO including also small table top sterilizers has a larger scope and does not contain this specific requirement using biological indicators anymore J. Metzing 02/2013 Validation EN ISO describes the validation and routine monitoring of steam sterilization processes. It is valid for all processes used in industry, laboratories and health care institutions, up to disinfection of liquids and waste. Therefore the requirements of the standard are very general, since depending on the sterilization process (e.g. with or without fractionated vacuum) and the load configuration (e.g. instruments, liquids, waste) different monitoring methods have to be used. Therefore the general description of the validation and monitoring procedure in the standard always has to be adapted to process and load configuration J. Metzing 09/2010

26 Function test of the sterilizer Function test of the sterilizer at start-up Clause 12 of the validation standard EN ISO (Maintenance process effectiveness) quotes: : If the sterilization process relies on the removal of air from the sterilizer chamber in order to achieve rapid and even penetration of steam into the sterilizer load, a steam penetration test shall be carried out each day before the sterilizer is used. The standard does not prescribe a special test for routine monitoring, therefore usually two type tests described in the sterilizer standard EN 285 are used: Bowie-Dick-Test according to EN 285 Part 17 Hollow Load Test according to EN and EN 285 gke offers a test device for the BD- and the hollow load test simultaneously J. Metzing 09/2010 Routine monitoring of each batch Routine monitoring of each batch (1) In the validation standard EN ISO the following text is quoted: Routine monitoring and control shall be performed on each operating cycle. (each cycle = each batch) Steam penetration Clause 11: Product release from sterilization Procedures for the [ ] product release from the sterilization process shall be specified. This specification must define the condition that the sterilization process is conforming to specification (see 9.5.2, 10.3, 10.5 and 10.6). If one condition is not fulfilled, the product must be marked as faulty J. Metzing 08/2010

27 Routine monitoring of each batch (2) Therefore the standard EN ISO requests for routine monitoring: All critical parameters of each batch must be monitored and tested for sterility. The parameter steam penetration according 10.3 is depending on the complexity of the load, one of the most critical parameters and must be tested in each batch. gke offers for this monitoring special load-related PCD systems. These PCD systems must be adapted to the requirements of steam penetration in the load. Monitoring of steam penetration with air detectors is in instruments neither qualitatively nor quantitatively possible. The amount of non-condensable gases in steam is only a part of the steam penetration problem, the correct air removal of individually different complex instruments cannot be measured with air detectors J. Metzing 08/2010 Documentation using a quality management system (QMS) Information and documents, which must be available for release: Batch printout of the sterilizer with pressure and temperature over time Process indicators provide only information that the package has passed the sterilization process. No information about sterility. Prove of sufficient steam penetration (depending on the load) a. Use of biological or chemical indicators in packs to prove, if solid instruments are sterilized b. Use of Indicator systems in PCDs (Medical Device Simulator = MDS or Batch Monitoring System = BMS), if hollow instruments, complex loads or waste are sterilized c. Use of biological indicator suspension and/or temperature sensors if liquids are sterilized Compliance with release conditions must be batch-related documented U. Kaiser 09/2010

28 Central Steam Supply branch pipe (e.g. kitchen) steam pipe Branch pipe (e.g. laundry) steam generator steam chamber feeding water sterilizer sterilizer source of feeding water heating At the beginning of the sterilization process steam generator, steam pipe and sterilizer have to be flushed with steam to remove the air. This can be tested successfully with the Bowie-Dick-Test (function test for the sterilizer, no sterility test) U. Kaiser 07/2007 Different types of the Bowie-Dick-Test Comparison Europe - USA Country Standard Size [cm] Europe EN 285, chapter 17 Weight [kg] 25 x 35 x 20 7 kg ± 10% BD-Testprogram inside the sterilizer 134 C, 3.5 min or 121 C, 15 min Required method of simulation test Standard for test EN = EN-ISO name Steam penetration test Test method - Air removal - Leaks - Noncondensable gases USA AAMI/ANSI ST 79 ca. 24 x 35 x 29 4 kg ± 200g (± 5%) 132 C, 3 min ISO Air removal test - Air removal The American test package has approximately 1/2 of the weight of the European test package and is therefore less sensitive in testing the air removal and steam penetration U. Kaiser 10/2013

29 Air removal of porous and hollow goods using different steam sterilization processes BD-Test package according to EN pass + pass + pass Hollow load test according to EN pass _ fail _ fail + = penetration successful - = penetration not successful Pressure [mbar] Sub-atmospheric cycle according to EN 867-4, B.1 Trans-atmospheric cycle according to EN 867-4, B.3 with a sterilization temperature of 134 C Pressure [mbar] Trans-atmospheric cycle according to EN 867-4, B.3 with a sterilization temperature of 121 C From the publication Gömann/ Menzel/ Kaiser Central Sterilization 3/2001 Druck abs. [mb] Pressure [mbar] During the modification of the European Standard EN 285 for big sterilizers the hollow load PCD according to EN was included as standard-test additionally to the BD-Test pack Time [min] Time [min] Time [min] U. Kaiser 07/2009 Compact-PCD - sectioned - Cap Chemical Indicator Teflon holder for indicators Metal capsule Stainless steel tube Outside case U. Kaiser 07/2005

30 Technical principle of the gke Compact-PCD This part is integrated into the inner part of the plastic case 10 ml air 90 ml steam 10% 90% Volume Detector Stainless steel tube 1m Plastic housing 0.2 ml 3 ml 100 ml U. Kaiser 10/2010 Limitations of biological and chemical indicators at different positions in steam sterilization cycles Biological and chemical indicators can only test the kill ability of steam (temperature vs. time), test of noncondensable gases in the chamber is not possible. Steam Inside of the pack indicators can test if there is steam penetration to the surface of the instrument. The indicator can check the surface of a hollow device but cannot check steam penetration inside of the instrument. Process indicator, provides only logistic information, that the pack has passed the process, no sterility monitoring U. Kaiser 03/2013

31 Process Challenge Devices (PCDs) for different applications Reference is simulated by Process Challenge Device Medical Device Medical Device Simulator MD Batch Using the simulation test procedure of the standard DIN MDS Batch Monitoring System MD MD MD BMS Defined Load Configuration J. Metzing 12/2010 Class 2 indicators for type tests, MDS 1 and BMS 2 MDS or BMS test-system are used to monitor sterility of a medical instrument or load in sterilization processes: P rocess C hallenge + Indicator system = Indicator D evice An indicator is an object in its final form in which it is intended to be used. (Definition in EN-ISO for class 2 indicators) 1 MDS = Medical Device Simulator 2 BMS = Batch Monitoring System U. Kaiser 03/2007

32 Use of Process Challenge Devices (PCDs) (1) 1. As type test to monitor the sterilizer specifications PCD as type test Hollow load helix test according EN for sterilizer according standard EN 13060, type B (table top sterilizer) BD-Test 7 kg cotton pack (EU) since 2008 in addition Helix test according EN EN 285 (large sterilizer) BD-Test 4 kg cotton pack (USA) AAMI/ANSI ST U. Kaiser 05/2014 Use of Process Challenge Devices (PCDs) (2) 2. As batch monitoring system to check the sterilization of a load Hollow loads can be validated only by direct inoculation at the worst-case location For routine monitoring PCDs must be used This PCD must have higher requirements of steam penetration than the load itself (worst-case conditions) to monitor each cycle under worst-case conditions. The standard DIN describes a method to compare a PCD with an instrument A PCD validated using the method according DIN can be used as a batch monitoring system (BMS) outside of packages for batch release U. Kaiser 05/2014

33 Use of batch monitoring systems Selection and Release Batch monitoring systems are used, if a device, i.e. sterilizer or washer/disinfector, does not monitor and document all critical variables. A batch monitoring system can monitor one, several or all critical variables, so that the result of a batch monitoring system allows the release of a load (i.e. in a steam sterilization process monitoring of air removal, temperature-time-integral (F 0 -value) and the condensation of steam to water) is sufficient. If the load consists of different products, the validation of the batch monitoring system must relate to the most difficult load configuration for a cleaning or sterilization process U. Kaiser 03/2014 Definition of PCDs Class 2 indicators are defined in ISO as special indicators where the specifications are defined in other standards, i.e. EN ISO , -5 or -6. The test is always a combination of a PCD with a phyiscal, chemical or biological indicator. They must be tested always in combination of PCD + indicator. In steam sterilization processes this test does not only check the critical variables temperature, time and water, as class 5 and 6 indicators do, but in addition air removal and steam penetration is tested U. Kaiser 02/2014

34 1. Porous PCDs Design of PCDs (1) Porous PCDs are made of cotton or paper packs or combinations using different materials. If cotton or paper packs are used, it is very important to have a uniform porous structure. If holes are put into paper packs to insert indicators, the holes totally destroy the penetration characteristics of a porous load and make them very easy to pass U. Kaiser 02/ Hollow Load PCDs Design of PCDs (2) Penetration characteristics of hollow loads depend on length, diameter, wall thickness and material of tubes. Tubes with large diameters are more difficult to be penetrated with steam than tubes with smaller diameters. 1 Tubes with both ends open have the most difficult penetration and sterilization area in the geometrical middle of the tube but in these areas indicators usually cannot be placed. Therefore surrogate test devices are available on the market where one end is closed and indicators can be positioned at the worst case location to be penetrated at the closed end. These areas at the end of a tube must have the same volume and diameter as the tube itself. 1) Investigation of Air Removal from Hollow Devices in Steam Steriliatzion Processes, U. Kaiser and J. Gömann, Central Service Volume 6,1998, p U. Kaiser 02/2014

35 Design von PCDs (3) The steam penetration difficulty of a helix-pcd test depends on length, diameter, material and wall thickness of the tube and the free capsule volume. The larger the indicator capsule volume, the less is the sensitivity of the test device. wrong helix construction easily penetrated by one steam pressure cycle same tube without capsule is not penetrated under the same process conditions X worst-case location correctly designed Helix-PCD simulating a tube U. Kaiser 05/2014 Consequence of the volume of the indicator capsule on the sensitivity of a PCD (1) Beginning of air removal from 1000 to 100 mbar air (1000 mbar) air (100 mbar) with a pressure reduction from 1000 to 100 mbar 90 % of the air is removed from the hollow device H. Keßler 03/2014

36 Consequence of the volume of the indicator capsule on the sensitivity of a PCD (2) Steam feeding (1000 mbar) The indicator is already reached with steam after one air removal cycle from 100 to 1000 mbar air (1 bar) air (0.1 bar) steam H. Keßler 03/2014 Robert Koch Institute (RKI) Recommendation Requirements to the Hygiene during Reprocessing of Medical Devices, 10/2012 (3) Quote in attachment to annex 4 Special requirements for the use of chemical indicators (page 1274) PCDs have been developed to simulate a special difficulty of steam penetration in a sterilization process [ ] There is no universal PCD to be used for all processes and applications J. Metzing 02/2013

37 Test method to check if a Medical Device Simulator (MDS) or Batch Monitoring System (BMS) is equivalent to a Medical Device (MD) or defined load according DIN Process Upgrade process MDS or BMS Fail sterilization not successful Pass sterilization successful mb Downgrade process Fail BI growth = sterilization not successful Inoculated instrument (for MD) or reference load (for BMS) Pass no BI growth = sterilization successful MDS or BMS acceptable Vacuum cycles J. Metzing 05/2012 Conceptual approaches for routine monitoring with a batch monitoring system (BMS) Validation of the defined load with the sterilizer Sterilizer Conformity test with the standard type test to check the sterilizer specification (Commissioning) Defined load Sterility proof Validation of a batch monitoring system (BMS) to a defined load for routine monitoringng Monitoring Type test, i.e. BD-Test or hollow load test Validated batch monitoring system (BMS) Commissioning + Performance Qualification = Validation of a process. After validation the process is secured using a type test for routine monitoring to check the sterilizer. Routine monitoring with a batch monitoring system (BMS) that is validated against a defined load, without a performance test of the sterilizer U. Kaiser 07/2009

38 Pproduction : Expiry: OP3 PK Use of a batch monitoring system (BMS) The result of the sterilization procedure has to be documented on each pack with a label on top to inform the OR nurse opening the pack Steam A package indicator is not required anymore using a BMS validated to a load. The process challenge device (PCD) is designed to simulate a full load (BMS) and can monitor penetration into hollow devices as long as it is more difficult to penetrate than instruments in packs. Process indicator, provides only logistic information, that the pack has passed the process, no sterility monitoring U. Kaiser 02/2011 Different types of monitoring systems testing the efficacy of steam sterilization processes Type of test Monitoring potential Limitations 1 Parametric release: recording the temperaturepressure-time window 2 Biological indicators 3 Non-biological all parameter integrating indicator (emulates biological indicators according to EN class D) 4 Bowie-Dick-Test Temperature-timewindows checking the kill of germs Steam penetration test for porous loads and solid instruments No ability to test the chamber for non-condensable gases in steam coming from various sources Test only at the place where indicators are located No steam penetration test for complex hollow devices 5 Specific process challenge device (PCD) simulating complex hollow devices according to EN Steam penetration test of solid instruments, porous loads and hollow devices and kill kinetics Comparison is necessary between the penetration characteristics of the hollow devices to be tested and the PCD used U. Kaiser 07/2005

39 Robert Koch Institute (RKI) Recommendation Requirements to the Hygiene during Reprocessing of Medical Devices, 10/2012 (4) Quote in attachment of annex 4 Information for the use of biological and chemical indicators (page 1273) A successful validation does not secure that the sterilization conditions are always kept during routine operation. [ ] Therefore suitable routine monitoring must be carried out (see EN ISO 14937, clause 10), to secure that the validated process is always carried out J. Metzing 02/2013 Robert Koch Institute (RKI) Recommendation Requirements to the Hygiene during Reprocessing of Medical Devices, 10/2012 (5) Quote of checklist Implementation and operation of small sterilizers to reprocess medical devices Heading Batch-related tests (page 1272) Test of the complete and correct process run - Test and documentation of the result of the process indicators (class 1) - Test and documentation of the process parameters - Test and documentation of the result of the indicator Critical A instruments: without PCD (class 5) Critical B instruments: with PCD, e.g. helix test (class 2) J. Metzing 02/2013

40 Robert Koch Institute (RKI) Recommendation Requirements to the Hygiene during Reprocessing of Medical Devices, 10/2012 (6) Quote in attachment of annex 4 Special requirements for the use of chemical indicators (page 1274) The level of difficulty of class 2 indicators is depending on the combination of the chemical indicator and the PCD components. Each variation, e.g. the use of another indicator, can cause that malfunctions are not detected. Therefore only components defined from the manufacturer can be combined. This applies also for systems with a reusable PCD J. Metzing 02/2013

41 Technical information of cleaning processes in washer-disinfectors (WDs) II Cleaning Monitoring 1. Complexity of monitoring 2. Current situation in the standards 3. Protein test methods 4. Tests with cleaning indicators 5. gke Cleaning indicators 6. Test of ultrasonic cleaning basins U. Kaiser 04/2014 Differences of sterilization and cleaning monitoring indicators 1. Indicators for sterilization monitoring : Class 5 and 6 indicators according EN ISO and biological indicators according EN ISO monitor all three critical variables (temperature, time, water) for a successful steam sterilization process. A sterilization indicator proofs sterility at the place located inside the sterilizer. 2. Indicators for cleaning monitoring In comparison to sterilization there are no defined critical variables for cleaning. Which variables are critical, depends in the contamination of the instruments and the process selected: mechanical variables: e.g. brushes, ultrasound, spray jet chemical variables: e.g. temperature, time, water quality, cleaning agent Therefore depending on the contamination totally different cleaning programs are used: A cleaning indicator cannot be specified for the necessary parameters required but must be selected for each individual cleaning process. The selected cleaning indicator works correctly, when the cleaning indicator is not washed off completely anymore, if the cleaning process has changed getting worse results U. Kaiser 05/2014

42 Complexity of monitoring situation Differences of: - contaminations - pretreatment of instruments - cleaners - used water quality (tap, softened, demineralized water) - mechanical cleaning - manual - ultrasonic - automatic - location inside the washer/disinfector (WD) - Spray shadows - Different mechanical force of the spray within the WD - Different cars - Various trays with multiple instruments - complexity of instruments - Splits - Screws - Lumen - Flushing channels U. Kaiser 08/2011 Current situation of cleaning monitoring - in the ISO standard series - part 5 lists 19 test soils collected from different countries - no test soils are defined as a reference - no test method is defined to compare soils with each other - Test systems available on the market using different test methods - various organic soils or artificial indicators - use undefined PCD with several constructions - Mainly visible inspection or a magnifying glass is used in CSSDs - Measurement of the remaining protein concentration (3 methods) - Existing cleaning indicator with PCDs have no reference in terms of - difficulty of soil removal - Use of PCDs simulating splits and covered areas U. Kaiser 01/2013

43 Annex Used Test Soils (selection) according to ISO/TS ) A Sheep blood with protamine sulfate 2) B Nigrosine with flour and egg 3) C Nigrosine with flour, egg and potato starch 4) G Semolina pudding 5) G Sheep blood 6) G Egg yolk 7) H Mucine and bovine albumine 8) H Corn starch 9) N Sheep blood with egg yolk and mucine 10) P Flour with egg, wallpaper paste and ink 11) Q Sheep blood with egg, wallpaper paste and ink Danja Kaiser 05/2014 Protein test methods 3 different methods are used which all test for chemical colour reaction with proteins. All 3 methods can proof small amounts (0,05 0,5 µg/ml): 1. Ninhydrin test Disadvantage: Chemical is toxic 2. Biuret-Method (NaOH + CuSo 4 ph < 11) 30 min at 37 C 3. Ortho-Phthaldialdehyde (OPA-Method) Possible sampling 1. Sweep the surface with a piece of cotton wool (problem, which amounts are removed and which remain? 2. Sweep/flush surfaces/canals with Na-Dodecylsulfate (SDS) 3. Shake instrument in a polyethylene bag with SDS-solution * SDS is a detergent, which brings proteins into solutions. Detection 1. Visual differentiation of various colour changes on surface (not qualitative) 2. Comparison of different calibrated solutions 3. Use of spectrophotometer to measure the sorption in solutions Problems Measurement of the protein concentration in hollow devices is difficult to quantify, (which limit amounts of the protein concentration on surfaces are tolerable?) No information about the limit amount of other soils available U. Kaiser 11/2011

44 ATP bioluminescence test method to proof rest contamination on medical devices ATP (Adenosine tri-phosphate) is an energy delivery system in all living organisms. During the conversion to ADP (Adenosine di-phosphate) energy is released, the ATP discharges. With Firefly reagens (luciferin/luciferase-complex) it sends out light during this discharge and can so be quantitatively measured. Contaminants (proteins) contain ATP. However, the evaluation of rest contamination by measuring the ATP is not reliable because of the following reasons: ATP discharges permanently to ADP, that means the ATP-concentration decreases already before cleaning. ATP can be washed off without washing off the contaminants. The absence of ATP therefore does not allow the conclusion of a successful cleaning process U. Kaiser 05/2014 Tests with cleaning indicators The optimal cleaning indicator shall have the following characteristics to monitor the cleaning mechanisms: Fixation on carrier surface to simulate spray shadows Dissolution in water / detergent Reaction on Enzymes ph-value Tensides Temperature Cleaning time Long-term reproducibility Non-pathogenic Fair price for use in every batch Easy handling and documentation U. Kaiser 05/2014

45 Design of cleaning indicators - Cleaning indicators are not yet standardised - There is no test method available to test - There are no reference test soils available (The approx. 20 soils listed in ISO/TS are quite different in their cleaning characteristics and are not specified for tests.) - There are quite different cleaning indicators available on the market - Different materials - blood-based - chemical systems - Different carriers - stainless steel - plastic foils - Different PCDs - with/without/different covers - with/without/different splits - different flow-through PCDs - Different wash-off characteristics of the indicators based on: - enzymes - ph - detergents of the cleaning agent - temperature - mechanical force - water quality U. Kaiser 05/2014 Robert Koch Institute (RKI) Recommendation Requirements to the Hygiene during Reprocessing of Medical Devices, 10/2012 (1) Quote of checklist Implementation and operation of washer-disinfectors (WD)..., Heading Documentation of the WD performance... (page 1268) Definitions for routine monitoring: - If applicable, selection of a suitable PCD - [ ] - Procedure to confirm the cleaning success J. Metzing 02/2013

46 Robert Koch Institute (RKI) Recommendation Requirements to the Hygiene during Reprocessing of Medical Devices, 10/2012 (2) Quote of checklist Implementation and operation of washer-disinfectors (WD)..., Heading Batch-related tests (page 1269) Documentation of the relevant process parameters: - Dosage of chemicals - Process run (time) - Process temperatures - If applicable, flushing pressure (guarantee of flushing) Visual inspection of the goods: - Cleanliness (if applicable, with the use of a cleaning indicator, e.g. at critical B medical devices) - Instrument not damaged - Drying, residual moisture J. Metzing 02/2013 Cleaning indicator positioning has to be done taking the following mechanical influences into consideration: a) in the chamber of a washer disinfector (WD) Load configuration spray shadows Instrument design splits, areas hard to reach Cart design spray arms, nozzles positioning of the indicator at the place most difficult to clean b) in flow-through connected lumens simulating flow characteristics with different PCDs use indicators to simulate real soil fixation connect the hollow flow PCD parallel or in series to the endoscope U. Kaiser 05/2012

47 gke Spray Test Rig gke had to develop a test method to compare different soils and indicators Danja Kaiser 03/2013 Construction of the gke Spray Test Rig (1) Danja Kaiser 03/2013

48 Construction of the gke Spray Test Rig (2) Danja Kaiser 03/2013 Construction of the gke Spray Test Rig (3) The spray rig provides removal information as a summary of dissolution and mechanical force. The cleaning efficacy is influenced by the - type of cleanser - temperature - spray time - ph - conductivity - mechanical force - physical flow conditions - nozzle configuration - flow speed - pressure - distance between spray nozzle and instrument - distribution of the spray jet at the contact point of the instrument Danja Kaiser 12/2012

49 Video: Example with Sheep Blood Danja Kaiser 01/2011 gke Clean Record Cleaning Indicators for washer-disinfectors Level 4 Multi-Level (MLC) Level 2, 3, 4 Level 3 Level 2 Level U. Kaiser 11/2012

50 gke Clean Record Cleaning indicators for bedpan washers U. Kaiser 04/2013 Test soils according to ISO/TS Germany, Annex H, Mucin, bovine albumin Germany, Annex G, Sheep blood % test soil left on the plate, with different spray time 10 sec 20 sec 30 sec 1 min 3 min 5 min 10 min Austria, Annex A, Sheep blood, protamine sulphate Austria, Annex B, Nigrosine, flour, egg Austria, Annex C, Nigrosine, flour, egg, potato starch United Kingdom, Annex P, Flour, water soluble wallpaper paste, egg, black ink Test results of the spray test rig (1) with demineralized water flow rate 1,0 l/min at 55 C W-WA-L1 Level Germany, Annex G, Semolina pudding United Kingdom, Annex Q, Sheep blood, water soluble wallpaper paste, egg, black ink W-WA-L2 Level United Kingdom, Annex N, Egg yolk, sheep blood, mucin Germany, Annex H, corn starch Germany, Annex G, egg yolk W-WA-L3 Level W-WA-L4 Level Danja Kaiser 05/2014

51 Test results of spray rig tests (2) with demineralized water, using 0,3 % alkaline detergent from manufacturer 2, flow rate 1,0 l/min at 55 C Test soils according to ISO/TS Germany, Annex H, Mucin, bovine albumin Germany, Annex G, sheep blood W-WA-L2 Level Process time in seconds % test soil left on the plate 10 sec 20 sec 30 sec 1 min 3 min 5 min 10 min Austria, Annex A, sheep blood, protamine sulphate Austria, Annex C, Nigrosine, flour, egg, potato starch W-WA-L1 Level United Kingdom, Annex P, Flour, water soluble wallpaper paste, egg, black ink Germany, Annex G, egg yolk Austria, Annex B, Nigrosine, flour, egg Germany, Annex G, semolina pudding United Kingdom, Annex N, egg yolk, sheep blood, Mucin W-WA-L3 Level United Kingdom, Annex Q, Sheep blood, water soluble wallpaper paste, egg, black ink Germany, Annex H, corn starch W-WA-L4 Level Danja Kaiser 05/2014 Advantages of the spray rig test method With this test method and standardized test procedures 1. cleaning indicators can be validated against standard reference soils. 2. different cleaning indicators on the market can be compared under the same conditions. 3. different cleanser on the market can be compared under the same conditions. 4. test soils of the standard ISO/TS can be tested and divided in different levels of difficulty. 5. Efficacy of washer/disinfectors (WDs) can be measured under defined test conditions Danja Kaiser 05/2014

52 gke Clean Record Holder for cleaning indicators for reproducible placement of the cleaning indicators in WDs for batch monitoring U. Kaiser 01/2013 Washer-disinfector (WD) test with gke cleaning indicators Application to test a WD gke cleaning indicators can be distributed in the whole WD chamber and provide an information about the spray conditions at different locations. The mechanical effect of the spray jet in the WD may differ because: The test location is sprayed directly or only indirectly The spray jet is reflected The load and/or the cart causes spray shadows Spray nozzles can be clogged The spray arm can change its rotation speed or stop The spray effect is reduced by foam J. Metzing 05/2012

53 Reasons for reduced cleaning efficiency If test results are worse in comparison to previous batches, two reasons are possible: Monitoring by WD possible? Spray jet (impulse = force x time) has become weaker The chemical efficiency of the detergent has become lower yes (depending on the WD type) Program failure (wrong time) Cart not locked correctly Remaining water from previous step because of clogged dirt strainer Spray arm blocked or wrong rotation speed Program failure (wrong temperature) Wrong dosage amount Changed water quality Spray shadows, reflected spray jet Wrong detergent no Clogged spray nozzles Spray efficiency reduced by foaming Reduced pump efficiency Expired detergent Mixed-up detergent canisters Dosing system contains air bubbles Wrong programm (not adapted to the load) Wrong program J. Metzing 10/2013 Wash-off characteristics of a soil depending on spray strength and time (1) Spray Rig Test Parameter Spray strength [l/min] Enzymatic mild alkaline cleaner (ph=10,5) at 55 C, demineralized water, full cone nozzle, spray angle 30 Time 10 s 20 s 30 s 1 min 3 min 5 min 10 min 0,5 1,0 1,5 2,0 2,5 The red indicator colour shows the wash-off characterstics of a soil with different spray strength at different locations in a WD chamber over time U. Kaiser 09/2013

54 Wash-off characteristics of three soils depending on spray strength and time (2) Spray Rig Test Parameter demineralized water, 55 C, spray nozzle 30 CleaningAgent Enzymatic detergent from manufacturer 3, ph = 6,5 Spray strength [l/min] Time 0 sec 10 sec 30 sec 1 min 3 min 5 min 10 min 0,5 1 1,5 2 2,5 The three indicator colours show the wash-off characteristics of differently strong adhering soils tested with different spray strength over time U. Kaiser 02/2013 Comparison of the 4 gke cleaning indicators under equal test conditions with cleaning agent 1 (ph 6,5 + enzymes) Spray Rig Test Parameter Cleaning indicator demineralized water, 55 C, flow rate 1 l/min, full nozzle, spray angle 30 Flow time 0 min 10 sec 30 sec 1 min 3 min 5 min 10 min Level 1 Level 2 Level 3 Level U. Kaiser 02/2013

55 Comparison of the 4 gke cleaning indicators under equal test conditions with cleaning agent 2 (ph 10,5 + enzymes) Spray Rig Test Parameter Cleaning indicator demineralized water, 55 C, flow rate 1,0 l/min, full nozzle, spray angle 30 Flow time 0 min 10 sec 30 sec 1 min 3 min 5 min 10 min Level 1 Level 2 Level 3 Level U. Kaiser 02/2013 Influence of different tap water qualities on the cleaning process, using the same softening procedure Spray Rig Test Parameter 1,0 l/min, 55 C, Spray nozzle 30 Indicator MLC, batch CleaningAgent Mild alkaline cleaner from manufacturer 2, 0,5 %, ph=10,5, with enzymes Spray time 0 min 10 sec 20 sec 30 sec 1 min 3 min 5 min 10 min Type of water Demineralized water < 1 µs/cm Tap water at 5 dh Tap water at 15 dh Tap water at 25 dh Tap water at 25 dh, softened U. Kaiser 05/2014

56 Requirement: How to select a cleaning indicator? (1) The cleaning process has to be validated in advance. Definition of a validated process: The prozess is effective (it works ) and it is reproducible (but must not change during daily operation). Therefore suitable routine monitoring is necessary. Selection of a suitable cleaning indicator: To secure the reproducibility of the validated cleaning procedure, a cleaning indicator must be selected for routine monitoring. Which cleaning indicator is suitable? J. Metzing 02/2014 How to select a cleaning indicator? (2) Process design Process validation Selection of cleaning indicator (WI) The program is suitable for all goods incl. hollow devices and instruments with splits. Test WI with a validated process use easier WI Required result: WI should be washed off. WI washed off? No WI too difficult Tip: Reduce the amount of detergent to simulate a wrong dosage or stop the cleaning process before it has finished. Yes In Inder the past Vergangen the Test selection WI with heitawurde of a cleaning oft die indicator Auswahl has been eines faultyfinished process Reinigungsindik at this stage. ators an dieser Stelle schon beendet. Required result: Yes WI should NOT be washed off. WI washed off? WI too easy use more difficult WI The WI is suitable for the validated process. If the process has changed, the WI-selection has to be repeated. Cleaning indicator suitable No = required result J. Metzing 04/2014

57 How to select a cleaning indicator? (3) Inside of a WD chamber different strengths of spray jets occur at different locations. In addition the cleaning efficacy depends on the spray time. Spray strength Spray time [min] J. Metzing 04/2014 gke Clean Record Hollow Flow PCD to monitor the flush connections in WDs 2 mm 3 mm split width 4 mm Including three adapters with 3 different split widths (2, 3 and 4 mm) in order to simulate different flow characteristics U. Kaiser 03/2013

58 Cleaning of lumen instruments Since cleaning inside a WD chamber is not efficient inside hollow instruments, they must be flushed by connecting them directly with a tube connector J. Metzing 12/2012 Connection examples of hollow devices and gke Hollow-Flow-PCD Connection in series Parallel connection PCD hollow device hollow device PCD PCD hollow device Allows monitoring of the flow through the hollow device The flow is monitored checking the pressure in the connection pipe, but the flow through the hollow device is not monitored U. Kaiser 12/2012

59 CleaningAgent Alkaline detergent, 0,5 %, ph = 7,7, with enzymes Water quality Demineralized water Flow rate 1,0 l/min 3,0 l/min Split width HF-PCD 2 mm 3 mm 4 mm 2 mm 3 mm 4 mm Flow time Influence of the splith width of the Hollow-Flow (HF)-PCD on the cleaning process at two different flow rates (1) 10 sec 30 sec 60 sec 3 min 5 min 10 min U. Kaiser 04/2014 Cleaning Agent Alkaline detergent, ph = 10,5 Water quality Demineralized water Flow rate 1,0 l/min 3,0 l/min Split width HF-PCD 2 mm 3 mm 4 mm 2 mm 3 mm 4 mm Flow time Influence of the splith width of the Hollow-Flow (HF)-PCD on the cleaning process at two different flow rates (2) 10 sec 30 sec 60 sec 3 min 5 min 10 min U. Kaiser 04/2014

60 Documentation of the test results of gke cleaning indicators The indicators are selfadhesive and can be documented J. Metzing 05/2012 Test of ultrasonic cleaning basins Ultrasonic waves are not all over effective in the basin volume. At the nodes of the standing waves less mechanical force is transferred, while at the loops the highest mechanical cleaning force is introduced into the liquid volume. When the frequency is changed, nodes and loops change, so that a more homogenous cleaning performance is achieved in the total volume. Alternatively the instruments to be cleaned can be moved inside the basin. The local performance can be tested with thin aluminum foils or plane indicators (see picture) U. Kaiser 05/2014

61 gke Clean-Record Cleaning indicators and holder for Ultrasonic basins The position of the indicator can be adjusted horizontally, vertically and at the bottom inside the cleaning basin U. Kaiser 05/2014 Cleaning in Ultrasonic bath (Bandelin RK 102 H) at 55 C with demineralized water and enzymatic neutral cleaner (ph=6,5) Cleaning time 2 min min min U. Kaiser 04/2014

62 Cleaning in Ultrasonic bath (Bandelin RK 102 H) at 55 C, with demineralized water and enzymatic mild alkaline cleaner (ph=10,5) Cleaning time 2 min 5 min 10 min U. Kaiser 04/2014

63 Basics Biological indicators 1. Special spore types to monitor different sterilization processes 2. Definition of the D-value 3. Definition of the resistence (F bio -value) 4. Definition of the Sterility Assurance Level (SAL) 5. Dependence of the Sterility Assurance Level on the incubation time (RIT) 6. Direct inoculation of instruments to test sterility of worst-case locations 7. Comparison of biological and chemical indicators 8. Construction of SCBIs to be used in PCDs U. Kaiser 10/2013 Test of sterilization processes with biological indicators (BI) (1) Alive spores (BI) are introduced in a sterilization process to check, if they are inactivated at the end of the process. When the process is successful, all BIs are inactivated. It cannot be determined visibly, if they are alive or dead, therefore several methods are used to proof if they are inactivated. Germs replicate every min if they have ideal growth conditions. Vegetative cells replicate but are not very stable and die within a period of 1 2 months. Some of them form spores, they survive without having food for several years. Those spores are used for biological indicators (BI). According to the validation standard EN ISO spores have to be selected which are more difficult to inactivate than pathogenic microorganisms known. Depending on the type of sterilization process their speed of inactivation is quite different, therefore different reference spore types are used for individual sterilization processes. Spore type Sterilization process to be checked ATCC*-No.: 1. B. Atrophaeus Dry heat, EO FO, Steam (for disinfection only) Incubation temperature C 2. G. Stearothermophilus Steam, FO, H 2 O C 3. B. Pumilus γ- and cobalt radiation C * ATCC = American Type Culture Collection U. Kaiser 11/2011

64 Test of sterilization processes with biological indicators (BI) (2) Even each strain listed in the table before has no defined resistance to one of those sterilization processes, but the resistance characteristic depends on the replication and sporulation manufacturing process. Therefore the strain alone does not provide defined information how fast BIs are killed in a process. Therefore each biological indicator batch must be provided with a certificate where the manufacturer has to publish information about the resistance of the biological indicator. The total resistance of a biological indicator is called F Bio -value and determined by its D-value and lg population. F Bio = lgpop x D process F Bio Pop D Process CfU = resistance of a BI (time until the number of spores on the BI is reduced to average 1 CFU) = number of spores = Decimal reduction time in a defined process = Colony forming unit Normally populations between and 1 million spores are put inside a BI. The D-value must be measured in a special test sterilizer called Resistometer and is different for each batch and sterilization process. The D-value is the time or dose necessary to inactivate 90 % of the former alive germs. Details are described in the standard EN ISO series U. Kaiser 11/2011 Summary of the requirements for biological indicators used for routine monitoring in steam sterilization processes referring to the international standards: EN-ISO part 3 and USP XXIV having almost identical requirements: Description Volume 1. Test organism G. stearothermophilus 2. Strains ATCC 7953, 12980; NCTC etc. 3. Minimal population N 1,0 x 10 5 [CFU] * ; ** 4. Precision of the retrospective population determination 5. Precision of the population distribution within a batch - 50%; + 300% of the nominal population ± 35% of the nominal population 6. Minimal temperature resistance for the carrier 134 C; 40 [min] or 5 C above the manufacturer stated exposure temperature 7. Resistance at 121 C D 121 C steam 1,5 [min]* 8. Precision of the D 121 C -value ± 0,5 [min] 9. F BIO-121 C -value = D 121 C x lg N 7,5 [min] 10 Temperature coefficient of the D-value tested between 110 C and 130 C Z 6 [ C] 11. Required packaging information Test organism, strain, D 121, Z, N, manufacturer, batch-no., expiry date, sterilization procedure * only valid for routine monitoring, not required for validation or special applications ** ampoules with growth media can have a lower population, if the F 121 -value conforms to the requirement of U. Kaiser 06/2011

65 EN ISO parts 1 6 Biological indicators (BI) Part 1 Part 2 Part 3 Part 4 Part 5 Part 6 (under development) General requirements for BI Self-contained biological indicators* and indictor strips for ethylene oxide sterilization processes Self-contained biological indicators and indicator strips for moist heat sterilization processes Biological indicators for dry heat sterilization processes Biological indicators for low temperature steam/ formaldehyde sterilization processes Biological indicators for hydrogen peroxide vapour sterilization processes (To be published later) * Self-contained BI (= SCBI) are BI with growth media which can be incubated in a CSSD U. Kaiser 06/2011 Total resistance of biological indicators is depending on: (1) logarithm of the population (lgpop) (2) resistance of the germs (D-value) Total resistance of a BI = F BIO -value [min] = lgpop x D-value [min] The F BIO -value is the time to reduce the population to the mean value of 1 CFU (66% growth) % Growth Sterilization time 100 (lgpop-2) x D-value = survival 90 (lgpop-1) x D-value 66 lgpop x D-value 10 (lgpop+1) x D-value 1 (lgpop+2) x D-value 0.1 (lgpop+3) x D-value 0.01 (lgpop+4) x D-value = kill Population [CFU] D-value [min] F BIO [min] The indicator with the lower population has a higher total resistance but is less expensive U. Kaiser 06/2011

66 Sterility Assurance Level (SAL) 1 10 Number = of contaminated packs Number of total packs = 0,1= 10 1 [CFU/part] Number = Number = of contaminated packs Number of total packs of contaminated packs Number of total packs = 0,1= 10 1 = 0,01= 10 [CFU/part] 2 [CFU/part] S A L terility ssurance evel Number = of contaminated packs Number of total packs = 0, = 10 6 [CFU/part] EN 556-1: products sterilized in packs: SAL=10-6 [CFU/part] EN 556-2: sterile filling of liquids: SAL 10-3 [CFU/part] U. Kaiser 06/2008 Dependence of the Sterility Assurance Level on the incubation time (RIT) Manufacturers offer quite different instructions for use how long to incubate biological indicators (from 1 hour until 7 days). Why? Living spores in biological indicators are killed during sterilization. If sterilization processes are insufficient, spores stay alive and multiply afterwards during incubation. Besides living and inactivated spores also damaged spores can be present at the end of the sterilization process which are not able to replicate immediately. However, the damaged spores can repair themselves, but they need several days for repair. Afterwards they can replicate again. As a result biological indicators may start growing after several days again and may require longer sterilization times to assure a correct result. Therefore there is a requirement from FDA-USA to prove Reduced Incubation Time (RIT). Also there is a standard draft ISO/TS (MIT = Minimum Incubation Time) under progress for the same subject U. Kaiser 02/2014

67 Different presentations of biological indicators There are 4 different presentations of biological indicators (BI) available on the market which may all contain the same spore type: 1. Biological indicator strips 2. Self-contained biological indicators 3. Biological indicator suspensions 4. Biological indicator ampoules U. Kaiser 12/2011 Biological indicator (BI) strips Filter paper is inoculated with spores containing a population of colony forming units (CFU) and protected with a glassine envelope which is permeable to the sterilization agent but protects the BI after sterilization against contamination. The BI strip is put in the sterilizer together with the load. After sterilization it cannot be observed if the spores inside the envelope are killed or not. The BI has to be brought into a microbiological lab, over there opened aseptically under a flowhood and transferred into growth media (soya broth) and transferred into an incubator under a defined temperature (called incubated). After some time it becomes visible if the germs will grow or not. The laboratory sends a test report of the result back to the CSSD. Alive spores = non sterile No spores growing = Sterile at the position where the BI has been located BI strip Flowhood Petri dish with growing spores U. Kaiser 11/2011

68 Self-contained biological indicators (SCBI) SCBIs are designed to get the information about the results after sterilization faster without using a microbiological laboratory. The filter paper spore disc is the same as described in 1. and is put on the bottom of the plastic vial, on top is a glass vial with growth media. The growth media contains a coloured ph indicator which changes its colour when the BI is growing. The SCBI is put in a sterilization process the same way like a BI strip. At the end of the process the SCBI is taken out and after cooling down the glass ampoule is cracked and the liquid growth media contacts the BI spore disc. Now the SCBI is put in an incubator for a time period according to the directions for use. When biological indicators remain alive, they replicate. During replication they create organic acids, changing the ph inside causing colour change. If colour change is observed, this is an indication that at least some germs remained alive and the sterilization process was not successful. No colour change indicates a successful sterilization process at the position inside the sterilizer where the SCBI was located U. Kaiser 09/2012 SCBI before and after sterilization result = sterile after sterilization and incubation, result = non sterile Components of an SCBI cap filter glass ampoule with growth media Plastic vial BI spore disc Instant-Mini-Bio-Plus self-contained biological indicator (SCBI) for immediate release of steam sterilization processes (no 3 hours incubation required) Closing filter below cap (filter paper) Different cap colours: 10 5 = light orange 10 6 = dark orange Class 1 chemical indicator (Process indicator) Ampoule with growth media (purple) and ph-indicator Colour change after incubation: STERILE = purple NON-STERILE = yellow-green Class 5 chemical indicator for immediate release PASS = black FAIL = yellow/yellow-brown Biological indicator spore disc U. Kaiser 09/2012

69 Biological indicator suspensions to inoculate lumen instruments inside worst-case locations Alive spores to check sterilization at the worst case location are available in water/alcohol suspensions. In microbiological laboratories these suspensions are transferred with a syringe into the worst-case locations inside complex instruments or sealed areas ( inoculation ). Afterwards the amount of spores being put in are washed out and counted to assure that the same amount of germs can be recovered ( validated recovery ). Afterwards the inoculation is repeated. The instrument is packaged and sterilized as usual and brought afterwards to a microbiological laboratory, opened aseptically and flushed with sterile water to get out the spores. Then the spores are checked, if they are alive U. Kaiser 02/2014 gke Steri-Record Stearo-Ampoules to monitor sterilization of liquids and waste The glass ampoule contains a 1.5 ml Geob. Stearothermophilus suspension with growth medium and ph-indicator, available with nominal populations of 10 5 and They conform with the standards EN ISO Storage conditions: 4 C - 8 C. liquids waste Stearo-Ampoules are used to monitor sterilization of wet or liquid materials like infusion solutions or culture media, or biological wastes in laboratories and hospitals. The ampoules are designed to be located in the liquid or waste during sterilization. With their small volume they precisely integrate the temperature profile of the liquids and fit into small vessels like test tubes U. Kaiser 02/2014

70 Pass/fail conditions of biological and chemical indicators (1) Example of pass/fail conditions of steam sterilization indicators with a stated value (SV) at 121 C Indicator Type Standard Fail-Time [min] Pass-Time [min] Biological indicators EN ISO ,5 13,5 Chemical indicators class 5 10,5 16,5 EN ISO Chemical indicators class 6 15,5 16,5 Biological indicators 0 4,5 13,5 min Chemical indicators class 5 Chemical indicators class 6 10,5 16,5 min 0 15,5 16,5 fail pass uncertain (pass or fail) U. Kaiser 11/2010 min Pass/fail conditions of biological and chemical indicators (2) Example of pass/fail conditions of steam sterilization indicators with a stated value (SV) at 134 C Indicator Type Standard Fail-Time [min] Pass-Time [min] Biological indicators EN ISO ,33 1 Chemical indicators class 5 2,25 3 EN ISO Chemical indicators class 6 2,7 3 Biological indicators 0 0,33 1 min Chemical indicators class 5 0 Chemical indicators class 6 2,25 3 min 0 2,7 3 fail pass uncertain (pass or fail) U. Kaiser 01/2011 min

71 Routine monitoring with biological indicators (1) Inside of steam sterilization processes there are no homogenous conditions, therefore biological or chemical indicators cannot be put outside of packages but must be put inside of packages at worst case sterilant penetration location. If tubes and complex MIS lumen instruments are sterilized, the most difficult areas are inside of such lumens. To check the sterility inside lumens, direct inoculation of those instruments must be carried out with biological indicator suspensions (see 3.), however this procedure is only done once during validation and cannot be repeated during routine monitoring. To assure sterilization of such complex instruments, during routine monitoring biological indicators have to be put in the worst-case location but direct inoculation is no alternative. To solve this problem, Process Challenge Devices (PCDs) are used to simulate instruments, called Medical Device Simulators (MDS) or simulate a whole load, called Batch Monitoring System (BMS). To assure that the simulation test devices are adequate to represent the instrument or the load, the test method in the standard DIN shall be used. This standard will be modified to become a new ISO standard which is accepted as a new work item already U. Kaiser 11/2011 Routine monitoring with biological indicators (2) To design a sensitive PCD, it is necessary that the capsule volume of the PCD has minimal internal free volume. gke has designed a special PCD where a SCBI can be inserted. This SCBI has a special design to minimize the internal volume to be used inside of such a PCD. Bild (Bio-PCD + SCBI rausguckend) A BMS can be used to monitor the whole batch under the condition the BMS has been validated and is more difficult than anything else inside of the load U. Kaiser 11/2011