routine control of washer-disinfectors - gke routine control of washer-disinfectors ... annex a,...

330 | from the field Central Service 5/2012

Routine Control of Washer-Disinfectors Introduction of an in-house standard for quality assurance1

T. Blechschmidt

• cleaning

• validation

• Wd

• routine control

• quality assurance

Key Words

1 ExtractfromafinalassignmentforSpecialistTrainingCourseIIIformanagersofCentralSterileSupplyDepart-ments(BadKreuznach,June2011toFebruary2012).

thomas Blechschmidt, orthopädie Bad hers-feld Gmbh, Am hopfengarten 16, d-36251 Bad hersfeld. e-mail: [email protected]

this paper describes the steps lead-ing up to the introduction of an in-house standard for routine control

of a washer-disinfector (Wd). there are no clearly defined specifications as to how this is done. But the operator must ensure that the results of performance qualifica-tion at the time of validation are routinely verified and recorded. in that way the un-changing quality of the process can be guaranteed. the frequency and scope of routine checks must be defined by the op-erator since the conditions prevailing in each Central Sterile Supply department (CSSd) will differ. the final decision on routine checks is taken by the user, who then must answer to the supervisory bod-ies.it was necessary to take a look at all the (operating) media used in the cleaning and disinfection process in order to be able to formulate a good and robust in-house standard.Besides, the performance of different test systems was compared with that of one of the test instruments specified in diN eN iSo 15883-5. that comparison helped to reach a decision on which test system should be used to assure optimum routine monitoring.A standard on test soil would be benefi-cial as its use would be binding for the manufacturers, too, and the use of just any test systems chosen by the manufacturer would be a thing of the past.the activities described in this article led to the introduction of the in-house standard for routine checks of Wds at or-thopädie Bad hersfeld.

|| Introduction Standard diN eN iSo 15883-1 unequivo-cally states that routine tests must be car-ried out and recorded. it is not enough to repeat performance qualification (revali-

cleaning arms). this can reduce the costs incurred for routine tests and should be borne in mind when purchasing a new Wd.the German Society of Sterile Supply (dGSV), in particular its Quality task Group, also publishes recommendations on routine checks. these, too, are based on diN eN iSo 15883 and are a valua-ble guide to compilation of an in-house standard.

|| Routine checks needed Demineralised water quality and tap water qualityWater, as a medium, plays a pivotal role in the cleaning process conducted in a Wd. for that reason, this too must be routinely tested. the use of demineralised water for the entire cleaning and disinfection proc-ess offers many advantages, e. g. a con-stant ph value in the mildly alkaline range.

dation) on an annual basis, because one cannot guarantee that cleaning and dis-infection in a Wd will not have changed over the course or a year. Changes to the water quality, demineralised water qual-ity or to the chemical substances cannot be ruled out.Annex A, table A.1, of diN eN iSo 15883-1 explains which processes should be checked on a routine basis, and how often testing should be performed. this table is very detailed and by no means self-ex-planatory. therefore it can only serve as a guide to compiling one's own standard for routine testing.Since the design and fittings of a Wd play an important role in routine activities, de-tails of routine testing are given in the vali-dation report. for the Wds in our estab-lishment these details were confined to annual servicing (to be carried out by a service engineer) and six-monthly check of the cleaning pressure. But a six-month-ly check is by no means enough to dem-onstrate the repeatability of a validated process.the manufacturer’s instructions contain information and data on the fittings re-quired in the Wd. one must ensure that only a Wd that complies with the pertinent standards is used.the greater the number of processes moni-tored by a Wd itself, the fewer the checks that need to be carried out by the user. the Wd takes charge of many monitoring tasks as a routine measure, e.g. of the tempera-ture-time course for the cleaning and dis-infection step (A0 value), dosage quantity of process chemicals and amount of water used for each process step. more checks are performed by new Wd models (e. g. monitoring of the rotational speed of the

330_335_Blechschmidt_en_ZT_5_12.indd 330 22.10.12 23:26

Key Words

from the field | 331Central Service 5/2012

(e. g. suspected poor cleaning), but at least once weekly. it is important that this task be assigned to well-trained personnel who have the necessary expertise.While the test, used for validation, has a lower detection level of 1 µg protein, it is suitable only to an extent for everyday practice because it is very comprehensive and complex. therefore the rapid biuret protein test is used to check for any protein residues. this produces an evaluable result within 10 min. Such tests are available with dif-ferent detection limits. in the establish-ment described here, we used a rapid test with a detection limit of 15 µg protein.the cleaning batch, data and instrument must definitely be recorded in the final documentation.

Loggers for monitoring A0 value and clean-

ing pressure A logger system must be used to provide for monitoring of the A0 value independ-ently of the Wd. however, the A0 value is monitored by the Wd itself in the case of Wds that conform to the pertinent stand-ards, hence routine control is not needed.this will, nonetheless, be elaborated on here, i. e. in the context of monitoring the cleaning pressure. the cleaning pressure is vital for good cleaning. the rotational speed of the cleaning arms is determined by the cleaning pressure, and that speed is needed to assure adequate flushing of instrument lumens.

rine-induced pitting corrosion prevented. dosage mistakes can result in poorer cleaning and, as such, successful decon-tamination is not assured. Besides the risk of chlorine-induced pitting corrosion at a ph value of 10.5 is very high, hence the likelihood of damage to the instruments and Wd must be borne in mind. for that reason the filling level of chemical substances must be checked daily before placing the Wd in operation.

Checking mechanical fitting daily, before running the first Wd process, the cleaning arms and all luer lock tube connections, wheels, pump sump and filter sieves are inspected. the loading trolleys are also checked on the docking systems in the Wd (seals intact?).the inside of the Wd is also visually in-spected for cleanliness or deposits (rust, silicates) and the door seals are also checked.Next visual inspection of the outside of the Wd is performed to detect any dam-age or leaks.routine checks of problem instrumentsour institution reprocesses orthopaedic instruments. these are very complex, have several joints and can only be partially dismantled. to ensure that these instru-ments, too, are free of residual soils and protein residues, they must definitely be used to simulate a worst-case load at the time of validation.As a routine measure these instruments are subjected to spot checks as needed

this assures a good cleaning result as well as good protection against chlorine-in-duced pitting corrosion.demineralised water is produced in large quantities in advance, so microbiologi-cal testing should be performed at cer-tain intervals. if the demineralised water is greatly contaminated with microorgan-isms (e. g. Pseudomonasaeruginosa, a bac-terium typically found in the nasal region) there is a risk of disintegration residues being deposited on the instruments after the Wd disinfection process, for example in the form of pyrogenic substances.Chemical testing of the demineralised wa-ter quality is also needed. A daily check of the conductivity value and of the ph value is needed, as the ph value of the chemical detergents may have changed. this would adversely impact on the standard of instru-ment cleaning. furthermore, residues can persist on the instruments, leading to dis-colorations on these after the sterilization process (e. g. silicates). for tap water, quality analysis of the water supply system on an annual basis is suffi-cient since in general tap water is used in the cleaning process only for a cold pre-rinse.

Chemical detergents Chemical substances are used in the cleaning process to increase the ph value (depending on the chemical substance) such that optimum cleaning results can be achieved for the instruments and chlo-

Table 1: Description of indicators used

Indicator Chemical cleaning indicator (gke) TOSI PCD (BAG) Simicon PCD (Simicon)

Design

test kit with indicators with four different levels of difficulty (1 – easiest to 4 – most difficult); clip for mounting indicator on tray

stainless steel disc with blood test soil

stainless steel disc (V4A steel) with a blood test soil and additives as per eN iSo 15883-5

PCD

No; response to cleaning shown by highest difficulty level was chemi-cally altered to make it similar to that exhibited by a PCd

yes; a lid is fitted to the disc with a gap width varying from 2 – 3mm to around 4 mm

yes; small stainless steel box with several holes

Mounting

mounted with a clip on the tray, preferably directly beneath the spray arms and in the corners of the loading trolley (known to be vulne-rable locations in the Wd)

placed lying down or standing up and secured to the trays

indicator is inserted into a PCd; PCds are distributed in the Wd beneath the spray arms and at the corners of the trolley

Evaluationevaluation table provided by manu-facturer

evaluation table provided by manu-facturer

evaluation table provided by manu-facturer

Checking the flushing perfor-mance

flow PCd available; fitted with the same indicators and connected to a flushing port in the Wd

flushing indicator (toSi-lumCheck) available

flow PCd available; fitted with the same discs and connected to a flushing port in the Wd



for that reason an experiment was car-ried out on the spray apparatus in a test laboratory. this apparatus simulates the spray activity of a Wd, enabling accurate setting of the flow rate, temperature, dos-age of chemicals, and thus producing re-producible results. Since in our establishment we intend changing the chemical detergents, i con-ducted the experiment with different de-tergents. As such, the experiences gleaned can be used in the selection process. to test how the indicator responds to mis-takes/malfunctions, a test series was also run without chemical detergents, using only demineralised water. it is imperative that mistakes be signalled during routine checks.

Fixed variables used in the experiment the following fixed variables were used for the experiment:

– Temperature: 55 °C (optimum clean-ing temperature as stated by the deter-gent manufacturers Bode Chemie and dr. Weigert)

– Flow rate: 0.5 l/min (the flow rate used in a normal Wd in our establishment is

this visual inspection and checking of the A0 value are of paramount importance for batch release after a successful process outcome. if there are still residual soils on the instruments, this can point to a faulty cleaning process, resulting in failure to re-lease the respective batch. this batch must be recleaned and visually inspected again.

|| Materials and experimental procedure

Description of a choice of test systemsthe indicators described in table 1 were used in a series of tests.

Test series on spray apparatus – conditions and preparationto demonstrate the differences between various indicator systems, one must take a close look at the behaviour exhibited by the indicator in the cleaning process. this is hardly possible in a normal Wd. Nor is re-producibility of the tests guaranteed since minor changes can always be observed in the Wd (e. g. fluctuations in the cleaning pressure, etc.).

While based on the validation report of the establishment described here, the clean-ing pressure need only be monitored once every six months, i believe that this must be done much more frequently. i deem a monthly routine check of the cleaning pressure to be advisable and adequate.to that effect a logger system that con-currently checks the A0 value and clean-ing pressure is used. this system is easy to programme and use. once successfully programmed it is fitted to a luer lock con-nected in the Wd and placed in the tray. the logger is read on successful comple-tion of the process and evaluated using the software supplied.A logger system confers many benefits even if there are problems with the Wd, e. g. poor cleaning results.

Visual inspection of instruments for residu-al soils and deposits Probably the most important routine check is visual inspection of instruments for re-sidual soils and deposits. this check is done using a magnifying lamp in order to be able to detect even the most minute soils, deposits or pitting corrosion.

Temperature 55°C, Flow Rate 0.5L/min Dismoclean Twin System Test Series Demineralised Water

Test soil completely removed


Indicator as per EN ISO 15883-5 (sheep blood)

Test soil very slightly visibleProtein detection:

negative


Protein detection:negative


pH value ≈ 10.7Dosage:

3 ml/L Basic2 ml/L Zym













Remarks

Optimum resultProtein detection:

negative

Test soil slightly visible

Protein detection: positive


Protein detection: negative

Optimum result, also with standing

complete PCD


1 minute

3 minutes

5 minutes

10 minutes

Optimum resultTest soil

completely removed


completely removed

gke blue gke redTime window BAG indicator SIMICON

30 secondsOptimum result


gke yellow gke green

Table 2: Test series 1 (detergent: Dismoclean Twin)

Time window



ties. the discs, to which the test soil had been applied, were conditioned overnight at 30 °C and at a relative ambient humidity of 45 % and then stored in sealed dishes until just before being placed in the spray apparatus.

Conduct of test series After preparation of the indicators and spray apparatus (selection and dosage of chemical detergents, demineralised water kept in stock), testing was initiat-ed by selecting the programme. first, the detergent dismoclean twin (manufac-turer: Bode Chemie, hamburg) and the 10-minute programme were selected, test-ing all indicators with that programme. Next came the 5-minute, 3-minute, 1-minute and the 30-second programme, using indicators in each case. the results were evaluated immediately on the basis of the evaluation sheets sup-plied by the indicator manufacturers. the terms specified in the evaluation sheets were used in order to achieve reproduc-ible results. the gke indicators were stuck on a docu-mentation sheet specially designed to that

– Time: different time windows for re-cording the cleaning performance 30 seconds, 1, 3, 5 and 10 minutes.

– Indicators: BAG, Simicon, gke yellow (level 1), gke green (level 2), gke blue (level 3), gke red (level 4), sheep blood indicator.

Preparation of indicators the PCd from the firms BAG and Simicon are vacuum packed and have been stored under optimum conditions of between 2 °C and 25 °C in sealed protective foil, where they were also protected against expo-sure to disinfectant and chemical vapours. the expiry dates were observed: 18 months as from the date of manufacture. they were unpacked and used only imme-diately before they were inserted into the spray apparatus. the cleaning indicators from the manu-facturer gke were packed in a foil pouch and were also stored under optimum con-ditions. Preparation of the sheep blood indicators was outsourced to a company since i did not have the necessary conditioning facili-

3.5 l/min. the lower rate was selected so that the rinse process would not un-fold too rapidly, and differences could be identified more easily)

– Demineralised water in the entire proc-ess (only then is the exact ph value spec-ified in the manufacturer’s instructions reached)

Changeable variables in the experiment the changeable variables in the experi-ment were:

– Chemical detergents: dismoclean twin System (manufacturer: Bode Chemie) is a two-component system consisting of an alkaline and an enzymatic deter-gent; ph value with demineralised water 3 ml/l: approx. 10.7.Neodisher mediclean forte is a single-component system with alkaline and enzymatic components; ph value with demineralised water 2 – 10 ml/l: 10.5 – 11.0. Neutralization can be omitted in the process for both detergents since their components are gentle on materials (cost savings).

Temperature 55°C, Flow rate 0.5L/min Neodisher mediclean Forte Test Series Demineralised Water

Time window BAG indicator SIMICON



gke yellow gke green gke blue gke red

1 minute

3 minutes

5 minutes

10 minutes

Remarks

Optimum resultProtein detection:

negative

Test soil completely visibleProtein detection:

positive

Test soil largely visible


Optimum result, also with standing

complete PCD



completely removed


completely removed

pH value ≈ 10.5Dosage: 5 ml/L pH value ≈ 10.5

Dosage: 5 ml/LpH value ≈ 10.5Dosage: 5 ml/L

pH value ≈ 10.5Dosage: 5 ml/L







Test soil slightly visibleProtein detection:

positive




Table 3: Test series 2 (detergent: Neodisher Mediclean Forte)



3 of the gke indicators, and in level 4 no rinse reaction could still be observed. only after 10 min was level 3 completely, and level 4, partially, removed. that result is also suggestive of a good cleaning performance in the process since blood and protein residues were complete-ly removed. that the gke indicator (diffi-culty level 4) was not completely cleaned attests to a level of difficulty encountered when cleaning that that indicator. While gke indicators were not placed in a PCd in the process, the cleaning response was similar to that evinced by an indicator that had been placed in a PCd. test series 3 (demineralised water; table 3) produced surprising results. All indica-tors with blood soils had been completely cleaned off in a short time, the BAG was clean after 30 seconds, Simicon after 3 min and the sheep blood indicator after 1 min. the protein tests were negative. only in the case of the gke indicators was the col-our completely removed after 10 min in difficulty level 1, level 2 was partially removed but no cleaning reaction could be observed for level 3 and 4.

30-second programme, followed by Simi-con in the 3-minute and then the sheep blood indicator in the 1-minute pro-gramme. the gke indicators (all levels of difficulty) were run in the 10-minute pro-gramme. the results were evaluated and recorded as described above.

|| Evaluations and results of the test series

on using dismoclean twin (test series 1; table 1) optimum results were achieved already after the 3-minute for the test soils of all indicators used. the test soils used in all indicators were removed without any residues. the protein tests were also neg-ative. this was a very good result since it attest-ed to a very good cleaning performance in the process. on using Neodisher mediclean forte (test series 2; table 2) after 3 min the test soils from BAG, Simicon as well as the dena-tured sheep blood indicator were com-pletely removed. the protein tests were also negative. however, colour residues could still be detected for difficulty level

effect. the results obtained for the other indicators were entered in writing on this sheet (tables 1 and 2). to provide for good and conclusive evalu-ation, the indicators were checked after each programme not only for visible soils but were also subjected to the rapid biuret protein test (this was possible only for the BAG, Simicon and sheep blood indicator). A rapid protein test with a detection limit of 15 µg protein, which is also used in our institution, was selected. results were also recorded in writing, with additional pho-tographic documentation. on completion of the first test series, the spray apparatus was rinsed (to prevent en-trainment of the previous chemical deter-gent) and then used for the next detergent. the second test series was run with Neod-isher mediclean forte (dr. Weigert, ham-burg), using the same procedure as for the first test series. the results were evaluated and recorded as described above. Next came the third test series with dem-ineralised water. here, too, the appara-tus was rinsed first of all. testing was launched with the BAG indicator in the

Temperature 55°C, Flow Rate 0.5L/min Test Series with Only Demineralised Water; No Chem. Detergents Demineralised Water

gke blue gke redTime window BAG indicator SIMICON



gke yellow gke green

1 minute

3 minutes

5 minutes

10 minutes

Remarks



Only demineralised

water

Only demineralised

water Only demineralised





water


Complete removalProtein detection: negative

Table 4: Test series 3 (demineralised water)



Checks to be carried out once every year:

– test municipal water quality: request values from water supplier

– Competent party: engineering depart-ment

– Servicing and inspection of Wd, sensor calibration, revalidation

– Competent party: Customer Service and CSSd management

the standard described above is not valid for general use. rather, it has been com-piled for application in our establishment. one often hears the view expressed that routine monitoring can be completely dispensed with so long as standards and guidelines do not stipulate anything to the contrary. this is a misunderstanding and such a view amounts to an erroneous per-ception. What is correct is that – as pointed out in the introduction – routine monitor-ing is absolutely required, but its nature and scope have not yet been specified therefore to date there is, unfortunate-ly, no other solution other than for each establishment to devise a routine moni-toring regimen for its own reprocessing activities, while justifying this and then imposing it as an in-house standard. this is the only way to guarantee that the proc-ess quality verified at the time of validation is maintained in everyday operations and that any changes will not go unnoticed. ■

|| References1. diN eN iSo 15883-1 Washer-disinfectors

– Part 1: General requirements, terms and efinitions and tests (iSo 15883-1:2006); S. 41.

2. eN iSo 15883-1:2009 Washer-disinfectors – Part 1: General requirements, terms and definitions and tests (iSo 15883-1:2006) German version eN iSo 15883-1:2009

3. Weinig, f., hahnen, K. (hrsg.): handbuch Sterilisation. lehr- und lernbuch für die fachkundelehrgänge i und ii von dGSV und SGSV. 4. Auflage. 2003.

are not blocked, docking system intact; check wheels and luer lock connections

– Check pump sump

– Check filter sieves

– Visual inspection of detergent storage containers

– Competent parties: specialist person-nel in CSSd (i. e. who have acquired the requisite expertise by successful com-pletion of the relevant training courses, levels i, ii and iii)

Checking after completion of each batch in the Wd:

– Visual inspection of instruments for re-sidual soils and deposits, with the aid of a magnifying lamp

– Check the A0 value on the basis of the Wd batch release data in the batch doc-umentation software

– Competent parties: specialist personnel in CSSd (as described above)

Checks to be carried out once weekly:

– Checking problem instruments by means of the biuret protein test, eval-uate using the manufacturer's evalua-tion sheet

– Competent parties: specialist personnel in CSSd (as described above)

Checks to be carried out once every 4 weeks:

– Check the spray pattern with gke level-4 cleaning indicators. distribute the indi-cators beneath the spray arms and at the corners of the loading trolley, using at least five indicators per batch. record results on evaluation sheets available in the CSSd

– Competent personnel: shift manag-er (successful completion of training courses, levels ii and iii)

– Check the cleaning pressure and A0 val-ue with a logger system, documentation via logger system software

– Competent personnel: shift manag-er (successful completion of training courses, levels ii and iii)

Checks to be carried out once every six months:

– microbiological testing of the deminer-alised water

– Competent personnel: infection control team/microbiologist and test laboratory

– Chemical testing of demineralised water

– Competent personnel: infection control team/microbiologist and test laboratory

these results show that only the gke indi-cators pointed to deviations in the clean-ing process, since a particular ph value was needed in order for these indicators to be cleaned off. As regards the in-house standard it is im-portant to know:

– Which indicators are used for routine checks in a Wd. do these detect faults in the process?

– Which chemical detergents are chosen prior to validation so that optimum re-sults can be achieved in the process?

in practice the appearance of instruments after a successful cleaning process is, of course, important. do they still perhaps harbour protein residues? the following results were obtained from these series of tests for the in-house standard.

1. for reprocessing in the Wd, municipal water is used only for the cold prelimi-nary rinse phase, with demineralised water being used for all subsequent process steps. only on using deminer-alised water can a ph value be main-tained for the process, as specified in the manufacturer’s instructions.

2. for the routine checks of the Wd gke indicators are chosen, using the level 4 indicator with a clip for the trays as well as the flow PCd. these give the added sense of security that malfunctioning of the cleaning process will be signalled.

3. the chemical detergent to be used in future is dismoclean twin System from the manufacturer Bode. Above average cleaning results can be expected with this detergent. these insights will be taken account at the time of Wd revali-dation.

|| Content of an in-house stand-ard for routine checks in a WD

the outcome of all these endeavours is the final standard for routine checks in a Wd. this is broken down into the follow-ing periods of time: daily, weekly, 4-week-ly, 6-monthly and annual routine checks.

Standard for routine checks in a WD for in-house quality assurance Checks to be carried out once daily, before placing the Wd in operation for the day:

– Visual inspection of the Wd, including on the inside, for any damage or deposits

– Check the loading trolley, cleaning arms for unimpeded movement, that nozzles


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