Improving the cleaning of surgical instruments – the importance of pre-treatment and performance qualification testing

Professor Andrew Smith

Disclosures

Funding to attend WFHSS from

Study funded by Scottish Infection Research Network

https://www.gla.ac.uk/research/az/sirn/

Plan 1. Defining clean 2. vCJD update in UK 3. Role of wetting agents 4. Improvement from what baseline ? 5. Laboratory studies 6. Clinical trial of wetting agents 7. Conclusions

Improving the cleaning of surgical instruments…..

"Those who cannot learn from history are doomed to repeat it."

George Santayana

"We learn from history that we learn nothing from history."

George Bernard Shaw

1. Defining clean

3.9 Cleaning: removal of contamination from an item to the

extent necessary for its further processing and its intended

subsequent use (BS EN ISO 15883-1:2006)

4.2.1.1 Cleaning shall be deemed to have been achieved

if the acceptance criteria for the test method in

6.10 and the relevant subsequent parts of ISO 15883 have

been met.

The test method for type testing and operational testing

(6.10.2) shall employ one of the nationally published

tests soils and methods as described in ISO/TS 15883-5

1. Defining clean

The test method for PERFORMANCE QUALIFICATION

of cleaning efficacy is described in 6.10.3 and shall include

the use of one of the methods for the detection

and assessment of residual proteinaceous contamination

given in Annex C.

3.43 Performance qualification:

process of obtaining and documenting evidence that the

equipment, as installed and operated in accordance

with operational procedures, CONSISTENTLY performs in

accordance with predetermined criteria and thereby

yields product meeting its specification

1. Defining clean

Annex C protein residue tests are not equal

are not equally sensitive.

C.1 Ninhydrin & Biuret method (C.3) similar sensitivities but are

regarded as a limit test and a semi-quantitative test

respectively.

1. Defining clean

The OPA method (C.2)

More sensitive

Requires use of laboratory facilities.

Both ninhydrin and OPA methods

react with α- and ε-amino groups

of proteins.

1. Defining clean

C.2.4 Acceptance criteria

When tested in accordance with C.2.3, the extinction value shall

be < 0,020.

Corresponds to 200ug protein/instrument

Why worry about protein ?

BSE & vCJD history Background to measures to improve cleaning

2. vCJD update in UK

vCJD epidemiology

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25

30

19941996199820002002 2004 2006 2008 2010 2012 2014 2016

vCJD

Total vCJD deaths Aug 2017 = 178

MM MV VV

Normal 39% 50% 11%

sCJD 71 13 16

vCJD 100 * 0

* = x2 asymptomatic cases

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94

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vCJD

Total vCJD deaths Aug 2017 = 178

Appendix I study: Taken out 1995-99 (3/12,674 +ve)

Appendix II study: Taken out 2000-2012 (16/32,441 +ve)

Appendix III study: Taken out pre-1980 (2/14,692 +ve)

Appendix III study: Taken out pts born after 1996 (5/14,824 +ve)

0

5

10

15

20

25

30

199419961998200020022004200620082010201220142016

vCJD sCJD

Appendix I study: approx 1:4,000

Appendix II study: approx 1:2,000

Appendix III study: approx 1:4,200

Take home message: Continue precautionary

approach

Advisory Committee on

Dangerous Pathogens

(ACDP)

…..that there should be ≤5 μg of protein in situ

on the side of any instrument tested….

Timescale: Neurosurgery by 1st July 2017

Other instruments (acute sector) by 1st July 2018

2. vCJD update in UK

3. Role of wetting agents

1960 2nd Ed:

“Instruments must be cleaned as soon

as possible after use, to avoid rusting

or pitting, and to remove soil before it

can dry and harden in the serrations

and crevices. “

3. Role of wetting agents

Lipscomb et al. Effect of drying time, ambient temperature and

pre-soaks …......... J Hosp Inf 2007; 65: 72-77.

Secker et al. Adsorption of prion and tissue proteins…..

following dry and wet storage conditions.

J Hosp Inf 2011; 78: 251-255.

Secker et al Efficacy of humidity retention bags …..improved

cleaning of tissue proteins …....to surgical stainless steel surfaces.

Biofouling 2015; 31: 535-541.

4. Improvement from what baseline ?

Measurement based on compliance with technical requirements

Equipment,

Facilities,

Staff,

Management.

Murdoch et al JHI 2006 432-438

Residual protein on range of instruments

One hospital 0.62 – 3.5 mg

Max residual protein = 45mg on one instrument!

2006 – Sterile service Departments

5. Laboratory studies

Oral Presentation at WFHSS 2017

by Dr Sandra Winter

6. Clinical trial of wetting agents Study funded by the

Scottish Infection Research Network

Reducing the risk of vCJD by improving the cleaning

of neurosurgical instruments

Post Doc Scientists: Tim Tomkinson, Meg Pajak & Sandra Winter

Co-investigators include;

David Lappin & Andrea Sherriff

Ian McIvor (Cowlairs SSD, NHS GG&C),

Pamela Philp (Senior Charge Nurse, QEUH, NHS GG&C),

Nigel Suttner (Consultant Neurosurgeon, QEUH, NHS GG&C),

Alan Stewart (Cowlairs SSD, NHS GG&C).

Sulisti Holmes Health Facilities Scotland, NHS National Services)

6. Clinical trial of wetting agents

Project aims

a. Which neurosurgical instruments are the most difficult to clean

prior to steam sterilization?

b. Which pre-cleaning treatment methods are most efficacious

and cost-effective at improving the cleaning of neurosurgical

instruments under operational conditions?

c. Can a quantitative residual protein assay quality control

programme be used to quality assure the cleaning of

neurosurgical instruments?

6. Clinical trial of wetting agents The sites

QEUH Neurosurgical theatres

Cowlairs,

Sterile Service Department 324,553 trays per annum

6. Clinical trial of wetting agents The neurosurgical instrument sets

Craniotomy set

Bard-Parker handle

6. Clinical trial of wetting agents

Instruments assayed from Craniotomy set

Blunt elevator

Sharp elevator

Toothed forceps

Bayonet forceps

Swedish/McDonalds

Dissector

Adsons Dural

forceps

McKissock

Dural scissors

The washer, wash cycle and detergent AWD: Getinge CM310

Detergent: Metal Clean 5%

(1-2% NaOH solution)

pH 13.1

6. Clinical trial of wetting agents Protein assay – ISO 15886 method

C.2.3…...5ml of 1% SDS 30 mins

This study = 10ml of 1% SDS 30 mins

To ensure more efficient coverage

of instrument

Disadvantage: LOD 30ug/Instrument

6. Clinical trial of wetting agents

Arm 1: Sets returned from theatre in plastic bag

Arm 2: Commercial “wetting agent” foam applied & sets

contained in plastic bag

Arm 3: Wound pad soaked in sterile water & sets

contained in plastic bag

N= 10 sets for each arm

Each set tested 8 instruments

6. Clinical trial of wetting agents

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BP handle Sharp el Blunt el toothedforc

baynotforc

dissector Adsons McKissok

Com Wet Sterile H20 No wet

Note: Limit of detection 30ug/instrument

Commercial wetting agent or sterile water equivalent efficacy

Both (p<0.0001) significantly better than no water agent

Protein ug/

instrument

Difficult to clean ? & Quality Control ?

G- Box (Pro-reveal) methodology

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ug protein Instrument side

Instrument number

Results ProReveal assay for protein levels from all instruments.

N= 187 instruments

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0 1 2 3 4 5 6 7 8 9 101112131415161718192021222324

Pro

tein

s p

er

instr

um

en

t (µ

g)

Instrument

G-box – cleaned instruments

Wholeinstrument

Cleaned Instruments 22-

24s Instrument name

G-Box value

(ug/instrument)

(n=1)

22 Periosteal elevators 51

22 ‘’ 483

23 ‘’ 45

23 ‘’ 206

24 ‘’ 12

24 ‘’ 163

Quality Control ? Loading pattern of instruments

Difficult to clean ? No obvious pattern

0,05,0

10,015,020,025,030,035,040,045,050,055,060,065,070,0

Craniotomy tray ready for loading into automated washer disinfector

Loading pattern of test instruments into washer basket as part of PQ test, addition of Edinburgh test soil and BEFORE wash process

Loading pattern of test instruments into washer basket as part of PQ test, addition of Edinburgh test soil and AFTER wash process

7. Conclusions

2. A proprietary plastic bag, absorbent pad & sterile water are

equivalent to commercial wetting systems.

1. “Wetting systems” after use improve cleaning efficacy

Costs if implemented a commercial wetting agent =233,308 Euro

Assume N= 324,553 trays per annum

Costs if implemented a pad & sterile water = 176,081 Euro (25%)

Costs if implemented a liner & tap water = 26,412 Euro (89%)

7. Conclusions

3. Systematic PQ testing is essential in establishing

operating parameters.

4. The loading pattern established at PQ MUST be repeated

for each load

"Those who cannot learn from history are doomed to repeat it."

George Santayana

"We learn from history that we learn nothing from history."

George Bernard Shaw