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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
0
5
10
15
20
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
0
5
10
15
20
25
30
19
94
19
95
19
96
19
97
19
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19
99
20
00
20
01
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20
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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
0
5
10
15
20
25
30
35
40
45
50
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
0,0
5,0
10,0
15,0
20,0
25,0
30,0
35,0
40,0
45,0
50,0
55,0
60,0
65,0
70,0
ug protein Instrument side
Instrument number
Results ProReveal assay for protein levels from all instruments.
N= 187 instruments
0
200
400
600
800
1000
1200
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