The Principles of Medical Device Decontamination

Compiled by the D econtamination P rofessional E xpert C ommunication F orum

The Decontamination Professional Experts Communications Forum (DPECF) gratefully acknowledges the generous support of the following professional bodies, without whose support this publication would not have been possible, both in terms of their representatives contributing to the content development, and their financial support for its production. Their commitment to advancing the education, collaboration and innovation in the Decontamination of Reusable Medical Devices field has been invaluable to the realisation of this document.

Foreword It has been acknowledged for some time that there is no single source of information providing an overview of medical device decontamination. There are many standards and guidance documents which describe a variety of decontamination processes and the operation and testing requirements of related equipment, but no single document that provides an introduction to the principles of medical device decontamination. The Microbiological Advisory Committee (MAC) published a document containing similar information many years ago which was archived. As a consequence of this void, a subgroup of the Decontamination Professional Experts Communication Forum (DPECF) was established, to produce a document containing an introduction to the principles of medical device decontamination; effectively a single source of information for those in healthcare wishing to gain an appreciation of this subject, and to guide the practitioner to further reading. This document is not intended to duplicate or replace the many detailed publications it cites and from which it draws information. The intention of developing the content is to provide basic information on the principles of reusable medical device decontamination. The content has been developed by a small group of people representing their professional bodies, identified in the acknowledgments below, and other expert contributors in the field of decontamination. The content of this document does not necessarily represent the views of the professional bodies who have supported its production. It is the intention to publish an electronic version only at this time, which will be hosted on the Central Sterilising Club website, with links to this from other professional body websites, thereby having only one master copy making version control easier. The approach to presenting the content has been to keep text to a minimum, using images, pictures, tables, algorithms and flow charts to support easy reading and referencing.

Foreword Medical device innovations are also included, together with suggestions on how to undertake an investigation where decontamination failure is suspected. It is intended to include questions to support determining root cause for decontamination problems, failures or identified risks. Acknowledgements Thank you to the following DPECF subgroup members and chapter authors:

Val O’Brien

CSC, Group Chair, past CSC Chair 2017-2020

John Prendergast

Principal AE(D) NWSSP, CSC Chair 2024 to date

Dr Brian Kirk

AE(D), IHEEM

Director of Research and Emerging Technologies, IDSc Healthcare Infection Society (HIS) past Chair 2001 to 2007

Darren Carter

Dr Robert Spencer

Dr Mike Simmons

Consultant Medical Microbiologist (Wales)

Past Chair of AE(D) Registration Board, IHEEM, (Sadly departed) Consultant Nurse for HCAI (Wales) Representing the Infection Prevention Society Semi-Retired Nurse practitioner, Advanced Clinical Endoscopist

Graham Stanton

Gail Lusardi

Helen Griffiths

Helen Campbell

Director of Education, IDSc

Victoria Daniel

Infection Control Scientist (Wales)

Retired UK Health Security Agency Consultant Clinical Scientist

Dr Peter Hoffman

Richard Bancroft

Chair ISO/TC 198

Retired UK Health Security Agency Scientific Lead in water microbiology

Dr Jimmy Walker

Dr Karina Jones

AE(W), IHEEM

Mett Smart

Past Research Director, IDSc 2018 to 2022

This document has been prepared in the United Kingdom and primarily follows British English spelling conventions. However, certain chapters reflect the author’s preference for American English in specific terms such as ‘sterilise’, ‘steriliser’, and ‘sterilisation’, which have been amended accordingly to use the ‘z’ spelling. As many of the referenced standards are influenced by American English, their original spellings have been retained.

CONTENTS

Page Chapter Title

Author

1-3

Foreword

Val O’Brien

3-4

Contents

5-17

Chapter 1 Microbiology

Mike Simmons

18-31

Chapter 2

Decontamination Life Cycle

Val O’Brien

Managing Reusable Medical Devices and Green issues Minimal Invasive Surgery and Complex instrumentation Legislation, Standards and Guidance Decontamination Water Requirements Reusable Flexible Endoscopes and accessories

32-47

Chapter 3

Val O’Brien

Darren Carter Mett Smart

48-55

Chapter 4

56-61

Chapter 5

Richard Bancroft

62-75

Chapter 6

Jimmy Walker

76-85

Chapter 7

Helen Griffiths

86-91

Chapter 8 Detergents

Richard Bancroft

92-97

Chapter 9 Disinfectants for Medical Devices

Richard Bancroft

Sterilization Processes for Medical Devices

98-117

Chapter 10

Brian Kirk

118-129 Chapter 11 Monitoring Sterilization Processes

Brian Kirk

CONTENTS

Page Chapter Title

Author

Infection Prevention and Control, including Environmental cleanliness and Occupational Health and Wellbeing Training, Education and Staff Competency

Gail Lusardi Victoria Daniel

130-147 Chapter 12

Helen Campbell John Prendergast

148-162 Chapter 13

Approach to analysing perceived decontamination failures

163-169 Chapter 14

Peter Hoffman

170-180 Glossary

Medical Device Decontamination

Microbiology

Micro-organisms pervade all parts of our world, including very harsh environments but for decontamination, we are interested in those that live within the environments we occupy, the food and water we ingest and within and on our bodies as well as the bodies of animals we may contact. The human body is home to a staggering number of microorganisms living in us and on us; around 8 trillion more organisms than human cells in the body 1-3 . These include recognised potential pathogens, organisms that are commonly associated with infection as well as organisms that are normally considered harmless. The latter are considered normal flora but even these can be associated with ill-health. What is becoming very evident is that good health is associated with a well-balanced microbiome, a more recently adopted term for normal flora. A foetus in-utero is normally free of any organisms and begins to acquire them from the moment their mother’s uterine sac is breached and they begin their journey down the birth canal or delivery by Caesarean section. The bulk of our normal microbiome is gut-associated and as any new parent discovers, in the initial period of their child’s life the yellow, sweet-smelling faeces is very different to their own. This is related to the initial milk-based feed which the baby has for the first few months of life before being weaned, when the faeces gradually become darker and more like their parents 4 . What this illustrates is how in health, each of us lives in harmony with our microbiota, and the microbiota is subject to change over time as a result of our lifestyles and health status. As noted, the organisms include some that are considered pathogenic. However, in a diseased state, a person who has a disrupted microbiota and may be immunocompromised, can become infected with organisms that are normally considered non-pathogenic. Most infections will be derived from our own microbiota and when associated with interventional procedures, breach the first line of our immune defences.

This essentially relates to breach of skin and mucous membranes by the procedure, allowing the microbiota access to deeper tissues and may lead to infection. Only if the decontamination process has failed to remove microorganisms are they capable of direct transmission to exposed tissues and establish infection.

What are microorganisms?

The simplest way to look at this is to understand the micro element of microorganisms. Micro is derived from both New Latin micro- (“small”) and from Ancient Greek μικρός (mikrós, “small”) 5 and therefore means a small organism, which can normally be studied via a micro-scope. Similarly, this chapter on micro-biology is the study of organisms that are of a small biology.

Clinical microbiology also includes organisms that can be seen without the microscope e.g. worms, insect parasites e.g. fleas and lice but these are more complex organisms. Many are smaller or are detected by finding their eggs using the microscope.

All organisms are classified as either Eucaryote or Procaryote 6 , which are defined at the cellular level. A eucaryote is the more complex organism and the essential difference between a eucaryote and procaryote is the presence of the replicating DNA being bound within a nuclear membrane. Eucaryotes range from the very large giant sequoia trees and blue whales to single celled organisms. By contrast procaryotes are always single celled and lack any internal compartmentalisation.

The decontamination scientist is seeking to make a medical device safe, which requires the inactivation or removal of potentially harmful agents capable of initiating disease including infecting microorganisms.

i Not strictly true, there are bacteria that live in extreme conditions (not known to be human pathogens or even opportunistic pathogens), which do have partitions in their structures 7 .

These can range from the more complex to the simplest forms and can be grouped as in Table 1.1 below.

Organism Group

Eucaryote / Procaryote

Infection Examples

Worms (e.g. pinworm) and ectoparasites (e.g. scabies) may be visible to the naked eye but others (e.g. filarial worms) are microscopic as are the ova and cysts of larger organisms in these groups (e.g. tape worm ova) Gut associated infections (e.g. giardiasis, cryptosporidiosis, amoebiasis), blood borne (e.g. malaria, babesiosis) and deep seated infection as in toxoplasmosis, which can infect eye, lymph nodes and brain Superficial infections – dermatophytes (ringworm), nail infections – vaginal thrush (candidiasis) to more serious disease – disseminated fungal infection, respiratory aspergillosis. Community acquired e.g. impetigo (streptococcal), boils (staphylococcal), gastrointestinal (salmonellosis) to healthcare associated e.g. surgical site infections (staphylococcal, streptococcal), intra- abdominal (mixed infections with Gram negative, positive and anaerobic bacteria)

Parasites

Eucaryote

Protozoa

Eucaryote

Fungi

Eucaryote

Bacteria

Procaryote

Ova of Schistosoma mansoni (Wet mount)

Oocysts of Cryptosporidium spp. from faeces (ZN stain)

Streptococci (Gram-positive cocci in chains) seen in Gram stain from a positive blood culture.)

Fusobacterium necrophorum (Gram- negative bacillus) from a throat swab culture Gram stain

Organism Group

Eucaryote / Procaryote

Infection Examples

Classified according to shape, presence of envelope and type of nucleic acid i.e. DNA or RNA, single or double stranded. Examples include: » childhood rashes e.g. measles, slapped cheek syndrome » respiratory infections, e.g. Influenza, SARS » gastrointestinal e.g. norovirus associated diarrhoea » blood borne diseases e.g. Hepatitis B, C and HIV » more sinister diseases e.g. Ebola, Lassa fever, Yellow fever.

Cannot be classified as either

Viruses

The Transmissible Spongiform Encephalopathies 8 are the important

exemplar that has particularly exercised the UK since the advent of Bovine Spongiform Encephalopathy (BSE) in cattle and its spill- over into the human population as variant Creutzfeldt-Jacob Disease. Other forms exist and all pose the same risk to the decontamination community

Cannot be classified as either

Infectious proteins

Table 1.1 : Organisms and infections

Viruses and infectious proteins are not considered living organisms as they are incapable of independent replication. In the case of viruses, they are essentially complex inert chemical collections outside a host cell but once they gain access to an appropriate cell, can use the host processes along with their own DNA or RNA to replicate.

Transmissible Spongiform Encephalopathies 8 (TSE’s) by contrast are caused by misfolded prion proteins being passed from one person or species to another although the process is not entirely understood. Transmission has been via ingestion of meat, particularly processed as in variant Creutzfeldt-Jacob Disease (vCJD) but also through human meat consumption (kuru), by blood (vCJD), through mutation direct in the brain in sporadic CJD (sCJD), via tissue transplantation (sCJD) e.g. corneal transplants and in rarer genetic forms of TSE e.g. Fatal Familial Insomnia. Once the abnormal prion protein presents to the brain, normal prion protein as it is made in the brain uses the acquired abnormal protein as a template and lays down sheets of the protein (amyloid) that leads to degenerative brain disease, which is inevitably fatal. The decontamination community is therefore particularly interested in these replicating proteins that are capable of being transmitted by body tissues and medical devices. These transmissible proteins remain an ongoing, if not entirely quantified threat. Gill et al 9 estimated the prevalence of vCJD in the UK population as 493 per million population. The potential threat from vCJD compared to sCJD or familial forms, is that the risk tissues are not limited just to the central nervous system but also include lymphoid tissue distributed throughout the body. For the decontamination professional, proteins are more difficult to remove and destroy and have required the UK to continue to be concerned about protein removal. This is the reasoning behind keeping instruments moist before reprocessing, and to ensure systems remove protein with use of protein detection methodology during validation and audit of the decontamination processes.

Difficulty of cleaning and/or protein removal has led to increased single use instruments being utilised to manage these risks e.g. dental reamers, ophthalmic tonometers or where the patient has a risk of CJD.

There has also been a debate around Alzheimer’s disease 10 and its similar abnormal protein deposition in the brain. While the risks seem remote, we cannot afford to let our guard down. Collins et al 11 demonstrated that surgical procedures were significantly associated with the development of sporadic CJD. Therefore, the cleanliness including protein removal from surgical instruments must remain an important focus, rather than thinking sterilisation will act as a final inactivation step, which it does with all other organism types in Table 1.1

What is infection and healthcare infection?

As Table 1.1 illustrates, there is huge variation in the types and sources of infections that can beset us from the very mild to the very high risk. Infections can be transmitted from person to person through natural routes as we mix in social situations, which can include personal mixing in healthcare premises. Traditionally in a hospital context, community acquired infections are those seen within the first 48 hours of admission to hospital. Anyone acquiring an infection after 48 hours of admission will be considered a hospital acquired infection. However, modern healthcare has moved to a much more fluid state between primary and secondary care that we are now favouring the generic term of healthcare associated infection. By its very nature, all surgery and other invasive medical device use makes the patient vulnerable to infection. As soon as the surgeon’s knife breaches the skin, the wound immediately puts the patient at risk of infection as underlying tissues are exposed to bacteria that do not normally have access to subcutaneous or deeper tissues. Similarly with endoscopies, albeit the risks may be lower but never absent as with the case of Hepatitis B transmission via a trans-oesophageal echocardiograph (TOE) probe. The surgeon however has offered surgery because on balance they have assessed with the patient that the benefits of surgery outweigh the risks of infection. Similarly, antibiotics may be prescribed due to pre-existing infection or as prophylaxis, to support the patient and help the patient’s immune system overcome or prevent infection.

What causes an immunocompromised state?

The immune system 12 is responsible for “policing” the body, recognising, removing and destroying foreign substances and cells, including cancer cells and infecting microorganisms. Immune defences however are broader than the cells of the immune system and effector substances they produce. The skin and intact mucous membranes are the first line of defence. Breaches of normal defences include insertion of peripheral or central venous catheters, urinary catheters, endotracheal tubes, medical devices: pacing wires, heart valves, implanted joints, urinary and biliary stents, arterial stents etc. As well as breaching normal defences, medical devices can allow for the deposition of a biofilm over time, which can include bacteria and therefore be a constant source of ongoing potential infection. Most patients in secondary care will be immunocompromised to a greater or lesser extent because of the procedures, medical devices and drugs used to support them, as indicated in the preceding paragraph. The more healthcare interventions used with a patient to manage an illness, the more immunocompromised they can become and the greater their susceptibility to infection. The risk of healthcare associated infection in a cancer patient already on immunosuppressive treatment who has just undergone major cancer surgery, including the use of prophylactic antibiotics will be at considerable risk of infection with antibiotic resistant bacteria.

Biofilms

Biofilms are important in healthcare 13 but also to the decontamination processes. A biofilm is a complex mix of protein, cellular deposits, and bacteria, tightly bound to a surface. In healthcare, biofilms can be associated both spontaneously in tissue and with indwelling medical devices. Some chronic wounds will develop a biofilm and to achieve wound healing it will be necessary to remove the biofilm. Similarly, a vegetation on a heart valve associated with endocarditis is a type of biofilm. Getting antibiotics into these complex biofilms is very difficult because by their very nature, they do not have a blood supply, which is why simply prescribing an antibiotic for a chronic wound has little effect other than to select for multi-drug resistant organisms. Endocarditis requires very high doses of antibiotics to set up a diffusion

gradient and try to get penetration into the vegetation. This is not always successful and may necessitate surgical intervention, removal of the diseased heart valve and implantation of a prosthetic device.

With implanted medical devices, many have lumens used to hold open natural tubes and are implanted to allow the passage of fluids. Examples include urinary, biliary and arterial stents etc. They will pick up debris from the different body fluids that pass through the natural tube and are also at risk of acquiring bacteria. These can find a niche and establish a colony, which with time can escape and establish new infections at a remote site. The difficulty with any implanted device is the device itself does not have a blood supply and therefore getting antibiotics into the biofilm is difficult and while an infection can be suppressed with antibiotics, killing those embedded deep in the biofilm is essentially impossible and eradication of this source of infection requires removal of the device. This will not be an easy decision and will require the clinical team to risk assess what the best course of action is for the patient and then discuss options. For the decontamination scientist, biofilms can similarly be associated with hinged joints and complicated shapes in surgical instruments and the multiple channels associated with various types of endoscopes. Such biofilms will develop over time if the device is not adequately cleaned. High temperature steam sterilisation is effective at killing bacteria but when present in biofilm matrices, processes can be compromised. Similarly, the presence of biofilm might prevent the denaturation of proteins and prion risk may remain. Where chemical decontamination is undertaken as in endoscopy, if the biofilm cannot be removed by cleaning, then the chemical decontaminant is unlikely to penetrate the biofilm and bacteria will survive and have the potential to be passed to a future patient.

The Challenge for the Decontamination Scientist

There is a variation in the susceptibility of the different infectious agents, which is illustrated in Table 1.2:

Microorganism types Examples

More resistant to Inactivation

Prions

Creutzfeldt-Jacob disease (CJD), Scrapie

Dormant Microorganisms Bacterial spores

Geobacillus stearothermophilus, Clostridioides difficile, Cryptosporidium, Giardia, Ascaris, Schistsoma

Protozoal Oocysts / cysts Helminth eggs

Mycobacterium tuberculosis, M. avium, M. Chimaera Poliovirus, papillomavirus, Parvovirus, Rhinoviruses

Mycobacteria

Small, Non-enveloped viruses

Dormant Fungi (Spores

Aspergillus and Penicillium spores

Cryptosporidium, Giardia, Ascaris, Schistosoma

Vegetative Helminths Vegetative Protozoa

Vegetative Fungi Moulds Yeast

Aspergillus, Penicillium Candida

Pseudomonas, Escherichia coli, Acinetobacter

Gram Negative bacteria

Large Non-Enveloped Viruses

Adenovirus

Staphylococcus aureus, Streptococcus pyogenes Human immunodeficiency virus (HIV), Influenza virus, Hepatitis B virus (HBV)

Gram Positive Bacteria

Less Resistant to Inactivation

Enveloped Viruses

Table 1.2 illustrates the relative difficulty in stopping replication of these groups of infectious moieties that the decontamination scientist is seeking to remove (used with kind permission of Gerald McDonnell)

Selecting the right decontamination/sterilisation method will not only depend on the nature of the agents involved but also the other factors described in this chapter. This will require a risk assessment with subsequent risk management, which is discussed in a later chapter.

References / Sources

1 National Institutes of Health. Human microbiome project defines normal bacterial makeup of the body. U.S. Department of Health and Human Services NHI News 2012 available at: https://www.genome. gov/27549144/2012-release-nih-human-microbiome-project-defines- normal-bacterial-makeup-of-the-body

[Accessed 16th Nov 2025]

2 Sender R, Fuchs S, Milo R. Revised estimates for the number of human and bacteria cells in the body. PLoS Biol. 2016 Aug 19;14(8):e1002533. doi: 10.1371/ journal.pbio.1002533 available at: https://pmc.ncbi.nlm.nih.gov/ articles/PMC4991899/

[Accessed 16th Nov 2025]

3 Gilbert J, Blaser MJ, Caporaso JG, Jansson J, Lynch SV, Knight R. Current understanding of the human microbiome. Nat Med. 2018 Apr 10;24(4):392– 400. doi: 10.1038/nm.4517 available at: https://pmc.ncbi.nlm.nih.gov/ articles/PMC7043356/

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4 Hoecker JL. I’m breastfeeding my newborn and my baby’s stool is yellow and mushy. Is this what I should expect? Mayo Clinic Healthy Lifestyle – Infant and toddler health. Available at: https://www.mayoclinic.org/healthy-lifestyle/ infantand-toddler-health/expert-answers/baby-poop/faq-20057971

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Anon. Definition of “micro.” Wiktionary the free dictionary available at: https://en.wiktionary.org/wiki/micro-#:~:text=Translingual- ,Etymology,mikr%C3%B3s% 2C%20

[Accessed 16th Nov 2025]

6 Fuerst , J. A. (2010) Beyond Prokaryotes and Eukaryotes : Planctomycetes and Cell Organization. Nature Education 3(9):44 available at: https://www.nature. com/scitable/topicpage/beyond-prokaryotes-and-eukaryotes-planctomycetes- and-cell-14158971/

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7 ByJu’s The learning App, Introduction: Prokaryotes And Eukaryotes available at https://byjus.com/biology/prokaryotic-and-eukaryotic-cells/

[Accessed 30th Dec 2025]

8 National Institute of Neurological Disorders and Stroke. Transmissible spongiform encephalopathies. available at: https://www.ninds.nih.gov/health- information/disorders/transmissible-spongiform-encephalopathies

[Accessed 16th Nov 2025]

9 Gill N. Spencer Y, Richard-Loendt A et al. Prevalent abnormal prion protein in human appendixes after spongiform encephalopathy epizootic: large scale review. BMJ 2013;347 available at: https://www.bmj.com/content/347/bmj. f5675

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10 Abbott A. ‘Transmissible’ Alzheimer’s theory gains traction. Nature news 13/14 December 2018 doi: 10.1038/d41586-018-07735-w available at: https://www. nature.com/articles/d41586-018-07735-w

[Accessed 16th Nov 2025]

11 Collins S, Law MG, Fletcher A, Boyd A, Kaldor J, Masters CL. Surgical treatment

and risk of sporadic Creutzfeldt-Jakob disease: a case – control study. Lancet 1999 Feb 27;353(9154):693-7 doi: 10.1016/s0140-6736(98)08138- 0 available at: https://www.thelancet.com/journals/lancet/article/PIIS0140- 6736(98)08138-0/abstract

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12 Newman T. How the immune system works. Medical News Today 2023 available at: https://www.medicalnewstoday.com/articles/320101

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13 Prinzi A, Rhode R. The role of bacterial biofilms in antimicrobial resistance. American Society for Microbiology 2023 available at: https://asm.org/ Articles/2023/March/The-Role-of-Bacterial-Biofilms-in-Antimicrobial-Re

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Decontamination Life Cycle 2

This chapter describes the principles relating to the Decontamination life cycle as shown below. Whilst this diagram was initially created for surgical instrument processing, it can be related to any medical device requiring decontamination. Local systems of work should define how each of the stages will be controlled, starting with the notification of the need for decontamination of a device, (acquisition) to its final return to the user, fit for purpose and ready for use or eventually, its disposal.

As well as defining how each stage of the life cycle is managed, the model also highlights the extent to which decontamination affects the whole organisation and not just those responsible for reprocessing medical devices. The centre of the life cycle highlights the elements which also need to be considered at all stages.

The Location - where is decontamination undertaken? How far away from the point of use is it? Will this delay reprocessing, making the device more difficult to clean?

The Facilities - are they dedicated for the purpose? e.g. a sterile services department or endoscopy decontamination unit? (See Health Building Note 13) 1 or is decontamination undertaken in a treatment area or ward and department? Is there a clear segregation of clean and dirty areas to minimise recontamination of clean devices? Equipment - what is recommended by manufacturers to decontaminate the devices? What do their instructions for use (IFU) state? Who is responsible for testing and maintenance of any equipment used? e.g. washer disinfectors; sterilisers etc. What standards apply to the equipment?

Management - who is responsible for ensuring decontamination is being undertaken to the appropriate guidance and standards? Are there clear governance arrangements in place? Is there an assurance framework?

Policies and Procedures - are there local polices and procedures describing the way that devices are to be processed? Do these describe how decontamination should be undertaken and what is the chosen method? Is there a formal quality management system (QMS) in place? Traditionally, decontamination of devices has been the responsibility of the departmental heads of specialist units, for example sterile services, endoscopy units, theatre suites etc. but with the increased use of probes and endoscopes used for diagnosis e.g. ultrasound probes, transvaginal and transrectal probes, nasendoscopes etc., decontamination is often undertaken at the point of use. Centralised automated processing should always be the preferred option however, it is acknowledged that this cannot always be applied due to local circumstances. Irrespective of the location of decontamination of medical devices, there must always be a nominated lead responsible for all activities including staff training and competency.

Whilst individual functions may have a nominated lead and be undertaking decontamination according to extant guidance, the organisations’ executive team (ultimately the Chief Executive Officer [CEO]) remain fully responsible and accountable

for all device decontamination irrespective of the ‘Provider’, and this includes any externally contracted services. This liability cannot be transferred; the CEO is vicariously responsible for his/her organisational activities.

The life cycle model above highlights each stage of the decontamination process through which surgical instruments, endoscopes and other medical devices pass before every use. Effective decontamination requires the attainment of acceptable standards at all stages. Failure to address issues in any of these stages may result in inadequate decontamination and the device not being fit for purpose. At all stages of reprocessing, the following issues need to be taken into account:

• The location and activities where the decontamination takes place • Facilities and equipment at each location

• Ensuring that any equipment used is validated, routinely monitored, maintained and tested in accordance with the manufacturer’s guidelines, legislation and standards • The existence of effective management arrangements • The existence of written policies and procedures detailing all aspects of decontamination work • Appropriate training and education of the operators carrying out the decontamination It is not the intention of this document to duplicate information that is readily available. ‘A guide to the decontamination of reusable surgical instruments’ report was written by NHS Estates in 2003 (now superceded by the HTM 01-01) which is still relevant today. This document was developed in support of the National Decontamination Programme and an update report titled, ‘The decontamination of surgical instruments in the NHS England Update report’ 2 is available on the UK Parliament website to view.

Manual versus Automated Processing

Within the healthcare environment there are many examples of decontamination of medical devices. Central processing in a certified Sterile Services Unit, employing a formal quality management system i.e. ISO 13485 Quality Management System for Medical Device Manufacturing, is the preferred option.

This is an internationally agreed standard that sets out the requirement for a quality management system specific to the medical devices industry pertinent to healthcare facilities. Centralised processing routinely covers surgical instruments and flexible endoscopes and accessories, however some organisations have been able to incorporate decontamination of ultrasound probes and TOE probes, the latter posing a challenge protecting the electronic components during automated processing. Many intracavity devices, i.e. those inserted via natural orifices of the body, are decontaminated at clinical ward dept level often at the bed side using a manual process involving decontamination with wipes. The disadvantages of this approach is in reproducing a consistent decontamination process, due to the likelihood of human error, allowing variations in the application of best practice 3 . There are a variety of wipes available for device processing with very different instructions for use. The contact time of the chemicals used on these wipes is critical for effective decontamination 4 . Training in the use of these wipes is essential and can be provided by the manufacturers of the wipes to ensure decontamination is achieved. The environment in which decontamination takes place in wards and departments will often not be dedicated for the purpose as opposed to an SSD or Endoscopy unit where decontamination is the only activity taking place. Infection Prevention and Control practices are often compromised, due to the environment, and there is also a greater risk of decontaminated devices becoming contaminated before further use due to inadequate protection and storage. Standard operating procedures describing the step-by-step actions are needed for the various devices, and routinely exist, however audits often show that there is significant variation in the application of the steps described. This is one of the reasons central processing involving automated processing is the preferred method of decontamination. Other advantages include the use of validated ‘processes’ washer disinfectors, chemicals, sterilisers etc. Many decontamination failures have been found to relate to manual medical device decontamination. For example, there have been serious failures in decontamination of Transoesophageal Echo (TOE) and Laryngoscope handles 5 which have caused patient harm. The MHRA alerts describing these failures highlighted manual processing which concentrated on the ‘working element’ that came into direct patient contact and not the whole of the medical device which poses an equal infection risk to the patient if not processed appropriately.

Some medical device manufacturers’ instructions state that pre cleaning needs to be carried out immediately after use in theatres, prior to sending to the SSD. An example of this are handpieces for phacoemulsification used in eye surgery. 6,7

The USER

Health Technical Memorandum (HTM) 01-01 series Part A 8 defines the roles and responsibilities of key personnel involved in the management of medical devices within an organisation. The term USER has many definitions including the practitioner using a medical device, but also in terms of the HTM, cover the individual who is responsible for the day-to-day management of the decontamination of reusable surgical instruments, and for seeing that the decontamination process is operated safely and efficiently. In the case of the SSD this would be the manager, however at ward and department level could be the senior ward manager. The USER is also responsible for the operators of any decontamination equipment and for the equipment being fit for purpose. Large organisations often struggle to ensure that everyone involved in decontamination understand their roles and responsibilities. A report by the Health Services Safety Investigation Body (HSSIB) 9 in 2022 highlighted the need for improvement to governance arrangements in large healthcare organisations.

Medical device labelling and symbols

The international standard for medical device labelling which employs symbols is ISO 15223-1 and aims to provide a visual and a universal means by which device information can be imparted to users. There is always a risk of misinterpretation when any language translation is undertaken. Hence the use of symbols. A few of the most commonly used symbols are reproduced below, together with their meaning:-

Batch Code

Serial Number

Attention - see instructions for use

Date of Manufacture

Use by Date

Sterile

Sterilised by Irradiation

Sterilised by Heat

Sterilised by Vaporised Hydrogen Peroxide

Sterilised by Ethylene Oxide

The following symbol is used to indicate that a medical device should not be re-used i.e. Single Use

Decontamination Standards

Decontamination related Standards define how processes and equipment should be managed. It details testing and maintenance requirements for equipment and supports reproducibility of machine cycles so that devices are subjected to a consistent operation and product quality. Control of processes, for example, cleaning and disinfection, various forms of sterilisation are detailed in standards to ensure consistency of performance and outcomes for medical device management. These standards, whether they be British, European or International are used to describe agreed means by which processes, and equipment is managed. A British Standards Institute (BSI) group ‘CH/198 sterilization and associated equipment and processes’ is an example of a multi-disciplinary group comprising representatives from many healthcare professional bodies and commercial organisations that work

together in support of producing decontamination related guidance (See also Chapter 5, Legislation, Standards and Guidance)

Training and Competency of Staff

It is an organisation’s responsibility to ensure all staff are trained and competent for all aspects of their work. Decontamination is a specialist area and requires an in-depth technical knowledge by all those involved.

In England, Criterion 2 of the Health and Social Care Act 2008: Code of Practice on the prevention and control of infections and related guidance 10 highlights a wide range of responsibilities relating to cleaning and disinfection of environment, fixtures, fittings , medical devices , linen and staff training. There are equivalent statements made by all UK nations. (see also Chapter 12)

Shelf Life of Medical Devices

All packaged medical devices will be given a shelf life or expiry date. The responsibility for determining the expiry date is with the manufacturer. It is worth noting that the sterility of a packaged device is EVENT RELATED, therefore, if the packaging is compromised for any reason, the device expiry date becomes irrelevant. If packaging is damaged. then in the case of a reusable device, it should be reprocessed, and if a single use device, then it should be disposed of. The expiry date can be based on the packaging or the device itself. An example of this might be a material used in device construction that will deteriorate over time whilst the packaging will maintain sterility for many months or years, if stored and handled correctly. In these instances, the shelf life should be determined by whichever is the shorter period of time. The expiry date must be shown on the device packaging and for commercially produced devices, is usually shown with the symbol of an hourglass. The date of manufacture is depicted by an image of a factory. (see labelling symbols)

Storage of Medical Devices

Packaged medical devices should be stored in a controlled environment and dedicated for the purpose. Sterile stores, as they are often known, should not have sinks or water sources in them, as if packaging becomes wet, they should be considered compromised and be disposed of. Water or moisture, supports the ingress of bacteria and has the potential to contaminate contents. Sterile packs should be kept out of direct sunlight and away from the floor. Health Building Note 13 1 provides information relating to storage areas for sterile devices and provides a good generic list of conditions for ideal storage of sterile packs. Storage racking should be smooth and support air circulation. To ensure safe lifting and handling practices, heavy instrument sets should be placed on lower shelves, while lighter sets are best stored on higher shelves. Sets should not be stacked one on top of the other as this often results in torn wraps but may also damage the contents. Storage space in healthcare settings is always a massive challenge, never more so than in operating theatres, and corridors are often used for this purpose. Where this is unavoidable, sterile packs should be protected from damage and inadvertent contamination. All packaged devices should be covered and there should be procedures in place to ensure rotation of stock, whether this be commercially produced single use items or instrument sets and supplementary packs. Mobile trolleys are sometimes suitable for device storage depending on the type, for example flexible endoscopes and boxed surgical implants. In all cases a good checking system needs to be in place to ensure devices are rotated and used in date order. It is essential to have a named individual to manage all types of medical devices in storage at the point of use.

i For those wishing to learn more about CH/198 or for experts wishing to be considered for membership of this committee, search the BSI website. https://standardsdevelopment.bsigroup.com/committees/50081178

Trouble shooting - Surgical Instrument Staining

The following focuses on three areas, the manufacturing; logistics challenges; processing challenges. These notes do not encompass all information relating to the root cause of instruments staining but they do provide a starter for ten in a local investigation. 1. The Manufactuer a. Stainless steel for instruments should be as per ISO 7153 Surgical Instruments materials, Part 1: Metals 11 b. A validated passivation process should be used (see definition of passivation) c. An up-to-date validated decontamination process MUST be followed d. Instruments should be finished appropriately to reduce/mitigate wettability (see definition of wettability 2. Logistics challenges - post surgery a. Has there been a recent change in reprocessing? E.g. move to off site processing? Instruments sitting in a vehicle wet/dirty for prolonged periods? b. Is there saline used in the surgery and then left on the instruments? Saline is also a challenge regardless of logistics. c. Is a pre-cleaner used? Trial these and get the correct solution; do they have rust inhibitors? Leaving instruments in humid environment may help. (recommended that all instruments are kept moist after use and prior to the start of the decontamination process) Results will vary according to instrument finish. 3. Processing Challenges a. Are the chemistries used, compatible with the devices? Too high a pH can damage b. Is the water quality of acceptable levels? Too much chloride/minerals will cause staining and silicates too. Regularly check the quality of the water used for washer c. Are instruments suitably dry when they come out of the WD? d. Ensure instruments are not closed (recommended to leave ratcheted instruments on the first rachet only) a combination of lack of oxygen and water will cause staining.

e. Are instruments damaged? Any surface damage will leach free iron when the instrument is processed. f. Ensure only stainless steel of ISO 7154 is used for repaired parts and medical devices. g. Do not use non- medical device quality items in trays of instruments i.e. stationary shop bulldog clamps or spoons from restaurants. h. Check the passivation layer on new instruments by running them through a few wash and sterilisation cycles to observe any staining occurring.

The above introduction to instrument staining trouble shooting, has been reproduced with kind permission by Dan Coole, MD Surgical Holdings in May 2024. Additional information can be found in an excellent document called, ‘reprocessing of instruments to retain value’ ii also known as the “Red Book”.

ii For more excellent reading on surgical instruments and instrument reprocessing https://www.reda-instrumente.de/wp-content/uploads/Version-11-Englisch.pdf

References / Sources

1 Department of Health. Health Building Note 13: Sterile services department available at https://www.england.nhs.uk/publication/planning-and-design-of- sterile-services-departments-hbn-13/

[Accessed 16th Nov 2025].

2 Depertment of Health NHS. The Decontamination of Surgical Instruments in the NHS England, Update report “Step Change”, available at http://data.parliament. uk/DepositedPapers/Files/DEP2008-1265/DEP2008-1265.pdf

[Accessed 16th Nov 2025]

3 C.R. Bradley et al, Guidance for the decontamination of intracavity medical devices: report of a working group of the healthcare Infection Society. Journal of Hospital Infection 101 (2019) 1-10. doi: 10.1016/j.jhin.2018.08.003 available at https://his.org.uk/media/i4rj5pnj/guidance-for-the-decontamination-of- intracavity-medical-devices-the-report-of-a-working-group-of-the-healthcare- infection-society.pdf

[Accessed 16th Nov 2025]

4 Medicines and Healthcare products regulatory Agency, Medical Device Alert MDA/2013/019 Detergent and disinfectant wipes used on reusable medical devices with plastic surfaces available at: https://assets.publishing.service.gov. uk/media/5485abb0ed915d4c10000243/con254853.pdf

[Accessed 16th Nov 2025]

5 Medicines and Healthcare products regulatory Agency Medical Device Alert MDA/2012/037 Reusable transoesophageal echocardiography, transvaginal and transrectal ultrasound probes (transducers) available at: https://assets. publishing.service.gov.uk/media/5485abf1ed915d4c0d000261/con160567.pdf

[Accessed 16th Nov 2025]

6 Medicines and Healthcare products Regulatory Agency, Handpieces used in phacoemulsification technique of cataract removal: need for careful cleaning (DSI/2021/009) available at https://www.gov.uk/drug-device-alerts/handpieces- used-in-the-phacoemulsification-technique-of-cataract-removal-need-for- careful-cleaning-dsi-slash-2021-slash-009

[Accessed 16th Nov 2025]

7 IHEEM. Top tips on decontamination of phacoemulsification handipieces. Advice from the IHEEM Decontamination Technical Platform [DTP] available at https://www.iheem.org.uk/iheem-guidance-on-the-decontamination-of-phaco- handpieces/

[Accessed 16th Nov 2025]

8 Department of Health, Health Technical Memorandum 01-01: Management and decontamination of surgical instruments (medical devices) used in acute care, Part A: Management and provision available at https://www.england.nhs.uk/wp- content/uploads/2021/05/HTM0101PartA.pdf

[Accessed 16th Nov 2025]

9 Health Services Safety Investigation Body, Investigation report, Decontamination of surgical instruments available at https://www.hssib.org.uk/ patient-safety-investigations/decontamination-of-surgical-instruments/

[Accessed 16th Nov 2025]

10 Department of Health and Social Care, Health and Social Care Act 2008: code of practice on the prevention and control of infections and related guidance (2022) available at https://www.gov.uk/government/publications/the-health-and-social- care-act-2008-code-of-practice-on-the-prevention-and-control-of-infections- and-related-guidance/health-and-social-care-act-2008-code-of-practice-on-the- prevention-and-control-of-infections-and-related-guidance

[Accessed 16th Nov 2025]

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