After a serious safety incident, in which surgery was performed on a patient with a contaminated surgical instrument, the NHS England’s independent body, the Healthcare Safety Investigation Branch (HSIB), launched an investigation in August 2021. The resulting report, ‘Decontamination of surgical instruments’, published in May 2022, identified several gaps in the UK healthcare system that could risk patient safety as a result of contaminated surgical devices. These ranged from a lack of national reporting and gaps in governance to “significant variance” in the training and competence of staff responsible for the decontamination of surgical instruments. The report also raised concerns about how surgical instruments were designed, which it said did not give adequate consideration to the decontamination process required after use. Designing devices in a way that makes them difficult to clean increases the risk of patient contamination.
In addition to improving instrument design, the report also recommended establishing national reporting mechanisms, enhancing governance and assurance processes, and standardising training and competency frameworks. The Medicines and Healthcare products Regulatory Agency (MHRA) is responsible for regulating the UK medical devices market and enforcing stringent Good Manufacturing Practice (GMP) to ensure products are safe for patients and meet quality standards. One of the important criteria for medical device regulation is based on whether the device is invasive or non-invasive and the length of time the device comes into contact with the patient.
“Where possible, medical devices which are implanted in patients will be terminally sterilised (the process of rendering medical devices and materials free of all forms of microbial life before they are packaged for distribution and used) using an approved method regulated according to the Medical Devices Regulations 2002 (SI 2002 No 618, as amended) (UK MDR 2002),” said a spokesperson for MHRA. Its online guidance offers information about the potential risks that should be considered with regard to sterile and non-sterile best practices.
“There is no single main contamination risk in sterile and non-sterile manufacturing – multiple risks exist, all of which must be managed concurrently to ensure product safety,” according to the MHRA.
“The MHRA does not recommend specific sterilisation methods, it requires manufacturers to validate and control their chosen processes to ensure device sterility. The selection of an appropriate sterilisation method should consider the device’s material, design, and intended use, adhering to regulatory standards and guidelines,” said the MHRA spokesperson.
Hidden dangers of biofilm accumulation
Despite a range of sterilisation technologies being available, steam sterilisation is the most widely employed method around the world, according to the UK’s professional body for decontamination science practitioners, the Institute of Decontamination Sciences (IDSc).
“Steam sterilisation is relatively cost-effective, extremely effective on organic matter, easily installed and repeatable,” says Rob Warburton, the ISDc’s Trust Decontamination Lead. However, the process is not appropriate for use on all devices – some medical instruments are too heat-sensitive and delicate.
“Invasive devices are generally made out of stainless steel and have to undergo steam sterilisation. But some devices – such as flexible endoscopes, for example – are heat liable so they can’t be subjected to that process,” explains Warburton. Flexible endoscopes comprise a flexible plastic tube with internal channels and a camera on the tip. These complex and expensive devices are easily damaged and, therefore, more suited to lowtemperature sterilisation methods. However, these often involve chemicals. And when chemicals are involved, the cost of the process rises along with the hazards of toxic emissions.
“Vapourised hydrogen peroxide is a low-temperature sterilisation method that is almost as effective as steam, but it does require a lot of venting because it’s a noxious chemical so you can’t sterilise loads to the same size you can with steam,” says Warburton.
Then there’s ethylene oxide sterilisation, which Warburton describes as an effective but very expensive and hazardous sterilisation agent. Despite its sweet smell, the colourless gas is extremely flammable and toxic. Its ability to kill organic matter makes it an effective sterilising agent but also accounts for its potential to cause cancer in humans who are exposed to it. Devices that are sterilised with ethylene oxide include wound dressings, lateral flow devices and specialised devices that are used inside the body. As with vapourised hydrogen peroxide, the process also requires a lot of venting and stringently controlled laboratory environments.
“It’s the most dangerous option because it’s the most volatile,” says Warburton. “It’s a toxic gas and if there are any naked flames around its extraction it can cause an explosion.”
Also requiring a stringently controlled process, along with a factory-sized hangar, is the radiation method, which is used for the mass sterilisation of consumable medical instruments. Warburton believes one the biggest blind spots in healthcare in terms of sterilising and decontaminating medical instruments is biofilm accumulation. Biofilm is a sticky layer of bacteria that can accumulate on surfaces that are hard to access, such as the inner channels within the tubes of endoscopes. These bacteria can potentially contain pathogens.
“Several studies on biofilms over the past six to seven years have suggested they’re resistant to highlevel disinfection. It’s highly likely the biofilm will contain pathogens,” says Warburton. Biofilms can also form on catheters, which can lead to catheterassociated urinary tract infections (CAUTIs).
Innovative solutions for biofilm control
The biofilm issue has been researched by both The University of Sheffield and Sheffield Hallam University. The former has developed strategies to treat biofilm infections in medical devices, including an integrated system for detecting and treating biofilms on urinary catheters, plasma polymerisation of nitric oxide release coatings to inhibit biofilm formation and development of strategies for treating biofilm infections in indwelling medical devices. Meanwhile, Sheffield Hallam University has researched biofilm prevention through antimicrobial surfaces and ways of controlling biofilm formation on urinary catheters. Technology has also come up with some potential solutions in the form of two innovative devices for decontaminating reusable medical instruments: the BIARmed Safe CleanBox and the Tiny Air automated decontamination system.
The BICARmed Safe CleanBox is a closed chamber that uses a ‘bicarbonate spray’ to deep clean reusable medical instruments – effectively pre-cleaning them before sterilisation. This pioneering technology was initially conceived in Italy to clean Formula 1 motor racing components but has now been applied to healthcare. The NHS Northern Care Alliance (NCA) has been the first UK healthcare trust to use the equipment.
“The increasing complexity in instrument design and shape has meant that manual cleaning techniques require intense and repetitive application to achieve the desired result,” says David Taylor, NCA decontamination technician. “However, the CleanBox enables us to accomplish this in one swoop, with full confidence, and without the need to don uncomfortable PPE.”
“The CleanBox is a great addition to our facility because it better protects us from the substances on soiled devices. Our impact upon the environment is also reduced because it lessens our dependence upon the harmful chemicals and single-use plastics required by traditional pre-cleaning techniques,” adds Kelly Hulse, NCA decontamination technician. CleanBox is used at the Royal Oldham’s Hospital Sterilisation and Disinfection Unit to re-sterilise medical devices across the NCA footprint. Warburton also praised the Tiny Air automated decontamination system, which is designed for the automated pre-cleaning of surgical instruments. The manufacturers claim this new-tomarket “environmentally sustainable innovative technology cleans with cold water and no chemicals in two minutes”. Said to be six times faster than the manual sink process and to increase the production capacity of sterile services departments by 10%.
Warburton is hopeful that further automation of decontamination processes will raise standards in future. “Decontamination practices need to be repeatable. We’ve got the science and the technology, but it’s not mainstream yet,” he says. “People are nervous about moving away from sinks, but we know that contaminants around drains are a big risk from an infection control point of view.”
Investing in automated decontamination technology offers multiple benefits, believes Warburton, which justifies the initial capital outlay. For example, fewer instruments are rejected at the inspection stage and the number of stages of the process are reduced, as is labour. In the long-term, these amount to savings, he says. “I’ve done a business case for my hospitals and we’re actually going to have a saving by moving away from sinks and cleaning brushes.
“Right now, everyone’s playing watch and wait to see what the pitfalls are, but I can see this technology being widely used in future.”
Critical changes to classification
In the meantime, Warburton calls for endoscopes to be reclassified from semi-critical to critical, according to the Spaulding Classification system. Originally proposed in 1957, the system remains widely used for defining the disinfection and sterilisation of contaminated reusable medical devices and surgical instruments.
“We know there’s a risk of biofilm accumulation, so we need to reclassify these devices as critical. They need to be sterilised as a minimum between patients because they come into contact with the sterile cavity.”
He also recommends more widespread use of prepacked sterile implants. NHS Scotland has completely migrated to them, but not so for NHS England.
“The IDSc is encouraging the best practice of going prepack sterile through its membership, but resistance is coming from individual hospitals and the orthopaedic consultants in England,” says Warburton.
So, it appears that the technology is on its way and change could be coming – it’s just a question of how long it will take.
