Could UV-C LEDs light up decontamination?

The NHS has been utilising a combination of washer-disinfectors (WDs) and autoclaves for over 50 years, with obvious industry improvements over time to reduce power and water consumption. They are the accepted ‘go-to’ solution for sterilisation of reusable surgical equipment from operating theatres, as well as reusable devices that do not require sterilisation. Many NHS organisations, however, have no other process to clean and disinfect them for safe re-use.

Although some of the most sophisticated WDs and autoclave models now on the market are more efficient than earlier models, many devices installed in NHS hospitals and in daily use consume between 150 and 700 litres of water per cycle.¹ They also consume the same power per cycle as an average UK domestic house uses in a 24-hour period.² Neither of these consumption levels are sustainable or environmentally responsible. Until these WDs and autoclaves reach the end of their economic life, or fail to the point of being beyond economic repair, the cost to replace them is prohibitive. Unnecessary usage should thus be avoided whenever possible, and now there is a genuine alternative.

Potentially damaging temperatures

The reason for such excessive power and water consumption is that the temperature for thermal disinfection currently is 90 °C3 for 1 minute, or 80 °C for 10 minutes in a WD, and 117 °C (steam) for an autoclave. These temperatures are potentially damaging for many materials, and contribute to reducing the life of products being subjected to them.

WDs and autoclaves are inherently deployed in on-site Sterile Services Departments (SSDs), where many products and medical devices (MDs) are transferred to and from for sterilisation. These products require SSD specialists who often strip, pre-clean, and reassemble, the devices post-sterilisation. They are also responsible for inspecting the MDs before returning them to the relevant departments. However, in the same way that many laundry services were removed from NHS hospital sites (only 10 on-site NHS laundries now exist), many hospitals now outsource their SSD reprocessing to a third-party provider. This involves procuring multiples of the equipment, to support the time taken to transport to and from the provider, as well as the reprocessing time, and this can be a factor of 4 or 10 times the number of items required for daily use, dependent on the turnaround times.

The road miles and increased manufacturing of additional items to sustain the supply chain for reprocessing is in addition to the carbon footprint of the sterilisation equipment’s high power and water consumption. For devices unable to be subjected to these processes due to the ingress of water and steam, as well as the high temperatures, or that only require High Level Disinfection (HLD),⁴ there is the regular use of three-stage wipes or other chemical disinfection materials. Examples of these devices subjected to three-stage wipes are ENT video rhino-laryngoscopes and video laryngoscopes, and ultrasound probes, both cabled and cordless. Again, there is the potential over time for material damage caused by strong chemicals being used, and the operatives wear three sets of gloves to reprocess one device.

A counter-intuitive process

What has also become more prevalent over the years is the reprocessing of non-sterile items through the SSD, which is counter-intuitive. These are devices that can withstand the harsh environment, but by the device categorisation of ‘non-sterile’, do not need to be sent to an SSD. However, until very recently it has been the only recognised option for cleaning and disinfecting, to achieve HLD consistently, through a recognised and certified manual and automated process. Examples are scissors used in outpatient departments, reusable anaesthetic masks, and personal protective equipment (PPE) P3 half-face respirators.

However, through work that began during the pandemic with the PPE Reuse, Innovation and Sustainability Team that I headed up, things may be changing.

My team became responsible for identifying innovative, reusable PPE, suitable for health and care workers, with, at, or near, the point-of-use cleaning and disinfection. We engaged with numerous companies responding to the COVID pandemic. Many were switching production from core business activity or setting up new production facilities to manufacture PPE, as well as exploring possible innovative cleaning and reprocessing materials and equipment. These companies and products included the following, but this is not an exhaustive list:

• Transparent face masks (Contechs, Alpha Solway, Hello Face, Don & Low, Blue Tree Medical, Polar Seal, LJA Miers, Valmy SAS, and Northwest Medical).
• P3 half-face respirators (Hello Face).
• UK-manufactured surgical masks (Blue Tree Medical).
• Powered hoods and respirators (CleanAIR).
• Improved eye protection (Bollé Safety).
• UV-C disinfection and cleaning materials, (Mackwell Electronics, Rollins Consulting, Aqualution, and HOCL), as well as many others responding to the unprecedented challenges.

Work with eye protection and respiratory manufacturers

I was working with eye protection and respiratory manufacturers and suppliers to assess reusable products, their fit, form, and function, as well as the cleaning and disinfection for wearers to move from one ward to another without cross-contaminating, and without disposing of devices between wards. The Mackwell Electronics UV-C cabinet, with Bollé Safety eye protection, and the Hello Face respirator, would be the solution, eventually.

However, the focus was soon diverted, as Northampton General Hospital NHS Trust, along with others, was experiencing inconsistent and fragmented supplies of single-use anaesthetic masks. The Trust enquired if the Mackwell Electronics UV-C cabinet could disinfect reusable anaesthetic masks, as they are of a similar shape to the respirators, which is true. However, PPE is regulated by the Health & Safety Executive (HSE), and anaesthetic masks are regulated by the Medicines and Healthcare products Regulatory Agency (MHRA), with very different standards and requirements.

Open to the challenge

Mackwell Electronics was open to the challenge, and coincidently the new standard for UV-C disinfection cabinets and disinfecting rooms had just been published, in October 2022, (BS8628-2022). This was the new standard that Mackwell would need to be certified against to be able to reprocess MDs, following a proven cleaning cycle to remove soilage and debris. The cabinet had to be registered as a medical device, and to comply with the recently published Medical Device Regulations (MDR), which replaced the Medical Device Directive (MDD) in 2021.

PCC Sustainable Solutions had been involved with innovative disinfection and cleaning solutions through Envirosmart and Rollins Consulting. These included PATHISOL Hypochlorous Disinfectant, and innovative cloths from Decitex in France, with excellent performance over 500 washes, even when laundered through harsh industrial laundries, and non-linting. The integration of these with the Mackwell UV-C cabinet could solve cleaning and disinfection at or near the point of use.

Achieving the testing standards

The first step in achieving this, was the to achieve the testing standards for BS8628-20225 certification, which was undertaken by Test Labs, who Mackwell engaged in late 2023, and following range finder testing to assess the cycle duration required for the toughest organism in the standard, the full test was embarked upon, culminating in certification being achieved in January 2024. It is to date possibly one of the only, if not the only, certified disinfection chamber on the market.

Next was the evidence that the process worked on MDs, as testing to a standard only requires inoculated flat stainless-steel discs to be neutralised for the standard to be passed. Therefore, PCC Sustainable Solutions worked with Mackwell, and the Northampton Trust’s Infection Prevention and Control (IPC) team, to create the test scenario, including where to inoculate the anaesthetic mask to simulate real-world soilage. To then evidence effective cleaning and disinfection, post-inoculation (wearing in the real world), I wrote a detailed Standard Operating Procedure (SOP) on how to clean and disinfect the reusable anaesthetic masks. The SOP was needed to instruct the test laboratory on a repeatable process, which — once proven — would form the basis of the Instructions for Use (IFUs), which, when followed, produce a safe, reusable MD, reprocessed to consistently achieve HLD, in a more sustainable, affordable, and environmentally-friendly process. For the simulated real-world testing, masks were inoculated with Geobacillus spores suspended in artificial saliva, and then reprocessed according to the SOP, which Test Labs followed, achieving a Log 5.3 reduction of the pathogen inoculated onto the anaesthetic mask.

Trial initiated

On successful completion of both the certification and the simulated real-world testing, the trial that was being planned while testing was ongoing commenced in February 2024. The outcome of the trial was successful, other than some anaesthetists commenting negatively on the required rigidity of the silicone reusable anaesthetic masks under pressure to achieve a seal with the patient. The anaesthetists’ feedback brought about the creation, by Mackwell, of a reusable air-cushioned anaesthetic mask, which is reusable 50 times. This reduces waste, CO2e, and spend year on year, eliminating some 900 tonnes of CO2e, and 160 tonnes of waste, annually.

The NHS currently uses circa two million single-use anaesthetic masks via NHS Supply Chain annually,⁶ which — if replaced with reusable anaesthetic masks, processed using this innovative process, would generate a reduction of 120 tonnes of waste and 765 tonnes of CO2e, following widescale adoption. Mackwell Health, a division of Mackwell Group, was also formed during this period. Since the first trial, Mackwell Health and PCC Sustainable Solutions have developed reprocessing, with, at, or near, point of use cleaning and disinfection for multiple MDs and PPE, with more to follow.

Part of the certification process

For clarity, the products used in the testing and subsequent trials are part of the certification process; hence high-quality Decitex microfibre, both single-use, to overcome laundry issues, and launderable (non-linting) are always used. The PATHISOL or Spectricept Hypochlorous Disinfectant at circa 600 ppm ensures rapid efficacy against C.difficile spores.

As well as this development work, there has been work in the background, commissioned and undertaken by Eco Medic,⁷ to produce the carbon Life Cycle Analysis (LCA) of the single-use devices, compared with reusable devices, reprocessed using Hypochlorous disinfectant, microfibre, and UV-C. Table 1 shows that the benefits are significant and independently verified. These findings are replicated on reprocessing other devices using the same methodology.

Reducing the ‘vast numbers’ of PPE products still in use

Following on from the first trial with reusable anaesthetic masks and subsequent trials with other MDs, work has also continued into PPE reprocessing to reduce the vast numbers of single-use PPE products still in use. So, given that there is no standard for the cleaning of eye protection or respirators in health and care settings, reprocessing PPE is much simpler, but is it safe enough?

Wiping with wet wipes

Currently, wiping PPE with wet wipes is still common practice, despite no evidence of the efficacy of wet wipes on silicone, rubber, and soft materials. This is an area where I and PCC Sustainable Solutions continue to press for a relatively simple amendment to the standards for reusable PPE to include a cleanliness level. This would provide clarity for manufacturers, to allow consistent and appropriate testing to evidence that the cleaning and disinfection in their Instructions for Use (IFUs) meets the standard. The suggested products and standards include half-face respirators (EN140, EN1827), and, for eye protection, EN166. This is timely given the drive for sustainability and more reusable PPE, as stated in the PPE Strategy8 in 2022, for more reusable PPE from on- or near-shore production for future pandemic preparedness, alongside the Greener NHS Net Zero plan,⁹ also launched in 2022, to reduce the NHS carbon footprint to Net Zero by 2040 and 2045. It also supports the Waste Strategy,¹⁰ launched by the NHS on 7 March 2023, where £11 m annual in revenue savings should be achieved if successful.

Detailed SOPs

In fact, given the lack of a standard, the work that I undertook, to integrate devices and processes, with Hello Face respirators, Bollé Safety eye protection, Mackwell Health UV-C, and Rollins Consulting, to adopt the cleaning and disinfection developed for reusable MDs provides a safe, reusable product. This includes detailed SOPs and training material, with reprocessing record cards, and HSG 53 records for compliance to monthly inspections of the respirators. Collectively, this enables the move to safe, sustainable high-quality PPE. The Hello Face P3 Protect, and soon-to-be transparent Hello Face P3 Connect respirators, are currently in use in NHS Trusts trials, and for user/patient feedback to reduce the use of single-use visors and FFP3s.

Given that reusable products pay for themselves in less than a month, typically last 2-5 years, and address poor fitting and poor quality compared with many single use devices, they have many clear benefits, yet despite learnings from the pandemic and the ongoing COVID-19 enquiry, there remains much more to be done to move away from single-use products and PPE.

With the success of the trials, and more ongoing — including on other medical devices and PPE, combined with the significant reduction of the UV-C cycle time from 20 minutes to 5 minutes within a year from first certification, the time appears ready to deploy more certified UV-C to reprocess MDs requiring HLD. This will ease pressure on SSDs, reduce reprocessing costs, and significantly cut CO2e, while potentially extending the life of MDs and other devices. The UV-C cabinets are ‘plug and play’, and lightweight, with the Minibox weighing 7 kg, and a cycle costing £0.10, compared with a WD cycle costing £1.72.² This work will also build confidence that other devices can be safely reprocessed, as has been the experience in site trials, where people have asked, ‘What about this or that device?’

In the mid- to longer term, undertaking further testing and analysis of the cleaning of devices using innovative equipment, to then subject them to UV-C for disinfection, rather than WDs or autoclaves, could go a long way to reducing power and water consumption across the NHS. Equally, looking at the option of sterilisation with UV-C would also prove beneficial from a capacity, cost, and environmental standpoint. Given the recent rapid advancements in LED UV-C technology, which are ongoing, and will improve along a similar trajectory to when fluorescent lights and normal light bulbs were replaced by LED lighting, is UV-C, certified to the appropriate standard, about to revolutionise decontamination, and — ultimately sterilisation?

References

1 Rizan C, Lillywhite R, Reed M, Bhutta MF. Minimizing carbon and financial costs of steam sterilization and packaging of reusable surgical instruments. Br J Surg 2022; 109(2):200-210.

2 Energy Trends and Prices statistical release: 22 December 2022. Department for Business, Energy & Industrial Strategy. https://tinyurl.com/yf56c5vr

3 In accordance with ISO15883 series.

4 As defined in the Spaulding scale.

5 BS8628-2022 — Disinfection using ultraviolet radiation. Methods for quantitative testing of automated ultraviolet disinfection activities by direct illumination. Determination of bactericidal, mycobactericidal, sporicidal, yeasticidal, fungicidal, virucidal and phagocidal activities. https://tinyurl.com/mw9he3dj

6 NHS Supply Chain FOI for 2023/24.

7 Eco Medic https://www.ecomedic.co.uk/

8 The Personal Protective Equipment at Work (Amendment) Regulations 2022. https://tinyurl.com/yfr9dxrv

9 Delivering a ‘Net Zero’ National Health Service. NHS England, 4 July 2022. https://tinyurl.com/2wbprwmz

10 NHS clinical waste strategy. NHS England, 7 March 2023. https://tinyurl.com/yfhasfyy