Purelight - Recent Press - Let there be light

Let there be light

By Andy Felton, Director, Purelight Europe Ltd.

With decontamination and prevention of HCAIs a growing issue for all healthcare providers, finding new and effective methods by which to clean and sterilise practices is at the front of mind for practitioners. New applications of UV-C light offer a clean, inexpensive and environmentally friendly way of rising to this challenge.

As bacteria and virus become increasingly impervious to traditional cleaning regimes, new sterilisation processes have to be adopted. Chemical sterilisation (Hydrogen Peroxide) has become more commonplace in the broader clinical environment, popularised by the proliferation of minimally invasive therapies, and the need for appropriate sterilisation protocols for the equipment used in these procedures. However, general-purpose units are still not available, and application usually requires the closure of the space for treatment. There are also concerns over levels of residual chemical. For this reason there has been an increasing interest in the application of ultraviolet light, or UV, as a chemical free sterilising solution.

The power of UV light to damage and destroy micro-organisms was first discovered in the 1870s. By the 1930’s it was known that specific frequencies of UV radiation had this effect, and by the 1950s, researchers understood the UV light penetrated cell walls and disrupted the nucleic acids (DNA and RNA) in microorganisms, preventing cell replication and repair, while causing mutations and the death of these organisms. This has led to the development of a range of applications for sterilisation that employ UV emitted at a higher frequency known as UV-C.

Although invisible to the human eye, given sufficient intensity, exposure and with professional, safe application, UV-C can kill most of the microbial life responsible for causing infection; this includes bacteria, virus, moulds, fungus, algae and the eggs of parasites. Within clinical environments the application of UV-C germicidal irradiation can now be easily applied as a low temperature, non-contact system for surface and air decontamination, sanitising without vapours or chemical residue.

Within the clinical environment there are three key methods for deploying UV-C sterilisation, direct surface application, passive environmental application and active environmental application.

The simplest and potentially most common deployment of UV-C within the clinic is also the most pro-active. Direct surface application of UV-C is delivered via either a fixed or portable UV-C source, in most cases this will be a lamp with an incorporated safety filter. The filter is important as these lamps will often be handheld by an operator for direct application to those surface ‘hotspots’ likely to create issues of cross infection. Instrument trays, reception and desk surfaces, sinks, telephones, and keyboards are all good examples of contact points requiring the application of regular sterilisation as part of an enhanced cleaning regime.

Within most situations, controlled application of 20-30 seconds of UV-C light will kill 99.7 percent of microbial life. A fixed lamp will guarantee sterilization within a short range (approximately 20 centimetres); the drawback of manual application across an area of surface however comes from the issue that UV light is of course invisible to the human eye, and treated surfaces will appear un-changed. This does mean application needs to be controlled and applied with a degree of professionalism, ideal when employed as part of a thorough cleaning regime. The advantages of these lamps are that they are safe, simple to use, chemical free and by far the most economic method for applying UV to assist in eliminating virus, bacteria, fungus, and parasites from visible, contact surfaces.

This is quite different from the ‘environmental application’ of UV. For large facilities with concerns of cross infection, a ‘passive’ application is a response to the threat of airborne contaminants, combining purification for the removal of dust, allergens and odour, with sterilization of bacteria and virus. Efficient and capable of delivering continuous and measurable environmental protection, this application of UV is particularly of value as a whole building solution. The most efficient installations will combine purification and sterilisation within a building’s air conditioning system. The disadvantage is that airflow within the A/C can be too high for as effective application of UV sterilisation, it is inflexible when it comes to reacting to a specific ‘hot room’ and installation has been prohibitively expensive.

These disadvantages have been addressed recently by advances in portable units that enable a more active environmental application, such as processing on an individual room basis. These portable units actively draw air through the purification and sterilisation matrices. Filters apply HEPA technology, exactly like a bagless vacuum cleaner, gradually slowing airflow through the devices and trapping contaminants within the latest, highly absorbent carbon and titanium dioxide filters, whereupon UV can be applied to sterilise and decompose microbial life.

The advantages of this approach are numerous, sterilisation rates remain high, at 98 percent plus, and the units are both affordable and highly portable, so can be swiftly deployed within a range of spaces, and critically, unlike chemical sterilisation treatments, can be used when staff and patients are in the room.

UV is already recognised and FDA approved for clinical sterilisation in the USA, and the European standard for Validation and Routine Control of Sterilization Processes continues to be developed within ISO TC 198. For the time being any UV-C device must demonstrate a CE rating, ensuring the device is proven and tested safe to use in the UK, before being considered for inclusion as part of an enhanced clinical cleaning regime. For any clinician with responsibility for infection control, the application of UV, whether reactive, or better still preventative, should be on the agenda as part of any regular cleaning programme with the practice, it is better for patients, it is better for staff.