Spare a thought for the unfortunate patients of Yeovil Hospital wards 7B and 8B. With the two wards hit by a nasty Norovirus outbreak, Director of Nursing Shelagh Meldrum is proposing to eliminate the germs WITHOUT the use of bleach or other “harmful chemicals” (i.e. disinfectant). Instead, she will put her trust (and her patient’s lives) into the hands of the notorious fake medical equipment company, Hygiene Solutions Ltd of King’s Lynn.
The Ultra-V sounds like something from science fiction. Unfortunately, that is exactly what it is. A cheaply reverse-engineered copy of an obsolete American device, built in the back of a farm sundries warehouse, the Ultra-V is foisted on unsuspecting NHS by unctuous salesmen armed with a pack of outrageous lies, which can be disproved by anyone with a basic understanding of physics.
UV-C light, as generated by the Ultra-V is well known for its germicidal properties. So what exactly is the problem with the Ultra-V, and why should the hospital not use this instead of bleach?
The problem is that light travels in straight lines, and hence casts shadows. This is very evident from the photo of a crescent moon above. The dark side is very dark indeed, the sunlight does NOT wrap around corners to light up the lunar night. This is just as true for UV light as for any other wavelength. Otherwise you could get a suntan at night.
Shadowed areas in a hospital room are not exposed to the UV radiation, hence are not disinfected. Conventional UV-C systems deal with the problem by using two or three light emitting units placed around the room to eliminate the shadowed areas, or otherwise require the unit to perform two disinfection cycles from two different locations in the room, thus ensuring that all areas are exposed at least once.
According to their sales brochure, the Ultra-V, by some miracle of optical technology can reach “shadowed areas, under bedside units and hidden corners” all from “one central location within each room”.
This miracle is achieved by “Spectromes”. These are apparently small light meters that are placed around the room to ensure that all surfaces get fully exposed. The exposure time is theoretically extended until the darkest “Spectrome” has had a full dose.
The only UV light received by a Spectrome that is in a shadow is the diffuse reflections from the lit surfaces of the room. Unfortunately most substances absorb UV-C radiation very strongly – far more than they do for visible light. In the UV-C world, almost everything non-metallic looks black.
Typical hospital surfaces absorb 95% of UV-C radiation, and scatter the rest. It follows that the shadowed areas are very dark, as at the most they can expect to receive 1/20th of the radiation of the directly lit areas. Consequently, if this scattered light is to disinfect the shadows, the process will have to be extended in duration 20 fold. Is this what happens?
The normal process time with the Spectromes fully exposed is 15 to 20 minutes. Place a Spectrome in the shadows, and the process might extend to 40 minutes at the max. (Try it, if you don’t believe me.) At this point, the Ultra-V is programmed to override the Spectrome, and turn out the UV lights, indicating that the process is complete. Just in case hospital staff might be suspicious, the Ultra-V automatically sends a cheerful email to the operator’s designated address, giving time, date location, and certifying that the room has been decontaminated to a log 4 to 6 standard.
To give an example of how dangerous this is, consider the bedrails on a standard hospital bed – these are high touch areas constantly exposed to the patient’s hands and every cough and sneeze. From its “single central location” the Ultra-V unit, obviously and indisputably will only illuminate one side of each bed rail. The other side will be nearly as dark, in UV terms, as the dark side of the moon in the photo above. A standard Ultra-V process will leave these areas highly contaminated. A simple test with standard Biological Indicator coupons will prove this. (Again, don’t take my word for it – try it.)
To compound the error, the Spectromes are narrow bottomed plastic boxes that have to be placed on a hard, level surface, usually the floor or a bedside cabinet. it is completely impossible for them to monitor small, high touch areas like the back of a bedrail.
So on the positive side, at least the unshadowed areas will get a thorough log 4 to log 6 clean? Sadly not. The following Journal of Hospital Infection article detailing a study at the Wye Valley NHS Trust, demonstrated an efficacy of less than log 1 for the Ultra-V.
The outlook for the patients of Yeovil hospital does not look very bright, at any wavelength, unless there is a change of heart.
Please Shelagh Meldrum, for the sake of both patients and staff, don’t throw away the bleach just yet…use your £50,000 white elephant if you must, but give the wards a good old-fashioned hypochlorite deep clean first!