INFECTION PREVENTION AND CONTROL The missing link: Air disinfection
Inactivating viable airborne particles before they settle on surfaces can provide additional protection against infections.
Dozens of strategies show promise for improving hand hygiene. Among them: rewarding healthcare workers for better compliance, electronic monitoring of hygiene practices, and presenting healthcare workers with real-life, personal stories demonstrating the human cost of hospital acquired infections. The solutions for halting surface transmission are varied, too, and include placing more patients in single rooms,51 installing copper bed rails,52
dispatching
dedicated cleaning teams to high risk areas, applying fluorescent products to surfaces for better oversight, and shifting to single-use EKG leads, blood pressure cuffs, and other devices for patients with poor skin integrity. But these and other strategies are costly, subject to red tape, and unlikely to make an immediate impact on infection rates. As one research team noted, “Improving hand hygiene involves changing a habit, and it takes time to obtain a sustained improvement.”
It also takes time – about a decade – to develop new antibiotics. Already, 70% of bacteria have developed resistance to antibiotics;53
when one superbug is
vanquished, two new superbugs surface. Hospitals don’t have the luxury of time or unlimited budgets. As healthcare facilities work toward improved hand hygiene, surface control, and antibiotic management, Prof Assadian observed: “There is a very strong argument to also think about additional options.”
One of the most encouraging options is using air disinfection to inactivate potentially dangerous particles before they settle on surfaces and colonise filters. It is impossible to know what percentage of hospital acquired infections are transmitted through the air, but “strong and sufficient evidence” implicates airborne spread of pathogens – MRSA, Acinetobacter, Clostridium difficile, influenza, and norovirus among them - in the current crisis.54, 55
“Airborne transmission of
infectious disease,” one research team noted, “is a major public health concern.”56 Vomiting, coughing, even talking can release infectious microbes into the air. Conversation in the operating room can increase the bacterial load of air and
In most cases, it is simply impossible to separate infected patients from vulnerable patients. That’s why it is important to disinfect the air they share.
contaminate the facemasks of surgeons and nurses; the greater the crowd in the OR, one study found, the greater number of microspheres detected in a simulated wound.57 Mere breathing can release infectious microbes into the air. An American study found medical providers within six feet of influenza-infected patients can be exposed to infectious doses of the virus.58
particles can waft in the air for hours and travel long distances via air currents, while larger particles settle on surfaces. A single infected patient walking to a hallway bathroom can pose a significant threat. Pathogens are not just propelled into the air by sick patients; they are also carried into hospitals on the clothing and bodies of visitors and staff and swept via air currents into emergency entrances, lobbies, corridors, stairwells, and patient rooms.
Measure such as bed spacing, patient
isolation, and promotion of patient cough etiquette can only do so much to minimise the airborne spread of infectious microbes. Not only do few hospital wards have enough rooms to accommodate all infected patients, but staff tend to prop doors open so they can more easily monitor isolated patients.59 In most cases, it is simply impossible to separate infected patients from vulnerable patients. That’s why it is important to disinfect the air they share. Appreciating this reality, hospitals deploy air ventilation, filtration, and sanitisation solutions. But all of these approaches have limitations. Ventilation systems must be well maintained to achieve and sustain the required air-change rate, but when maintenance lags – when filters clog or ducts leak – the result is a build-up of the very pathogens these systems were designed to remove. “Poorly maintained ventilation systems may eventually act as a source of, rather than a defence against, aerosol/airborne infection,” concluded a University College London study.60
Attaining uniform airflow Smaller, lighter
To attain uniform airflow is also a challenge. Consider a large ICU that could be the size of a basketball gym. Air flow through the unit is rarely constant, due to the uneven placement of vents and the way beds are partitioned. Movement of staff, visitors, access doors, and privacy curtains also can influence air currents, dispersing pathogen-bearing particles throughout the space. Even common areas require careful attention to airflow. As one research team noted, ventilation in communal areas such as cafeterias and corridors plays “an important role in maintaining a steady exchange of clean air for potentially contaminated air.”61
HEPA
filtration is often thought of as the gold standard in air purification, but filters only trap pathogens; they don’t kill them. Viable pathogens caught in a HEPA filter can colonise, presenting a safety hazard for maintenance staff who are handling the filters and others who may be exposed during the disposal process. Aggressive air-sanitisation methods such as UV can promote the formation of cataracts and other eye conditions,62
while misting
hydrogen peroxide can irritate or burn the skin and corrode surfaces and instruments. What’s more, the sanitisation effect of these “point-in-time” solutions is temporary; bioburden multiplies as soon as people begin introducing bacteria and pathogens from hallways, common areas, and the outdoors. But effective air disinfection need not involve chemicals. An alternate strategy – one that operates continuously - deploys ultra-low energy plasma technology to destroy airborne pathogens on contact. The technology is safe for continuous use around vulnerable patients and staff and is proven to destroy airborne pathogens on contact. This solution can be easily mobilised in high risk situations like surgeries or operated continuously in large patient wards, ICUs, emergency rooms, and IVF labs. For numerous European hospitals, ultra low-energy plasma technology has become an effective weapon in the fight against healthcare acquired infections, augmenting hand hygiene, surface cleaning, air ventilation, filtration, and sanitisation. As infections become more difficult to treat, healthcare facilities must work to destroy pathogens before they colonise filters or land on the lab coats, surgical gloves, bed rails, and other surfaces that serve as conveyor belts for infection.
References for this article are available upon request.
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