Ventilation play an important role in maintaining a steady exchange of clean air in hospitals. However, when a large number of people move through open spaces in hospitals, with their infectious status unknown, a normal airflow approach to aerosol infection control is not sufficient to control airborne contaminants from spreading.
Cold plasma technology = advanced electric filtration technology
In order to stop the contaminants from spreading, the route of transmissions has to be known
Nosocomial disease can be transmitted by air, over large distances, by direct or indirect contact, or a combination of both routes. The transmission pathways for hospital acquired infections are generally divided into three categories: personal measures, administrative controls and engineering controls.
Personal and administrative controls are intertwined as the former cannot be controlled without the latter. Personal measures are instructed to patients, visitors and staff, and can include a variety of measures, including hand washing, the wearing of masks, removal of jewellery, reduced physical contact (such as hand shaking). Engineering control methods include building ventilation, use of HEPA and other air cleaning methods. Ventilation refers to the supply of outdoor air into a building, and its circulation in the building.
The effectiveness of ventilation is important for controlling airborne diseases
If a disease can be shown to be airborne, the importance of filtration becomes obvious. While contact transmission of disease forms the majority of HAI cases, transmission through the air is harder to control, but it is the problem, where effective air decontamination plays an important role in limiting the spread.
There are two basic physical principles behind the roles of ventilation in infection control. The first is through dilution of airborne pathogens, and the second is the control of movement of airborne pathogens from one space to another.
Building ventilation has three basic elements:
- ventilation rate; the amount and the quality of outdoor air that is provided into the space
- airflow direction; the overall airflow direction in a building, which should be from clean zones to dirty zones
- air distribution or airflow pattern; the external air should be delivered to each part of the space in an efficient manner and the airborne pollutants generated in each part of the space should also be removed
The benefit of electric filtration is the ability to collect and eliminate living microbes – unlike HEPA.
Additional air contamination control by corona discharge – to remove particles from an aerosol
Varying standards define what qualifies as a HEPA filter. The two most common standards require that an air filter must remove (from the air that passes through) 99.95% (European Standard) or 99.97% (ASME standard) of particles that have a size greater than or equal to 0.3 µm. HEPA standard was commercialized in the 1950’s. Nowadays, much smaller particles can be measured, and the need for additional air decontamination has been identified.
Advanced Electric Filtration Technology (=Cold Plasma Technology) can be used to complement ventilation for airborne infection control in hospitals. The benefit of electric filtration is the ability to collect and eliminate living microbes – unlike HEPA. The technology has the ability to collect contaminants of all sizes. It is usually a flexible and mobile additional solution for hospitals, where a varying amount of clean rooms are needed, as the ISO-class 5–7 can be reached within 10 minutes.
Reducing the cost of hospital acquired infections
It becomes obvious, that it should be defined, what are the roles of ventilation methods in hospitals. It doesn’t only save lives but can also remarkably reduce the cost of patient care. Linked to that conversation, it should be understood, how the ventilation requirements for infection control differ from comfort and general health requirements. What should be the ventilation requirements for airborne infection control, and what other measures should be collectively applied to remediate transmission of nosocomial infections. More research is needed over the next years, to understand better the sources of contaminants, and their pathways through large open spaces carried around by people.
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