Using Technology to Stop Airborne Pathogens


John Pierson is manager of product development for Fiberlock Technologies, and shared with ICT the ins and outs of improving indoor air quality in healthcare settings.

Q: In an outbreak/pandemic scenario, what practices should automatically change to keep transmission of airborne infectious particles as low as possible?

A: The use of HEPA-filtered negative air machines, negative pressure anterooms and temporary containment units can greatly enhance a facilities ability to isolate potentially infectious patients. By giving a facility the flexibility to turn any standard room into a temporary isolation room, a hospital dramatically increases its ability to minimize airborne infections. The important thing to remember here is that pandemics, outbreaks and bio-terror events do not happen on a schedule and thus, a facility should have the ability to implement these countermeasures at a moment’s notice.

In the CDC Interim Guidelines on Smallpox, the CDC suggests that a facility or portion of a facility be set up to accommodate three segments of the populous: all contagious or probable infectious individuals, febrile patients without rash or other indicative symptoms and asymptomatic or vaccinated patients. In this guideline, isolation is defined as separation of a person or group of people to prevent the spread of infection. While most facilities have at least some level of fixed airborne infection isolation rooms, the chances are slim that they would have enough isolation rooms to facilitate the potential surge of a sudden outbreak and be able to accommodate these three potential segments safely.

Perhaps one of the biggest challenges a facility faces is the sudden influx of potentially infectious and critical patients. This surge of patients can prove to be an overwhelming force that can cripple any ER or outpatient clinic.

This is why the HRSA National Bio-Terrorism Hospital Preparedness Program states that all participating hospitals must have the ability to maintain, in negative pressure isolation, at least one suspected case of a highly infectious disease. It continues on to state that at least one facility in the region must have the ability to quickly isolate 10 patients within three hours post event (HRSA critical benchmark 2-2). Temporary containment units are an excellent way to meet these requirements and augment a facility’s ability to accommodate a sudden influx of patients.

Q: There are many ways that inside air can be protected from airborne pathogen transmission. What are some aspects that healthcare professionals can check right now to see if their systems are safe?

A: Most people in healthcare facilities are familiar with HEPA filtration as it relates to their building HVAC system, but at times less attention is paid to the portable negative pressure machines that are frequently used on a daily basis in the facility. These portable HEPA-filtered negative pressure machines are often used to control airflow and pressure differentials in rooms to create negative or positive pressure environments. They are also used with the portable containment units that most facilities are using now for dust control during maintenance.

In addition to adequate filtration devices like negative air machines, healthcare professionals should assess their physical inventories of critical equipment and supplies needed in the event of a pandemic like portable anterooms, disinfectants, masks, PPE and medication.

Q: Are there any errors you see time and again in hospitals that make patients and employees vulnerable to dangerous microbes?

A: The most common errors aren’t directly related to pandemics or outbreaks, but the common daily practices that have a far-reaching impact. The most glaring error is the lack of adequate dust containment and filtration during maintenance applications. Beyond the fact that dust is on its own a very dangerous airborne particulate, it also acts as an easy mode of transmission for other airborne pathogens. The dynamics that make dust good at staying airborne can also enable pathogens like Aspergillus, TB and SARS to further their range of impact. Pathogenic organisms can use this dust as a vehicle to remain airborne for far longer than they would be able to on their own. Hospitals can greatly reduce the impact of dust and the pathogens it carries by implementing the use of portable containment units with filtration into the ICRA process.

Secondly and more closely related to an outbreak situation is the fact that facilities simply do not have enough isolation rooms to accommodate the volume of patients that will likely fill the hospital waiting rooms. The idea of having hundreds of patients filling waiting rooms, triage rooms and patient rooms without some level of negative pressure isolation may be a huge and almost insurmountable problem that they will face unless adequate planning is done now.

Q: What type of training should healthcare professionals receive regarding how to keep air as safe as possible in the event of an outbreak or pandemic?

A: A good point of reference on airborne controls for preventing the transmission of airborne infectious pathogens is the CDC MMWR report ‘Transmission of Mycobacterium tuberculosis in Health-Care Facilities.’ This report gives very specific information on how to prevent the spread of droplet nuclei as well as how to reduce the concentration of droplet nuclei in a room.

Rooms used for TB isolation should be single-patient rooms with negative pressure relative to the corridor. The guidelines also recommend the use of negative-pressure enclosures that can be used to provide patient isolation in areas such as emergency rooms and medical testing and treatment areas to supplement isolation in designated isolation rooms.

Inside patient rooms, ASHRAE, AIA and HRSA recommend a minimum of six to 12 changes per hour. While the efficacy of reducing the level of droplet nuclei inside patient rooms has not been adequately evaluated, logic would dictate that a reduction in potential infectious agents would equate to a decrease in contagion.

While single occupancy might not be possible in the event of a pandemic outbreak, the same methodology of isolation by pressure differential is sound for any airborne pathogen. The fact that a pandemic or outbreak would be accompanied by a surge of infected patients only strengthens the CDC recommendation for alternative methods of patient isolation, like temporary anterooms, to augment the facility’s fixed isolation capacity.

Q: Which airborne pathogens are particularly adept at transmission, and what can be done about them?

A: Any organism given enough time to adapt can become extremely opportunistic, and that is at the core of the problem. It is difficult enough to prepare for an outbreak or pandemic with some level of warning like we had with H1N1—imagine the challenges we might face if another less common organism rises up to take the stage. For instance, genetic mutations in an organism like Yersinia Pestis could decrease the efficacy of standard antibiotics. This has been seen only once in a remote case of plague in Madagascar, but it shows that the potential is there.

Perhaps even more disturbing is the possibility of mutations in any of the viral hemorrhagic fevers like Ebola, Marburg virus or Lassa fever. These organisms in their current form are highly contagious and deadly, but due to the fact that contagion is dependant upon close contact and that there is a short window of opportunity between a vector becoming infectious and the onset of symptoms, it is easily identified and contained. If either of these factors were to change even slightly, the risk of hemorrhagic fever becoming a pandemic could rise exponentially.

In 2003, healthcare professionals saw what could have been the birth of a global pandemic in SARS. It was highly contagious and had a substantial rate of morbidity, but was contained by local and international health authorities before it could spread. This disease has not been eradicated, so there is a good possibility it will return.

For all of these organisms the same defense holds true, open communication between international communities and diligent surveillance on a local level is critical to getting in front of a potential outbreak. If each healthcare facility is quick to report trends of infection or new developments in drug resistance to the appropriate authorities like CDC, they stand a strong chance of stopping pandemics before they start.

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