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Working for the Warfighter: Testing of Biocontainment Units for Transport of COVID-19 Patients

Working for the Warfighter: Testing of Biocontainment Units for Transport of COVID-19 Patients

By Jana Kesavan

COVID-19 has changed our lives. U.S. citizens residing outside of the U.S. face the problem of getting adequate medical care in the countries they live in when they get infected with the SARS-COV-2 virus that causes COVID-19. The U.S. government is transporting COVID-19 patients to hospitals for medical care if adequate medical care is not available in the countries the patients reside in.

Biocontainment units are infectious disease containment units designed to transport patients while providing medical care. These units are also designed to protect the aircrew, medical attendants and the airframe from getting exposed to infectious organisms. In addition, these units must be tested before fielding to confirm their function.

Recently, the Sensors Signatures and Aerosol Technologies Branch at the Combat Capabilities Development Command Chemical Biological Center (DEVCOM CBC) supported biocontainment unit testing at Joint Base Charleston, South Carolina. From March to June 2020, I travelled multiple times to Joint Base Charleston to participate in the testing of two fielded units and two new units.

The first type of biocontainment unit was developed after the Ebola crises in 2014 to transport infected patients. This unit is called the Transport Isolation System, or TIS, and was constructed with metal frames lined with clear plastic walls. This design allows for the walls to be removed and discarded after each transport. The next biocontainment unit used to transport Ebola patients was built for the Department of State in 2015 and is called the Portable Bio-Containment Care Module, or PBCM. Unlike the TIS, the PBCM is a solid walled unit.

The Negatively Pressurized Conex, or NPC, is the first new unit built and delivered to the U.S. Air Force’s Air Mobility Command at the end of April 2020 to transport COVID-19 patients. Another smaller unit, called the NPC-lite, was also built and delivered to the Air Mobility Command in May 2020 for use with smaller planes, such as C130, transporting COVID-19 patients. All biocontainment units are separated into a patient room and an anteroom. Personal protective equipment is donned and doffed in the anteroom. In addition, the PBCM has a staff room for resting.

In general, biocontainment units need to maintain negative pressure, adequate air exchanges and biocontainment during various activities such as blower malfunction, health care worker entry and exit to the anteroom and deplaning. The negative pressure is maintained by one or two blowers pulling air from the far end of the patient room. This allows high-efficiency particulate air (HEPA) filtered air to enter the staff room, then the anteroom and then the patient room. HEPA filters are also placed between the rooms to prevent any aerosol from entering the anteroom if negative pressure is lost. In addition, these units need to be secured to the aircraft and should not produce electromagnetic interferons to affect the function of the aircraft.

An operational utility evaluation is conducted by practicing patient care and deplane activities on the ground and in air. Aerosols need to be contained during various patient care activities, movement of health care workers into the anteroom and during deplaning. Various decontamination solutions and methods were also tested during this time.

The Defense Threat Reduction Agency (DTRA), Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense (JPEO-CBRND) and Air Force Life Cycle Management Center provided the funding for SSAT’s support of the biocontainment unit testing at Joint Base Charleston under the Joint Urgent Operational Need testing event. Many agencies and universities participated in the tests to determine the negative pressure, filter efficiency, air exchange rate, aerosol purge rate, biocontainment efficiency and decontamination efficiency. The testing of these biocontainment units was truly a team effort, and I learned a lot  from interacting with the many groups that supported the test, such as the Air Force test group, health care providers, Clarkson University, Public Health Center, DTRA and the JPEO-CBRND. I was able to interact with Aeromedical Evacuation Airmen and influenced key decisions with Army Materiel Command’s COVID-19 patient movement plan.

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▲ Jana Kesavan, Ph.D. is a research physicist at the U.S. Army Combat Capabilities Development Command Chemical Biological Center. She received her Bachelor of Science in biomedical engineering, Master of Health Science and Ph.D. in environmental health sciences from the Johns Hopkins University. After one year of post-doctoral fellowship at the Johns Hopkins University School of Medicine and one year of National Research Council fellowship at the U.S. Army, she started working for the Center. She has more than 20 years of aerosol related experience and is managing an advanced laboratory for aerosol research on chemical and biological defense.