PIU
THE AIR FORCE WRAPS UP PATIENT ISOLATION UNITS.
The U.S. Air Force 77th Aeronautical Systems Group (77 AESG/PSK), based at Brooks City-Base, Texas, recently collected long-anticipated bids to provide Air Mobility Command with patient isolation units (PIUs) for the care and evacuation of injured or sick soldiers from the battlefield. In its request for proposals, 77 AESG/PSK finalized the performance specifications for the PIU—a mobile bed intended to safekeep soldiers struck by chemical or biological agents. The Air Force, naturally, would like these units to fit on a variety of airframes used for aeromedical evacuations.
According to the Air Force, “The purpose of the PIU is to isolate contagious patients during aeromedical evacuation onboard Air Force C-5, C-9, C-12, C-17, C-21, C-130, C-130J, KC-135, CRAF-767, KC-10, and the UH-60 and CH-47 helicopters.”
In creating a unit that could transport such patients, manufacturers were required to adhere to meet or exceed Biological Safety Level 4 filtration specifications from the Occupational Safety and Health Administration and the Centers for Disease Control. PIUs also must meet or exceed Class II medical device requirements from FDA. From a functional standpoint, the PIUs must actually fit onboard the range of specified USAF aircraft and integrate with existing medical equipment. The maximum allowable length of the PIU is 91.6 inches and width is 22.38 inches. The unit must maintain a minimum clearance of 12 inches between a patient’s face and the interior surface of the unit.
In addition, the PIU and its components should “have finishes that can withstand the environments and operational use over its service life,” according to the Air Force. “Protective coatings and finishes shall not crack, chip, or scale during normal operational life or in the specified extremes of environmental conditions.”
PROTECTING LIFE AND INVESTMENTS
Perhaps the largest of the companies interested in securing the PIU contract is Gentex Corp., headquartered in Zeeland, Mich. John Pullo, Gentex, vice president and general manager, told MMT that his company has been developing chemical and biological materials for more than 25 years and has been working on the PIU since the 1990s.
“It’s not only a means of isolating the patient from others but also a means of safely transporting the patient to another facility,” explained Pullo. “It’s for the patient’s care as well as to protect the health care workers—the aeromedical personnel, for example, who might come into contact with the patient during their care until they can reach a medical facility.”
But the PIU also must protect USAF equipment from contamination that could spread from surfaces to other people as well as destroy expensive electronics. “The last thing you want to do is contaminate the aircraft,” Pullo said. “The decontamination steps that the Air Force or some other service must go through to decontaminate an aircraft or vehicle given that there may be sensitive electronic equipment in that aircraft is very expensive, could damage the equipment, and requires the equipment to be taken out of service during the time it’s being decontaminated. So it’s very costly and very disruptive to operations.”
Pullo noted that in order for the PIU to fit the aircraft platforms that must transport it, racking systems that interface with specific fixed wing or rotary wing aircraft have been developed in the past. These racking systems and transport systems enable the PIU to travel onboard the required range of aircraft. As PIUs evolve, the units and their racking systems must support interfaces with medical equipment.
“One is the need to provide patient care at levels that are higher than just simple transport,” Pullo said. “That is providing interfaces with highly specialized life support equipment, life sustaining equipment, things of that nature, and also sensing and monitoring equipment that could be interfaced appropriately with patient isolation units. So while the base unit may or may not have these functionalities built in, certainly the interfaces for them need to be built in.”
Gentex plans to focus on making its Casualty Care System PIU units lighter, more durable, and more affordable for large-scale production in the future. The focus on package size and weight would make the mass transport of PIUs to the field easier, Pullo observed. And lowering the cost of mass produced PIUs would make them more appealing to Air Force contract officers responsible for procuring them.
But these innovations could also impact medical communities outside of the military.
“It became clear to us during the work that we did for the military that the concept of isolating infected patients, for example, would have broad appeal for disaster recovery or relief, as the case may be, relating to the need to move patients that were infected with contagious diseases like Ebola or something along that level, which would provide protection for the medical workers as well as permit safe transport of the casualty,” Pullo said.
“Clearly, in addition to the military application, applications might involve operations for the World Health Organization, the CDC, the Department of Homeland Security and on and on, any arena that might involve the need to care for large numbers of casualties and isolate them from the rest of the population may have high utility in this case,” he concluded.
Gentex does not go it alone, however. Its alliance with Halo-Source Inc. of Redmond, Wash., provides Gentex products with a halogen-binding process that fights the spread of microbes.
“Our particular technology is a treatment for a textile or a surface that places sockets onto the textile or the surface that allows the surface or the textile to bond with chlorine ions. Therefore, the textile or surface takes on the same oxidative properties and anti-microbial properties as chlorine,” Dave Kowalick, director of business development for HaloShield at HaloSource, told MMT.
The HaloShield coating binds chlorine or bromine at the molecular level, Kowalick noted. The result is that the surface or textile in question gains the power to oxidize microbes without any free chlorine or bromine lying around. “So now the halogen is stabilized on the surface, and when it comes in contact with a microbe or a toxic industrial compound, it is able to oxidize that compound or that microbe or that pathogen. Once it does that, the chlorine is used up. With our technology, once that chlorine has been used up, you can recharge the surface again with a bromine or chlorine solution,” Kowalick said.
The HaloShield-coated surface of simple textile materials like bed sheets or lab coats can recharge through a simple washing with commercial laundry detergent. The anti-microbial barrier has a kill rate that is measured in hours, ensuring its efficacy for protecting a patient from exposure to microbes or protecting the patient’s environment from exposure to any of his germs. As such, it is much more effective than many other anti-microbial treatments.
“Silver is a well-known anti-microbial compound,” Kowalick remarked. “You can impress silver into a textile or place it on a surface. Silver is known to work but it has a very slow kill rate. The kill rates are measures in days with metals. With ours because it is a halogen, you get that incredible killing power of the halogen, which is so much greater than other things.”
“An ammonium compound kills in hours,” he added, “That stays on the fabric, but it reduces over time. You can always recharge the coating back to its original chlorine loading with ours, which makes it somewhat unique.” The high kill rate and the recharging ability make halogen-based solutions attractive for military applications, where exposure to microbes could make an injured patient sicker and where time may not permit lengthy recoating processes.
BIOTERRORISM THREAT
ISOVAC Products LLC, based in Romeoville, Ill., has been working on its CAPSULS PIU for about seven years, according to Joseph Petrovic president of ISOVAC. “Until recently, there were no devices available that were compatible with current mass evacuation procedures and equipment,” Petrovic said. “Without devices for isolation there is a very high risk of contaminating emergency first responders, other emergency personnel, evacuation equipment and assets, and other safe-haven environments such as trauma centers and hospitals.”
PIUs are able to transport infectious patients or those with compromised immune systems. The patients can be held in a negative pressure mode or a positive pressure mode, Petrovic explained. In a negative pressure mode, a blower draws air from inside the PIU and filters it then returns it to the environment outside of the PIU.
“This isolation mode protects first responders or caregivers from getting contaminated by the patient,” he described. “For scenarios where the patient is not contaminated, but there is a threat of transporting the patient through a potentially contaminated area, the PIU will operate in a positive pressure mode. In the positive pressure mode, filtered air is blown into the PIU to provide clean air from a contaminated, external environment.”
The CAPSULS 2004 has received clearance from the FDA as a Class II medical device, according to the company. The PIU has a clear plastic enclosure with multiple access ports for use by medical personnel. It mounts to a standard NATO litter and provides HEPA-filtered air. The CAPSULS unit also operates and maintains flexibility in both arctic and desert conditions.
The unit opens much like a suitcase, allowing easy setup and loading of a patient in about 10 minutes or less. The air blower inside of the PIU uses a single battery, which can operate for up to 10 hours and has a shelf life of 10 years. “Even though the concept of the patient isolator has been around for many years with many patents for a variety of different concepts, it isn’t until recently with the threat of bioterrorism and outbreaks that the need for a relatively low cost, lightweight and easy-to-use unit has become apparent,” Petrovic noted.
In the future, medical personnel are likely to see innovations such as the addition of features that enable the heating and cooling of patients that need to be transported in extreme conditions, additional monitoring devices for differential pressure, interior/ exterior temperature, continuous pass-through ports, and materials and processes that would continually decrease the cost of the units, Petrovic added. ♦