Human containment reconsidered
12/01/2002
U.S. Army, hospitals evaluate Vickers box-like clean transport option
By Mark A. DeSorbo
BURR RIDGE, IL—IMAGINE A giant Ziploc sandwich bag big enough to package a person and outfitted with filters, intake and exhaust fans and sleeves that protect a patient and gives medical personnel access to that patient without the risk of exposure to contamination.
As odd as it may sound, the U.S. Army is testing the glovebox-like capsules, along with filtered body bags, that are designed for victims and fatalities of chemical or biological attacks.
According to Joseph Petrovic, president of Isovac Products, how to best move patients to established decontamination wards was the goal that drove the company to design the now patented "isolation apparatus."
With Army financing, Petrovic, along with inventors James Gauger and George Stefanek, developed the pod idea while they were researchers at the IIT Research Institute, a nonprofit research and development organization based in Chicago and McLean, VA. Robert Mullins, a fourth co-inventor, is still an employee of IIT Research.
The capsule, or pod, along with the filtered body bag, embody the British-made "Vickers box," a heavy, expensive piece of equipment used to transport Ebola and anthrax victims, as well as something known as a "desert wrap," which had a similar function during the Persian Gulf war.
While the Vickers box works, the Army, Petrovic says, wanted something that weighs 20 pounds, instead of 200 pounds, and something that was $5,000 instead of $20,000. Plus, the "desert wrap" was too much like a body bag, having just a small window to see patients, many of whom became claustrophobic.
"That's what we tried to achieve: the glovebox-effect," he adds. "We make it out of either polyvinyl chloride (PVC) or polyurethane. The PVC withstands chemical agents, but we also make it out of polyurethane because it is more durable and has better temperature tolerances."
In one embodiment, a tongue-and-groove zipper seals the pod—the same type found in plastic sandwich bags—while in another version, the capsule is sealed with an adhesive similar to that found on disposable diapers.
All the pods feature plastic sleeves that enable a health care worker to work on a patient without being exposed. The pods also have leak-proof ports for administering medicines or running respirators. Nylon ribs maintain the shape of the capsule so the plastic won't collapse on the patient.
"We build them so they can be positively or negatively pressurized and they have nuclear biological and chemical (NBC) filters, which go down to just a few microns so no biologic or chemicals can get through," Petrovic says.
The body bag, he adds, embraces the same concept as the capsule, except it is not transparent and is only equipped with a mechanism that combines an NBC filter and pressure release valve.
"On the body bag, we do put a NBC filter on it because as a body decomposes, gases are given off and pressure builds up in the bag; so we had to make sure that air could escape without releasing contamination."
While the new pods may be useful on the battlefield and in the event of a chemical or biological attack, they can also have many domestic uses, including protecting burn victims from infection or preventing the spread of infection from a bleeding patient who is HIV-positive.
"The other case is keeping an ambulance clean," Petrovic says. "If a person is shot and has HIV, the ambulance has to be taken out of service so it can be decontaminated."
While the Army continues to test the pods and the body bags, several versions of the two inventions have pending patent applications.
At some point, Petrovic says, Isovac will need to consider cleanroom manufacturing to ensure heat welds are not compromised by contamination. Presently, the capsules and the body bags are constructed with a series of heat welds at Woodstock Plastics (Marengo, IL).
The next step for Isovac is to build a portable environment that would provide the same type of protection as a cleanroom for use in mobile army surgical hospital (MASH) units.
And with the threat of biological and chemical attacks, the U.S. Air Force has placed an order with St. Louis, MO-based Engineered Support Systems Inc. for its field-deployable environmental control units (FDECUs).
The Air Force placed the expedited order for FDECUs under an existing contract to meet the military's urgent surge requirements, Michael F. Shanahan, Sr., Engineered Support's chairman and chief executive said in a statement.
The FDECU, he says, has become useful for most military units in remote areas where controlled air temperatures are required to include protection against chemical and biological agents.
The FDECU is used to cool, heat, dehumidify, filter and circulate air for portable shelters, hospital systems, tents and fixed sites to satisfy electrical and personnel climate control requirements. The current order requires that all units be delivered to the Air Force within one year to support its heightened military operations around the globe.
According to the Air Force, more than 10,000 FDECUs have been ordered to date under a multi-year contract, bringing the cumulative funded value of the contract to more than $116 million in total revenues.
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Isovac Products (Burr Ridge, IL) has developed a filtered capsule and a body bag that the U.S. Army is evaluating for use in the event of a chemical or biological attack. The capsule, according to the inventors, is also useful in transporting burn victims.