The microbes that hide in nooks and crannies of medical instruments nearly killed a momentous advance in sterilization technology.
Scientists at Advanced Sterilization Products had sworn to abandon their new sterilization system if it couldn't wipe out bugs in hard-to-reach places. Two weeks from a self-imposed deadline, they found their answer in a small vial of common hydrogen peroxide.
Sterilizing troublesome spots, like the hollow tube of an endoscope, is one of several challenges overcome in ASP's 12-year quest to build its new technology.
Today, ASP's Sterrad system is among a handful of new technologies in a potentially booming market. At year-end, federal law will ban CFCs, or chlorofluorocarbons, a common component in traditional ethylene oxide sterilization, and hospitals will need alternatives (See story, this page).
"It seemed to be an area screaming for new technologies," said Tralance Addy, vice president and general manager of Irvine, Calif.-based ASP, a Johnson & Johnson division. "We were going to develop technology that had a big impact or give up. We came within two weeks of (giving up). But if we could crack the problem, we had a major innovation."
The Sterrad saga began in 1981, a few years after regulators declared ethylene oxide (EtO) a carcinogen. Johnson & Johnson had lured Addy from a paper manufacturer to head a new research arm. Then, as now, most hospitals used EtO, diluted with CFCs, to sterilize heat- and water-sensitive equipment in a 12- to 16-hour cycle so toxic byproducts dissipate.
"We were faced with a paradox," Addy said. "An ideal sterilization system has to be fast; it has to be low in toxicity; it has to be kind to a wide variety of instruments. But things that are toxic to micro-organisms are most likely toxic to human beings."
Borrowing from NASA research, Addy's group turned to plasma, the fourth state of matter. In a vacuum, electromagnetic fields will convert gas into a cloud of ions, electrons and free radicals that attack micro-organisms. Hydrogen peroxide is a particularly effective base because it turns into plasma at temperatures that won't damage delicate instruments. At the end of an hourlong sterilization cycle, it recombines into nontoxic elements, such as oxygen and water.
Perfect as it sounds, the nature of plasma nearly stood in the way. Hospitals sterilize medical supplies in packaging so they can keep them sterile until use. Water vapor or gas will seep through the small pores in packaging, but the elements of plasma won't. Because they're so unstable, they'll return to their previous state when they hit a barrier and won't be a good weapon against microbes.
Addy's group, suffering what it labeled "theory of the week" syndrome, struggled against reality for a year. After several failures, researchers discovered the theory that worked in practice. If they created an electromagnetic field later in the sterilization cycle, plasma would form within the packaging after hydrogen peroxide gas had suffused it.
That was 1984. The next year proved critical. Not enough gas reached the long, hollow tubes of some instruments for effective sterilization. Frustrated, the group nearly gave up. Under deadline, they discovered an innovative solution. If they attached a vial of hydrogen peroxide, an "adapter," to the end of the tube, it would direct gas inside.
In concept, their system was complete. In 1987, the company asked the Food and Drug Administration for approval to market the product. Regulators took six years to grapple with the invention. The adapter still is under review, but ASP anticipates approval later this year.
"We had set out a target that we would have a sterilizer that was different from any before," Addy said. "I think learning about the change, people found it incredible. It almost sounded too good to be true.