Given the proliferation of difficult-to-eradicate superbugs in medical environments such as hospitals, doctors are increasingly concerned with finding ways to reduce or eliminate the spread of contaminating organisms. Their concern is warranted; research has shown that microorganisms such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococcus and gram negative bacteria can survive on inanimate objects such as hospital equipment and computer keyboards for many months.1,2 Furthermore, even clean hands touching these objects can pass them along to other objects and people.3,4
According to the Centers for Disease Control and Prevention, nosocomial infections may account for as many as 80,000 deaths in the United States each year.5,6
Given this reality, doctors concerned about patient health and medical liability have increasingly come to rely on single-use surgical instruments to reduce the likelihood of infection. Furthermore, this idea has been extended to "noncritical" tools—items that contact a patient's skin but not mucous membranes—such as pulse oximeter sensors.
One reason for this is that manual disinfection of noncritical equipment often fails to eliminate microorganisms.
Unfortunately, using disposable tools comes with a very large price tag. A mid-size hospital may use as many as 30,000 disposable pulse oximeter sensors per year at a cost of up to $15 per unit. Multiply this by thousands of hospitals and ambulatory surgery centers. Then, consider how many other disposable instruments are routinely being used and thrown away in those establishments. Without a doubt, the cost to our medical system runs into billions of dollars. And the manufacture and disposal of all these tools comes with a huge environmental cost as well.
A Farewell to Organisms
Today, however, a new alternative is on the horizon. A multi-disciplinary team at Johns Hopkins has developed a simple but effective device that can quickly decontaminate noncritical medical equipment of all shapes and sizes. The seven-foot-tall box, which resembles an enclosed shower cubicle, has been dubbed the "self-cleaning unit for the decontamination of small instruments," or SUDS.
SUDS works by aerosolizing a disinfecting agent and fogging whatever items you place inside it, effectively dispersing the disinfectant over the items' entire surface area. The device can use any disinfectant that can be aerosolized, such as Sporicidin (a commercially available disinfectant) or bleach. That flexibility has the advantage of allowing you to switch disinfectants if you encounter bacterial resistance. The SUDS device takes about 30 minutes to disinfect medical equipment of all shapes and sizes, including IV poles, blood pressure cuffs, electrocardiogram wires, computer keyboards and pulse oximeters. (Electrical equipment appears to be unharmed by the process.) The device is also self-cleaning, using other modalities such as ultraviolet light and dry heat.
These were originally included in case fogging with disinfectant failed to sufficiently eliminate organisms from treated items, but research showed that fogging by itself was highly effective.
In the first clinical study of the device, portable medical equipment such as pulse oximeter sensors, IV poles and blood pressure cuffs were decontaminated either manually or using the SUDS device. After manual decontamination, 23 of 91 tools (25 percent) were found to be culture-positive with clinically significant microorganisms. In contrast, after decontamination using SUDS, zero organisms were detected, and cultures taken after 48 hours—even with the tools back in clinical use—still found zero contamination.7
Building a Better Mousetrap
Bolanle Asiyanbola, MD, MRCS, surgeon, assistant professor at Johns Hopkins and co-author of the most recent study of the SUDS device, is credited with the original concept and design. Dr. Asiyanbola says she came up with the idea for the device after seeing patients in the emergency room, where decontamination is far more difficult than it is in the average operating arena. "In the ER, for example, IV poles are switched around constantly," she says. "There's no mark on the poles, so there's no way to track where they've been or whether they've been contaminated. In fact, we found that 25 percent of the medical equipment we tested was contaminated by clinically significant organisms such as MRSA and VRE.
"It occurred to me that fogging these instruments inside a container might be an effective way to decontaminate them," she explains. "When I tried it, it worked beautifully. Among other things, this approach has the advantage of ensuring consistency of the decontamination process, while only requiring the use of readily available disinfectants."
SUDS could have a significant impact on the cost of medical care by reducing the perceived need to use so much disposable equipment. "Ironically, there are no peer-reviewed, large studies showing that disposable tools such as pulse oximeter sensors actually prevent infection or lower infection rates," she notes. "Even more worrisome, there are no cost-effectiveness studies. I think it's safe to say that single-use tools are one of the biggest reasons for the high cost of medicine in the
Dr. Asiyanbola admits that the device in its current form has some limitations. "SUDS is not usable for sterilizing items such as surgical tools," she says. "Most of the disinfectants used in SUDS are not intended to produce total sterilization." And she acknowledges that the process could be leaving a fine disinfection residue on the treated items—which would explain instruments remaining germ-free even after two days of post-disinfection use. However, she notes that this is no different from the residue that you get when you manually wipe the equipment down.
Dr. Asiyanbola also points out that some items are too big even for the SUDS device to disinfect, but she doesn't see that as a problem. "If the person cleaning up can put multiple items in the SUDS box, that person will have a lot more time to work on disinfecting other items that are too big to put in the box, such as beds," she says.
In terms of getting SUDS to the marketplace, patents are pending, and Dr. Asiyanbola hopes to see a commercially available version of the SUDS device within two years. She says the team's intention is to make this technology as inexpensive as possible. "I've been on the front lines; I've taken care of patients who have no insurance," she says. "I know how important it is to reduce costs."
In the meantime, the team is planning to conduct another clinical trial. Goals may include determining how effective SUDS is against specific superbugs such as Clostridium difficile.
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