One technology that has become an increasing presence in hospital settings over the last 10 to 15 years is the use of ultraviolet (UV) light to help sanitize those facilities to reduce the risk of health care-acquired infections. And both the Department of Veterans Affairs (VA) and U.S. military medical systems have become leaders in the application of that technology to help protect patients and improve their medical care.
“Our scientists have been looking at the factors that lead to infection transmission within the hospital settings, what we call health care-acquired infections or nosocomial infections,” explained Chetan Jinadatha, MD, MPH, chief of the Infectious Diseases Section at Central Texas Veterans Health Care System, “and they can be lumped into two broad categories. One is what we call device-related infection, and examples could be infections resulting from a catheter or throat tube. The second major category are non-device infections, which are further broken down into surgical site infections that are process related and MRSA [Methicillinresistant Staphylococcus aureus] and C. diff. [Clostridium difficile] infections. And the majority of the infections in the hospital are in these two categories: Either they are MRSA, with or without device, or Clostridium difficile infections.”
Jinadatha added that researchers attribute approximately half of these infections to contamination that is around the patient’s room.
“For example, let’s say you are a patient who comes into the hospital for chest pain, and you get admitted to a room that was previously occupied by a MRSA patient. You are two to three times more likely to get a MRSA infection as compared to somebody going into a non-MRSA previously occupied room. And it’s a similar number for some bacteria and some viruses. So what we found out is that the surfaces in the hospital rooms are grossly contaminated when occupied by a patient carrying the disease.”
He was quick to clarify that housekeeping staffs are extremely dedicated and apply their best efforts to cleaning rooms after patients are discharged, but added that some residue or contamination can be left on surfaces in spite of these efforts.
“And then UV technology came about as an addition to manual cleaning as a way to improve disinfection,” he said. “You need to give adequate time and dose. One flash is not going to do it. But ‘X’ kilojoules of UV for ‘X’ amount of time is a lethal dose for these organisms. And the hypothesis is that killing the bugs on those surfaces leads to better patient outcomes.”
He explained that the UV light is generated by a bulb that contains a gas, like mercury vapor or an inert gas like xenon, adding, “The bulb and the intensity of the electricity across the gas produces an arc that has UV spectrum in it.”
There are three wavelength ranges within the UV light spectrum: UV-A, UV-B, and UV-C. It is within the UV-C wavelengths that the germicidal effects are achieved.
Noting that his VA medical system began to receive the initial UV disinfection systems in the 2011 time frame, Jinadatha asserted that they were one of the first ones to adapt the UV technology within the entire VA system.
“I know people thought I was crazy when we bought the first ones,” he said. “I still remember people saying, ‘You are giving an almost $50,000 piece of equipment to housekeepers who barely can keep up with the many things they are already tasked to do. How do you expect them to operate?’ I said that we couldn’t expect people to do a good job if we didn’t enable and supplement them with the latest and best technology. So we fought for it and we convinced them. And it has been a good success. People are very proud now of using them. They see that it actually makes them look better and so they actually use it more often.”
In addition to the VA, the UV technology is also demonstrating its benefits in many military medical facilities as a supplement to traditional cleaning.
According to Donnell R. Williams, chief of the Environmental Services Branch at Brooke Army Medical Center (BAMC), primary hygiene emphasis in that facility is still on FROG, an acronym for “friction rubs off germs.”
“We have to clean and disinfect with a chemical first and then we utilize the non-toxic UV disinfection to ensure a complete disinfection,” he said. “The UV disinfection through various studies has been shown to be effective in reducing superbugs and minimizing the potential of hospital-acquired infections.”
“It’s the initial friction and removal with the chemical for disinfection that we absolutely must have first,” echoed Bernadette L. Thompson, RN, BSN, CIC, chief of Infection Prevention and Control at BAMC. “We can’t do just one without the other. So they complement each other very well to allow an extreme terminal disinfection.”
Observing that there are “probably more than 20 UV disinfection systems out there today,” Williams said that BAMC received its first UV system around 2017. While declining to identify a specific manufacturer, he added that the primary system used there today is a robotic design that looks like the “R2-D2” droid from Star Wars.
Comparing the various design options available, he offered, “Some are big and bulky while some are smaller and easier to maneuver through the facility to get them where they need to go.
“And then you have different UV light,” he added. “For example, one of the systems here utilizes the pulsating xenon ultraviolet light system, and that gives you the burst of light that is supposed to kill the microorganisms a little bit better than the broad-spectrum lights.”
Asked to elaborate on the advantages and disadvantages of the different UV-generating and design technologies, Jinadatha began by pointing to a historical preponderance of mercury lamp/mercury vapor designs, with “very few” pulsedxenon lamp designs across the world.
“We mainly did research on pulsedxenon,” he said. “And the idea is that they produce varying wavelengths of UV, with UV-C mainly the germicidal UV. And the dose of output is also different [from mercury vapor designs]. So, based on those two things, the required time to disinfect may be different. For example, some of the mercury vendors require 5 minutes, some of them require 10 minutes, some of them require 20 minutes. And the pulsedxenon protocols are about 5 minutes in a couple of positions around the room, then one position in the bathroom, and you’re done. So it’s about 10 to 15 minutes of UV disinfection. It is a slightly quicker process based on their protocol, and some of that we have validated in studies to be effective in reducing the environmental contamination.”
One company applying pulsed-xenon technology is San Antonio-based Xenex, which was founded in 2009.
Founder and chief science officer Dr. Mark Stibich explained that the company’s initial disinfection studies were conducted in 2010 and published in 2011.
“We were basically looking at: Can we make a room cleaner? Can we bring down the amount of organisms in a room better than housekeeping? And the answer was yes, we are about 20 times better than traditional housekeeping at doing that. So that was really an exciting moment. And since then, I believe we’ve partnered with over 900 hospitals to bring our technology in and try to help them,” he said.
“This battle is not only against COVID,” he added. “It’s also against these antimicrobial-resistant infections and C. diff. All of these things that can be hospital-acquired infections are just horrible, because someone’s going into the hospital for one thing, and we certainly don’t want them to pick up an infection.”
The Xenex designs match the broad “R2-D2” description, with Stibich characterizing the robots as “tools for the housekeepers.”
He added, “The pathogens keep evolving. The bacteria get worse and worse and harder and harder to treat. And we need to make sure that housekeepers in the VA system have all the tools they need to do the job of making a room safe for the next patient.”
Elaborating on the underlying pulsedxenon UV technology, Stibich explained, “We are taking xenon gas, which is an inert gas, and we’re putting electricity into it to create a microsecond flash. Sometimes we do that so fast that you don’t even see it. But that flash is high intensity with high-energy UV in all these different wavelengths of what’s called germicidal UV, which is from 200 to 280 nanometers. And the reason that works really great is because it’s actually those wavelengths that are filtered by the ozone layer. Bacteria and viruses, when they evolved over 4 billion years on Earth, were never exposed to that energy. So they don’t have a lot of defenses to it, because it doesn’t naturally occur on Earth. So, they don’t have a way to protect themselves like they do from other types of light. And so we’re able to produce the whole range of wavelengths, including germicidal. And we do that at a really high intensity that’s about 4,000 times more intense than just a conventional UV light. And as a result, we’re pretty fast.”
Referring to alternative mercury-based lamp designs, he asserted, “Those obviously have mercury in them, which is something hospitals are trying to get rid of. And the VA specifically has orders to reduce the amount of mercury. It also produces a single wavelength, really concentrating on 253.7 nanometers. And that’s going to have just one type of kill, whereas we are creating different approaches, different wavelengths, different energies that we’re using, that cause different types of damage.”
Stibich said that the robot is an original Xenex design, with the company supported by an in-house engineering team that modifies and improves the robot design.
“We’ve been through about six versions of the robot to date,” he said. “The light that we’re emitting is essentially the same in each version, but we’ve learned a lot about how hospitals can be really tough on equipment. But not only do you have to deliver a great technology that has good efficacy, it has to be in a form that facilitates the use of these robots.”
Modifications have included safety features to reflect the intensity of the UV light as well as usability enhancements like an embedded tablet that provides real-time data on robot use, including who used it and where it was used.
Observing that the current design setup and movement is controlled by housekeeping staff, he said, “We’ve actually designed and tested robots with more autonomy, where they can move around a room. But surprisingly, what we found was that the number of rooms that got done dropped a lot, because hospitals are such a complex environment for trying to get a robot that moves. So it’s much better to have a person and a robot working together.”
The Xenex systems are currently in 130 VA and Department of Defense facilities, with anywhere from two to 12 robots at each site.
Looking toward the future, Stibich said, “We are continually improving the robots. And we just launched a new version of the robot, which has, again, some of those enhanced usability features. And we are continually trying to make it easier and easier for people to use and operate.”
Other recent developments include a handheld “spotlight” design that casts a 2-meter cone diameter at a distance of 2 meters.
“We’re thinking about using it in places like workstations,” he said. “From a military perspective, there are a lot of places on settings like a ship that are hard to get equipment into. By contrast, this could be carried in to provide a lot of flexibility in the format and application.”
Jinadatha agreed on the importance of simple operational design but acknowledged that challenges ranged from the reality that it can only be done in an empty room after patient discharge to the fact that light only penetrates certain areas.
“For obvious reasons, it won’t go in shadow areas or inside cabinets,” he said. “So that is an additional challenge in terms of thoroughness of cleaning. Some people debate whether that’s even needed, because nobody’s putting their hands with MRSA inside a cabinet. So you really need to disinfect it.”
Jinadatha summarized, “I firmly believe that the VA has been in the forefront in providing leadership on the adoption of newer technologies, especially things that make it a safer place for our veterans. In the trenches, I can tell you that even back in 2014, shortly after we first adopted it, I testified in front of the U.S. Congress Space and Technology Committee about this particular technology. And we reassured Congress at that time that we were doing our best. Our leadership had the courage to invest in this. We made it a safer place. We have seen the fruits of our results here in terms of preventing infections.”
He concluded, “The hope is that there will be more and more of these technologies, and we will become the leader in setting the standard for care.”
BAMC’s Williams agreed, echoing, “I believe this technology enhances the disinfection [process] and reduces the risk of pathogenic microorganism transmission. Utilizing the UV technology is quickly becoming the best practice throughout the health care cleaning community. BAMC is definitely committed to constantly looking for ways to increase the safety of our staff and patients, and the UV disinfection is definitely an added layer of protection.”