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Bug Zapper
Room-disinfection robots shoot beams of ultraviolet light to reduce the bacterial count on surfaces you might have missed.
Lou Ann Bruno-Murtha
Publish Date: March 24, 2014   |  Tags:   Infection Prevention
disinfection robots

We were behind in the battle against Clostridium difficile infection at 2 of our hospitals last year, both beset by an alarming spike in the number of C. diff cases. Despite attention to cleaning with our hospital-approved cleaner and bleach, good compliance with cleaning high-touch surfaces and hand hygiene, we needed to do more to ensure eradication of the pesky spores. We decided to enhance terminal room disinfection against the invisible enemy with ultraviolet disinfection. Our environmental services staff wheels the R2-D2-shaped devices into patient rooms after the routine terminal clean to kill bacteria and spores that may persist despite the thorough manual cleaning. I don't know for sure how much credit these backyard bug zappers on steroids deserve for curbing our C. diff flare-up, but by all early indications, they appear to have resulted in a decrease in rates at both of our hospitals since deployment.

Look at the numbers. At our Cambridge campus, we had 8 C. diff cases in the first quarter of last year. Given Cambridge's size, we're expected to have no more than 3.5 cases in any quarter. In the quarters after we deployed the UV robot, we've had 1 case, then 4 and then 2. Yes, we're doing remarkably better.

The spike-and-drop story was even more dramatic at Whidden Hospital in Everett, Mass. In the fourth quarter of 2013, we had 9 C. diff cases there; we're expected to have no more than 3 per quarter. We've had 3 cases through nearly a full quarter this year since we deployed the UV robot in November.

When it comes to C. diff, there can be many culprits. Perhaps improved hand hygiene has played a part in the reduction. Use of any antibiotic can potentially lead to C. diff disease. Increasing age, comorbidities, proton-pump inhibitors and GI surgery are other risk factors. One thing I can say is that our patients are benefiting from the UV disinfection systems. We routinely use UV disinfection after the terminal clean in rooms where patients are on contact precautions. We prioritize C. diff rooms, but also focus on MRSA and other multidrug-resistant organisms (MDRO) that may persist on surfaces and pose an increased risk to the next patient. We're excited that we've used this technology to enhance terminal room cleaning in our ORs, too.

germ-killing robot MISSED A SPOT? It may look like a futuristic gadget from a science fiction movie, but this germ-killing robot can kill harmful bacteria on surfaces.

What studies have shown
A study we presented at last year's Association for Professionals in Infection Control and Epidemiology annual meeting showed that the pulsed UV room disinfection system reduced surface contamination in the OR by 81% and air contamination by 46%.

My colleagues and I evaluated the effects of pulsed xenon ultraviolet disinfection by comparing bacterial contamination on surfaces and in the air of ORs after standard cleaning and a quick clean — defined as cleaning the table and visibly soiled areas — followed by UV disinfection.

Enhanced disinfection has been shown to reduce the contamination levels in ORs at terminal clean. We wanted to see if these results could be replicated for between-case cleaning. We demonstrated that while between-case contamination continued to rise from case to case with standard cleaning, it was reduced to almost zero with the pulsed xenon UV disinfection device. This suggests that enhanced disinfection in a busy OR may improve patient safety, particularly if your surveillance demonstrates that environmental contamination may be contributing to an increase in surgical site infections. Although we were initially excited about our findings in our OR, further investigation showed that the bacterial isolates were exclusively skin flora and not pathogens associated with our SSIs. Further investigation will be needed to determine whether UV disinfection can reduce ?surgical ?site infections. Nonetheless, we've incorporated routine UV disinfection after terminal cleaning in our OR.

Research shows that hospital cleaning teams using standard cleaning practices frequently don't disinfect all of a room's surfaces, with more than half of the surfaces remaining neglected. For our study, we sampled 12 surfaces in 2 ORs before and after between-case cleaning, including the anesthesia keyboard, anesthesia cart, anesthesia controls, intravenous infusion pole, overhead lamp, bed control, Bair hugger control, floor, nurse's mouse, cautery power control, inside door surface and Mayo stand. Four 5-minute UV treatment cycles were performed at standardized locations in the OR. As mentioned, the study showed that the UV system reduced surface contamination with skin flora by 81% and air contamination by 46%. Future studies should include patients colonized and/or infected with MDROs, as well as patients with contaminated wound classes, since environmental contamination with pathogenic bacteria would be expected in these cases.

ultraviolet light device AFTER THE TERMINAL CLEAN An ultraviolet light device being wheeled into the OR.

Finishing touch
UV systems are engineered to disinfect line-of-sight surfaces from one or more positions within a room, overcoming human error such as missed and difficult-to-reach surfaces, and improper chemical application. Our current policy is to change privacy curtains after we discharge a patient who'd been on contact precautions. This is a time-consuming process in which an environmental service worker has to climb a ladder, unhook the old curtain and reattach a new one. We're exploring whether UV treatment can disinfect curtains so that we could maintain those that aren't visibly soiled.

Should you deploy UV systems to prevent dangerous health care-associated infections or to halt outbreaks? When it comes to infection prevention, it's obviously better to be proactive than reactive, but it's probably most practical for OR managers to add automated no-touch disinfection technology to your comprehensive manual cleaning routines already in place. So think of UV not as a replacement for mops and pre-moistened wipes, but as a powerful finishing touch that can kill germs on surfaces that, for whatever reason, your clinical cleaning team or environmental services staff passed over.

You'll need to factor time into the equation. Depending on the size of the OR and the UV system that you use, UV disinfection can take as little as 15 minutes to as long as 40 minutes, certainly not in keeping with same-day surgery's brisk turnover times, scheduling pace and shorter case times. Here's our UV schedule:

  • Our surgeons can request UV-disinfection of the room before or after a certain case (a known C. diff carrier, for example) to be certain that we eliminate spores completely or prior to prosthetic material being placed in a high-risk patient.
  • We UV-disinfect our prosthetic joints OR every night.
  • We UV-disinfect other rooms at day's end after the terminal clean as often as possible.

Our study showed that between-case contamination in the OR continued to rise from case to case with standard cleaning, increasing after the third case, perhaps because of a cumulative effect. Contamination was reduced to almost zero when the UV device was used between cases. While between-case UV disinfection may not be practical for most ORs, consider adopting this technology after a day's worth of cases to rest assured that you are providing an optimal environment for patients in the morning.

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