Eyeworld

127 OPHTHALMOLOGY BUSINESS October 2017 digital.ophthalmologybusiness.org enough for building disinfection," Dr. Hernandez added. EW References 1. Reed NG. The history of ultraviolet germi- cidal irradiation for air disinfection. Public Health Rep. 2010;125:15–27. 2. Chan E, et al. Treatment of infectious kerati- tis with riboflavin and ultraviolet-A irradiation. J Cataract Refract Surg. 2014;40:1919–25. 3. Price MO, et al. Photoactivated riboflavin treatment of infectious keratitis using collagen cross-linking technology. J Refract Surg. 2012;28:706–13. 4. Rutala WA, et al. Health Infection Control Practices Advisory Committee. Guideline for Disinfection and Sterilization in Healthcare Fa- cilities, 2008. U.S. Centers for Disease Control and Prevention. Last updated Feb. 15, 2017. Accessed August 2, 2017. 5. Menzies D, et al. Effect of ultraviolet germicidal lights installed in office ventilation systems on workers' health and wellbeing: double-blind multiple crossover trial. Lancet. 2003;362:1785–91. 6. Anderson DJ, et al. Enhanced terminal room disinfection and acquisition and infection caused by multidrug-resistant organisms and Clostridium difficile (the Benefits of Enhanced Terminal Room Disinfection study): a cluster- randomised, multicentre, crossover study. Lancet. 2017;389:805–814. 7. Pegues DA, et al. Impact of ultraviolet germicidal irradiation for no-touch terminal room disinfection on Clostridium difficile infection incidence among hematology-oncol- ogy patients. Infect Control Hosp Epidemiol. 2017;38:39–44. Editors' note: Mr. Mastel has financial interests with Mastel Precision. Drs. Hernandez, Jackson, and Price have no financial interests related to their comments. Contact information Hernandez: mark.hernandez@colorado.edu Jackson: mjlaserdoc@msn.com Mastel: mastelprecision@icloud.com Price: fprice@pricevisiongroup.net was significantly lower after adding UV to standard cleaning strategies," Anderson et al. wrote. However, the researchers continued, the primary outcome was not statistically lower with bleach or UV. UV-C plus quaternary ammoni- um was most effective against MRSA infections, according to the investi- gators. Using bleach instead of qua- ternary ammonium cut transmission of vancomycin-resistant enterococci by more than half, but UV light plus bleach was even more effective, cutting transmission of this bacte- rium by 64%. None of the clean- ing methods significantly reduced transmission of C. difficile, however, a separate study published in the journal Infection Control & Hospital Epidemiology found UV-C light did reduce C. difficile infections. 7 Looking toward the future Both Drs. Price and Jackson said the systems are low maintenance. Other than getting bulbs replaced, it's "a no-brainer," Dr. Jackson said. Dr. Hernandez, however, said lon- ger-lasting and safer bulbs might be a cost-effective option in the near future. He said UV producing LEDs would have a longer lifespan and avoid some of the cleanup issues that could happen if one of the current mercury-containing bulbs broke. What's more, he said LEDs are small. "You can get into nooks and crannies; you could run them in cabinetry. You can aim LEDs, and they have a defined radius of cur- vature," he said. "I'm excited to see it in applications where you don't have to use chemicals anymore and you can just line things with LED UV lights." "I wouldn't be surprised if 5 years from now, they're cheap "You have to know how to get things set up right in a clinic. These are engineering systems tailor made to a given environment," he noted. "It has to be done properly to make sure it's doing what you're saying it is." From a research standpoint, Dr. Hernandez said it is controversial still whether these systems reduce nosocomial disease transfer. "On smaller scales I think there have been some significant results, but on the broader scale the research is still tenuous about does it reduce nosocomial disease," Dr. Hernandez said. "That's where the trouble is. We don't have the statistical power to pull that out." Mr. Mastel said he thinks this is because the systems are not being used in medical applications. "If you have enough power to stop pathogen replication in the air handlers, you will indeed reduce the transmission of infectious agents. This is not controversial, just not proven according to required medi- cal standards," Mr. Mastel said. A study published in the Lancet in 2003 that studied the effect of UVGI in an office setting, specifical- ly irradiating cooling coils and drip pans of ventilation systems, found that it resulted in a 99% reduction in microbial and endotoxin concen- trations on the irradiated surfaces. The study also reported "significant- ly fewer work-related symptoms, as well as respiratory and mucosal symptoms" compared to when the irradiation system was not in use. 5 Another study published in Jan- uary 2017 in the Lancet described a cluster-randomized, crossover trial at nine U.S. hospitals where different disinfection techniques were de- ployed in rooms that previously had a patient with Clostridium difficile, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci, or multidrug-resistant Acinetobacter. 6 Among the disinfection strat- egies used—1) quaternary ammo- nium (except in cases of C. difficile where bleach was used instead), 2) quaternary ammonium and UV-C light (in C. difficile cases, bleach and UV-C light were used), 3) bleach alone, and 4) bleach and UV-C light—"the incidence of the target organisms among exposed patients which, while a powerful oxidant, poses environment and human health hazards. UVGI systems, on the whole, can be installed within air ducts to prevent room-to-room transmission of potentially infectious agents, or freestanding units can be placed in each room to disinfect the air and surfaces where the UV light can reach. Mr. Mastel said his systems do not shine the UV light directly around the room. As a result, he explained, this means the room with the system running could still be used by staff and patients without risk of UV radiation. It also protects materials in the room that could otherwise be damaged by direct UV exposure. "Rather, we use a system that only works upon the airstream com- ing through the UV reaction cham- ber and use aluminum to reflect the light so more photons are hitting the tiny particles as they come through and at an optimized dis- tance. This is the UVGI component we use with the UV-C spectral do- main," Mr. Mastel said. "The remote disinfection on the air and surfaces within the living space is performed with hydroxyls and not ozone, which is an important distinction. We use the 187-nm wavelength, specifically, but ozone is both pro- duced and consumed within the reaction chambers but is canceled with another UV frequency so they do not perfuse into the breathing atmosphere. The end product is a powerful water vapor-based disinfec- tion stream of air that works on the air that may not make it to the filter system as well as all surfaces that the air contacts, which is pretty much everywhere in the real world." In a perfect world for maximum potential of surface and air disinfec- tion, Dr. Hernandez said there would be both in-room and in-duct units. Dr. Price said his office currently has in-duct units, while Dr. Jackson said he has standalone units in his two surgical suites. Another thing Dr. Hernandez noted of UVGI systems is the im- portance of engineering them to the space. He said the size of the space, materials in it, and other environ- mental factors can impact perfor- mance. Mr. Mastel agreed. " I think anything we can do to make the environment safer for the employees and patients is helpful. " —Francis Price Jr., MD

• Blank Page
• Blank Page (1)