Blog/Focus: Infection Control

How typical ceiling light fixtures can help reduce HAIs

By Clifford J. Yahnke, PhD / Special to Healthcare Facilities Today
October 26, 2017
>Spring Valley Hospital, Las Vegas, hybrid cardiac operating suite installation showing indigo-only mode

According to the Centers for Disease Control and Prevention (CDC), approximately 1 in every 25 U.S. hospital patients contracts an infection in a health care setting.  This amounts to approximately 1.7 million infections each year, with approximately 99,000 of those infections ending in the patient’s death. Battling a Healthcare- Acquired Infection (HAI) can often add tens of thousands of dollars to the cost of treating a single patient and can result in significant financial penalties and lower Medicare reimbursements for those health care providers who score poorly relative to their peers in this area.  For example, the excess cost of a single Surgical Site Infection (SSI) is, on average, $20,785, with much higher costs for complex procedures such as orthopedic joint replacements.1

Healthcare providers are continually looking at a variety of interventions they can bundle to collectively reduce their SSI rates2,3. These interventions typically include a range of activities focused directly on the patient, such as screening for MRSA/MSSA, CHG skin prep, antibacterial sutures, and incisional adhesives. What is often minimized or overlooked in this approach is the influence of the environment on wound contamination, and the increased risk of infection it creates.

While these efforts are certainly logical, they ultimately reach a point of diminishing return, as they require people to implement; making it costly to perform as well as introducing the potential for human error. This challenge is best exemplified by a simple comparison with hand washing. Every provider knows they need to perform and improve hand washing, yet the average compliance rate for hand washing across the US is less than 50% at many organizations4,5. This highlights the impracticality of expecting workers to wash their hands after each potential exposure. To do so would slow the delivery of healthcare to a crawl. With decreased reimbursements forcefully improving environmental hygiene is simply not practical in today’s healthcare environment.

With this in mind, it’s imperative healthcare organizations focus on facility design, operations and management to help prevent the spread of HAIs.

Improving environmental hygiene- The case for whole room disinfection

Healthcare providers are increasingly looking for solutions that provide a safety net by disinfecting surfaces that may have been insufficiently disinfected. Typically referred to as “whole room disinfection”, such solutions exist to compliment or bolster their current cleaning efforts. These technologies are commonly segmented by the time over which the disinfection occurs. Most products and technologies are effective for the short period of time over which they are applied as an extension of their regular cleaning protocols. Such efforts are commonly referred to as “episodic”. By comparison, those products and technologies that operate over an extended period of time (e.g. HEPA air filters) are referred to as “continuous”. Either form of disinfection is optimized for a specific application and, therefore, has advantages and disadvantages. Of course, any effort to remove bacteria from the environment is desirable, but given the fact that every healthcare provider has a limited amount of resources to deploy, their choice must ultimately balance product effectiveness vs. total cost of ownership. So what are some options?

LED technology

LED technology affords the healthcare facilities staff the opportunity to employ highly customized, narrow-spectrum light that provides a range of non-visual benefits for applications such as healthcare. One of the applications, which has garnered less public attention to date but can have significant and far reaching benefits, is continuous visible light disinfection.  

Sunlight has been used throughout the course of history to kill bacteria in various settings.5,6  This phenomenon was thought to be largely due to the presence of germicidal ultraviolet (UV) radiation within the solar spectrum.  It wasn’t until approximately 15 years ago that researchers at the University of Strathclyde discovered a second disinfecting element within sunlight.  Further research by this same group later confirmed that a narrow spectrum of visible, indigo-colored light (405+/-5nm) had a germicidal effect on various medically important bacteria without the need for additional sensitizers.7,8,9  The University subsequently created prototype devices wherein the disinfecting spectrum was integrated with overhead lighting to create a whole-room, environmental disinfection device.4 The University was later awarded two different patents for this work and, today, a single manufacturer has commercial authority to create products using this underlying technology.10

Visible light disinfection – The merger of science & lighting

Visible light is an ideal medium for continuous environmental disinfection because virtually every indoor space uses overhead lighting. The visible light scatters from hard and soft surfaces, allowing it to fill the room and provide a ubiquitous disinfection effect. At the same time, integration of this disinfection technology into the room’s overhead lighting requires careful consideration of the underlying visual needs of the room’s users and their occupancy patterns.  For example, an operating room has a large amount of ambient white light (200-300 fc near its center) and is in use for roughly 12 hours per day. This defines the amount of disinfecting light that can be introduced into the room without compromising visual acuity.  Since the room is only in use for 12 hours per day, an alternative mode of operation—using Indigo light only—provides substantially higher levels of disinfection, leaving the room in a cleaner state for the start of the next day.  Together, these two modes of operation ensure 24/7 disinfection of the space.

These two modes of operation can be automatically controlled, as would normal lights, using occupancy sensors within the room.  This automation eliminates the need for additional labor and training, while ensuring compliance.  Also, because it uses LED’s, the technology lasts for years without maintenance.  The end result is that these products that can offer an ROI of less than 1 year by preventing just a single infection.

Ultimately, these tradeoffs are underpinned by an understanding of the clinical, rather than laboratory, performance of the product; with the key differences being the varying light levels within the room throughout the day, the environmental conditions affecting the bacteria, and the continuous reintroduction of bacteria into the environment by people within the space.


With increasing public awareness of the growing superbug threat, healthcare organizations will look to use every tool at their disposal to reduce HAIs, including the building itself.  Visible light disinfection is an emerging lighting application providing non-visual benefits that align with this goal.

Clifford J. Yahnke, PhD, is the Director of Clinical Affairs for Indigo-Clean.


1 Zimlichman E., et al. “Health Care-Associated Infections: A Meta-analysis of Costs and Financial Impact on the US Health Care System”, JAMA Intern Med 2013; 173:2039-46

2 Keenan J.E. MD, et. al. “The Preventive Surgical Site Infection Bundle in Colorectal Surgery An Effective Approach to Surgical Site Infection Reduction and Health Care Cost Savings”, JAMA Surg. 2014; 149:1045-1052

3 Spencer M., et. al. “A 7 S Bundle Approach To Preventing Surgical Site Infections”, APIC 2014


5 McGuckin M., et. al. “Hand Hygiene Compliance Rates in the United States—A One-Year Multicenter Collaboration Using Product/Volume Usage Measurement and Feedback”, Am J Med Quality 2009, 24: 205-13

6 Pyrek K., “Surveys Reveal Hospital Leaders, IPs Share Concerns About Barriers to Environmental Hygiene”, Infection Control Today Special Report, June 2015

7 Anderson D., 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”, The Lancet 2017; Jan 16

8 Fornwalt L., et al. “Influence of a total joint infection control bundle on surgical site infection rates”, Am J Infec Control 2016; 44: 239-241

9 Catalanotti A., et. al. “Influence of pulsed-xenon ultraviolet light-based environmental disinfection on surgical site infections”, Am J Infect Control 2016; 44:e99-e101

10 Alfa M., et. al. “Use of a daily disinfectant cleaner instead of a daily cleaner reduced hospital- acquired infection rates”, Am J Infec Control 2015; 43: 141-146

11 Murrell L., et al. “Improving Environmental Hygiene in the OR Using Continuous Environmental Disinfection”, in press

12 Weber D., et al. “Effectiveness of ultraviolet devices and hydrogen peroxide systems for terminal room decontamination: focus on clinical trials”, Am J Infec Control 2016; 44: e77-84

13 Spencer M., et al. “A model for choosing an automated ultraviolet-C disinfection system and building a case for the C-suite: Two Case Reports”, Am J Infec Control 2017; 45: 288-92


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