The Potential of Continuous Active Disinfection (CAD): The Clean Does Not Fade Away
There have been some seismic shifts in how we provide healthcare over the past few decades. In the mid-1980s, we went from mouth pipetting in the lab and infrequently wearing gloves for hands-on patient care to universal precautions. Prior to 2000, hand hygiene was predominated by the use of soap and water before the mass adoption of alcohol-based hand sanitizers.1 Public reporting of healthcare-associated infections (HAIs) upended the apple cart of infection prevention leading to programs such as the Inpatient Prospective Payment System and a renewed focus on surveillance and prevention efforts. These shifts can be external due to the world around us (universal precautions) or as a result of new discoveries or innovations (alcohol-based hand rubs), but they are usually disruptive to mindsets, workflows, and measures of success.
Today, we seem to be on the precipice of another potential shift. Until recently, disinfection of environmental surfaces could be best characterized as an interim state. For example, a surface becomes contaminated, a disinfectant is then applied for the prescribed contact/wet/kill time – effectively reducing the number of contaminating organisms by several log reductions, and over time, that same surface in the healthcare setting becomes re-contaminated – warranting another application of disinfectant at regular intervals.2
These regular intervals make a difference. Arguably the most significant difference in contaminating healthcare worker hands are the vectors between the infected/colonized patient and the susceptible patient.3
Enter continuous active disinfection. Previously, we may have had limited materials that were inherently bacteriostatic – but we are now entering a new era with spray-on chemicals that demonstrate ongoing bactericidal activity for a prescribed period of time. If you are an infection preventionist or microbiologist, this may strike you as odd, to put it mildly.
Instead of a disinfectant that kills immediately and then reapplied at an indeterminate frequency, this disinfectant can be applied once and continue working against common pathogens long after you leave. But like other paradigm shifts its optimal utilization is best achieved when the context of human factors engineering is part of the implementation process.
What is Continuous Active Disinfection (CAD)?
Continuous Active Disinfection is the application of a surface chemical that has intermediate level disinfection on contact and then continuously disinfects potential pathogens that land on the surface thereafter. Think of it as a shield that can withstand organisms for some prescribed time. Inherently it leaves behind a residue or film – letting you know it is there.
The EPA has approved these products based on scientific data submitted. They are based on the premise that you can spray or wipe once and expect residual activity thereafter for a prescribed period of time or a defined number of touches.4,5 Essentially, you disinfect a surface with a CAD, walk away, and it continues killing specific organisms for the prescribed time or touches to the surface – like a temporary shield.
How Do I Use CAD?
Here is where the rubber meets the road if you will. It may seem tempting to use this CAD in immediate care areas–patient rooms, bedside tables, and bedrails–where it has been shown to be effective.6 That’s not wrong. But, if we think about this new technology, it makes sense to use it in areas or processes where disinfection is inherently impaired.
Common areas, or more commonly, waiting areas in ambulatory care, are often underserved. Think of your waiting areas, your ambulatory care lounges, the places that, if we’re being honest, are often disinfected no more than once a day. A Family Medicine ambulatory care area or, a Pediatric Clinic – how often are the chairs and tables disinfected? Arguably, once a day – at night.
Now imagine these areas are still disinfected once per day – as human factors would prescribe, but you use a chemical that continues disinfecting throughout the following day. Patient 1 sits down, sets their coffee on the nearby table, gets up, goes to their appointment and Patient 2 sits down – but in the interim, the organisms from Patient 1 have been killed. That is the potential of a CAD.
In a recent study, Donskey and colleagues assessed the utility of a CAD on non-dedicated patient care equipment in acute and subacute facilities.7 They found that the CAD outperformed traditional quaternary ammonium-based healthcare disinfectants in maintaining a significant log-reduction of organisms over baseline. While few infection preventionists would like to see CAD supplanting routine disinfection following use, many would also recognize that compliance with achieving this goal is often underwhelming.
What are the Problems with Using CAD?
Analogous to supplemental disinfection with UV, there stands the potential of not cleaning when we disinfect, relying too heavily on new technology and assumptions around utilization. The good news is that recent formulations are analogous to current methods – wipes and sprays. Yet, educating healthcare workers on this new paradigm requires some nuance. We have a new chemical – it keeps working after you use it, and that is ok.
However, continuous active disinfection does not supplant the need for ongoing disinfection of non-dedicated patient care equipment or surfaces. CAD is an adjunct to traditional modalities-not a replacement. Furthermore, the use of CAD products may require organizations to consider potential unintended consequences of their use. If a CAD leaves behind a visible shield/film of protection it may be perceived by persons -both patients and staff alike-as visibly soiled. Customers, healthcare-related or otherwise, are all about expectations.
A simple, multi-lingual sign articulating why there is a film on surfaces and why will help alleviate concerns. That film I see in the waiting room of my doctor’s office– that is not dirty – it’s protected. That is a paradigm shift analogous to why are you wearing gloves when you’re taking a blood sample or why are you using alcohol-based hand rub instead of washing your hands with soap and water? Things change, and we change with them.
6. American Journal of Infection Control 2019 Mar 9. pii: S0196-6553(19)30101-4. doi: 10.1016/j.ajic.2019.02.013