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ICT spoke with David J. Weber, MD, MPH, of the Departments of Medicine and Pediatrics at the University of North Carolina, Chapel Hill, to gain his perspectives on a number of important issues relating to the prevention of healthcare-associated infections (HAIs).
Q: Instrument- and device-related outbreaks are still making news, so what's most important to bear in mind relating to the proper cleaning, disinfection and sterilization of surgical instruments and medical devices?
A: One key concept for proper disinfection and sterilization is following the Spaulding classification which bases the type of disinfection and sterilization on the use of the item. Instruments that enter sterile body tissues must be sterilized; instruments and devices that touch mucous membranes and non-intact skin should at least be high-level disinfected; devices that touch intact skin should be low-level disinfected. The other key concept is that cleaning must always precede disinfection and sterilization. You can make almost any disinfection process fail if you have inadequate cleaning. The method of choice for sterilization is always steam sterilization because it has the widest margin of safety. My colleague and sterilization expert Dr. William Rutala would say too there has never been a failure of steam sterilization as long as the proper temperature is reached.
Q: Why is it important to consider the role of the environment in the transmission of pathogenic organisms?
A: In the March 2011 issue of Infection Control and Hospital Epidemiology is a paper by Dr. Shaughnessy that demonstrates if you are admitted to a patient room where the previous patient had C. difficile you have a higher risk of acquiring that pathogen. This has also been demonstrated in the past for MRSA and VRE. So we have three pathogens and multiple studies all showing that if you are put into a hospital room with a prior patient who had that disease, you could become infected. Now, the problem is not that the cleaning agents -- the quats and phenols and other disinfectants -- we have don't work, we simply don't clean hospital environmental surfaces well enough. Dr. Philip Carling has conducted numerous studies that have shown that on average, at the time of terminal cleaning, only about 50 percent of surfaces have been touched. We have two options here. One option is to improve cleaning practices, ensure better education of housekeepers, use checklists so that environmental services personnel know exactly what to do. For example, Dr. Carling uses dots of fluorescent dye, marking surfaces and then shining a black light on these surfaces to see if the dots are still there, meaning they were not removed by the cleaning process and the cleaning was inadequate. The other option is using one of the new no-touch methods such as vaporized hydrogen peroxide or ultraviolet light. Dr. Rutala and I have published a paper on the efficacy of ultraviolet lighting, showing that 15 minutes of exposure to this light will kill MRSA, VRE and vegetative bacteria, and 50 minutes of exposure time will kill C. difficile. Dr. John Boyce has looked at vaporized hydrogen peroxide, showing again that it will kill MRSA, VRE and C. difficile. His is the first study to show that by using this kind of device you could actually reduce endemic rates of C. difficile in the hospital. That's a controversial area now as to how we improve terminal cleaning. Whatever the method, we know we must perform good daily cleaning, and most importantly, we need to get healthcare workers to perform proper hand hygiene. That's how we prevent the bugs from going from patient to patient. And also the proper disinfection of shared equipment such as thermometers, blood pressure cuffs -- the things that go from room to room.
Q: Do you think the new technologies supplant or supplement evidence-based practices relating to infection prevention?
A: Just as a general rule, any human factor analysis expert could tell you it's always better to re-engineer the system than to try to educate people about it. So for example, it's better to build cars with seatbelts and airbags, as telling people to be careful while driving will meet with only so much success. In healthcare, re-engineering systems is probably easier than trying to force people to alter their behavior. But since we don't have any perfect systems to do that yet, we must reduce HAIs by education and behavior modification in part with new technology. So ultimately, I believe the new technology will be useful. The question is, how do we decide to introduce this new technology? Just because we think something works doesn't mean it will. It is the job of the manufacturer to prove it works. For example, for a new drug to enter the market, the manufacturer must prove its efficacy and safety. For a medical device, only safety must be demonstrated. So before we accept expensive new innovations we must have proof that they are safe for patients and for hospital staff, but we need to see that they actually reduce infection rates. For instance, a study in JAMA showed that a chlorhexidine sponge will reduce central-line infections; so we have introduced it at UNC and our data supports that it does work. We introduced it first in our ICUs for a year, saw evidence of success, and then we introduced it hospital-wide. So we should demand that there is evidence of efficacy within well-designed studies that show that it works to truly reduce infection rates. In these days of cost-effectiveness consciousness, any innovation must demonstrate its value to the institution. With the caveat that they must be proved to actually work, these new technologies are tremendously exciting. In conjunction with the primary investigator, Dr. Sexton at Duke, we have received a CDC grant to study the effectiveness of these new room disinfection methods in a true randomized, controlled fashion. People are always showing us new technologies and our response is, 'Provide us with the scientific papers that demonstrate benefit.' and if they have science-based evidence that a new methodology will in fact reduce our HAI rates and it is cost-effective, then we consider it. Theoretically it's a zero sum game because if you spend money on that new methodology, it takes money away from something else. And we ought to spend money on things we know will work.
Q: Do you think that zero infections is an achievable goal?
A: The public is demanding a zero rate of infections and I think that is an admirable goal, like a zero rate of plane crashes. We know that at least for HAIs at the current time, we cannot reach a zero goal -- we do not have the technical ability to do so. As soon as we start putting in IVs and placing patients on ventilators we have some risk of infection. Nevertheless we have made great strides in prevention. For instance, at my hospital, our pediatric ICU, which is in a tertiary-care academic center, will have gone one year without a ventilator-associated pneumonia (VAP) case. So the goal is zero -- we can't reach it but that should be the goal and we should always work toward reaching it. When you look at our institution's rates over the last decade, there's no magic bullet there. I can't tell you that if you do a certain intervention that your rates will go down to zero -- it's continued incremental improvement. So it's never being satisfied with where you are, and always looking at ways to improve education, process and technology to reach as low as you can, and over time our rate has steadily dropped. In our ICUs our rate of HAI-related central line-associated bloodstream infections from 1999 to 2010 dropped approximately 85 percent from roughly 9 per 1,000 line days to approximately one per 1,000 line days -- it's not one singular thing we did, but it's a number of interventions, including the use of central line kits, proper draping, the IHI bundle, chlorhexidine patches, antibiotic-impregnated catheters -- it's the multiple interventions we have introduced over the years. Every one of our ICUs has had a decreasing rate of central line infections; we are trying now to move that methodology up to the floors and we have had a dramatic continuous drop over more than a decade.
Q: What do you suggest as an effective strategy for HAI prevention?
A: The infection prevention and control department, along with other stakeholders in the hospital, need to meet regularly to look at their data and the impact of their various pathogens and infections, look at the guidelines and what is recommended, focus on the CDC/HICPAC 1A and 1B recommendations and implement those. We all have some limitations in time and budgets, so you need to look at where you have the biggest bang for your buck -- where to spend your time and your resources that will give you the greatest return on investment. Again, never be satisfied with where you are, always strive for the lowest rates but you obviously need to focus because you can't initiate 15 new projects. I think it's important to achieve a multiplier effect. For example, at our hospital we have a staff of roughly 10 people and there is only so much we can do. So we have an infection control liaison program. Many of its members are nurses but they don't have to be; they serve two functions -- we train them in best practices and then they go out and disseminate the information. If you have 30, 40 or 50 of these people, then they can do more than we can do because they are on the floor everyday. If there is a problem, they also serve as a conduit for sharing that information. In addition to this, you need to get buy-in at the unit level. We have a number of ongoing projects throughout our institution right now, all designed to improve infection prevention and control efforts and decrease infection rates. Those are being driven by people trained in how to conduct local quality improvement projects. We may provide resources and help, but it is being done at the unit level. You need the local units to initiate their own projects to help solve their major problems, which may vary from unit to unit. One unit may focus on C. difficile and another unit may have a challenge with central line infections -- regardless of the challenge the program must be focused on getting healthcare professionals in specific hospital locals to take ownership. With proper training in how to do quality improvement implementation, all that is needed is back-up from the infection control department. These outreach programs are going to be the way we have a much more dramatic impact than one infection control nurse at a hospital trying to run around and do everything.
Q: What do you think the infection prevention community focus on for the future?
A: If you went to a meeting on HIV/AIDS, you would find there would be 15 presentations of randomized controlled trials showing efficacy. You go to SHEA and I would be surprised if there are 10 randomized trials and there may be only one or two, and that's because even though HAIs are the sixth leading cause of death in the U.S., there is not much funding in general to do the research we need to do. Unlike drugs that might make millions or billions, most innovations or technologies don't generate near as much profit so companies are not willing to conduct multi-million dollar studies. There has not been much in the way of NIH support for research for HAIs because they look at that as practical rather than basic research. The CDC, which is funding us in other studies, has nowhere near the research resources of NIH. It's a difficult financial time to make those pleas, but we need sufficient research funds to design appropriate multicenter trials through SHEA or through other investigators to answer critical questions in infection prevention and control -- to demonstrate if what we think works does actually work or doesnt work. Obviously SHEA is working through its research group to do that, the CDC, through its Epicenter has done that, but we really need many more research efforts. I don't think it's a lack of expertise, because who knows better how to design studies than hospital epidemiologists? It's really a lack of resources to conduct the studies. I don't criticize the investigators at all and I'm not entirely critical of the companies because many of them are small and don't have the resources. I am, however, critical of our political system for not providing the resources for what is a major public health hazard that would allow us to base what we do on science. All of us need to read the studies and be critical reviewers of the literature and insist on proper scientific studies to change practice. At the same time, once the scientific evidence shows it works, we need to be more prepared to immediately integrate it into our armamentarium against HAIS and to push it through our systems to get the funds and training to introduce those new technologies and systems. There's no question, however, that we are doing much better than we have done in the past and we've seen a significant and dramatic reduction in HAIs over time.