The longer you are under care, the greater the risk that instead of recovering, you will suffer a hospital infection that can be serious or fatal. This post describes the nature of the problem and some high-tech solutions; then proposes how to think about this problem when you are faced with checking yourself or a loved one in for medical care.
Caution: This is a long post. If you’re only interested in the recommendations, how to protect yourself from hospital infection, skip to the last section, “Buyer Beware.”
Hospital infection, often called hospital-acquired infection or HAI, has become an even greater concern with the emergence of deadly diseases for which there is practically no cure. Three especially bad actors are MRSA (methicillin-resistant Staphylococcus aureus), CDI (Clostridium difficile infection) and VRE (vancomycin-resistant Enterococcus).
After every surgery, the operating room is thoroughly cleaned and disinfected; the same is true for every hospital room after its patient is discharged. But these three acronym-laden microorganisims are so difficult to eradicate that they linger on even in the ultra-clean hospital environment. They await the next patient, who perhaps is already weakened by disease. And when the left-over bacteria from a previous patient hit the new arrival, he is at risk of acquiring a hospital infection, a very difficult-to-cure infection, on top of whatever reason brought him to the hospital in the first place.
My attention was drawn to hospital infection by an article forwarded by my friend Tam Mossman: “Innovator: Mark Stibich’s Hospital-Disinfecting Robot.” The writeup showed an earnest-looking man taking the top off a shiny device vaguely resembling R2-D2 in Star Wars. It seems that his machine uses ultraviolet light to kill germs in hospitals. It’s a “robot” not in the sense that it walks around or talks to you, but because it does things autonomously: you leave the room and turn it on remotely, then it raises its lamp and goes through an operating sequence to disinfect the space around it.
The article mystified me. I wondered: what’s new, anyway? And where’s the science? Everyone knows ultraviolet light is a disinfectant, and hospitals have problems with hospital infection, so one plus one is obviously two. Is this article simply some company’s efforts to promote its common stock or sell its products? No, not completely, as I learned.
Physicians who read this post will sigh in exasperation at my physicist’s ignorance of such things, but I discovered that preventing hospital infection is not a simple technical problem. Instead, it’s an interwoven battleground of science, politics, incentives, economics and, yes, genuine concern for health and lives. Although “everyone is doing everything at once,” I will display the pieces in a way that makes the most sense to me.
Historical Foundation. It’s a hundred and seventy years since Dr. Ignaz Semmelweis, the “savior of the mothers,” showed how hand washing by medical personnel could drastically reduce deaths of new mothers due to hospital infection. However, even as recently as 2006 a professor of Pediatrics at Harvard Medical School bemoaned the fact that healthcare providers are not yet following well-known necessary steps for hand washing to prevent hospital infection.
Voluntary Hygiene. Individual physicians, hospitals, groups of hospitals and caregiver organizations have mounted many programs motivated by a desire to improve medical care and reduce mortality due to hospital infection. The AMA has offered web seminars on hand hygiene; World Health Organization hand-washing instructions; highly effective multi-hospital infection control programs such as that sponsored by Duke University; and National Handwashing Awareness Week, complete with a mascot called Henry the Hand. But since two hundred years of voluntary compliance have not done the trick, it’s not surprising that more heavy-handed programs have come into favor.
Incentives. Besides the human cost of hospital infection, there’s an economic cost as well. That has helped motivate programs by insurers and government to impose financial incentives to improve hospital performance, including reductions in hospital infection. Medicare’s Hospital Value-Based Purchasing Program rewards hospitals according to the quality of care they provide. As another example, the State of Maryland’s Hospital-Acquired Conditions Program provides penalties and rewards to medical facilities according to their incidence of hospital infection.
Airborne Cleaning Agents. Every healthcare setting has developed cleaning procedures to prevent hospital infection and those incorporate surface wipe-downs with a variety of disinfectant liquids. Bleach is cheap and effective, and a standard for comparison.
It’s tedious to wipe down every surface thoroughly enough to eliminate bacterial contamination. It seems attractive to simply saturate the air with some chemical that will kill the microbes. Most chemicals that are hell on bacteria are also hell on hospital equipment, beds, sheets and walls, so companies that have taken the vapor route rely largely on hydrogen peroxide, a chemical that is very reactive for infectious agents but which decomposes into two pretty harmless materials: water plus oxygen.
One approach for sterilizing an area such as an empty hospital room is to squirt a weak solution of hydrogen peroxide and other disinfectants through a nozzle to produce a fog of submicron-sized droplets. If this fog is well dispersed through the room it can reach the “back side” of objects such as call buttons and TV remotes that the next patient is likely to touch.
However, to keep the hydrogen peroxide fog optimally reactive requires some careful control of room temperature and humidity. An alternate approach is to ionize the fog droplets with an electric discharge. It’s claimed that the ionized particles do a better and more complete job of killing microbes.
Mercury Ultraviolet Lamps. The 1976 outbreak of Legionnaire’s Disease in Philadelphia, which was associated with 34 deaths, was traced to bacteria breeding in the moist environment of the cooling tower of a hotel air conditioning system. When healthcare and engineering professionals collaborated to find a way to prevent future recurrences, they soon fastened on the “C” band of ultraviolet light, 100 to 280 nm wavelength, which has been found to be effective in destroying bacteria and spores.
A standard fluorescent lamp uses a low pressure of mercury vapor that emits ultraviolet light when excited by an electric current. 85% to 90% of the radiation is in a strong emission line of mercury, at 253.7 nanometers in the ultraviolet C-band. A household fluorescent lamp uses a phosphor coating that converts about 45% of the ultraviolet light to visible light. However, for disinfecting purposes the phosphor is omitted and the direct UV-C radiation is used.
Ultraviolet germicidal irradiation (UVGI) using mercury lamps has become a common feature of new air conditioning installations and is now required by a number of standards. For example, Section 5.8 of the General Services Administration 2005 Facilities Standards states “Ultraviolet light (C band) emitters/ lamps shall be incorporated downstream of all cooling coils in an air-handling unit, and above all drain pans to control airborne and surface microbial growth and transfer.”
When attention turned to preventing hospital infection it was natural for makers of ultraviolet lamps to offer their devices as a supplement to traditional cleaning techniques. UV lamps may be permanently installed, for example in an operating room, or brought in as a portable system. It’s important to note that the experts working in this area view all these high-tech approaches as merely an adjunct to traditional cleaning: the head of the Duke University team says, “We would never propose that the UV light be the only form of room cleaning.”
Xenon Ultraviolet Lamps. Not all ultraviolet lamps are created equal. The latest but probably not the last approach to hospital room disinfection is the Xenex system reported in Business Week (now bloomberg.com), MedCityNews and the Johns Hopkins alumni newsletter. The Xenex room-cleaning robot uses millisecond pulses of ultraviolet light produced by a lamp using xenon gas rather than mercury vapor inside its glass envelope. The xenon lamp produces a wider spectral range of ultraviolet than mercury and intense pulses rather than continuous radiation; these factors lead to a claim that xenon is “several times more effective” than mercury. A video shows the system operating in an empty hospital room. Their product invention uses the parameters of the room to control the placement and operation of the UV system to minimize the required time to clean.
Is this system in fact an advance in the battle against hospital infection? Xenex provides a list of studies at a variety of U.S. medical centers. A review of the research articles is revealing:
– A study in North Carolina showed that Xenex plus a program of hand hygiene reduced MRSA infections 56%, but didn’t try to test the UV system separately.
– Studies in Boston, Houston and Phoenix compared standard room cleaning (“terminal clean”) with various kinds of a “quick clean” supplemented with ultraviolet light. In one or another of these studies microbes were reduced 50% to 62% and hospital infection rate was reduced 33%. (Note: as of August 2015, the Cambridge and St. Joseph’s case studies quoting the 50% and 62% have been removed from the Xenex website.) However, the really big news to a hospital administrator reading these studies is that a labor-intensive cleaning process was replaced by a quick clean followed by a hands-off robotic zap. So yes, hospital infection was improved but there was an economic motivation as well.
– Economic motivation was even more evident in a Birmingham study. UV treatment was added to patient rooms, waiting rooms and cafeterias along with educational materials explaining how ultraviolet was making everything cleaner. Patient satisfaction with hospital cleanliness increased, and this would improve the hospital’s reimbursement by Medicare.
– I could find only one study, conducted in Massachusetts, that directly measured the effect of the Xenex treatment on hospital infection; when UV was added to standard cleaning, C. diff. infection rates decreased 53%.
Science Speculation: We would all like to believe that the healthcare profession is filled with dedicated and altruistic practitioners who live to make us healthier and only incidentally make a living out of it. And there is great truth in this supposition. However, it’s also true that medicine is a big and complicated business requiring the cooperation of many different specialists using constantly evolving technologies. Organizing this kind of work has become the task of hospitals and hospital systems, which conduct their altruistic aims only within the constraints of cost control and insurance reimbursement schedules.
This is a long way around of saying that the technologies described above to control hospital infection are businesses jockeying for position in the medical marketplace. Every research study is framed as a way to help save lives. But every study also has subtexts similar to these: (1) improving hospital effectiveness scores so the hospital will receive higher insurance payments; (2) reducing hospital personnel cost for cleaning procedures; (3) showing improvements in reducing hospital infection compared with “the way we used to do it.” I could not find a single study that compared all the principal cleaning procedures and equipment to find out which if any are better than their peers. Perhaps as the use of hydrogen peroxide and ultraviolet systems proliferates, a public health agency or foundation will run some systematic studies to identify one or a few “best” protocols.
Buyer Beware. Until the very best approach for controlling hospital infection is known and universally followed, going to the hospital is “buyer beware.” You don’t know whether they are using the most suitable technology, nor whether their people actually understand the equipment well enough to use it properly. The best you can hope for is to compare the hospital infection rates between different hospitals, and also see whether your preferred hospital has been improving its numbers in the last few years.
Unfortunately, only twenty-seven states require public reporting of hospital infection, although such laws have led to dramatic improvements in the states that passed them. Organizations like Consumer Reports offer survival advice to patients and (for subscribers) rate hospitals for safety according to carefully-thought-out criteria. A hospital with a strong hygiene program will be proud of its accomplishments and will help you understand the data that is available.
At our present state of understanding, the most important factors in reducing hospital infection arise from the staff themselves. Hospitals that make hygiene and infection control a major objective that is always kept in sight, that train people and measure their performance, that use supplemental cleaning tools such as ultraviolet light, that insist not only on fancy equipment but also basic hand washing and glove changing – these hospitals are doing as well as we can do today at eliminating hospital infection, and these are the safest places to entrust with your health.
You always want to know that a hospital is expert at the procedure they are going to perform. But do you also check their track record for hospital infection?
Drawing Credit: pointal, on openclipart.org