Nooks and Crannies:
The Breeding Grounds for Bacteria
By Kelly M. Pyrek
Infection Control Professionals Urge Manufacturers to Redesign Medical Devices With IC Practices in Mind
Although crude in a clinical sense, from an antiquities point of view early surgical instruments are considered works of art by collectors. Surgical saws, scalpels, trepan braces, trephines, forceps and lenticulars had elaborately carved handles made of bone, ivory, horn, ebony or mahogany, often with fancy mother-of-pearl inlays and impressions with the instrument maker's name and date of manufacture etched on to them. These instruments crafted in the late 1700s through late 1800s were beautiful to look at but deadly to use, since the intricate scrollwork was a perfect breeding ground for pathogens.
Since the mid-1800s, when Louis Pasteur first proved the germ theory of disease and Joseph Lister first used carbolic acid as a way to help prevent surgical site infections (SSIs), medical professionals began to rethink instrumentation related to the ease with which bacteria could be transported from patient to patient.
Even though the design of medical instruments has come a long way thanks to technology and modern materials, there's room for improvement, say members of the infection control community. The design of a medical device or instrument is dictated by its inherent function, of course; however, nooks, crannies and crevices that act as microbial reservoirs are still prevalent and problematic to aseptic technique.
"It is felt by most infection control professionals (ICPs) that it is incumbent upon the manufacturer to make a product as safe as it possibly can," says Robert J. Sharbaugh, PhD, CIC, international director of infection control for Hill-Rom Inc., makers of advanced-care beds, therapy surfaces, patient-room furniture and other patient-care products. "Manufacturers should try to avoid those hidden nooks, crannies and blind alleys that harbor bacteria. Things like operator controls on equipment tend to collect goop in the crevices, so elements like flat touch-screens help eliminate places where microorganisms can hide."
One of the worst offenders in this game of microbial hide-and-seek are endoscopes, according to Martin Favero, PhD, director of scientific and clinical affairs for Advanced Sterilization Products. "The instrument most often discussed is the device from hell, the GI flexible endoscope," Favero says. "In 1978 the Centers for Disease Control and Prevention (CDC) convened a meeting with gastrointestinal physicians, endoscope manufacturers and CPs. The overwhelming consensus at that meeting is that industry should be designing endoscopes that either could be steam sterilized, which is impossible, or more realistically, endoscopes that could be easily cleaned compared to what was on the market. The reality is that very little has changed since then regarding endoscope design. They are still difficult to clean and let's face it, this medical device is the one associated with the most hospital-acquired infections."
While gastrointestinal fiberoptic endoscopy is a valuable diagnostic and therapeutic tool, the possibility of transmission of pathogens is too high to ignore, researchers say. "Endoscopes represent a significant challenge for high-level disinfection or sterilization," writes David J. Weber, MD, et al., in "The Prevention of Infection Following Gastrointestinal Endoscopy."1 "The various cracks and crevices of these instruments may contain biofilm, which is very difficult to be reached with certainty by high-level disinfecting and sterilizing solutions. Instrument manufacturers therefore must act immediately to redesign their instruments so they can be disassembled for verification of the cleaning and disinfecting/sterilizing process."
A 1995 Food and Drug Administration (FDA) study that examined endoscopes at 80 U.S. healthcare facilities found 38 sites having endoscopes that were deemed "clean and ready for use" but were in fact "visibly encrusted with debris."2 According to the American Society for Gastrointestinal Endoscopy, the chances of an infectious organism being transmitted to a patient by one of these instruments is 1 in 1.8 million. David Lewis, a microbiologist with the University of Georgia, when interviewed on "Good Morning America" recently said the risk is greater. "I've calculated, just based on the amount of blood that can leak back out of the scope after it is manually cleaned, that the infection rate may be as high as several patients out of 100. I think probably the actual infection rate is somewhere in between."3
Sharbaugh says medical instruments with streamlined design facilitate cleaning, a crucial preparatory step prior to subsequent disinfection or sterilization. In a paper titled "Cleaning Reusable Equipment in the ICU," Sharbaugh writes, "It is a well documented fact that bacterial, viral and parasitic infections have been transmitted patient-to-patient as the direct result of inadequate cleaning and/or disinfection of patient-care items, most notably those used in endoscopic and bronchoscopic procedures. While the overall incidence of such occurrences is extremely low, their impact on patient outcome can be of significant proportion."4
Organisms such as pseudomonas, klebsiella, enterobacter, serratia, salmonella, proteus and heliobacter have often been implicated in endoscope-related infections.5 However, studies indicate that cleaning, either manually or mechanically, can achieve a 5-log reduction of contaminating microorganisms.6-7 Other studies of used surgical instruments have indicated a bioburden of less than 100 colony-forming units (CFU) of relatively nonpathogenic microorganisms to be present after standard cleaning.8
With endoscopes' numerous lumens and channels, it is an instrument that seemingly defies simplified design. Sharbaugh believes that in lieu of a less intricate design, manufacturers must at the very least provide specific instructions for cleaning and reprocessing. "Any reusable patient-care device should be able to be manually cleaned easily," Sharbaugh says. "Manual cleaning is often the method of choice for delicate or complex devices such as microsurgical instruments, lensed instruments and air-powered drills. However, when possible, manual cleaning should be avoided because it increases direct contact with contaminated surfaces."
Weber, et al, wrote, "As early as 1988, several groups suggested that endoscopic manufacturers produce instruments that were more easily disassembled so they could be verifiably cleaned and reprocessed. Because these [endoscopes] were heat-labile, it was stressed that development of improved ways of disinfecting and reprocessing these instruments be developed. Either the development of more heat-stable instruments or improved methods of approaching difficult portions of the endoscopes should be developed."9
Weber continues, "Despite the adoption of disinfection guidelines, healthcare-related infections related to endoscopy continue to occur for two reasons. First, failure to adhere to current disinfection guidelines has led to continued outbreaks. Second, the design of endoscopes complicates adequate disinfection including being fragile and heat sensitive, having narrow lumens, mated surfaces, sharp angles, springs and valves, occluded dead-ends, absorbent materials and rough or pitted surfaces."10
With so many medical device-related adverse events making news these days, it's no wonder that product design, engineering and cleaning is being scrutinized more closely. In 1997, when Congress was debating changes to the Federal Food, Drug and Cosmetic Act, the FDA's Department of Health and Human Services (HHS) testified before the Subcommittee on Health and the Environment Committee on Commerce. Michael Friedman, MD, lead deputy commissioner, acknowledged, "In 1938, when the Federal Food, Drug and Cosmetic Act was passed, medical devices, for the most part, were simple instruments such as stethoscopes and scalpels in which defects would be readily apparent. The technology boom after World War II ... greatly increased the number and complexity of medical devices. Medical devices include more than 100,000 products in more than 1,700 categories. These range from simple everyday articles such as thermometers, tongue depressors and heating pads, to the more complex devices such as pacemakers, intrauterine devices, fetal stents and kidney dialysis machines. Although some of the earliest medical devices have retained their same basic form and function, the complexity and use of medical devices have increased exponentially during the past 50 years. As diverse as medical devices are, so are the range and complexity of problems that can arise from their use. These problems include mechanical failure, faulty design, poor manufacturing quality, adverse effects of materials, improper maintenance/specifications, user error and compromised sterility."11
The FDA carries out its medical device responsibilities by evaluating new products before they are marketed for conformance to design, engineering bench tests and data from clinical trials; assures that quality systems are in place in the device-manufacturing plants; and collects and monitors adverse effects from marketed products and investigates and takes action when necessary to prevent injury or death. It has been estimated that nearly half of the 1,200 device recalls conducted annually are attributed to device design, and the FDA receives more than 100,000 adverse event reports each year from manufacturers, hospitals, health professionals and consumers.12
One strong argument to be made for streamlined instruments and devices is the time required for decontaminating and cleaning them. "With the nursing shortage, hospital staffs are stressed and stretched, and we need to simplify cleaning tasks," says Janet M. Barber, MSN, RN, FAAFS, clinical nursing consultant for Hill-Rom Inc. "One of the ways to do that is for manufacturers to eliminate high-maintenance elements on items such as textured finishes, deep embossing, open screw ports or flanges where fluids and other debris can collect. During basic design processes, manufacturers must consider how much time will be required for proper cleaning, and how well the product will withstand repeated contacts with hospital disinfecting agents."
In addition to streamlined products and devices, ICPs think manufacturers should provide instruction as to how a piece of equipment should be disassembled, cleaned and/or sterilized and what it can or cannot be cleaned with.
"Most Association for the Advancement of Medical Instrumentation (AAMI) documents point out that disassembly and cleaning instructions should be included with the device or instrument, but AAMI does not have regulatory authority," Sharbaugh explains. "It would behoove manufacturers, before they design a medical device, to understand why easy cleaning of the device is so important."
Sharbaugh says whenever Hill-Rom engineers envision a new product they turn to him for advice. "They ask, 'What do we need to think about from an infection control point of view?' and we point those things out. I'm not aware of any standard that requires manufacturers to consult with clinicians, but conscientious companies are doing so. If you talk to someone in manufacturing who knows nothing about infection control -- and most of them don't because that's not their bag -- they will say, 'You're going to sterilize it anyway, aren't you?' Well, yes, but sterilization doesn't necessarily make it safe. Inadequate cleaning has the potential to allow for residual bioburden to be sequestered in bodily fluids that may be contaminated with gram-negative bacteria. You can sterilize it but you may fail to destroy microbial endotoxins that are heat-stable. So cleaning is an absolutely crucial step before any terminal disinfection or sterilization process."
How responsible are medical device and instrument manufacturers when these products lead to infection? Representatives from the Medical Device Manufacturers Association (MDMA) could not be reached for comment; however, ICPs think accountability is key.
"If they don't feel responsible for an infection related to their device or instrument, they should," Sharbaugh asserts. "Let's assume someone who developed an infection associated with an endoscope decided to sue the manufacturer. Would they be successful? Who knows? I'm not an attorney, but you'd have to prove culpability, which can be very difficult. Within the last few years we've seen people became purified protein derivative (PPD) skin test positive for TB from contact with bronchoscopes that were inadequately cleaned. One would have to consider the origin of the problem, either on the manufacturer's end because the design was faulty or the user's end because it wasn't cleaned and sterilized properly. I think manufacturers need to understand why we place such priority on cleaning things easily and what could happen if we don't. There's no regulation addressing the efficacy of a cleaning process, and there's no way to measure cleanliness. You can say something met the parameters to achieve sterilization but you can't say something is sterile. AAMI is trying to establish cleaning measurement protocols to help address this question."
"Manufacturer consultation with clinicians concerning medical device design and how it impacts infection control issues doesn't happen as much as it should," Favero agrees. "Companies who do consult with ICPs are probably in the minority. Most devices that are meant to be sterilized are usually no problem to sterilize; however, for the devices that are difficult ... that's where we don't see a lot of effort from manufacturers."
Favero says that since 1993, Advanced Sterilization Products literally takes devices from manufacturers and ensures they are compatible with its sterilization products. "For example, if (the device or instrument) can be used in our Sterrad system, we want to make sure if it goes through 500 Sterrad cycles, the device is not altered or corroded. We work with more than 150 manufacturers; when they design a new instrument we get together and do some testing."
Janet Barber believes manufacturers must return to the drawing board if a device, instrument or medical product is not designed to support sound infection control practices. "When products are being initially designed, upgraded or modified, the engineering teams should work closely with ICPs to ensure "end-user friendliness."
Barber says clinicians and manufacturers should be thinking about how even the simplest of items can be barriers to cleaning and become pathogen conduits. "We must find ways to get more items off the floors and away from sources of contamination. Everything that can be anchored to the wall or bed, or suspended overhead will be one less item on the floor for housekeepers to move or work around when they clean the room. They will be able to be to a better job in less time."
Barber points out that some product parts are tedious to disassemble and reassemble, adding to cleaning time. Personnel may even skip vital steps in the cleaning processes if they do not understand how to take an item apart and put it back together again. "Designers must remember that instruction manuals may not be readily available to housekeeping staff. If personnel are not familiar with a product, they may miss hidden sites during routine cleaning processes. The nooks and crannies of some components may be places where users interface frequently with the item, (e.g. touchscreens or LCD displays covered by panels or flip-up covers). Such areas need to be cleaned regularly because they are likely to have significant levels of contamination."
Ever mindful of the accumulation of bioburden, Barber says manufacturers owe it to clinicians to keep their devices and instruments free from the design complexities of long ago. "Manufacturers have learned the value of sleek designs to prevent blood, body fluids and other debris from collecting in crevices and providing a media for the growth of pathogens. If healthcare furnishing, medical devices or instruments have areas that are not being routinely cleaned, we must determine the reason and address it. For example, at Hill-Rom, when rental products are returned to our service centers, we document issues or problems associated with cleaning and disinfecting. They are referred to appropriate personnel for follow-up, and design engineers are made aware of opportunities to make product modifications that would better support infection control practices."
In the mid-1990s the FDA established a Quality System Regulation to ensure that good quality assurance practices are used for the design of medical devices.13 The system created a method of checks and balances incorporated into the medical device design and development process. This regulation closely follows the international standard, ISO 9001 and fulfills a mandate of the Safe Medical Devices Act of 1990.
Many medical device designs involve numerous technologies such as electronics, mechanics, software, materials science and pneumatics, and a variety of clinical and manufacturing issues can influence the device or instrument's design. In its "Design Control Guidance for Medical Device Manufacturers," the FDA cautions that manufacturers should carefully consider which interests should be represented at formal device design reviews. The FDA stated, "For example, the marketing department of a small manufacturer shared a new design with several surgeons on their advisory board. The surgeons all thought the design was terrific. Subsequently, the manufacturer invited two experienced operating room nurses to participate in the final design review. During the course of the review, it became apparent that while the surgeons may be their customers, nurses are the primary users of the device and no one up to that point had consulted with any nurses. The nurses at the design review didn't like some of the features of the design. After further market survey, the manufacturer decided to make changes to the design to accommodate these concerns."14 In the same guidance document, the FDA recognizes that, "Hospital administrators, biomedical engineers, health insurance underwriters, physicians, nurses, medical technicians and patients have distinct and sometimes competing needs with respect to a device design."
Barber adds that product design is just one part of the equation when it comes to infection control. She asserts that the entire patient-care environment can make or break good infection control practices. With the widespread use of gloves, there may be a false sense of security on the part of healthcare workers since their own hands are protected. However, gloves are efficient vehicles for transferring contamination from one surface to another. It is imperative that housekeeping staff members understand the principles and practices associated with proper glove usage as a part of their cleaning and disinfecting procedures. In today's hospital, the stature of housekeepers deserves elevation. What they do or don't do in patient rooms is critical to the safety and well-being of patients and nursing personnel."
Barber adds that disposable barrier items may have given healthcare workers what she calls "a false sense of clean," especially if they hide an underlying problem. "If someone puts a piece of new tissue paper on an exam table, it's considered ready for the next patient. It may not be, especially if the table surface has not been properly cleaned and disinfected. There are also some areas in hospitals that are essentially 'no-clean zones.' Housekeepers do not clean certain things because it is considered "medical" equipment that they should avoid; nurses may not clean them either, because it is not a high-priority nursing task. Consider the bracket for the wall suction unit. The used container is taken down and discarded and a replacement is installed. The bracket holding the receptacle that is touched multiple times by the hands of nurses may entirely escape cleaning. Such 'no clean zones' in patient care areas must be identified and someone needs to be designated to assume the responsibility for cleaning and disinfecting. At Hill-Rom we make architectural products so designers and engineers must always be mindful of cleaning dilemmas inherent in their headwalls and power support column."
Barber also challenges interior designers as well as manufacturers to avoid materials that have patterns or designs that tend to hide soiling. In hospitals, we want to either prevent soiling or at least to readily see when it has occurred so that the item can be cleaned. A dark floral fabric may contribute to a home-like feeling, but may pose an inherent risk of hiding soil and contaminants in the healthcare setting. We need more plain, smooth, cleanable and light-colored surfaces that beg to be cleaned when they deserve it."