Nooks and Crannies:

June 1, 2002

Nooks and Crannies: The Breeding Grounds for Bacteria

Nooks and Crannies:
The Breeding Grounds for Bacteria

By Kelly M. Pyrek

Infection Control Professionals Urge Manufacturers toRedesign Medical Devices With IC Practices in Mind

Althoughcrude in a clinical sense, from an antiquities point of view early surgicalinstruments are considered works of art by collectors. Surgical saws, scalpels,trepan braces, trephines, forceps and lenticulars had elaborately carved handlesmade of bone, ivory, horn, ebony or mahogany, often with fancy mother-of-pearlinlays and impressions with the instrument maker's name and date of manufactureetched on to them. These instruments crafted in the late 1700s through late1800s were beautiful to look at but deadly to use, since the intricatescrollwork was a perfect breeding ground for pathogens.

Since the mid-1800s, when Louis Pasteur first proved the germ theory ofdisease and Joseph Lister first used carbolic acid as a way to help preventsurgical site infections (SSIs), medical professionals began to rethinkinstrumentation related to the ease with which bacteria could be transportedfrom patient to patient.

Even though the design of medical instruments has come a long way thanks totechnology and modern materials, there's room for improvement, say members ofthe infection control community. The design of a medical device or instrument isdictated by its inherent function, of course; however, nooks, crannies andcrevices that act as microbial reservoirs are still prevalent and problematic toaseptic technique.

"It is felt by most infection control professionals (ICPs) that it isincumbent upon the manufacturer to make a product as safe as it possiblycan," says Robert J. Sharbaugh, PhD, CIC, international director ofinfection control for Hill-Rom Inc., makers of advanced-care beds, therapysurfaces, patient-room furniture and other patient-care products."Manufacturers should try to avoid those hidden nooks, crannies and blindalleys that harbor bacteria. Things like operator controls on equipment tend tocollect goop in the crevices, so elements like flat touch-screens help eliminateplaces where microorganisms can hide."

One of the worst offenders in this game of microbial hide-and-seek areendoscopes, according to Martin Favero, PhD, director of scientific and clinicalaffairs for Advanced Sterilization Products. "The instrument most oftendiscussed is the device from hell, the GI flexible endoscope," Favero says."In 1978 the Centers for Disease Control and Prevention (CDC) convened ameeting with gastrointestinal physicians, endoscope manufacturers and CPs. Theoverwhelming consensus at that meeting is that industry should be designingendoscopes that either could be steam sterilized, which is impossible, or morerealistically, endoscopes that could be easily cleaned compared to what was onthe market. The reality is that very little has changed since then regardingendoscope design. They are still difficult to clean and let's face it, thismedical device is the one associated with the most hospital-acquiredinfections."

While gastrointestinal fiberoptic endoscopy is a valuable diagnostic andtherapeutic tool, the possibility of transmission of pathogens is too high toignore, researchers say. "Endoscopes represent a significant challenge forhigh-level disinfection or sterilization," writes David J. Weber, MD, etal., 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 disinfectingand sterilizing solutions. Instrument manufacturers therefore must actimmediately to redesign their instruments so they can be disassembled forverification of the cleaning and disinfecting/sterilizing process."

A 1995 Food and Drug Administration (FDA) study that examined endoscopes at80 U.S. healthcare facilities found 38 sites having endoscopes that were deemed"clean and ready for use" but were in fact "visibly encrustedwith debris."2 According to the American Society forGastrointestinal Endoscopy, the chances of an infectious organism beingtransmitted to a patient by one of these instruments is 1 in 1.8 million. DavidLewis, a microbiologist with the University of Georgia, when interviewed on"Good Morning America" recently said the risk is greater. "I'vecalculated, just based on the amount of blood that can leak back out of thescope after it is manually cleaned, that the infection rate may be as high asseveral patients out of 100. I think probably the actual infection rate issomewhere in between."3

Sharbaugh says medical instruments with streamlined design facilitatecleaning, a crucial preparatory step prior to subsequent disinfection orsterilization. In a paper titled "Cleaning Reusable Equipment in theICU," Sharbaugh writes, "It is a well documented fact that bacterial,viral and parasitic infections have been transmitted patient-to-patient as thedirect result of inadequate cleaning and/or disinfection of patient-care items,most notably those used in endoscopic and bronchoscopic procedures. While theoverall incidence of such occurrences is extremely low, their impact on patientoutcome can be of significant proportion."4

Organisms such as pseudomonas, klebsiella, enterobacter, serratia,salmonella, proteus and heliobacter have often been implicated in endoscope-relatedinfections.5 However, studies indicate that cleaning, either manuallyor mechanically, can achieve a 5-log reduction of contaminating microorganisms.6-7Other studies of used surgical instruments have indicated a bioburden of lessthan 100 colony-forming units (CFU) of relatively nonpathogenic microorganismsto be present after standard cleaning.8

With endoscopes' numerous lumens and channels, it is an instrument thatseemingly defies simplified design. Sharbaugh believes that in lieu of a lessintricate design, manufacturers must at the very least provide specificinstructions for cleaning and reprocessing. "Any reusable patient-caredevice should be able to be manually cleaned easily," Sharbaugh says."Manual cleaning is often the method of choice for delicate or complexdevices such as microsurgical instruments, lensed instruments and air-powereddrills. However, when possible, manual cleaning should be avoided because itincreases direct contact with contaminated surfaces."

Weber, et al, wrote, "As early as 1988, several groups suggested thatendoscopic manufacturers produce instruments that were more easily disassembledso they could be verifiably cleaned and reprocessed. Because these [endoscopes]were heat-labile, it was stressed that development of improved ways ofdisinfecting and reprocessing these instruments be developed. Either thedevelopment of more heat-stable instruments or improved methods of approachingdifficult 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 tworeasons. First, failure to adhere to current disinfection guidelines has led tocontinued outbreaks. Second, the design of endoscopes complicates adequatedisinfection including being fragile and heat sensitive, having narrow lumens,mated surfaces, sharp angles, springs and valves, occluded dead-ends, absorbentmaterials 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 beingscrutinized more closely. In 1997, when Congress was debating changes to theFederal Food, Drug and Cosmetic Act, the FDA's Department of Health and HumanServices (HHS) testified before the Subcommittee on Health and the EnvironmentCommittee on Commerce. Michael Friedman, MD, lead deputy commissioner,acknowledged, "In 1938, when the Federal Food, Drug and Cosmetic Act waspassed, medical devices, for the most part, were simple instruments such asstethoscopes and scalpels in which defects would be readily apparent. Thetechnology boom after World War II ... greatly increased the number andcomplexity of medical devices. Medical devices include more than 100,000products in more than 1,700 categories. These range from simple everydayarticles such as thermometers, tongue depressors and heating pads, to the morecomplex devices such as pacemakers, intrauterine devices, fetal stents andkidney dialysis machines. Although some of the earliest medical devices haveretained their same basic form and function, the complexity and use of medicaldevices have increased exponentially during the past 50 years. As diverse asmedical devices are, so are the range and complexity of problems that can arisefrom their use. These problems include mechanical failure, faulty design, poormanufacturing quality, adverse effects of materials, impropermaintenance/specifications, user error and compromised sterility."11

The FDA carries out its medical device responsibilities by evaluating newproducts before they are marketed for conformance to design, engineering benchtests and data from clinical trials; assures that quality systems are in placein the device-manufacturing plants; and collects and monitors adverse effectsfrom marketed products and investigates and takes action when necessary toprevent injury or death. It has been estimated that nearly half of the 1,200device recalls conducted annually are attributed to device design, and the FDAreceives 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 thetime required for decontaminating and cleaning them. "With the nursingshortage, hospital staffs are stressed and stretched, and we need to simplifycleaning tasks," says Janet M. Barber, MSN, RN, FAAFS, clinical nursingconsultant for Hill-Rom Inc. "One of the ways to do that is formanufacturers to eliminate high-maintenance elements on items such as texturedfinishes, deep embossing, open screw ports or flanges where fluids and otherdebris can collect. During basic design processes, manufacturers must considerhow much time will be required for proper cleaning, and how well the productwill withstand repeated contacts with hospital disinfecting agents."

In addition to streamlined products and devices, ICPs think manufacturersshould provide instruction as to how a piece of equipment should bedisassembled, cleaned and/or sterilized and what it can or cannot be cleanedwith.

"Most Association for the Advancement of Medical Instrumentation (AAMI)documents point out that disassembly and cleaning instructions should beincluded with the device or instrument, but AAMI does not have regulatoryauthority," Sharbaugh explains. "It would behoove manufacturers,before they design a medical device, to understand why easy cleaning of thedevice is so important."

Sharbaugh says whenever Hill-Rom engineers envision a new product they turnto him for advice. "They ask, 'What do we need to think about from aninfection control point of view?' and we point those things out. I'm not awareof any standard that requires manufacturers to consult with clinicians, butconscientious companies are doing so. If you talk to someone in manufacturingwho knows nothing about infection control -- and most of them don't becausethat'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 besequestered in bodily fluids that may be contaminated with gram-negativebacteria. You can sterilize it but you may fail to destroy microbial endotoxinsthat are heat-stable. So cleaning is an absolutely crucial step before anyterminal disinfection or sterilization process."

How responsible are medical device and instrument manufacturers when theseproducts lead to infection? Representatives from the Medical DeviceManufacturers Association (MDMA) could not be reached for comment; however, ICPsthink accountability is key.

"If they don't feel responsible for an infection related to their deviceor instrument, they should," Sharbaugh asserts. "Let's assume someonewho developed an infection associated with an endoscope decided to sue themanufacturer. Would they be successful? Who knows? I'm not an attorney, butyou'd have to prove culpability, which can be very difficult. Within the lastfew years we've seen people became purified protein derivative (PPD) skin testpositive for TB from contact with bronchoscopes that were inadequately cleaned.One would have to consider the origin of the problem, either on themanufacturer's end because the design was faulty or the user's end because itwasn't cleaned and sterilized properly. I think manufacturers need to understandwhy we place such priority on cleaning things easily and what could happen if wedon't. There's no regulation addressing the efficacy of a cleaning process, andthere's no way to measure cleanliness. You can say something met the parametersto achieve sterilization but you can't say something is sterile. AAMI is tryingto establish cleaning measurement protocols to help address this question."

"Manufacturer consultation with clinicians concerning medical devicedesign and how it impacts infection control issues doesn't happen as much as itshould," Favero agrees. "Companies who do consult with ICPs areprobably in the minority. Most devices that are meant to be sterilized areusually 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 takesdevices from manufacturers and ensures they are compatible with itssterilization products. "For example, if (the device or instrument) can beused in our Sterrad system, we want to make sure if it goes through 500 Sterradcycles, the device is not altered or corroded. We work with more than 150manufacturers; when they design a new instrument we get together and do sometesting."

Janet Barber believes manufacturers must return to the drawing board if adevice, instrument or medical product is not designed to support sound infectioncontrol practices. "When products are being initially designed, upgraded ormodified, the engineering teams should work closely with ICPs to ensure"end-user friendliness."

Barber says clinicians and manufacturers should be thinking about how eventhe 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 sourcesof contamination. Everything that can be anchored to the wall or bed, orsuspended overhead will be one less item on the floor for housekeepers to moveor work around when they clean the room. They will be able to be to a better jobin less time."

Barber points out that some product parts are tedious to disassemble andreassemble, adding to cleaning time. Personnel may even skip vital steps in thecleaning processes if they do not understand how to take an item apart and putit back together again. "Designers must remember that instruction manualsmay not be readily available to housekeeping staff. If personnel are notfamiliar with a product, they may miss hidden sites during routine cleaningprocesses. The nooks and crannies of some components may be places where usersinterface frequently with the item, (e.g. touchscreens or LCD displays coveredby panels or flip-up covers). Such areas need to be cleaned regularly becausethey are likely to have significant levels of contamination."

Ever mindful of the accumulation of bioburden, Barber says manufacturers oweit to clinicians to keep their devices and instruments free from the designcomplexities of long ago. "Manufacturers have learned the value of sleekdesigns to prevent blood, body fluids and other debris from collecting increvices and providing a media for the growth of pathogens. If healthcarefurnishing, medical devices or instruments have areas that are not beingroutinely cleaned, we must determine the reason and address it. For example, atHill-Rom, when rental products are returned to our service centers, we documentissues or problems associated with cleaning and disinfecting. They are referredto appropriate personnel for follow-up, and design engineers are made aware ofopportunities to make product modifications that would better support infectioncontrol practices."

In the mid-1990s the FDA established a Quality System Regulation to ensurethat good quality assurance practices are used for the design of medicaldevices.13 The system created a method of checks and balancesincorporated into the medical device design and development process. Thisregulation closely follows the international standard, ISO 9001 and fulfills amandate of the Safe Medical Devices Act of 1990.

Many medical device designs involve numerous technologies such aselectronics, mechanics, software, materials science and pneumatics, and avariety of clinical and manufacturing issues can influence the device orinstrument's design. In its "Design Control Guidance for Medical DeviceManufacturers," the FDA cautions that manufacturers should carefullyconsider which interests should be represented at formal device design reviews.The FDA stated, "For example, the marketing department of a smallmanufacturer shared a new design with several surgeons on their advisory board.The surgeons all thought the design was terrific. Subsequently, the manufacturerinvited two experienced operating room nurses to participate in the final designreview. During the course of the review, it became apparent that while thesurgeons may be their customers, nurses are the primary users of the device andno one up to that point had consulted with any nurses. The nurses at the designreview didn't like some of the features of the design. After further marketsurvey, the manufacturer decided to make changes to the design to accommodatethese concerns."14 In the same guidance document, the FDArecognizes that, "Hospital administrators, biomedical engineers, healthinsurance underwriters, physicians, nurses, medical technicians and patientshave distinct and sometimes competing needs with respect to a devicedesign."

Barber adds that product design is just one part of the equation when itcomes to infection control. She asserts that the entire patient-care environmentcan make or break good infection control practices. With the widespread use ofgloves, there may be a false sense of security on the part of healthcare workerssince their own hands are protected. However, gloves are efficient vehicles fortransferring contamination from one surface to another. It is imperative thathousekeeping staff members understand the principles and practices associatedwith proper glove usage as a part of their cleaning and disinfecting procedures.In today's hospital, the stature of housekeepers deserves elevation. What theydo or don't do in patient rooms is critical to the safety and well-being ofpatients and nursing personnel."

Barber adds that disposable barrier items may have given healthcare workerswhat she calls "a false sense of clean," especially if they hide anunderlying problem. "If someone puts a piece of new tissue paper on an examtable, it's considered ready for the next patient. It may not be, especially ifthe table surface has not been properly cleaned and disinfected. There are alsosome areas in hospitals that are essentially 'no-clean zones.' Housekeepers donot clean certain things because it is considered "medical" equipmentthat they should avoid; nurses may not clean them either, because it is not ahigh-priority nursing task. Consider the bracket for the wall suction unit. Theused container is taken down and discarded and a replacement is installed. Thebracket holding the receptacle that is touched multiple times by the hands ofnurses may entirely escape cleaning. Such 'no clean zones' in patient care areasmust be identified and someone needs to be designated to assume theresponsibility for cleaning and disinfecting. At Hill-Rom we make architecturalproducts so designers and engineers must always be mindful of cleaning dilemmasinherent in their headwalls and power support column."

Barber also challenges interior designers as well as manufacturers to avoidmaterials 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 hasoccurred so that the item can be cleaned. A dark floral fabric may contribute toa home-like feeling, but may pose an inherent risk of hiding soil andcontaminants in the healthcare setting. We need more plain, smooth, cleanableand light-colored surfaces that beg to be cleaned when they deserve it."