Nooks and Crannies:

June 1, 2002

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

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

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

"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

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

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."