Medical Fabrics

November 1, 2005

Medical Fabrics

The Latest Advancements and Current
Issues

By Kris Ellis


Part one in a two-part series on medical fabrics.

Todays healthcare worker (HCW) is
faced with potential exposure to a growing number of increasingly dangerous
pathogens on a daily basis. More than ever, HCWs rely on manufacturers to
provide effective and practical methods and products with which to protect
themselves. The medical fabrics that are used in the manufacture of vital
protective gear such as gowns and drapes play a crucial role in establishing a
basic level of protection, and therefore must be evaluated carefully.

The combination of protection and comfort was key for DuPont
in developing its Suprel fabric. We use multiple polymers in that product,
so weve designed a process where we can select different polymers and try to
optimize the properties of the fabric, taking advantage of the strength of the
polyester polymer that we use in that fabric, and we have the softness and the
feel of the polyethylene, says Edgar Rudisill, PhD, technical manager for
DuPont Medical Fabrics. So weve been able to use two different polymers
that each provides unique properties to that fabric.

That was really our challenge to our research department
five years ago, was to come up with a product that combined comfort and
protection in one fabric, says Lori Gettelfinger, sales and marketing manager
for DuPont Medical Fabrics. Through the use of the multiple polymers, the
polyester and the polyethylene, and the technology were using to make Suprel,
it really does give you that optimum balance of performance in terms of the
overall tactile feel, but also the breathability as measured by moisture vapor
transmission. Its one thing to demonstrate that on paper with a technical
test, but thats what were hearing day in and day out from clinicians that
are involved with trials of the fabric, is how surprisingly comfortable it is
for the high level of protection its performing at.

Medline Industries, Inc. currently uses DuPonts Suprel as
the fabric for its Aurora gown. It actually supersedes the barrier of the
polypropylene gowns, but has the comfort and feel of the spunlace gowns, so it
really kind of merges those technologies and finally gives people that one-two
punch that theyve really lacked for a long time, says Frank Czajka, senior
product manager, Proxima Gowns & Drapes, Medline Industries, Inc.

David Parks, general manager of global infection control
products at Kimberly-Clark Health Care, notes that providing excellent comfort
becomes more challenging with higher levels of protection. Clearly, the more
impervious you make a product, by default the less breathable the product is
going to become, and thus the higher the risk that it will be a hot garment and
its uncomfortable to wear, he says. One of the innovations that we brought to the market several years ago is our Microcool® breathable impervious gown that utilizes a breathable film
structure that, combined with our spunbond/meltblown/spunbond (SMS) nonwoven
fabric, really combines the best of both worlds it has the barrier
performance that exceeds the level required for an impervious product, but still
provides the breathability necessary to provide the comfort needs of a
healthcare worker.

One of the aspects that makes this combination difficult,
according to Parks, is ensuring abrasion resistance. If material does not
have good abrasion resistance, then you have fabric particles or linting, he
says. That in and of itself can be a wound contaminant in a surgical setting
that results in procedural complications or could be a vehicle for transmission
of microorganisms. If microorganisms happen to be on the surface of that garment
and it abrades and fibers are coming off, then youre creating another avenue
for those microorganisms to be transferred from one location to another.

Parks explains that Kimberly-Clark continues to leverage its
SMS-based technology as the basis for a wide range of medical fabrics, including
sterilization wrap, surgical gowns and drapes, and isolation gowns. Thats our cornerstone for providing
the highest level of protection to both healthcare workers and patients, he
says. In addition to that, we are in fact investigating what additional
performance characteristics those fabrics can provide beyond the staples that
they already provide.

These staples include combining the best in protection and
comfort, according to Parks. We know that the more comfortable the garment
is, the more likely folks are to be compliant in wearing the appropriate apparel
article for the appropriate application. So those have become the basic
requirements of apparel products providing the protection that is required,
and providing the comfort that is required. Parks notes that additional
factors must be considered as well. Other great performance characteristics
such as flammability resistance and abrasion resistance are also foundational
requirements relative to medical fabrics, he says.


Methods of Protection

According to Parks, the most critical element of protection is
the fabrics barrier characteristic. One of the things that caused us to
first bring SMS to market in the mid-to-late 1970s was that our SMS fabric
provided the ultimate fluid barrier that protected the healthcare worker from
the transmission of bloodborne pathogens through a procedure, he says.

Manufacturers continue to explore new avenues of protection. There is some work occurring at Kimberly-Clark to
understand how we take antimicrobial technology and combine it with superior
fabric performance to bring forward a higher performing product that has not
only barrier characteristics, but also an active ingredient that would kill or
control the spread of microorganism that might contribute to healthcare-acquired
infections, Parks says.

Parks points to studies that show significant contact transfer
data associated with protective apparel. One such study indicates that 65
percent of gowns are contaminated with MRSA after routine morning rounds.1

The effort to combine antimicrobial technology with
high-performing barrier fabrics is no easy task, however. Parks explains that
manufacturers must be aware of the potential to contribute to the further
development of resistant organisms. Depending on the kind of technology youre
using, thats a real risk, he says. I think thats why we havent seen more rapid
application of antimicrobials than we have.

Mike Scholla, PhD, a microbiologist at DuPont Medical Fabrics,
expresses this concern as well, and reiterates the importance of basic infection
control practices. I think its really difficult to design a specific
fabric to protect against MRSA (methicillin-resistant Staphylococcus
aureus
), he says. It boils down to the whole
concept of the overall infection control procedures and the general precautions.
Some people have talked about the possibility of embedding antimicrobials into
fabric, and there are two views on that one is that may be a good thing, and
the other is that it may be a bad thing, because when you treat a microorganism
with a sub-lethal dose of an antimicrobial, youre encouraging developing
resistance in that population. Its all part of the general precautions.


New Fabric Applications

Weve just introduced a new orthopedic drape fabric. Its
very strong and has even a higher barrier than our regular Suprel line, says Howard Corcoran, PhD, Technical Marketing Engineer,
DuPont Medical Fabrics. Its almost impossible to tear with your hands.
Thats a big point in the OR where they use different types of clamps that
could tear the drape and there could be fluids that go through the drape.

This drape fabric, used in Medlines OrthoMax Orthopedic
Drapes, is designed to give drapes high levels of strength and tear resistance.
Czajka explains that the OrthoMax line of drapes takes the Suprel technology and
tailors it to address the needs of orthopedic surgery, which is typically a
higher infection risk category. This is done by oversizing our drapes and providing
features that have been lacking for years, he says. In the OrthoMax line
we have anti-slip patient positioners on the bottom of the drape to make sure
that the drapes stay intact through rigorous procedures, and that they stay in
place, which is huge for keeping the site clean.

The other dynamic that we really took into consideration
with the development of Suprel and that OrthoMax drape line from Medline was the
fact that we wanted a product that also had excellent surface stability, says
Gettelfinger. So it was very low-linting in addition to having a high level of
fluid resistance, so that minimized any potential for particulate associated
with those very sensitive orthopedic surgeries.

HaloShield, also from Medline Industries, Inc., was developed
to address the potential transmission of microorganisms via soiled linens. The
product of a collaboration between Medline and Vanson HaloSource, HaloShield is
designed to employ the antimicrobial properties of chlorine to kill pathogens.
Ron Barth, president of Medlines Textiles Division, notes that concern about
multidrug- resistant organisms such as MRSA and vancomycin-resistant Enterococcus
faecium
(VRE) prompted research into a reusable linen
product with antimicrobial properties.

HaloShield itself is a chemical stabilizer that is grafted
into the fabric at the point of manufacture, Barth explains. Its inert
it and of itself it only has one purpose and that is to capture and anchor
residual chlorine molecules from a normal wash cycle. It anchors those chlorine
molecules, and its actually the chlorine that does the killing. Its been
well-known for quite some time that chlorine is one of the best antimicrobial
agents.

Barth says that an independent lab evaluated the effectiveness
of the HaloShield treatment by exposing treated and untreated sheets to several
pathogens, including MRSA and VRE. After ten minutes of exposure, cultures were
taken of each set of sheets. Within 10 minutes, they showed a 99.97 percent kill rate on
the treated sheets, and within 10 minutes they showed that on the untreated
sheets the bacteria had already started to proliferate and spread, Barth
says. When we saw that we knew we had something pretty powerful that worked
pretty well, and so weve been very excited about the product. Because
chlorine acts as the antimicrobial agent, Barth says there are no concerns about
potential build up of antimicrobial resistance when using HaloShield.

As far as durability goes, Barth says that after 75 wash/dry
cycles, the initial 99.97 percent rate of efficacy was very slightly decreased
to 99.7. Most of the independent data that we have says that a sheet lasts
about 75 processes, so thats why we picked that number. We truly believe weve
got a technology here that is effective throughout the lifetime of the product.

Applications of HaloShield currently include sheets and
pillowcases, with lab coats soon to come. In some panel studies with IC
nurses around the country, thats one of the areas that people said really
made sense is lab coats, because you can have touch-contamination of the fabric
from a coat, Barth says. The last product that we have in the pipeline at
this point is a cubicle curtain.

Because cubicle curtains separate semi-private rooms, or in
some cases private rooms, they were noted by that same panel group as a
potential source of cross-contamination and an area that they thought this
technology made a lot of sense in. By the end of the year we hope to launch a
cubicle curtain line that has the treatment as well.

While acknowledging that HaloShield is certainly not a
cure-all for healthcare-acquired infections (HAIs), and that linens are the not
predominant vehicle for these infections, Barth emphasizes its benefits can be
significant. There is substantial evidence that they (linens) do play a role
(in HAIs), and if HaloShield sheets can just prevent one nosocomial infection
per year, theyll pay for themselves many times over.


AAMI Standards

Standards from the Association for the Advancement of Medical
Instrumentation (AAMI) have provided an objective measure of liquid barrier
performance of protective apparel, and a classification system as well.

The AAMI guidelines are based on industry-accepted test
methods, says Jon Behm, director of research and development for convertors
at Cardinal Health. The guidelines were developed over several years by a
committee that included clinicians, leading medical organizations (e.g., AORN,
ACS, APIC), regulatory agencies (e.g., FDA), manufacturers, and industry
experts. For manufacturers, FDA recognizes the AAMI standard and requires
manufacturers to submit performance data as part of the 510K approval process
for applicable medical devices (i.e., surgical drapes and gowns, isolation
gowns).

I think it has been a very useful tool to healthcare
workers and healthcare facilities as they make decisions on defining protective
apparel for specific applications, or making decisions on where would they want
to standardize across the facility, Parks offers. In our experience over the last year or year and a half
that the AAMI guidelines have really come into the healthcare arena, it has been
a really useful tool for us as a supplier and for healthcare workers as users of
those products to classify ourselves relative to those very specific, very
well-defined performance levels, and then from a user standpoint, for them to
make an accurate assessment of the types of procedures theyre performing
relative to the level of protection thats needed.

Parks points out that education on the part of manufacturers
is critical to compliance and understanding on the part of HCWs. We employed an educational campaign to do two things: one,
to educate healthcare workers on what AAMI guidelines are all about, and then to
provide some recommendations to them on types of procedures low-fluid
procedures, medium, and high-fluid procedures and what we would recommend
they use based on these standards, he says. Then we give them some product
information relative to where our portfolio and our competitors portfolios
fall relative to those AAMI guidelines. So we tried to make it as simple and
straightforward as possible to interpret the guidelines and then apply them
to our portfolio and competitors portfolios so our customers could make
informed decisions.

Czajka also advocates continued education on the part of
manufacturers. The onus is definitely on us to be educators, he says. Weve adopted an AAMI color-coding system. Weve
color-coded with green for level II, purple for level III, and then dark blue
for level IV, so that its easier for our partners to identify which barrier
level theyre putting on and relate it back to the case to be sure that they
mesh.


Reference:

1. Boyce JM, Presented at the eighth annual meeting of SHEA;
April 5-7, 1998, Ontario, Florida; Abstract S74:52.