Medical Fabrics

November 1, 2005

Medical Fabrics

The Latest Advancements and CurrentIssues

By Kris Ellis

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

Todays healthcare worker (HCW) isfaced with potential exposure to a growing number of increasingly dangerouspathogens on a daily basis. More than ever, HCWs rely on manufacturers toprovide effective and practical methods and products with which to protectthemselves. The medical fabrics that are used in the manufacture of vitalprotective gear such as gowns and drapes play a crucial role in establishing abasic level of protection, and therefore must be evaluated carefully.

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

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

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

David Parks, general manager of global infection controlproducts at Kimberly-Clark Health Care, notes that providing excellent comfortbecomes more challenging with higher levels of protection. Clearly, the moreimpervious you make a product, by default the less breathable the product isgoing to become, and thus the higher the risk that it will be a hot garment andits 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 filmstructure that, combined with our spunbond/meltblown/spunbond (SMS) nonwovenfabric, really combines the best of both worlds it has the barrierperformance that exceeds the level required for an impervious product, but stillprovides the breathability necessary to provide the comfort needs of ahealthcare worker.

One of the aspects that makes this combination difficult,according to Parks, is ensuring abrasion resistance. If material does nothave good abrasion resistance, then you have fabric particles or linting, hesays. That in and of itself can be a wound contaminant in a surgical settingthat results in procedural complications or could be a vehicle for transmissionof microorganisms. If microorganisms happen to be on the surface of that garmentand it abrades and fibers are coming off, then youre creating another avenuefor those microorganisms to be transferred from one location to another.

Parks explains that Kimberly-Clark continues to leverage itsSMS-based technology as the basis for a wide range of medical fabrics, includingsterilization wrap, surgical gowns and drapes, and isolation gowns. Thats our cornerstone for providingthe highest level of protection to both healthcare workers and patients, hesays. In addition to that, we are in fact investigating what additionalperformance characteristics those fabrics can provide beyond the staples thatthey already provide.

These staples include combining the best in protection andcomfort, according to Parks. We know that the more comfortable the garmentis, the more likely folks are to be compliant in wearing the appropriate apparelarticle for the appropriate application. So those have become the basicrequirements of apparel products providing the protection that is required,and providing the comfort that is required. Parks notes that additionalfactors must be considered as well. Other great performance characteristicssuch as flammability resistance and abrasion resistance are also foundationalrequirements relative to medical fabrics, he says.

Methods of Protection

According to Parks, the most critical element of protection isthe fabrics barrier characteristic. One of the things that caused us tofirst bring SMS to market in the mid-to-late 1970s was that our SMS fabricprovided the ultimate fluid barrier that protected the healthcare worker fromthe 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 tounderstand how we take antimicrobial technology and combine it with superiorfabric performance to bring forward a higher performing product that has notonly barrier characteristics, but also an active ingredient that would kill orcontrol the spread of microorganism that might contribute to healthcare-acquiredinfections, Parks says.

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

The effort to combine antimicrobial technology withhigh-performing barrier fabrics is no easy task, however. Parks explains thatmanufacturers must be aware of the potential to contribute to the furtherdevelopment of resistant organisms. Depending on the kind of technology youreusing, thats a real risk, he says. I think thats why we havent seen more rapidapplication 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 infectioncontrol practices. I think its really difficult to design a specificfabric to protect against MRSA (methicillin-resistant Staphylococcusaureus), he says. It boils down to the wholeconcept of the overall infection control procedures and the general precautions.Some people have talked about the possibility of embedding antimicrobials intofabric, and there are two views on that one is that may be a good thing, andthe other is that it may be a bad thing, because when you treat a microorganismwith a sub-lethal dose of an antimicrobial, youre encouraging developingresistance in that population. Its all part of the general precautions.

New Fabric Applications

Weve just introduced a new orthopedic drape fabric. Itsvery 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 thatcould tear the drape and there could be fluids that go through the drape.

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

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

HaloShield, also from Medline Industries, Inc., was developedto address the potential transmission of microorganisms via soiled linens. Theproduct of a collaboration between Medline and Vanson HaloSource, HaloShield isdesigned to employ the antimicrobial properties of chlorine to kill pathogens.Ron Barth, president of Medlines Textiles Division, notes that concern aboutmultidrug- resistant organisms such as MRSA and vancomycin-resistant Enterococcusfaecium (VRE) prompted research into a reusable linenproduct with antimicrobial properties.

HaloShield itself is a chemical stabilizer that is graftedinto the fabric at the point of manufacture, Barth explains. Its inertit and of itself it only has one purpose and that is to capture and anchorresidual chlorine molecules from a normal wash cycle. It anchors those chlorinemolecules, and its actually the chlorine that does the killing. Its beenwell-known for quite some time that chlorine is one of the best antimicrobialagents.

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

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

Applications of HaloShield currently include sheets andpillowcases, with lab coats soon to come. In some panel studies with ICnurses around the country, thats one of the areas that people said reallymade sense is lab coats, because you can have touch-contamination of the fabricfrom a coat, Barth says. The last product that we have in the pipeline atthis point is a cubicle curtain.

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

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

AAMI Standards

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

The AAMI guidelines are based on industry-accepted testmethods, says Jon Behm, director of research and development for convertorsat Cardinal Health. The guidelines were developed over several years by acommittee that included clinicians, leading medical organizations (e.g., AORN,ACS, APIC), regulatory agencies (e.g., FDA), manufacturers, and industryexperts. For manufacturers, FDA recognizes the AAMI standard and requiresmanufacturers to submit performance data as part of the 510K approval processfor applicable medical devices (i.e., surgical drapes and gowns, isolationgowns).

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

Parks points out that education on the part of manufacturersis 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 toprovide some recommendations to them on types of procedures low-fluidprocedures, medium, and high-fluid procedures and what we would recommendthey use based on these standards, he says. Then we give them some productinformation relative to where our portfolio and our competitors portfoliosfall relative to those AAMI guidelines. So we tried to make it as simple andstraightforward as possible to interpret the guidelines and then apply themto our portfolio and competitors portfolios so our customers could makeinformed decisions.

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

Reference:

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