Medical Fabrics

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Medical Fabrics
The Latest Advancements and Current Issues

By Kris Ellis

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

Today’s 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 we’ve 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 we’ve 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 we’re 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. It’s one thing to demonstrate that on paper with a technical test, but that’s what we’re 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 it’s performing at.”

Medline Industries, Inc. currently uses DuPont’s 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 they’ve 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 it’s 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 you’re 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. “That’s 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 fabric’s barrier characteristic. “One of the things that caused us to first bring SMS to market in the mid-to-late 1970’s 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 you’re using, that’s a real risk,” he says. “I think that’s why we haven’t 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 it’s 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, you’re encouraging developing resistance in that population. It’s all part of the general precautions.”

New Fabric Applications

“We’ve just introduced a new orthopedic drape fabric. It’s very strong and has even a higher barrier than our regular Suprel line,” says Howard Corcoran, PhD, Technical Marketing Engineer, DuPont Medical Fabrics. “It’s almost impossible to tear with your hands. That’s 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 Medline’s 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 Medline’s 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. “It’s 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 it’s actually the chlorine that does the killing. It’s 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 we’ve 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 that’s why we picked that number. We truly believe we’ve 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, that’s 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, they’ll 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 they’re performing relative to the level of protection that’s 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. “We’ve adopted an AAMI color-coding system. We’ve color-coded with green for level II, purple for level III, and then dark blue for level IV, so that it’s easier for our partners to identify which barrier level they’re 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.

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