What You Always Wanted to Know About Wrapping Materials

November 1, 2000

What You Always Wanted to Know About Wrapping Materials

What You Always Wanted to Know About Wrapping Materials

By Julie Stoller, CRCST

TheFood and Drug Administration (FDA) classifies sterilization wraps as Class IImedical devices requiring the following performance standards: "The primepurpose and function of a packaging material (pack, sterilization wrapper, bag,or accessories) is to enclose a medical device that is to be sterilized by ahealthcare provider. It is intended to allow sterilization of the encloseddevice and also to maintain sterility of the device until it is used."

Wrapping materials are classified in two categories: woven reusable materialsand nonwoven materials intended for single use. This article provides a closelook at the various types of wrapping materials and the importance of wrapcompatibility with the sterilization process chosen. In addition, the role theCentral Service technician plays in achieving the desired outcome of properlysterilized products will be discussed.

There are three important parameters that must be met for any type of sterilepackaging used. The first is to provide an effective barrier between the packagecontents and microbiological contamination, the second is to allow forpenetration of the chosen sterilant, and the third parameter is that the packagemust be constructed in a manner that allows the package to be openedaseptically.

Multiple-use or Reusable Textiles

Allwrappers made of woven textiles are reprocessable and must be laundered betweenuse. Woven textile fabrics to be used as sterilization wrappers are made ofnatural fibers of cotton, linen, and/or blends of cotton and syntheticmaterials, such as polyester (nylon) and chemically treated fibers (Quarpel), invarious thread counts (number of threads per square inch) and thread weights.The higher the thread count, the denser the barrier.

Early Woven Textiles

Cotton muslin was one of the first fabrics introduced to the healthcareindustry as a multi-use wrapper. It has a thread count of 140 threads per squareinch and is 100% loosely woven cotton. To enhance the barrier qualities, adouble wrap was recommended. It was later discovered that the effectiveness wascompromised during the sterilization process once it became wet, regardless ofthe number of layers used.

Pima cotton or T-280 is a more densely woven cotton fabric with improvedbarrier qualities and capabilities for withstanding repeated use and laundering.This fabric was originally developed by the Shirley Institute in Manchester,England, during WWII and was used in flight suits. Pima Cotton was replaced by apolyester/cotton blend.

The most common reusable textiles used in healthcare facilities today areblends or barrier cloth. This type of woven wrapper is made of a combination oftwo or more types of fibers in one yarn for the purpose of maximizing thebenefits of their individual performance characteristics. In many healthcarefacilities, the most popular blend is a 50% polyester/50% combed cotton percale.The benefits of this material are that it is wrinkle-free, resistant to abrasionand linting, and very durable. One negative aspect of this fabric, however, isits low water-resistant capability. As mentioned earlier, a chemical treatment (Quarpel)can be applied to increase moisture resistance. Information for properapplication of this water-repellant chemical should be obtained from themanufacturer. The healthcare facilities that choose woven textiles for theirsterile wraps must have a policy in place to inspect the fabric for any defects.

Non-woven, Single-Use (Disposables)

Non-woven,single-use or flat wraps are made by methods other than weaving, allowing washedpaper pulp, cellulose fibers, and synthetic fibers of nylon and/or other plasticpolymers to be pressure-bonded together to form sheets of fabric.

Washed paper pulp, or wet-laid fabrics, consists of wood pulp and polyester.A blend of these fibers is suspended in water to form slurry--a thin mixture ofwater and any of several fine insoluble materials--to ensure uniformity. Thewater is then drained, resulting in a durable material suitable for many uses.

Spunlace fabrics, such as wet-laid fabrics, are composed of wood pulp andpolyester. The difference between the two is in the manufacturing process. Thefibers of spunlace fabrics are subjected to high-pressure water jets that mix orentangle the fibers, producing a soft, drapable material.

Polypropylene base is a material made of polypropylene pellets that aremelted and then extruded in one continuous filament, then bonded together toform a durable fabric. Another polypropylene-based nonwoven material, referredto as spunbond/meltblown/spunbond, is from continuous, molten filaments that areformed by in-line melt spinning. Meltblown materials are similar in that theyare formed from a polymer by in-line melt spinning; however, the fibers arefiner and not continuous. The most popular of the nonwoven materials used ismade of a three-layer polypropylene material. It comes in a number of differentweights, each designed to accommodate a particular application. The two-layersare composed of long, continuous fibers that account for the fabric's strengthand abrasion resistance. The center layer consists of a dense mat of meltblownfibers that account for its effectiveness in resisting the penetration ofliquids and bacteria while permitting the penetration of steam to achievesterilization. These polymer disposable flat wraps are low-linting, soft to thetouch, and drapable.

Wrapper materials

Wrapper materials must incorporate the following guidelines:

  • Allow adequate air removal and steam penetration of the package contents.

  • Provide an adequate barrier to the penetration of microorganisms.

  • Provide an adequate barrier to fluids.

  • Resist tearing or puncturing.

  • Have proven seal integrity.

  • Allow for ease of aseptic presentation.

  • Be free of holes.

  • Be free of toxic ingredients and nonfast dyes.

  • Be low-linting.

  • Be shown to be cost-effective by value analysis.

There have been many studies on the maintenance of sterility or shelf-life ofa sterile package, most discussing whether time or events should be the bases ofdetermination. Several studies have confirmed the value of event-relatedpolicies. This practice reduces labor and supply costs. There are importantfactors to consider when incorporating event-related practices. Types ofwrapping or packaging materials used must be resistant enough to take abuse inhandling and resist tearing or puncturing. The type of storage (open or closedshelving) and storage area conditions must be monitored to assure stableenvironmental conditions such as temperature and humidity. Lastly, the personnelhandling the sterilized items must be educated to know proper handlingprocedures. Many healthcare facilities are converting to event-related sterilityversus the previous practice of expiration dating. In expiration dating, a loadsticker is placed on the package displaying the date the product was sterilizedand the load number. This is then used as a tool for controlling the facility'sinventory.

What CS Technicians Should Know About Wrapping

CStechnicians must have an understanding of how to properly select and apply thecorrect wrappers for the sterilization method chosen. The manufacturer anddistributors must be able to provide detailed specifications regarding theproperties of the product as well as documentation of acceptable results of itspast performances. Improper selection of materials and packaging application canand will impede the sterilizing process.

Technicians are also responsible for quality assurance issues. They mustassemble each package with care, being observant not to tear or damage thewrapper. Each package is uniquely organized, depending upon content, to promotethe sterilization process. Special attention must also be given to how thesterilizer is loaded.

There have been many improvements in the world of wrapping materials and, asalways in the field of Central Service, there is constant change happening allaround us. New sterilizing equipment results in new wrapping materials andimproved wrapping techniques. Healthcare professionals must be committed tostaying current regarding these technological improvements. Always remember thatpatients have put their trust in our hands.

Julie Stoller, CRCSD, works in the Central Processing Department as a casecart technician at Innovative Health Hospital, (Fargo, ND).

For a list of references, access the ICT Web site.