Wrap vs. containers study prompts dialogue, questions among industry thought leaders

Sept. 19, 2016

A recent scientific study,1 funded by Halyard Health and published in the American Journal of Infection Control, on the effectiveness of rigid containers versus wrapped instrument trays in protecting instruments from contamination has generated much dialogue — and many questions. Researchers found 87 percent of the rigid sterilization containers tested did not maintain sterility through transport and handling, compared with 100 percent of the wrapped trays. Below are comments on the study’s findings from both CS/SPD professionals, and wrap and container manufacturers. 

Mark Duro

Mark Duro, Director of Sterile Processing Operations for New England Baptist Hospital in Boston

“When I first saw this study I had a lot of questions about it,” said Duro. “I find it interesting that in the study most containers failed and wrap did not and it makes me question the testing methods used. When I looked at the PSI of the pressures they used, I question what relevance that has to our world. I don’t know if it ties directly into real-world events. Door swing can create pressure, being on an elevator can increase pressure and coming out of a sterilizer can create pressure but is it equivalent of what they did in the study? The testing methods were a little confusing to me.”

“As a CS Director, it is up to the objectivity of the person reading this study to decide how they will use the findings,” added Duro. “If the severity of the study was as horrific as it looks in the study I think I would have some major infection control issues. So I’m not going to pull all of my containers out of circulation because of that. I think the study is interesting but don’t think containers are really an issue.”

“Coming out of this study I reminded my technicians to inspect the containers thoroughly as they assemble them,” said Duro. “And we have scheduled preventative maintenance with our vendor. Some people have a hard time with maintenance because there are so many parts. When our vendor does its refurbishment, it puts on the part the date it was done so I can keep tabs on when a particular container part must be reevaluated by the manufacturer. The key is to make sure containers are properly maintained so they provide an effective barrier.”

Marcia Frieze

Marcia Frieze, CEO, Case Medical

“In response to the Halyard study, this is an example of how science can be inappropriately used for marketing purposes. In their most recent published study, Halyard exaggerated their claims for sterility maintenance by using ‘brand new’ wrap in multiple layers, and primarily used containers challenged by a microorganism that is smaller than the pores of their own filter material. Not all containers are the same. While some containers have no gasket or offset between the vented area and the filter retention plate, Case Medical has an offset vent pattern and a gasketed filter retention plate. Also our container is designed with a knife-edge fit. The recessed gasket in the lid creates a pathway that microorganisms cannot navigate as they cannot turn corners or navigate a maze.”

“The Halyard study does not represent any guidance document as it was originally designed for face masks under less strenuous conditions,” Frieze added. “Further, the containers tested were subjected to over 10 years of microbial contamination aerosolized under pressure in a 70 minute study. In no way does this particular study represent a real world challenge to a sterilized package. No one in the industry recommends that a container be stored for over 10 years anyway and it is commonly known that any package, containerized or wrapped, must be reprocessed when moisture is present”

“In addition, there are so many opportunities for human error in handling and aseptic removal with this type of study,” Frieze continued. “For example, how the outer surface was decontaminated (in this case with a disinfecting wipe without rinsing off residue). In a previous study spores were used that cannot even be killed by disinfectants. How the contents were aseptically removed, if gloves or PPE were changed between steps. The type and size of the microorganism used (micro-coccus luteus) in this study is a microscopic bacteria which is commonly found in the air, on clothing and on hands. Furthermore, Halyard forgot to test worn wrappers, or maybe it was intentional.”

Ed Nuber

Ed Nuber, Group Product Director, Central Sterile Products & Services, Aesculap

“When you looked at the study and the fact that new containers failed, I think you need to look at the technique and objectivity of the study itself,” said Nuber. “Containers are a FDA Class 2 device and aerosol validation testing is part of the FDA 510(k) submission package. “Also containers are part of your surgical assets within a hospital. They need to be maintained properly and should be inspected prior to use and be repaired as needed. They need to be inspected just like wrap needs to be inspected as well. The wrap that was used in the study was new wrap, as all wrap is. It was used to wrap the set and placed in plastic bags and moved to an outside facility for sterilization. So it didn’t experience the full spectrum of how it is used in the hospital. You would sterilize it, handle it by the sterile barrier, place it on a cart, store it and dust would settle on it. That’s the real world.”

“The Aesculap container system works in the real world,” he continued. “Users have been converting from wrap to containers for years and the rate is increasing. The reason is simple. More real world experience with wrap — holes in the wrap cause case delays and cost the facility money and OR time. Holes in the wrap can lead to a contaminated instrument set and may lead to patient infections. That’s the real world and why there are wrap to container conversions happening across the country.”

“Another thing to consider is that both containers and wrap need to be inspected at point of use,” Nuber added. “Containers are inspected by inspecting the filter. Wrap needs to be inspected for holes, tears and abrasions. If you think of the size of an instrument set in a hospital, most trays are full sized, which means the wrap used can be 48” x 48” or 54” x 54” square. That’s over 16 square feet that needs to get inspected by the OR personnel. That is approximately the size of your kitchen table. There’s a study that was published in 20072 where holes approximately the size of a pencil (6.7 mm) in sterile wrap were missed 18 percent of the time during inspections. Containers and wrap need to be inspected in the OR prior to use. The facility should ensure inspection policies and procedures, based on the manufacturer’s IFU, are in place and the staff is properly trained.”

Rose Seavey

Rose Seavey, Owner of Seavey Healthcare Consulting, LLC

“Instrument storage is a huge part of sterilization and key to preventing surgical site infections,” said Seavey. “We can’t do things the way we’ve always done them and now we have evidence out there that we really need to think about whether we are doing the best thing for sterility. Sterility is an art and a science, and in this day and age, we have to make sure we are following the science and doing things artfully because it’s not just slapping things together.”

“The standards leave it up to the user to make sure everything is intact but we as users don’t always take the time to evaluate the products as much as we should,” added Seavey. “With wrap we are routinely looking for holes, rips or worn spots. With containers some people may automatically assume they are fine because they are solid boxes, as long as the filters are OK. I believe most people don’t take the time to look at the integrity of the container. Are there any dents in the box or lid, are all the gaskets intact on the lid and the retention plates, do you have the right lid, basket and retention plate according to the manufacturer’s IFU? If you look at the IFUs for many of the containers you’ll see they require preventative maintenance and a warranty for so many years.  I wonder how many facilities actually follow and track that information.”

“I encourage everyone to watch the video3 of the expert roundtable discussing this study,” said Seavey. “I was skeptical of the study at first but when I got into it and spoke directly many times to the independent company that conducted it, it became clear that we need to do more around ensuring sterile storage. My recommendation is that container manufacturers conduct a similar study and compare the results.”

Lon Taylor

Lon Taylor, Director of Marketing, Surgical & Infection Prevention, Halyard Health

“Interestingly, this was the second study in a decade to report this finding, and yet, it’s not something that is often taken into consideration when identifying new potential causes of infection. It’s important that these statistics become a part of the discussion surrounding which type of sterilization packaging systems hospitals should be using in order to reduce the potential for SSIs, thereby improving patient outcomes and increasing hospital safety.”

“As one of the authors of the consensus statement on the study, infection preventionist Peg Luebbert, MS, CIC, CHSP, CBSPDT, has noted time and time again, facilities should conduct regular risk assessments of their rigid containers and may want to consider replacing older rigid sterilization containers with sterilization wrap,” said Taylor. “The science clearly demonstrates that sterilization wrapped trays are significantly more effective at maintaining sterility of their contents. Infection preventionists should also examine infection rates for different departments handling patients with high risk for infection. Serious consideration should be made to replace rigid sterilization containers with wraps, particularly if other measures have not succeeded in reducing infection rates.”


1. Harry L. Shaffer MS†, Delbert A. Harnish MS†, Michael McDonald MS, Reid A. Vernon BS, Brian K. Heimbuch MS†. Sterility maintenance study: Dynamic evaluation of sterilized rigid containers and wrapped instrument trays to prevent bacterial ingress. Am J Infect Control. 2015 Dec;43(12)1336—1341. http://www.ajicjournal.org/article/S0196-6553(15)00761-0/abstract.

2. Waked WR1, Simpson AK, Miller CP, Magit DP, Grauer JN. Sterilization wrap inspections do not adequately evaluate instrument sterility. Clin Orthop Relat Res. 2007 Sep;462:207-11.

3. http://www.halyardhealth.com/info/sterile-wrap-vs-rigid-containers.aspx.

About the Author

Kara Nadeau | Senior Contributing Editor

Kara Nadeau is Sterile Processing Editor for Healthcare Purchasing News.

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