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Building a barrier to infectionBuilding a barrier to infection

Daphne Allen

December 9, 2015

6 Min Read
Building a barrier to infection

Specialty lidding played a critical role in preserving alcohol-saturated sponges in novel disinfection caps for central line catheter access valves.

Because central lines are catheters intended to deliver IV fluids for long periods of time directly into the vessels closest to the heart, patients with such catheter lines are at particular risk of infection. According to the CDC, about 250,000 central line-associated bloodstream infections (CLABSI) occur in U.S. hospitals each year with a mortality rate of 12‒22%.

Current infection-control protocols call for nurses to vigorously clean the luer access valve, or “scrub the hub,” for at least 15 seconds with alcohol prior to accessing an IV catheter, explains Chris Gardner, vice president of product development, for Excelsior Medical (Neptune, NJ; www.excelsiormedical.com). He says that compliance with this disinfection protocol is very low among nurses. Excelsior manufactures prefilled needleless syringes for flushing catheters, including a new line of syringes that were designed specifically to minimize syringe-related reflux.

Over one billion flush syringes are used each year in the United States, reports Gardner. SwabCaps can be used to disinfect central-line access valves for as long as they are intended to be used, says Gardner. In the United States, such valves can be used for up to four days. Infection-control procedures are critical when accessing IV catheters, notes Gardner. Alcohol-saturated preparation pads are typically used to clean valve surfaces, he reports. However, “numerous hospital-sponsored studies have found that the typical level of valve disinfection was inadequate, and nurses could actually be flushing contaminants into the bloodstream,” he says. “In addition, valves often have complex geometries, so there is some concern whether prep pads can reach all surfaces.”

In 2005, the company decided to explore new ways to protect patients from CLABSIs and began working on designs that resulted in the 2009 launch of SwabCap. The disposable cap covers a needleless connector of a luer access valve and features a built-in sponge containing 70% isopropyl alcohol as the disinfectant. “When the cap is secured to the connector, the sponge is depressed and bathes the valve with the IPA,” explains Gardner. “A thin membrane is deflected by the valve as the cap is applied, acting as a thread cover. The thread cover retains the alcohol under the cap and keeps it on the access site and threads of the needleless connector. Because the cap is intended to cover the site between accesses, it disinfects the site upon cap application, protects the site from additional contamination, and saves nurses time before the next access.” After line access, nurses apply a new SwabCap.

Packaging the alcohol

Identifying sufficient barrier materials to contain and preserve the 70% IPA was critical for product success. “We needed a lidding material with low permeability to seal to the contract-molded HDPE tubs that would be used to hold and deliver the SwabCap,” says Gardner. “In addition, we needed a lidding that could seal fast during automated assembly. And given the small size of the tub, we needed the lidding to peel easily and not be cumbersome for nurses to use.”

The lidding also needed to seal to the thermoplastic elastomer cap itself in order to preserve the alcohol-saturated sponge inside.

“Holding alcohol, particularly while sealing to dissimilar materials in a flexible-to-rigid peelable application, is a challenge,” explains Dhuanne Dodrill, president of Rollprint Packaging Products. Excelsior Medical chose to work with Rollprint, which offers a range of films with custom sealant technology.

“Alcohol has low surface tension, so it acts as a surfactant,” explains Dodrill. “For comparison, water has a surface tension of 73 dynes/cm, while a 100% alcohol solution has a low surface tension of 23 dynes/cm. That is less than packaging films and plastics, so alcohol tries to wick through them.”

Rollprint set out to develop a peelable film structure that would not weld-seal to either the tub or the cap. “The seal strength could not be so strong that it would pull the cap out of the tub upon peeling,” she explains. “The lidding has to peel from the tub and the cap with the same seal force. It has to be a consistent peel in order for the product to function correctly.”

The lidding also needed hot tack to be able to seal to HDPE, and it needed to be able to accommodate the alcohol vapor that would be created during heat sealing, she adds. “The lidding needed sheer strength to be able to withstand the alcohol vapor.”

Rollprint suggested a foil lamination featuring its Allegro B peelable sealant, and it met SwabCap’s barrier and sealing requirements. “It offers a consistent peel strength over a wide sealing window, and it is a forgiving material because it accommodates variations in temperature and pressure.”

Rollprint designed a polyester film extrusion-laminated to a 2-mil foil, which included a white extradate for inline printing and a clean appearance. It was then extrusion coated with Allegro B, Dodrill explains. It is supplied on rolls to accommodate Excelsior’s automated sealing procedures, which entails punching out/die-cutting the lid and sealing it to the HDPE tub, all taking place in-line in a cleanroom.

SwabCaps are sold in bulk in boxes of 200, bags of 25 for hanging on an IV pole, and copackaged with prefilled saline-flush syringes in flow-wrapped pouches. Excelsior also offers a newer syringe called SwabFlush, which incorporates a SwabCap into the end of the syringe’s plunger rod. “With SwabFlush, SwabCap is provided exactly where it’s needed, when it’s needed. This drives very high compliance with port disinfection. Nurses cannot forget to disinfect using this new design,” says Gardner. “When they push saline through the luer valve as their final step, they can then turn the syringe around, peel off the foil lid, and apply the cap to the valve.”

Patient outcomes

Gardner reports that recent hospital studies have shown that SwabCap improves site disinfection, leading to lower infection rates. According to the CDC, on average there are about two serious infections for every 1000 catheterized days. “Our customers have seen a decrease in infections by 50‒80%,” he says. “This is a profound impact.”

For instance, Doctors Hospital of Laredo, TX, reported an increase in compliance in cap utilization from 34% to 84% after switching from using the bulk packaged cap to using the copackaged kit, says Gardner. The hospital independently conducted a study in which they reported a 67% decrease in CLABSIs comparing 12 months prior to SwabCap implementation to the 9 months after SwabCap was introduced. Furthermore the hospital reported that they achieved zero CLABSIs in the 2nd and 4th quarters of 2011 while the copackaged configuration was in use,” added Gardner.

Also, NorthShore University Health System in Evanston IL, recently completed a four-hospital, 18-month study on the efficacy of SwabCap. The healthcare system measured colonization within the catheter and CLABSI rates before using SwapCap, after using SwabCap, and then again after taking away SwabCap. Publishing its results in the article “Continuous Passive Disinfection of Luer Access Valves to Prevent Contamination,” Northshore found a 47% reduction in the number of colonized catheters, a 75% reduction in the number of organisms present, and a 79% reduction in the number of infections, all from phase one to phase two of the study, reports Gardner.

“This product meets a distinct need right now for controlling hospital-acquired infections,” says Dodrill. “It is a huge focus, given Medicare’s requirements and insurance companies’ coverage restrictions. Hospitals are now responsible for paying for HAIs, so they are seeking effective solutions.”

About the Author(s)

Daphne Allen

Daphne Allen is editor-in-chief of Design News. She previously served as editor-in-chief of MD+DI and of Pharmaceutical & Medical Packaging News and also served as an editor for Packaging Digest. Daphne has covered design, manufacturing, packaging, labeling, and regulatory issues for more than 25 years.  Follow her on Twitter at @daphneallen and reach her at [email protected].

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