As ISO 80369 nears completion, medical device OEMs need to understand design and performance criteria for luer alternatives

Bob Michaels

April 27, 2011

8 Min Read
Small-Bore Connectors Find Their Perfect Mates

The proliferation of luers (left) prompted the development of ISO 80369, which requires the use of specified luer alternatives such as this one by Value Plastics (right).

Promoting patient safety is paramount in medical device design and development. But in the case of tubing connectors, the widespread use of compatible luers for various gas and liquid delivery systems has continued to put patients at risk of life-threatening tubing misconnections. In a global effort to dramatically reduce this risk, however, industry, suppliers, and regulatory agencies have come together to develop the ISO 80369 standard on small-bore connectors for liquids and gases in healthcare applications. And while the imminent approval of the standard's subsections signifies a long-overdue shift in patient care, it also represents a new era of medical device design for many OEMs.

Tubing Misconnections
Because of their ease of use, price, and reliability, tapered luers quickly became the tubing connector of choice in the late 1980s and 1990s. But this proliferation of luers across tubing sets and delivery systems designated for such different functions as enteral feeding, IV administration, and neuraxial access presented the opportunity for fatal tubing misconnections.

"There is not really a problem with luers or tubing connectors themselves," explains Bruce Williams, CEO of tubing connector supplier Value Plastics Inc. (Fort Collins, CO). "The difficulty comes from the fact that they work well and, since they are relatively inexpensive, they are used in many different, and sometimes incompatible, applications. Even though the application may be incompatible, the luer connectors mate with each other as the user expects them to and therefore don't provide an indication that the tubes they've just connected shouldn't be."

Leak-proof, biocompatible tubing connectors are available from Colder Products to replace luers in a range of medical device applications.

As a result of this universal compatibility and lack of error feedback, rushed nurses have inadvertently connected enteral feeding lines to IV catheters and IV lines to epidural lines, according to reports. "It really does put a nurse in a difficult situation," notes Jim Brown, business unit manager for medical markets at Colder Products Co. (St. Paul), a provider of quick-disconnect couplings, fittings, and connectors. "[The lines] all look virtually the same, and if you connect any of those incorrectly, you can cause an irreversible injury or death."

Scattered reports of such luer-related tubing misconnections prompted rumblings of change years ago, but the development of concrete, enforced guidelines has been slow to occur. As far back as 1996, the Association for the Advancement of Medical Instrumentation (AAMI) released a standard stating that connectors employed with enteral feeding tubes should not be able to mate with female luer-lock connectors. However, the standard was not strongly enforced and had little impact on tubing connector designs. Prior to and following that standard, the European Committee for Standardization actively discussed how best to prevent misconnections and experienced some success in influencing blood-pressure cuff design away from luer connectors.

"The Institute of Medicine's [1999] report, 'To Err is Human' was the watershed that kind of broke things open, however," says Brad Noe, manager, technical resources/marketing, at BD Medical (Franklin Lakes, NJ) and cochairman of the U.S. technical advisory group to Joint Working Group 4, which is responsible for developing ISO 80369.

Since then, regionalized efforts, the Joint Commission's 2006 Sentinel Alert, and coverage of tubing misconnections in the mainstream media have added fuel to the fire. The culmination of all this activity around 2006 and 2007, Noe says, spurred AAMI to develop a technical advisory group. "Then, it was decided to elevate this on a global basis," he recalls. "The EU efforts, the U.S., and a number of other member bodies within ISO came together and decided that this standard was what we're going to create."

The ISO 80369 Standard
"In a nutshell, the goal is to improve patient safety," Williams comments. "When complete, the standard will provide medical device manufacturers with guidelines to help ensure that the various tube sets used to administer different types of patient care cannot be accidentally connected to equipment, other tube sets, apparatus, etc., in such a way that the patient will be harmed."

ISO 80369 establishes criteria for small-bore connectors and tubing sets based on their application family. Released in January, the parent document, ISO 80369-1, summarizes the strategy and objectives of the subsequent subgroups in addition to identifying their requirements. "We recognized very early on that what is today's technology and solutions may be improved upon," Noe says. "We wanted to allow for latitude for someone building a better mousetrap to not have to go back and reinvent everything. There's consistency and synergies [in the parent document], but there are no restrictions as to what the design criteria could be except within certain tolerances and expectations."

Still in development, however, are ISO 80369-2 through ISO 80369-7. ISO 80369-2 focuses on connectors for breathing and driving gas applications while ISO 80369-3 sets forth the guidelines for enteral feeding connectors. In addition, ISO 80369-4 deals with connectors for urinary collection lines; ISO 80369-5 is dedicated to limb-cuff inflation systems; and ISO 80369-6 focuses on neuraxial use.

ISO 80369-7 states that vascular access in the form of IV lines is the only application family in which luers will still be permissible, however. "We [on the working groups] can all agree on two things," Brown says. "Something has to be done, and luers will be used only when going into the bloodstream; everyone else has to change to a different type of connector."

Though not yet approved, these subgroups are inching toward the finish line. Members anticipate that the documents will gain approval beginning later this year and continuing into 2012. "We're making what most people would think is a snail's pace progress," Noe notes. "But from an international standards emphasis, we're making tremendous progress in moving things forward to get to universal standards."

Luer Alternatives
In addition to the ISO 80369 standard, California legislation dictates that the state's acute-care facilities are not permitted to use interconnecting IV and enteral feeding sets as of January 1, 2013, or 24 months after the approval of the ISO standard--whichever comes first. Likewise, epidural connectors cannot mate with other sets as of January 1, 2014, or 36 months following standard approval.

"For U.S. manufacturers, which are also often global manufacturers, it's kind of a race here--a good one not a bad one--to have product available for consumption in California by that deadline or shortly thereafter," Noe notes. "It always helps to have an incentive."

To ensure compliance with this law and the ISO 80369 standard, medical device OEMs in the specified areas need to start educating themselves about the standard and planning for potential redesigns. "They should be aware of the [standard] so they can address potential issues now," Brown advises. "Ultimately, if you're a medical device manufacturer and you're using small-diameter tubing, you're going to have to look at your connector."

Clinical requirements, flow rates, air pressures, and other performance characteristics will be outlined in the ISO 80369 standard to guide OEMs in their tubing connector designs. Specified engineering controls or forcing functions will ensure that a tubing connector from one application family specified in the standard cannot mate with a connector from any other group, according to Noe.

"The standard will provide the OEM with information and connector designs specific to the applications referenced in the standard," Williams adds. "For example, if the OEM is designing a device for a respiratory application, the standard will provide a connector design that has been evaluated and determined to be suitable for that application. By utilizing the connector specified by the standard, the OEM will be assured that their device cannot be accidentally misconnected to the other applications referenced in the standard."

To assist with product design changes, suppliers such as Value Plastics and Colder offer a variety of tubing connectors and are working on new ones to accommodate the standard as well. Value Plastics notes that recommendations for specific application areas are premature because the ISO 80369 standard is still in development; however, the company offers an array of luer alternatives that includes the SBL, TSC tapered-seal, XQ quick-connect, and BPF blood-pressure connectors. The company is also developing unique connectors designed with sealing and latching features that do not mate with connectors discussed in the standard, according to Willliams. Furthermore, it has established an ISO 80369 news hub on its Web site that provides an overview, meeting notes, archived information, and the option to receive e-mail updates.

Similarly, Colder Products provides various tubing connectors for applications outlined in the standard as well as for other medical devices that can benefit from luer alternatives. For example, the company offers the SMC product line, a standard connector that will meet the specifications established in ISO 80369 for blood pressure cuffs. It also produces the SRC line, which was designed as a reliable, leak-free luer alternative and has been employed in blood-collection applications.

"Once the standard is released, it's a big task for manufacturers to change the connector system, make all the new tooling, implement it, and get rid of all of the old stock," Brown admits. "The standard is just the beginning of it."

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