After a 20-year effort to establish standards which would minimize the risk of medical misconnections, the pending release of the ISO 80369 series of standards has now reached a point of critical mass, shifting from a development stage to an implementation stage. The new series of standards is destined to change small bore tubing connector designs globally.

The Lure of the Luer

Fig. 1 – The history and broad use of luers stretches back nearly 120 years.

To do or not to do, that becomes the timing question with standards changes. What impact does a change have on your product design decisions and when? The pending release of ISO 80369 raises the question for designers using small bore connectors.

Small bore connectors are components used to connect medical devices to tubing and accessories that deliver fluids and gases to patients. Small bore refers to the size of the opening of the connector (less than 8.5 mm). The most commonly used small bore connectors are luer connectors, also called luer fittings or luers. (See Figure 1)

There are two types of luer connectors: slips and locks. A slip luer consists of a tapered male tip and wider-tapered female port that slide into one another and are held together with simple friction. A luer lock has an additional thread locking sleeves on each half to secure the two halves of the connection together.

Fig. 2 – Luers gained widespread use due to their adaptability.
Luer connectors present a simple, universal design that provides an acceptable connection for many uses. (See Figure 2) Their widespread use in diverse patient care applications permit connection between unrelated patient delivery systems with different intended uses. Patients might be connected to multiple medical devices. (See Figure 3)

These different devices access different points in the body providing different fluids or treatments:

  • Vascular: access into the bloodstream
  • Enteral: access into the stomach
  • Respiratory: breathing gases for the airway
  • Epidural: access into the spine
  • Limb Cuff: gases driven to provide pressure to a cuff, such as a blood pressure cuff

Fig. 3 – Today’s medical settings expose potential misconnections; ISO 80369 seeks to control them.
Luer’s universality of application, coupled with the escalation in the number of tubes and connections in medical laboratories, hospital rooms, and operating rooms increases the danger of inadvertent misconnection of wrong systems by health care providers. Such misconnections can cause medication, liquid feeding formulas, or air to be delivered through the wrong tubing to the wrong point in the patient. These errors have resulted in patient injury and death. The U.S. Food and Drug Administration (FDA) has received reports of serious and even fatal misconnections, as has the Institute for Safe Medication Practices (ISMP), The Joint Commission (TJC), the United States Pharmacopeia, and the ECRI Institute. Efforts to mitigate the problem, such as employing color-coded connectors and awareness training, have not proven successful in eliminating the problem.

Developing ISO 80369

To effectively address the issue, small bore connector designs needed to change. However, without a coordinated effort to create dimensionally unique connectors for different applications, preventing misconnection would be difficult to achieve. This initiative to develop a series of unique small bore connectors was first set in motion in Europe in the late 1990s. (See Figure 4)

Fig. 4 – Luer use will be more controlled and defined with ISO 80369.
In 2000, The European Committee for Standardization (CEN) formed a committee to specifically address this issue. The committee created definitions and a framework for the standards by evaluating the different medical applications and products using luers. The committee then reviewed these applications by the risk associated with the potential for a misconnection. This framework is still in use today.