Luer system

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Disposable syringe made of plastic with Luer lock connection ("male")

The Luer system is a standardized connection system for the combined use of syringes and infusion sets in the medical field. It is used, among other things, for cannulas , syringes , catheters , three-way stopcocks and infusion tubes . There is only one size with this connection system.

history

The name Luer goes back to the German instrument maker Hermann Wülfing Luer († 1883), who worked in Paris . The Luer connection combined with a rotation lock was first described in 1952. The spellings Luer-Lock for the connection with a fuse and Luer-Slip for those without a fuse are protected as registered trademarks of the Becton Dickinson company .

Until the Ramstein flight conference in 1988, infusion cannulas with a record cone were still widespread in Germany. These were subsequently replaced by those with a Luer cone in order to ensure compatibility between German and foreign rescue services in the future.

technology

The seal is achieved by a conical construction of the connecting parts, the so-called Luer cone . The inner cone of one connection side is also referred to as female , the outer cone of the opposite side as male . The Luer cone is a maximum of 7.5 mm long and typically 4 mm at the tip. The taper angle (included angle) is 3.44 ° (6%).

The simpler variant without a screw thread is called a Luer attachment , plug or slip .

If the male cone is provided with an internal thread to lock the connection, the system is called a Luer lock . This way the connection can be secured against accidental loosening, it closes and opens with half a turn.

The Luer system ensures compatibility between different manufacturers and is internationally standardized by the ISO - standard ISO 80369 and the German translation in the DIN available EN 80369-7.

advantages

  • quick and easy assembly, as it is a plug connection (Luer-Slip) or only half a turn is necessary without the use of tools (Luer-Lock). In addition, these are standardized parts that are only available in one size.

disadvantage

  • The Luer-Lock connection harbors dangerous mix-ups, as it is compatible for a wide variety of applications. It enables vascular (veins and arteries), spinal or peridural (spinal cord), enteral (e.g. feeding tubes) and respiratory (airways) applications. So it cannot be ruled out that z. B. a drug to be injected venously is mistakenly applied spinally (into the spinal cord fluid).
  • The Luer-Lock connection does not always close securely. In the case of poorly manufactured connectors, spontaneous openings of the connection are known, which z. B. with ongoing infusions can have fatal consequences. In addition, the connection can easily be released by anyone.
  • Conversely, there are often problems with over-tightened connections: If the Luer-Lock connection cannot be released by hand, an anatomical clamp is placed on the male connection part and the connection is twisted off. Such an instrument should therefore always be at hand (e.g. hanging on the IV pole)
  • In the case of existing Luer-Lock connections, contamination problems can arise, as every conscious or unconscious disconnection enables the introduction of pathogens. Therefore, the number of manipulations must be kept to a minimum. Necessary manipulations must be carried out under aseptic conditions, conscientiously carried out disinfection measures (hands, material).

literature

Individual evidence

  1. DIN EN ISO 80369-7. October 2017, accessed July 6, 2019 .