Small-bore connectors, which have an opening size of less than 8.5 mm, are essential components in various medical devices used to transfer fluids and gases to patients. Historically, luer connectors were widely adopted for intravascular applications, though they were often used for other medical purposes as well. Luer connectors come in two types: the luer slip connector and the luer lock connector.
As part of regulatory updates, 6% luer connectors are now exclusively designated for intravascular and hypodermic use. These connectors were originally standardized under ISO 594, with Part 1 covering general requirements and Part 2 specifically addressing luer lock fittings.
The challenge of use-errors with Luer Connectors
As luer connectors have been adapted for a variety of applications—such as vascular, enteral, and respiratory uses—there have been instances where different devices with unique purposes have been inadvertently connected, leading to serious and sometimes fatal errors. The US FDA has published several case studies to highlight the possibility of such use errors (source: https://www.fda.gov/medical-devices/medical-device-connectors/examples-medical-device-misconnections).
Epidural tubing erroneously connected to IV tubing
IV tubing erroneously connected to nebuliser
IV tubing erroneously connected to enteral feeding tube
These instances underscore the need for distinct connector standards to minimize the likelihood of misconnections.
The Role of ISO 80369 Standards
The ISO 80369 standards were developed to address and mitigate these risks. Introduced in 2011, Part 1 of the standard outlines the general requirements for small-bore connectors used in healthcare settings. It also provides a testing framework to ensure that unrelated delivery systems cannot be mistakenly connected. Part 20 specifies the common test methods, while Parts 2 through 7 apply to specific applications (with Part 4 yet to be published).
Key Differences and Specifications
ISO 80369 standards set forth precise dimensional requirements and material properties to prevent misconnections.
The material properties are aimed at preventing force-fits of non-mating connectors.
Compliance with ISO 80369
To demonstrate compliance, connectors must meet specific material and dimensional requirements, undergo non-interconnectability testing, and satisfy performance criteria. ISO 80369-1 mandates that small-bore connectors within each application category should not be compatible with connectors from other categories, with a two-method approach available for interconnectability testing.
The following performance tests are recommended on ISO80369 connectors:
Not all tests are mandatory for all types of connectors.
Interconnectability Testing
ISO80369-1 states that small-bore connectors of each application category shall be non-interconnectable with any of the small-bore connectors of every other application category, unless otherwise indicated in ISO 80369-1 or within the ISO 80369 series.
There are two stages to prove interconnectability.
Regulatory Recognition of ISO 80369
Since December 2023, the FDA has ceased recognition of the ISO 594 standard, endorsing ISO 80369-7 for luer connectors instead. In Europe, earlier versions of the luer connector standards were withdrawn as of May 2020, with ISO 80369 now being the accepted standard for new submissions.
ENFit™: The New Standard for Enteral Connectors
ENFit is the trade name of the new enteral standard connector compliant with ISO 80369-3, in the female to male orientation. ENFit was developed by an international team of clinicians, manufacturers, and the FDA
The road to full adoption
Despite the clear benefits, the transition to ISO 80369-compliant connectors has been gradual. This is largely due to the substantial costs associated with redesigning connectors, updating tooling, and managing existing inventories of legacy products.
In conclusion, while the ISO 80369 standards represent a significant advancement in patient safety, their widespread adoption remains a work in progress. With continued industry efforts, these standards will ultimately help minimize risks associated with medical misconnections.
