By Jason Pope, Senior Scientist
The AAMI Sterilization Standards Week was held in Baltimore MD in March of 2017. This set of meetings provides the opportunity for the various AAMI sterilization standards working groups to come together and provide input on numerous industry standards and guidance documents that relate to the sterilization of medical devices. One of the groups that had the opportunity to meet was ST/WG 43 – Hospital Steam Sterilizer Working Group.
During the meeting of ST/WG 43, a discussion occurred relating to the drying times recommended for healthcare steam sterilizers and the drying times listed by medical device manufacturers for device sterilization instructions. The drying times from sterilizer manufacturers are listed in the FDA Guidance Document for reprocessing of medical devices in health care settings and in AAMI TIR12. Representatives of multiple sterilizer manufacturers were involved in the discussion and expressed a desire to change the way the documents list the drying times for steam cycles that are commonly available in healthcare settings.
Sterilizer manufacturers explained that the listed drying times was determined by sterilizer manufacturers for specific loads, devices, and test packs used in sterilizer development and validation. The idea that the drying times, listed in the aforementioned documents, should be considered by medical device manufacturers as minimum times was discussed, with working group members indicating that medical device manufacturers may find that longer drying times are appropriate for their products during validation testing.
Several working group members expressed concern that the drying times listed in the FDA guidance document and AAMI TIR12 are being interpreted by medical device manufacturers and healthcare workers as being exact values that may not be lengthened. Discussion participants indicated that this interpretation of listed drying times is concerning if specific medical devices and loading configurations require longer drying times to ensure adequate moisture removal for device storage stability.
Nelson Laboratories has observed that the US FDA has cleared medical device submissions with drying times that exceed those listed in the FDA guidance document and AAMI TIR12. The drying time that a manufacturer includes in their device sterilization instructions should match the drying time determined by validation testing. It is impossible for sterilizer manufacturers to perform validation testing of a steam sterilizer in a manner that encompasses all current and future device types used in a healthcare setting to care for patients. A medical device design may have characteristics that require the drying to exceed the minimum drying times outlined by sterilization manufacturers.
Due to the removal of commonly available steam sterilization cycles from the most current revision of ANSI/AAMI ST79, a desire was expressed in ST/WG 43 to add the cycle tables to ANSI/AAMI ST8 – Hospital Steam Sterilizers. Many working group members expressed the opinion that this document, written for sterilizer manufacturers, was a good home for this cycle information. Many members felt that the addition of this information to ST8 should be accompanied by verbiage clarifying that the listed drying times are to be considered minimum times, the goal being to prevent medical device manufacturers and healthcare personnel from misinterpreting the drying time information to be unalterable and to help them recognize that longer drying times may be needed for specific device types and sterilizer loads. Additionally, clarifying verbiage will let device manufacturers and end users know that drying times should never be shortened from the minimum listed times.
The Hospital Steam Sterilizer Working Group recently decided to revise AAMI ST8 and plans to meet in the Fall of 2017. Nelson Laboratories will have a representative in attendance at that meeting and will be providing updates after the meeting is held in Baltimore.
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