Shelf life of sterilized packaged items stored in acute care hospital settings: factors for consideration

Abstract

Reusable medical devices are sterilized and stored before their use in hospital settings. The length of time the sterilized item can be stored (shelf life) to maintain sterility has been discussed in the literature over the last four decades, with a shift to an event rather than time-related determination of shelf life. This paper reviews the evidence and provides a summary of some key issues for consideration when adopting event-related or time-based shelf life recommendations for packaged sterile items in Australian hospitals. Australian and international standards provide guidelines for procedures to be used for sterilization of reusable medical devices and storage conditions following sterilization. Reusable medical devices are sterilized by commercial manufacturers or sterilizing departments located in hospitals. Commercial manufacturers allocate expiry dates on sterilized items which should be respected, unless sterility is compromised by an event. The shelf life of items sterilized in hospital is debated, with growing support for event- rather than time-related sterility. Many factors determine whether event- or time-related shelf life should be followed. Well designed experimental studies into shelf life of sterilized items are lacking, with some small studies indicating that items can remain sterile for 12 to 24 months. Factors for consideration by hospitals are outlined and an algorithm to assist in implementation of event-related or time-based shelf life for reprocessed reusable medical devices is provided. The method of determining shelf life in hospitals is dependent on adequacy of processes for sterilization, monitoring of sterility over time and storage conditions.