A Shelf - Life Trial : Examining the Efficacy of Event Related

This study set out to test the hypotheses that: 1) stock sterilised in a central sterilizing supply department using the guidelines from the Australian Standards (AS4187) will not become contaminated over two years unless it is exposed to an event; and, 2) a variety of packaging types can be used successfully in maintaining a sterile barrier over the two year trial period. A random controlled, time series, repeated measures design was used to test the hypotheses. Four hundred items were sterilised, wrapped in three different pack types, stored and regularly handled by nurses over a two-year period. Forty items were randomly selected for sterility testing each three months over the two years. The results showed that there was no contamination of stock over two years related either to time or the pack type used. Given that many nurses work in and manage CSSDs and many nurses use sterile stock in their work there are significant implications for nursing practice emanating from the findings. It was also calculated that the costs of meeting the Australian Standard AS4187 were reduced over the two year trial by up to 2400% by using event related sterility principles and an evidence based approach to the choice of packaging materials used in management of sterile stock. INTRODUCTION The stand alone central sterilising supply departments (CSSDs) of most hospitals in Australia have evolved historically from nurses’ work in operating theatres to include maintaining and improving the management of sterile stock (Taylor 1993). The gradual introduction of new standards and evidence based principles for the management of sterile stock since the early 1990s has major implications for nurses who work in CSSDs and those who use sterile stock in their practice. Current research supports the theory that contamination of sterilised stock is event related (Polzella and Holbeche 2002; Belkin 1996; Morall 1995; Taylor 1993; Butt et al 1991; Donovan et al 1991) and not, as it has been historically related, to time (Taylor 1993). The principle of event related sterility (ERS) is now considered as the Australian Standard (AS4187:55) for CSSDs. The standards suggest that contamination is related to features of the CSSD environment and/or the sterile storage area, wrapping materials, storage, handling and opening behaviours rather than just over time alone as has been the established principle. A review of published material by Taylor (1993) indicated there was little evidence to show the veracity of time related sterilisation (TRS) principles yet as Taylor (1993) notes hospitals have historically expended considerable resources in complying with this principle. According to Polzella and Holbeche (2002) and Taylor (1993) most Australian hospitals have applied a policy of 30-day stock rotation. That means every item is considered contaminated every 30 days even if sterility barriers are still intact. The calculation of costs associated with sterilisation must consider: stock management; stock depreciation resulting from wear and tear through the regular sterilisation process; labour; Robyn Barrett, RN, is Nursing Unit Manger, CSSD, St Vincent’s Hospital, Lismore, New South Wales, Australia John Stevens, RN, PhD, FRCNA, Joint Appointment School of Nursing and Health Care Practices, Southern Cross University and St Vincent’s Hospital, Lismore, and Director of the Collaborative Health Education Research Centre, New South Wales, Australia John Taranter, MAppSc(BioMed), BAppSc(Comput), MASM(USA), is a Senior Hospital Scientist, Microbiology, Northern Rivers Pathology Service, New South Wales, Australia Accepted for publication July 2003 A SHELF-LIFE TRIAL: EXAMINING THE EFFICACY OF EVENT RELATED STERILITY PRINCIPLES AND ITS IMPLICATIONS FOR NURSING PRACTICE