A better way to use steam sterilisers — saving money and water

Years ago, it took Forbes McGain only a few days of working as a doctor to realise that the environmental footprint (energy, waste, water) of even a medium-sized hospital was a thousand times that of an average household. It took him much longer to embark on trying to reduce hospitals’ large environmental footprint.

Life cycle assessment (LCA) (‘cradle to grave’ analysis) provides a scientific method of analysing the environmental effects of a process or item. These environmental effects include: energy use and CO₂ emissions, water use, fossil fuel and metal use, waste production etc. By gathering data about the resources used to manufacture and clean medical equipment one could begin to compare and contrast the environmental effects of different operations and processes.

With the assistance of Scott McAlister (a life cycle assessor) we began looking at the environmental and financial costs of common anaesthetic and ICU equipment, comparing re-usable and single-use items. We were finding that, contrary to the commonly held hospital staff belief, that re-usable equipment was considerably less expensive than single-use items (inclusive of the time to re-clean re-usable equipment by hospital staff), but that the environmental effects (particularly the carbon footprint) were similar in Australia between re-usable and single-use equipment.

The carbon footprint story is very different in Europe and the USA where a much greater proportion of electricity (particularly new electricity) is sourced from renewables (wind, solar) and natural gas, rather than coal. When comparing equipment your location (and thus energy source) really does matter. Living in Australia gives the worst-case scenario for re-usable equipment, because the electricity for your washers and sterilisers for re-usables is sourced from coal, compared to the single-use equipment which generally is made overseas using electricity less reliant on coal.

Case study

We discovered that steam sterilisation was responsible for the majority of the environmental footprint of re-usable equipment. So we dug further. We hooked up electricity and water meters and a Wi-Fi device to a Sunshine Hospital steam steriliser (Atherton’s Gorilla) and watched it for a year! We knew beforehand that each and every steriliser cycle used about the same electricity and twice as much water as an Australian 4-person household would use over 24 hours.

We were surprised; about 40% of all of the steam steriliser’s electricity use and 20% of the water use for the year was used in ‘standby’ (idle, not off). Since the idle periods consumed considerable electricity and water, efforts to ‘switch off’ become more important. Further, these idle periods were often of many hours’ duration, so switching off could still potentially avoid the pitfall of many steam steriliser ‘stop-starts’ (‘on-offs’). We also quantified the long-term electricity and water use of a hospital steriliser which will provide useful input data for future life cycle assessments of all re-usable, steam-sterilised equipment. More than half of a steam steriliser’s electricity and water use was required just to run a steriliser cycle, so unsurprisingly, large loads were more energy and water efficient than small loads.

McGain F et al. Steam sterilisation’s energy and water footprint. Australian Health Review. CSIRO Publishing. 14 Apr 2016.

The first simple steps we took to improve steriliser efficiency was to rotate off idle sterilisers and reduce the number of ‘light’ steriliser loads. This simple effort that cost nothing saved Western Health about $15,000 per annum, and 10 houses of electricity and water use. We also suggest that sterile supply department staff (so integral in all of our studies) found that their work became more efficient also as less time was required to be checking, performing test runs and loading the sterilisers. Importantly, there was no change to the number of operations performed per annum, nor was there any alteration in the hospital’s infection prevention policies nor quality assurance concerns.

There is so much more to do!

There is more to do at our hospital to improve steam steriliser efficiencies, more hospital electricity could be sourced from renewables, more is actually happening at the Atherton manufacturing facility in Melbourne to build efficient sterilisers, and there are more ongoing efforts by Scancare Queensland to provide software for theatre staff about steriliser efficiency. Most importantly, other hospitals could use our methods to examine steam sterilisers and many other energy-intensive items of hospital equipment so that healthcare “walks lightly so we can all walk on”.

Acknowledgements

I collaborated with Associate Professors Jim Black and Graham Moore of the University of Melbourne on these steam steriliser projects. We thank the staff of the Sunshine Hospital Sterile Supply Department, including Karen Tricker, Carlos Paciocco and Nancy Trujillo. We are grateful for collaboration with Scancare staff (Nathaniel Vann and Dion Purnell) and Atherton’s staff (particularly Sean Boston, Martin Harrison and Scott Lipman).

Forbes McGain has been an anaesthetist and intensive care physician at Western Health this past decade. He has recently completed a PhD in the field of hospital environmental sustainability. He remains keenly involved in medical research and education.

Main image caption: The Sunshine Hospital central sterilisation and supply department team.