Reducing the carbon footprint and cost of trauma theatres by correct waste segregation

By Matthew Smitheman^a, Catrin Morgan^b and Lily Li^c
aCore Surgical Trainee, Royal Surrey County Hospital NHS Foundation Trust
^bSpecialty Registrar in Trauma and Orthopaedic Surgery, Chelsea and Westminster Hospital NHS Foundation Trust
^cHand and Wrist Consultant in Trauma & Orthopaedics, Imperial College Healthcare NHS Trust

Croatia is not a country that usually springs to mind on mention of NHS England - sunny coastlines and towering mountain ranges drive a stark contrast to LED theatre lamps and single storey community medical centres. However they are linked by one inextricable number – the annual carbon footprint – where NHS England is equivalent to the Adriatic nation of almost four million people^1,2.

NHS England accounts for 4.6% of the UK’s total carbon footprint and approximately 25% of the public sector’s footprint^1,3. In the NHS, operating theatres have a disproportionate environmental impact because of their energy-intensive processes, consumption of resources, use of volatile anaesthetic agents, and production of waste. Theatres are estimated to be three to six times more energy-intensive than clinical wards, and tend to produce approximately 50–70% of the total hospital waste^4,5.

Operating theatre waste is typically segregated into four different steams: orange (infectious clinical), tiger (non-infectious clinical), green (recycling) and clear (domestic). These streams each have different disposal methods and costs, leading to varying amounts of CO₂ emissions.

Across two orthopaedic trauma theatres at St Mary’s Hospital (Imperial College Healthcare NHS Trust), a Level 1 Major Trauma Centre in central London, our team set out to assess correct waste segregation, quantify the recyclability of trauma theatre waste, and reduce the overall cost and carbon emissions. Firstly we mapped bin provision across the theatres, measuring the output of each waste stream using digital weighing scales, bag counts and spot checks to identify improper waste disposal. Next we calculated the cost of waste disposal and CO₂ emissions. We also distributed a waste segregation survey to all theatre staff members to ascertain behavioural trends and baseline knowledge.

The main issue that we addressed was the over-use of infectious (orange) clinical waste bags. Next time you are in theatre, take a look around – is your department using infectious waste bags (usually orange) for non-infectious cases? If the answer is yes, then this could be resulting in unnecessary cost and carbon emissions for your hospital. Orange bags should only be used for infectious cases (for example MRSA +ve, COVID-19+ve, CPE +ve).

Our survey showed that only 8% of theatre staff were able to correctly identify all waste streams. We distributed information on correct allocation of waste and an educational presentation was given at a local audit meeting. We modified bin provision and disposal streams across two theatres to better reflect the type of waste produced in each area of theatre. Orange infectious waste bags were replaced with tiger non-infectious waste bags for all non-infections cases. Information posters were placed throughout trauma theatres in easy-to-see places next to waste bins to give clear instructions on correct waste disposal.

As a result of the above, we reduced waste placed in the wrong stream by 74.7% - resulting in a 57.1% (£0.20/kg) cost reduction of waste disposal as well as a 28.9% (0.13kgCO₂e) reduction in CO₂ emissions. This can be extrapolated to a saving of just under a tonne of CO₂ emissions per theatre per year, which is the equivalent of driving 5000 miles in an average gasoline-powered passenger vehicle⁶.

However, this bottom-up approach can only go so far to address NHS emissions – less than 10% of theatre waste by weight was recyclable, regardless of the actions and good intentions of those using it. Simple proactive measures focusing on staff education and correct waste stream segregation can lead to a reduction in the carbon footprint and an overall cost saving for the NHS. However, given that CO₂ emissions from the manufacture and usage of NHS medical equipment is over six times greater than from waste products¹, a top-down approach needs to be adopted to produce long-term meaningful change.

References

1. Naylor C, Appleby J. Sustainable Health and Social Care: Connecting environmental and financial performance. The King’s Fund, 2012.
2. Branco A, Guizzardi D, Jacome Felix Oom D, et al. Emissions Database for Global Atmospheric Research, version v8.0_FT_2022. European Commission, Joint Research Centre (JRC) [Dataset] PID: http://data.europa.eu/89h/809d7b72-55ef-4e52-8bd4-7d33f2f9916b.
3. NHS England. Greener NHS.  Available at: www.england.nhs.uk/greenernhs. (Accessed 8 February 2023).
4. Guetter CR, Williams BJ, Slama E, et al. Greening the operating room. Am J Surg. 2018;216:683-8.
5. Yates EF, Bowder AN, Roa L, et al. Empowering surgeons, anesthesiologists, and obstetricians to incorporate environmental sustainability in the operating room. Ann Surg. 2021;273:1108-14.
6. Edenseven. What does a tonne of CO2 look like? Available at: www.edenseven.co.uk/what-does-a-tonne-of-co2-look-like. (Accessed 20 September 2023).