Original research
Limitations As with any life cycle assessment system boundaries must be set and made clear at the outset, the quality of the data needs to be measured and any assumptions or limitations defined. Data cannot always be obtained from manufacturers so that best estimates must be used, and this methodology is both time consuming and costly. This was most evident for the manufac- ture of methoxyflurane as no data existed for it in Ecoinvent. The reactions required to make methoxyflurane were assumed according to the best available information online. We also assumed energy consumption in the filling and capping elements of production. The best available information online for this was sourced. The assumption that patients will use Penthrox with perfect technique is unlikely to be true in all cases. Patients using the device are likely to be in pain or distress and remembering to exhale back into the device in these conditions is question- able. Finally, the assumption that all material was incinerated was anecdotal evidence from our own experience working in healthcare. This type of detailed LCIA is now considered to be the industry standard and although it is laborious and by no means perfect, it is a far superior methodology to other so-called ‘carbon foot- prints’ as these only focus on one environmental impact category, the greenhouse gas emissions. An LCIA can take into account other impact categories such as land use, water use and ocean acidification. As such, a carbon footprint is only part of the full LCIA. The International Organisation for Standardisation (ISO) has provided guidelines and requirements for conducting an LCIA through ISO 14040 and ISO 14044. 28 29 The challenge for healthcare generally is to incorporate these standards into our efforts to reach net zero as they provide the best quality data by which to make and monitor changes to our practice. At present, too many healthcare studies do not provide the full picture of environmental impact for our pathways and processes. CONCLUSION As the effects of climate change become more apparent, the need to make healthcare sustainable become increasingly urgent. If the NHS is to reach its ambitious target of an 80% reduction in carbon emissions by 2032, then healthcare professionals must start making choices on the drugs and equipment that they use, based on rigorous scientific evidence such as that presented in this study. This study has shown that low-dose methoxyflurane and morphine are more sustainable in terms of their relative climate change impact compared with N 2 O. Therefore, the authors urge readers to consider using methoxyflurane or morphine rather than N 2 O if it is safe to do so. Contributors AM led the project, collected and analysed the data and drafted and revised the paper. He is guarantor. DM initiated the collaborative project and drafted and revised the paper. TC drafted and revised the paper. AF-W assisted with data analysis and drafted and revised the paper. BD assisted with data collection tools and data analysis, drafting and revision of the paper. The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted. Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors. Competing interests None declared. Patient consent for publication Not applicable. Ethics approval Not applicable. Provenance and peer review Commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request. Complete input/output flows for OpenLCA can be found in online supplemental appendix 3. Raw data output from OpenLCA have not been submitted to the journal and can be made available on reasonable request. Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise. ORCID iDs REFERENCES 1 Romanello M, McGushin A, Di Napoli C, et al . The 2021 report of the lancet countdown on health and climate change: code red for a healthy future. Lancet 2021;398:1619–62. 2 UK Government. Climate change act 2008. 2008. Available: https://www.legislation. gov.uk/ukpga/2008/27/contents 3 United Nations. Paris agreement to the United Nations framework convention on climate change . 2015. 4 Legislation.gov.uk. Health and care act 2022. UK public Gen acts 2022;C.31:section 186. n.d. Available: https://www.legislation.gov.uk/ukpga/2022/31/section/186# section-186-4 5 Tennison I, Roschnik S, Ashby B, et al . Health care’s response to climate change: a carbon footprint assessment of the NHS in England. Lancet Planet Health 2021;5:e84–92. Aleksis EV Martindale http://orcid.org/0000-0003-3552-6945 Amarantha Fennell-Wells http://orcid.org/0009-0009-2412-1708 Brett Duane http://orcid.org/0000-0001-9670-0594 6 The NHS Net Zero Expert Panel. Delivering a ‘Net Zero’ National Health Service . NHS, 2020: 12. Available: https://www.england.nhs.uk/greenernhs/wp-content/uploads/ sites/51/2020/10/delivering-a-net-zero-national-health-service.pdf 7 Spruell T, Webb H, Steley Z, et al . Environmentally sustainable emergency medicine. Emerg Med J 2021;38:315–8. 8 Babl FE, Jamison SR, Spicer M, et al . Inhaled methoxyflurane as a prehospital analgesic in children. Emerg Med Australas 2006;18:404–10. 9 Mercadante S, Voza A, Serra S, et al . Analgesic efficacy, practicality and safety of inhaled methoxyflurane versus standard analgesic treatment for acute trauma pain in the emergency setting: a randomised, open-label, active-controlled, multicentre trial in Italy (MEDITA). Adv Ther 2019;36:3030–46. 10 International Panel on Climate Change. Ar5 synthesis report: climate change. 2014. Available: https://www.ipcc.ch/report/ar5/syr [Accessed 16 Aug 2023]. 11 Wernet G, Bauer C, Steubing B, et al . The ecoinvent database version 3 (part I): overview and methodology. Int J Life Cycle Assess 2016;21:1218–30. 12 Hildenbrand J, Srocka M, Ciroth A. Openlca 2.0.0. 2018. Available: https://openlca.org 13 National Center for Biotechnology Information. Pubchem compound summary for CID 6427, 1,1,2,2-Tetrachloro-1,2-Difluoroethane. n.d. Available: https://pubchem.ncbi. nlm.nih.gov/compound/1_1_2_2-Tetrachloro-1_2-difluoroethane#section=Methods- of-Manufacturing 14 Sauer J. 1,1-Dichloro-2,2-Difluoroethylene. Org Synth 1956;36:19. 15 National Center for Biotechnology Information. Pubchem compound summary for CID 4116, Methoxyflurane. 2023. Available: https://pubchem.ncbi.nlm.nih.gov/compound/ Methoxyflurane#section=Use-Classification 16 Nevitt S, Shephard M. Personal communcation with manufacturer. 2022. 17 Osterroth IA, Voigt T. Energy consumption of beverage-bottling machines. Sustainability 2021;13:9880. 18 Ports.com. Sea route & distance. 2013. Available: http://ports.com/sea-route/ 19 Google. Google maps. 2023. Available: www.googlemaps.com 20 Yoshimura N, Holaday DA, Fiserova-Bergerova V. Metabolism of methoxyflurane in man. Anesthesiology 1976;44:372–9. 21 Pearson F, Sheridan N, Pierce JMT. Estimate of the total carbon footprint and component carbon sources of different modes of labour analgesia. Anaesthesia 2022;77:486–8. 22 McAlister S, Ou Y, Neff E, et al . The environmental footprint of morphine: a life cycle assessment from opium poppy farming to the packaged drug. BMJ Open 2016;6:e013302. 23 HaCon Ingenieurgesellschaft. Ecopassenger. 2023. Available: https://ecopassenger. hafas.de/bin/query.exe/en?L=vs_uic&protocol=https%3A&newrequest=yes 24 Rahman SM, Quinn E. BET 1: green or blue for you? Methoxyflurane (Penthrox) or nitrous oxide/oxygen 50% mixture (Entonox) for the management of acute pain in the ED. Emerg Med J 2019;36:506–8. 25 Seglenieks R, Wong A, Pearson F, et al . Discrepancy between procurement and clinical use of nitrous oxide: waste not, want not. Br J Anaesth 2022;128:e32–4.
Martindale AEV, et al . Emerg Med J 2024; 41 :69–75. doi:10.1136/emermed-2022-213042
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