Irish hospitals record substantial reduction in greenhouse emissions from inhaled anaesthetic gases

The HSE’s push to be cleaner and greener, and reduce the impact of healthcare on the climate, has seen a 27% reduction in emissions from inhaled anaesthetics in Irish hospitals. The work builds on the first national inventory survey of anaesthetic gas emissions. The inventory, conducted in 2019, estimated emissions at 17,865 tonnes of CO₂e.

Caring for the health of the environment goes hand in hand with caring for the health of patients and will support and protect the health and wellbeing of future generations.

In response, a multidisciplinary, national approach was adopted, involving collaboration between the College of Anaesthesiologists of Ireland (CAI) and the HSE. In 2024, emissions from inhaled anaesthetic agents used in public hospitals were 13,104 tonnes of CO₂e, representing a 27% reduction compared with 2019. These gases include Sevoflurane, Isoflurane, Desflurane, Nitrous Oxide, and Entonox, and are typically used for surgical anaesthesia and analgesia, labour analgesia, and procedural sedation.

Dr Ola Nordrum, Specialist Anaesthesiology Trainee and Climate and Sustainability Fellowship, HSE says; “The reduction in emissions is a really positive piece of work and highlights the collaborative efforts being taken across the healthcare sector to make our work cleaner and greener. It also indicates that Ireland is on track to achieve a 50% reduction in anaesthetic gas emissions by 2030, while maintaining safe, high-quality patient care, and demonstrates the impact of clinician-led action. Making healthcare more sustainable will benefit everybody and have a huge impact on our shared future.”

Dr Tim Keady, Consultant Anaesthesiologist and Lead for the College of Anaesthesiology in Ireland’s National Nitrous Oxide Mitigation Project, says; “Thanks to the commitment of dozens of volunteers, we have delivered measurable CO₂e reductions. Ensuring continued progress will depend on securing the necessary resources to support this work long term. CAI, through its Sustainability Committee, has led education, data sharing and changes in clinical practice to reduce emissions. This includes promoting lower-emission anaesthetic techniques, reducing the use of high-emission gases such as desflurane, increasing the use of low-flow anaesthesia, and encouraging regional and total intravenous techniques. CAI has also worked with the HSE Capital and Estates team to address nitrous oxide (N₂O) leaks from hospital piping systems and to decommission large manifold systems, helping to reduce waste and emissions.”

During the inventory phase, data was collected on inhaled anaesthetic agents used in all hospitals in Ireland. This was done by contacting hospital pharmacies for dispensing data on volatile agents (sevoflurane, isoflurane, and desflurane) and BOC Ltd, (Dublin, Ireland) for N2O and ENTONOX® (a ready-to-use medical gas mixture consisting of N2O 50% and oxygen 50% used for analgesia and sedation).