CVS Equine Referral Hospitals Deliver Major Cuts in Isoflurane Use and Carbon Emissions

CVS Equine referral hospitals have achieved significant reductions in isoflurane consumption and associated greenhouse gas (GHG) emissions, marking a major step towards greener veterinary care. The initiative, led by Luís Filipe Louro, EBVS Specialist in Veterinary Anaesthesia and Analgesia at CVS Chestergates Veterinary Specialists, was implemented across five CVS equine referral hospital sites.

Isoflurane, widely used in equine surgery, is a potent GHG with a global warming potential hundreds of times greater than carbon dioxide. Recognising its environmental impact, CVS Equine set out to audit and reduce anaesthetic gas use, aiming to minimise emissions without compromising patient safety.

A structured multicentre clinical audit was conducted, analysing 414 general anaesthetic procedures across five hospitals between June-September 2022 (pre-intervention) and June-September 2023 (post-intervention). The training programme focused on:

• Optimising fresh gas flow rates
• Improving analgesia
• Promoting safe, effective low-flow anaesthesia

Low-flow anaesthesia, an established human medicine technique, reduces wastage of oxygen and volatile agents.

Results: Substantial Reductions Achieved

• Isoflurane usage decreased by 9.6%
• Oxygen usage down by 17.9%
• GHG emissions from anaesthetic gases reduced by 9.6%, from 14.6 to 13.2 tonnes CO₂e over four months

Statistical analysis confirmed that post-training cases had lower GHG emissions per anaesthetic, with key factors including oxygen usage, anaesthesia duration, and vaporiser settings.

A hypothetical model suggested that consistent use of low-flow anaesthesia could cut emissions by up to 34% compared to current practice.

A core principle of the project was patient safety. All hospitals used multiparameter monitoring, including inspired and expired oxygen, enabling safe FiO₂ levels throughout. The findings demonstrate that low-flow anaesthesia can be responsibly and effectively implemented in equine practice.

Luís Filipe Louro commented: “Our results highlight the enormous potential for veterinary teams to reduce anaesthetic gas emissions through structured training, regular equipment checks, and a shift towards evidence‑based low‑flow techniques. It shows we can become significantly more sustainable without compromising safety.

“By embedding sustainable anaesthesia practices across our equine referral network, CVS is demonstrating how veterinary groups can take meaningful action on climate responsibility. Our group now plans to extend this work further, supporting its equine hospitals to adopt low‑flow anaesthesia consistently, invest in efficient anaesthetic equipment and encourage wider profession‑wide engagement. I’m incredibly proud of the CVS Equine teams for embracing this work and demonstrating what is possible.”

CVS Group operates over 500 veterinary practices and referral centres in the UK and Australia, investing £122 million since 2023 in sites, equipment, and training to deliver the highest standards of animal care.