Estimation of carbon emissions associated with tibial plateau levelling osteotomies in 10 dogs

Objective: To describe a method of estimating the carbon emissions resulting from 10 clinical canine surgical procedures.

Study design: Prospective observational cohort study.

Animals: A total of 10 adult client-owned dogs presenting to two private referral centres in the UK for tibial plateau levelling osteotomy (TPLO) using either isoflurane or sevoflurane for maintenance of anaesthesia.

Methods: Single-use consumables, pharmaceuticals and waste streams were recorded. Volatile anaesthetic use was calculated based on fresh gas flow (FGF) and vaporizer setting. Travel of owners and staff involved in the procedure was recorded (the latter adjusted by procedure length relative to working day). Energy use was calculated based on the clinics monthly usage adjusted for floor area of rooms used. Overnight hospitalisation, kennelling consumables and a revisit for postoperative radiography were excluded. Carbon accounting was performed using published carbon conversion factors ('bottom-up analysis') if available, or conversion factors based on cost ('top-down'). Data are presented as median (range) and totals per emission category.

Results: Carbon emissions from all cases amounted to 667.2 kgCO₂e. In these two clinics, median carbon emissions from a canine TPLO were 63.5 (47.6-93) kgCO₂e, which is equivalent to driving 372 km (231 miles) in an average UK passenger car. Travel accounted for 30.1% of carbon emissions. Volatile anaesthetics accounted for 21.4% of carbon emissions, with other pharmaceuticals accounting for 24.0%. Consumables, building energy and waste disposal accounted for 19.7%, 3.9% and 0.9% of carbon emissions, respectively.

Conclusions and clinical relevance: Likely carbon hotspots for canine orthopaedic procedures include travel and pharmaceuticals, particularly volatile anaesthetic agents. Carbon reductions should focus on reducing travel emissions, streamlining pharmaceutical use and lower-carbon anaesthetic techniques. Future research should focus on improving carbon accounting methodology and widening the range of cases assessed.