Carbon Footprint Analysis Of Different Anaesthetic Techniques For Cataract Surgery: Implications For Sustainable Healthcare Practices

Healthcare is a substantial contributor to global carbon emissions, with operating theatres being particularly resource intensive environments. Cataract surgery is one of the most frequently performed surgical procedures worldwide. This study aimed to estimate the carbon footprint, measured in carbon dioxide equivalents (CO₂e), of various anaesthetic techniques routinely employed in cataract surgeries and develop recommendations to reduce environmental impact without compromising high standards of clinical care.

Department of Ophthalmology, Maidstone and Tunbridge Wells NHS Trust, Maidstone, Kent, United Kingdom

We employed a 'top-down' or spend-based approach to calculate CO₂e. Detailed inventories of typically used consumables and pharmaceuticals for each anaesthetic technique: sedation, regional (sub-tenon’s) block, general anaesthesia (GA) with endotracheal tube (ETT)/laryngeal mask airway (LMA), total intravenous anaesthesia (TIVA) or volatile were compiled. Data were gathered during a one-week period (between 20th to 26th August 2024) and projected to provide estimates over a one-year period. Each item’s cost of acquisition was calculated based on the previous year’s spend and multiplied by greenhouse gas emission factors from databases such as Greener NHS. Comparative analyses of the carbon footprint of each technique were performed.

Sedation demonstrated the lowest carbon footprint at 3.09kg CO₂e per case, equivalent to driving 10 miles in a petrol car. Sub-tenon's block produced 25.66kg CO₂e, bringing the total for sedation with block to 28.75kg CO₂e. General anaesthesia techniques had substantially higher carbon footprints, varying by airway device (ETT: 36.90kg CO₂e, equivalent to 190 miles; LMA: 28.41kg CO₂e, 78 miles) and maintenance method (volatile-based: 16.88kg CO₂e, 75 miles; TIVA: 18.30kg CO₂e, 80 miles). Emergency drugs, kept on standby for all anaesthetic lists, contributed 12.12kg CO₂e. Across all techniques, disposable equipment generated a greater proportion of emissions than pharmaceuticals.

Our analysis revealed significant differences in carbon footprint between anaesthetic techniques for cataract surgery. Where clinically appropriate, sedation with block/topical anaesthesia is preferable from a sustainability perspective. Minimal differences between volatile-based and TIVA techniques may be due to procedure duration and spend-based methodology. Substantial emissions reductions could be achieved by implementing pre-filled syringes for emergency drugs and reducing unused single-use consumables in sub-tenon's packs. These findings provide an evidence base for developing more environmentally sustainable anaesthetic practices for high-volume cataract surgery