Environmental effect of fluorinated gases in vitreoretinal surgery: a multicenter study of 4,877 patients.

PURPOSE To investigate the direct contribution to carbon emissions of fluorinated gases used in all vitreoretinal (VR) procedures utilising gas tamponade and assess the respective carbon footprint of the three different gas delivery systems. DESIGN A multicenter, retrospective, environmental impact study METHODS: All VR procedures using fluorinated gases between 2017-2020 at the Manchester Royal Eye Hospital (MREH) and Birmingham and Midland Eye Centre (BMEC) (the second and third largest VR centres in the UK), and between 2019-2020 at the University Hospitals Coventry and Warwickshire (UHCW) were included. CO2 equivalent mass (CO2EM) was calculated from mass of each gas used according to the Intergovernmental Panel on Climate Change. RESULTS A total of 4,877 (1,883 SF6[38.6%], 2,096 C2F6[43.0%], 897 C3F8[18.4%]) procedures were analysed. UHCW and BMEC utilise single use 30ml and 75ml canisters, respectively. MREH used four cylinders of each gas over four years (2kg SF6, 1kg C2F6, 1kg C3F8). Mean CO2EM per patient was MREH:111.8kg, BMEC:7.5kg for BMEC and UHCW:2.7kg. For MREH and BMEC, the CO2EM was 73.4 metric tonnes annually (if all cases performed with i)30ml:3.7tonnes and ii)cylinders:148.0 tonnes, x40 fold difference); equating to 599.4thousand (30.5thousand-1.2 million)km travelled by a passenger car. Current use of SF6 in VR surgery accounts for 0.11% of total SF6 use; if 30ml cylinders were exclusively used in the UK, this could be lowered to 0.01%. CONCLUSIONS We highlight the significant waste associated with large gas cylinders and demonstrate that 30 ml canisters can lead to a marked reduction in carbon emissions, even after accounting for the increased carbon footprint involved in their manufacture and disposal.