Environmental Effect of Fluorinated Gases in Vitreoretinal Surgery: A Multicenter Study of 4,877 Patients

Abstract

To investigate the direct contribution to carbon emissions of fluorinated gases used in all vitreoretinal (VR) procedures utilizing gas tamponade and assess the respective carbon footprint of the three different gas delivery systems. A multicenter, retrospective, environmental impact study. All VR procedures using fluorinated gases between 2017 to 2020 at the Manchester Royal Eye Hospital (MREH) and Birmingham and Midland Eye Centre (BMEC) (the second and third largest VR centers in the UK), and between 2019 to 2020 at the University Hospitals Coventry and Warwickshire (UHCW) were included. CO2 equivalent mass (CO2EM) was calculated from the mass of each gas used, according to the Intergovernmental Panel on Climate Change. A total of 4877 (1883 SF6 [38.6%], 2096 C2F6 [43.0%], and 897 C3F8 [18.4%]) procedures were analyzed. UHCW and BMEC utilized single-use 30 mL and 75 mL cannisters, respectively. MREH used four cylinders of each gas over 4 years (2 kg SF6, 1 kg C2F6, 1 kg C3F8). Mean CO2EM per patient was: MREH 111.8 kg, BMEC 7.5 kg, and UHCW 2.7 kg. For MREH and BMEC, the CO2EM was 73.4 metric tons annually (if all cases were performed with i) 30 mL: 3.7 tons and ii) cylinders: 148.0 tons, x 40-fold difference), equating to 599,400 (30,500-1.2 million) km travelled by a passenger car. The current use of SF6 in VR surgery accountsfor 0.11% of total SF6 use; if 30 mL cylinders were exclusively used in the UK, this could be lowered to 0.01%. This study highlights the significant waste associated with large gas cylinders and demonstrated that 30 mL cannisters can lead to a marked reduction in carbon emissions, even after accounting for the increased carbon footprint involved in their manufacture and disposal.