An Audit of Physical Waste and Fluoroscopy Energy Consumption in Vascular Surgery and Suggestions for the Future.

Abstract

Objectives: Hospitals are responsible for 4-5% of global greenhouse gas production and are significant contributors to climate change. We sought to understand the contributions of vascular surgery to the carbon footprint of hospitals by examining emissions from fluoroscopy and physical waste across common vascular surgeries.

Methods: Vascular operations at a single tertiary hospital were prospectively audited for physical waste. Additional cases from the same hospital were audited retrospectively for energy expenditure during fluoroscopy digital subtraction angiography (DSA). The fluoroscopy time (min), number of DSA runs, amplitude, and voltage were recorded, and subsequently, power (kW) and energy (kWh) were calculated. The operations were separated into cohorts based on operation: endovascular aneurysm repair (EVAR), thoracic endovascular aortic repair (TEVAR), transcarotid artery revascularization (TCAR), carotid endarterectomy (CEA), femoral endarterectomy with iliac intervention (Fem/Iliac), lower extremity bypass, endovascular lower extremity revascularization (Endo CLTI). Using a certified Greenhouse Gas Equivalencies Calculator from the US Environmental Protection Agency, total carbon dioxide emissions (CO₂e) were estimated.

Results: 18 vascular operations were audited for physical waste. Lower extremity bypasses produced the largest amount of CO2e from physical waste (85.75 kg CO2e, 95% CI 71.4-100.2), while the least was produced by CEA (57.22 kg CO2e, 95% CI 48.7-65.7). No significant correlation was seen between operative length and amount of waste. 97 operations were retrospectively audited for fluoroscopy energy use during DSA runs. EVAR produced the largest CO2e from DSA runs (41.11 kg, 95% CI 28.82-53.40), while the least was produced by TCAR (7.33 kg, 95% CI 5.15-9.49). When DSA CO2e were analyzed against fluoroscopy time, TEVAR produced CO2e at the highest rate of 3.63 kg/min DSA, while TCAR produced CO2e at the lowest rate of 1.37 kg/min DSA. Although no linear correlation was found between operation length and CO2e from waste (r2= 0.099), a linear correlation was found between fluoroscopy time and CO2e (r² = 0.76).

Conclusions: Vascular operations, on average, generate 108.47 kg of CO2 emissions from waste and fluoroscopy, the equivalent of driving an average gasoline-powered vehicle for 278 miles. This study found a correlation between increased fluoroscopy time and CO2 emissions. It also found that the rate of emissions differs between different operations, suggesting a role in optimizing fluoroscopy and intraoperative techniques to lower emissions. Efforts to track current energy output from imaging devices, investing in efficient devices, and adjusting intraoperative settings may all play a role in decreasing vascular surgery's environmental footprint.