The study by Forbes McGain et al. compares the carbon dioxide equivalent emissions associated with different anesthesia modalities—general, spinal, and combined (general and spinal)—used during total knee replacement surgeries in Melbourne, Australia. Utilizing a prospective life cycle assessment for 29 patients, the study analyzes the environmental impact of these anesthetic methods with a detailed breakdown of their carbon contributions.

Key Findings:

• Emission Levels: The emissions for general, spinal, and combined anesthesia were closely similar, demonstrating that no single method consistently produced lower emissions. The primary sources of emissions varied with each method, including electricity for patient warming, single-use items, and specific anesthetics like sevoflurane.
• Major Emission Contributors: For general and combined anesthesia, sevoflurane was a significant contributor. In spinal and combined cases, the washing and sterilizing of reusable items accounted for a notable share of emissions. Oxygen use also played a crucial role in the carbon footprint of spinal anesthesia.
• International Comparison: The study modeled the carbon emissions in different international contexts, showing variability based on local electricity grids’ carbon intensity.

Recommendations:

• Utilizing low-flow anesthesia or total intravenous anesthesia could reduce emissions.
• Reducing the use of single-use plastics and optimizing oxygen flows could decrease the carbon footprint.
• Collaboration with engineers to improve energy efficiency and integrate renewable energy sources is suggested to mitigate the broader environmental impact.