Reducing the Carbon Footprint of Operating Rooms Through Education on the Effects of Inhalation Anesthetics on Global Warming

Environmental issues are a global concern and a problem that everyone must solve together. Recently, there have been efforts to reduce carbon footprint in the medical field. In the field of anesthesiology, as it became known that inhalation anesthetics have a significant impact on global warming, the European Union officially declared in 2022 to ban the use of the inhalation anesthetic desflurane from 2026. Additionally, the World Federation of Societies of Anesthesiologists (WFSA) published guidelines on the use of inhalation anesthetics to reduce air pollution in 2022.

Inhalation anesthetics are known to account for 0.01-0.1% of the total carbon dioxide equivalent (CO2e) contribution to global warming. This is 5% of hospital CO2e and 50% of surgery-related CO2e. Only 5% of the inhalation anesthetic is metabolized in the patient's body, and the remaining 95% is discharged through the anesthetic gas scavenging system of the anesthesia machine and released into the atmosphere without any additional post-processing. Representative inhalation anesthetics that are currently widely used include nitrous oxide (N2O), sevoflurane, desflurane, and isoflurane. Comparing their global warming potential (global warming potential 100, GWP100; which indicates the degree of greenhouse gas effect compared to CO2 over 100 years), nitrous oxide 298, sevoflurane 130, desflurane 2540, and isoflurane 510. Among these, desflurane shows the highest GWP100 and is presumed to be due to its high minimum alveolar concentration. In addition, nitrous oxide and isoflurane have relatively low global warming potential, but they can destroy ozone and, in particular, nitrous oxide has a half-life of 114 years, so it can stay in the atmosphere for a long time and affect global warming.

Several studies have reported significant reductions in CO2e and medical costs along with a reduction in the use of these two anesthetics after educating anesthesia staff on the use of desflurane and nitrous oxide. In one study, desflurane usage was reduced by 95.63% and CO2e was reduced by 87.88%. In another study, desflurane use was reduced from 8.3% to 0.3%, CO2e was reduced from 1,681 to 10, and medical costs were saved by $200,000 over 3 years. In Korea, sevoflurane and desflurane are the most used, but the impact of inhalation anesthetics on global warming is not well-known to clinicians, and there are no related studies.

After educating anesthesiologists about the impact of inhalation anesthetics on global warming, the investigators analyzed the use of inhalation anesthetics and changes in CO2e before and after education in actual clinical situations to determine whether education alone could reduce their use. In addition, the investigators aim to show that this can have a positive impact on global warming and economic losses.

Education on the effects of inhalation anesthetics on global warming was conducted for every anesthesiologist in our hospital, and only medical records were reviewed retrospectively to confirm if there were any changes in choice of inhalation anesthetic, and fresh gas flow before and after receiving the training. Inevitably, patients for whom general anesthesia was performed by untrained anesthesiologists about the effects of inhalation anesthetics on global warming were excluded from the analysis. This is an observational study because there is no intervention applied to the patient, and patients not included in the study are also administered general anesthesia using the same method.