Sustainable anesthesia: Charité lowers CO2 emissions in the OR by 80 percent

Charité – Universitätsmedizin Berlin has reduced the annual CO₂ emissions originating from gases used for anesthesia by over 80 percent since 2018. This reduction in carbon emissions was achieved by using climate-friendlier anesthetics in the operating room. As a study published in the journal Anesthesia & Analgesia* demonstrates, education and, in particular, fundamental decisions were the keys to success.

Gaseous anesthetics have a climate impact in that they heat the atmosphere much like carbon dioxide (CO₂). However, their effect is much stronger: A single kilogram of desflurane, for example, contributes almost 8,000 times as much to the greenhouse effect over a five-year period as the same amount of CO₂. The emissions from a seven-hour operation in which desflurane is used as an anesthetic are equivalent to those from driving a car almost 7,850 kilometers. That’s about the distance from Berlin to Ulaanbaatar, Mongolia. This makes desflurane by far the worst offender among anesthetic gases in terms of climate impact.

Action starting in 2018

“Most anesthesiologists don’t know about the climate impact of inhaled anesthetics because it isn’t part of their standard training,” explains Dr. Susanne Koch, a lecturer and anesthesiologist at Charité and the leader of the study. A member of the European Society of Anaesthesiology and Intensive Care (ESAIC) Sustainability Committee, Koch is committed to improving sustainability in anesthesiology, including at Charité. “To change that, we introduced regular informational events and continuing and professional education activities in 2018.”

The heads of the anesthesiology departments also revised the guidelines for administering anesthesia, and desflurane was eliminated Charité-wide as of late 2023. Instead, the departments are increasingly relying on local anesthesia and using propofol, an anesthetic that is given intravenously, so it has much less impact on the climate than inhaled anesthetics. For cases where anesthetic gases are necessary for medical reasons, sevoflurane is used in what is known as the “minimal flow” method, meaning there is little flow of gas. Sevoflurane’s greenhouse gas impact is less than a third of that of desflurane.

Lower emissions, lower costs, no drawbacks for patients

“These actions have allowed Charité to reduce anesthesia-related carbon emissions from over 7,500 metric tons per year before 2018 to 1,454 in 2023. That’s more than 80 percent,” says Astrid Lurati, Chief Financial and Infrastructure Officer of Charité. “This works out to savings of about 6,000 metric tons of carbon dioxide a year, about the same as the emissions from 300 households in Germany. And because desflurane is also one of the most expensive inhaled anesthetics, our annual costs for anesthetic agents also fell by nearly half between 2015 and 2023.”

There are no medical drawbacks associated with the switch for patients – quite the opposite. “Patients wake up calmer after anesthesia with propofol, and nausea is less common,” Koch notes. “Desflurane makes it possible to control the duration and depth of anesthesia very effectively, which is why anesthesiologists like to use it. But highly effective anesthetic control is also possible when propofol is used, thanks to EEG-based monitoring, which is when brain activity is used for guidance.”

The biggest impact: management decisions

In their study, Koch and her team of researchers investigated which measures have the biggest impact on CO₂ emissions from anesthetics. They found that publications, continuing and professional education activities, and informational events – both internally within Charité and at specialized conferences – brought continuous reductions in emissions. “But the fastest and most lasting effect came from adjustments in the centralized, standard rules that all anesthesiologists are required to follow in their work,” Koch says. “This shows how important these kinds of fundamental decisions supported by the management level are.”

 

*Schwiethal A et al. The Power of Education to Reduce the Carbon Footprint of Volatile Anesthetics in Clinical Practice. Anesth Analg. 2025 Feb 25. doi: 10.1213/ANE.0000000000007375

 

Calculation of CO₂ emissions
For better comparability of climate-active substances, their warming impact on the atmosphere is expressed over a specific period as what is known as global warming potential (GWP) in CO₂ equivalents. GWP is typically given for a period of 100 years (GWP100). However, because anesthetic gases remain in the atmosphere for a relatively short time (14 years for desflurane, 1.1 for sevoflurane), the largest portion of their global warming impact takes place within just a few years. With that in mind, the CO₂ equivalents indicated in the text above are based on GWP5, meaning global warming potential over five years. Taking the GWP100 value as a basis instead, emissions from inhaled anesthetics at Charité amounted to more than 1,500 metric tons of CO₂ equivalents prior to 2018. That figure was reduced to 142 metric tons by 2023.

Sustainability at Charité
Charité is guided by the 17 United Nations Sustainable Development Goals (SDGs) and pursues them across four strategic fields: environment, social matters, health, and governance. To do this, it employs a large number of measures, such as long-lasting construction concepts, resource conservation, sustainable mobility, and energy upgrades for technical equipment and facilities. For example, Charité has replaced some 60,000 conventional lamps with LEDs, introduced a no-deposit reuse system in all food service establishments, and switched healthcare staff’s uniforms to products made from Tencel with “Grüner Knopf” (Green Button) sustainability certification. This has allowed Charité to lower its CO₂ emissions from 126,600 metric tons in 2016 to 104,320 in 2023.

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