Less inhaled anesthetics, less greenhouse gas emissions
Volatile anesthetic agents are powerful greenhouse gases released into the atmosphere during every procedure. Reducing their use is therefore an urgent ecological priority. One increasingly popular and innovative strategy is the recycling of anesthetic gases. But why does it still make sense to prioritize reduction over recycling – and how can this be achieved safely and effectively using low-flow anesthesia?
Time to act
Volatile anesthetics are responsible for up to 35% of a hospital’s greenhouse gas emissions[1], making them a significant environmental concern. While the average German emits about 11 tons of CO₂ per year, anesthesiologists reach occupational emission levels of up to 17.1 tons per person annually[2]. For example, during a 7-hour procedure with a fresh gas flow of 2 liters per minute, the use of highly polluting agents like desflurane or nitrous oxide can result in a carbon footprint equivalent to driving from Norway to South Africa[3][4].
In addition, volatile anesthetics pose occupational health risks for OR staff exposed to escaping gases. This leakage also requires constant adjustment of gas delivery, leading to increased consumption and added costs. It’s clearly time for hospitals and anesthesiologists to take action.
Recycling anesthetic gases: Turning waste into value
Traditionally, anesthetic gases are scavenged at the anesthesia machine and vented directly into the atmosphere. However, new capture systems offer a promising alternative. In these setups, exhaled gases are filtered, collected, and prepared for reuse using activated charcoal filters connected to the anesthesia device.
However, questions remain about how much of the delivered anesthetic gas is actually captured perioperatively and can be recycled[5][6]. A 2022 study found that only 25% of desflurane was captured by the charcoal filter – with most of the gas still escaping into the atmosphere. The authors suggest that at the time of extubation, patients may still retain significant amounts of anesthetic agents, which are then exhaled into the room air[7].
Recycling is therefore a promising measure to reduce hospital greenhouse gas emissions – but further research is needed to assess its effectiveness[8].
Reduce first, then recycle
The European Society of Anesthesiology and Intensive Care (ESAIC), The German Society of Anesthesiology and Intensive Care Medicine (DGAI) and the Professional Association of German Anesthetists (BDA) offer specific recommendations for sustainable anesthesia [9]. These include:
- Avoiding desflurane as much as possible
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Preferring sevoflurane due to its lower global warming potential
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Choosing total intravenous anesthesia (TIVA) or regional anesthesia
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Consistently applying minimal-flow anesthesia to reduce anesthetic agent use[10].
A two-step strategy – reducing the use of volatile agents first, then recycling what is still used – makes sense for several reasons:
- Lower gas use leads directly to cost savings by reducing procurement needs
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What isn’t consumed doesn’t need to be recycled
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Less gas consumption means less exposure and emissions
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Even if recycling proves only partially effective, less residual gas escapes into the atmosphere
Automated low-flow anesthesia: Less anesthetic gas, fewer emissions
Low-flow anesthesia, supported by Automatic Gas Control (AGC) to regulate oxygen delivery, has the power to safely reduce anesthetic agent consumption by up to 58%[11][12].
Two hospitals in Belfast, UK, recently reduced their volatile agent use by 30.5%[13] and 42%, respectively, achieving significant cost savings. Belfast City Hospital projected annual savings of €30,394 across seven anesthesia workstations, with a return on investment for the software upgrade in under a year. (Read the full case study)
At Imelda Hospital in Bonheiden, Belgium, the anesthesiology department cut its ecological footprint by over 1,600,000 kg of CO₂ equivalents. “The average footprint per person in the Western world is about 10,000 kg annually. Our adjusted practices enable us to reduce the equivalent of more than 160 people,” said Dr. Guy Schols, Head of Anesthesia.
Power feature: Automatic Gas Control (AGC)
Automatic Gas Control (AGC) is a software feature that regulates fresh gas and anesthetic concentration to reach target values for inspired oxygen (FIO₂) and end-tidal agent concentration (EtAA). Once these targets are met, AGC automatically reduces the fresh gas and anesthetic delivery to a minimum. A speed and prediction tool provides insight into the expected course of anesthesia, enabling safe and effective low-flow application.
Dr. Jan Hendrickx, anesthesiologist at OLV Hospital in Aalst, Belgium, explains:
“Instead of manually adjusting fresh gas flow and vaporizer settings to maintain target concentrations, a workstation equipped with AGC does this automatically. This allows clinicians to minimize fresh gas flow and anesthetic gas waste.”
Our conclusion
Prioritizing anesthetic gas reduction over recycling is a strategic decision that enables both cost savings and a measurable reduction in a hospital’s carbon footprint. With low-flow anesthesia and automated gas control, this approach is not only feasible but safe. Clinicians can reduce gas use, cut greenhouse gas emissions, and lower costs – without compromising care.