A review of the environmental impacts of desflurane and nitrous oxide

By Yannick De Silva

What is the problem?

 Much of the media reports carbon dioxide (CO2) emissions but fails to address the impact that volatile inhaled anaesthetic gases have on the environment. Desflurane, in particular, is thousands of times more potent than CO2 and is a significant contributor to greenhouse gas emissions (1). The effects of these emissions ultimately cause higher temperatures for current and future generations. Nitrous oxide (N2O), a gas that may be combined with volatile gases, contributes to the destruction of the ozone layer (2). This permits more ultraviolet radiation to the earth, making us more susceptible to skin damage and melanoma. Interestingly, more than 95% of the anaesthetic gases used during surgery are exhaled and indirectly vented into the atmosphere (3). This may be following release from a hospital’s anaesthetic gas scavenging system, via leaks in anaesthetic machine valves and manifolds, or through the venting of part-full N2O gas cylinders once returned to the supplier (4). When used as a combination, desflurane and N2O have significantly higher global warming potential (GWP) compared to other flurane-N2O combinations (5). We can liken the CO2 emissions of these volatile gases to the equivalent emissions from driving for one MAC-hour, with N2O and desflurane producing CO2 emissions equating to 95 km and 320 km of driving respectively (6). Furthermore, while desflurane exerts most of its environmental effect over the initial 20 years after use, N2O has longer-lasting impacts that can span over 100 years following its use (5). This poses obvious threats to our current and future generations.

What are the solutions?

When considering pragmatic solutions, it is important for anaesthetists to make shared decisions with the patient in the pre-operative period, without compromising the quality of care of the patient. Suggested clinical practice responses include:

  • Recycle unmetabolised exhaled gas using a closed “circle system” (5)
  • Avoid routine use of desflurane and N2O, e.g. move desflurane vapourisers away (7)
  • Consider total intravenous anaesthesia (TIVA) or regional anaesthesia instead (8)
  • If gases are used, reduce fresh gas flow especially during maintenance phase (9)

Anaesthesia providers have a duty and responsibility to advocate for systems change in their workplace and the broader medical community (5). Through a collaborative approach with colleagues, gas suppliers, hospital quality improvement teams, and sustainability officers, anaesthetists can promote environmentally sustainable behaviours (10). Suggested systemic solutions for anaesthetic providers include:

  • Foster a perioperative culture that values sustainability (11)
  • Contribute to life cycle assessments for anaesthetic drugs (12)
  • Lead sustainability audits within their hospitals
  • Advocate for infrastructure development in hospitals
  • Recommend suitable redesign for proposed renovation of operating theatres
  • Design and follow a ‘5R’ approach to minimising anaesthetic waste – reducing, reusing, recycling, rethinking and researching (13)
  • Strengthen environmental sustainability principles in continuous professional development courses

Where to from here?

The environmental impacts of desflurane and N2O, commonly used inhalation anaesthetic agents used during surgery, cannot be underestimated. Specifically, desflurane contributes to greenhouse gas emissions and increases surface temperatures on our planet Earth. N2O on the other hand, causes destruction of the ozone layer and makes us susceptible to skin damage and melanoma. Anaesthetists can undertake pragmatic clinical practice solutions to make meaningful systems changes. Ultimately, it is the responsibility of our healthcare providers to seed environmentally conscious behaviours amongst their colleagues, communities and networks. It would be interesting to survey whether the environmental impacts of anaesthetic gases feature in the preoperative discussion between anaesthetist and patient. It would also be worthwhile to explore whether other causes of perioperative environmental waste, such as single-use syringes and laryngoscopes, form part of this conversation.


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