Minimizing desflurane use and decreasing fresh gas flows, Anesthetics

Project completed as part of the South Health Campus, Alberta Health Services Green Team Competition, 2024

Team members

• Vivian Ip, Nathan Brown, Alan Chu, Leyla Baghirzada, Joanna Fifen, Esther Ho, Ryan Endersby

Setting / patient group: Anesthesia department

Issue

Not all anesthetic volatile agents have the same environmental impact. Evidence from life cycle analysis has shown that desflurane is more carbon-intensive when compared to sevoflurane (2540 times for desflurane versus 130 times for sevoflurane the global warming potential (GWP) over 100 years. Furthermore, desflurane is less potent, which means more than 3 times as much agent mass is required to produce the same clinical effects. Recent literature also demonstrated occupational exposure poses a potential health hazard to healthcare personnel, with associated genetic damage and oxidative stress. (6-7) A recent quality improvement project showed a reduction of desflurane use has an associated usage cost reduction of 58%.

Intervention

To implement changes, an email was sent to all anesthesiologists at South Health Campus for feedback, identifying six desflurane users who were then individually approached. Initial resistance led to a stepwise approach, starting with a lecture on environmental sustainability, followed by stickers on anesthetic machines highlighting gas emissions. Desflurane vaporizers were relocated to increase inconvenience, and reminders to use low fresh gas flow and end-tidal control were placed on machines and charting computers. Data on desflurane and sevoflurane use, and anesthetic cases will be collected three months before and after the changes to assess impact.

Outcomes

Patient outcomes: Clinically, there is no risk to switch from desflurane to sevoflurane, or to use low fresh gas flow. In fact, there are more risks of adverse effects from using desflurane than sevoflurane. For instance, desflurane is an irritant and may cause bronchospasm, increase sympathetic response, increased cerebral blood flow and increase cerebral spinal fluid pressure which are deleterious in certain situations. As it has a reduced potency, an increased amount is necessary to produce the same clinical response compared to sevoflurane.

There is a small potential perceived benefit of earlier wake-up from desflurane compared to sevoflurane, however the undesirable effects outweigh the purported benefit of earlier recovery. With better understanding of the pharmacokinetic properties of sevoflurane, anesthesiologists can learn to adjust the dosage of sevoflurane towards the end of surgery, and equalize the recovery times between desflurane and sevoflurane.

Environmental and Economic sustainability:

Following our changes, when taking into account of the increased case volume in 2024, we have

seen a 17% reduction in desflurane usage and a 6% increase in sevoflurane usage when compared to the average monthly usage in 2023. This is a saving of 12 Tonnes CO2e, equivalent to driving 46,332 km in an average car.

Unexpectedly, the use of sevoflurane was initially showing as a cost increase. The team will continue to collect data over the coming 6 months to offer a better reflection of the financial (and carbon) impacts of this project. This unexpected outcome has been flagged with our Surgery Strategic Clinical Network (SCN) who plan to further review the findings.

Social sustainability:

Two staff raised concerns about moving desflurane to the supply room, due to impacts on professional autonomy. A stepwise approach was adopted to help them gradually adjust and understand the benefits of low fresh gas flow, end-tidal control, and the adverse effects of desflurane. Differences in pharmacokinetics between desflurane and sevoflurane were noted, as well as updated CAS guidelines and the push for environmentally sustainable anesthesia in other Canadian provinces, highlighting the broader health benefits of these changes.

Key learning point

This project has been extremely helpful in team bonding, educating other anesthetists, and realizing the importance of social aspects for implementing changes. The key elements that contribute to the successes and learning in this project is the need to assess the emotion of the department or team about changes, then implement changes in a stepwise approach after discussion.