If you’ve ever wondered how people stay unconscious during a surgical procedure, you’re not alone. There are two main ways to keep someone unconscious, either a medication that is given intravenously or by using halogenated gases. The halogenated gases are used often because they are so easy to administer. That’s why some refer to an anesthesiologist as “Gas Doctor”! There are different types of halogenated gases. The two most common agents used in Canada are: Sevoflurane and Desflurane.

Unfortunately, these gases have some negative environmental consequences. If these gases are vented out of the hospital into the atmosphere as-is, they act as a greenhouse gas. As we know, greenhouse gases contribute to global warming (a.k.a Climate Change or the Climate Crisis) over a specific period of time. In Toronto, approximately 75,000 general anesthetics are provided every year across six fully affiliated academic hospitals. This represents a significant proportion of anesthesia services in Canada. So, it makes sense for us to try to give environmentally friendly anesthetics. Luckily, we can do that without compromising patient care.

Figure 1. shows the global warming impact of three different halogenated gases. Desflurane has the highest carbon foot print between all of the other gases.

What does that mean? Well, it means that the carbon footprint from using Desflurane for 7 hours on minimum flow, emits CO2 equivalent of driving 2554 KM by car, more than the distance from Toronto to Winnipeg.

It also means that the carbon footprint from using Sevoflurane for 7 hours on minimum flow produces the CO2 equivalent of driving 145 KM by car, like driving from Toronto to Collingwood.

1 dose of Desflurane is as damaging to the environment as about 18 doses of Sevoflurane.

Like driving from Toronto to Winnipeg vs driving to Collingwood.

Sadly, despite these facts, Desflurane is still commonly used agent among Gas Doctors. To prove that, we compared the ratio of Desflurane use to other volatile anesthetics used in the operating room among Toronto area academic hospitals between 2018 and 2019. And here is a quick visual for the results.

Many Anesthesiologists may not be aware of the climate impact, or may choose Desflurane out of habit or convenience.

What can you do to help discourage the use of Desflurane at your institute?

Easy, we recommend taking the following steps:

  1. Remove Desflurane from the OR, and store it out of reach (e.g. the sterile core)
  2. Frequently remind staff and trainees of the environmental impact of Desflurane
  3. Set a goal at your site to decrease usage by 50%
  4. Perform an annual review of Desflurane purchases to track progress in reducing Desflurane use
  5. Remind staff to use low flows with any anesthetic gas
  6. Form a sustainability committee to follow up annually

About the Authors: Huda Khayyat is a PGY-5 resident and Safia Nazarali is a PGY-3 resident  in the Department of Anesthesia at the University of Toronto.