A Major Source Of Greenhouse Gases In Hospitals? Anesthesia

ANNA ROTHSCHILD: This is Science Friday. I’m Anna Rothschild.

IRA FLATOW: And I’m Ira Flatow.

ANNA ROTHSCHILD: And it’s climate week in our home base New York City, where climate champions are gathering to talk about solutions.

[MUSIC PLAYING]

SPEAKER 1: I’m excited about being inspired. Climate week is a space where I come to really focus on solutions rather than problems, and that the better we look after one another, the better off we’ll all be.

Forests are near and dear to my heart, but I also get super jazzed about like ocean fresh water-based solutions too, like kelp forests. I’m a terrestrial girl, but I love me some aquatic stuff, too.

I think that when folks lead in their own community and are fighting for more resources both in their community and across the city to address climate justice issues, it’s really inspiring.

ANNA ROTHSCHILD: Did you know that some of the gases used in anesthesia are really strong greenhouse gases? A few years ago, Seattle Children’s Hospital analyzed its carbon footprint and found that the gases used in anesthesia made up about 7% of the whole hospital’s total emissions right behind emissions from heating and power and those from commuting. Faced with this problem, pediatric anesthesiologist Dr. Elizabeth Hansen took matters into her own hands and slashed the operating rooms’ emissions. Dr. Hansen, welcome to Science Friday.

ELIZABETH HANSEN: Thank you so much. I’m so delighted to be here with you.

ANNA ROTHSCHILD: Well, I am delighted to be speaking with you. So what was your reaction when you learned that 7% of your hospital’s emissions were from the gases you use every day?

ELIZABETH HANSEN: Well, as an environmentalist and someone who had been spending sleepless nights worrying about the climate crisis and the future of planetary health, I was pretty shocked and upset to hear that the medications and gases that I used to take care of my patients every day were contributing to the problem.

ANNA ROTHSCHILD: Why does anesthesia have such a large carbon footprint?

ELIZABETH HANSEN: Well, a lot of the medications that we use are inhaled anesthetics including ones you may have heard of like nitrous oxide or laughing gas but also volatile anesthetics like sevoflurane and desflurane. And all of these gases are potent greenhouse gases as you mentioned.

So we compare greenhouse gases using a metric called global warming potential 100, which is the ability of a gas to warm the planet over a 100-year time horizon. And the anesthesia gases that we use range in their global warming potentials from about 300 for nitrous oxide up to 2,540 for desflurane.

ANNA ROTHSCHILD: Wow, that’s huge.

ELIZABETH HANSEN: Absolutely. The good news is there are lots of evidence-based practices that we can implement to reduce the impact of our inhaled anesthetics including avoiding use of these really high impact agents like nitrous oxide and does fluorine in favor of lower impact agents like sevoflurane or even using IV anesthesia medications that have a much, much lower impact.

ANNA ROTHSCHILD: Yeah, talk a little bit more about that. Can you tell us about all of the changes that you started making to really lower your carbon footprint?

ELIZABETH HANSEN: Yeah. So there are some really excellent evidence-based recommendations coming from the leaders in this field and the ASA including using lower-impact agents like sevoflurane, avoiding use of nitrous oxide and desflurane, those higher-impact agents, using low fresh gas flows, which allows us to be more efficient with our use of anesthesia gases so that we waste less of them while still delivering an adequate amount to our patients, and using IV alternatives when clinically appropriate.

ANNA ROTHSCHILD: So first you opted to use anesthetics that are less greenhouse gassy, and sometimes you use IV anesthesia instead of gas. And when you do use gas, you are now administering it more efficiently so that you waste less. But I guess I’m wondering why that administration was so inefficient in the first place.

ELIZABETH HANSEN: Yeah. So a couple of reasons. One is that in pediatric anesthesia, we often have kids breathe anesthesia gases to go off to sleep with a mask, and we used to use really high fresh gas flows for that. We realized that we didn’t need to use high fresh gas flows and that there was really no difference when we lowered our fresh gas flows in terms of the experience of the patient and how quickly they fell asleep. So we were able to reduce our fresh gas flows and save a lot of anesthesia gases that way.

The other reason is something we discovered along with others around the world who’ve discovered the same thing that the method that we use to deliver nitrous oxide to our operating rooms through a centrally piped system is notoriously leaky. So because of the design and the way that we deliver nitrous oxide throughout the hospital, we were actually wasting about 90% of the nitrous oxide that we purchased before it even got to patients for use.

ANNA ROTHSCHILD: Wow. How did you make these changes while also making sure your patients were safe?

ELIZABETH HANSEN: So we made a lot of changes as a group. I have to give a lot of credit to our leadership at Seattle Children’s Hospital at the hospital level and in my department of pediatric anesthesia as well as every single person in my anesthesia group who really took what I had to say to heart. So we implemented the evidence-based practices that I talked about.

And then we also used a system to track our emissions, not just the annual purchasing data, which is how we learned about 7% of our total hospital emissions coming from anesthesia gases but individually tracking so that we could all see– every single person in our department could see the carbon footprint or carbon equivalent footprint of our anesthesia delivery for all of the cases that we gave anesthesia to in the operating rooms. And so allowing folks to see the impact of their choices really drove behavior changes.

So, for example, I would send out a report every month to our entire group outlining the recommendations about changes that we should make to our anesthesia delivery, stories from the lowest emitters in the group so that they could share the techniques that they had been honing and perfecting, and celebrating the successes that we had that allowed us to make a tenfold reduction in our carbon emissions from anesthesia gases in the operating rooms.

ANNA ROTHSCHILD: That’s amazing.

ELIZABETH HANSEN: Thank you. I’m really proud of our group and really impressed with everyone’s dedication to this project.

ANNA ROTHSCHILD: When we talk about climate solutions, the medical field gets left out a lot of the time. What are some other solutions in medicine that you’re excited about?

ELIZABETH HANSEN: You said this exactly right. The health care community as a whole gets a pass for our carbon footprint, but we shouldn’t. Global health care is responsible for about 4.5% of global emissions. So there are a lot of things that we can do, and many of them are things that other industries are doing so decarbonizing our energy and our buildings and working with folks who design greener buildings to make our health care facilities more green.

Others are medication swaps. So I learned that metered dose inhalers for medications like albuterol can have propellants in them that are really potent greenhouse gases, but there are dry powder inhaler alternatives that have a much lower carbon footprint. So that’s another area of an easy medication swap that can have a big impact.

ANNA ROTHSCHILD: What’s your proudest moment from this whole process?

ELIZABETH HANSEN: Well, I have a couple of things to say for that. So one is what we’ve achieved at Seattle Children’s Hospital hasn’t stopped in Seattle. I had colleagues around the world in pediatric anesthesia who wanted to do the same thing, and so we joined together to create a consortium called Project Spruce. We have nine founding institutions that have already achieved a 50% reduction in their emissions from inhaled anesthetics during the first year of this consortium’s existence, and we have new institutions that have joined and are on their way to the same goal.

And then on a personal note, I’m really proud when I hear my kids talking about what I do and how when I take care of kids at the hospital, I’m also helping to take care of the planet.

ANNA ROTHSCHILD: Oh, I love that. That’s so sweet. They must be so proud of you.

ELIZABETH HANSEN: Thank you.

ANNA ROTHSCHILD: Well, Dr. Hansen, thank you so much for joining me.

ELIZABETH HANSEN: Thank you so much for having me.

ANNA ROTHSCHILD: Dr. Elizabeth Hansen is a pediatric anesthesiologist at Seattle Children’s Hospital in Washington.

Copyright © 2024 Science Friday Initiative. All rights reserved. Science Friday transcripts are produced on a tight deadline by 3Play Media. Fidelity to the original aired/published audio or video file might vary, and text might be updated or amended in the future. For the authoritative record of Science Friday’s programming, please visit the original aired/published recording. For terms of use and more information, visit our policies pages at http://www.sciencefriday.com/about/policies/