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Reducing Fresh Gas Flow With An Eye On Sustainability

Did you know that, as anesthesia professionals, we have the power to significantly impact our environment without compromising our quality of care?

Sustainability has become a major global initiative that is rapidly working its way into healthcare. This is why it is essential to understand that the new practice modifications discussed below, and in other issues to follow, are indeed the future of anesthesia delivery.

These new sustainability-focused anesthesia practice modifications will undoubtedly become the standard of care in hospitals and outpatient facilities everywhere as they seek to reduce their carbon footprints. And as an added perk, facilities providing anesthesia will also benefit from cost reduction, given their markedly reduced use/waste of volatile agents and other medical/pharmaceutical items.

While some of you may think, “These concepts are nothing new,” others may be apprehensive about the sustainability practice changes on the horizon. With our specific guidance and helpful suggestions, we hope readers will quickly acclimate to these practice changes and adopt them into their daily anesthesia care plan.

In this first Sustainability in the OR blog post, you’ll learn how to apply low-flow anesthesia maintenance, which is our single best clinical practice to make the greatest impact toward protecting our planet from the effects of our global warming volatile anesthetics.

Read on to learn how and why you should make the effort.

Three components for safe delivery of low fresh gas flows

During the maintenance of anesthesia with volatile anesthetics (greenhouse gases, or GHG), be sure to do the following. These are simple steps that can yield big results.

    If your hospital ORs don’t yet have AMSORB or other < 2% NaOH CO2 absorbent, you need to obtain it. Why? So you can run low flow Sevoflurane without having concern about producing Compound A.
    While most of you are eliminating routine 2 L/M total fresh gas flows (FGF) in exchange for a maximum of 1 L/M total FGF, I want all providers to understand that we can produce an even more sustainable anesthetic by reducing flows below 1 L/M as long as the bellows fill between each breath. Given the quality of our newer anesthesia machines, all providers can easily and confidently reduce total fresh gas flows to as low as 0.5 – 0.6 L/M most of the time.
    As we reduce fresh gas flows below 1 liter per minute, the FiO2 will typically decline over time. Maintain the FiO2 at a level that provides for adequate SaO2 by increasing the O2 percentage in your fresh gas flow as needed.

Eight key things to remember

    All fresh gas flow (carrying our GHG anesthetic) that exceeds what is needed to fill the bellows is just being “popped off” to our scavenging system and sent out from our rooftop into the atmosphere.
    Some time when you are in the OR, watch the bellows after the ventilator provides a breath. Once the bellows hit the top again, count the seconds, divide by 60, and multiply by your flow in ml/min. This is the volume released to the atmosphere of whatever % volatile agent you are supplying to the circuit with each breath.
    The closer you are to delivering the next breath when the bellows hit the top, the less GHG you allow to be released into the atmosphere. Providers have the opportunity to further reduce flows to the point where the bellows completely fill at or close to the initiation of the next breath.
    As long as the bellows fill, you know your flows are keeping up with system leaks and gas analyzer side-stream sampling. As stated, this practice minimizes waste gas to the environment while still providing an anesthetic equivalent to that with higher flows.
    Recognize that lower fresh gas flows (FGF) will result in declining FiO2 since the volume of rebreathed gases in relation to FGF increases. So, remember to follow the gas analyzer FiO2 to ensure delivery of an adequate FiO2.
    As FiO2 progressively decreases, you may eventually need to dial up the FdO2 settings (FdO2 – “delivered” O2% in your FGF) so that analyzer FiO2 maintains at the desired level for adequate SaO2. The key is ensuring you don’t end up eventually delivering less than 21% (air) or whatever % is needed to maintain the desired SaO2.
    Watch the gas analyzer FiO2 and dial in higher O2% (FdO2) as needed to keep the FiO2 at a level that maintains your SaO2 goal. You should eventually reach a point where the FiO2 stays relatively stable, meaning you have reached equilibrium with the mixture of rebreathed gas and are providing enough additional fresh O2 to meet or exceed the patient’s needs.
    It is important to understand that you DON’T have to increase flows to increase O2 delivery. Just dial in higher O2% (FdO2) for the fresh gas flow joining the rebreathed gas. In the rare case that dialing in 100% O2 is insufficient to maintain adequate oxygenation, that is when you would need to increase flows to push the FiO2 further toward 100%.

Today’s takeaway: Watch the bellows and FiO2

Make sure the bellows hit the top between each breath and dial in enough oxygen to maintain desired FiO2. NOTE: This does not require much additional responsibility during intraoperative anesthesia once you get used to doing it. It really is that simple.

Here at IAA, we’ve comfortably delivered total fresh gas flows at 0.5 L/M intraoperatively with full bellows, FdO2 of 60-65%, and appropriate FiO2/SaO2. This sustainability-focused approach has been easy to implement and is successfully decreasing the carbon footprint of our anesthesiology practice. Give it a try, and let us know how you’re doing.

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APSF low-flow anesthesia education

Become a low-flow anesthesia expert and earn CME’s!

Go to the APSF Education Modual >>

Complete this hands-on low-flow anesthesia education learning module (if you haven’t done so already).  Earn CMEs through

Low-Flow Anesthesia – Anesthesia Patient Safety Foundation
This APSF module will greatly assist you in becoming much more comfortable with the concepts of safe delivery of low-flow anesthesia. Low-flow anesthesia maintenance is the single best clinical practice for us to make the most of our contribution toward protecting our planet.

Please complete this excellent activity and gradually apply what you have learned to your practice.

Join us & spread the word

As always, thank you to all my colleagues, both near and far. I have personally seen a marked change in our utilization of our volatile anesthetics, as well as attempts to reduce our waste streams. As we all benefit from daily efforts, our descendants are benefitting every day as well. As has been said by many individuals in various ways, “We did not inherit this earth . . . . we are borrowing it from our children.”

Do you have a success story you would like to share? Please use the contact information below and get in touch with me. I would love to hear from you.

Until next time, thanks for your continued interest and efforts!

Dr. Adam FischlerAdam Fischler, M.D.
Integrated Anesthesia Associates
Assistant Clinical Professor, Department of Anesthesiology, UCONN Health
Medical Director of the OR, UCONN Health
Section Chief, Regional Anesthesia
Section Chief, Sustainability

Reducing Fresh Gas Flow With An Eye On Sustainability