Exploring the Environmental Impact of Anesthesia Gas

Anesthesia gas can have a significant impact on the environment if it is not absorbed or disposed of properly.

Modern operating rooms are proactively looking for ways to become more eco-friendly, with an eye on sustainability and carbon neutrality. That's likely because 70 percent of a single hospital's total waste originates from the OR, according to research published in the American Association of Nurse Anesthesiology Journal.1

Breaking this figure down even further, one-quarter of that OR waste can be attributed specifically to anesthesia-related materials.

Understanding How Anesthesiology Produces Waste

In short, it's the anesthesia gas that produces waste. Although the benefits of anesthetic agents largely outweigh the risk to patients, they pose a significant risk to the environment if not absorbed or disposed of properly. For example, isoflurane, sevoflurane, and desflurane are the three most common and effective anesthetic gasses. They are, however, also recognized as greenhouse gasses, which trap heat, damage the earth's ozone layer, and contribute to climate change.

That's because anesthetic gasses undergo very little metabolic change inside the body. According to Anesthesia Progress, patients metabolize less than 5 percent of these gasses; the rest remain in a form that can pollute the environment when exhaled.2 Because little or no degradation occurs before being vented into the outside environment, desflurane or isoflurane can remain in the troposphere—the lowest layer of the atmosphere where greenhouse effects occur—for anywhere from a year to a decade.

Carbon dioxide (CO2) absorbers play a critical role in minimizing waste from these exhaled anesthetic gasses.

Using CO2 Absorbers to Reduce Waste

When under anesthesia, a patient is connected to a closed breathing circuit that helps minimize anesthetic agent use. With each exhaled breath, the patient's expiratory gasses pass through a CO2 absorber canister that removes CO2, thereby allowing the patient to safely rebreathe the anesthetic gas and creating an effective environment for anesthesia delivery.

CO2 absorbents can only draw in so much CO2 before a new canister is needed. It is paramount to dispose of a used CO2 absorber properly—failure to do so can release both CO2 and anesthetic gasses into the atmosphere. High-quality CO2 absorbers make it easy to know how and when to discard them.

Soda Lime

One of the most commonly used CO2 absorbents is soda lime: a mixture of calcium hydroxide and sodium or potassium hydroxide.

Soda lime canisters use a visual color change indicator to signal when their absorptive capacity has been exhausted—usually when the FiCO2 exceeds 0.5 percent volume. However, this color change is not permanent. For example, if the canister is nearly exhausted toward the end of the week and has started to change color, by the following week it could look white again, giving a false impression that it can absorb much more CO2 than it actually can.

Disposing soda lime-based absorbers can be a tricky task. When soda lime degrades sevoflurane and desflurane, it creates carbon monoxide, compound A, and formaldehyde inside its absorber canister. If inadvertently inhaled by waste management—or even anesthesia patients themselves—these gasses can deprive the body of oxygen and cause neurologic injury.3

GE Healthcare's AMSORB Plus

Comparatively, GE Healthcare's AMSORB™ Plus does not degrade sevoflurane and desflurane. Nor does it produce compound A, formaldehyde, or carbon monoxide, removing the risk that patients and staff will inhale these harmful byproducts. AMSORB Plus is also non-hazardous and therefore can be disposed of with uncontaminated clinical waste; it breaks down into harmless, organic compounds and is safe to handle.

Additionally, the purple color change of AMSORB Plus is permanent and irreversible to accurately indicate its hydrated status. This eco-friendly option not only improves patient care but also reduces the potential for harm to the environment.

Going Green in the OR

The environmental impact of healthcare waste affects patients, healthcare facilities, and entire communities. Prioritizing reducing the release of anesthetic agents during surgery is crucial for minimizing harm to patients and the planet alike.

With proper waste management training and education, surgical staff can help reduce the improper disposal of supplies. And with innovative product solutions that solve the imperfections of materials like soda lime, healthcare manufacturers can help operating rooms across the country go a little more green every day.

References

1. https://www.aana.com/docs/default-source/aana-journal-web-documents-1/operating-room-waste-reduction-december-2019.pdf?sfvrsn=a05c213f_4

2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3522493/

3. https://downloads.hindawi.com/archive/2011/730483.pdf