The Environmental Impact of Using a CO2 Absorber during Anesthesia

July 22 , 2022 . 3 min read

Although anesthesia is a critical part of most surgeries, it has a negative impact on the environment. Inhaled anesthetics are actually a form of greenhouse gas that can be destructive to the ozone layer. However, because they are considered medically essential, these emissions are not regulated.

One way to lessen anesthesia's environmental impact of these emissions is to use a CO₂ absorber. Further, using GE Healthcare's AMSORB™ Plus CO₂ absorber over the common option of soda lime can contribute to a more eco-friendly hospital and safer anesthesia processes for patients.

Let's examine the factors—both environmental and human—underpinning this important topic.

Understanding the Environmental Impact of Anesthesia Gas

The United States is the second-largest emitter of greenhouse gases globally, and the healthcare sector is responsible for 10% of those emissions, reports an article published in Anesthesiology Clinics.¹In the United Kingdom, inhalation anesthetic gases account for 5% of National Health Service CO₂ emissions, according to the Association of Anaesthetists², with each operating theater producing around 5,070 lbs of anesthetics waste every year.

The most commonly used inhaled anesthetic gases—isoflurane, sevoflurane, and desflurane—undergo very little metabolic change inside the body. When they are exhaled by the patient, the anesthetic agents remain in a form that is potentially pollutive to the environment.

Desflurane is especially potent. According to an article published in The Lancet Planetary Health³, the use of desflurane for one hour is equivalent to driving a modern car for 230 miles.

Tracing the Importance of CO₂ Absorbers

CO₂ absorbers have been a staple of anesthesia since the 1920s. When a patient exhales carbon dioxide and anesthesia gas into their breathing tubes, it travels to a CO₂absorber canister. Then, when a patient inhales, the CO₂-containing anesthesia gas passes through the CO₂ absorber, which (as its name suggests) absorbs the CO₂and removes it from the gas.

This process allows any exhaled anesthetic agents to be rebreathed, which in turn minimizes waste, according to the journal Anesthesia Analgesia.⁴ This limits both the level of anesthetic agents needed to perform surgery as well as the level of gases that are then vented out of the hospital and into the atmosphere. Additionally, patients are secure from the dangers of inhaling carbon dioxide and other harmful gases.

In sum, CO₂ absorbers help surgeries continue in an effective, efficient, and safe way. And they have been doing so for decades.

Weighing Different CO₂ Absorber Options

GE Healthcare's AMSORB Plus and soda lime are two of the most well-known CO₂ absorbers. They both have their pros and cons—highlighting the importance of assessing each option's potential impact on both the hospital and the larger environment.

Soda Lime

Soda lime is one of the most commonly used absorbents for carbon dioxide, likely because it has a relatively low cost of production. However, soda lime degrades anesthetic gases sevoflurane and desflurane, creating compound A and carbon monoxide in its canisters. These dangerous gases can then be easily inhaled by patients, starving their bodies of oxygen.

In addition, soda lime carries the potential to introduce more carbon dioxide to a patient's system, rather than less. How is this possible? When CO₂ reacts with soda lime, it forms heat and water, which causes the pH of the soda lime to change. Ethyl violet is a pH-activated color indicator commonly added to the granules of soda lime inside its CO₂ absorber canister; a color change from white to violet signals that the absorptive capacity of the soda lime has been exhausted and needs to be replaced.

Yet in some cases, this color change may not happen quickly enough—leaving high levels of carbon dioxide⁵ in a canister and putting patient safety at risk.

AMSORB Plus

GE Healthcare's AMSORB Plus is an eco-friendly CO₂ absorption option that takes the basics of CO2 absorption and builds on them to improve patient care during anesthesia treatment.

It doesn't contain any strong alkali and is incapable of degrading harmful anesthetic agents such as desflurane.
It does not produce carbon monoxide, formaldehyde, or compound A, removing the risk that these harmful byproducts will be inhaled by patients.
It is nonhazardous and therefore can be disposed of with uncontaminated clinical waste in accordance with local waste policies.
It breaks down into harmless, organic compounds, making it safer to handle and dispose of.

Most importantly, GE's AMSORB Plus is optimized for low flow anesthesia delivery, which uses fewer anesthetic agents and emits less gas into the atmosphere. This is not only an environmental advantage but a cost benefit as well. Reducing fresh gas flow from high flow (3.0 L/min) to low flow (1.0 L/min) results in savings of about 50% of the total consumption of any volatile anesthetic agent.

Protecting Patients and the Environment

CO₂ absorbers are a crucial part of anesthesia, but facilities cannot overlook their environmental toll. Replacing soda lime with AMSORB Plus better enables teams to care for patients and communities alike, handing them an anesthesia process that is both safer during treatment and easier on the environment.

*Amsorb is a registered trademark of Armstrong Medical Ltd.