These systems, exemplified by EtC, facilitate automation and precise adjustments in anesthetic and oxygen gas composition and flow rates to meet clinical targets set by providers By optimizing anesthetic delivery, semi-closed loop systems can decrease the consumption of anesthetic gases during surgical procedures, thus contributing to environmental sustainability and the potential for cost savings.
One of the researchers, Dr. Ross Kennedy2, provides additional insight into the background of the study, and offers his clinical perspectives on the significance of the findings:
Why did you take interest in this particular research?
Dr. Kennedy: This is an area I’ve been interested in for several decades. Matching delivery closely with patient needs is intellectually satisfying, and even 25 years ago, we showed the dramatic cost savings from modest reductions in FGF when using sevoflurane, along with notable environmental footprint changes. I’ve also had a long interest in pharmacokinetics and pharmacodynamics, applying insights from intravenous agent delivery to inhaled agents, and exploring concepts like the delay between end-tidal and “brain” concentrations. With the introduction of Propofol TCI in our market in 1996, most modern TCI systems began displaying both estimated “effect site” and plasma concentrations. All of this meant that when EtC was introduced to our market, coinciding with our need to update a significant portion of our anesthesia machine fleet, the department’s interest and knowledge made these machines a perfect fit. Since then, my interest in these areas has continued unabated.
Can you provide a brief summary of the study conducted?
Dr. Kennedy: The study conducted a focused literature review to assess the environmental and economic outcomes of EtC compared to standard care (manual clinician adjustments of gas flows and anesthetic agents). The review included studies published between January 1, 2013, and February 28, 2023, identified through electronic database searches and manual retrieval methods. Our team used terms such as “End-tidal Control,” “closed loop anesthesia delivery,” and “automated anesthesia delivery” for the search. Additionally, studies cited by identified publications, review papers, and communications with relevant experts/principal investigators were included.
What were the top three key findings?
Dr. Kennedy: Our key findings highlight the environmental, economic, and clinical benefits. We now know that anesthetic gases such as sevoflurane, isoflurane, and desflurane, commonly used in anesthesiology, contribute significantly to greenhouse gas emissions. Semi-closed loop systems like EtC reduce anesthetic gas consumption, resulting in a substantial decrease in greenhouse gas emissions equivalent to eliminating the annual emissions of approximately 100 U.S. motor vehicles. We also found that utilizing EtC instead of manual adjustments for anesthesia delivery leads to cost savings for anesthetic agents. The estimated annual cost-savings for a large academic medical center using EtC is approximately $95,536, primarily due to reduced usage of desflurane, followed by sevoflurane. Finally, EtC offers clinical benefits by reducing manual repetitive tasks required of providers, delivering a more stable, accurate, and precise anesthetic at lower flows than manual administration. It may reduce anesthetic agent usage by up to approximately 32% compared to manual administration, enhancing patient safety and comfort.
Can you offer your perspective on the clinical significance of the research, especially as it relates to its introduction into the United States?
Dr. Kennedy: These findings match our own experience and data since we introduced EtC more than ten years ago. Essentially, automated control of agent delivery results in dramatic reduction in vapour consumption while reducing workload. Although some people have concerns about deskilling and delegating tasks to a machine, I see this type of technology as empowering for clinicians. It allows us to focus more on the patient instead of needing to pay attention to the fiddly and intricate details of adjusting gas flows and vapour settings.
Conclusion
The literature review reveals that EtC’s automation of end tidal O2 and inhalational anesthetic agent delivery demonstrates noticeable economic and environmental benefits. It may reduce volatile anesthetic agent usage during inhaled anesthetic administration. Automation of end tidal O2 and inhalationalanesthetic agent delivery also reduces workload associated with manual gas adjustments. Therefore, its adoption in clinical practice may not only contribute to cost savings and environmental sustainability by reducing greenhouse gas emissions, but also to workload efficiency, highlighting its potential as a key technology in modern anesthesiology.
*End-tidal Control in the United States is indicated for patients 18 years of age and older.
References
- Beard J, Kennedy R, Philip J, Erslon M, Jiao W, Hyatt H, Yapici H. Environmental and Economic Impacts of End-tidal Control of Volatile Anesthetics: A Scoping Review and Analysis. Open Anesthesia J, 2025; 19: e25896458355905. http://dx.doi.org/10.2174/0125896458355905241230090118
- Dr. Kennedy is a paid consultant for GE HealthCare and was compensated for participation in this paper. The statements by Dr. Kennedy described here are based on his own opinions and on results that were achieved in his unique setting. Since there is no “typical” hospital/clinical setting and many variables exist, i.e. hospital size, case mix, staff expertise, etc., there can be no guarantee that others will achieve the same results.
GE is a trademark of General Electric Company used under trademark license. Aisys is a trademark of GE HealthCare.
Nothing in this material should be used to diagnose or treat any disease condition. Readers must consult a healthcare professional.
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