Percentage of adult cases where nitrous oxide is avoided during anesthesia

Inhalational agents (halogenated hydrocarbons and nitrous oxide) leaking or vented into the atmosphere are environmental pollutants with significant global warming potential. ^1-7

N₂O is both a potent greenhouse gas and an ozone depleting agent. N₂O has an atmospheric lifetime of 114 years, the longest of the commonly used inhaled agents. Thus, the use of N₂O as a carrier gas compared to air/oxygen substantially increases the global warming impact in the operating room.

Eliminating the use of nitrous oxide in the operating room can decrease occupational exposure, public health harm, and cost of anesthesia without compromising patient care.

Table adapted from American Society of Anesthesiologists’ Task Force on Environmental Sustainability Committee on Equipment and Facilities: Greening the Operating Room and Perioperative Arena: Environmental Sustainability for Anesthesia Practice2

*Nitrous oxide value is derived as an average of the range provided on the EPA website: 265-298.

Anesthesia Start to Anesthesia End

Adult patients undergoing any procedure requiring anesthesia. 

Age <18 years

Nitrous oxide was not administered during Anesthesia Start to Anesthesia End

Values for flows and inhalational agents will be assessed and considered as artifact if inside the following ranges:

• Nitrous Oxide Flows: <0.2 L/min
• Nitrous Oxide Insp % <20% 

*This measure will include valid MPOG cases defined by the Is Valid Case phenotype.

Not applicable

Provider(s) signed in when nitrous oxide was administered

1. Epa US, OAR: Understanding global warming potentials 2016 at <https://www.epa.gov/ghgemissions/understanding-global-warming-potentials>
2. Andersen MPS, Nielsen OJ, Wallington TJ, Karpichev B, Sander SP: Assessing the Impact on Global Climate from General Anesthetic Gases. Anesthesia & Analgesia 2012; 114:1081
3. Eisenkraft JB, McGregor DG: Waste Anesthetic Gases and Scavenging Systems 2013:pp 125–47 doi:10.1016/b978-0-323-11237-6.00005-4
4. Feldman JM: Managing fresh gas flow to reduce environmental contamination. Anesth Analg 2012; 114:1093–101.
5. McGain F, Muret J, Lawson C, Sherman JD: Environmental sustainability in anaesthesia and critical care. Br J Anaesth 2020; 125:680–92. 
6. Greening the Operating Room at <https://www.asahq.org/about-asa/governance-and-committees/asa-committees/environmental-sustainability/greening-the-operating-room>.
7. Varughese, Shane MD; Ahmed, Raza MD. Environmental and Occupational Considerations of Anesthesia: A Narrative Review and Update. Anesthesia & Analgesia: October 2021 - Volume 133 - Issue 4 - p 826-835.