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1. Anesth Analg. 2021 Oct 1;133(4):826-835. doi: 10.1213/ANE.0000000000005504.
Environmental and Occupational Considerations of Anesthesia: A Narrative Review 
and Update.
Varughese S(1), Ahmed R.
With an estimated worldwide volume of 266 million surgeries in 2015, the call 
for general inhalation anesthesia is considerable. However, widely used volatile 
anesthetics such as N2O and the highly fluorinated gases sevoflurane, 
desflurane, and isoflurane are greenhouse gases, ozone-depleting agents, or 
both. Because these agents undergo minimal metabolism in the body during 
clinical use and are primarily (≥95%) eliminated unchanged via exhalation, waste 
anesthetic gases (WAGs) in operating rooms and postanesthesia care units can 
pose a challenge for overall elimination and occupational exposure. The chemical 
properties and global warming impacts of these gases vary, with atmospheric 
lifetimes of 1-5 years for sevoflurane, 3-6 years for isoflurane, 9-21 years for 
desflurane, and 114 years for N2O. Additionally, the use of N2O as a carrier gas 
for the inhalation anesthetics and as a supplement to intravenous (IV) 
anesthetics further contributes to these impacts. At the same time, unscavenged 
WAGs can result in chronic occupational exposure of health care workers to 
potential associated adverse health effects. Few adverse effects associated with 
WAGs have been documented, however, when workplace exposure limits are 
implemented. Specific measures that can help reduce occupational exposure and 
the environmental impact of inhaled anesthetics include efficient ventilation 
and scavenging systems, regular monitoring of airborne concentrations of waste 
gases to remain below recommended limits, ensuring that anesthesia equipment is 
well maintained, avoiding desflurane and N2O if possible, and minimizing fresh 
gas flow rates (eg, use of low-flow anesthesia). One alternative to volatile 
anesthetics may be total intravenous anesthesia (TIVA). While TIVA is not 
associated with the risks of occupational exposure or atmospheric pollution that 
are inherent to volatile anesthetic gases, clinical considerations should be 
weighed in the choice of agent. Appropriate procedures for the disposal of IV 
anesthetics must be followed to minimize any potential for negative 
environmental effects. Overall, although their contributions are relatively low 
compared with those of other human-produced substances, inhaled anesthetics are 
intrinsically potent greenhouse gases and pose a risk to operating-room 
personnel if not properly managed and scavenged. Factors to reduce waste and 
minimize the future impact of these substances should be considered.
DOI: 10.1213/ANE.0000000000005504
PMCID: PMC8415729
PMID: 33857027 [Indexed for MEDLINE]
2. AANA J. 2022 Aug;90(4):253-262.
Reducing the Carbon Footprint of Anesthesia: Low-Flow Anesthesia and Other 
Techniques.
McGowan LS(1), Macksey LF(2).
According to a joint statement by the US National Academy of Sciences and the UK 
Royal Society, it is now more certain than ever that human activity is a leading 
cause of rapid, accelerated climate change. Our volatile anesthetics have up to 
2,000 times more greenhouse gas contributing potential than the same amount of 
carbon dioxide, yet no emission regulations have been imposed. The carbon 
footprint of volatile agents exists in all anesthesia practices, indirectly 
affecting all humans. It manifests daily in the clinical practice of over 30,000 
certified registered nurse anesthetists in the United States, as their 
anesthetic choices directly impact the environment. However, education about 
anesthetic choice and its impact has been overlooked, making many anesthesia 
providers unaware of meaningful ways to reduce ecological and economic costs. 
Decreasing the use of volatile agents by low-flow techniques and the use of a 
total intravenous anesthetic could dramatically reduce carbon footprint produced 
by anesthesia. The authors review other advantages of limiting or avoiding 
volatile agents beyond green anesthesia such as decreased costs, reduced 
postoperative nausea and vomiting, and lowering the risk of malignant 
hyperthermia.
PMID: 35943750 [Indexed for MEDLINE]
3. AANA J. 2021 Feb;89(1):27-33.
Evidence-Based Project: Cost Savings and Reduction in Environmental Release With 
Low-Flow Anesthesia.
Edmonds A(1), Stambaugh H(2), Pettey S(3), Daratha KB(4).
Volatile anesthetic agents act as greenhouse gases. Low-flow anesthesia 
techniques (≤1 L/min) are associated with lower costs. Decreasing volatile 
anesthetic delivery provides safe and effective strategies for anesthesia 
providers to decrease costs and reduce environmental pollution. This 
evidence-based project aimed to estimate cost savings and reduction in the 
environmental release of anesthetic gases, under simulated lower fresh gas flow 
(FGF) practices. For each surgical case, the exhaled anesthetic gas percent and 
FGF data were used to calculate the volume of fluid volatile anesthetic. The 
fluid volatile anesthetic for each case was then estimated using simulated FGFs. 
Changes in volatile agent cost and environmental release of anesthetic gases 
were predicted. Sevoflurane was the most commonly used volatile agent. The mean 
FGF for cases using sevoflurane was 2.5 L/min. The simulated FGF of 1 L/min FGF 
across all agents predicted a 48% ($50,892) reduction in costs of volatile 
anesthetics and a 42% (33 metric tons of carbon dioxide equivalent) decrease in 
carbon emissions. Simulated low-flow anesthesia demonstrated cost savings and 
environmental conservation. Project findings align with current literature 
showing that lowering FGFs represents an area of cost containment and an 
opportunity to lessen the environmental impact of anesthesia.
PMID: 33501906 [Indexed for MEDLINE]
4. Pediatr Qual Saf. 2023 Dec 12;8(6):e708. doi: 10.1097/pq9.0000000000000708. 
eCollection 2023 Nov-Dec.
Sustainability Standards in Pediatric Anesthesia: Quality Initiative to Reduce 
Costly Environmentally Harmful Volatile Anesthetics.
Waberski AT(1), Pestieau SR(1), Vazquez-Colon C(1), Cronin J(1), Braffett BH(2).
BACKGROUND: The emission and entrapment of greenhouse gases (GHG) inside the 
atmosphere is one of the leading causes of global warming. Commonly administered 
anesthetics have global warming potential up to 2,000 times greater than carbon 
dioxide. This Quality Improvement (QI) initiative aimed to develop a set of 
sustainability standards to reduce volatile anesthetic GHG emissions and costs 
at a children's hospital.
METHODS: In January 2020, the QI project team implemented education sessions for 
clinical staff on the environmental impact of volatile anesthetics, bedside 
clinical reminders, resource guides on sustainable anesthesia practices, preset 
low-flow gas levels on anesthesia machines, relocated and reduced the number of 
available vaporizers, and implemented policies to standardize clinical practice. 
Using hospital pharmacy purchase order data between 2018 and 2022, GHG emissions 
and costs from three commonly used volatile anesthetics (Isoflurane, 
Sevoflurane, and Desflurane) were compared using metric ton carbon dioxide 
equivalents.
RESULTS: During 3 years, GHG emissions from volatile anesthetics were 
significantly reduced by 77%, with most of the reduction attributed to the 
reduced use and eventual elimination of Desflurane. Purchase costs were also 
significantly reduced during this period by 41%.
CONCLUSIONS: This QI project successfully decreased GHG emissions over 3 years 
by simultaneously reducing the use of costly and environmentally harmful 
volatile anesthetic, Desflurane, and increasing the use of low-flow anesthesia. 
This study addresses our anesthesia practices and healthcare system's impact on 
the pediatric population and proposes simple interventions to mitigate the 
negative consequences of current practices.
DOI: 10.1097/pq9.0000000000000708
PMCID: PMC10715793
PMID: 38089832
5. Can J Anaesth. 2023 Mar;70(3):301-312. doi: 10.1007/s12630-022-02393-z. Epub 
2023 Feb 22.
A call for immediate climate action in anesthesiology: routine use of minimal or 
metabolic fresh gas flow reduces our ecological footprint.
Rübsam ML(1), Kruse P(2), Dietzler Y(3), Kropf M(4), Bette B(2), Zarbock A(5), 
Kim SC(2), Hönemann C(6)(7).
PURPOSE: Climate change is a global threat, and inhalational anesthetics 
contribute to global warming by altering the photophysical properties of the 
atmosphere. On a global perspective, there is a fundamental need to reduce 
perioperative morbidity and mortality and to provide safe anesthesia. Thus, 
inhalational anesthetics will remain a significant source of emissions in the 
foreseeable future. It is, therefore, necessary to develop and implement 
strategies to minimize the consumption of inhalational anesthetics to reduce the 
ecological footprint of inhalational anesthesia.
SOURCE: We have integrated recent findings concerning climate change, 
characteristics of established inhalational anesthetics, complex simulative 
calculations, and clinical expertise to propose a practical and safe strategy to 
practice ecologically responsible anesthesia using inhalational anesthetics.
PRINCIPAL FINDINGS: Comparing the global warming potential of inhalational 
anesthetics, desflurane is about 20 times more potent than sevoflurane and five 
times more potent than isoflurane. Balanced anesthesia using low or minimal 
fresh gas flow (≤ 1 L·min-1) during the wash-in period and metabolic fresh gas 
flow (0.35 L·min-1) during steady-state maintenance reduces CO2 emissions and 
costs by approximately 50%. Total intravenous anesthesia and locoregional 
anesthesia represent further options for lowering greenhouse gas emissions.
CONCLUSION: Responsible anesthetic management choices should prioritize patient 
safety and consider all available options. If inhalational anesthesia is chosen, 
the use of minimal or metabolic fresh gas flow reduces the consumption of 
inhalational anesthetics significantly. Nitrous oxide should be avoided entirely 
as it contributes to depletion of the ozone layer, and desflurane should only be 
used in justified exceptional cases.
DOI: 10.1007/s12630-022-02393-z
PMCID: PMC10066075
PMID: 36814057 [Indexed for MEDLINE]
6. Paediatr Anaesth. 2020 Oct;30(10):1139-1145. doi: 10.1111/pan.13994. Epub 2020 
Aug 29.
The implementation of low-flow anesthesia at a tertiary pediatric center: A 
quality improvement initiative.
Glenski TA(1), Levine L(1).
INTRODUCTION: Anesthesia machines have evolved over the years to excel in 
delivering low-flow anesthesia (<1 L fresh gas flow) in a closed-circuit system, 
with the obvious benefits being decreased costs and reduced emissions of 
greenhouse gases. At a pediatric hospital that provides over 25 000 anesthetics 
a year, a quality improvement project was initiated with the aim of decreasing 
the amount of sevoflurane used per anesthetic by 20% over the course of a year.
METHODS: Three Plan-Do-Study-Act cycles involving gathering comparative data, 
departmental education, improvement updates on our huddle board, and 
intraoperative confirmation rounds were completed. The bottles of sevoflurane 
used and the total number of anesthetics performed were collected each month. To 
account for the fluctuation of anesthetic cases per month, a metric of 
"Anesthetics Performed per Bottle of Sevoflurane Used" was created.
RESULTS: Compared to a prior twelve-month period, the Anesthetics Performed per 
Bottle of Sevoflurane Used were higher with a mean increase of 25%. The bottles 
of sevoflurane used per month was lower with a mean decrease of 20%. The carbon 
footprint of our sevoflurane use was also decreased and extrapolated over a 
year, and the decrease was equivalent to 70 000 miles driven, over 3,200 gallons 
of gasoline consumed, or over 31000 pounds of coal burned.
CONCLUSION: A QI initiative aimed at changing the practice of delivering at 
least 2L fresh gas flow to delivering a low-flow anesthetic has been a 
successful value-added enhancement to our pediatric anesthesia practice.
DOI: 10.1111/pan.13994
PMID: 32786105 [Indexed for MEDLINE]
7. J Grad Med Educ. 2024 Apr;16(2):175-181. doi: 10.4300/JGME-D-23-00402.1. Epub 
2024 Apr 15.
How an Audit-and-Feedback-Based Educational Program Contributed to a Reduction 
in Environmentally Harmful Waste Anesthetic Gases Among Anesthesiology 
Residents.
Nordin EJ(1), Dugan SM(2), Kusters AC(3), Schimek CA(4), Sherman KA(5), Ebert 
TJ(6).
Background Waste anesthetic gases (WAGs) contribute to greenhouse gas emissions. 
US anesthesiology resident education on how to reduce WAG-associated emissions 
is lacking, so we developed an electronic audit-and-feedback-based program to 
teach residents to reduce fresh gas flow (FGF) and WAG-associated emissions. 
Objective To assess the program's effectiveness, we measured individual and 
combined mean FGF of residents during their first, second, and last weeks of the 
4-week rotation; then, we calculated the extrapolated annual emissions based on 
the combined resident mean FGFs. Resident attitudes toward the program were 
surveyed. Methods During 4-week rotations at a teaching hospital, anesthesia 
records were scanned to extract resident-assigned cases, FGF, and volatile 
anesthetic choice during the 2020-2021 academic year. Forty residents across 3 
training years received weekly FGF data and extrapolated WAG-associated 
emissions data via email. Their own FGF data was compared to the low-flow 
standard FGF of ≤1 liter per minute (LPM) and to the FGF data of their peer 
residents on rotation with them. An online survey was sent to residents at the 
end of the project period. Results Between their first and last weeks on 
rotation, residents decreased their mean FGF by 22% (1.83 vs 1.42 LPM; STD 0.58 
vs 0.44; 95% CI 1.67-2.02 vs 1.29-1.56; P<.0001). Ten of 18 (56%) residents who 
responded to the survey reported their individual case-based results were most 
motivating toward practice change. Conclusions An audit-and-feedback-based model 
for anesthesiology resident education, designed to promote climate-conscious 
practices with administration of volatile anesthetics, was effective.
DOI: 10.4300/JGME-D-23-00402.1
PMCID: PMC11234298
PMID: 38993317 [Indexed for MEDLINE]
8. Br J Anaesth. 2024 Jul 22:S0007-0912(24)00389-1. doi: 10.1016/j.bja.2024.06.024. 
Online ahead of print.
Efficient inhaled anaesthetic delivery requires managing fresh gas flow from 
induction through emergence.
Feldman JM(1), Sherman JD(2).
DOI: 10.1016/j.bja.2024.06.024
PMID: 39043522