Sustainability
Workgroup
May 12, 2025
1:00pm - 2:00pm Eastern Time
Introductions and goals for the meeting
Measures discussed at April meeting:
-SUS-01: Fresh Gas Flow, less than or equal to 3 L/min
- SUS-04: Fresh Gas Flow, less than or equal to 2 L/min
- SUS-02: Global Warming Footprint, Maintenance
- SUS-05-Peds: Nitrous Avoided, Induction
Measures to discuss:
SUS-03: Global Warming Footprint, Induction
SUS-06-Peds: Low Fresh Gas Flow, Pediatric Induction
SUS-07: Nitrous Oxide Avoided
Modify measures
- Identify areas identified by the coordinating center to modify measures
- Identify opportunities identified by workgroup to modify measures
Review Literature Updates
Summary and next steps
Agenda
Sustainability Workgroup Members
Name Institution
Brady Still, MD UChicago
Seema Gandhi, MD UCSF
Ben Stam, MD Corewell West & UM West
Eva Lu Boettcher, MD University of Wisconsin
Katie O'Conor, MD, MBA Johns Hopkins
Nick Dalesio, MD Johns Hopkins
Lucy Everett, MD Mass General
Liz Hansen, MD Seattle Children's
Jonathan Paul, D.O. Columbia University
Jodi Sherman, MD Yale
Anjan Saha, MD, PhD Columbia University
Summary from April meeting
Meeting on April 28th
SUS-01 and SUS-04
● Group generally supported a low flow measure (.i.e. Flow < 1 L/min), should be accompanied by a low carbon
footprint measure (update to SUS-02). Consider retiring SUS-01
● Group generally agreed that we should remove exclusion for < 30 minutes so that we can encourage lower flows
for short cases
SUS-02
● Cuveele method - more accurate but may limit participation to fewer sites. The coordinating center will explore
whether more sites can submit MV and end tidal agent concentration data
● Change GWP value from GWP100 to GWP20, as it won’t significantly affect relative performance trend over time,
nor alter recommendations regarding the choice of anesthetic agents or administered flow
● The group agreed on the need for a more detailed analysis of shorter cases - those less than hour - by comparing
them against the per-minute, rather than the per-hour, kg CO2 equivalents of 2% sevoflurane at 2 L/min
Meeting on April 28th
SUS-05-Peds
● The group is considering excluding standard IV inductions given to
minimize score inflation (nitrous oxide is less likely to be used during
induction for IV inductions)
IV Induction - SUS-05 Flagged
Proposed update?
● Create additional induction type value “IV
with volatile agent” (combo).
● If Combo, then include in SUS-05.
● If IV induction or RSI alone, then exclude?
Cuveele query results
for SUS-02
Cuveele’s method to calculate anesthetic agent
● If both fresh gas flow (FGF) and vaporizer dial setting (dialed FVAP) are available, anesthetic agent
consumption can be calculated as a product of FGF and FVAP
● If FVAP is unknown, theoretical model for calculating FVAP, based on FGF, minute ventilation (MV), agent
inspired concentration (FIN), agent end-expired concentration (FET) and dead space ventilation (VD)
● FVAP = [FIN − (dead space fraction * FIN + (1 − dead space fraction) * FET) * (1 − FGF/MV)]/(1-(1 − FGF/MV))
● Dead space fraction for sevoflurane, desflurane, and isoflurane was determined empirically by Cuveele et
al
SUS-02: Inspired/Expired agent and Minute Ventilation
Fill rates (%)
Sevoflurane Isoflurane Desflurane
% Inspired
documented
92.5% 20.9% 14.6%
% Expired
documented
92.1% 23.0% 16.9%
Minute Ventilation
64.3%
Measure Review: SUS-03
SUS-03: Global Warming Footprint, Induction
Description: Total carbon dioxide equivalents per induction for cases where halogenated agents and/or
nitrous oxide was administered during the induction period of anesthesia.
Threshold: Not applicable - informational only
Exclusions:
● Cases in which halogenated hydrocarbons or nitrous oxide are NOT used for induction
● Cases with only manually documented fresh gas flow values (fresh gas flow values must be
automated to be considered for this measure)
Success: Carbon dioxide equivalents will be reported as kilograms of CO2 equivalents per case. A CO2 limit of
50 kg CO2 has been set for this informational measure to ensure that all cases ‘pass’ since a threshold has not
yet be established in the literature.
● Emissions data are also converted to other meaningful equivalencies & reported as:
○ Miles driven by an average gasoline-powered passenger vehicle
○ Gallons of gasoline consumed
SUS-03: Global Warming Footprint, Induction
Miles driven by an average gasoline-powered passenger vehicle (per EPA.gov)
● Convert kg CO2 equivalents to metric tons: Total CO2 / 1000
● Convert metric tons CO2 to miles driven: Metric tons CO2 eq / (0.000403)
Gallons of gasoline (per EPA.gov)
● Convert kg CO2 equivalents to grams of CO2 equivalents: Total kg CO2 * 1000
● Convert grams CO2 eq to gallons of gasoline: Grams CO2 eq / 8,887
SUS-03: Global Warming Footprint, Induction
Other Measure Details:
● Inhalational agents and flows will be assessed and considered as artifact if inside the ranges listed
within the Halogenated Anesthetic Gases and Nitrous Oxide Used phenotypes
● If Fresh Gas Flow Total (Concept ID:3214) is documented for the case, this concept will be used to
determine success of halogenated agents or nitrous oxide use
● If Fresh Gas Flow Total (Concept ID:3214) is not documented for the case, MPOG will calculate
Fresh Gas Flow: Flows Oxygen (ID:3215) + Flows Air (ID:3220) + Flows Nitrous Oxide (ID:3225)
SUS-03 - All MPOG Institutions, May 2024 - March 2025
Mean kg CO2 during induction (0.04 - 13.64)
Measure Review:
SUS-06-Peds
SUS-06-Peds: Low Fresh Gas Flow, Pediatric Induction
Description: Percentage of pediatric cases < 18 years old with a mean fresh gas flow (FGF) equal to or
less than a weight-based threshold during the induction phase of anesthesia.
Threshold: 90%
Exclusions:
● Age > 18 years
● Cases without a valid weight documented
● Cases without fresh gas flow data documented during induction
● Cases in which halogenated hydrocarbons or nitrous oxide are not used during induction
Success Criteria: Mean FGF equal to, or less than the weight-based max FGF (L/min) during the
induction period of anesthesia
SUS-06-Peds: Low Fresh Gas Flow, Pediatric Induction
Other Measure Details:
● If Fresh Gas Flow Total (Concept ID:3214) is documented for the case, this concept will be used to
determine success of halogenated agents or nitrous oxide use
● If Fresh Gas Flow Total (Concept ID:3214) is not documented for the case, MPOG will calculate
Fresh Gas Flow: Flows Oxygen (ID:3215) + Flows Air (ID:3220) + Flows Nitrous Oxide (ID:3225)
● Weight based thresholds:
Weight (kg) Mean FGF
< 20 < 3 L/min
20 - 30 < 4 L/min
30 - 40 < 5 L/min
> 40 < 6 L/min
Current SUS-06-Peds Performance, All MPOG Institutions, May 2024 - March 2025
Performance: 0% - 100%
Measure Review: SUS-07
Current SUS-07 Performance, All MPOG Institutions, May 2024 - March 2025
Recent updates to
literature
Publications
● Beard JW et al., 2025 Environmental and economic impacts of end-tidal control of volatile anesthetics
● Beard JW et al., 2024 Anesthesia delivery via manual control versus end-tidal control
● Cuveele L et al., 2023: Development of validation of a model to calculate anesthetic agent consumption
● Olmos A et al., 2023: Reducing volatile anesthetic waste using a commercial EHR CDS tool to lower FGF
● ASA Committee on Equipment and Facilities, 2023: Statement on the use of low gas flows for sevoflurane
● Sondekoppam RV et al., 2020: The impact of sevoflurane anesthesia on postoperative renal function
● Kennedy RR et al., 2019: There are no dragons: Low-flow anesthesia with sevoflurane is safe
● Brioni JD et al., 2017: A clinical review of inhalational anesthesia with sevoflurane
● Sherman J et al., 2012: Life cycle greenhouse gas emissions of anesthetic drugs
Upcoming changes
Update exclusion logic for SUS-01 and SUS-04
● SUS-01 and SUS-04 calculate mean FGF for the measure based on overlapping time of inhaled
anesthetic agents and fresh gas flow. Example: if there are 30 cumulative minutes halogenated,
but only 24 minutes of fresh gas flow, the mean FGF is then calculated using the 24 minutes of
overlapping time
● Currently, measures exclude cases with < 30 minutes of inhaled anesthetic agents administered
between intubation and extubation
● Future state: cases with < 30 minutes of overlapping inhaled anesthesia agents AND fresh gas
flow will be excluded
● Should we just remove the 30 minute exclusion and include all cases regardless of duration
between intubation and extubation?
Automated FGF logic added to SUS-01 & SUS-04
● The code will first verify documentation of Air
and Oxygen flows for 3 consecutive minutes
(i.e. concepts 0730, 0731, 0732),
● Next, it checks whether there are at least 3
consecutive minutes during which agents
(sevo, des, iso, or nitrous) are being
administered
● Following that, it analyzes whether there are at
least 30 minutes in which both agents and
flows are administered
●If the code returns ‘No’ for any of these
checks, the case is excluded. If a ‘Yes’ is
returned, the case is included and the FGF
value is calculated
Artifact thresholds for inhaled agents
● Low and high artifact thresholds for inhaled anesthetic agents (% or flow) references the
Inhalational Anesthetic Duration phenotype
Thank You!
