Disclosures
Consultant for GE Healthcare
Environmental Impact of Anesthesia
Jodi D. Sherman, MD
Associate Professor of Anesthesiology,
and Epidemiology in Environmental Health Sciences
Yale Schools of Medicine, and Public Health
@GreeningDoc
Art A&A 5/12
Learning Objectives
• Discuss the relationship
between pollution and public
health
• Define Life Cycle Analysis (LCA)
• Summarize key inhaled
anesthetic pollution findings
• Identify opportunities for
anesthesiology practice
improvement
Disclosure: no relationships with industry
@GreeningDoc
#ClimateChange #ASA2019 #ClinicalSustainable
Why sustainability?
• We live in a finite world
• Human health is dependent on environmental health
“Climate Change is a Medical Emergency”
Lancet Commission on Health and Climate Change,
WHO, UN
7000+ higher education institutions, 6 continents
Pollution a leading cause of
non-communicable disease/deaths
• 9 million premature deaths,
16% of all global deaths
• Disproportionately affects
the poor
• Air pollution and climate
change closely linked
• Welfare losses estimated at
$4.6 TRN/year, 6.2% global
output.
• Cost of inaction high, while
ROI for pollution control
significant
Lancet Commission on Pollution and Health, 2018
”Climate change will be the defining
issue for health systems in the 21st
Century. Health Professionals have the
knowledge, cultural authority, and
responsibility to protect health from
climate change.“
Margaret Chan, MD, Director General, World Health Organization
Intergovernmental Panel on Climate Change
Special Report on Global Warming of 1.5°C
October 8, 2018
www.climateactiontracker.org
• Already seeing harm from
1°C global warming
• Likely to reach 1.5°C
between 2030-2052
• Anthropogenic CO2
emissions need to fall by
45% by 2030
, and reach
‘net zero’ by 2050 to limit
to 1.5°C by 2100
• Possible within laws of
chemistry and physics.
Unprecedented in scale
“The next few years are probably the most important in all of human history.”
Debra Roberts, IPCC Co-Chair
Life Cycle Assessment (ISO 14040)
9
Environmental impacts can occur at each stage of the life cycle and can be non-intuitive
Need to consider all stages in order to inform large-scale design or policy decisions
Need to consider multiple environmental impacts, to ensure that we are not simply
shifting burdens from one impact to another
Courtesy M. Eckelman
• If health care were a country,
it would rank 13
th
in the world
for GHG emissions
• US health care public health
damages from pollution
614,000 DALYs (especially air
pollution + climate change)
• Similar in magnitude as the
44,000-88,000 deaths due to
medical errors
• Pollution prevention the new
patient safety movement
Eckelman, Sherman, PLoS ONE 2016
Eckelman, Sherman, Am. J. Public Health 2017
US health sector
10% of national GHGs emissions
In Press: Courtesy Matt Eckelman, PhD
Global healthcare sector GHG emissions
4.6% of global total emissions
(2250 Mt CO2e) in 2016
Relative National Health Sector
GHG emissions in NHS-England
Sustainable Development Unit, NHS
2013 report
• Major categories:
– building energy use
– Travel (staff and patients)
– Procurement
• 2.5% GHG emissions from
anesthetic gases (in the
UK, especially N
2
O)
• 5% of acute care
organization carbon
footprint from anesthetic
gases
Clinical Sustainability is central
to the aims of Quality Improvement
VALUE =
&
+ +
• Deliver maximum
health gain/experience
of care
• At minimal financial
cost
• While adding value at
every opportunity, for
the most people
Sherman, et al., Reducing pollution from the health care industry, JAMA 2019
What happens to inhaled anesthetics?
95% vented out the roof of
the hospital
Destroy ozone layer
Greenhouse gases
Emissions not controlled
Courtesy S. Ryan, UCSF
WAG: One hour of anesthetic like driving a
car….miles
(EPA 2012 USA fuel efficiency average, 23.9 mpg)
1-MAC-hour Sevoflurane
2.2%
Isoflurane
1.2%
Desflurane
6.7%
N
2
O*
0.6-MAC-hr
0.5 L/min XXXX 4 93 29
1.0 L/min 4 7 189 57
2.0 L/min 8 15 378 112
5.0 L/min 19 38 939 282
10.0 L/min 38 74 1,876 564
Courtesy S. Ryan
Free Smart Phone App Calculator!
Life Cycle Assessment (LCA)
Propofol vs. Inhaled Anesthetics
Sherman, Le, Lamers, Eckelman, A&A May 2012
Sherman, Le, Lamers, Eckelman, A&A May 2012
Life Cycle Greenhouse Gases of Anesthetic
Drugs (1-MAC-hr)
Waste phase = pink and red.
Non-waste phases (manufacturing, transportation, use) = blue.
NOTE: Des and Iso @ 1LPM, Sevo @ 2LPM, Prop @ 100 mcg/kg/min (70kg)
What about
Non-inhaled Anesthetics?
• Regional/Peripheral Nerve Blocks
• Neuraxial
• Total Intravenous Anesthesia (TIVA)
20
Life Cycle GHG Emissions of Alternative
Anesthetic Clinical Care Pathways
0.0 10.0 20.0 30.0 40.0 50.0 60.0
MAC
PNB+(TIVA/MAC)
TIVA
MIXED
PNB+GIH
GIH
GHG emissions (kg CO2 eq.)
IV (used)
IV (wasted)
Inhaled
Medical supplies
Sherman, Tunceroglu, Parvatker, Eckelman
MAC=Monitored Anesthesia Care; PNB=Peripheral Nerve Block;
GIH=General Inhaled (Sevo); TIVA=Total Intravenous Anesthesia
APSF project
Environmental impact importance
by time horizon
Lippiat, et al. Environ Sci Technol. 2007;41(21):7551-7557
Sherman, Barrick, ”Pick your poison”, A&A 2018
GHG Emissions and Hysterectomy
Thiel, et al., Environ Sci Technol, 2015
Example that choices matter:
GHG Emissions and Operating
Theatres in Three Health Systems
MacNeill AJ, et al., Lancet Planetary Health 2017
Do we need desflurane?
• Faster wake times for
surgeries < 90”
• Surgeries > 110”,
comparable wake up times
(85% MAC decrement in
VRG)
• Researchers kept at 1-MAC
until very end of surgery
• Faster wake up ➜more $??
– Patient payer mix
– Patient volume
– Staff compensation system
• Eger, et al, Tutorial: Context-Sensitive
Decrement Times for Inhaled Anesthetics,
A&A 2005
• Dexter, et al, Statistical Modeling of Average
and Variability of Time to Extubation for
Meta-Analysis Comparing Desflurane to
Sevoflurane, Dexter, A&A 2010
Yale-New Haven Health System
• Eliminated Desflurane from formulary, 2013
• Saved approximately
• 186,690 kg CO
2e
/year
• 456,455 passenger vehicle miles driven/year
• Sevoflurane use up slightly, isoflurane no
difference; assumed no difference in
TIVA/regional
• Saved $1.2 million across health system/year by
eliminating desflurane drug and
vaporizers
https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator
University of Utah
• Cash challenge: electively cut desflurane use by 50%
• Reduced inhaled anesthetic acquisition costs by
$308,000
• saved WAG GHG equivalent of 5.4 million miles driven
– without increasing their turnover times
– without increasing PACU discharge times
– Propofol usage did not increase
– Isoflurane use did increase
– Sevoflurane use stayed the same
• Behavior change gone within one year
Courtesy H. Hopf, U. Utah
University of Wisconsin
Zuegge, et al, A&A 2019
• Educational campaign
• Info stickers on
vaporizers (point of
decision-making)
• Saved approximately:
• 2,865,430 kg CO
2e
/year
⬇ Desflurane
⬇ N2O
• 7,005,941 passenger
vehicle miles driven/year
• $300,000 in inhaled drug
purchase costs/year
• Behavior change sticking
Changes in use of desflurane and
sevoflurane and carbon emissions
University of British Columbia 7 hospitals
Alexander, et al. CJA 2018
Between 2012-2018, saved 8.9 million kg (66% reduction) = 1,700 cars on the road
0%
20%
40%
60%
80%
100%
Agent Selection (%)
0.0
500.0
1000.0
1500.0
2000.0
2500.0
GHG emissions
(mtCO
2
e)
$0
$100,000
$200,000
$300,000
$400,000
$500,000
$600,000
Cost ($)
Oregon: 8 hospitals
Provider performance reports
Courtesy Brian Chesebro, MD
2016-2018, saved 4,996,172 kg CO2e = 12,156,135 passenger vehicle miles driven
$636,000 per year saved
No difference in out of room time or PACU time
Scaling Up Inhaled Anesthetic Practice
Improvement: The Role of Environmental
Sustainability Metrics
• Removing environmentally offensive options
• Creating barriers, e.g. locking up vaporizers
• Financial incentives
• Educational campaigns
• Point-of-care information: $$, GHG
• Feedback reports
• Financial penalties, e.g. pay-for-performance,
carbon taxes
Sherman and Berkow, A&A 2019
SUS 01: FGFs
• Percentage of cases with mean FGF ≤ 3 L/min,
during admin of inhaled anesthetics
• Inclusion: inhaled anesthetic ≥ 30 min. from
placement of airway device to its removal
• Exclusion:
– Cases in which inhaled anesthetics not used
– Cases with maintenance period < 30 min
– Cases where > 20% of FGF values manually
entered
Courtesy Nirav Shah and Kathryn Buehler
SUS 01: FGFs
Real-time decision support:
AIMS alerts
• if FGFs exceed 1 L/min
• If Sevo, after 2 MAC-hours (between 1-2
L/min, then alert changes to 2 L/min
• Mean FGF reduction from 2.10 L/min to 1.59
L/min) (note: unclear inclusion/exclusion)
• Saved $105,000 in 2010
Nair, et al. Anesthesiology, 2013;118:874-884
• What’s next for sustainability metrics?
– Real-time FGF alerts
– GHG emissions for inhaled anesthetics
– GHG emissions for other drugs
– Non-GHG emissions
– Drug waste
– Overdosing
• CMS pay-for-performance, accountability
• Charcoal: ultra short-term
↓ Occupational exposure
- Absorb and release
• Gas-capturing systems
– Absorb and store
– Potential reuse, storage issue
– Volatiles only
• Gas destruction
– N2O only
• ?? Efficiency
– Only treat what is exhaled
through circuit
– ⇧FGF= ⇩efficiency
WAG Treatment:
don’t vent to the atmosphere!
Environmental Task Force
2020 Challenge! Reduce your facility inhaled
anesthetic greenhouse gas emissions by 50%
1. Utilize low fresh gas flows
2. Avoid high impact inhaled anesthetics:
⬇ Desflurane and Nitrous Oxide
3. Consider intravenous and regional techniques
4. Invest in WAG trapping or WAG destruction technology
https://publichealth.yale.edu/climate/research/conferences/challenge/
