Environmental ImpactOf Anesthetic Gases

John Deutsch, CRNA, MSN

We all use volatile anesthetics in our practice

Hot Button Topic

General Anesthetic Gases and the Global Environment. Anesthesia-Analgesia January 2011

Global Warming Potential of Inhaled Anesthetics: Application of Clinical Use. Anesthesia-Analgesia July 2010

Inhalation Anaesthetics and Climate Change. British Journal of Anaesthesia October 2010

Surgery Operates on Climate, Too. Discovery News Dec. 14 2010.

OR Gases Pose Ecologic Risk, Economic Reward. Anesthesiology News August 2010

This Presentation

Will Raise awareness of the

environmental impact anesthetic gases

Enlighten you on the current consumption of anesthetic gases within Delaware and the United States.

Discuss options to reduce our use of volatile agents and provide a glimpse into the future of scavenged anesthesia gases.

Will not

Prove or disprove the existence of the Greenhouse effect or global warming.

Force anyone into changing their preferred choice of anesthetic gases.

Patients metabolize only a small fraction of the anesthetic gases they receive during surgery; the remainder is vented through a dedicated air vent system in the hospital and dumped into the environment.

95% of this gas is a loss forever, and the hospital has to go into the marketplace and replace it. Hospitals in the U.S. spend over $1 billion a year on anesthetic gases and $2,500 per gallon for sevoflurane*.

* CCHS spends approximately $1907.84 per gallon of Sevo.

Dillon J. Anesthesiology News August 2010

Where do our agents go when the case is over?

According to the World Meteorological Organization (WMO) global climate change is caused primarily by the increased atmospheric concentrations of the major long-lived greenhouse gases CO2, CH4, N2O, and halogenated organic compounds.

Chemically, halogenated volatile anesthetics are closely related to chlorofluorocarbons (CFCs), which are believed to play a major role in ozone depletion and global warming.

Greenhouse Effect A greenhouse gas is one of several gases that can absorb and

emit longwave (infrared) radiation in a planetary atmosphere. This phenomenon is often termed the greenhouse effect.

Of the sunlight that falls on the Earth's surface, approximately 40% of that energy is reradiated upward into the atmosphere in the form of longwave radiation.

Approximately 75% of that upward radiated longwave energy is absorbed by water vapor, carbon dioxide, methane and other halogenated organic compounds.

As a result, about 50% of the longwave emission is reradiated back toward the Earth where it is once again turned into heat energy.

Through this process, greenhouse gases contribute to the amount of heat energy released at the Earth's surface and in the lower atmosphere.

Greenhouse Gases

South Philly Hair

Carbon Dioxide

Before 1700, levels of carbon dioxide were about 280 ppm (parts per million). Concentrations of carbon dioxide in the atmosphere are now about 390 ppm.

This increase in carbon dioxide in the atmosphere is mainly due to activities associated with the Industrial Revolution. Emissions from the combustion of fossil fuels account for about 65% of the carbon

dioxide added to the atmosphere.

The remaining 35% is derived from deforestation and the conversion of prairie, woodland, and forested ecosystems primarily into less productive agricultural systems.

Global Warming Potential

Global Warming Potential (GWP20) is a measure of how much a given mass of greenhouse gas contributes to global warming over a specified time period (for this presentation we will use 20yr).

It is a relative scale that compares the contribution of the gas in question to the same mass of CO2.

The GWP20 for CO2 is 1, this allows for a standard comparison of two or more gases.

According to Ryan and Nielson (Anesthesia-Analgesia 2010), various volatile anesthetics have been calculated to have a range of 349 (Sevo), 1401 (Iso), to 3766 (Des) times the 20 yr greenhouse warming potential of carbon dioxide.

GWP20

New GWP Data 2012

Ryan S, Nielsen C. Global warming potential of inhaled anesthetics: application to clinical use. Anesth Analg 2010; 111:92-8

Nitrous Oxide

With an atmospheric lifetime of approximately 114 years, N2O is a remarkably stable gas. N2O traps thermal radiation escaping from the surface of Earth, contributing to the “greenhouse effect”

The global warming potential (GWP) of N2O is approximately 289 times more than that of CO2.

The average concentration of nitrous oxide is now increasing at a rate of 0.2 to 0.3% per year

N2O contributes to both global warming and ozone depletion.

Ishizawa Y. General Anesthetic Gases and the Global Environment. Anesthesia-Analgesia 2011; 112:213-217

There are an estimated 200 million anesthetic procedures around the world each year, Andersen and associates concludes that the total amount of gases released for medical reasons is on par with the annual carbon-dioxide emissions from a million cars or one coal-fired power plant. (2010)

It has been estimated that the total U.S. emissions of inhaled anesthetics have a climate impact equivalent to the yearly emissions of 660,000 tons of CO2.

According to information from Emissions Facts- Greenhouse Gas Emissions from a Typical Passenger Vehicle, a typical passenger care in the USA emits 5.03 tons of CO2 per year.

The environmental impact of using Desflurane to anesthetize a surgical patient for 1 hour is equivalent to 235 to 470 miles of driving!

To offset these emissions, each hospital would have to plant approximately 125,000 trees each year.

As A Point of Reference The University of Michigan, which

performed about 46,000 anesthetic procedures (2009), has an environmental impact of 1000 tons of CO2 (or equivalent to approximately 200 cars for a year). (Andersen et al 2010)

Anesthesia Services, P.A. performed approximately 26,177 general anesthetics at CCHS in 2009 had an environmental impact of approximately 569 tons of CO2 (or about 114 cars in 2009 and 113 cars in 2010).

As A Point of Reference

There were approximately 3,071 general anesthetics performed at Nanticoke Hospital in 2010 which had an environmental impact of approximately 67 tons of CO2 (or about 13 cars in 2010).*

Amount of Anesthetic Gases Used in the CCHS Main ORs

Volume purchased 2010

Isoflurane

298 bottles or 74.5 liters Sevoflurane

1386 bottles or 346.5 liters

Desflurane

2892 bottles or 723 litersTotal 1144 liters

Yearly Cost to Purchase

Isoflurane

$7,163.38/yr

$24/bottle

Sevoflurane

$174,615.86/yr

$126/bottle

Desflurane

$358,909.27/yr

$124/bottle

Total $540,688.51

The most immediate answer to reducing Greenhouse Gas effect

Avoid "unnecessarily high" anesthetic flow rates, particularly with Desflurane. Reduction of FGF to 2 L/min

with Sevoflurane (the lowest in common clinical usage currently)

0.5 to 1 L/min with Desflurane and isoflurane would be the best approximations of ideal FGF rates, unless particular anesthesia machine characteristics dictate higher flows."

Use of BIS monitoring

TIVA

Avoid the use of nitrous oxide unless there is a clinical necessity for it.

Further development and refinement of closed flow anesthetic circuits. The use of volatile agents could

be reduced by 80-90%

Use of Xenon

Advances made in waste gas recycling.

Dr R.C. Prielipp April 15 2010

Ryan S, Nielsen C. Global warming potential of inhaled anesthetics: application to clinical use. Anesth Analg 2010; 111:92-8

Change in Volatile Anesthetic Usage in the Main ORs at CCHS

Gas usage has been reduced just by awareness

Collectively our anesthesia department has reduced the amount of anesthetic vapor that we have purchased by 47% for the first four months after this lecture was initially presented.

Remarkably, we have done so with a 3.1% increase in the total number of General Anesthetics that we performed.

During this time frame (March-June) we have gone from 4.04 General Anesthetics/bottle of agent to 7.92 General Anesthetics/bottle!

Change in Amount of Gas Purchased for CCHS Main ORs

2010 2011

Sevo Des Sevo Des

March 45 258 114 (+250%) 132 (-48.8%)

April 27 240 84 (+311%) 108 (-55%)

May 126 198 90 (-28.5%) 120 (-39%)

June 222 360 108 (-51%) 132 (-63%)

CCHS Current FGF rates

104 randomly collected data from April to June 2011:

Desflurane: 23 out of 40 cases had FGF above 1.5 LPM

Isoflurane: 5 out of 6 cases had FGF above 1.5 LPM

Sevoflurane: 6 out of 58 cases had FGF above 2 LPM

Percent of cases with too high FGF rates:

Desflurane: 57.5%

Isoflurane: 83%

Sevoflurane: 10.3%

July 2011

On July 1st, Jacqueline Dombrowski a SRNA from Drexel University started a Performance Improvement Project to reduce our Fresh Gas Flows in the CCHS Operating Rooms.

She came up with flyers to help remind us to reduce our gas flows.

CCHS FGF after July 1st 2011

211 randomly collected data

points from July to September 2011.

Desflurane 18 out of 63 cases had FGF above 1 LPM

Isoflurane 6 out of 9 cases had FGF above 1 LPM

Sevoflurane 0 of 119 case had FGF above 2 LPM

Percent of case with too high FGF rates:

Desflurane 28.5%

Isoflurane 66%

Sevoflurane 0%

Bispectral Index Monitoring

Is a measure of the level of consciousness by algorithmic analysis of a patient's electroencephalogram during general anesthesia.

Titrating anesthetic agents to a specific BIS during general anesthesia in adults, allows the anesthetist to adjust the amount of anesthetic agent used to the needs of the patient, possibly resulting in a reduction of the amount of volatile anesthetic used.

The Trouble with TIVA

Cost

Drug availability

Ease of use for short procedures

Environmentally speaking

Avoid N2O unless it is clinically necessary.

When is N2O clinically necessary?Inhaled induction of general anesthesia?

Ryan S, Nielsen C. Global warming potential of inhaled anesthetics: application to clinical use. Anesth Analg 2010; 111:92-8

Closed Flow Anesthesia Circuits

Can be difficult to titrate.

Labor intensive and time consuming.

Not possible with all of our current anesthesia machines.

Xenon as an anesthetic

Costly anesthetic Between $10 – 20 per liter

Bulky closed delivery system.

New gas monitors

CO2 expenditure may not offset environmental impact of volatile agents

Deltasorb Anesthesia Collection Service

The Deltasorb Anesthetic Collection Service offers hospitals a cost effective, efficient and environmentally friendly alternative to venting toxic anesthetics into the atmosphere. This service includes:

• A weekly delivery and canister exchange service

This service benefits hospitals, their surrounding communities and the environment.

Blue-Zone’s branded Deltasorb technology selectively captures the inhalation anesthetics before they enter the atmosphere through a filtration process.

The self-sterilizing drugs are then extracted, liquefied, and used as raw materials to produce bulk anesthetic drugs.

They can be sold back into the market to large pharmaceutical companies at less than what it costs the companies to manufacture them

Blue-Zone uses multistage thermal and cryogenic processes to extract anesthetic molecules from vented gases trapped in its Deltasorb canisters

This is done at a central facility.

After purification, the resulting “reclaimed” anesthetic is ready for resale and distribution.

Not in the United States

•Dr Berry at Vanderbilt University has designed a device called the Dynamic Gas Scavenging System (DGSS).•The DGSS can recover 99% of the anesthetics without chemically altering them in the process.•DGSS condenses that gases on site by super cooling them in a self-contained unit outside of the Operating room complex.

• The system is designed to work with any anesthesia machine.

• One system costs $20,000 and can serve up to eight operating rooms.

•According to Dr Berry you can recapture anesthetics for less cost than it takes to make them from scratch.

•Recapturing the anesthetic is possible.

• Reselling the recycled anesthetics is another story.

• The FDA wants the history of every molecule and where it comes from.

•However, these gases can be packaged and sold to other countries to offset operating costs.