









































Volume 5 - No. 1 2017

Educated Hand Publishing LLC 
“The Science Behind the Art” 
Volume 5 - No. 1 2017 

 Anesthesia eJournal - Online
ISSN 2333-2611

Page 1

Environmental Impact of Inhaled Anesthetics: A Literature Review

Jake Margulies, MSN, CRNA
Dirk Bahoravitch, MSN, CRNA
Shawn Collins, PhD, DNP, CRNA
Ian Hewer, MSN, CRNA

Affiliation:
Western Carolina University

Funding/Conflict of Interest Disclosure: 
None

KEYWORDS: environment, inhaled anesthetics, greenhouse gases

INTRODUCTION
Certified registered nurse anesthetists administer nearly 43 million anesthetics in the United States each year.1 Many patients 
receive volatile anesthetics to induce and maintain a satisfactory depth of anesthesia. Volatile anesthetics are also greenhouse 
gases (GHGs).2 Approximately 500,000 gallons of anesthetic GHGs are vented into the environment annually in the United 
States alone, an impact that translates to the GHG emissions of approximately 1 million vehicles annually.2 GHGs serve to 
trap the sun’s radiative energy in the Earth’s atmosphere, contributing to global warming. These wasted anesthetic gases, which 
currently are not commonly recycled or reused, total nearly $1 billion in expenses bared by anesthesia providers and passed on 
to patients and 8% of total carbon dioxide (CO2) emissions3,4 annually in the United States alone.

Current research demonstrates that increasing air pollution causes significant increases in cardiac disease, pulmonary disease, 
and even death—including 16% of lung cancer, 11% of chronic obstructive pulmonary disease, and 20% of ischemic heart 
disease and stroke deaths.5 An estimated 150,000 deaths per year (0.3% of all annual deaths) are said to be related to climate by 
the World Health Organization (WHO), and this number is expected to increase.6 The climate-associated health risks identi-
fied by the WHO include food and water insecurity, increased transmission of infection, heat stress, more frequent and extreme 
weather events, threats to shelter and security, and population migration.7

Because of the medical necessity of volatile anesthetic gases, no prior regulations on emissions have been sought.8 However, 
with the increased number of individuals undergoing surgery and anesthesia and the development of newer anesthetic agents, 
the environmental impacts of these anesthetics should be evaluated.

The purpose of this literature review was to identify, assimilate, and summarize the known impact of volatile anesthetics on the 
Earth’s environment and the global population; to review ways to reduce and eliminate these impacts; and to provide evidence 
supporting the need for changes in current practice and future practice development that can reduce the environmental impact 
and side effects related to volatile anesthetic use.

Abstract
Current research demonstrates that increasing air pollution causes significant increases in cardiac disease, pulmonary dis-
ease, and even death. The known consequences of increasing greenhouse gases parallel those of air pollution and include 
higher rates of cardiovascular disease, asthma, and infectious disease. This literature review aimed to identify, assimilate, 
and summarize the known impacts of volatile anesthetics on the Earth’s environment. We present methods that are being 
used to reduce or eliminate these effects. We also aimed to summarize any known health effects on humans related to 
volatile anesthetic use and to review ways to reduce and eliminate these impacts. It is our hope that this review will pro-
vide evidence that leads to a change in current practice and future practice development that reduces the environmental 
impact and side effects related to volatile anesthetic use.

AEJ



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Volume 5 - No. 1 2017 Page 2

HISTORY AND REVIEW OF THE LITERATURE
This systematic review of the literature began with a thorough 
search for articles relevant to this topic. The databases searched 
included EBSCOhost (EBSCO, Ipswich, MA), Google Scholar 
(Google Inc, Mountain View, CA), and Cochrane Review (The 
Cochrane Collaboration, London, United Kingdom). Search 
terms, used alone and in combination, included environment, en-
vironmental, pollution, climate, global warming, anesthesia, anesthet-
ics, inhalational anesthetics, volatile anesthetics, implications, health, 
management, waste, impact, life-cycle, and scavenging. The literature 
search criteria were limited to pertinent English-language articles 
from the last 20 years. In total, 16 articles were located. Fourteen 
articles were included for review as 2 of the articles were not 
primary sources.

Anderson et al2 provide an excellent chemical analysis of vola-
tile anesthetics and describe their potential as both GHGs and 
ozone-destroying agents. According to these authors, all volatile 
anesthetics are GHGs, meaning that they have a significant 
atmospheric lifetime and possess infrared absorption bands that 
overlap the outgoing radiation from the Earth’s lower atmosphere. 
GHGs trap the outgoing radiation and cause the Earth’s tem-
perature to rise. In addition to trapping radiation, some but not 
all GHGs also actively deplete the ozone. Ozone is an inorganic 
molecule that is most heavily concentrated in the stratosphere 
and that prevents ultraviolet radiation from reaching the Earth’s 
surface.9 The overall effect of GHGs and ozone-depleting gases 
is to increase the amount of the sun’s radiation that enters and is 
trapped within the Earth’s atmosphere, which is believed to cause 
climate change.

Isoflurane, compared with sevoflurane and desflurane, is the only 
volatile anesthetic capable of destroying stratospheric ozone, 
attributable to the catalyzation that its chlorine ion provides.2 The 
global warming potential (GWP) of volatile anesthetics depends 
on the timeframe in which they are considered. Some agents may 
be strong GHGs and contribute strongly to ozone depletion, but 
their environmental half-life may be very short. Another agent 
may not be destructive to the ozone or as potent a GHG, but may 
stay in the atmosphere for hundreds of years. When assessing 
GWP, time frames of 20, 50, and 100 years are used. The 100-year 
time frame is the most widely used. Desflurane may be the most 
environmentally harmful, because it is used and released into the 
atmosphere in higher quantities. In addition, desflurane has a 
high GWP of over 100 years. Anderson et al2 report that, ulti-
mately, halogenated organic compounds are responsible for 10% 
to 15% of the radiation forces of climate change by GHGs.

Nitrogen oxides, including nitrous oxide (N2O) and nitric oxide, 
are known ozone-depleting substances.10 There has been great 
success in reducing ozone-depleting emissions of chlorofluorocar-
bons, chlorine, and bromine gases through the Montreal Protocol, 
an international treaty aimed at protecting the ozone layer by 
phasing out substances that cause ozone destruction. However, 
this has resulted in an increase in the contribution of N2O to 
GWP; N2O is now second only to methane. Although the prima-
ry anthropogenic source of N2O emissions is fertilizer use, anes-
thesia providers should still be cognizant of the ozone-depleting 

capabilities of N2O use.10 The atmospheric lifetime of N2O emis-
sions, at 114 years, is much longer than that of the other inhaled 
anesthetics, which range from 1 to 14 years.8 In addition, N2O is 
usually used in greater volumes, at concentrations of 40% to 60%, 
in an anesthetic, thus increasing the impact over other anesthetics 
used in lower volumes at concentrations between 1% and 6%.8

In 2010 infrared spectrometry was used to estimate the GWP of 
inhaled anesthetics.11 Looking at the 20-year GWP, desflurane 
and N2O were reported to have significantly greater impacts on 
global warming than isoflurane or sevoflurane. Furthermore, N2O 
was reported to contribute to the destruction of the ozone. These 
authors concluded that to minimize increases to global warming, 
providers should avoid using N2O, use as low fresh gas flows 
(FGFs) as possible, and use either isoflurane or sevoflurane.11

Despite the controversy, the fact that desflurane and N2O have 
significantly greater impacts than other anesthetics holds true. 
Using desflurane for 1 hour at 1 minimum alveolar concentration 
(the alveolar concentration of anesthetic needed to prevent motor 
response in 50% of subjects in response to surgical stimulation) 
equates to the GHG emissions of driving 200 to 400 miles in 
the average automobile.8 The GHG emissions of sevoflurane and 
isoflurane are significantly lower, equaling the GHG emissions of 
driving 8 to 18 miles.8

Sherman et al12 performed a cradle-to-grave analysis of volatile 
anesthetics, meaning they looked at the total environmental foot-
print of the volatile anesthetics. The data incorporated production, 
transport, use, and waste disposal as they relate to contribution 
to GHGs. Overall, the lifecycle phases of the volatile anesthetics 
contribute a relatively insignificant amount to their overall GHG 
emission compared to agent release into the atmosphere during 
use. The authors concluded that desflurane and N2O contribute 
most as GHGs, while isoflurane and sevoflurane contribute much 
less, especially at low flows. They also reference several technolo-
gies in development with the potential to eliminate waste gases 
through capturing and recycling. These technologies include the 
Dynamic Gas Scavenging System (Anesthetic Gas Reclamation 
LLC, Nashville, TN) and the Deltasorb anesthetic collection 
service (Blue-Zone Technologies Ltd, Toronto, Canada).

Berry et al13 described 4 operating rooms that had been equipped 
with reclaiming waste anesthetic gas (WAG) scavenging systems. 
Easy installation and 99% efficiency in eliminating WAG was re-
ported. The authors concluded that recycled product may decrease 
cost and increase the availability of modern volatile anesthetics 
worldwide. While several authors have postulated that WAG 
could be reprocessed and reused using a scavenging system, this 
was the only trial of this technology that could be found in the 
literature.

Jänchen et al14 performed trails of silica zeolite absorbers and 
found them useful in collecting desflurane from the waste gas 
outlet during anesthesia. These authors state that the use of 
charcoal absorbers is partially effective at filtering desflurane 
from WAG, therefore reducing the environmental waste of this 
gas. Zeolite consists of crystalline microporous aluminosilicates. 
Zeolite is much more effective in filtering and desorption of 



Anesthesia eJournal                         www.anesthesiaejournal.com
Volume 5 - No. 1 2017 Page 3

desflurane for collection. In the clinical trial, 62% to 86% of used 
desflurane could be collected with the use of zeolite filters.14 This 
technology holds the potential to eliminate the environmental 
impact of desflurane. With purification, this recovered desflurane 
also holds significant economic savings potential.

Through the use of the GASman computer tool (Med Man Sim-
ulations, Chestnut Hill, MA), Feldman15 was able to simulate the 
various phases of anesthesia, including induction, maintenance, 
and emergence, and the amount of volatile anesthetic used during 
each phase under certain FGFs and volatile anesthetics. He 
found that by reducing flows as safely as conditions allow, it may 
be possible to prevent the release of millions of liters of volatile 
anesthetics into the atmosphere over the course of a provider’s 
lifetime. Key points included turning off flows while intubating, 
titrating flows to patient oxygen needs to reduce use of agents, 
keeping flows low during emergence, and adjusting the vaporizer 
to prevent gases from venting to the atmosphere.

Compared with those of the volatile anesthetics, the GHG effects 
of propofol are minimal. Propofol is, however, not a benign drug 
in reference to its environmental effects. Mankes16 specifically 
looked at propofol wastage and its environmental impacts. He 
found that propofol does not degrade in nature, accumulates in 
body fat, and is ultimately toxic to aquatic life. He recommended 
that propofol wastage—and in turn environmental impact—could 
be reduced by only stocking 20-mL vials.

DISCUSSION
Environmental air pollution and climate change pose threats to 
health, food and water insecurity, increases in infectious disease, 
extreme weather, and population migration.17 Health care provid-
ers should be cognizant of the environmental impact of the care 
they provide. Anesthesia providers must own the entirety of their 
practice, realizing that the impact does not end when the pa-
tient leaves the operating room. Aside from the fact that inhaled 
anesthetics have a negative effect on the ozone layer and global 
warming, if we know that inhaled anesthetics have enough of a 
negative health impact that we must restrict exposure to these 
gases in the operating room, why do we simply vent them into 
our surrounding environment? Given the findings of this litera-
ture review, it appears that all volatile anesthetics contribute, to 
some degree, to global warming. WAG recycling systems have the 
potential to decrease these effects.

Recycling has become an everyday part of our lives outside the 
operating room. With the development of these new technolo-
gies, recycling can now take place in the operating room as well. 
As such, we should advocate for the use of these technologies 
in everyday practice. Recycling of WAG holds the potential to 
eliminate the direct impact these agents have on global warming 
and the ozone layer as well as the potential to reduce the impact 
of their manufacture and transportation.12

Technologies for the collection and recycling of anesthetic waste 
gases include the Dynamic Gas Scavenging System developed by 
Anesthetic Gas Reclamation and implemented and tested with 
the Vanderbilt University Medical Center.18 With this system, 
99% of anesthetic gases are collected and reused. Because the 
vacuum only runs 10% of the time, the system also produces 
energy cost savings. The Deltasorb canister developed by Blue-
Zone Technologies filters self-sterilizing anesthetics that can then 
be sold back to pharmaceutical companies at costs less than the 
costs of producing the original drug.18 Challenges to the reuse of 
WAG include transmission of infectious disease, degradation of 
the quality of the drugs, costs, and existing market pressures from 
anesthetic gas manufacturers.13

Until these systems can be implemented on a widespread basis, 
anesthesia providers must be vigilant in reducing the environmen-
tal impact and costs of anesthesia. Employing techniques to limit 
hazards include low-flow anesthetics, choice of anesthetic agents, 
and proper maintenance of equipment. High FGFs are only nec-
essary when rapid changes in anesthetic depth are necessary (eg, 
induction and emergence). Maintenance, often the longest phase 
of anesthesia, is the ideal time to use low FGFs and to minimize 
anesthetic waste gases. Using an estimated oxygen consumption 
of 5 mL/kg/min for a 70-kg patient, only 350 (mL/min) oxygen, 
plus additional oxygen to compensate for sampling and circuit 
leaks,8 is required to deliver a volatile agent and maintain patient 
oxygenation. To safely implement low FGFs, close monitoring of 
inspired and expired oxygen concentrations is essential. Decreas-
ing inspired concentrations of oxygen indicates underestimation 
of oxygen metabolism and flows should be increased accordingly.8

This review was limited by the relatively small body of litera-
ture on this topic. To further these findings, more research and 
development is required. While there is more literature pertaining 
to the science of global warming and climate change, this remains 
a highly debated and politicized topic. Perhaps a focus on the 
financial benefit of WAG recycling would be the most effective 
avenue for gaining support for these technologies. One alternative 
to the use of volatile anesthetics is the use of total intravenous 
anesthesia. Propofol and other intravenous anesthetics are not 
without environmental impact.

SUMMARY
In 2009, Costello et al declared, “Climate change is the biggest 
global health threat of the 21st century.”19 Given the environ-
mental impacts of the inhaled anesthetics and the development of 
new technologies for WAG reclamation, this technology should 
be widely implemented when clinically available. Given the 
interplay between environment and health, changes in practice 
that reduce or eliminate WAG are worthy of consideration by 
health care providers. The potential cost savings associated with 
reclaimed reusable anesthetic should be investigated further.
 



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Volume 5 - No. 1 2017 Page 4

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