Anesthetic Gases Raise Earth's Temperature

A shocking new study revealed that anesthetic gases, of all things, raise Earth's temperature - well, at least a little.

It is well known that carbon emissions from the burning of fossil fuels, automobiles or deforestation all contribute to climate change, but now it appears that the gases used to knock out surgery patients also play a small role. Specifically, concentrations of the anesthetics desflurane, isoflurane and sevoflurane have been rising globally over the last decade, with the compounds detected as far afield as Antarctica.

"Health care in and of itself in the US is one of the worst polluting industries," anesthesiologist Jodi Sherman, from the Yale University School of Medicine, said in a statement. "It generates 8 percent of US greenhouse gases according to one study. Add to this the fact that climate change has been recognized by the World Health Organization as the number one health issue of the 21st century, and it behooves us to do a better job with emissions."

Anesthesia gases, like the infamous greenhouse gas carbon dioxide (CO2), allow the atmosphere to store more energy from the Sun. However, unlike CO2, medical gases are extra potent in their greenhouse gas effects.

For example, 2.2 pounds (1 kg) of desflurane is equivalent to 5,512 pounds (2,500 kg) of CO2 in terms of the amount of greenhouse warming potential, researchers say.

In a new paper published in the journal Geophysical Research Letters, researchers determined global concentrations of the anesthetic gases by collecting samples of air from remote sites in the Northern Hemisphere since 2000, as well as during an expedition in the North Pacific in 2012. They have also been tracking the anesthetics since 2013 in two-hourly measurements from air sampling in Switzerland.

To turn these air samples into their global emissions estimates, the data were combined with a 2-D computer model of atmospheric transport and chemistry.

They found that the concentration of desflurane in 2014 was 0.30 parts per trillion (ppt). Meanwhile, isoflurane, sevoflurane and halothane came in at 0.097 ppt, 0.13 ppt and 0.0092 ppt, respectively.

That doesn't seem like much compared to CO2, which hit 400 parts per million in 2014, and is a billion times more abundant than the most prevalent of these anesthetics.

However, even though they might be small players, anesthesia gas abundances are growing and should not be overlooked, according to researchers.

"What the report fails to note is that a major factor determining the environmental effect is the manner in which the anesthetics are used," noted anesthesiologist Edmond Eger of the University of California at San Francisco. "Many anesthetists deliver sevoflurane or isoflurane in a two - three liters per minute flow but deliver desflurane in a lower flow - 0.5 to one liter per minute."

Though some anesthesiologists would disagree with dropping the use of anesthetic gases such as desflurane, the fact of the matter is that this is a growing matter of concern to many in the health-care industry, and adds yet another factor to the issue of climate change.

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