Anaesthetic gases contributing to global warming, new research suggests

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Researchers have suggested through a new research that anaesthetic gases are accumulating in the Earth’s atmosphere and are playing a small role in global warming.

Over the past decade, concentrations of the anaesthetics desflurane, isoflurane and sevoflurane have been rising globally and the study has detected the compounds as far a field as Antarctica.

Like the well-known climate warmer carbon dioxide, anaesthesia gases allow the atmosphere to store more energy from the Sun, the researchers noted.

But unlike carbon dioxide, the medical gases are extra potent in their greenhouse-gas effects.

“One kilogram of desflurane, for instance, is equivalent to 2,500 kilograms of carbon dioxide in terms of the amount of greenhouse warming potential,” said lead researcher Martin Vollmer, atmospheric chemist at the Swiss Federal Laboratories for Materials Science and Technology in Dubendorf, Switzerland.

“On a kilogram-per-kilogram basis, it is so much more potent” than carbon dioxide, he said.

The researchers reported the 2014 atmospheric concentration of desflurane as 0.30 parts per trillion (ppt).

Isoflurane, sevoflurane and halothane came in at 0.097 ppt, 0.13 ppt and 0.0092 ppt, respectively.

The team did not include the common anaesthesia nitrous oxide in the study because it has many sources other than anaesthetics.

The researchers obtained their numbers by collecting samples of air from remote sites in the Northern Hemisphere since 2000, as well as aboard the icebreaker research vessel Araon during an expedition in the North Pacific in 2012 and at the South Korea Antarctic station King Sejong in the South Shetland Islands.

They have also been tracking the anesthetics since 2013 in two-hourly measurements at a high-altitude observatory at Jungfraujoch, Switzerland, and from ongoing air sampling from a rooftop in a suburb of Zurich, Switzerland.

To turn these air samples into their global emissions estimates, the data were combined with a two-dimensional computer model of atmospheric transport and chemistry. The results are the first so-called top-down estimates–based on actual atmospheric measurements–of how many metrics tons of each anesthetic were released into the atmosphere in 2014.

That can now be compared to “bottom-up” estimates by other researchers, which estimate atmospheric concentrations based on factors such as how much of each gas is sold annually, how much typically escapes through operating room vents and how much is not metabolized by patients.

Although anesthetics are small players in overall human-generated greenhouse emissions, they are a growing matter of concern to many in the health-care industry. Anesthesia gas abundances are growing and should not be overlooked, said Yale University School of Medicine anesthesiologist Jodi Sherman, a reviewer of the GRL paper.

“There is nothing unique about desflurane that we can not do with other drugs,” Sherman noted.

She argued that it is possible to live without Desflurane.

The study appeared online in the journal Geophysical Research Letters.