Anesthetic gases used in surgical procedures are finding their way into the atmosphere. Photo by Julian Rovagnati/Shutterstock
DUBENDORF, Switzerland, April 7 (UPI) -- A new study suggests the gases commonly used to knock out patients before surgery are accumulating in the atmosphere, and may be contributing to global warming.
Scientists say atmospheric concentrations of common anesthetic gases like desflurane, isoflurane and sevoflurane are on the rise, and have been detected as far away as Antarctica. Relative to other gases, like nitrogen, oxygen and CO2, the levels of anesthetic gases are quite small. But even in tiny doses, these gases pack a powerful punch in terms of their greenhouse effect.
According to the atmospheric chemists responsible for the new research, a single kilogram (2.2 pounds) of desflurane offers the same greenhouse warming potential as 2,500 kilograms (5,512 pounds) of carbon dioxide.
"On a kilogram-per-kilogram basis, it's so much more potent," lead study author Martin Vollmer, a researcher at the Federal Laboratories for Materials Science and Technology in Dubendorf, said of anesthetic gases.
To estimate the total levels of anesthetic gases in the atmosphere, researchers relied on a series of air samples collected throughout the Northern Hemisphere since 2000. Using a computer model, scientists used these small samples to extrapolate global concentrations.
Their analysis -- detailed in a recent issue of Geophysical Research Letters -- suggests desflurane measures 0.30 parts per trillion (ppt). Slightly less abundant are isoflurane, sevoflurane and halothane, which measured 0.097 ppt, 0.13 ppt and 0.0092 ppt, respectively.
Their methods offer a new bottom-up strategy for estimating the total tonnage of atmospheric gases. The method can both complement and be compared to top-down estimates, which use measurements like the amount of gas sold, as well as the percentage escaped during surgical use and the metabolic process, to predict atmospheric concentrations.
While anesthetic gases remain minor contributors to global warming, curbing the greenhouse warming requires all industries to cut back emissions.
"Health care in and of itself in the U.S. is one of the worst polluting industries," said Jodi Sherman, an anesthesiologist at the Yale University School of Medicine who reviewed the GRL paper. "It generates 8 percent of U.S. 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."
Doing a better job with a emissions might mean subbing in a less potent substance for desflurane.
"There's nothing unique about desflurane that we can't do with other drugs," Sherman said. "Desflurane we could live without, and every little bit makes a difference."