By JR on Tuesday, April 21, 2015
Anaesthetic is WARMING the planet: Gases used to knock out patients during surgery are contributing to climate change (?)
We're used to being nagged about gas concentrations in parts per million but now we are being nagged about gas concentrations in parts per trillion! We didn't even get to stop on parts per billion. And the idea that the anaesthetic gases are much "stronger" in their effect than CO2 ignores completely that the magnitude of CO2 effects is very unsettled (The "climate sensitivity" debate). There is reason to believe that the effect of CO2 is real but negligible. The same may be true of the anaesthetic gases. Theories take you only so far and can be too simplistic. Certainly in the last 18 years the theoretical effect of the trace gases has not accorded with reality
Anaesthetic gases used to send patients to sleep during surgery are accumulating in the Earth's atmosphere where they are contributing to climate change.
Scientists say they have detected the gases used in anaesthetic as far afield as Antarctica and concentrations have been rising globally in the past decade.
The gases - desflurane, isoflurane and sevoflurane - are potent greenhouse gases that have 2,500 times the impact on global warming compared to carbon dioxide.
Dr Martin Vollmer, who led the study at the Swiss Federal Laboratories for Material Science and Technology in Dubendorf, Switzerland, said the anaesthetic gases were capable of storing far more energy from the sun than carbon dioxide.
He said: 'On a kilogram-per-kilogram basis, it's so much more potent. 'Modern halogenated inhalation anesthetics undergo little metabolisation during clinical application and evaporate almost completely to the atmosphere.'
The researchers, whose work is published in the journal Geophysical Research Letters, found that concentrations of desflurane reached 0.30 parts per trillion in 2014.
Isoflurane, sevoflurane and halothane have reached 0.097, 0.13 and 0.0092 parts per trillion in the atmosphere respectively.
By comparison, carbon dioxide gas currently makes up 400 parts per million in the atmosphere.
However, one kilogram (2.2lbs) of desflurane produces the same greenhouse effect as 2,500 kg (5,512lbs) of carbon dioxide.
The researchers estimate that anaesthetic gas emissions currently combine to produce the equivalent effect in the atmosphere of 3.1 million tonnes of carbon dioxide.
The research team did not examine the impact of nitrous oxide, another major component of anaesthetic, as it is released by many other sources.
The researchers have been taking air samples from remote sites around the Northern Hemisphere since 2000 while they have also obtained air samples in the North Pacific and the South Shetland Islands in Antarctic.
The team also used two hourly measurements at a high altitude observatory at Jungfraujoch, Switzerland since 2013 to track anaesthetic gases. They then used computer modelling to produce global estimates for the concentrations of these gases.
However, Edmond Eger, an anaethesiologist at the University of California San Francisco, said: 'What the report fails to note is that a major factor determining the environmental effect is the manner in which the anesthetics are used.
'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. 'Some believe that desflurane has clinical advantages that argue for its continued use.'