When you're in enough pain to need a substantial operation, environmental consequences may be the last thing on your mind, but anesthetics do a surprising amount of damage to the climate. Fortunately, there are eco-friendly options that, as they say, won't hurt a bit.
Anesthetics have made an immeasurable contribution to human wellbeing and hardly anyone is suggesting we abandon them. However, there is plenty of debate about where the line should be drawn between the conditions that need general anesthetic and those that can be done under local. General anesthetics often induce nausea and can be associated with slower recovery or even death.
On top of these familiar considerations, a team led by Dr Christopher Wu want doctors and patients to factor in the environmental reasons to prefer local where possible.
Although there are accounts of drugs being used to make people lose consciousness dating back thousands of years, until the 19th Century surgery was so painful many people chose death. Nitrous oxide (laughing gas) changed that and is still in use today, now in combination with volatile halogenated gases. Unfortunately, molecule-for-molecule nitrous oxide heats the planet 2-300 times more than carbon dioxide, as well as damaging the ozone layer. The volatile halogenated gas desflurane has an estimated 3,700 times CO2's heating effect for equal weight.
Most of these gases are expelled from the patient's lungs eventually and escape into the atmosphere. In Regional Anesthesia and Pain Medicine, Wu calculates a typical operation releases gasses with the same warming effect as burning almost 2 kilograms (4 pounds) of coal.
The more than a million hip and knee arthroplasties performed in the United States each year are the equivalent of driving an average car around the planet 300 times. If there were no other painless ways to perform these surgeries, this might be marked down as another of those things we need to find a way to offset. However, Wu argues most of these operations can be done just as well under local anesthetic, avoiding the environmental damage.
Across America, 75 percent of hip and knee arthroplasties are done under general anesthetic alone, and another 14 percent use both local and general. At New York's Hospital for Special Surgery, where Wu works, the figure is just 4 percent, and he claims the outcomes are usually better for the patient as well as the planet.
Compared to removing fossil fuels from electricity generation or saving the rainforests, shifting from general to local anesthetics may make a minor contribution to the fight for a habitable planet. For individual doctors, however, it could be among the most important things they could do, and if Wu's claim is right, it's one that is particularly painless.