General anesthetic can damage your brain: study
• Surgical operations involving general anesthetic may damage mental ability by starving the brain of oxygen, researchers fear, after conducting tests on climbers as they scaled Mount Everest.
Up to one-fifth of people develop hypoxia, or oxygen deficiency, after surgery, which can lead to symptoms such as wheezing, confusion, high blood pressure and even heart failure and death.
But research from City University of London and University College London suggests the condition can also have a significant impact on brain function, with the effects lasting for at least 11 days after oxygen deprivation.
The study, which monitored 198 climbers who scaled Everest, where there is only one-third the oxygen at sea level, found significant cognitive decline after the teams descended. In particular, speech and language, learning, planning, focusing and organizing were severely affected, with performance falling by nearly 20 per cent on tests taken before and after the ascent. The effects were still present 11 days later.
Researchers believe the results may partially explain why far more climbers die coming down from the Everest than they do going up.
Asked whether the same impact might be seen after surgery, study leader Prof. Stanton Newman, dean of the School of Health Sciences at City, said: “Absolutely. What we found is that there was a clear relationship between levels of hypoxia and brain function which has not been established before.
“It was possible to group people into three groups, some of whom had mild effects, and some whom it was significant. We noticed that it was worse for older people.
“We know that a number of people who go back to work after surgery and find that they have cognitive problems but it was unclear what was causing it.
“We also noticed that the declines happened even when people were given oxygen and their oxygen levels returned to normal.”
Hypoxia can also be caused by emphysema, bronchitis and pneumonia. The research was published in the journal PLOS One.