One minute you’re talking, the next you’re out cold. But what’s actually going on when you are under anesthesia?
We often think of anesthesia as putting us in a deep sleep. But new research suggests it could actually be closer to being in a coma than previously thought. And there’s still lots we don’t know about how these drugs work on the brain, even though thousands of patients undergo a general anesthetic every day.
In a recent study, researchers placed electrodes across the scalps of sedated patients, capturing their brain-wave data. They compared those patterns against data from patients who were awake, asleep or in a coma. The takeaway? The anesthetized patients’ brains produced activity that shared similarities to being unconscious in a coma—as well as deep sleep, REM sleep and patterns unique to anesthesia.
“It’s a very strong perturbation of the system, this kind of profound manipulation of the brain where a person goes from being highly cognitive functioning to basically unconscious,” said Dr. Janna Helfrich , an anesthesiologist and neuroscientist at Yale University School of Medicine and co-author of the research published in the journal Proceedings of the National Academy of Sciences. “The brain didn’t evolve to be anesthetized, so we want to understand how the brain comes back from it.”
Understanding these patterns could help doctors keep patients in a safer, more sleep-like state and reduce postoperative confusion and memory loss, according to Earl Miller , a professor of neuroscience at the Massachusetts Institute of Technology who wasn’t involved in the study.
Anesthesia is considered safe, but there can be problems—some of them serious. Older patients or people with certain health conditions can experience neurocognitive issues after anesthesia, including memory or concentration problems, or postoperative delirium.
Ultimately, gleaning what is happening in the brain could change anesthesia, helping it to be redesigned or personalized to more closely resemble natural sleep rather than a coma-like one, Helfrich said.
“Could we maybe tweak anesthesia a bit more in the direction of sleep, by using different medications or combinations or infusion protocols?” she added. “That would make anesthesia more healthy and better for the brain, and then we could avoid some of the cognitive side effects.”
