Waking Up During Surgery Not Uncommon

One out of 1000 people wake up during surgery, and Boston researchers are trying to change that.


Not the time you want to wake up. Photo via Shutterstock

Waking up during surgery sounds like an irrational fear, but the scary part is it’s not that uncommon. In fact, experts estimate that it happens to one out of every 1,000 patients who have an operation—so often that it has a name: anesthesia awareness. Yikes. But before you swear off medical care forever, know that Boston researchers are getting closer to lowering that statistic.

A team of researchers from Boston University, MIT, and Massachusetts General Hospital have, for the first time, mapped the specific electrical brain activity that goes on when a patient loses and regains consciousness under anesthesia. The researchers observed the EEGs (short for electroencephalography, a measure of brain activity) of volunteers given general anesthesia and measured their brain signals as dosages were increased and decreased. What they found was surprising. The brain activity did not drop off when patients lost consciousness, as conventional wisdom previously suggested—instead, a new set of brain rhythms emerged. A report from Boston University quotes the paper’s co-author Nancy Kopell, a professor at the university and head of the Center for Computational Neuroscience and Neural Technology:

“One reason why there’s a loss of consciousness is that there’s a change in the flow of signals within the brain,” says Kopell. She and ShiNung Ching, a postdoctoral associate, created computer models showing that the anesthetic leads to abnormal synchrony among brain regions, which impedes normal processing; they think the inability of regions to signal one another in normal ways is a critical reason for the loss of consciousness. The researchers also discovered specific sets of EEG signals for deep anesthesia, as opposed to entering or emerging from unconsciousness.

What these results, which were published in the online journal PNAS, mean for the average person is that it’s becoming far easier for doctors to determine when a patient is fully unconscious under anesthesia and when they’re close to waking up. So much so that MGH’s Patrick Purdon, who served as the study’s lead author, is working to build a sensor that will alert doctors to when their patients are close to regaining consciousness so that it won’t happen in the middle of surgery, an experience that, in addition to being physically painful, can leave patients psychologically scarred. The BU report quotes Purdon:

“We are hoping that soon we’ll have the problem solved and anesthesia awareness will be a thing of the past,” he says.