Waking up in the middle of an operation sounds like something out of a horror movie, but new research has revealed that it could happen a lot easier than you probably thought.
New research published in the journal Anesthesiology suggests that humans are not fully unconscious when under general anesthetic. Instead, it is similar to a sleeping state.
A team of researchers at the University of Turku in Finland analyzed changes to the brains of 47 healthy volunteers when under general anesthetic.
The patients were either given the sedative dexmedetomidine or the general anesthetic propofol.
It was discovered that something like a loud noise or being briefly shaken could be enough to bring people back to consciousness, with 42 percent of participants able to be awakened.
All of this took place after the patient reached either loss of responsiveness or loss of consciousness and while the drugs were still being administered.
“Nearly all participants reported dreamlike experiences that sometimes mixed with the reality,” study author and professor of psychology Antti Revonsuo said in a statement.
“The state of consciousness induced by anesthetics can be similar to natural sleep. While sleeping, people dream and the brain observes the occurrences and stimuli in their environment subconsciously.”
Some of the participants were even able to recall parts of the operation, though their memories were hazy.
The participants were also played recordings of sentences that ended unexpectedly, to test how their brains would react to the unusual phrases.
“The night sky was filled with shimmering tomatoes,” was one of the lines used.
When a person is awake, the unexpected word would usually cause a spike in brain waves as the mind tries to figure out the meaning of the word.
However, when the patients were under anesthesia, the brain was unable to differentiate between the normal and unusual words and there was a “significant” response to the whole sentence. This means that the brain became more alert trying to figure out what all of the words meant.
After the patients woke up, though, they could not remember the sentences that were played to them.
There were even more noticeable reactions when the participants were played unpleasant noises, with their brains reacting faster to those particular sounds after they woke up than others they hadn’t heard.
“In other words, the brain can process sounds and words even though the subject did not recall it afterwards,” said adjunct professor of pharmacology and anesthesiologist Harry Scheinin.
“Against common belief, anesthesia does not require a full loss of consciousness, as it’s sufficient to just disconnect the patient from the environment.”