Most people who go under general anesthesia for surgery don't perceive or remember their operations. But a few do -- and accounts of the experience are unsettling.
In search of the best ways to prevent unintended intraoperative awareness, as it is called, a team of researchers recently conducted a randomized trial, involving 6,041 patients at high risk for the complication, to determine whether monitoring electrical activity in the brain during surgery was a more effective tool for keeping patients unconscious than a standard and less expensive monitoring method that measures the concentration of anesthesia in exhaled breath.
To their surprise, it was not. In fact, according to the team's study, which was published Wednesday in the New England Journal of Medicine, seven out of the nine patients who had "definite awareness" of their surgeries -- and 12 of the 18 who had "possible awareness" -- were in the group who received the electroencephalogram-assisted monitoring.
As many as 70% of the 20,000 to 40,000 people in the U.S. who have unintended intraoperative awareness go on to develop post-traumatic stress syndrome, the team noted in their paper. Considering the personal accounts appended to the study, it's not hard to see why.
One patient undergoing heart surgery, a 72-year-old man, reported that he "could hear knives (like a buzzing sound.) I could hear and feel the saw cutting into me, but I was not in pain. I felt warm water or blood running inside me...I was very afraid. I felt like my wife, my kids, and everyone had abandoned me."
A 32-year-old woman having an adrenal gland removed remembered "hearing events of the surgery, having the feeling that she couldn't breathe, feeling the sensation of the breathing tube, feeling anxiety and stress just briefly. She felt panic."
One man recalled hearing "clinking sounds, like someone was sorting cutlery." Another man had "a visual memory of extremely bright lights, several people around, and black and white images of his children." Another "felt like I was drowning...it seemed like a long time."
On the upside, a 60-year-old woman having gastric bypass surgery "felt both happiness and helplessness. She felt safe."
The study was conducted by researchers from Washington University, the University of Chicago, the University of Manitoba in Canada and the University of Michigan.