Tonight, we have medical news, a promise of hope for thousands of people who have been through a terrifying event. They are patients who wake up during surgery and feel trapped. But unable to signal... See More
Tonight, we have medical news, a promise of hope for thousands of people who have been through a terrifying event. They are patients who wake up during surgery and feel trapped. But unable to signal the doctors. Again, it happens to about 26,000 americans every year. Abc's chief medical editor dr. Richard besser spokes us somethi something that could mean the nightmare is over. Reporter: Her eyes were closed. Body unable to move. But angela was conscious, on the operating table. It was like a searing pain. I felt like I was being burned. Reporter: An emergency c-section, under general anesthesia. Doctors had no way to know she could feel everything. As awake as I am right now. Reporter: And having surgery? And having surgery. Both with feeling and sensation except I was paralyzed. Reporter: She experienced anesthesia awareness. It's more common in women and runs in families. And for every 1,000 patients who are under general anesthesia, rough ly one or two will be aware. It happens because anesthesia is really more an art than a science. A forest of beeping monitors can't always tell a doctor if a patient is truly unconscious. Inject a little current. Reporter: The new issue of "the atlantic" on stands today reports on what may be a breakthrough -- a new approach that could monitor consciousness itself. You don't want the patient to move, to feel any pain, to have any memory. Reporter: Dr. Giulio tonino's work looks at the brain. His theory? All the electrical signals -- sight, sound, pain, spreading across the brain -- creates consciousness. Think of it as flipping a light switch, with light spilling into all the rooms of your brain. In surgery, anesthesia closes the doors, the lights, the electrical signals can't spread. That's when you are truly unconscious. Tonino's new awareness monitor stimulates the brain with an electrical current to see if it spreads. A truly unconscious brain would have no reaction. A brain conscious during surgery would. You're actually injecting current to the brain and finding out whether the various parts of the brain are talking to each other or not. Reporter: It would mean doctors could finally stop the sort of horror that happened to angela. It's a frightening experience. It really does affect somebody's life a great deal. Reporter: Dr. Richard besser, abc news, new york.
This transcript has been automatically generated and may not be 100% accurate.