"Awake," a new movie starring Jessica Alba and Hayden Christensen opening this Friday, promises to do for surgery what Jaws did for swimming in the ocean.

The film, which opens Nov. 30, tells the story of a heart transplant patient whose anesthesia fails, leaving him fully conscious but physically paralyzed. While he's awake on the operating table, he hears the surgeons' plans to deliberately kill him.

Text within the movie trailer is startling: "Every year, 21 million people are put under anesthesia... 1 in 700 remain awake", while the synopsis on the movie's official website claims that "anesthesia awareness" is "a common occurrence."

Dr. Stephen Brown says that couldn't be further from the truth.

Brown, the Chair of Ontario Medical Association's Section on Anesthesia and the chief of the department of anesthesia at North York General Hospital, says the movie is doing what Hollywood does best: sensationalizing.

"Anesthesia awareness" certainly happens, he says, but it is hardly common. He believes that in Canada, the incidence is probably closer to 1 in 1,000 to 1 in 3,000 cases. And among those cases is a wide array of experiences.

"Anesthesia awareness is really a spectrum of things that can happen in the operating room," he explained to CTV.ca in a phone interview.

The most common experience is a patient waking up briefly and hearing elements of conversation, or remembering after the surgery a song playing in the background in the operating theatre.

"Those vague sensations of awareness that are not particularly unpleasant, where they are aware of something they shouldn't have been, that's the vast majority of these awareness cases," Brown says.

The terrifying experience that Christensen's character goes through -- in which he is fully awake, feeling absolutely everything but completely paralyzed -- "if we were to estimate the incidence of that, we're probably talking 1 in 50,000 or 1 in 100,000. It's much more rare than the movie suggests," Brown claims.

Carol Weihrer, the founder and president of the Anesthesia Awareness Campaign, doesn't believe those numbers. She says that about 100 to 200 cases of anesthesia awareness are reported in the United States every day and that many more cases go unreported.

Weihrer lived through an "Awake" experience" herself in 1998, she told CTV Newsnet.

"While my right eye was being surgically removed, I received no anesthesia but plenty of paralytic and I was totally unable to move or communicate in any way but absolutely aware of what was going on," she recalled.

"When you have a paralytic you are literally in a body that will not do anything. You can't scream, you can't wiggle, you can't move... I was screaming inside my own head and literally thought I was dying."

She says, like so many other victims of anesthesia awareness, she now deals with post-traumatic stress disorder.

"I personally have not slept in a bed since Jan. 24, 1998. I can't lie flat. I have startle responses that are exaggerated. I don't like to be in crowds. I don't like to be in noisy places. I have panic attacks, triggers, nightmares, sleep disorders, and don't go into REM sleep. I sleep about an hour and 15 minutes at a time."

Brown explains that there are situations in which the risks for anesthetic awareness are higher. Emergency surgeries are one such situation. A car accident victim, for example, who has lost a lot of blood, is an unstable patient. His blood pressure and heart rate are already dropping so he cannot tolerate full doses of anesthetics, Brown says.

"So you may have to lighten up the anesthetic for those patients, and so you may have an increased incidence of anesthetic awareness in such patients," he explains.

"Our job is to the best we can with the situation."

Other cases of awareness can happen when the anesthesiologist mistakenly uses the wrong drug or isn't aware, for example, that the patient is a heroin addict who has therefore adapted to handle large doses of opiates. Other problems can be blamed on machinery.

"Some brands of inhaled anesthetics have alarms that tell you when you are running low, but others don't," says Brown. "So it's possible you could run the canister dry during one operation and then the next guy could come in and not notice. So yes, it could happen -- and I'm sure it has happened -- but it's difficult for me to estimate how often that has happened."

Weihrer says the number of cases of anesthesia awareness could be greatly reduced if brain activity monitor machines, called Bi-Spectral Index (BIS) monitors, were used in all surgeries involving general anesthesia.

The American Society of Anesthesiologists does not endorse that view, nor does Brown.

"BIS monitors are an imperfect tool. They can be helpful in high-risk surgeries but it's not standard-of-care for all surgeries," he says. "They're expensive to run and the technology hasn't been proven to reduce awareness in routine surgeries."

"I think the American Society of Anesthesiologists has taken the appropriate stance, which is to base their decision on evidence."

As for the movie, "Awake," Brown hasn't seen it yet. But so far, he's not pleased with the message it's sending to patients considering surgery.

"They're definitely sensationalizing the phenomenon of anesthesia awareness for theatrical benefit," he says of the film's writers.

"And hey, it might be a very entertaining movie. I don't know. But I don't think it's doing a service to the public to scare them unnecessarily."