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Awake During Surgery: How Rare?

Less Than 1% of Patients Experience Anesthesia Awareness Under General Anesthesia
By
WebMD Health News
Reviewed by Louise Chang, MD

Nov. 28, 2007 -- Anesthesiologists today reported that "anesthesia awareness" -- being conscious during surgery -- affects less than 1% of U.S. patients given general anesthesia.

Doctors addressed the topic in a live webcast from New York, spurred by Friday's release of the movie Awake, a fictional thriller based on anesthesia awareness, also called unintended intraoperative awareness.

There have been "a lot of different studies" trying to pinpoint the incidence of anesthesia awareness, Marc Bloom, MD, PhD, of New York University Medical Center, told reporters.

Several studies put the incidence of anesthesia awareness at 0.1% of all general anesthesia patients. That works out to be about 21,000 of the 21 million people in the U.S. who get general anesthesia in a typical year.

But if high-risk patients aren't included, the numbers drop to about one in 40,000 patients, Bloom says.

"But let's get out of this box of how often it occurs. Really, one case is too many," says Orin Guidry, MD, of the Medical University of South Carolina.

"As anesthesiologists, we are not going to stop until we can get that risk down to zero," says Guidry, who is a past president of the American Society of Anesthesiologists (ASA). 

(Do you have a fear of waking during surgery? Share your stories on the Health Cafe message board.)

Avoiding Anesthesia Awareness

Anesthesia experts urge patients and doctors to talk about anesthesia before surgery, including a frank discussion about side effects, risks, and past experiences with anesthesia.

Some patients -- including people getting heart surgery, emergency surgery, or C-sections -- may be more likely to experience anesthesia awareness. That's because doctors may need to use a lighter dose of anesthetic to keep the patient (or baby, in the case of C-section) stable.

Patients may remember procedures that involve local anesthesia, but that's not anesthesia awareness, the panelists note.

The use of brain function monitors during surgery can cut the chance of a patient experiencing anesthesia awareness, according to Bloom, Guidry, and colleagues.

But the doctors warn that those devices don't rule out all possibility of anesthesia awareness.

They describe a fine line between too little anesthesia, which may lead to anesthesia awareness, and too much anesthesia, which may cause side effects including nausea and vomiting after surgery.

"We are still in a situation where we have to use all of our senses and all of our knowledge," Bloom says. "At this point, there is no way to flip a switch and let the monitor tell us how much [anesthesia] to give."

The webcast was sponsored by Stryker, which makes a brain function monitor.

Anesthesia Awareness Advocate

All of the doctors who took part in the webcast say they don't know of any of their patients who experienced anesthesia awareness.

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