Awake During Surgery: How Rare?
Less Than 1% of Patients Experience Anesthesia Awareness Under General Anesthesia
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
"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).
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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
But the doctors warn that those devices don't rule out all possibility of
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
The webcast was sponsored by Stryker, which makes a brain function
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.