Device Cuts Risk of Awareness During Surgery

Monitor Helps Ensure Deep Sleep While Under Anesthesia

From the WebMD Archives

May 27, 2004 - It's a real-life nightmare for about two in every 1,000 surgery patients.

Doctors simply call it "awareness during surgery." For patients, it is the trauma of knowing what's happing as doctors cut into their body, but being helpless to do anything about it.

Even in dry medical terms, it sounds horrible as described in the May 29 issue of The Lancet, by Paul. S. Myles, MD, MPH, of The Alfred Hospital, Melbourne, Australia, and colleagues.

"Affected patients report perception of paralysis, conversations, and surgical manipulations, accompanied by feelings of helplessness, fear, and pain," they write. "Some patients have rated it as their worst hospital experience. Posttraumatic stress disorder can develop in those who are severely affected."

Myles and colleagues now report that an electronic monitoring device can cut the risk of awareness during surgery.

In a trial sponsored by the manufacturer of the device, they find that the BIS monitor can cut this risk by more than 80%.

Patients at High Risk of Awareness During Surgery

Some patients are at particularly high risk of awareness during surgery:

  • Women undergoing C-sections
  • High-risk, heart surgery patients
  • Trauma patients getting emergency surgery

Myles and colleagues enrolled about 2,500 of these high-risk patients in a clinical trial. Half got surgery with the BIS monitor and half didn't.

Eleven patients in the routine care group -- but only two patients in the BIS monitoring group -- reported awareness during surgery.

The BIS monitor is already approved for use in the U.S. Myles and colleagues estimate that it adds about $16 to the cost of an operation.

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SOURCES: Myles, P.S.The Lancet, May 29, 2004; vol 363: pp 1757-1763. Lennmarken, C. and Sandin, R.The Lancet, May 29, 2004; vol 363: pp 1747-1748.
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