No Long-Term Psychologic Effects of "Anesthetic Awareness”

A new study shows that symptoms of post-traumatic stress due to anesthetic awareness episodes of patients undergoing surgery may be less common than previously thought.

Researchers at Linkoping University (Sweden) surveyed 2,681 consecutive patients who were scheduled for general anesthesia between January 2001 and May 2003. Ninety-eight of these patients (3.7%) considered themselves to have experienced some awareness during a previous surgery at some time in their lives, dating back as far as the 1930s. Of these 98 patients, it was determined that four of the cases were actually surgeries performed using regional anesthesia, and another 29 cases were found to be preoperative nightmares, memories before or after surgery, and other recollections that could not qualify as true awareness under general anesthesia.

Of the remaining patients, 30 (about 65%) stated they had had an acute emotional reaction to their awareness. Eight patients had a delayed understanding that they had been aware for some portion of the surgery. About two-thirds of the group reported no lasting psychologic effects; the remaining third experienced nightmares, anxiety, or flashbacks, although some lasted only a few days or weeks. Only one person had symptoms indicative of post-traumatic stress disorder. For many patients, going on to have future surgeries with completely successful anesthesia helped them to recover from their anxiety caused by the older surgery. The study was published in the January 2007 issue of Anesthesiology.

"We hope that knowledge of awareness has already spread among health care professionals, and this study should not be interpreted as dismissing the significance of this complication,” said lead author Peter Samuelsson, M.D.

In 2005, the American Society of Anesthesiologists approved recommendations issued in a practice advisory to assist decision-making for patient care with the goal of reducing anesthetic awareness. These recommendations were summarized in four major areas: preoperative evaluation of the patient's risk for awareness, use of equipment checklists, monitoring depth of anesthesia, and drug selection. The advisory also stated that patients should be monitored with clinical techniques and conventional monitors such as electrocardiograms (ECGs), vital signs, gas analyzers, and brain function monitors.



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