Although it is rare for surgical patients to become aware of any portion of their surgery while under general anesthesia, in a small subset of these patients such “anesthetic awareness” can cause long-term psychological effects.
A study of surgical patients at LinkopingUniversity in Sweden shows that symptoms of post-traumatic stress from such awareness episodes may be less common than previously thought. The study is published in the January issue of Anesthesiology, the journal of the American Society of Anesthesiologists.
For the study, 2,681 consecutive patients scheduled for general anesthesia between January 2001 and May 2003 were surveyed. Ninety-eight of these patients (3.7 percent) considered themselves to have experienced some awareness during a previous surgery at some time in their lives. Some of these prior surgeries dated back as far as the 1930s.
These 98 patients were interviewed further, and it was determined that four of the cases of possible awareness were actually surgeries performed using regional anesthesia (in which numbing medicine is injected without general anesthesia and the patient is expected to be somewhat aware). 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.
In the remaining cases of likely awareness during general anesthesia, patients were interviewed about their awareness experience and the emotional and psychological effects afterward. Their reported recollections ranged from auditory, tactile and visual awareness (most common) to pain (less common).
Some examples of the patients’ recollections, with procedure and year of surgery, included:
“Saw the nurse upside down. She talked calmly to him.” (Laryngoscopy, 1981)
“Severe short pain.” (Fracture stabilization, 1935)
“Felt intubation and short surgery instrumentation.” (Cholecystectomy, 1974)
“Heard communication between surgeons. Moderate pain from sternotomy.” (Coronary artery bypass grafting, 1997)
Thirty patients (about 65 percent of the group) 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 psychological 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 contains useful information about the ages and health status of the patients, the types of surgeries they had, and to whom they reported their awareness experiences. It is important to note that many of these cases occurred prior to the widespread understanding, in recent years, in the medical community of this phenomenon.
According to lead author Peter Samuelsson, M.D., “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.”
For additional information on this study, go to:
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.anesthesiology.org