Implications of Explicit, Intraoperative Recall

Limited information is available on the postoperative consequences of intraoperative recall. Blacher^[74] described a traumatic post-cardiac surgery neurosis involving anxiety and irritability, repeated nightmares, preoccupation with death, and a reluctance to discuss these symptoms. He attributed this postoperative state to patients' being awake and paralyzed during open heart surgery. These patients responded favorably to assurances that their postoperative difficulties may have been caused by awareness during surgery.

Ghoneim and Block^[75] reviewed the consequences of intraoperative or explicit recall. The two most frequent complaints were an ability to hear events during surgery and the sensation of weakness/paralysis, with some patients experiencing pain. Patients particularly recall conversations that are of a negative nature concerning themselves or their medical condition. The most frequently reported postoperative effects were sleep disturbances, dreams, nightmares, flashbacks, and daytime anxiety. For many patients, the experience of awareness may not leave prolonged aftereffects; in some, however, a post-traumatic stress disorder marked by repetitive nightmares, anxiety, irritability, a preoccupation with death, and a concern with

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Lennmarken and associates^[76] provided follow-up information on the intraoperative awareness patients prospectively identified by Sandin and colleagues.^[49] Nine of the 18 patients with documented explicit recall of surgery were interviewed 2 years later. Four of the nine were still severely disabled because of psychiatric/psychological sequelae and fulfilled the clinical criteria for post-traumatic stress disorder. All these victims had been offered and received therapy for the intraoperative awareness immediately after it was identified. This study suggests a need for longer-term follow-up of patients who experience awareness during surgery.

Ghoneim has summarized the large body of investigation attempting to understand the role of implicit memory for events during anesthesia.^[77] Implicit memory while under anesthesia refers to changes in performance or behavior that can be produced by previous experience or tests that do not require any intentional or conscious recall of these experiences. These investigations have studied the indirect memory of patients and responses to behavioral and therapeutic suggestions made under anesthesia. At very light levels of anesthesia, it can be demonstrated that memory and implicit recall can occur, whereas deeper levels of anesthesia eliminate the ability to detect any implicit recall or memory. There is no good, consistent evidence that verbal therapeutic suggestions given during anesthesia, which would involve implicit memory, can meaningfully alter postoperative performance (i.e., pain management, prevention of side effects). Ghoneim concludes that implicit memory after anesthesia has proved to be an elusive phenomenon.