An unexpected increase of entropy in a sleepwalking disorder patient during propofol and remifentanil anesthesia: a case report

We report a case of increased values of entropy parameters Response Entropy (RE) and State Entropy (SE) during intravenous general anesthesia in a sleepwalking patient. An ASA class II, 64-year-old woman with stress incontinence underwent mid-urethral sling surgery. Prior to surgery, the patient had been administered paroxetine, valproic acid and clonazepam for the treatment of sleepwalking disorder. After 10 min of target-controlled infusion of propofol and remifentanil, entropy values increased up to 94 (RE) and 88 (SE) for 10 min. The target effect-site concentrations of anesthetics increased from 4 to 7 µg/ml propofol and 4 ng/ml remifentanil, at which point values fell back to adequate anesthesia levels. Episodes of recall or of explicit memories did not occur during the anesthesia. In conclusion, sleepwalking patients with long-term use medications may need increment of anesthetic dose caused by the anesthetic drug metabolism activation or impairment or immaturity of inhibitory circuits in brain.