A Case of Prolonged Postoperative Somnolence: Possible Anticholinergic Syndrome Caused by Drug Interactions

Abstract

We report the case of a 50-year-old woman who experienced delayed awakening after laparoscopic cholecystectomy under general anesthesia mainly with continuous propofol infusion. Atropine (0.5 mg) was administered because of sudden bradycardia (42-43 bpm) developing in the postanesthesia room. Consciousness was slightly recovered by intravenous administration of flumazenil, even though we had not used benzodiazepine during anesthesia. Anticholinergic syndrome caused by interactions among atropine, propofol, and an antihistamine agent taken by the patient for a prolonged period before surgery, as revealed by her medical history, was highly suspected. Unfortunately, physostigmine was unavailable to reverse the symptoms and facilitate a definitive diagnosis. She was transferred to the intensive care unit for further observation, where she recovered her consciousness and was fully alert gradually with stable vital signs and returned muscle power of four limbs 12 h after surgery. The symptom of prolonged postoperative somnolence suggested drug involvement once other neurological deficits were ruled out, the prime suspicion being anticholinergic syndrome. This case report emphasizes the importance of obtaining a complete medical history, including daily medications and considering adverse drugs interactions in order to avoid or ensure proper management of this unusual adverse effect.