Protocol
Patients were treated without premedication. Throughout the perioperative period, electrocardiogram, pulse oxygen saturation, invasive arterial pressure and end-tidal concentrations of carbon dioxide monitoring were necessary. All of patients underwent the operation under total intravenous general anesthesia. Anesthesia was induced with oxycodone (0.2–0.3 mg/kg), propofol (1.0–1.5 mg/kg) and rocuronium (0.9 mg/kg). Intermittent positive pressure ventilation was used after tracheal intubation, with tidal volume of 6–8 ml/kg, respiratory frequency of 10–12 times/min, inspiratory/expiratory ratio of 1:2, PEEP 3–5 cmHPatients who developed POD were given nonpharmacological treatment. If patients could not cooperate with non-drug therapy, haloperidol was given intravenously. Mildly excited patients were given 0.25–0.5 mg, and severely excited patients were given 0.5–1.0 mg. If patients’ symptoms were not relieved, DEX 1ug/kg loading dose was pumped for 10–15 min, and then, 0.25–0.5 ug/kg.h dose was pumped to treat POD.