- Patients were excluded if they had a body mass index exceeding 30 kg/m2, had a Pittsburgh Sleep Quality Index global scores higher than 6, had an anesthesia time longer than 4 hours, had a history of cardiovascular, neurological, or psychiatric disease, had cervical lymph node metastasis, were treated with sedative and analgesics during the postoperative BIS-Vista monitoring period, were allergic to drugs used in the study, or had been diagnosed with Graves' disease or hyperthyroidism or hypothyroidism.