Effects Of The Melatonin On The Early Postoperative Cognitive Dysfunction In The Elderly General Anesthesia

Objective:To study the influence of the serum melatonin on the early postoperative cognitive dysfunction(POCD) in the elderly patients under general anesthesia.Methods:32 abdominal surgery patients with ASA Ⅰ～Ⅱ were undergone general anesthesia. All patients were more than 65 years old. The score of cognitive function were estimated by mini-mental state examination (MMSE) at the day of preperation, the 1st and 3rd days of postoperation.According to the score, the patients were divided into POCD and NPOCD groups. The induction of anesthesia was induced by midazolam (0.05-0. lmg/kg), cisatracurium besylate (0.15 mg/kg), fentanyl (2-4μg/kg) and etomidate (0.2-3mg/kg). The maintenance of anesthesia was used the intravenous pump and continuous injected the propofol 4-8 mg/kg/h and remifentanil 6～10μg/kg/h. According to the need of anesthesia and surgery, the propofol or remifentanil infusion dosage was adjusted.To maintain the muscle relaxation, the cisatracurium besylate was intermittent injected in to the venous.The venous blood was taken at before induction of anesthesia (T1) and postoperation (T2). The serum melatonin concentration was measured by ELISA.Result:11 patients (34.38%) was occurred the POCD on the 1st day postoperation. The serum melatonin levels were 72.571±4.405 and 44.829± 4.014 at the preoperative and postoperative in the POCD group, and were 72.499±5.890 and 53.554±6.675 at the preoperative and postoperative in the NPOCD group.Compared with the preoperative period, the melatonin levels was decreased on the postoperative period in the two groups (all P< 0.01), but the melatonin levels was more significantly decreased in POCD group than that the NPOCD group (P<0.01).Conclusions:1. The melatonin levels was decreased after general anesthesia operation in elderly patients.2.The occurrence of POCD may be related with the decreased melatonin content.