The Effect on the Older's Cognition of Dual-loop Target Controlled Infusion Guided by Narcotrend Index

To investigate the effect on older's cognition of the application of closed target-controlled infusion(TCI) of propofol and remifentanil guided by Narcotrend index .

Two hundreds of patients scheduled for surgery under general anesthesia were randomly divided into two groups:closed-loop (group A,n=100) and open-loop group(group B,n=100).The procedure during induction of anesthesia was same in two groups.In group A,if Narcotrend index(NI) fall down to 46 and keep more than 30 seconds,propofol and remifentanil were intravenously infused as feedback automatically to achieve the target NI of 26-46.However,the NI in group B was controlled manually.Taking an exam of MMSE before and after the surgery which measures if the older's cognition changed. Furthermore.we will measure the levels of protein S100beta and NSE.

Inclusion Criteria:

1. ASA Ⅰ ~ Ⅱ women undergoing Laparoscopic surgery.
2. Written informed consent from the patient or the relatives of the participating patient.
3. BMI:18.0～25 kg/m2

Exclusion Criteria:

1. Mental illness can not match
2. epidural anesthesia contraindicated
3. People who have Slow-type arrhythmias
4. Chronic renal failure
5. Alcohol or drug abuse
6. Already taking gabapentin, pregabalin, benzodiazepin or antidepression dru