A total of 120 patients who were admitted to Qinhuangdao First Hospital for and divided into control group (group C ), thoracic paravertebral nerve block combined with full Anesthesia group (group TA), thoracic paravertebral nerve block combined with intraoperative infusion of s-ketamine group ( group TE). 40 cases in each group. Group C received general anesthesia, group TA received 0.375% ropivacaine 20ml thoracic paravertebral nerve block combined with general anesthesia under ultrasound guidance after anesthesia induction, and group TE received s-ketamine anesthesia induction dose of 0.3 mg/kg on the basis of TA group. Anesthesia maintenance dose of 0.2ug/kg/h was pumped to 30min before the end of the operation. The MAP(Mean Artery Pressure) and HR(Heart Rate) of the three groups were recorded before surgery (T1), during the surgery (T2), immediately after surgery (T3). Compare the VAS（Visual analogue scale）in the ten minuses after extubation and one day afte surgery .The cognitive function of the three groups were evaluated by the Mini Mental State Scale (MMSE) on one day before surgery , one day after surgery , and three months after surgery . Compare the incidence of Postoperative Cognitive Disfuntion（ POCD） among the three groups.
To investigate the effect of ultrasound-guided thoracic paravertebral nerve block combined with intraoperative infusion of s-ketamine on postoperative acute pain and cognitive function in patients with thoracoscopic surgery