The Effect of Continuous Femoral Nerve Block With Modulation of Depth of Anesthesia on Prognosis of Patients Receiving Total Knee Arthroplasty

The interaction of analgesia and sedation ot their effect on the prognosis of surgical patients still need to be elucidated.Currently, how to optimize intra-operative Analgesia and sedation to improve the prognosis of surgical patients is still a mystery.Intra-operative nerve block provided regional analgesia of the operated knee, which reduced the dosages of sedatives and analgesics.Based on a pilot study,the investigators found a decrease of post-operative adverse composite outcomes with the use of continuous femoral nerve block (2% versus 7%) ,therefore, the investigators postulate that general analgesia with lighter sedation in combination with peripheral nerve block could reduce the post-operative morbidity compared with deeper sedation.This randomized controlled trial is designed to test this hypothesis in patients receiving unilateral knee arthroplasty.