| Objective To observe the effects of preemptive analgesia with continuous femoral nerve block(CFNB) after total knee arthroplasty( TKA) in elderly patients on early postoperative cognitive function. Methods Sixty patients aged more than 60 years with American society of anesthesiologists(ASA) physical status I~Ⅱ, who were scheduled for elective total knee arthroplasty, were randomized into 2 groups(n=30): preemptive analgesia group and control group with total intravenous anesthesia. Preemptive analgesia group was implemented CFNB before surgery, while control group was done CFNB after surgery. Patient’s general information before operation was recorded. The changes of circulation function was monitored during operation. The doses of all drugs used for anesthesia, the time of operation, tourniquet and anesthesia were also recorded. Cognitive function was measured on 1 day before surgery, 1 day, 3 day, 5 day and 7 day after surgery using mini-mental state examination(MMSE). The occurrence of POCD was defined when the decreased MMSE score after surgery was more than one standard deviation. The visual analog scale(VAS) at the same days in resting and exercise were recorded to evaluate the degrees of postoperative pain. Results The total dosage of remifentanil in preemptive analgesia group(1.7±0.4)mg was less than that of control group(1.9±0.3)mg(P <0.05);VAS exercise score in preemptive analgesia group were lower than that of control group on3 day, 7 day after operation(P <0.01); VAS resting scores after operation in two groups were no significant differences(P >0.05). The incidence of POCD in preemptive analgesia group(6.7%) was lower than that of control group 3d after operation(26.7%)(P <0.05);Conclusions The preemptive analgesia produced by preoperative CFNB can improve the recovery of early postoperative cognitive function in elderly patients performed TKA. This can be related to decrease the degree of postoperative exercise pain. |
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