Effect Of Dexmedetomidine On Postoperative Cognitive Function In Patients With Heart Valve Replacement Surgery

Objective To discuss the effect of dexmedetomidine(DEX) on postoperative cognitive function in patients with heart valve replacement surgery and possible machanism.Methods 90 patients scheduled for heart valve replacement in randomized,double-blind were divided into 3 groups, respectively was the control group(group C,n=30), given DEX 0.3 μg/㎏ group(group D1,n=30), given DEX 0.6 μg/㎏ group(group D2,n=30).All adopted intravenous anesthesia without using any drug before surgery. group D1 and group D2 after tracheal intubation were respectively administrated with DEX 0.3μg/㎏ or 0.6 μg/㎏ in the infusion time of 10 min, followed respectively infusion of0.3 μg/㎏/h or 0.6 μg/㎏/h DEX to closed chest. Group C gave the same volume of saline. Central venous blood were drawn to measure respectively C-reactive protein(CRP), Tumor necrosis factor-α(TNF-α), Interleukin-6(IL-6), Neuron-specific enolase(NSE), S100 B protein(S100-b) before anesthesia induction(T0), postoperative(T1), 3 day post-operation(T2), 7 day post-operation(T3); Mean arterial pressure(MAP)and heart rate(HR) were recorded at the four time points above; The cognitive function of patients in three groups were evaluated respectively by mini-mental state examination(MMSE) and Montreal cognitive assessment(Mo CA) at 1 day pre-operation, T2 and T3. Gender, age, body weight, surgical method, heart function grade, operation time, time of CPB, amount of bleeding during operation, surgical method, heart function grade, the auto-rebeat number of heart, the time from postoperation to tracheal extubation, the time of stay in ICU after operation and hospital stays, the dosage of propofol and sufentanil were recorded.Results Compared with T0, TNF-α, IL-6, S100-b value increased in the T1 time points,NSE value increased in the T1~2 time points, CRP value increased in the T2~3 time points(P<0.05); Compared with group C, TNF-α、IL-6、S100-b value of group D1 and D2 reduced in the T1 time points, NSE value of group D2 reduced in the T1~2 time points,CRP value of group D2 reduced in the T2~3 time points(P<0.05); Compared with group D1, TNF-α、IL-6、S100-b value of group D2 reduced in the T1 time points, NSE value of group D2 reduced in the T1~2 time points, CRP value of group D2 reduced in the T2 time points(P<0.05);Compared with T0, HR value of group D1 and D2 reduced in the T1 time points(P<0.05), Compared with group C, HR value of group D1 and D2 reduced in the T1 time points, and HR value of group D2 was lower group D1(P<0.05);Compared with 1 day pre-operation, score of patients in three groups reduced in the T2~3 time points by MMSE and Mo CA(P<0.05); At T2, by MMSE there were respectively 16, 14 and 13 cases POCD complicated in group C, D1 and D2, by Mo CA there were respectively 18, 15 and 10 cases POCD complicated in group C, D1 and D2,comparision between group D2 and group C had statistical significance by Mo CA(P<0.05); At T3,by MMSE there were respectively 14, 12 and 10 cases POCD complicated in group C, D1 and D2, by Mo CA there were respectively 16, 14 and 10 cases POCD complicated in group C, D1 and D2;Compared with group C, the dosage of propofol in group D1 and D2 reduced, the dosage of sufentanil in group D2 also reduced(P<0.05); Compared with group D1, the dosage of propofol and sufentanil in group D2 were reduced(P<0.05).Conclusion: DEX for patients with heart valve replacement surgery can improve the postoperative cognitive function, especially given DEX 0.6 μg/㎏ group effectively, it is probably connected with nerve protective effect, inhibiting inflammatory reaction,reducing the dosage of general anesthetics and the stable hemodynamic effect.Compared with the MMSE test, Mo CA testing POCD early diagnosis in patients with heart valve replacement surgery is more sensitive.