ObjectiveTo evaluate the effects of different doses of dexmedetomidine on the postoperative cognitive dysfunction(POCD) in patients treated with coronary artery bypass transplantation.

MethodsOne hundred and twenty patients scheduled by coronary artery bypass transplantation were divided into the different doses of dexmedetomidine group(group D1, group D2 and group D3) and control group(group C) using the random number table method and double-blind method(30 cases in each group).At 30 min before induction of anesthesia, the dexmedetomidine was intravenously administered to group D1, D2 and D3 with loading doses of 0.2, 0.4 and 0.8 μg/kg, respectively, and then at a rate of 0.5 μg·kg^-1·h^-1 until the end of operation.The group C was given the equal volume 0.9% sodium chloride solution.Before induction of anesthesia after entry(T₀), at the beginning of CPB(T₁), at the end of CPB(T₂), after operation(T₃), after 24 h of operation(T₄) and after 72 h of operation(T₅), the serum levels of tumor necrosis factor-α(TNF-α), interleukin-6(IL-6), neuron-specific enolase(NSE) and central neuron-specific protein(S100β) were detected in all cases, the MMSE scores before 1 day of operation, and after 1, 3 and 7 d of operation were evaluated, and the incidence rate of POCD was calculated.

ResultsThe levels of TNF-α, IL-6, NSE and S100β in group D1, group D2 and group D3 were lower than those in group C(P < 0.05), and the incidence rates of POCD in group D1, group D2 and group D3 were significantly lower than those in group C(P < 0.05).The MMSE scores in group D1, group D2, and group D3 after 1 and 3 days of surgery were higher than those in group C(P < 0.05).

ConclusionsPreoperative administration of dexmedetomidine can significantly reduce the incidence rate of POCD in patients treated with coronary artery bypass transplantation, which may be closely related to the reduction of inflammatory response, and there is not dose correlation with the incidence rate of POCD at the clinical dose.