Effect of different doses of dexmedetomidine on early postoperative cognitive function in elderly patients treated with lung cancer operation

Objective: To study the effects of dexmedetomidine(Dex) on early postoperative cognitive function in elderly patients treated with lung cancer operation,and its correlation with the anesthetic drug dose.Methods: Sixty elderly patients scheduled by lobectomy or pneumonectomy under general anesthesia were randomly divided into the control group(group C),low dose Dex group(group LD),middle dose Dex group(group MD) and high dose Dex group(group HD)(15 cases each group).The mean arterial pressure,heart rate and blood oxygen saturation in all patients were detected before anesthesia induction(T₀),opening the chest(T₁),end of operation(T₂) and 1 d after operation LD(T₃).The postoperative cognitive function in four groups were measured using mini-mental state examination method(MMSE) 1 d before operation,and 1 d,3 d and 7 d after operation.The sedation scores of all patients were recorded using the Sedation-Agitation Scale in postanesthesia care unit(PACU).Results: Compared with the T₀ time-point,the mean arterial pressure at T₁ in group C significantly increased(P<0.01),and the heart rate at T₂ and T₃ in LD,MD and HD groups decreased(P<0.05 to P<0.01).Compared with the group C,the heart rate at T₁ to T₃ decreased(P<0.05 to P<0.01).The differences of the PACU scores between four groups were not statistically significant(P>0.05).Compared 1 d before operation,the MMSE score in group C decreased significantly 1 d after operation(P<0.01).Compared with group C,the MMSE scores in other three groups significantly increased 1 d after operation(P<0.01).The differences of the incidences of postoperative cognitive dysfunction between four groups were statistically significant 1 d after operation(P<0.05).Conclusions: The application of Dex in elderly patients treated with lobectomy or pneumonectomy can maintan the hemodynamic stability,and reduce the incidence of postoperative cognitive dysfunction,which has no obvious dependence on the anesthetic drug dose.