Effects of dexmedetomidine on postoperative cognitive function in elderly patients undergoing general anesthesia

Objective To investigate the effect of dexmedetomidine on postoperative cognitive function in elderly patients undergoing general anesthesia. Methods A total of 100 elderly patients undergoing elective surgery were enrolled.The patients were randomly divided into observation group and control group, with 50 patients in each group.The observation group was given dexmedetomidine+ 0.9% sodium chloride injection before induction anesthesia.The control group was given 0.9% sodium chloride injection.The remaining anesthesia induction and maintenance time were same in the two groups.The cognitive function and postoperative cognitive dysfunction(POCD) were evaluated by MMSE scale.The blood pressure and heart rate before and after operation and at the end of the operation, the levels of serum tumor necrosis factor α(TNF-α) before operation, at the end of the operation and postoperative 3, 7 days were measured. Results At postoperative 1 day and 3 days, the MMSE scores of the observation group were (24.6±0.7) points and (27.2±1.1) points, respectively, which were significantly higher than those of the control group [(22.4±0.6) points, (27.2±1.1) points, t=3.64, 3.97, all P<0.05]. And 6 cases in the observation group occurred cognitive dysfunction, which was significantly lower than 20 cases of the control group (χ2=5.38, P<0.05). At the end of the operation and postoperative 3 days, the serum levels of TNF-α in the observation group were (28.52±3.73)ng/L, (28.82±4.13)ng/L, respectively, which were significantly lower than those in the control group[(37.14±3.62)ng/L, (38.27±3.47)ng/L, t=5.21, 4.89, all P<0.05]. At the beginning of the operation, the systolic blood pressure, diastolic blood pressure, heart rate of the observation group were (124.53±3.84) mmHg, (79.32±4.38) mmHg, (70.45±5.32) times/min, respectively, which were significantly lower than those of the control group[(145.36±4.72)mmHg, (93.17±3.82) mmHg, (86.79±4.26) times/min], the differences were statistically significant(t=5.83, 4.97, 4.58, all P<0.05). Conclusion In the elderly patients undergoing general anesthesia, the use of pumped dexmedetomidine has little effect on the postoperative cognitive function.The mechanism may be related to stabilizing the blood flow dynamics, decrease the high expression of TNF-α, which is worthy of clinical application. Key words: Dexmedetomidine; Elderly; General anesthesia; Cognitive function