Effects of low-dose dexmedetomidine and sub-anesthesia ketamine on cognitive function after laparoscopic general anesthesia in elderly patients with chronic alcohol consumption

Objective To compare the effects of low-dose dexmedetomidine and subanesthesia ketamine on prevention of cognitive dysfunction after laparoscopic general anesthesia in elderly patients with chronic alcohol consumption. Methods Sixty patients over 60 years old and ASA Ⅰ~Ⅱ, underwent elective laparoscopic cholecystectomy under general anesthesia were enrolled, they were randomly divided into three groups: group D (dexmedetomidine group), group K (ketamine group) and group C (saline). Adjustment of propofol and remifentanil dosage based on hemodynamic parameters. Intraoperative bispectral index(BIS) of three groups sustained in 40-50. Group D: dexmedetomidine 0.5 μg/(kg·min), group K: ketamine 2.0 μg/(kg·min), group C: equivalent saline and dosages were constant during operation. The times of pulling laryngeal mask air-way out and revival after drug discontinuance were recorded for every group. The neuropsychological function was evaluated by MMSE at one day before operation, one day after operation, three days after operation and five days after operation. Postoperative score less 2 points than preoperative score that was identified as postoperative cognitive dysfunction(POCD). Results The recovery time and extubation time after anesthesia in group C were significantly less than those in group D and group K(P<0.05). MMSE scores of the three groups: compared with one day before operation, MMSE scores of group C and K decreased significantly at 1 d and 3 d after operation, the difference was statistically significant(P<0.05); Compared with group D, MMSE scores of group C and group K were significantly lower than those of group D(P<0.05). Compared with 1 d and 3 d after operation, the incidence of POCD in group D was lower than that in group C, the difference was statistically significant (P<0.05). Conclusions Low-dose dexmedetomidine has a protective effect on postoperative cognitive dysfunction and can reduce the incidence of postoperative cognitive dusfunction after laparoscopic general anesthesia in elderly patients with chronic alcohol consumption. Key words: Postoperative cognitive dysfunction; Ketamine; Dexmedetomidine; Elderly patient; Chronic alcohol consumption