[Effects of different doses of dexmedetomidine on cognitive dysfunction in elderly patients early after laparoscopic surgery for colorectal cancer].
OBJECTIVE
To investigate the effect of different doses of dexmedetomidine (Dex) on early postoperative cognitive dysfunction in elderly patients undergoing laparoscopic surgery for colorectal cancer.


METHODS
Eighty ASAI-III elderly patients (over 65 years) were randomized equally into 4 groups including a control group without dexmedetomidine and 3 dexmedetomidine groups (groups D1, D2, and D3) with loading dexmedetomidine doses of 0.2, 0.5, and 0.8 µg/kg and maintenance doses of 0.2, 0.5, and 0.8 µg·kg(-1)·h(-1), respectively. Dex was discontinued 30 min before the end of surgery. The time of operation, adverse reactions, time from the end of surgery to spontaneous breathing recovery (TR), time from spontaneous breathing recovery to opening eyes (TO), and time from opening eyes to extubation (TE) were recorded. Mini-Mental State (MMSE) test was used to assess the cognitive function 1 day before and at 1 day and 3 days after the operation.


RESULTS
The incidence of postoperative cognitive dysfunction (POCD) was significantly lower in groups D2 and D3 than in the control group and group D1 (P<0.05). The incidences of hypotension and bradycardia were the highest in group D3 (P<0.05), which also had longer significantly TO and TE than the other 3 groups (P<0.05).


CONCLUSIONS
Dexmedetomidine with a loading dose of 0.5 µg/kg followed by maintenance doses of 0.5 and 0.8 µg·kg(-1)·h(-1) (preferentially 0.5 µg·kg(-1)·h(-1)) can reduce the incidence of POCD in elderly patients undergoing laparoscopic surgery for colorectal cancer.
Department of Anesthesiology, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China. E-mail: ssss047@163.com.
Yiwen
Y
Zhang
Zumin
Z
Xing
Yinghua
Y
Xu
Shiyuan
S
Xu
D000368:Aged; D003071:Cognition / Q000187:drug effects*; D015179:Colorectal Neoplasms / Q000601:surgery*; D020927:Dexmedetomidine / Q000008:administration & dosage*; D006801:Humans; D010535:Laparoscopy; D011183:Postoperative Complications; D012119:Respiration
D020927:Dexmedetomidine