The Effects Of Dexmedetomidine On Postoperative Delirium In Elderly Patients Undergoing Radical Operation For Colon Cancer

Postoperative delirium (POD) is an acute state of temporary neurologicaldysfunction, associated with a series of symptoms, such as significant cognitivedysfunction, decreased level of consciousness, inattention, the sleep-wake cycledisorders. In elderly patients undergoing major elective surgery, the incidence ofpostoperative delirium is from10%to40%, and the incidence of delirium is animportant indicator which predicts a longer length of stay and more expensive athospital. Dexmedetomidine is efficiently and highly selective α2-adrenoceptor agonist,and has the effects of sedative, analgesic, anti-sympathetic, reducing stress, stablinghemodynamic, as well as neuroprotection. However, the impact of dexmedetomidineon postoperative delirium is still controversial. This study intends to investigate theeffects of the application of intraoperative and postoperative adjuvant givendexmedetomidine on postoperative delirium in elderly patients undergoing radicaloperation for colon cancer, so that evaluating its efficacy and safety in the preventionand treatment of postoperative delirium in elderly patients.Objective：to investigate the effects of dexmedetomidine on postoperativedelirium in elderly patients undergoing radical operation for colon cancer.Methods：Ninety, ASA Ⅱ or Ⅲ, Patients, aged65～80yr, with a body massindex of20～25kg/m2, scheduled for elective radical operation for colon cancerunder general anesthesia, were randomly divided into3groups (n=30each):dexmedetomidine1group (group D1),dexmedetomidine2group (group D2) andcontrol group (group C). The loading dose of dexmedetomidine0.3μg/kg was infusedintravenously15min prior to anesthesia induction, followed by infusion at0.2μg·kg-1·h-1until30min before the end of operation in groups D1and D2.Theequal volume and rate of saline was given in group C. Three groups were given thesame induction and maintenance of anesthesia. At the end of operation, every patientwas given patient controlled intravenous analgesia (PCIA). Group D1: sufentanil 2.0μg/kg+dexmedetomidine0.04μg kg-1h-1+ramosetron0.6mg；groups D2and C:sufentanil2.0μg/kg+ramosetron0.6mg. The three groups were diluted with saline to100ml. The blood pressure, heart rate, SPO2during operation, the volume of bloodloss, the time of operative and recovery, the adverse reactions after surgery wererecorded. At6h，1d，2d and3d postoperatively, the VAS of pain-scores at resting andactivities, scores of sleep, as well as the occurrence of delirium within3d afteroperation were assessed and recorded.Results：Using SPSS15.0statistical software for analysis. Measurement data asmean±standard deviation（±s），the groups were compared using ANOVA. Countdata were compared with tests. P <0.05was considered statistically significant.Compared with group C, there were no significant differences in blood pressure, heartrate, SPO2, the time of operative and recovery, the volume of blood loss during theoperation and the adverse reactions after surgery in groups D1and D2(P>0.05).Compared with group C, the VAS of pain-scores at resting and activities，scores ofsleep, as well as the incidence of delirium within three days after surgery weresignificantly reduced in group D1(P<0.05), at6h postoperatively the score of sleepand the incidence of delirium during the recovery from anesthesia were decreased ingroup D2(P<0.05), while there were no significant differences in the VAS ofpain-scores at resting and activities at each time point, as well as the incidence ofdelirium in the first1~3days after surgery (P>0.05). Compared with group D2, theincidence of delirium in the first1~3days after surgery was reduced in groupD1(P<0.05).Conclusions：1. Dexmedetomidine given small doses of used in general anesthesia duringoperation may reduce the incidence of postoperative delirium during the recoveryfrom anesthesia in elderly patients undergoing radical operation for colon cancer.2. Dexmedetomidine given small doses of combined application of intraoperativegeneral anesthesia and postoperative patient-controlled intravenous analgesia， mayreduce the incidence of postoperative delirium in elderly patients undergoing radicaloperation for colon cancer.