The Effects Of Dexmedetomidine On The Postoperative Outcome In Elderly Patients With Fragile Brain After Gastroenteric Surgery Based On The Multimodal Intraoperative Monitoring

Objective Fragile brain is the most common phenomenon seen in the elderly, the elderly patients with fragile brain is an important risk factor for postoperative outcome.Multimodal intraoperative monitoring in high risk patients in an attempt to reduce the incidence of delirium and cognitive dysfunction,significant predictor of poor outcome.Dexmedetomidine may be neuroprotective,and its use has been linked to decreased postoperative delirium and cognitive dysfunction.This study was desiged to investigate the effects of dexmedetomidine based on the Multimodal intraoperative monitoring on the postoperative outcome in elderly patients with fragile brain undergoing selective gastroenteric surgical procedures.Methods One hundred and twenty cases of elderly patients with fragile brain,aged65-85 yr,weighing 50-80 kg,ASAⅡorⅢ,the score of preoperative Mini-Mental State Examination illiteracy>17,primary>20 and Junior high schooland above>24,scheduled for selective gastroenteric surgical procedures were enrolled in this study.The patients were randomly assigned to two groups(n=60):Control group(group C) and Dexmedetomidine group(group D).Total intravenous anesthesia based on the multimodal intraoperative monitoring was used during anesthesia.In group D,the loading dose of dexmedetomidine 0.4μg/kg was intravenously infused in10 minutes before anesthesia induction,then continuous intravenous injection at 0.4μg·kg-1·h-1 via a pump to 30 minutes before the end of surgery.While in group C,the equal volume of 0.9% nomal saline was given instead of dexmedetomidine.During maintenance of anesthesia,to adjusted maintain the BIS value between 45 and60,region cerebal oxygen saturation was above 54%,mean blood pressure(MAP)from baseline to 20% increased above baseline.The dosages of propofol,sufentanil,remifentanil and vasodilatation by medicationl were recorded.Times from the end of anesthesia to eye opening,extubation,postanesthesia care unit(PACU) discharge,recovery of gastrointestinal function,length of hospital stay were recorded.HR,MAP were recorded at the baseline(T0),after the loading dose of dexmedetomidine or 0.9% normal saline(T1),one minute after intubation(T2),the began of surgery(T3),the end of surgery(T4) and one minute after extubation( T5).The blood samples were collected from radial artery for blood gas analysis at different times,such as before operation,one hour after the operation began and end of surgery.Ramsay scores and VAS scores after surgery 10 minutes,1h,6h,1d,2d were recored.Postoperative delirium(POD) and postoperative cognitive dysfunction(POCD)were assessed using Confusion Assessment Method(CAM) and Mini-Mental State Examination(MMSE) respectively.Classification of surgical complications within30-days were recorded.Statistical analysis was performed by using SPSS13.0 software package.P<0.05 was considered statistically significant.Results Compared with group C,the dosages of propofol,remifentanil were decreased significantly in group D,the utilization rate of atropine is higher and nicardipine is lower significantly in group D.The duration of eye opening,postanesthesia care unit(PACU) discharge and hospital stay after surgery were significantly shorter in group D(P<0.05).Compared with T0 point,HR was significantly lower in group D at T1,HR and MAP were significantly higher in group C at T2,T3,T5.Compared with before operation,Glucose(GLU) in both groups were higher one hour after the operation began,and in group C GLU was significantly higher than that in group D(P<0.05).Ramsay scores after surgery 1h,6h,24 h in group D were significantly higher than group C(P<0.05).VAS scores of group D after surgery 10 min,1h,6h,24 h,48h were significantly lower than that in group C(P<0.05).Compared with group C,the incidence of POD was significantly lower in group D,as well as grade Ⅰcomplications(P<0.05).There was no significant difference in POCD between the two groups(P>0.05).Conclusion Dexmedetomidine can reduce the dosages of propofol and remifentanil,shorten the times to eye opening and length of hospital stay after surgery,improve Ramsay scores and decrease VAS scores,hemodynamics stability.Dexmedetomidine is effective on postoperative delirium and grade Ⅰsurgical complications within 30-days in elderly patients with fragile brain based on the Multimodal intraoperative monitoring undergoing gastroenteric surgical procedures.