Effects Of Dexmedetomidine Infusion At Different Times And Psychological Suggestion On Postoperative Delirium In Elderly Patients

Objective:In the prevention and treatment of postoperative delirium,dexmedetomidine has been widely used due to its good effects,but there is no exact conclusion about the optimal time of using dexmedetomidine.This research aims to explore the optimal time of using dexmedetomidine and psychological suggestion for the prevention and treatment of postoperative delirium and the influence of symptoms related to the recovery period of general anesthesia,so as to guide clinical medication.Methods:A total of 150 elderly patients who underwent general anesthesia for non-cardiac surgery were selected.Inclusion criteria:（1）Age≥65years;（2）American Association of Anesthesiologists（ASA）gradeⅠ～Ⅲ;（3）body mass index:18kg/m²≤BMI≤30kg/m².The patients were divided into 5 groups with 30 patients in each group,which were D₁group（Dexmedetomidine was pumped 15 minutes before anesthesia induction）,D₂group（Dexmedetomidine was pumped from the beginning of anesthesia induction to 30minutes before the end of the operation）,D₃group（Dexmedetomidine pumped 30minutes before the end of the operation to the end of the operation）,S₁group（Positive psychological suggestion was given preoperatively,and the same dose of 0.9%sodium chloride injection was continuously pumped in all corresponding time periods）,and S₂group（The same dose of 0.9%sodium chloride injection was continuously pumped for all corresponding periods without positive psychological suggestion）.After entering the operating room,all selected patients were set up an venous channel and connected to ECG monitoring,and each group of patients should be treated separately during the operation.Mean arterial pressure（MAP）,heart rate（HR）and other data at 5 different times during the operation were recorded for all patients,T0（before anesthesia induction）、T1（before endotracheal intubation）、T2（immediately after intubation）、T3（before endotracheal extubation）and T4（immediately after endotracheal extubation）;Recording the time of duration of operation and extubation after operation（from drug withdrawal to endotracheal intubation removal）;Postoperative general data such as gender,age,BMI,ASA grade were collected,Ricker sedation-agitation score（SAS score）and VAS pain score were collected.Finally,the incidence of postoperative delirium and the duration of postoperative delirium in each group were recorded before1 day and 3 consecutive days after surgery judging by CAM-CR.Results:（1）General information:There were no significant differences with gender,age,BMI,ASA grade and the duration of operation in each index（P>0.05）.（2）Extubation time:The extubation time in D₁,D₂and S₂groups were significantly shortened than D₃group,with statistically significant difference（P<0.05）.However,there was no significant difference between S₁and S₂groups and D1 and D2 groups（P>0.05）.（3）SAS score:SAS scores of the patients in S₂group were significantly higher than other four groups,with statistically significant difference（P<0.05）.However,only D₁group was significantly higher than D₃group among the comparison of D₁,D₂and D₃groups,with statistically significant difference（P<0.05）.（4）VAS score:VAS score of the patients in S₂group were significantly higher than other four groups,with statistically significant difference（P<0.05）.However,there was no significant difference among the comparison of D₁,D₂and D₃groups（P>0.05）.（5）Hemodynamics（about MAP and HR）:At T0,there were no statistically significant differences among the five groups（P>0.05）.At T1,D₁group were significantly higher than other groups,with statistically significant difference（P<0.05）.However,there were no statistically significant differences among other groups（P>0.05）.At T2,D₁group were significantly lower than other groups,with statistically significant difference（P<0.05）.However,there were no statistically significant differences among other groups（P>0.05）.At T3,there were no statistically significant differences among the five groups（P>0.05）.At T4,D₃group were significantly lower than other groups,with statistically significant difference（P<0.05）.However,there were no statistically significant differences among other groups（P>0.05）.（6）Incidence of postoperative delirium:patients with postoperative delirium in D₁and D₂groups were significantly less than other groups,with statistically significant difference（P<0.05）.However,there were no statistically significant differences between D₁、D₂groups and among other groups（P>0.05）.Postoperative delirium duration:Postoperative delirium duration of patients in D₁,D₂and D₃groups were significantly shorter than S₂group,with statistically significant difference（P<0.05）.However,there were no statistically significant differences between D₁,D₂,D₃groups and S₁,S₂groups（P>0.05）.postoperative delirium duration in D₁,D₂and D₃groups was but there was no significant difference in postoperative delirium duration between groups D₁,D₂and D₃and between groups S₁and S₂（P>0.05）.Conclusion:1.In elderly patients undergoing non-cardiac surgery under general anesthesia,dexmedetomidine can stabilize the hemodynamics,reduce the incidence and duration of postoperative delirium,and have effect on reducing pain and agitation during the recovery period.Using dexmedetomidine at 30min before the end of surgery is more effective in reducing the agitation during the recovery period,but it resulted in prolonged extubation time.Using dexmedetomidine before induction of anesthesia or from induction of anesthesia to 30 minutes before the end of surgery is more effective in reducing the incidence of postoperative delirium.2.Preoperative positive psychological suggestion can also reduce the pain and agitation during the recovery period of elderly patients undergoing non-cardiac surgery under general anesthesia,but it has no significant effect on postoperative extubation time,hemodynamic stability,occurrence and duration of postoperative delirium.