Effect Of Dexmedetomidine On Cerebral Oxygen Saturation And Postoperative Delirium In Elderly Patiens

Objective:To investigate the effect of dexmedetomidine on the changes of intraoperative regional cerebral oxygen saturation?rScO₂?,and on postoperative delirium?POD?in elderly patients undergoing elective non-cardiac surgery.Methods:A total of 100 patients undergoing elective non-cardiac surgery under general anesthesia were enrolled.Patients with ASA grade II or III,aged 65 years and above,and MMSE scores of 17 or more before surgery were enrolled in this study.The patients were randomly divided into 2 groups?n=50?:dexmedetomidine group?group D?and saline control group?group C?.Tracheal intubation general anesthesia was performed with multi-modal monitoring including FORE-SIGHT NIRS.Dexmedetomidine was infused in group D at a loading dose of 0.4?g/kg 10 min before induction of anesthesia.After 10 min,infusion of 0.4?g·kg^-1·h^-11 was continued for 30 min before closing;Group C was given equal volume of saline.Patients were evaluated daily by CAM-CR within 3 days after surgery?including the day of surgery?.Record the time of OR entery?T0?,dexmedetomidine or saline infusion after 10 min?T1?,tracheal intubation?T2?,the beginning of surgery?T3?,after tracheal intubation?T4?of the local brain Oxygen saturation?rScO₂?,heart rate?HR?,mean arterial pressure?MAP?.Continuous recording of intraoperative rScO₂changes,and calculate the average rScO₂?rScO₂a?,the minimum value of rScO₂?rScO₂min?,and the percentage of the minimum value of rScO₂ over the mean decrease??rScO₂%?.The patients were evaluated on the day after surgery,postoperative 1d,postoperative 2d,postoperative 3d and postoperative 3d of the incidence of delirium and postoperative 3d the total incidence of delirium.In addition,the operation duration and anesthesia duration,intraoperative blood loss,intraoperative anesthetic drug usage and so on.Results:Compared with T0,the HR of T1 in group D was significantly decreased,and the HR and MAP of T2,T3 and T4 in group C were significantly increased?P<0.05?.Compared with T0 and T1,rScO₂ in T2,T3 and T4 groups increased significantly?P<0.05?.In two groups of patients,rScO₂a,rScO₂min,?rScO₂%value had no significant difference?P>0.05?.Compared with group C,the incidence of delirium was significantly lower in group D at the day after operation?P<0.05?,while the incidence of POD at the 1d,the 2d and the 3d after operation in both groups had no significantly difference?P>0.05?.There was no significant difference in the overall incidence of POD?P>0.05?.Conclusion:Intraoperative infusion of dexmedetomidine has no significant effect on intraoperative rScO₂,but it can prevent the occurrence of delirium within one day after operation.In addition,dexmedetomidine has the effect of reducing the dosage of narcotic drugs,alleviating the stress reaction and stabilizing the hemodynamic changes.