The Effect Of Dexmedetomidine On Perioperative Hemodynamics And Cognitive Dysfunction In Elderly Patients Undergoing Lumbar Spine Surgery

Postoperative cognitive dysfunction is one of the common complications of perioperative period in elderly patients.Light patients can recover shortly after surgery and severe cases can cause senile dementia.Dexmedetomidine（DEX）has been widely used in clinical practice,but there are few studies on prevention of cognitive dysfunction in elderly patients after lumbar spine surgery.This study compared intraoperative hemodynamics and postoperative cognition in elderly patients with DEX and without DEX to provide reference for clinical use.Through the application of dexmedetomidine combined with propofol,remifentanil is given intravenous anesthesia and its effect on perioperative hemodynamics and postoperative cognitive dysfunction in elderly patients with spinal surgery is observed.Thirty elderly patients scheduled for elective lumbar surgery between December 2016 and October 2017 were randomly divided into two groups:Group D（DEX）and Group L（physiological saline）,and each group has 15 cases.Group D was given dexmedetomidine loading dose0.5ug·kg^-11 before induction of anesthesia,infusion time was 10 min,subsequently maintainning at a rate of 0.2ug·（kg·h）^-1,DEX was discontinued 30 minutes before the end of surgery.At the same time,group L pump the same amount of 0.9%saline.Two groups of patients were recorded before and after intubation,intubation,extubation,extubation after 1min,leaving PACU（T5）with HR,MAP,SpO2.Blood glucose meter was used to measure the concentration of GLu in two groups of patients at T0,T2 and T4.The intraoperative bleeding,dosage of remifentanil and propofol,the operation time,the anesthesia time during the operation were recorded.The recovery time（t1）,eye opening time（t2）and conscious extubation time（t3）were recorded.Mini-Mental State（MMSE）test was used to assess the cognitive function by the same anesthesiologist 1 day before and 1 day,3 days,7 days after the operation.The incidences of POCD was calculated.The results show that:1、There were no significant differences in the aspects of fundamental state（P>0.05）.2、The operation time,the anesthesia time and the intraoperative bleeding in the two groups had no significant difference between the two groups（P>0.05）.The intraoperative use of propofol in group D was3.4±0.1mg·（kg·h）^-1,which was significantly lower than that in group L(3.7±0.3mg·（kg·h）^-1)（P<0.05）.The use of remifentanil in group D was14.1±2.7ug·（kg·h）^-1,which was significantly lower than that in group L(10.9±2.0ug·（kg·h）^-1)（P<0.05）.3、There was no significant difference in MAP,HR and SpO2 between two groups at T₀（P>0.05）.Compared with T₀,the MAP and HR of group L were significantly increased at T₂ and T₄（P<0.05）;the MAP of group L and D at T₃ was significantly lower（P<0.05）.Compared with group L,at T₂、T₄,MAP in group D was significantly lower and HR significantly decreased（P<0.05）.At T₅,MAP in group D was lower than that in group L（P<0.05）.There was no significant difference in Sp O2 between two groups at different time points（P>0.05）.4、There was no significant difference in GLu concentration between the two groups at T₀（P>0.05）.Compared with T₀,the concentration of GLu at T₂ and T₄ in both groups were significantly increased（P<0.05）.However,compared with L group,the GLu concentration in D group was significantly lower（P<0.05）.5、Compared with group L,the patients in group D had no significant prolongation of t1、t2、t3.Compared with group L,VAS and SAS scores of group D were significantly decreased 5 min after extubation（P<0.05）.6、There was no significant difference in MMSE score between the two groups before operation（P>0.05）.Compared with 1 day before operation,the MMSE scores of the group L at 1 day and 3 days after operation were significantly decreased（P<0.05）.The MMSE scores of the D group at 1 day after operation decreased significantly（P<0.05）.There was no significant decrease in MMSE scores at 3 days and 7 days after operation（P>0.05）.Compared with L group,The MMSE scores of group D were significantly increased on the 1 day after operation（P<0.05）.The MMSE scores of group D on the 3 days,7days after operation were higher than group L,but there was no significant significance（P>0.05）.7.There were 6 patients who developed POCD in L group one day after operation,the incidence rate was 40%.In group D,one patient had POCD one day after operation,the incidence was 6.7%,the difference was statistically significant（P<0.05）.There were 2 patients with POCD in group L at 3 days postoperatively,with a incidence rate of 13.3%.One patient had POCD 7 days after operation,and the incidence was 6.7%.POCD did not occur in group D at 3 days and at 7 days after operation.The incidence of POCD in group D was lower than that in group L,but there was no statistical significance（P>0.05）.From results,the following conclusion can be drawn:Dexmedetomidine can reduce the use of propofol and remifentanil,make the perioperative hemodynamics more stable,and effectively decrease the incidence of postoperative cognitive dysfunction undergoing spinal surgery.