Effect Of Different Intraoperative Fluid Therapy On Postoperative Delirium In Patients Undergoing Spinal Surgery

AIM The aim of this study was to compare the effect of goal-directed infusion therapy（GDT）with restrictive fluid therapy（RFT）on postoperative delirium（POD）in middle-aged and elderly patients undergoing spinal surgery.METHODS 195 patients of middle-and old-aged（≥50 years old）scheduled for elective spinal surgery were randomly divided into two groups:restrictive fluid therapy group（group RF,n=97）and goal-directed fluid therapy group（group GDT,n=98）.In group RF,lactated Ringer’s solution was firstly administered at 5 m L?kg^-1during the induction of anesthesia,then at 5 m L?kg^-1?h^-1until the end of surgery.For patients in the GDT group,in addition to the initial administration of lactated Ringer’s solution at5m L/kg,the following fluid therapy was adjusted by using noninvasive blood pressure monitoring system（CNAP）to maintain 9%≤Pulse pressure variation（PPV）≤13%.The volume of fluid infusion（including the volume of actated Ringer’s solution and hydroxyethyl starch）,number of blood transfusion,blood transfusion volume and urine volume,blood loss,as well as the usage of vasoactive agents were all recorded during the entire operation.The mean arterial pressure（MAP）,heart rate（HR）,cardiac index（CI）,bispectral index（BIS）and regional cerebral oxygenation index（r SO₂）were recorded at different time points,including before anesthesia induction（T₀）,5 minutes after anesthesia induction（T₁）,when the operation began（T₂）,and at different time（30minutes,60 minutes,90minutes,120minutes）during operation（T₃-T₆）,at the end of operation（T₇）,at 5 minutes after operation（T₈）.Arterial blood samples were collected to test lactic acid（Lac）value at T₂and T₇.The Chinese revised version of delirium diagnosis scale（Confusion Assessment Method-Chinese Reversion,CAM-CR）was used to record the incidence of postoperative delirium 1-3 days after spinal surgery.The visual analog score（（VAS））was applied to analysed the pain 3 days after spinal surgery.And the other postoperative complications and hospital stay were also recorded.RESULTSComparison of main outcome measures:There were 12 cases of postoperative delirium in group RF and 4 cases in group GDT.The overall incidence of postoperative delirium was 8.1%,with 12.4%in group RF,8%in group GDT.（P<0.05）.Comparison of hemodynamics and r SO₂during operation:Compared with T₀,r SO₂in group RF was increased at T₂-T₄but decreased at T₅-T₈,while compared with T₀,r SO₂in group GDT was increased at T₁-T₈（P<0.05）.Compared with T₀,MAP,CI and BIS in both groups were decreased at T₁-T₈（P<0.05）.Compared with T₀,HR in both groups was decreased at T₁-T₇but increased at T₈（P<0.05）.Compared with group RF,MAP and r SO₂were increased at T₅-T₈in group GDT.Compared with group RF,CI and HR were increased at T₆-T₈in group GDT（P<0.05）.There was no significant difference in BIS between the RF group and the GDTgroup（P>0.05）.Comparison of intraoperative fluid volume,vasoactive drugs and lactic acid:Compared with RF group,the total volume of intraoperative infusion,sodium lactate Ringer injection and urine output in GDT group were significantly increased,but the usage of ephedrine was decreased（P<0.05）.There was no significant difference in intraoperative colloid dosage（dosage of hydroxyethyl starch solution）and blood loss between the two groups（P>0.05）.Compared with RF group,the lactic acid value of GDT group was significantly lower after operation.Comparison of postoperative complications,length of hospital stay and analgesic effect:Compared with RF group,the incidence of POD and the length of hospital stay was lower in GDT group（P<0.05）.There was no significant difference in PONV,hypotension and acute kidney injury between the two groups（P>0.05）.The VAS scores of the two groups decreased gradually on the 3rd day after operation（P<0.05）,but there was no significant difference between the two groups（P>0.05）.Conclusion Compared with restrictive fluid therapy,goal-directed fluid therapy can maintain perioperative hemodynamic stability,improve cardiac index,maintain stable cerebral oxygen supply and demand,reduce the incidence of POD and shorten hospital stay.