Effects Of Goal-directed Fluid Therapy On Cerebral Oxygen Metabolism And Postoperative Cognitive Function In Elderly Patients Undergoing Lumbar Surgery

Objective:To explore the effects of goal-directed fluid therapy on cerebral oxygen metabolism and postoperative cognitive function in elderly patients undergoing lumbar surgery.Methods:From January 2019 to January 2020,60 cases of patients aged 65 to 80 years old were selected from the Second Hospital of Shanxi Medical University,who were in ASA II^III.All cases were divided into Intervention and Control groups by the table of random numbers,30 cases in each group.Intervention group was the Goal-directed fluid therapy group,stroke volume variation（SVV）and cardiac index（CI）were used as volume index,control group was the traditional fluid therapy group.At time before anesthesia induction（T1）,operation beginning time（T2）,1h after operation was began（T3）,the end of surgery（T4）,30min after anesthesia（T5）,blood samples were collected,including arterial and central venous blood for blood gas analysis,the total input,intraoperative crystalline fluid and colloidal fluid dosage,haemorrhage,urine volume,frequency of hypotension,hemoglobin concentration（Hb）,lactic acid content（Lac）,central venous oxygen saturation（Scv O₂）,local cerebral oxygen saturation（r SO₂）were recorded and calculate oxygen uptake rate（O₂ER）of the two groups.The differences among two groups were compared.Neuropsychological tests were performed 1 day before surgery,1 day after surgery,and 7 days after surgery to evaluate patients’cognitive function.Results:All patients’general information（age,gender,BMI,ASA grade,operative duration）was no statistical difference between the groups（P>0.05）.The crystal input volume,total fluid input volume,urine volume and frequency of hypotension in the intervention group,were lower than those in the control group,（P<0.05）.r SO₂at different time points was compared,except for T3 time point,there was no significant difference（P>0.05）.At T3 time point,r SO₂in the intervention group was higher than that in the control group（P<0.05）.Comparison of O₂ER at different time points showed that there was no statistically significant difference in O₂ER between the two groups at T1 to T2（P>0.05）.At T3 to T5,the intervention group was lower than that in the control group（P<0.05）.Comparison of Scv O₂at different time points showed that there was no statistically significant difference between the two groups at T1 to T2（P>0.05）,but at T3 to T5,Scv O₂in the intervention group was higher than that in the control group,with statistically significant difference（P<0.05）.Comparison of Lac at different time points showed that there was no statistically difference in Lac between the two groups at T1～T2 time points（P>0.05）,but the intervention group was lower at T3～T5 time points,with statistical significance（P<0.05）.MMSE,CDT4 score,TMT-B,immediate recall and other test results of two groups of patients showed statistically differences in 1 day after surgery,and the score of the intervention group was significantly better than that of the control group.There were statistically differences in VFT,SDMT and TMT,delayed short delay recall and long delayed recall in two groups at 1 and 7 days after surgery,and the score of the intervention group was better than that of the control group.Conclusion:Goal-directed fluid therapy is beneficial to reduce the oxygen uptake rate in elderly patients undergoing lumbar surgery,maintain the balance of cerebral oxygen supply and demand,and improve the oxygen metabolism and microcirculation in the whole body,which has a positive significance for improving postoperative cognitive function.