Effect Of Intraoperative PVI-Guided Fluid Therapy On Tissue Perfusion And Prognosis In Elderly Patients Undergoing Gastrointestinal Surgery

Objective:To observe the effect of intraoperative fluid therapy guided by pulse perfusion variation index（PVI）on intraoperative hemodynamic lactate value and postoperative complications in elderly patients undergoing gastrointestinal surgery,and to explore whether PVI-directed fluid therapy can improve tissue perfusion and reduce postoperative complications in these patients.Methods:A total of 160 elderly patients who underwent gastrointestinal surgery under elective general anesthesia at Peking University Shenzhen Hospital from November 2017 to December 2020 were selected and randomly divided into routine fluid therapy group（Group C,n=80）and PVI-guided fluid therapy group（Group PVI,n=80）.Those patients in Group C used routine monitoring methods to maintain MAP65-100mm Hg,CVP5-10mm Hg,urine output>0.5ml·kg^-1·h^-1;Those patients in PVI group used Masimo Rainbow SET to monitor PVI,maintained PVI≤13%,MAP65-100mm Hg,urine output>0.5ml·kg^-1·h^-1.The anesthesia induction and anesthesia maintenance protocols were the same in two groups.MAP and HR were observed and recorded at 5 time points before anesthesia induction（T0）,after intubation（T1）,skin incision（T2）,end of operation（T3）,discharge from the anesthesia recovery room（PACU）（T4）in the two groups.Monitor the blood gas analysis and lactate value at 3 time points of skin incision（T2）,end of operation（T3）,and exit from PACU（T4）in the two groups;record the usage of vasoactive agent and the incidence of hypotension during operation;follow-up after operation time to first flatus,time of firstliquid intake,time of first ground activity,postoperative hospital stay,hospital stay and complications within 30 days after surgery.Results:（1）There were no significant differences in baseline data such as age,gender,body mass index（BMI）,ASA classification,NYHA cardiac function classification,smoking,drinking and comorbidities between the two groups.There was no statistical difference between the two groups in terms of operation type,operation method,operation time,and anesthesia time.The total fluid volume and crystalloid volume infused in the PVI group were less than those in the conventional infusion group（P values 0.004 and 0.009,respectively）.There was no significant difference in the volume of colloid infusion,blood product input,blood loss and urine volume between the two groups.（2）There was no statistical difference in MAP and HR between the two groups during the operation;there was no statistical difference in the use of vasoactive drugs during the operation and the proportion of patients with hypotension during the operation between the two groups.There was no significant difference in PH value,BE,Hco3-and Lactate between T2,T3 and T4 groups in blood gas analysis.Compared with T2,the lactate value increased at T4（all P values were<0.001）.（3）The total incidence of complications and various complications（including postoperative nausea and vomiting,surgical site infection,sepsis,anastomotic leakage,central nervous system complications,pulmonary complications,cardiac rhythm Abnormalities,myocardial ischemia,acute kidney injury,deep vein thrombosis）were not statistically different.There was no statistical difference in the two groups in terms of postoperative ICU admission and postoperative mortality between the two groups.There was no statistical difference between the two groups in the time of the first exhaust,the time of fluid intake,and the time of the first exercise.There was no statistical difference in hospital stay between the two groups.Conclusion:Compared with conventional infusion regimens,PVI-guided fluid therapy can reduce the amount of intraoperative infusion in elderly patients undergoing gastrointestinal surgery,but does not affect intraoperative tissue perfusion and intraoperative hemodynamics.The PVI-guided fluid infusion strategy does not reduce complications and mortality,and does not shorten the length of stay.