Prediction Of Volume Responsiveness During Tourniquet Usage In Lower Limbs Orthopedic Surgery By Inferior Vena Cava Respiratory Variability

Objectives:To evaluate the volume change caused by the blood-sucking band in lower extremity orthopedic surgery under general anesthesia mechanical ventilation with Inferior vena cava respiratory variability(VIVC).Material and methods:A single-center prospective study was performed in this study.Eighty patients with lower extremity orthopedic surgery(with blood transfusion in the surgery)who were treated in our hospital from July 2015 to June 2018 were selected as subjects.All patients’ general information such as gender,age,height,weight,body mass index(BMI)were recorded.Heart rate(HR)and systolic blood pressure(Systolic blood pressure)were recorded before and after the use of the tourniquet.Clinical data such as SBP),Diastolic blood pressure(DBP),and Mean arterial pressure(MAP).A portable ultrasound system was used to detect the Stroke volume(SV)of the heart before and after the use of the tourniquet and the inferior vena diameter of inspiratory.The Inferior vena cava diameter of expiratory was recorded asⅣCmax and ⅣCmin,respectively,and VIVC was calculated.The patients were divided into a volumeresponsive(Sensitive,S)group(n=29 cases)and a volume response-insensitive(Insensitive,IS)group(n=51 cases).Univariate analysis of the general data,clinical data,ⅣCmax,ⅣCmin and VIVC of the two groups of patients,using Pearson correlation analysis to analyze the relationship between the use of pre-swept VIVC and SV changes(△SV).The receiver operating characteristic curve(ROC)was used to analyze the efficacy of VIVC to predict △SV.According to the Yoden index,the best diagnostic value was determined and the diagnostic sensitivity and specificity were calculated.Results:(1)There were no significant differences in gender,age,weight,height,BMI and other general data between the two groups(P>0.05).The pre-cardiac rate(HR0)and the upper vascular band were observed in the two groups.Heart rate(HR1),anterior systolic blood pressure(SBP0),supracondylar systolic blood pressure(SBP1),upper venous vasodilatation pressure(DBP0),upper venous vasodilatation pressure(DBP1),upper There was no significant difference in the mean data between the mean arterial pressure(MAP0)and the mean arterial pressure(MAP1)after the upper venous band(P>0.05).(2)SVO was higher in S group than in SV1,and △SV and VIVC were higher in group S than in IS group(P<0.05).(3)VIVC was positively correlated with △SV(r=0.579,P=0.000).(4)The area under the ROC curve(AUC)using VIVC to predict capacity change is 0.832,95%CI:0.731～0.933,P=0.000.When the Jordan index is 0.621,the sensitivity is 0.759 and the specificity is 0.863.The best diagnostic value for VIVC is 0.190.Conclusions:(1)Under the condition of general anesthesia and mechanical ventilation,the application of blood displacement zone in lower limb orthopaedic surgery results in significant changes in SV and VIVC indexes of patients,which indicates that the application of blood displacement zone will cause changes in blood flow volume of patients.(2)this study found that the volume change difference △SV of patients applying blood drive belt in lower limb orthopedic surgery is positively correlated with VIVC,and the ROC is used to analyze the effectiveness of VIVC in predicting the volume change of 80 patients.the area AUC under ROC curve is 0.832,ACU>0.7,which indicates that VIVC has high prediction value.VIVC can be used to accurately judge the volume change of patients applying blood drive belt in lower limb orthopedic surgery,and the best diagnostic value of VIVC is 0.190,i.e.when VIVC>0.190,it needs to be noticed by anesthesiologists.