| Objective:Ultrasound was used to rapidly measure the long diameter of the inferior vena cava（IVC）,the short diameter of the transverse section and the cross-sectional area.The value of preoperative blood volume in elderly patients was evaluated.Methods:A total of 102 elderly patients with gastrointestinal surgery who had spontaneous breathing from January 2017 to February 2018 were selected.The final 90patients were enrolled,aged 65-80 years,BMI 18-25 kg/m2,ASA I-III.The operating room routinely records MAP,HR,and SpO2.The IVC transverse plane long diameter（LD）,transverse plane short diameter（SD）and its cross-sectional area（Area）were measured by ultrasound from subcostal view before surgery,and the ratio of LD to SD as the shape change index（SCI）.local anesthesia was performed under the internal jugular vein puncture and central venous pressure（CVP）of patients at the end of the same period was recorded.According to the preoperative CVP level,the patients were divided into non-hypovolemia group（CVP≥5cmH2O）and hypovolemia group（CVP<5cmH2O）.Pearson correlation analysis and multiple linear regression analysis were used to analyze the correlation between IVC and CVP.The receiver operating characteristic（ROC）curve was drawn to analyzed IVC parameters to predict the blood volume.For patients with hypovolemia,liquid therapy was performed,and ultrasound and CVP were monitored simultaneously.The parameters of IVC and CVP were compared before and after fluid therapy.Results:1.Among the 90 patients,35 patients with low blood volume,accounting for 39%,and55 patients with non-hypovolemia,accounting for 61%;In hypovolemia group,LD,SD,and Area of the IVC were lower than the non-hypovolaemia group（P<0.01）,while SCI was higher than non-hypovolemia group（P<0.01）.2.CVP showed a positive correlation with LD,SD,Area（r=0.346,0.754,0.534,respectively,P<0.01）and a negative correlation with SCI（r=-0.679,P<0.01）.The coefficient of determination（r2）of LD,SD,Area and SCI was 0.120、0.569、0.285、0.461,respectively.Multiple linear regression showed that SCI,SD,and Area had significant effects on CVP（R2=0.65,F=51.93,P<0.01）,and SCI was negatively correlated with CVP（β=-0.350,t=-3.977,P<0.01）,SD was positively correlated with CVP（β=0.410,t=3.895,P<0.01）,and Area was positively correlated with CVP（β=0.182,t=2.222,P<0.05）,while LD had no significant effect on CVP（P>0.05）.3.When the CVP<5 cmH2O was predicted by ROC curve,the area under curve（AUC）of SD,SCI were 0.893 and 0.925,respectively,which was significantly better than LD and Area（0.669,0.717,P<0.01）.The diagnostic threshold of SD was 0.99 cm,sensitivity was 77.1%,and specificity was 94.5%.The diagnostic threshold of SCI was2.02,sensitivity was 82.9%,and specificity was 92.7%.4.LD,SD,SCI,Area and CVP were significantly different in elderly patients with hypovolemia before and after treatment（P<0.05）.Conclusion:Ultrasound measurement of IVC cross section parameters SCI,SD and Area can provide a reference for predicting and treating preoperative blood volume,and SCI and SD predict higher blood volume performance in preoperative elderly patients. |
