Study Of Brain Natriuretic Peptide Combined With Inferior Vena Cava Respiratory Variability Index In Predicting Fluid Responsiveness In Patients With Septic Shock

Objective:To investigate the clinical value of B-type natriuretic peptide?BNP?combined with inferior vena cava respiratory variation index?IVC-RVI?in evaluating the fluid responsiveness of patients with septic shock.Methods:A total of 56 patients with septic shock who were admitted to Shihezi people's Hospital and First Affiliated Hospital,School of Medicine,Shihezi University from October 2018 to December 2019 were selected as the research subjects.All patients with septic shock performed fluid resuscitation in accordance with the latest sepsis guidelines.The change of cardiac output was observed 30 minutes later.According to the increase of cardiac output?CO?before and after fluid challenge,patients were divided into two groups:reactive?R?group??CO?15%?and non reactive?NR?group??CO<15%?.The mean arterial pressure?MAP?,heart rate?HR?,brain natriuretic peptide?BNP?,maximum value(D_max)and minimum value(D_min)of the inferior vena cava diameter before and after fluid challenge were recorded,and the inferior vena cava respiratory variability index was calculated.The changes of each index and the differences between the two groups were compared before and after fluid challenge.At the same time,the receiver operating characteristic curve?ROC curve?was drawn to analyze the value of BNP and RVI in predicting volume responsiveness.Results:There were 23 patients in the R group and 33 patients in the NR group.There was no significant difference in general information between the two groups of patients?P>0.05?.Before fluid challenge,there was no significant difference in CO,HR,MAP and BNP between the two groups of patients?P>0.05?.The D_maxand D_minof the NR group were greater than those of the R group,and the IVC-RVI of the R group was greater than that of the NR group.The difference was statistically significant?P<0.05?.After fluid challenge,there was no significant difference in MAP,HR,BNP and CO between the two groups?P>0.05?.The Dmax,and Dmin of the NR group were larger than those of the R group,and the IVC-RVI of the R group was larger than that of the NR group.The difference was statistically significant?P<0.05?.There was no significant difference in the changes of MAP,HR,Dmax,and Dmin before and after fluid challenge?P>0.05?.The change of BNP??BNP?in NR group was larger than that in R group,and the difference was statistically significant?P<0.05?.Correlation analysis showed that Dmin and Dmax were negatively correlated with?CO,and IVC-RVI was positively correlated with?CO?P<0.05?.The area under the ROC curve?AUC?for IVC-RVI prediction of fluid responsiveness was 0.967,and the cut-off value,sensitivity and specificity were 43.8%,91.3%and 93.9%respectively.The AUC of?BNP predicted fluid responsiveness was 0.734,and the cut-off value,sensitivity and specificity were-76.5 pg/mL,56.5%and 84.8%respectively.The AUC,sensitivity and specificity of combined?BNP and IVC-RVI were 0.968,91.3%and 93.9%respectively.Conclusion:1.IVC-RVI may has a good effect on fluid responsiveness assessment in patients with septic shock,and is better than?BNP.2.The baseline value of BNP cannot be used as an indicator to predict fluid responsiveness in patients with septic shock,but the dynamic level of BNP may be helpful in predicting fluid responsiveness.3.The value of the combined prediction of fluid reactivity was not significantly changed compared with the use of IVC-RVI alone.