Predictive Value of Color Doppler Ultrasound for Acute Kidney Injury in Patients with Septic Shock

Abstract

Background Septic shock may lead to renal perfusion abnormalities, and even acute kidney injury (AKI) , seriously threatening the life of patients. Color Doppler ultrasound (CDU) can be used as a tool to evaluate changes of renal blood flow. However, there are few studies on its evaluation value for AKI in patients with septic shock. Objective To examine the value of CDU in assessing AKI and hemodynamic changes in patients with septic shock. Methods Participants were recruited from Xuzhou Central Hospital between June 2019 and July 2021, including 105 patients with septic shock, and 58 physical examinees. The general demographics and renal hemodynamic indices measured by CDU 〔the luminal diameter of renal artery (D) , peak systolic velocity (Vs) , end-diastolic velocity (Vd) , resistance index (RI) , pulsatility index (PI) 〕 were collected and compared with the groups. The renal hemodynamic indices were further compared between septic shock patients with and without AKI within 72 h after admission. The predictive value of renal hemodynamic indices for AKI in septic shock was analyzed by receiver operating characteristic (ROC) curve. The influencing factors of AKI in septic shock were explored by univariate and multivariate Logistic regression analyses. Then associations of the severity of AKI (stage 1, 2, 3 AKI) with renal hemodynamic indices were analyzed by Spearman rank analysis. Results Thirty-nine septic shock patients had AKI within 72 h after admission, including 19 cases with stage 1 AKI, 15 with stage 2 AKI, and 5 with stage 3 AKI. Septic shock patients had lower D, Vs and Vd, and higher RI and PI than physical examinees (P<0.05) . Septic shock patients with AKI had lower D, Vs and Vd, and higher RI and PI than those without AKI (P<0.05) . AUC of D in predicting AKI in septic shock was 0.782 with 66.67% sensitivity and 80.30% specificity when 4.91 mm was chosen as the optimal cut-off value, that of Vs was 0.772 with 94.87% sensitivity and 51.52% specificity when 71.19 cm/s was chosen as the optimal cut-off value, that of Vd was 0.708 with 58.97% sensitivity and 77.27% specificity when 17.19 cm/s was chosen as the optimal cut-off value, that of RI was 0.842 with 87.18% sensitivity and 66.67% specificity when 0.71 was chosen as the optimal cut-off value, and that of PI was 0.683 with 56.41% sensitivity and 78.79% specificity when 1.50 was chosen as the optimal cut-off value. Multivariate Logistic regression analysis showed that D≥4.91 mm, Vs≥71.19 cm/s and RI≥0.71 were associated with AKI in septic shock (P<0.05) . Patients with stage 3 AKI had lower D, and higher RI than those with stage 2 AKI (P<0.05) . Patients with stage 3 AKI had lower D, Vs and Vd, and higher RI than those with stage 1 AKI (P<0.05) . Patients with stage 2 AKI had lower Vd than those with stage I AKI (P<0.05) . Spearman rank analysis showed that both the D and Vd were strongly negatively correlated with the severity of AKI, and Vs was weakly negatively correlated with it (rs=-0.421, -0.674, -0.358, P<0.05) . RI was strongly positively correlated with the severity of AKI (rs=0.539, P<0.001) . PI was not significantly correlated with the severity of AKI (P>0.05) . Conclusion CDU could detect the changes of renal hemodynamics in patients with septic shock. Renal hemodynamic indices are related to the development and severity of AKI, which could be used as diagnostic markers or predictors of AKI in septic shock. So it may be possible to diagnose and predict AKI in septic shock by detecting renal hemodynamic indices.

Keywords

• shock|color doppler ultrasound|septic shock|renal hemodynamics|acute kidney injury|evaluation value|diagnosis|forecasting