Clinical Study On The Evaluation Of Renal Microcirculation By Contrast-enhanced Ultrasound In Patients With Septic Shock

Purpose: Hypoperfusion at microcirculation level plays an important role in septic shock.The purpose of this study was to explore the clinical value of CEUS in evaluating renal microcirculation in septic shock.Methods: The septic shock patients admitted to intensive care unit of zhongda hospital affiliated to southeast university from January 2018 to December 2019 were enrolled.Patients were completed the 1-hour Bundle treatment.General information of the patients was collected,hemodynamic and renal function indexes were measured.Renal CEUS was performed on day 0 and day 1 respectively,CEUS parameters were observed and recorded including PI、TTP、RBV and MTT.Meanwhile,the renal interlobar arterial resistance index(RI)was measured by doppler ultrasound.Patients were divided into AKI group and non-AKI group according to Kidney Disease: Improving Global Outcomes(KDIGO)-AKI diagnostic criteria,and the parameters differences were compared between the two groups.The diagnostic value of renal CEUS parameters in septic shock AKI was analyzed by ROC.Pearson correlation analysis was used to analyze the correlation between CEUS parameters and other parameters.Results: 40 patients were enrolled,20 were admitted to AKI group and 20 were admitted to non-AKI group.MAP in patients with septic shock reached the target level(MAP>65mm Hg)and the cardiac output were normal.The values of PI,RBV and MTT in the AKI group were decreased compared with those in the non-AKI group,However,the interlobar arterial resistance index was higher than that of the non-AKI group.(PI(%): 45.95±8.18 vs57.98±4.27,RBV:3594.33±1256.49 vs 5582.82±1262.10,MTT:56.22±10.24 vs71.13±13.88,RI: 0.75±0.06 vs0.64±0.07,p<0.05).ROC curve showed that the area under the curve(AUC)of PI,RBV,MTT and RI in the diagnosis of septic shock AKI was 0.92,0.86,0.82 and 0.81 respectively(p<0.05).The optimal cut-off values were50.05%,4858.37,60.76 s,0.74 respectively.MTT was significantly lower in the non-surviving group(group effect p = 0.046)and MTT reduced over time in the non-surviving group(interaction group×time p = 0.002).The correlation analysis showed that PI is moderately or weakly correlated with CVP,Lac and Scr,RBV was weakly correlated with CVP and Scr,MTT was moderately correlated with RI and Scr.(both P < 0.05).Conclusion: Macrohemodynamic and microhemodynamic are not consistent,renal cortical perfusion may still be at a low level when macrohemodynamic is restored.Contrast-enhanced ultrasound(CEUS)can realize real-time,dynamic and quantitative evaluation of renal blood perfusion,which has independent diagnostic value for septic shock AKI.MTT may be useful in predicting the outcome of patients with septic shock AKI.MTT may provide more information on renal hemodynamics.Contrast-enhanced ultrasound(CEUS)is expected to be a useful tool for evaluating renal perfusion in patients with septic shock.