Alterations Of Renal Microcirculation In Sepsis: An Observational Study

Objective:To observe the alterations of renal microcirculation during sepsis,and to explore the correlation between the occurrence of septic acute kidney injury（AKI）and the alterations of renal microcirculation.Method:Sepsis patients admitted to the intensive care unit（ICU）of the fourth hospital of hebei medical university from November 2018 to January2019 were in our research.All patients completed initial resuscitation within1h after admission to ICU.According to KDIGO guideline,based on whether or not a AKI occurs within 24 hours,it is divided into AKI group and non-AKI group.Within the first 24 hours after ICU,the kidney of the patient were measured through the two-dimensional gray scale ultrasound and contrast-enhanced ultrasound（CEUS）.The relevant parameters were measured and recorded,to quantitatively analyze the blood flow perfusion of the renal cortex and the medulla.At the same time,system hemodynamic parameters,white bloodcellcount,neutrophilcount,C-reactiveproteinand procalcitonin,serum creatinine,creatinine clearance rate and urine volume per hour were detected and recorded.The differences of each index between the two groups were compared.Results:Eventually 29 patients were included in this study,including 22males and 7 females with mean age of（62±15）years old.There were 18patients in AKI group,11 patients in non-AKI group.Between AKI group and non-AKI group,heart rate（HR）,cardiac index（CI）,mean arterial pressure（MAP）,peripheral vascular resistance index（SVRI）,central veno-arterial pressure of carbon dioxide difference（Pcv-aCO₂）,central venous oxygen saturation（ScvO₂）,PDU score,renal resistance index（RRI）were no significant difference（P>0.05）.In AKI group,CVP,vasoactive drug dosage,blood lactate were higher than those in non-AKI group,and the differences were statistically significant（P<0.05）.In AKI group,renal cortical wash in slope（WIS）was lower than that in the non-aki group,rise time（RT）was greater than that in non-aki group,and renal medulla WIS was lower than that in non-aki group,with statistically significant differences（P<0.05）.According to further analysis by receiver operating characteristic（ROC）curve,The cutoff value of WIS was equal or more than 21.47 for predicting occurrence of AKI with an area under the ROC curve（AUC）,sensitivity,and specificity of 0.823,72.73%and 88.89%,respectively.There was no significant difference in peak intensity（PI）,mean transit time（MTT）and AUC between the two groups（P>0.05）.Meanwhile,compared with the non-AKI group,white blood cell count,neutrophil count,C-reactive protein and procalcitonin of AKI group were significantly increased,with statistically significant differences（P<0.05）.Conclusions:The study found that contrast-enhanced ultrasound is significant technique to evaluate renal microcirculation in patients with sepsis.WIS is a good parameter to predict the occurrence of AKI in patients with sepsis after resuscitation.The occurrence of AKI in patients with sepsis is correlated with alterations of renal cortical and medullary perfusion.