Renal Sonographic Indices as Predictive Markers for Acute Kidney Injury in Critical Care Patients: A Case Study of COVID-19 Patients

Abstract

Introduction: Preliminary studies have shown that up to 30% of covid-19 patients hospitalized have acute kidney injury (AKI). This study investigates the predictive potential of renal sonographic indices, including renal arterial resistive index (RRI) and pulsatility index (PI), as prognostic markers for AKI. Methods: The cohort study was conducted from September 2021 to April 2022, involving 140 COVID-19 patients admitted to the intensive care unit (ICU). Patients were followed for 6 months during hospitalization to monitor hourly urine output and daily serum creatinine levels for AKI incidence determination. Renal sonographic indices, including RRI and PI, were measured in both kidneys using color-doppler ultrasound upon ICU admission. Patients were divided into case (RRI ≥ 0.7 in at least one kidney) and control (RRI < 0.7 in both kidneys) groups. Multivariate logistic regression analysis examined RRI and PI as predictors for AKI, considering other risk factors. Results: Patients at case group (RRI ≥ 0.7) had substantially higher odds of developing AKI compared to control group (OR = 34.91, p < 0.001). For each unit increase in the mean of kidneys' PI (left/right), the odds of developing AKI decreased significantly (OR = 0.16, p < 0.001). The other factors, including sex, age group, diabetes, hypertension, and smoking status, did not show statistically significant associations with AKI (p-values > 0.05). Conclusions: the results highlight the importance of RRI and PI as non-invasive and valuable indicators for predicting the development of AKI in COVID-19 patients. Monitoring these renal sonographic indices could aid in the early identification and management of kidney-related complications in critically ill patients.