Plasma expansion and renal perfusion in critical COVID-19 with AKI

ABSTRACT

Introduction: We have previously described decreased renal perfusion in acute kidney injury (AKI) due to critical COVID-19 [1]. The objective of this study was to compare the effects of plasma expansion with a standardized fluid bolus on renal perfusion in patients with AKI compared to similar patients without AKI. Method(s) A case control study design was used to investigate group differences before and after a standardized intervention. ICU-treated COVID-19 patients without underlying kidney disease were assigned to two groups based on KDIGO Creatinine criteria for AKI. Renal perfusion was assessed by magnetic resonance imaging using phase contrast and arterial spin labeling before and directly after plasma expansion with 7.5 ml/kg Ringer's Acetate (Baxter). Mean arterial pressure (MAP) was recorded before plasma infusion and compared with maximum value after. Data was analyzed with a mixed model repeated measures ANOVA for all kidneys using a random effect to account for research subjects. Result(s) Nine patients with AKI and eight without were included in the study. Patients in both groups were of similar mean age and weight, 66 (SD 8) years and 94 (SD 22) kg in AKI group and 64 (SD 15) years and 93 (SD 20) kg in patients without AKI. The response to plasma expansion was similar with increased MAP by 18 (CI 8-28) mmHg and 20 (CI 10-31) mmHg respectively (Table 1). Total renal perfusion and cortical perfusion was not significantly changed by plasma expansion, however there was a reduction of medullary perfusion in patients without AKI (Table 1). Conclusion(s) Plasma expansion with a standardized fluid bolus did not increase renal perfusion in critically ill patients with ARDS due to COVID-19.