The use of continuous renal replacement therapy in critically ill patients with COVID-19-related acute kidney injury

Background/Aim. Patients with severe clinical COVID-19 are at higher risk of developing acute kidney injury (AKI). The aim of the study was to analyze the risk factors for AKI/AKI on chronic kidney disease (CKD) and the results of treatment using continuous renal replacement therapy (CRRT) in critically ill COVID-19 patients. Methods. The study included 101 COVID-19 patients with AKI treated with CRRT out of a total of 293 patients with AKI. The study was conducted from March 2020 to July 2021 at the University Clinical Center of Vojvodina, Serbia. Results. The average age of patients was 64.69 +/- 9.71 years. Out of the total number of patients, 82.2% were male, of whom 75.2% suffered from hypertension. On invasive mechanical ventilation (IMV) were 93.7% of patients, and 92.1% were on vasopressor therapy. The average length of IMV until the beginning of CRRT was 4.65 +/- 4.57 days. In the first 24 hrs after starting IMV, 60% of patients had to undergo CRRT. Before administering CRRT, the average Simplified Acute Physiology Score II was 39.13 +/- 14.45, creatinine 312 mu mol/L [Interquartile Range (IQR) 208.0-437.5], procalcitonin 2.70 ng/L (IQR 0.62-7.20), while 10.9% of patients had SpO(2)/FiO(2) index > 200 and 41.6% had anuria. The mean number of procedures was 2.01 +/- 1.36. The most frequent modality was hemodiafiltration in 67.3% of patients, and 46% used the oXiris (R) membrane. Using binary logistic regression, including demographic parameters, comorbidities, as well as clinical parameters before CRRT, it was found that patients with previous kidney disease were 3.43 times more susceptible to developing AKI, and patients with SpO(2)/FiO(2) index >= 200 were 69% less susceptible to developing AKI/AKI on CKD requiring CRRT in the first 24 hrs from the start of IMV. Conclusion. Determining the risk factors for AKI/AKI on CKD is important for planning the prevention of these conditions that require the application of CRRT with the correct choice of dialysis modality and dose, membrane/filter type, and anticoagulant dose.