Definitions
SOS diagnosis and grading were based on the European Society for Blood and Marrow Transplantation (EBMT) Pediatric Criteria (8). AKI was defined and staged according to Kidney Disease Improving Global Outcomes (KDIGO) guidelines (9). AKI was classified as severe if it was stage 2 or 3 per KDIGO classification. Fluid overload was calculated according to the formula described by Goldstein et al.: FO % = Fluid in − fluid out (L) / intensive care admission body weight in kg × 100 (10). Cumulative fluid overload is the sum of daily FO % before or after CKRT. For example, cumulative FO D-3 = (FO% D-3 + FO%D-2 + FO% D-1). All patients were challenged with diuretics if they did not have adequate urine output after stopping CKRT. Successful liberation was defined as patients who did not require CKRT or other dialysis modality for at least 72 h after discontinuation of CKRT.