Effectiveness and feasibility of continuous renal replacement therapy for acute kidney injury in neonates weighing 3 kg or less: a two-centre, retrospective study.

Background: Continuous renal replacement therapy (CRRT) is commonly used for the treatment of acute kidney injury (AKI) in critically ill neonates. This study investigated the effectiveness and feasibility of CRRT for AKI in neonates who weigh ≤3 kg.

Methods: Data from 19 neonates with a weight ≤3 kg and AKI who underwent CRRT at two centres between January 2015 and October 2021 were collected retrospectively. Kidney function, circulatory function, complications and clinical outcomes were recorded. Repeated-measures analyses of variance, t-tests and non-parametric tests were conducted.

Results: The median patient age at CRRT initiation was 3 days (IQR: 1-7 days). The median patient weight at CRRT initiation was 2.67 kg (IQR: 2.20-2.85 kg). The median CCRT duration was 46 hours (IQR: 32-72 hours). The serum creatinine and blood urea nitrogen levels decreased significantly, and the mean arterial pressure increased significantly after 12 hours of CRRT and at the end of CRRT. The urinary output was significantly increased at the end of CRRT. 11 patients had thrombocytopaenia, 6 had electrolyte disorders and 3 had blocked tubes. Five patients were discharged, six died after their parents chose to discontinue treatment and eight died after active treatment. Weight at CRRT initiation and urinary output at the end of CRRT were significantly lower among patients who died than among patients who survived.

Conclusions: CRRT is feasible and effective for AKI in neonates who weigh ≤3 kg when accompanied by elaborate supportive care. Lower body weight and persistent oliguria may be correlated with an increased risk of poor clinical outcomes.