Lung ultrasound: a novel technique for detecting fluid overload in children on dialysis

Background: Optimizing the target weight of infants and children on dialysis remains an important clinical challenge. The use of ultrasound to detect fluid overload in adult patients on dialysis is receiving growing attention. We hypothesized that fluid overload can be quantified in infants and children receiving dialysis using lung ultrasound. Methods: In this prospective observational study, infants and children receiving dialysis for end-stage renal disease (ESRD) or acute kidney injury (AKI) in a regional paediatric nephrology centre were eligible. Lung ultrasound examinations were performed during in-centre dialysis, on home visits or in an outpatient clinic. Fluid overload was assessed by quantifying B-lines on ultrasound and compared with proportional (%) increase in patient weight from the target weight. Results: A total of 142 ultrasound assessments were performed in 23 children. In children with AKI, median B-line score reduced from 5 (range 0-22) at presentation to 1.5 (0-4) at recovery (P = 0.04) with concurrent improvement in fluid overload judged by weight from 7.2 (- 1.9 to 15.2)% to 0%. A linear correlation between lung ultrasound B-line score and fluid overload judged by weight was observed in children with AKI (r = 0.83) and ESRD (r = 0.61). Inter-observer variability was acceptable. Conclusions: Lung ultrasound is a practical and sensitive method of quantifying subclinical fluid overload in infants and children on dialysis. Interventional studies to determine the benefits of using lung ultrasound to optimize the target weight for children with ESRD are merited.