The Infant KIdney Dialysis and Utrafiltration (I-KID) Study: A Stepped-Wedge Cluster-Randomized Study in Infants, Comparing Peritoneal Dialysis, Continuous Venovenous Hemofiltration, and Newcastle Infant Dialysis Ultrafiltration System, a Novel Infant Hemodialysis Device

Renal replacement therapy (RRT) for infants weighing less than 8 kg is technically challenging due to the lack of specialized equipment. Current options, such as peritoneal dialysis (PD) and continuous venovenous hemofiltration (CVVH), often struggle with fluid balance precision or are not specifically designed for such small patients. The I-KID study evaluated the Newcastle Infant Dialysis Ultrafiltration System (NIDUS), a novel device designed specifically for infants in this weight range, to determine its efficacy, safety, and precision in fluid removal.

The researchers conducted a nonblinded, cluster-randomized, stepped-wedge trial across six pediatric intensive care units (PICUs) in the U.K. The study compared the NIDUS device against standard-of-care RRT (PD or CVVH). The primary outcome was the precision of ultrafiltration (UF)—the ability of the device to remove fluid at the exact rate prescribed by clinicians. Secondary outcomes included biochemical clearance (creatinine, urea, and phosphate), safety profiles, and clinical outcomes.

The study found that the NIDUS device achieved significantly higher precision in ultrafiltration compared to the control group (PD and CVVH). Specifically, the variability between the prescribed and actual fluid removal rates was much lower with NIDUS. Regarding biochemical clearance, NIDUS performed better than PD but was less effective than the larger, higher-flow CVVH systems. While adverse events occurred across all groups, the NIDUS device demonstrated an acceptable safety profile for this critically ill population. The study also highlighted that NIDUS circuits did not require blood priming, unlike many CVVH circuits, which is a significant advantage for small infants.

This study provides evidence that NIDUS is a viable, effective alternative for RRT in infants under 8 kg. By offering more accurate fluid control, it may help mitigate the hemodynamic instability often associated with traditional RRT methods in small babies. While further refinements to the device's consumables are needed to improve usability, NIDUS represents a promising technological advancement for neonatal and infant critical care.