Fluid Overload Modifies Hemodynamic Impact of CRRT: Evidence of a Covert Cardiorenal Syndrome?

Background: Fluid overload (FO) in critically ill children correlates with higher morbidity and mortality rates. Continuous renal replacement therapy (CRRT) is commonly employed to manage FO. In adults, both FO and CRRT adversely affect myocardial function. It remains unclear if children experience similar cardiovascular effects.

Methods: Observational single-center study on children (<18 years) receiving CRRT at Texas Children's Hospital from 11/2019 to 3/2021. Excluded were those with end-stage renal disease, pacemakers, extracorporeal membrane oxygenation, ventricular assist devices, apheresis, or without an arterial line. Electrocardiometry (ICON® Osypka Medical GmbH (Berlin, Germany)) which is non-invasive and utilizes bioimpedance, was applied to obtain hemodynamic data over the first 48 hours of CRRT. Our aim was to identify how FO >15% affects hemodynamics in children receiving CRRT.

Results: Seventeen children, median age 43 months (IQR 12-124), were included. The median FO at CRRT initiation was 14.4% (2.4%-25.6%), with 9 (53%) patients having FO >15%. Differences were noted in systemic vascular resistance index (1277 [IQR 1088-1666] vs. 1030 [IQR 868-1181] dyne*s/m2/cm5, P < 0.01), and cardiac index (3.90 [IQR 3.23-4.75] vs. 5.68 [IQR 4.65-6.32] L/min/m2, P < 0.01), with no differences in heart rate or mean arterial pressure between children with and without FO.

Conclusion: FO affects the hemodynamic profile of children on CRRT, with those having FO >15% showing higher SVRI and lower CI, despite HR and MAP remaining unchanged. Our study illustrates the feasibility and utility of electrocardiometry in these patients, suggesting future research employ this technology to further explore the hemodynamic effects of dialysis in children.