Extracorporeal carbon dioxide removal integrated into continuous renal replacement therapy in pediatric patients with ARDS: a retrospective single-center case series.

BACKGROUND: Extracorporeal carbon dioxide removal (ECCO₂R) may facilitate lung-protective ventilation in children with pediatric acute respiratory distress syndrome (PARDS), but pediatric experience remains limited. We aimed to descriptively characterize the clinical use, physiological changes, technical implementation, and observed complications of ECCO₂R integrated into continuous renal replacement therapy (CRRT) in pediatric patients with PARDS and acute kidney injury (AKI). METHODS: We conducted a retrospective, uncontrolled, single-center case series of pediatric patients with PARDS and AKI who received ECCO₂R integrated into an already indicated CRRT circuit between November 2023 and November 2025. To avoid non-independence of repeated observations, the first treatment episode per patient was included in the principal analysis (n = 7). Predefined physiological outcomes were assessed longitudinally at predefined time points. Longitudinal changes were analyzed using Friedman tests. Safety-related laboratory parameters were analyzed using Wilcoxon matched-pairs signed-rank tests. RESULTS: Median age was 12 years (interquartile range [IQR] 6-14 years). ECCO₂R was delivered at a median blood flow of 270 mL/min (IQR 100-300), corresponding to 9% (IQR 6-20%) of the estimated cardiac output. Friedman analysis demonstrated significant longitudinal improvements in all predefined principal physiological outcomes, including arterial carbon dioxide tension (PaCO₂), peak inspiratory pressure (PIP), driving pressure (ΔP), and tidal volume (Vt) (all P < 0.05). Median absolute changes from baseline to 24 h were - 10 mmHg (IQR - 27 to - 3) for PaCO₂, - 11 mbar (IQR - 14 to - 4) for PIP, - 9 mbar (IQR - 18 to - 6) for ΔP, and - 1.6 mL/kg (IQR - 3.6 to - 0.3) for Vt. Four patients were successfully weaned from ECCO₂R. No predefined major bleeding, clinically apparent hemolysis, thromboembolic complications, or device-related infections attributable to ECCO₂R-CRRT were identified; circuit clotting requiring circuit exchange occurred in two patients. CONCLUSIONS: Integration of ECCO₂R into an already indicated CRRT circuit was technically feasible and temporally associated with reductions in PaCO₂ and ventilatory pressures in this cohort. Although these descriptive findings should be regarded as hypothesis-generating rather than evidence of treatment efficacy or device safety, they suggest that integrated ECCO₂R-CRRT may represent a pragmatic adjunctive support strategy in carefully selected pediatric patients requiring CRRT. Prospective multicenter studies are needed to better define patient selection, anticoagulation strategies, weaning protocols, and the role of integrated ECCO₂R-CRRT within pediatric extracorporeal respiratory support. TRIAL REGISTRATION: German Clinical Trials Register (DRKS), DRKS00038799; retrospectively registered on April 23, 2026. https://drks.de/search/en/trial/DRKS00038799/details .