Fluid Overload and Kidney Injury Score: A Multidimensional Real-Time Assessment of Renal Disease Burden in the Critically Ill Patient.

OBJECTIVE: Interruptive acute kidney injury alerts are reported to decrease acute kidney injury-related mortality in adults. Critically ill children have multiple acute kidney injury risk factors; although recognition has improved due to standardized definitions, subtle changes in serum creatinine make acute kidney injury recognition challenging. Age and body habitus variability prevent a uniform maximum threshold of creatinine. Exposure of nephrotoxic medications is common but not accounted for in kidney injury scores. Current severity of illness measures do not include fluid overload, a well-described mortality risk factor. We hypothesized that a multidimensional measure of renal status would better characterize renal severity of illness while maintaining or improving on correlation measures with adverse outcomes, when compared with traditional acute kidney injury staging. DESIGN: A novel, real-time, multidimensional, renal status measure, combining acute kidney injury, fluid overload greater than or equal to 15%, and nephrotoxin exposure, was developed (Fluid Overload Kidney Injury Score) and prospectively applied to all patient encounters. Peak Fluid Overload Kidney Injury Score values prior to discharge or death were used to measure correlation with outcomes. SETTING: Quarternary PICU of a freestanding children's hospital. PATIENTS: All patients admitted over 18 months. INTERVENTION: None. RESULTS: Peak Fluid Overload Kidney Injury Score ranged between 0 and 14 in 2,830 PICU patients (median age, 5.5 yr; interquartile range, 1.3-12.9; 55% male), 66% of patients had Fluid Overload Kidney Injury Score greater than or equal to 1. Fluid Overload Kidney Injury Score was independently associated with PICU mortality and PICU and hospital length of stay when controlled for age, Pediatric Risk of Mortality-3, ventilator, pressor, and renal replacement therapy use (p = 0.047). Mortality increased from 1.5% in Fluid Overload Kidney Injury Score 0 to 40% in Fluid Overload Kidney Injury Score 8+. When urine output points were excluded, Fluid Overload Kidney Injury Score was more strongly correlated with mortality than fluid overload or acute kidney injury definitions alone. CONCLUSION: A multidimensional score of renal disease burden was significantly associated with adverse PICU outcomes. Further studies will evaluate Fluid Overload Kidney Injury Score as a warning and decision support tool to impact patient-centered outcomes.

Acute Kidney Injury in Pediatric Heart Failure.

Acute kidney injury (AKI) is very common in pediatric medical and surgical cardiac patients. Not only is it an independent risk factor for increased morbidity and mortality in the short run, but repeated episodes of AKI lead to chronic kidney disease (CKD) especially in the most vulnerable hosts with multiple risk factors, such as heart transplant recipients. The cardiorenal syndrome, a term coined to emphasize the bidirectional nature of simultaneous or sequential cardiac-renal dysfunction both in acute and chronic settings, has been recently described in adults but scarcely reported in children. Despite the common occurrence and clinical and financial impact, AKI in pediatric heart failure outside of cardiac surgery populations remains poorly studied and there are no large-scale pediatric specific preventive or therapeutic studies to date. This article will review pediatric aspects of the cardiorenal syndrome in terms of pathophysiology, clinical impact and treatment options.