Fluid Overload Is Associated With Higher Mortality and Morbidity in Pediatric Patients Undergoing Cardiac Surgery* :

Introduction Despite significant improvements in intensive care medicine, the prognosis of acute renal failure (ARF) remains poor, with mortality ranging from 40% to 65%. The aim of the present observational study was to analyze the influence of patient characteristics and fluid balance on the outcome of ARF in intensive care unit (ICU) patients. Methods The data were extracted from the Sepsis Occurrence in Acutely Ill Patients (SOAP) study, a multicenter observational cohort study to which 198 ICUs from 24 European countries contributed. All adult patients admitted to a participating ICU between 1 and 15 May 2002, except those admitted for uncomplicated postoperative surveillance, were eligible for the study. For the purposes of this substudy, patients were divided into two groups according to whether they had ARF. The groups were compared with respect to patient characteristics, fluid balance, and outcome. Results Of the 3,147 patients included in the SOAP study, 1,120 (36%) had ARF at some point during their ICU stay. Sixty-day mortality rates were 36% in patients with ARF and 16% in patients without ARF (P < 0.01). Oliguric patients and patients treated with renal replacement therapy (RRT) had higher 60-day mortality rates than patients without oliguria or the need for RRT (41% versus 33% and 52% versus 32%, respectively; P < 0.01). Independent risk factors for 60-day mortality in the patients with ARF were age, Simplified Acute Physiology Score II (SAPS II), heart failure, liver cirrhosis, medical admission, mean fluid balance, and need for mechanical ventilation. Among patients treated with RRT, length of stay and mortality were lower when RRT was started early in the course of the ICU stay. Conclusion In this large European multicenter study, a positive fluid balance was an important factor associated with increased 60-day mortality. Outcome among patients treated with RRT was better when RRT was started early in the course of the ICU stay.

Critically ill children with hemodynamic instability and acute kidney injury often develop fluid overload. Continuous renal replacement therapy (CRRT) has emerged as a favored modality in the management of such children. This study investigated the association between fluid overload and mortality in children receiving CRRT. Prospective observational study. 297 children from 13 centers across the United States participating in the Prospective Pediatric CRRT Registry. Fluid overload from intensive care unit (ICU) admission to CRRT initiation, defined as a percentage equal to (fluid in [L] - fluid out [L])/(ICU admit weight [kg]) x 100%. The primary outcome was survival to pediatric ICU discharge. Data were collected regarding demographics, CRRT parameters, underlying disease process, and severity of illness. 153 patients (51.5%) developed or = 20% fluid overload. Patients who developed > or = 20% fluid overload at CRRT initiation had significantly higher mortality (61/93; 65.6%) than those who had 10%-20% fluid overload (22/51; 43.1%) and those with or = 20% and or = 20% fluid overload had an adjusted mortality OR of 8.5 (95% CI, 2.8-25.7). This was an observational study; interventions were not standardized. The relationship between fluid overload and mortality remains an association without definitive evidence of causality. Critically ill children who develop greater fluid overload before initiation of CRRT experience higher mortality than those with less fluid overload. Further goal-directed research is required to accurately define optimal fluid overload thresholds for initiation of CRRT. Copyright 2010 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Continuous venovenous hemofiltration (CVVH) alone or with dialysis (D) has become an important supportive therapy for critically ill children with acute renal failure. Previous reports of pediatric patient outcome either mix CVVH/D with other renal replacement modalities or do not examine severity of illness. The current study examines only outcomes of children receiving CVVH/D using Pediatric Risk of Mortality (PRISM) scores to control for severity of illness. Twenty-one patients (mean age: 8.8 +/- 6.3 years; mean weight: 28.3 +/- 20.8 kg) received 22 courses of CVVH/D. Nine (42.8%) of 21 patients survived. Nine (75%) of 12 deaths occurred within 25 days of pediatric intensive care unit (PICU) admission. Mean PRISM score at PICU admission and CVVH initiation were 13.1 +/- 5.8 and 15.4 +/- 8.9, respectively. Mean patient weight, age, PRISM score at PICU admission and at CVVH/D initiation, maximum pressor number, estimated glomerular filtration rate at CVVH/D initiation and change in mean airway pressure did not differ between survivors and nonsurvivors. The degree of fluid overload at CVVH/D initiation was significantly lower in survivors (16.4% +/- 13.8%) compared with nonsurvivors (34.0% +/- 21.0%), even when controlled for severity of illness by PRISM score. Mean cost of providing CVVH/D accounted for only 1% of total PICU cost per patient. The pattern of early multiorgan system failure and death, minimal relative cost of CVVH/D provision, and potential for improved outcome with initiation of CVVH/D at lesser degrees of fluid overload are factors that may support early initiation of CVVH/D in critically ill children with acute renal failure.