Continuous renal replacement therapy in children: fluid overload does not always predict mortality

Abstract

Background: Mortality among critically ill children requiring continuous renal replacement therapy (CRRT) is high. Several factors have been identified as outcome predictors. Many studies have specifically reported a positive association between the fluid overload at CRRT initiation and the mortality of critically ill pediatric patients.

Methods: This study is a retrospective single-center analysis including all patients admitted to the pediatric intensive care unit (PICU) of our hospital who received CRRT between 2000 and 2012. One hundred thirty-one patients were identified and subsequently classified according to primary disease. Survival rates, severity of illness and fluid balance differed among subgroups. The primary outcome was patient survival to PICU discharge.

Results: Overall survival to PICU discharge was 45.8 %. Based on multiple regression analysis, mortality was independently associated with onco-hematological disease [odds ratio (OR) 11.7, 95 % confidence interval (CI) 1.3-104.7; p = 0.028], severe multiple organ dysfunction syndrome (MODS) (OR 5.1, 95 % CI 1.7-15; p = 0.003) and hypotension (OR 11.6, 95 % CI 1.4-93.2; p = 0.021). In the subgroup analysis, a fluid overload (FO) of more than 10 % (FO>10 %) at the beginning of CRRT seems to be a negative predictor of mortality (OR 10.9, 95 % CI 0.78-152.62; p = 0.07) only in children with milder disease (renal patients). Due to lack of statistical power, the independent effect of fluid overload on mortality could not be analyzed in all subgroups of patients.

Conclusions: In children treated with CRRT the underlying diagnosis and severity of illness are independent risk factors for mortality. The degree of FO is a negative predictor only in patients with milder disease.

Keywords: Acute renal failure; CRRT; Fluid overload; Multiple organ dysfunction syndrome; Survival; Underlying diseases.