Circuit life span in critically ill children on continuous renal replacement.

Abstract

Reconociendo la necesidad de optimizar la terapia y minimizar las complicaciones, el estudio se propuso identificar los factores que influyen en la duración del circuito de CRRT en niños. A través de un diseño observacional prospectivo, se analizaron datos de un amplio número de pacientes, permitiendo un análisis riguroso de múltiples variables. Los resultados del estudio aportaron valiosos hallazgos, demostrando que la hemodiafiltración, el aumento de la dosis de heparina, el uso de filtros con mayor superficie y niveles iniciales de creatinina más bajos se asocian con una mayor duración del circuito.

Introduction: One of the greatest problems with continuous renal replacement therapy (CRRT) is early coagulation of the filters. Few studies have monitored circuit function prospectively. The purpose of this study was to determine the variables associated with circuit life in critically ill children with CRRT.

Methods: A prospective observational study was performed in 122 children treated with CRRT in a pediatric intensive care unit from 1996 to 2006. Patient and filter characteristics were analyzed to determine their influence on circuit life. Data were collected on 540 filters in 122 patients and an analysis was performed of the 365 filters (67.6%) that were changed due to circuit coagulation.

Results: The median circuit life was 31 hours (range 1 to 293 hours). A univariate and multivariate logistic regression study was performed to assess the influence of each one of the factors on circuit life span. No significant differences in filter life were found according to age, weight, diagnoses, pump, site of venous access, blood flow rate, ultrafiltration rate, inotropic drug support, or patient outcome. The mean circuit life span was longer when the heparin dose was greater than 20 U/kg per hour (39 versus 29.1 hours; P = 0.008), with hemodiafiltration compared with hemofiltration (34 versus 22.7 hours; P = 0.001), with filters with surface areas of 0.4 to 0.9 m2 (38.2 versus 26.1 hours; P = 0.01), and with a catheter size of 6.5 French or greater (33.0 versus 25.0 hours; P = 0.04). In the multivariate analysis, hemodiafiltration, heparin dose of greater than 20 U/kg per hour, filter surface area of 0.4 m2 or greater, and initial creatinine of less than 2 mg/dL were associated with a filter life of more than 24 and 48 hours. Total effluent rate of greater than 35 mL/kg per hour was associated only with a filter life of more than 24 hours.

Conclusion: Circuit life span in CRRT in children is short but may be increased by the use of hemodiafiltration, higher heparin doses, and filters with a high surface area.