201: Epidemiology of Acute Kidney Injury Following Cardiopulmonary Bypass in Pediatric Cardiac Surgery Patients

Abstract

Background: Acute kidney injury (AKI) is an important complication following cardiopulmonary bypass in pediatric cardiac surgery patients. However, its prevalence is highly variable in studies depending on the choice of AKI definition. Objectives: Therefore, we aim to describe the epidemiology and outcome associated with AKI according to the accepted pediatric Risk Injury Failure Loss End-stage renal disease criteria (pRIFLE) in our postoperative population of pediatric cardiac surgery patients. Design/Methods: Patients from zero to 18 years of age admitted to our PICU after cardiac surgery with cardiopulmonary bypass between May 2009 and May 2011 were included in this retrospective cohort study. Data were abstracted from the medical records and independently validated by two observers. Exclusion criteria were death during surgery, preoperative chronic kidney failure and prior heart transplant. Patients were classified according to the pRIFLE categories of risk, injury and failure before comparing their outcomes. Descriptive analyses were based on one-way analysis of variance F-test with correction for unequality of variances when appropriate. Results: Of the 141 patients who met the inclusion criteria, 59 met the pRIFLE definition for AKI, representing a prevalence rate of 42%. Compared to the non-AKI group, AKI patients were younger (median 0.5 [IQR 0.01 to 1.41] vs 1.8 [IQR 0.72 to 8.07] years; P<0.0001), had higher Pediatric Risk of Mortality (PRISM) scores (median 10 [IQR 8 to 13] vs 8 [IQR 6 to 10]; P<0.05), higher maximal serum creatinine levels (mean 56 mumol/L [95% CI 48 mumol/L to 63 mumol/L] vs 37 mumol/L [95% CI 33 mumol/L to 40 mumol/L]; P<0.0001), longer intensive care unit length of stay (mean 129 h [95% CI 95 h to 163 h] vs 58 h [95% CI 40 h to 75 h]; P<0.05), longer mechanical ventilation duration (mean 57 h [95% CI 26 h to 89 h] vs 21 h [95% CI 5 h to 37 h]; P<0.05) and longer duration of cardiopulmonary bypass (mean 142 min [95% CI 125 min to 159 min] vs 95 min [95% CI 85 min to 106 min]; P>0.05). One patient in each group died. Conclusions: AKI is highly prevalent following cardiopulmonary bypass in pediatric cardiac surgery. Increasing severity of AKI is associated with longer duration of cardiopulmonary bypass, longer intensive care unit length of stay and duration of mechanical ventilation. Specific modifiable risk factors and therapeutic approaches for AKI still need to be identified in order to prevent and treat AKI in this specific population.