Predictors of acute kidney injury post-cardiopulmonary bypass in children.

OBJECTIVE: To investigate the incidence, implicating factors and outcome of acute kidney injury (AKI) after cardiopulmonary bypass (CPB) in patients admitted to a pediatric cardiothoracic intensive care unit (ICU). DESIGN: A retrospective review study. SETTING: A 10-bed cardiothoracic ICU. PATIENTS: One hundred and twenty-four children (<18 years of age) admitted to the cardiothoracic ICU following CPB between January 2007 and December 2009. METHODS: Age, sex, diagnosis, baseline and post-surgery hemoglobin, total leukocyte count, platelet count and biochemistry were recorded. Baseline and postoperative urea (mg/dl), creatinine (mg/dl), urine output (ml/kg/h) and inotrope dose were also recorded daily. The duration of CPB was noted. Postoperative cardiac, renal, hepatic, neurologic and respiratory dysfunctions were recorded. RESULTS: Seven (5%) children developed AKI stage I, five children (4%) developed AKI stage II and two children developed AKI stage III (2%). All patients with AKI had a longer stay in hospital and increased mortality. Two children required dialysis for AKI and none developed chronic renal impairment. All patients with AKI stage III died during the ICU stay. Using stepwise regression, younger age (<1 year), weight <10 kg, pump failure, sepsis and duration of CPB >90 min were significant risk factors identified for developing AKI. CONCLUSIONS: AKI is common and occurred in 11% of our patients following CPB; however, AKI requiring renal replacement therapy is uncommon.