Incidence and outcome of acute kidney injury by the pRIFLE criteria for children receiving extracorporeal membrane oxygenation after heart surgery

BACKGROUND: Acute kidney injury (AKI) is common in patients treated with extracorporeal membrane oxygenation (ECMO). The RIFLE criteria demonstrate clinical relevance for diagnosing AKI and classifying its severity. OBJECTIVES: To systematically define the incidence, clinical course and outcome of AKI using the pediatric pRIFLE criteria. DESIGN: Retrospective, medical records review. SETTINGS: Pediatric cardiac surgical intensive care units at a tertiary care hospital in Riyadh. PATIENTS AND METHODS: We reviewed the records of all pediatric patients that underwent cardiac surgery and required ECMO postoperatively between 1 January 2011 and 1 January 2016. AKI was classified according to the pRIFLE criteria 48 hours after ECMO initiation. Demographics and concomitant therapies for all patients were collected. MAIN OUTCOME MEASURE(S): Outcome was assessed by recovery from AKI at time of discharge, ICU stay and mortality. RESULTS: Fifty-nine patients needed ECMO after cardiac surgery during the study period. Their mean (SD) age and weight was 11.0 (16.5) month and 5.5 (3.6) kg, respectively. All patients had a central venoarterial ECMO inserted. Fifty-three patients (90%) developed AKI after ECMO initiation. The majority of patients (57%) were categorized as pRIFLE-Failure, having a higher mortality rate (28/34 patients, 82%) in comparison to the pRIFLE-Injury and pRIFLE-Risk groups. Twenty-nine patients (49%) required either peritoneal dialysis (PD), or renal replacement therapy (RRT) or both. For AKI vs non-AKI patients, there was a statistically significant difference between mean (SD) ECMO duration (9.0 [8.00] vs 6.0 [2.0] days; P=.02) and ICU stay (37.0 [41.0] vs 21.0 [5.0] days; P=.03), respectively. The overall mortality rate was 58%, with a significant difference (P=.03) between AKI and non-AKI groups. All the patients who survived had normal creatinine clearance at hospital discharge. CONCLUSION: There is a high incidence of AKI in pediatric patients requiring ECMO after cardiac surgery, and it is associated with higher mortality, increased ECMO duration, and increased ventilator days. LIMITATIONS: Single-center retrospective analysis and the small sample size limited the precision of our estimates in sub-populations.