Acute kidney injury in congenital diaphragmatic hernia requiring extracorporeal life support: an insidious problem

Patients with congenital diaphragmatic hernia (CDH) requiring extracorporeal life support (ECLS) are at increased risk for acute kidney injury (AKI). We hypothesized that AKI would be associated with increased mortality. We further hypothesized that vasopressor requirement, nephrotoxic medications, and infections would be associated with AKI.

We performed a retrospective chart review in all patients with CDH requiring ECLS from 1999 to 2009 (n = 68). Patient variables that could potentiate renal failure were collected. We used a rise in creatinine from baseline by the RIFLE (risk, 1.5×; injury, 2×; failure, 3×; loss; and end-stage renal disease) criteria to define AKI. Statistical analysis was performed via SPSS (SPSS, Chicago, IL) using Student t test and χ(2) analysis, with P < .05 being considered significant.

Survival to hospital discharge was 37 (54.4%) of 68. Acute kidney injury was identified in 48 (71%) of 68 patients, with 15 (22% of all patients) qualifying as injury and 33 (49% of all patients) qualifying as failure by the RIFLE criteria. Patients who qualified as failure by the RIFLE criteria had a significant decrease in survival (27.3% with failure vs 80% without failure; P = .001). Patients who qualified as failure also had increased length of ECLS (314 ± 145 vs 197 ± 115 hours; P = .001) and decreased ventilator-free days in the first 60 days (1.39 ± 5.3 vs 20.17 ± 17.4 days; P = .001). There was no significant difference in survival when patients qualified as risk or injury.

This is the first report using a systematic definition of AKI in patients with CDH on ECLS. There is a high incidence of AKI in these patients, and when it progresses to failure, it is associated with higher mortality, increased ECLS duration, and increased ventilator days. This highlights the importance of recognizing AKI in patients with CDH requiring ECLS and the potential benefit of preventing progression of AKI or early intervention.