Relationship between acute kidney injury and brain MRI findings in asphyxiated newborns after therapeutic hypothermia

Background: We hypothesized that acute kidney injury (AKI) in asphyxiated neonates treated with therapeutic hypothermia would be associated with hypoxic-ischemic lesions on brain magnetic resonance imaging (MRI). Methods: Medical records of 88 cooled neonates who had had brain MRI were reviewed. All neonates had serum creatinine assessed before the start of cooling; at 24, 48, and 72 h through cooling; and then on day 5 or 7 of life. A neonatal modification of the Kidney Disease: Improving Global Outcomes guidelines was used to classify AKI. MRI images were evaluated by a neuroradiologist masked to outcomes. Outcome of interest was abnormal brain MRI at 7-10 d of life. Results: AKI was found in 34 (39%) of 88 neonates, with 15, 7, and 12 fulfilling criteria for stages 1, 2, and 3, respectively. Brain MRI abnormalities related to hypoxia-ischemia were present in 50 (59%) newborns. Abnormal MRI was more frequent in infants from the AKI group (AKI: 25 of 34, 73% vs. no AKI: 25 of 54, 46%; P = 0.012; odds ratio (OR) = 3.2; 95% confidence interval (CI) = 1.3-8.2). Multivariate analysis identified AKI (OR = 2.9; 95% CI = 1.1-7.6) to be independently associated with the primary outcome. Conclusion: AKI is independently associated with the presence of hypoxic-ischemic lesions on postcooling brain MRI.