Jennifer G. Jetton

In recent years, there have been significant advancements in our understanding of acute kidney injury (AKI) and its impact on outcomes across medicine. Research based on single-center cohorts suggests that neonatal AKI is very common and associated with poor outcomes. In this state-of-the-art review on neonatal AKI, we highlight the unique aspects of neonatal renal physiology, definition, risk factors, epidemiology, outcomes, evaluation, and management of AKI in neonates. The changes in renal function with gestational and chronologic age are described. We put forth and describe the neonatal modified Kidney Diseases: Improving Global Outcomes AKI criteria and provide the rationale for its use as the standardized definition of neonatal AKI. We discuss risk factors for neonatal AKI and suggest which patient populations may warrant closer surveillance, including neonates <1500 g, infants who experience perinatal asphyxia, near term/ term infants with low Apgar scores, those treated with extracorporeal membrane oxygenation, and those requiring cardiac surgery. We provide recommendations for the evaluation and treatment of these patients, including medications and renal replacement therapies. We discuss the need for long-term follow-up of neonates with AKI to identify those children who will go on to develop chronic kidney disease. This review highlights the deficits in our understanding of neonatal AKI that require further investigation. In an effort to begin to address these needs, the Neonatal Kidney Collaborative was formed in 2014 with the goal of better understanding neonatal AKI, beginning to answer critical questions, and improving outcomes in these vulnerable populations.

PURPOSE OF REVIEW: Acute kidney injury (AKI) is associated with increased risk of morbidity and mortality in critically ill children and adults. Neonates remain an understudied group, although previous evidence suggests that this association holds true for them as well. RECENT FINDINGS: Attention to the issue of neonatal AKI is increasing. New studies in very low-birthweight infants, infants with congenital heart disease who undergo cardiopulmonary bypass, those who receive extracorporeal membrane oxygenation and infants with perinatal depression continue to demonstrate that AKI is common in neonates and associated with increased risk of morbidity and mortality. Additional advances in the field of neonatal AKI include adaptation of modern, categorical AKI definitions, as well as further evaluation of novel urinary biomarkers (e.g., neutrophil gelatinase-associated lipocalin) in this patient group. SUMMARY: AKI is an independent risk factor for poor outcomes in critically ill neonates. Our ability to improve outcomes for these patients depends on heightened awareness of this issue both at the bedside as well as in research, commitment to using standardized AKI definitions in order to pool and compare data more effectively and improvement in our diagnostic methods with better AKI biomarkers so that we can identify AKI and intervene much earlier in the disease course.