Incidence and risk factors associated with acute kidney injury in newborns receiving therapeutic hypothermia

Abstract

Background: To evaluate the incidence and potential predisposing factors for the development of acute kidney injury (AKI) in asphyxiated neonates undergoing hypothermic treatment.

Methods: This retrospective study was conducted at the Fondazione IRCCS San Gerardo dei Tintori, Monza, Italy. All neonates above 34 weeks of gestation diagnosed with hypoxic-ischemic encephalopathy (HIE) and treated with hypothermia, weighing more than 1800 g, admitted from January 1, 2013 to December 31, 2022, were included. AKI was defined according to the neonatal KDIGO classification.

Results: A total of 75 neonates were enrolled, including 13 (17%) with severe HIE. The incidence of AKI was 35%, with 62% of cases identified as a reduction in diuresis, 27% as changes in creatinine and oliguria, and only 11% as isolated creatinine elevation. The rate of AKI was significantly higher in infants with severe HIE (p < 0.001). The development of AKI added significantly (aOR = 41.2, p = 0.007) to the probability of death, even after adjusting for severe HIE. Infants who developed AKI required more inotropes, had higher rates of hyponatremia (serum sodium < 125 mEq/L), and were less likely to normalize lactate levels within 24 h of birth.

Conclusions: In asphyxiated newborns, reduced kidney perfusion can cause kidney impairment in nearly 40% of those undergoing treatment. Enhancing the detection of AKI is crucial for improving patient outcomes. We recommend proactive monitoring of lactate trends, urinary output, and serum sodium levels to enable early interventions that protect kidney function and improve outcomes for these vulnerable infants.

Keywords: AKI; Acute kidney injury; Newborn; Perinatal asphyxia.