Acute Kidney Injury in Asphyxiated Newborn Infants with Cooling Therapy

Background: In the past, studies have reported variable incidence of acute kidney injury (AKI) in asphyxiated neonates using different diagnostic criteria, but an apparent observation is that AKI is associated with a poorer outcome. There are no standard nor effective therapies for AKI due to asphyxia, making early recognition vital to implement therapies aimed at preventing or treating anticipated complications. Our study aims to identify incidence and predictors of AKI in asphyxiated neonates treated with therapeutic hypothermia (TH).

Methods: Neonates admitted to our NICU with a diagnosis of perinatal asphyxia and completed 72 hours of TH between the period of January 2011 and May 2018 were enrolled in our study. Demographic data, resuscitation details, laboratory results and use of medications were collected and compared between neonates with AKI and those without. The diagnosis of AKI was made using the neonatal modified KDIGO criteria which is based on an absolute rise of serum creatinine from a previous trough.

Results: Sixty-six neonates who underwent 72 hours of TH for perinatal asphyxia were included in our study. Based on the neonatal modified KDIGO criteria, 33% (22) were found to have AKI. Demographic data including birth weight, gender, Apgar scores at 1 minute and 5 minutes did not differ significantly among the two groups. The AKI-group had a lower gestational age (p=0.006), lower hemoglobin and hematocrit levels (p=0.012 and 0.038 respectively), lower lactate level before and after TH (p=0.013 and 0.03 respectively) and lower troponin-I level after TH (p<0.001). After logistic regression analysis, elevated troponin-I after TH was independently associated with risk of AKI (OR:1.697, 95%CI:1.067-2.699, p=0.025).

Conclusion: The incidence of AKI among asphyxiated neonates who received therapeutic hypothermia is 33%. A persistently elevated troponin-I level after therapeutic hypothermia is independently associated with an increased risk of AK in asphyxiated neonates.