Neonatal serial creatinine levels as an adjunct biomarker in timing of fetal neurologic injury.

Objective: To investigate the rise and clearance of newborn creatinine in perinatal asphyxia as an adjunct biomarker to support or refute allegations of acute intrapartum asphyxia. Study design: In this retrospective chart review, newborns > 35 weeks gestational age were evaluated from closed medicolegal cases of confirmed perinatal asphyxia and reviewed for causation. Data collected included newborn demographic data, patterns of hypoxic ischemic encephalopathy, brain magnetic resonance imaging, Apgar scores, cord and initial newborn blood gases, and serial newborn creatinine levels during the first 96 h of life. Newborn serum creatinine values were collected at 0-12, 13-24, 25-48, and 49-96 h. Newborn brain magnetic resonance imaging was used to define 3 patterns of asphyxial injury: acute profound, partial prolonged, or Both. Results: Two hundred and eleven cases of neonatal encephalopathy from multiple institutions were reviewed from 1987 to 2019 with only 76 cases having serial creatinine values during the first 96 h of life. A total of 187 creatinine values were collected. Partial prolonged and Both had significantly greater degree of metabolic acidosis in the first newborn arterial blood gas in comparison to acute profound. Acute profound and Both had significantly lower 5- and 10- minute Apgar scores in comparison to partial prolonged. Newborn creatinine values were stratified by asphyxial injury. Acute profound injury showed minimally elevated creatinine trends with rapid normalization. Partial prolonged and Both demonstrated higher creatinine trends with delayed normalization. Mean creatinine values were significantly different between the three types of asphyxial injuries within 13-24 h of life at the time when creatinine values peaked (p = 0.01). Conclusion: Serial newborn serum creatinine levels taken within the first 96 h of life can provide objective data of timing and duration of perinatal asphyxia.