Umbilical arteriovenous PO2 and PCO2 differences and neonatal morbidity in term infants with severe acidosis

OBJECTIVE: In term infants umbilical cord gas analysis is a poor predictor of immediate newborn complications associated with intrapartum asphyxia, unless the umbilical arterial pH is less than 7.00. We investigated whether umbilical arteriovenous blood gas differences may better predict asphyxia-related complications. STUDY DESIGN: The study population consisted of 82 term, nonanomalous, singleton, live-born infants with severe umbilical acidosis (pH <7.00). Umbilical arteriovenous pH, PCO2, and PO2 differences were correlated with Apgar scores and the presence of seizures, hypoxic-ischemic encephalopathy, cardiopulmonary and renal dysfunction, and abnormal development in the neonatal period. RESULTS: Umbilical arteriovenous pH, PCO2, and PO2 differences were interrelated (p < 0.0001), but these parameters correlated only weakly with I-minute and 5-minute Apgar scores. An arteriovenous PCO2 difference >25 torr was a highly sensitive and specific parameter in identifying asphyxiated infants with seizures, hypoxic-ischemic encephalopathy, cardiopulmonary and renal dysfunction, and abnormal development in the neonatal period. Arteriovenous Pop differences were less sensitive in the detection of neonatal morbidity than arteriovenous PCO2 differences. CONCLUSION: Umbilical cord blood arteriovenous PCO2 differences provide a new tool to predict neonatal morbidity and permanent neurologic injury in term infants with perinatal asphyxia.