Predict respiratory distress syndrome by umbilical cord blood gas analysis in newborns with reassuring Apgar score.

Background: Neonatal acidaemia at birth can increase neonatal morbidity and mortality and it is predictive of neonatal asphyxia. The umbilical blood gas analysis is a valid tool for the evaluation of neonatal acidaemia. However, umbilical cord blood gas analysis is commonly performed in high-risk situations or in the setting of Apgar scores < 7 at 5 min.

Methods: A retrospective cohort study was conducted from June to December 2018 at the Department of mother's and child's health, Poliambulanza Foundation Hospital Institute. Inclusion criteria were: full term newborns with body weight appropriate for gestational age, born by vaginal delivery or caesarean section, reassuring Apgar Score > 7 at 5 min, arterial cord blood gas analysis showing pH < 7.4 or BE <-8 mmol/l or lactate > 6 mmol/l. The aim was to evaluate the predictive role of blood gas analysis for respiratory distress syndrome in newborns with reassuring Apgar Score.

Results: 352 full term newborns were enrolled. Umbilical cord blood artery pH showed an association with respiratory distress syndrome (χ(1) = 10,084, OR (95% CI): 3,9 × 10(2,9 × 10 - 0,048); p < 0,05). ROC curve revealed that the cut-off point of pH was 7.12, with a sensibility and specificity of 68 and 63%, respectively.

Conclusions: Umbilical cord blood artery pH < 7.12 at birth is associated to respiratory distress syndrome in newborns. Blood gas analysis is an important instrument to help health care providers during assistance in the delivery room, but also to early identify newborns at high risk for respiratory distress syndrome and better manage the care of these newborns after birth.