Perinatal factors influencing the arterial oxygen tension in preterm infants with RDS while breathing 100 per cent oxygen

Abstract

The relationship of surfactant deficiency, immaturity, and intrapartum complications to the arterial oxygen tension (Pa O 2 ) while breathing 100 per cent oxygen (hyperoxia test) was studied in 88 preterm infants, who were the products of 80 highrisk pregnancies. The hyperoxia test was performed from one to six hours of life. The Pa O 2 was significantly related to the foam stability test (FST) if there was no RDS and the 5 minute Apgar score was ≥6. A low Pa O 2 was significantly related to a history of intrapartum complications and a 5 minute Apgar score ≤5, but not to the FST. A hyperoxia test value greater than 200 mm. Hg was not associated with any deaths from RDS nor with the need of mechanically assisted ventilation. All of the 21 deaths were associated with history of intrapartum complications. A Pa O 2 ≤200 mm. Hg defines the high-risk group for RDS. The highest predictability of deaths from RDS (85 per cent) was further defined by the combination of factors: Pa O 2 ≤200 mm. Hg, intrapartum complications, 5 minute Apgar score ≤5, and arterial pH≤7.20.