Arterial oxygen tension (Pao2) values in infants <29 weeks of gestation at currently targeted saturations

BACKGROUND: Oxygen saturation (Spo(2)) monitors are commonly used to determine the need for supplemental oxygen. We aimed to describe the range of arterial oxygen tensions (Pao(2)) observed in preterm infants at saturation levels targeted in current trials. METHODS: In a cohort of 98 consecutive infants born at <29 weeks' gestation, the Pao(2) from each arterial blood gas result during the first week of life (n = 2076) was matched to the Spo(2) at time of sampling. The mean (95% CI) Pao(2) was calculated for each saturation. RESULTS: The 95% CI of Pao(2) for the Spo(2) range 85-95% was 3.8 to 8.9 kPa. The mean (95% CI) Pao(2) at a saturation of 85% was 5.3 (3.8 to 6.8) kPa and at a saturation of 95% it was 7.2 (5.5 to 8.9) kPa. CONCLUSION: Saturations within the range 85-95% largely exclude hyperoxia in preterm infants <29 weeks' gestation but permit Pao(2) values far lower than those recommended in traditional guidelines.