BackgroundFollowing recent recommendations, the oxygen saturation (SpO₂) target range for preterm infants in our nursery was narrowed towards the higher end from 85%–95% to 90%–95%. We determined the effect of narrowing the SpO₂ target range on the compliance in target range and distribution of SpO₂ in preterm infants.MethodsBefore and after changing the target range from 85%–95% to 90%–95%, infants <30 weeks of gestation receiving oxygen were compared during their admission on the neonatal intensive care unit. For each infant, distribution of SpO₂ was noted by collecting SpO₂ samples each minute, and the percentage of time spent with SpO₂ within 90%–95% was calculated. Oxygen was manually adjusted. Hypoxaemic events (SpO₂ <80%) where oxygen was titrated were analysed.ResultsData were analysed for 104 infants (57 before and 47 after the range was narrowed). The narrower range was associated with an increase in the median (IQR) SpO₂ (93% (91%–96%) vs 94% (92%–97%), p=0.01), but no increase in median time SpO₂ within 90%–95% (49.2% (39.6%–59.7%) vs (46.9% (27.1%–57.9%), p=0.72). The distribution of SpO₂ shifted to the right with a significant decrease in SpO₂ <90%, but not <80%. The count of minute values for Sp0₂ <80% decreased, while the frequency and duration of hypoxaemic events and oxygen titration were not different.ConclusionNarrowing the target range from 85%–95% to 90%–95% in preterm infants was associated with an increase in median SpO₂ and a rightward shift in the distribution, but no change in time spent between 90% and 95%.