Abstract
Targeting lower or higher oxygen levels in preterm infants
Review question
: Is it better to target a lower or higher level of oxygen for babies born very early?
Background
: Giving additional ('supplemental') oxygen to babies born very early ('extremely preterm infants') who have breathing difficulties has been common practice since the 1940s. Despite this, there is little agreement as to what levels of oxygen will maximise short‐ or long‐term survival and development. Technology ('pulse oximetry') that can easily measure the level of oxygen in a baby's blood (oxygen saturation) has been in widespread use since the 1990s. Despite this, until recently there were no randomised trials that had tested whether it is better to target lower or higher oxygen saturation levels in extremely preterm infants, from birth or soon thereafter. As a result there is a great deal of variation in the target ranges aimed for in different newborn care units around the world.
Study characteristics
: The studies we included were randomised trials that enrolled babies born at less than 28 weeks' gestation, at birth or soon thereafter, and targeted oxygen saturation (SpO₂) ranges of either 85% to 89% or 91% to 95%, for at least the first two weeks of life.
Key results
: We included five trials, which together enrolled 4965 infants, in this review. There were benefits and harms associated with both the target ranges tested. Neither the lower nor the higher target range had a significant effect on the rate of death or major disability (the main outcome), on major disability alone or on blindness. However, infants in whom the lower oxygen range was targeted had, on average, a 2.8% increased risk of death, compared to the infants in whom the higher oxygen range was targeted. They also had a 2.2% increase in the rate of a serious bowel condition known as necrotising enterocolitis. Conversely, the infants in whom the lower oxygen range was targeted had a 4.2% decrease in the rate of a serious eye problem, retinopathy of prematurity, requiring surgery or other treatments. The trade‐offs between these benefits and harms may need to be assessed within local settings when deciding on oxygen saturation targeting policies.
Quality of evidence
: We rated the quality of the evidence as high for the key outcomes of death, major disability, the composite of death or major disability, and necrotising enterocolitis. We rated the quality of evidence as moderate for the two eye‐related outcomes (blindness, retinopathy of prematurity requiring treatment), giving us confidence that the overall results are reliable.