Appropriate levels of oxygen saturation for preterm infants.

Although oxygen is probably the most common therapy delivered to small or sick newborns in the past 75 years, what constitutes appropriate oxygenation for these infants remains highly controversial. The lack of direct evidence, in the form of randomised trials, of the effects of different oxygen levels on meaningful, long-term outcomes has fuelled this controversy and contributed to the significant variation in practice currently seen. Conclusions drawn from the existing evidence regarding oxygen saturation levels for preterm infants include that retinopathy of prematurity rates may be reduced if lower saturation ranges are targeted in the early weeks of life. There is, however, no recent, good quality, trial information that has directly addressed this question. Retinopathy outcomes may also be improved if oxygen saturation is targeted higher in a subset of preterm infants with more severe eye disease in the post-acute phase. There is now direct evidence, from randomised trials, that routine higher oxygen saturation targeting in the chronic phase confers no short- or long-term growth or development benefits. Evidence is now mounting regarding the adverse pulmonary sequelae associated with routine higher, and thus longer, oxygen exposure. Information regarding oxygen saturation levels and early mortality is inconclusive. The major unanswered question that requires urgent resolution is the important long-term effects of targeting lower versus higher oxygen saturation ranges during the first days/weeks of a preterm infant's life. Such an important clinical question can only be answered rigorously and definitively using the randomised trial methodology.