RESUMO
A small randomised trial in 1952 showed that excess oxygen use might well be causing a major epidemic of retinal blindness in preterm babies. That single study of just 65 babies was enough to throw doubt on a longstanding treatment strategy of oxygen therapy and highlighted just how powerful a tool the randomised controlled trial could be. Confirmatory evidence from a co-operative trial 4 years later involving 212 babies banished all residual doubt and we should reproach ourselves that we have still not learnt after 50 years how to optimise oxygen delivery to the preterm baby, making further use of this powerful research tool. Two well-conducted trials have recently shown that avoiding subclinical hypoxaemia (a fractional SaO(2) of less than 92%) in babies more than a month old does nothing to improve later growth or development. It is now time the same question was asked of babies less than a month old. This is particularly important in babies of less than 28 weeks' gestation, who currently remain at serious risk of chronic lung disease and permanent retinal damage.