• Neonatology
• Respiratory Medicine

The practice of titrating supplemental oxygen to target levels of pulse oximeter saturation (SpO₂) evolved with little supporting evidence. Before this, the recommended practice was to target transcutaneous or arterial PO₂ to 6.7–10.7 kPa (50–80 mm Hg).1 2 Recent evidence shows that SpO₂ targets below 90% increase mortality and necrotising enterocolitis and higher targets increase retinopathy of prematurity treatment, but not blindness or disability.3 4 The optimal SpO₂ target range for preterm infants is unknown. Trials of higher SpO₂ targets are needed to determine any further survival advantage to be gained. Because the haemoglobin oxygen dissociation curve flattens at higher SpO₂, the likelihood of hyperoxia at higher SpO₂ needs to be better understood before such trials are designed. We explored the relationship between arterial oxygen tension …