“This evidence will help prevent thousands of deaths worldwide each year,” said the University of Sydney’s Professor William Tarnow-Mordi, co-principal investigator of the study.

“Now more trials are urgently needed to improve the quality of survival of premature babies. With innovative investment in clinical trial networks and point-of-care data capture, trials like these could be completed much faster, at a fraction of the cost.”

During the trials, there was a correction to the algorithm that provided data from the oxygen meters. In an extra analysis of data from only the revised oximeters in both trials, the rates of death were 24.5 per cent in the lower-target group (144/587) and 16.9 per cent in the higher-target group (99/586). This was a statistically significant difference (relative risk 1.45, 95% CI 1.15-1.82; P=0.001).

In post-hoc combined analyses using all oximeters, deaths were significantly higher in the lower-oxygen target group than in the higher-target group: 222/1045 (21.2 per cent) versus 185/1045 (17.8 per cent), relative risk 1.20, 95% CI 1.01-1.43; P=0.04.

"The success of trials like these depends on hundreds of parents and health professionals,” said Tarnow-Mordi, professor of neonatal medicine at the university's NHMRC Clinical Trials Centre. "Thanks to their support, the outlook for very preterm babies has never been better – and continues to improve.”