Trial Summary


To determine whether less oxygen is safer and more effective in the care of very premature infants.

Study Design

Multi-centre, Double blind, Randomised Controlled Trial



  • They are less than 276 weeks gestation
  • They are less than 24 hours old
  • Parental consent is obtained


  • There is a congenital anomaly affecting oxygenation or long term development
  • Death is imminent
  • Two years follow-up is judged unlikely


To establish whether the survival and long term developmental progress of babies of <28 weeks gestation, given oxygen to maintain a fractional oxygen saturation range of 85-89%, is comparable to that achieved by giving babies fractional saturation kept in the 90-95% range, until the baby is breathing air

Primary Outcome

Survival & Major disability at 2 years postmenstrual age

Major disability is any of:

- severe visual loss (cannot fixate or is legally blind),

- cerebral palsy with inability to walk at 2 years postmenstrual age,

- deafness requiring hearing aids

Secondary Outcomes

    • ROP of prematurity, duration of oxygen therapy, PDA, NEC, chronic lung disease, growth, re -admissions to hospital up to 2 years postmenstrual age, cerebral palsy and unable to walk at 2 years, blindness (<6/60 vision), or deaf with aid, mean MDI and PDI scores


Treatment: Oxygen saturation - measured with adjusted, masked Masimo Radical

    • Oximeters targeting saturation ranges of (lower) 85-89% and (upper) 91-95% will be masked to display a range of 88-92%.The offset will be 3% above or below the actual range


2 year parental and paediatrician questionnaires, plus psychological assessment including Mental Development Index (MDI) and the Psychomotor Development Index (PDI) on the Bayley II Scales assessments

Sample size & Power

A sample of 1200 infants has 80% power (2p = 0.05) to detect relative risk reductions of 22% in severe ROP and of 50% in CLD, and to exclude an absolute 8% increase or decrease in the composite outcome of death or major disability at 2 years (from 37% to 45% or from 37% to 29%). This would mean one less infant who died or was disabled for every 12 given less oxygen