"Rohan Rhodes was an extremely premature baby who was at risk of developing NEC" said coroner Maria E.Voisin.
"He developed this condition which caused his death on the 30th of September."
"On 29th September there were three occasions where he should have had a blood gas test. It's not known what the results would have been but there were lost opportunities which may have resulted in him receiving earlier medical care."
The coroner recorded a narrative verdict.
Flax Bourton Coroners Court heard the medical team planned to keep Rohan on the ventilator ahead of upcoming heart surgery.
But advanced neonatal nurse Amanda Dallorzo took the "autonomous" decision to remove the machine and put a breathing mask on Rohan instead.
His condition deteriorated and he developed NEC, a gastrointestinal disease, which required surgery.
His condition failed to stabilise and he died, aged 36 days.
A neonatal nurse gives evidence on day two of the inquest.
The parents of baby Rohan Rhodes have told the inquest into his death that his ventilator was removed too soon by hospital staff in Bristol.