Bronchiolitis of Infancy Discharge Study

What is BIDS?

The BIDS study was a double blind randomised control study with infants randomly allocated either a standard or a modified oxygen monitor during their hospital stay. The modified monitors would display oxygen saturation of 94% when really it was 90%. Doctors, nurses and parents did not know what kind of monitor the infant had been assigned to avoid bias.


Throughout two winter Bronchiolitis seasons 615 infants admitted to hospitals in Scotland and the South West of England were recruited onto the study. This is an excellent achievement as the original recruitment target was 600.

57% of participants were boys and 43% were girls. The average age of participating infants was 21.3 weeks. 43% of participating infants came from households that contained at least one smoker.

Follow up

Recruited infants were followed up for six months after randomisation to measure a range of outcomes including healthcare re-attendance rates and parental anxiety scores.


Analysis of the results commenced in early 2014. The primary outcome measure was number of days to cough resolution. This study showed equivalence, meaning that infants discharged with 90% oxygen saturation took the same time to stop coughing as infants who were not discharged until their oxygen saturation reached 94%. Earlier discharge from hospital did not result in more safety issues. There was no significant difference in the level of healthcare reattendance between the two treatment groups.


BIDS team would like to thank all staff, parents and infants who participated from Aberdeen, Bristol, Dundee, Edinburgh, Exeter, Glasgow, Kilmarnock and Truro.


For further information on the BIDS study please contact the Chief Investigator (CI), Dr Steve Cunningham, or the Trial Manager, Morag MacLean.