Purpose Currently there is no UK consensus on fitness to fly in congenital heart patients. Evidence for the need for supplemental oxygen during flights for cardiac patients is limited. We review our use of a hypoxia challenge testing (HCT) to simulate aeroplane conditions and advise patients on fitness to fly and the requirement for supplemental oxygen.

Methods We reviewed all paediatric patients with cardiac conditions referred for a hypoxic challenge test since introduction of the test in 2016. Using a purpose built box this mimics the environmental drop in oxygen availability observed during a flight at high altitude. Patient saturations continuously monitored over a 20 min period.

Results We reviewed 11 patients over a 1 year period. The mean age was 78.2 months (range 8–285 months). The mean weight was of 26.5 kg (range 8.1–86.4 kg). Average baseline saturation was 86% (range 79% – 99%).

Of the 11, 10 had some form of cardiac intervention, 9 of which were complex cardiac surgery and of those 6 had a single ventricle repair.

4 (36%) of patients were prescribed supplemental oxygen on the basis of testing.

Conclusion In order to establish which patients require supplemental oxygen we recommend HCT to provide objective data. This information is of great help to families and clinicians in planning holidays and often avoiding the need for supplemental oxygen that can be cumbersome and expensive to arrange.