Hypoxic Challenge Test for airflight in children with respiratory disease.

During airflight, cabins are pressurised to 8000ft (2438m) leading to an effective FiO2 of 0.15. This leads to a fall in oxygen saturation in all passengers, and especially those with underlying lung disease. The hypoxic challenge test using a body plethysmograph can predict a need for supplemental oxygen during airflight, and the process is described.