Table 2

Clinical practice points: Hypoxic challenge test (HCT) outcomes

PaO2 ≥ 6.6 kPa (≥ 50 mm Hg); SpO2 ≥ 85%In-flight oxygen not required
PaO2 < 6.6 kPa (<50 mm Hg); SpO2 <85%Repeat HCT with oxygen (flow rate and modality ideally the same as that to be given on board aircraft):

  • Titrate oxygen to maintain PaO2 ≥ 6.6 kPa or SpO2 ≥ 85%

  • Monitor pH and pCO2 if there is a history of hypercapnia

Consider advising against air travel if pH falls to <7.35 and PCO2 increases by > 1 kPa (7.5 mm Hg) from baseline when PaO2 is maintained at ≥ 6.6 kPa or SpO2 ≥85%

  • The use of arterial or capillary blood gas sampling is preferred if available. Blood gases are not routinely measured in children.

  • Recommendations on pCO2 and pH changes are based on the 2015 BTS guideline for home oxygen use in adults.19