Abstract
Predicting whether patients with interstitial lung disease (ILD) require supplemental oxygen during air travel is difficult.
Hypoxic challenge testing (HCT) is recommended to determine the need for in-flight oxygen but is only available in specialised centres. We previously identified a formula combining resting PaO2 and the composite physiological index (CPI) [(1.1 x PaO2 on air) - (0.07 x CPI), Lota et al, ERJ, 2012 40: P690] with a score of >9 predictive of fitness-to-fly.
Our objective was to validate this formula in 134 patients who underwent HCT between 2016-2017. HCT was performed by inhalation of a gas mixture containing an FiO2 of 0.15 for 20 minutes. Patients were defined as fit-to-fly if SpO2>85% and/or PaO2>6.6kPa (BTS, 2011).
In the study cohort, mean (±SD) age was 63±12.6 years, 52% female, 33% had a history of smoking and 30% had a diagnosis of idiopathic pulmonary fibrosis. The mean TLCO, KCO, FEV1 and FVC was 33.9±12.8%, 65.8±16.9%, 66.9±19.6% and 68.3±18.9%, respectively. Mean CPI was 55.5±12.5. 51/134 patients (38%) were deemed fit-to-fly according to BTS guidelines. A predictive score >9 was observed in 16/134 patients (12%). Of these, all were fit-to-fly on HCT when SpO2>85% was used as the indicator, with only 2/16 having a borderline PaO2 just below 6.6kPa. The negative predictive value of the score was 87%.
This patient cohort was characterised by severe ILD. Although our formula identified a relatively small proportion of patients, it was highly specific in predicting fitness to fly, and may be usefully applied to patients with less severe ILD, if confirmed prospectively, to identify which patients to refer on to formal hypoxic challenge testing.
Footnotes
Cite this article as: European Respiratory Journal 2018 52: Suppl. 62, PA2912.
This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
- Copyright ©the authors 2018