Type of publication:
Cliff I.J.; Mustfa N.; Stone H.; Hurst C.; Allen M.B.; *Crawford E.
Thorax; Feb 2021; vol. 76
Introduction: The risk associated with commercial flight for respiratory compromised patients is well known. Many of the assumptions are based on studies that have included patients with Chronic Obstructive Pulmonary Disease (COPD) and have often been extended to other respiratory and non-respiratory disorders. This study aimed to examine differences in physiological parameters and Hypoxic Challenge Test (HCT) outcome in patients with Motor Neurone Disease (MND), Interstitial Lung Disease (ILD) and COPD. Method(s): Respiratory patients who were referred into a fitness to fly service (n=225) with COPD (n=51), MND (n=118) and ILD (n=56) completed baseline lung function and a HCT as part of a risk stratification for planned air travel. Statistical analysis was performed using one-way ANOVA, Kruskal-Wallis, and Chi-Squared tests, as appropriate. Result(s): Demographic data relating to age, smoking history and BMI were significantly different between the patient groups. Spirometric data showed significant differences in Forced Expiratory Volume in one second (FEV1) absolute, percent predicted and standardised residuals, however there was no significant difference in Forced Vital Capacity (FVC) absolute or percent predicted. Resting capillary blood gases (CBGs) (FiO221%) showed significant differences between patient groups in all parameters with the exception of pH. Responses to the hypoxic mix during the HCT (FiO215%) showed differences in all CBG values with the exception of pH. This was also mirrored in the corrective values (FiO228%). The difference between the PaO2 at rest (21%) and during the HCT (15%) is higher in the MND and ILD groups (2.66and 2.74 kPa respectively) versus the COPD group (2.2kPa). The HCT fail rate was greatest for the COPD group (table 1). Conclusion(s): In this retrospective, exploratory examination, the physiological data supports significant differences between the disorders for the majority of data. The assumptions and algorithms based on the study of COPD patients cannot be assumed for MND or ILD, and these groups need to be (Table presented) specifically studied to better understand their response to the commercial cabin environment.
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