Type of publication:
Conference abstract

Author(s):
Cliff I.J.; Mustfa N.; Stone H.; Hurst C.; *Crawford E.

Citation:
Thorax; Feb 2021; vol. 76

Abstract:
Introduction: Pre-COVID-19, the total number of passengers traveling by commercial airlines rose to 4.3 billion, with Europe amounting to a 7.2% increase. The risks of respiratory compromised patients developing hypoxaemia during flight is well documented. Assessment of these patients is time consuming and often requires specialised equipment. Furthermore, the majority of evidence is based on research into patients with Chronic Obstructive Pulmonary Disease (COPD). The aim of this study is to investigate potential predictive biomarkers relating to the development of hypoxaemia during flight in patients with Motor Neurone Disease (MND). Method(s): 118 MND patients referred into a fitness to fly service (n=118) completed baseline lung function and a Hypoxic Challenge Test (HCT) as part of a risk stratification for (Table presented) planned air travel (77 male). Data from patients requiring inflight oxygen was compared to patients who did not, in accordance with the British Thoracic Society recommendations 2011: Managing passengers with stable respiratory disease planning air travel. Statistical analysis was performed using one-way ANOVA, Kruskal-Wallis, and Chi-Squared tests, as appropriate. Result(s): There was no significant difference between the pass (n=94) and fail (n=24) groups for age, gender, smoking history or BMI. There was a significant difference for all spirometry data (FEV1, FVC and FEV1/FVC ratio – absolute, percent predicted and standardised residuals). Moreover, the resting blood gases (FiO221%) data showed significant difference for all parameters with the exception of pH (<0.001). The Regression analysis showed limited predictive value of spirometry and/or resting blood gas data with the exception of PaCO2 and base excess (BE). Conclusion(s): The predictive value of spirometic paraments and resting blood gases are limited in assessing hypoxaemia during commercial flight in MND patients, with the exception of parameters relating to respiratory failure. Despite the significant difference between the two groups, routine physiological data was limited in the predictive regression equations. We recommend that the safest approach in managing this group of patients is to perform an HCT in all patients intending to use air travel until more evidence-based data is available.

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Type of publication:
Conference abstract

Author(s):
Cliff I.J.; Mustfa N.; Stone H.; Hurst C.; Allen M.B.; *Crawford E.

Citation:
Thorax; Feb 2021; vol. 76

Abstract:
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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