BTS recommendations for managing passengers with stable respiratory disease planning air travel were published in Thorax in 2011.1 This followed original guidance published in 20022 and an online update in 2004.3 The 2011 recommendations provided an expert consensus view based on literature reviews, aimed at providing practical advice for lung specialists in secondary care. Recognising that knowledge in this area has grown since 2011, and that updated, pragmatic advice regarding which respiratory patients need specialist assessment is required, the Society has commissioned a new clinical statement.
Although air travel appears generally safe for those with respiratory disease assessed previously by a lung specialist,4 a decision to undertake air travel should not be taken lightly. Diverted flights incur significant expense and inconvenience, and a patient whose condition deteriorates during flight can pose huge challenges to airline crew and other passengers. High altitude destinations may also be problematic.
European and North American regulatory authorities limit maximum cabin altitude to 2438 m (8000 ft) under normal operating conditions.5–7 The choice of 2438 m was based on the oxyhaemoglobin dissociation curve, which shows that up to this level arterial oxygen saturations (SaO2) remain >90% in the average healthy individual.8 Some newer commercial aircraft have a lower normal cabin altitude, for example, the Boeing 787 Dreamliner. However, passengers booking such flights should note that airlines may, for operational reasons, switch at short notice to an aircraft with a higher normal cabin altitude.
Besides the passenger’s respiratory condition and significant comorbidities, a decision regarding suitability for air travel should consider flight duration and timings, destination (especially if at altitude or subject to extreme weather conditions), equipment and medications, and whether equipment will operate effectively and safely at altitude.
There have been developments in three key areas over the last decade. The first is an attempt, with research from several groups, to define more precisely the value and role of the hypoxic challenge test (HCT). This has included examining the accuracy of other, more routinely available lung function parameters, in predicting hypoxaemia during air travel. HCT can be expensive in terms of equipment and consumables; and demands additional staff time. A ‘negative’ HCT (where in-flight oxygen is not considered necessary) takes around 30 min; if oxygen titration is needed it takes around 60 min. In contrast, spirometry requires 20 min, a walk test 30 min, and ‘full’ lung function testing 45 min.9 Results of such assessments may already be available as part of routine clinical care.
The second development has been increasing recognition that, although early research in this area focused on patients with chronic obstructive pulmonary disease (COPD), other patient groups may respond differently to altitude-related hypoxaemia. Although data remain limited, available evidence no longer appears to support a ‘one size fits all’ approach.
Finally, the equipment used to deliver oxygen has changed significantly over the last decade, with much greater availability of portable oxygen concentrators (POCs). For overseas travel, patients usually need to lease a POC privately, since UK companies do not generally allow their equipment to be taken out of the country. If a POC is to be used in-flight, the equipment must be approved by the airline before travel. There are now a wide variety of such devices, providing varying flow rates and modes of delivery (continuous flow vs pulse-dose), and not all are suitable for all individual patients.
Attention has, therefore, been drawn in this Statement to newer data, especially those published since the 2011 BTS recommendations.1 Readers wanting more detailed background information on physiology and the flight environment should consult the 2002 and 2011 BTS documents.1 2
The clinical statement provides practical advice for healthcare professionals in primary and secondary care managing passengers with pre-existing respiratory conditions planning commercial air travel, including those recovering from an acute event/exacerbation. It provides information for patients and carers; and is also intended to be helpful to patient support groups, airlines and associated medical services. Passengers returning home with a new diagnosis should be reviewed in the light of the presenting condition and individual circumstances. The document does not cover emergency aero-medical evacuation, or travel on non-commercial flights. Pregnant passengers with respiratory disease should also consult Royal College of Obstetricians and Gynaecologists guidance (see online supplemental appendix 1).[thoraxjnl-2021-218110supp001.pdf]
The Statement addresses adults and children with the following conditions or undergoing the following procedures:
Preflight assessment is described. Appendix A provides information on logistics for air travel with equipment (nebulisers, oxygen and ventilators); Appendix B provides technical information for respiratory physiologists. Sources of useful information, Information for primary care healthcare practitioners and for patients are provided in online supplemental appendices 1–3.[thoraxjnl-2021-218110supp002.pdf][thoraxjnl-2021-218110supp003.pdf]
Heart disease and HIV are excluded, as are emergency repatriation and travel on military or other non-commercial flights including helicopter travel. The Terrence Higgins Trust and British Heart Foundation provide advice on travel with HIV and heart conditions respectively (see online supplemental appendix 1).