Dr Coker, why was new guidance on this topic needed?
The latest BTS recommendations for managing passengers with stable respiratory disease were published over 10 years ago, in 2011. Over the last decade there have been several developments in this area, for which we felt a new statement was required.
To ensure that the clinical statement reflected a wide range of perspectives and expertise, the group’s members included healthcare professionals from secondary and primary care, paediatrics, nursing, respiratory physiology, and physiotherapy.
Who is this statement for?
The newly published BTS Clinical Statement on air travel for passengers with respiratory disease provides practical advice for healthcare professionals in primary and secondary care managing passengers with pre-existing respiratory conditions, including those recovering from an acute event (or exacerbation), who are planning commercial air travel.
Why is it important to have this guidance in place?
Despite concerns about its environmental impact, security considerations and a global pandemic, air travel seems likely to remain popular for the foreseeable future. International Civil Aviation Organization figures show that 4.5 billion passengers flew worldwide on commercial scheduled flights in 2019 (1). In 2019, the UK Civil Aviation Authority recorded that over 300 million passengers were handled by UK airports (2).
It’s important that wherever possible people with lung disease can access air travel safely when they wish to, and that their condition does not impose unnecessary limits on their enjoyment of life. People fly for a plethora of reasons beyond leisure travel: while many will visit family and friends, many others do so for work, education and more. Respiratory disease can itself be a burden to people’s daily activities. We need to prevent putting further unnecessary barriers in their way, while maintaining an all-important focus on patient and passenger safety.
Travelling at (or to) high altitude can exacerbate pre-existing respiratory conditions and put a patient at increased risk; and administering care on board an aircraft can pose significant challenges. A respiratory emergency in flight obviously causes distress to the patient but can also cause disruption for the airline, cabin crew and fellow passengers.
The UK Flight Outcomes Study (3) showed that air travel is generally safe for passengers with respiratory disease who have been assessed beforehand by a lung specialist, emphasising the importance of careful pre-flight evaluation.
Are there ways to predict how a patient will react to flying?
One of the most common approaches has been using hypoxic challenge test (HCT) to predict hypoxaemia during air travel. This is an expensive test in terms of time and equipment. Even a ‘negative’ HCT, where in-flight oxygen is not deemed necessary, can take up to one hour.
To put this in context, this compares with around 20 minutes for spirometry, 30 minutes for a walk test, and 45 minutes for ‘full’ lung function testing. The results of these more commonly used assessments may already be available as part of routine clinical care, therefore avoiding the need for further investigation.
What does the clinical statement focus on?
Firstly, the place of the hypoxic challenge test (HCT). The Clinical Statement reminds readers that those with clinically stable conditions who have previously undergone HCT do not need a repeat HCT. It also highlights that HCT should be restricted to those patients who really need it. Importantly, this includes those with existing or previous hypercapnia and patients considered to be at risk of hypercapnia, including those taking medication(s) which can cause respiratory depression.
Secondly, there is increasing recognition that different respiratory conditions may respond differently to altitude-related hypoxaemia. The ‘one size fits all’ approach is no longer felt appropriate. In the statement we address the different approaches that should be taken when managing a range of respiratory conditions, whether obstructive or restrictive.
Finally, the equipment used to deliver oxygen has changed significantly since 2011, with much greater availability of portable oxygen concentrators (POCs). We have therefore included information on the logistics of travelling with equipment including POCs, and technical advice for respiratory physiologists, including recommendations about managing patients with hypercapnia.
As British manufacturers do not usually allow patients to take NHS equipment overseas, patients usually need to lease a POC privately. To help patients and carers we have included advice on airline-approved POC devices, including battery requirements. We also highlight the limitations of pulse-dose oxygen delivery.
Is there any further reading you would recommend on this topic?
Those looking for more detailed background information on physiology and the flight environment will find the 2002 (4) and 2011 BTS documents on this topic very exhaustive. Those wanting more general advice regarding air travel during the COVID-19 pandemic can find more information in the 2020 BTS COVID-19 Air Travel Statement (5).
References
- International Civil Aviation Organisation icao.int accessed 21st October 2021
- Civil Aviation Authority website caa.co.uk
- Coker RK, Shiner RJ, Partridge MR. Is air travel safe for those with lung disease? ERJ 2007;30(6):1057-63)
- Managing passengers with respiratory disease planning air travel: British Thoracic Society recommendations, Thorax 2002;57:289–304
- BTS COVID-19 Air Travel Statement 2020: https://www.brit-thoracic.org.uk/about-us/covid-19-resumption-and-continuation-of-respiratory-services/#planning-air-travel/