Pre-travel testing would help minimize the risk for hypoxemia by ensuring that a higher level of oxygen is delivered to individuals who need it. In patients with COPD already on daily oxygen therapy and patients at risk for hypoxemia (reduced diffusion capacity, low normal oxygen saturation), obtaining a HAST is recommended. Patients are administered 15% oxygen at sea level to simulate the lowered oxygen pressure that they would encounter in flight.1 A new oxygen requirement is determined, generally 1 to 2 liters per minute more than their baseline level. In areas where HAST is not available, desaturation on pulse oximetry during a 6MWT may help identify patients who may need additional oxygen during air travel, although this is felt to be less precise. Seated leg exercises and ambulating at regular intervals during the flight can help decrease the risk for venous thromboembolism.
Dr Sims: The exertion of ambulating from the security checkpoint to the departure gate or between gates on layovers can obviously cause dyspnea. This can be handled by arriving early and leaving extra time for rest breaks or using wheelchairs and shuttles in the terminal.
Patients prone to low oxygen levels on land may have worsening low oxygen levels in the air. Planes, when at altitude, are not pressurized to sea level but something like approximately 8000 feet above sea level.1 This means that patients who do not require oxygen on land may require oxygen during flight. They should talk with their COPD provider about plane travel to assess [their] risk and make plans well in advance. Some centers [perform] HAST, and if patients have a low oxygen level they get nasal cannula oxygen added under the mask until their levels are normalized; [the results give the provider] a best guess [regarding] how much they will need during flight. That test is not routinely [performed], so some providers just assume that the usual oxygen dose needed for exertion will be sufficient for sitting still on a plane.
Being on a plane with so many other people in a relatively small space means a higher than average risk of picking up an infection, often a viral [infection].1 For this, the best preventive measure is hand washing, especially before eating. Some patients bring a small bottle of alcohol-based handwash to use.
If you show up at the gate with oxygen and no letter from your doctor, you may not be allowed to board the plane, so it is very important to plan ahead and get the letter and any necessary equipment. Oxygen concentrators are allowed on planes and must be scanned like carry-on items, but oxygen tanks are not allowed under any circumstances. Some airlines will provide oxygen for patients, but the cost is usually very high — I have seen up to $150 per leg of the trip. Most people use their own portable concentrator if they have one or they rent one from their durable medical equipment (DME) provider who supplies their home oxygen. This also takes advanced planning, so I advise patients to plan at least a month before they fly. They should be working on getting a doctor’s note and speaking with their DME supplier if they need equipment.
Running out of oxygen during the flight can lead to low oxygen levels and [resulting] symptoms. Some airlines require that patients have a surplus of oxygen in case the plane is delayed and needs to circle the destination airport before being allowed to land. For a portable concentrator, this means having extra battery life — either a longer capacity battery or a spare battery. I advise having approximately 25% to 30% extra — for example, at least 4 hours of battery life for a 3-hour flight.
Pulmonology Advisor: How should clinicians advise patients on these matters and assess their fitness for flying?
Dr Khabbaza: In patients with COPD who have chronic hypoxic respiratory failure and patients at risk for hypoxemia, I recommend they undergo a HAST before traveling. Most patients with controlled mild to moderate COPD and mild deviations in diffusion capacity with normal oxygen saturations do not need to be tested. Additionally, advising patients to travel with their pulse oximeter and check saturations periodically during flight would be helpful, as most patients know how to adjust their oxygen delivery should saturation if it is less than 88%. Patients should keep their short-acting rescue medications easily accessible in case they develop acute symptoms. Avoiding sedating medications and alcohol should be advised, given their lower respiratory reserve, especially during longer flights [because] desaturation can occur during sleep.
Dr Sims: Make sure patients know they need to plan way ahead for plane travel — both to get advice on [maintaining] oxygen levels from their provider and to handle necessary logistics with the airline and DME supplier.
Counsel them that for each flight they need a note from their doctor that usually needs to specify that oxygen is required and for which portions of the flight (for example, just at altitude or also during taxi, takeoff, and landing), the oxygen dose required, and an assertion that the patient is capable of operating the oxygen concentrator on their own. Some airlines even request that the specific brand of concentrator be specified, but that is less common in my experience.
Pulmonology Advisor: What should be the focus of future research on this topic?
Dr Khabbaza: Accurate and reliable testing for patients in areas where HAST is not readily available may be beneficial. Several studies with proposed algorithms using oximetry with ambulation have been promising. Overall, air travel in patients with COPD is safe and generally requires just a slight increase in oxygen delivery in patients with or without pre-travel HAST. With all the newer modes of oxygen delivery now available, studies comparing and [evaluating] their reliability during air travel may be beneficial, although I am not sure an in-flight pulmonary function laboratory for testing will fit into most research budgets.
1. Ergan B, Akgun M, Pacilli AMG, Nava S. Should I stay or should I go? COPD and air travel. Eur Respir Rev. 2018;27(148):180030.
2. Peterson DC, Martin-Gill C, Guyette FX, et al. Outcomes of medical emergencies on commercial airline flights. N Engl J Med. 2013;368(22):2075-2083.
3. Edvardsen A, Akerø A, Hardie JA, et al. High prevalence of respiratory symptoms during air travel in patients with COPD. Respir Med.2011;105(1):50-56.
4. Coker RK, Shiner RJ, Partridge MR. Is air travel safe for those with lung disease? Eur Respir J. 2007;30(6):1057-1063.