Ms Leigh Seccombe, Senior Scientist, Department of Thoracic Medicine
& A/Prof Matthew Peters, Staff Specialist
CONCORD REPATRIATION GENERAL HOSPITAL
The airline industry continues to boom despite the recent downturn of the world economy. More than four billion people travel by air each year and frequently, the question is asked, “Am I fit to fly?” Many patients living with lung disease have an increasing yearn to travel and this article will help you to understand the possible risks of air travel.
What is the environment like in a modern aircraft?
Commercial aircraft can fly at a height of up to 41,000 feet above sea level. It is not possible to survive at this altitude, so outside air is pumped into the cabin to pressurise it. As cabin pressure is lower than the air pressure at sea level, all airlines follow regulations to ensure that the pressure is maintained at a level higher than 75% of sea level pressure. In general, on longer trips and in larger aircraft, the cabin pressure is kept at a higher level than the minimum allowed. On short flights, like Sydney to Melbourne, the aircraft takes a long time to ascend and then soon descends, so the period of low pressure is actually very short and the risks are small for most people.
What is the effect of these lower oxygen levels?
Without being aware of it, healthy passengers increase their breathing rate to combat the lower oxygen onboard aircraft. They will still experience a fall in oxygen saturation of about 5%, but this is usually without symptoms. This fall is often greater in patients with lung problems but, despite this, only a few report difficulties in breathing during their flight. However, patients who have lower oxygen levels, before they even start the flight, will experience sharp falls in oxygen saturation in the aircraft and will usually need oxygen in-flight. Any light exercise, such as walking around the cabin, will decrease oxygen levels further, by another 5-10% and the heart rate will rise.
What oxygen levels are considered risky?
Current international guidelines state that if your sea level oxygen saturation is greater than 95%, you are fit to fly without any testing being necessary. Another rough test is that if you can walk 50 metres without stopping, you are probably going to pass more complex tests. The lung function laboratories of most major hospitals can perform a test during which the low oxygen levels in the cabin environment can be simulated. This will allow your specialist to see how low your oxygen levels fall and you will experience the sensations – admittedly for only 20 minutes or so. If oxygen levels fall below 85%, then we recommend a discussion with your specialist about the risks of flying and whether these risks should be minimised with supplemental oxygen in-flight. As most of the emergencies in flight are related to heart problems, we tend to err on the side of recommending oxygen in patients who have both heart and lung problems.
What if I am unwell when I plan to travel? I am desperate to travel. Should I just take the risk?
Please don’t fly when you are not at your best. Many of the reported critical incidents are related to patients who went on a journey when they were unwell. As a rough guide, you should have returned to your usual health for seven days before you fly. From time to time, health professionals encounter a patient who is prepared to accept ‘any risk’ to travel long distances. Some are at a stage in their illness where the risks seem immaterial and airlines are right to be concerned about carrying these patients. Although rare, deaths in-flight can occur. A serious medical deterioration may require that a flight be diverted at great cost and inconvenience to the airline, crew and other passengers.
Some practical travel advice
- Consider the destination, not just the flight! What is the altitude? Will heat or humidity be oppressive and cause distress that will affect your enjoyment of your travel experience? Are you travelling to a country with an influenza epidemic?
- Purchase a changeable ticket, just in case you need to delay your plans due to ill health.
- Take all your medical documentation with you.
- If you are travelling overseas, ensure that you have travel insurance or access to health care. Insurance can be difficult for those with chronic illnesses but some countries have a reciprocal health care arrangement with Australia that will cover you for emergencies (but not the high costs of medical evacuation if needed). If you limit your travel to Australia, you do have the advantage that the doctor caring for your lungs in an Australian hospital has the ability to contact your doctor more easily.
- Check in early for your flight.
- If you need oxygen, arrange it well in advance. If necessary, ask for a wheelchair for use within the terminal
- Request a seat near a bathroom on the plane and if you are on a short flight, use the bathroom in the terminal before you board.
What if I need oxygen in-flight?
If you require oxygen in-flight, call your airline well in advance of your trip, or check its website, which should outline the steps that need to be taken to obtain oxygen. The most common source of oxygen supply on aircraft is via a compressed gas cylinder which is stored under your seat. This needs to be pre-ordered and may be supplied by the airline itself (charges may apply), or ordered from the airline’s preferred oxygen supplier e.g. Air Liquide or BOC. Check with the airline for guidance. Most commercial airlines allow portable oxygen concentrators which can be carried with you at all times and stored under the seat in front of you. Check with the airline that your machine is on their list of acceptable medical equipment. Happily, most patients living with lung disease will be able to travel and to do so safely.
This article was published in the May 2010 edition of The Australian Lung Foundation’s newsletter, LungNet News, and has been reproduced with permission from The Australian Lung Foundation.
The Australian Lung Foundation:
Free-call: 1800 654 301