By Dr Eddy Bajrovic*
A crowded cabin is no place to get seriously sick.
But, illness during an international flight is not uncommon, occurring on around one in every 600 departures, according to a review of mid-air medical emergencies published this month in The New England Journal of Medicine**.
The review was carried out to give doctors an understanding of the kind of medical issues they are more likely to encounter if a fellow passenger becomes ill.
Fortunately, the chances of treatment being available are fairly good: a doctor responded to the pilot’s call for medical assistance in almost half (45%) of the 191 in-flight emergencies reviewed in an earlier US survey in 2006.
And, even if a doctor, nurse or other health professionals are not on board, ground–based medical services are contracted to provide medical advice to flight attendants, who themselves receive mandatory training in basic procedures, such as cardio-pulmonary resuscitation.
Most common medical emergencies
The most common mid-air medical events include:
CARDIAC ARREST – By far the most deadly emergency is a cardiac arrest (when the heart stops beating). While relatively rare – accounting for only 0.3% of in-flight medical emergencies – cardiac arrest is responsible 86% of all in-flight deaths.
HEART ATTACKS – Heart attacks and related problems like angina made up 8% of emergencies. Medical kits aboard the plane are likely to have only the most basic of equipment or medication but should have the gold standard treatment of aspirin, and also nitro-glycerine to relieve chest pain. Oxygen can also be administered or the pilot may descend to a lower altitude to help with oxygenation of the blood.
STROKES – Strokes or suspected strokes account for 2% of emergencies on flights. Administering oxygen is one treatment option, but aspirin is not: many strokes are caused by bleeding in the brain and aspirin may worsen the bleeding.
ALTERED MENTAL STATUS – This category covers a broad range of medical problems. One potential cause is complications from diabetes (1.6% of emergencies) along with a seizure or its aftermath (5.8%).
FAINTING – Fainting or feeling faint is a common occurrence (37%). The researchers said a number of factors may contribute to this, including: lower cabin pressure, dehydration cause by the cabin’s dry air, a change in eating patterns, or fatigue from delayed flights.
BREATHING DIFFICULTIES – Breathing difficulties account for 12% and apart from the aircraft’s supplemental oxygen, the only equipment usually available from the plane’s medical kit is a salbutamol inhaler, which relaxes muscles in the airways and increases air flow to the lungs.
PSYCHIATRIC EMERGENCIES – These make up 3.5%. If the distressed passenger can’t be calmed, they may need to be physically restrained to protect themselves and other passengers.
Finally, trauma from air turbulence, trip falls and stumbles are quite common. Generally the injuries sustained are minor, but occasionally result in fractures – usually a leg.
So, who is fit to fly – or not?
Often, there are no clear guidelines on whether an emergency landing is warranted, the authors of the review noted.
The final decision is always up to the pilot – not the doctor – but having a flight disrupted due to a medical emergency is rare. Of the 191 emergencies examined in the 2006 survey, only 3% were deemed to warrant the plane either being diverted mid-flight or returning to the airport where the journey began.
So, is it safe to travel if you or a member or your family has a respiratory or cardiovascular disorder, or has had a stroke? What about during pregnancy?
A number of these conditions preclude flying due to changes in cabin pressure, long periods sitting in a confined space, or other considerations.
The highly regarded Manual of Travel Medicine, which is widely consulted by Australian doctors who work in this field of travel medicine, lists around two dozen conditions that might prevent or delay air travel. But, the authors concede that their list is not exhaustive.
RESPIRATORY (LUNG) CONDITIONS
The Manual notes that patients with the following respiratory disorders should not travel by air:
- An active serious respiratory infection, particularly tuberculosis (TB) – which is not common in Australia.
- Pulmonary hypertension (high blood pressure in the lung).
- Inadequate lung function (where testing shows lung capacity or ventilation of less than 50%, elevated carbon dioxide retention in the blood, or very low concentrations of oxygen in the blood.)
Someone who relies on continuous oxygen therapy on the ground should not travel by air, nor should those patients with active bronchospasm, such as poorly controlled symptomatic asthma, or cyanosis (poor circulation or inadequate oxygenation of the blood) while at rest or when exercising.
Anyone who has had lung surgery should not travel by air within 2 weeks of the operation, while a patient recovering from a pneumothorax (collapsed lung) should not travel until an x-ray shows the lung has fully recovered.
CARDIAC (HEART) CONDITIONS
People with certain heart conditions also should not travel by air. These include:
- Unstable angina (chest pain or discomfort caused by a lack of oxygen reaching the heart muscle). Typically angina is caused by narrowed or blocked coronary arteries.
- Uncontrolled heart failure or hypertension (abnormally high blood pressure).
- Uncontrolled cardiac arrhythmia (irregular heartbeat).
Anyone who has had a heart attack (myocardial infarction) should not travel for 3-4 weeks after recovery.
Don’t fly if…
Anyone who becomes breathless after walking 50 metres at ground level should not travel by air.
A stroke patient should delay flying for 2 weeks.
Similarly, someone who has experienced a venous thromboembolism (a blood clot that breaks loose and travels in the blood) should not travel by air for at least a month afterwards and should receive treatment to have their blood thinned for the flight.
Scuba divers should not fly within 12-18 hours of their last dive for fear of experiencing potentially fatal decompression sickness, more commonly known as ‘the bends’. However, this also depends on the number of times they’ve dived.
People with severe anaemia should not travel without their doctor’s approval. A doctor’s assessment of the risks of flying is also advisable for people with sickle cell disease, or those who recently experienced inflammation of either the middle ear (otitis media) or the sinuses (sinusitis).
The pregnant air traveller
Air travel is generally safe for pregnant women.
The second trimester (13-27 weeks) is considered to be the safest period for flying, but up to 36 weeks is fine for mums-to-be as long as there are no medical or obstetric issues that may cause complications. Beyond 36 weeks flying is not advisable and most airlines don’t allow it.
Most commercial aircraft are pressurised to an altitude of 2440 metres above sea level and this can reduce the amount of oxygen absorbed into body tissue, a condition called hypoxia.
In addition, pregnant women are at increased risk of venous thromboembolism during a long flight. The risk can be reduced by taking frequent walks in the aisle, drinking plenty of water, and wearing compressions stockings that extend above the knee.
Read more about travelling during pregnancy.
If you’re pregnant or hoping to be, or you have a medical condition, the time you’ll spend in the air is just one factor that should be weighed up in assessing the potential health risks of international air travel.
Discuss your plans and your current condition with a doctor – preferably one experienced in travel medicine – well ahead of departure.
It’s better to know that you’re fit to fly before booking your flights or accommodation.
* Dr Bajrovic is the Medical Director of Travelvax Australia.
** In-Flight Medical Emergencies during Commercial Travel. Jose V. Nable at al., M.D., N.R.P., Christina L. Tupe, M.D., Bruce D. Gehle, J.D., and William J. Brady, M.D. N Engl J Med 2015; 373:939-945.September 3, 2015 DOI: 10.1056/NEJMra1409213. Available for purchase online from: http://www.nejm.org/doi/full/10.1056/NEJMra1409213
Travelling overseas? Discuss your travel plans with a travel health specialist by calling 1300 360 164 to book a consultation at your nearest Travelvax Australia clinic. Any vaccines or travel medications that might be required or recommended can be provided during your visits.