In-flight medical emergencies: an overview

Methods

I searched recent literature for published articles and also drew information from conference presentations.1^–3 Statistics were made available by Virgin Atlantic Airways.

The problems

Older, less healthy, passengers often wish to fly considerable distances, and they expect that the airlines will look after them should problems arise. Similarly, people with known illnesses or disability expect no discrimination and that special facilities should be provided to make their journeys possible.

Air travel can precipitate or contribute to medical problems in a number of ways, even in previously healthy travellers. The stress of getting to and through a modern airport may be considerable. Uncertainty due to delay compounds any anxiety and may mean that too long is spent drinking at the bar. Three quarters of medical emergencies occur while travellers are still on the ground.4

Once in the air the drop in pressure (the cabin is kept at the equivalent of 6000-8000 feet (1950-2400 m) altitude) causes 30% gas expansion, and less oxygen is available. Pain from middle ears and sinuses blocked by catarrh is common, especially on the descent. Decongestants, analgesics, and swallowing are all the doctor can offer. The effect on pneumothorax was well publicised when, on a flight from Hong Kong to London, Professor Angus Wallace relieved a tension pneumothorax with the aid of a catheter, coat hanger, and brandy bottle.5 The reduced partial pressure of oxygen should not affect the healthy passenger, but it may affect those with compromised cardiovascular or respiratory systems or blood disorders.6 Shortness of breath may be due to myocardial insufficiency or lung disease, or to hyperventilation, which can be helped by breathing into one of the readily available paper bags.

As the journey proceeds the dry cabin atmosphere irritates mucous membranes. Drinking extra fluid helps, but drinking alcohol has the opposite effect. The intoxicating properties of alcohol are enhanced at altitude and often contribute to “air rage,” as does the smoking ban in nicotine addicts.7 Time zone changes and altered meal times can result in insulin dependent diabetics becoming hypoglycaemic, though diabetic meals can be provided. Passengers on other strict drug regimens, such as for epilepsy, may also have problems, especially if they have packed their medication in the hold. Restricted space in most seats encourages musculoskeletal aches and venous stasis.8 Regular stretching exercises and walks to the toilets when the seat belt sign is extinguished are recommended. Scalds are quite frequent from hot drinks in a crowded area, and head injuries caused by items falling from overhead storage bins are quite common (6.3% of incidents reported by British Airways) (M Bagshaw, British Airways, personal communication). Finally, problems on the individual flight can cause medical emergencies: though rapid decompression of the cabin is thankfully rare, turbulence is much less so. One passenger was killed and 110 injured when a Boeing 747 suddenly dropped 1000 ft on a flight from Japan to Honolulu in December 1997.

Data collection

The size of the problem is not known and the risks involved are hard to estimate. Airlines have not been required to monitor medical incidents or notify a central register. Furthermore, there is no clear definition of an “incident” or “emergency,” and this leads to wildly inconsistent data. Does this definition include diarrhoea and vomiting, or a faint? These are the most common conditions in flight for which medical help is sought (M Bagshaw, personal communication).

In an attempt to rationalise data collection, the Airline Medical Directors Association agreed in November 1999 that the Aerospace Medical Association will collect data on in-flight medical incidents. The reporting system will be international and voluntary. The report forms are now available to airlines and a website is being set up to facilitate responses.

Diversion of planes for medical emergencies

Diversions for genuine medical emergencies depend on the routes operated and the location of airports with medical and aviation facilities. The increasing use of super widebodied and super longhaul aircraft is likely to further restrict choice. The commonest reasons for diversion in a recent US study were cardiac incidents (28%), neurological problems (20%), and food poisoning (20%).9 Other reports have cited severe and uncontrollable pain or bleeding, major injury with shock, impending birth, and uncontrollable mental disturbance. Virgin Atlantic Airways flights diverted eight times for such cases in 1998 and 10 times in 1999 out of over 28 000 flights in the two years. It is unfortunate that confidentiality prevents airlines from learning the outcome of all these cases, and audit must largely be based on the percentage of hospital admissions. The American study of 1132 in-flight emergencies showed that 173 patients (15%) were admitted to hospital, with an average stay of 2.8 days, and 15 patients (1.3%) died.9

Various figures are reported for in-flight deaths, in the range of one death per 1.5-4.7 billion passenger miles flown. 1 10 There is a suspicion, however, that death rates are underreported because of bad publicity and, as on the ground, the patient will sometimes not be declared dead until arrival at hospital.

Scope for prevention

Though most medical emergencies in the air happen unexpectedly it should be possible to avoid many by careful screening of passengers with pre-existing medical conditions. Unfortunately these often come to attention only when a passenger requests some extra facility (a stretcher or medical escort) or makes a medical declaration for holiday insurance. The information is usually provided on the IATA “Medif” form, a two part form that has to be filled in by both client and doctor. It is badly designed, and the information given is sometimes inadequate, which may make it difficult to assess if the patient is fit to fly. Virgin Atlantic Airways referred nearly 2000 such cases to me in 1999, the number having increased by 55% from 1246 in 1997 to 1759 in 1998. The only medical emergency causing diversion of which Virgin Atlantic Airways had any prior knowledge was a patient with epilepsy who failed to take the regular medication.

Sometimes a check-in supervisor suspects that a passenger is unwell and telephones the airline's medical adviser or MedAire for advice. This is always difficult to deal with at a distance, as the passenger is usually loath to abandon a trip on the basis of a telephone decision and few airports have a doctor available at short notice.

No criteria for refusing or accepting to carry a passenger are set in stone, but I provide guidelines for relevant airline staff which I constantly review and revise in the light of experience. Some advice on when it is safe to fly after an uncomplicated heart attack, for example, has variously been given as 10 days11 and 24 weeks unless supplemental oxygen is available.12 Trial by treadmill as a basis for the decision used to be suggested.13 New challenges such as the current concern over suspected “peanut allergy” also command attention. It is Virgin Atlantic's policy to refuse to carry women who are 34 or more weeks pregnant but short haul airlines can accept later stages. New babies are considered fit to fly 48 hours after a normal delivery provided the pregnancy was normal and the mother has a confirmation letter from her medical practitioner.

Medical liability

Despite this training, the announcement “Is there a doctor on board?” is often heard, and apparently one is available on between 8% and 86% of flights world- wide.14 One was not available when requested on Virgin Atlantic Airways flights only four times in 1997 and eight times in 1998. In the United Kingdom there is no legal duty for a doctor to offer assistance in an emergency, although the General Medical Council considers that such a duty exists. The question of legal liability for medical emergencies on board aircraft is confusing because the law varies from country to country. Several major airlines have now taken out insurance policies indemnifying doctors who come forward to help (and the Medical Defence Union now covers its members worldwide). However, a liability clause in the US Aviation Medical Assistance Act of 1998 should make these precautions unnecessary.15 This act lays down minimum standards for medical equipment on board; a legal duty for airlines to report in-flight medical emergencies and death; and legal protection for airlines and doctors in good Samaritan situations.

Conclusion

In-flight medical emergencies are likely to increase as air travel continues to expand and life expectancy lengthens. Provisions made by the airlines continue to improve in response to this demand and to changing medical technology and practices, but commercial, financial, and practical considerations have to be taken into account.

The role of the on-board doctor has never been easy, often working in isolation with limited facilities in a hostile environment. Recent changes in attitude by the airlines (particularly with respect to medical indemnity) and the availability of Medlink should make the task easier, safer, and more professionally rewarding for those who come forward to help and act within their normal capabilities.