The cabin environment and vulnerable individuals

7.42 Our deliberations on the aircraft cabin environment have revealed relatively few health concerns for the great majority who are in normal health. However, as the age and health spectrum of those travelling by air widens, more and more people are flying with pre-existing or previously unsuspected medical conditions, which might be compromised by the cabin environment. MedAire has also told us that there is some evidence that ill or injured passengers, who, if they were to be moved by air at all, might previously have been transported in air ambulances, are now being carried in airliners (p 249).

7.43 We are grateful to AsMA for the excellent commentary and discussion on pre-existing medical conditions which may be compromised by air travel that they submitted in evidence to us (p 198) - indeed, their publications were frequently referred to or cited in others' evidence. Valuable comments, information and suggestions were also received from some members of staff at the Imperial College School of Medicine (p 239), from Dr Matthews (p 248) and in material from the Aviation Health Institute[99], including lists of conditions which may either preclude flying or require special medical attention before and during flight. As noted in paragraph 8.42, there are also some useful specialist textbooks and other guides on medical conditions which affect fitness to fly.

7.44 Drawing on all that material, we give some general guidance for such vulnerable individuals in paragraphs 7.46-7.72, although this is no substitute for personal medical advice. Individuals with many of the conditions concerned will already be in close touch with appropriate specialists. Intending passengers with any doubts about their fitness to fly should discuss these matters with their medical advisers and with the airline (or its agents) at the earliest possible opportunity.

7.45 At the risk of stating the obvious, it is essential that those with known medication needs should take sufficient supplies for the journey and, unless they are certain about supplies at their destination, for their stay and return journey.

NOTIFICATION OF SPECIAL CIRCUMSTANCES

7.46 Intending air travellers, or their medical advisers if appropriate, should inform airlines at an early stage of any medical condition they have which may require a decision on their fitness to fly, and of any special requirements they may have in boarding, flight or disembarking. There is an IATA standard medical information form (MEDIF) available from travel agents and airlines for this purpose. The Form is in two parts - Part 1 to be completed by the passenger and/or the agent, and Part 2, when appropriate, to be completed by the passenger's medical adviser. The airline will decide whether it can accommodate the needs and thus accept the passenger, if necessary after further medical examination and certification of fitness to fly.

7.47 There is also a standard IATA card (FREMEC) for those who need frequent medical clearance by which their physical travel requirements (excluding medical requirements such as on-board oxygen supplies) can be registered in computer booking systems, to avoid the need for repeated submission of MEDIF forms.

7.48 It is not realistic to require airlines to accept as passengers everybody who might wish to fly, which is why aircraft are exempted from the requirements of the Disability Discrimination Act 1995 specifically pertaining to the transport of passengers, including means of access standards. Decisions on these questions are potentially sensitive and may give rise to complaints, the general handling of which we discuss in paragraphs 8.57ff. Airlines have, however, a commercial imperative as well as a wider social responsibility to make reasonable provision for people with disabilities. We applaud the improvements achieved through IATA noted in paragraph 3.23, and encourage the industry as a whole to keep the matter under continuing and positive review.

CARDIO-VASCULAR CONDITIONS

7.49 For those with heart or circulatory disorders, the reduced in-flight oxygen availability may lead to a state of hypoxia (lowered body oxygen levels) which may further jeopardise their health. Many people with cardio-vascular disease are able to compensate for flight-induced hypoxia by increased breathing and increased cardiac activity, but some are unable fully to cope and will develop symptoms unless they are given supplementary oxygen. All cardio-vascular disease patients should take professional advice before travelling. If it is considered that they may need extra oxygen, they should declare this to the airline, which will normally make the appropriate arrangements at small or no extra charge. (Passengers are not allowed to take personal oxygen supplies on board.) They should also declare any need for pre- and post-flight physical assistance.

7.50 There are some cardio-vascular conditions, sufferers from which should not travel by air without proper advice. These are largely associated with the recency or severity of the disorder, known complications or lack of stability, and significant hypoxia at ground level. Pre-flight advice and declaration is essential as the carrier has the right to refuse flight even to a ticket-holder. Consideration must also be given to the altitude of take-off and landing airports.

7.51 Patients with stable angina, stable congestive heart failure, asymptomatic valve disease, controlled hypertension, and most types of pacemaker, should be able to travel safely provided they continue their medication. This should also be the case for those with recent strokes, heart attacks or cardiac surgery when they have recovered and stabilised.

7.52 Predisposition to DVT may also be associated with some cardiovascular disorders, as noted in paragraphs 6.13ff.

RESPIRATORY DISEASE

7.53 The primary factor affecting most respiratory disorders is also the potential for hypoxia. Air travel must be considered as potentially risky for people with any condition which limits lung capacity. These will include bronchitis, bronchiectasis, emphysema, pulmonary hypertension, cystic fibrosis, interstitial lung disease, pleural effusion, pneumothorax and pulmonary infections. Some people with skeletal, neuromuscular or malignant disorders may also be at risk because of inability to enhance respiration in response to hypoxia.

7.54 Bronchial asthma is the commonest respiratory disorder amongst travellers, and those whose condition is severe, unstable or have recently required hospitalisation might be advised not to travel by air until their condition is well-controlled. All asthmatics should carry their standard medication with them on board, and should also consider taking emergency medication with them.

7.55 Many people with respiratory disorders are able to travel by air, particularly with pre-booked supplementary oxygen supplies, but all should take medical advice beforehand, and some should be formally examined and tested for fitness to fly.

EAR, NOSE AND THROAT CONDITIONS.

7.56 The most important factor affecting ear, nose and throat (ENT) conditions is the changing cabin pressure during ascent and descent, which may cause barotrauma as discussed in paragraphs 5.43 and 5.44. If any of the anatomical passageways between ears, sinuses (air cavities in the bones of the face and head), nose and throat are, or become, blocked during flight, discomfort, pain and tissue damage may occur. Ear-block and head pain are the commonest medical complaints associated with air travel, and most passengers who fly frequently will experience some ENT problems at times, particularly if they have recent or current common colds. Dry cabin air may also contribute adversely in some cases such as those who have recently undergone major ENT surgery.

7.57 Acute and chronic sinusitis, middle ear infections and recent ENT surgery are all potential reasons not to fly, but pre-flight treatment with antibiotics and decongestants, and waiting for an appropriate time after surgery, should enable most people to become fit to fly. In-flight use of local decongestants and moisturisers may also be helpful.

PREGNANCY AND INFANTS

7.58 Generally, the cabin environment presents no medical hazards to normal pregnancy. The Royal College of Obstetricians and Gynaecologists cited evidence of a slightly increased risk of miscarriage in cabin crew (p 279), but the airline Emirates said that this finding had not been replicated in later studies (p 229).

7.59 Flying while pregnant may be inappropriate for those with a history of miscarriage or premature delivery, severe anaemia, recent vaginal bleeding, pre-eclampsia, and a serious fear of flying. It would be a wise precaution for all pregnant intending passengers to seek professional health advice before booking their flight.

7.60 In the early stages of pregnancy, air-sickness might compound "morning sickness". In the later stages, cramped seating, narrow aisles, limited mobility, seat belts, gas-producing foods and general discomfort might cause physical problems, and the risk of DVT must be considered. Airlines will usually carry healthy pregnant passengers of up to 36 weeks' gestation. As Virgin Atlantic noted, pregnant cabin crew are usually grounded on declaration of pregnancy to avoid any occupational risks to them or to the foetus (p 107), especially from cosmic radiation (see paragraph 3.63).

7.61 Although new-born babies should be able to fly safely, it is prudent to wait a week or so before taking them on a flight in case of post-delivery problems that might not be apparent at first sight, such as certain congenital defects, metabolic abnormalities and post-natal infections. After this period, the cabin environment presents no general problems for infants, although their immature ENT function may cause problems during ascent and descent. Feeding should ameliorate any potential problems due to pressure changes.

FLYING AFTER SURGERY

7.62 Increasing numbers of people are flying soon after surgery. Indeed, as AsMA noted, it is not uncommon for people to fly to a destination for their surgery and return home by air soon afterwards (p 198). The important cabin environment factor which may affect post-surgical passengers is pressure change, although reduced oxygen availability may also be of concern (see paragraph 7.67).

7.63 Gases introduced into, or trapped inside, body cavities will undergo volume expansion on ascent, and reduction on descent. As noted in paragraph 5.43, this may cause problems after any surgical procedure, but is primarily a problem after abdominal, intestinal, cardiac, lung, ENT, eye and cranial surgery. In the majority of cases, flying must be postponed until the gases have dissolved or diffused and suture lines have healed. Surgeons should always provide the appropriate warnings and advice about flying too soon.

7.64 Patients who have recently undergone surgery for detached retina may be seriously affected by pressure changes and should take specialist advice.

7.65 Travellers with established colostomies are not at risk, but throughput may be raised because of pressure differentials between the gut and the outside of the body.

7.66 Travellers with encased limb fractures are at some risk from pressure changes because of the unyielding nature of the casing, and must take pre-flight advice.

7.67 While recent general anaesthesia does not preclude flying (any residual medication or effects clear rapidly), surgery and trauma invariably increase the body's oxygen requirements and post-operative patients may be unusually susceptible to the reduced oxygen in cabin air (see paragraphs 4.4ff). Delaying flight until recovery is complete, pre-booking oxygen supplies, or pre-flight assessment of fitness to fly, will ameliorate potential problems.

NEURO-PSYCHIATRIC DISORDERS

7.68 There is nothing about the aircraft cabin environment itself which should affect those passengers with pre-existing neurological or psychiatric disorders. However, as noted in paragraph 6.62, the discomfort and stress of air travel could cause latent or controlled abnormal tendencies to become overt. People who have disorders which are unstable or potentially incapacitating, or whose reactions to unusual and stressful environments are unpredictable, should carefully consider (with their medical advisers as appropriate) the potentially stressful nature of air travel and their fitness to undertake it.

7.69 People whose physical or mental abilities are impaired, those on controlling medication, those who have frequent or unpredictable seizures, those with relevant phobias, and those with psychotic or socially disruptive disorders should particularly take note of the nature of air travel. Physical constraints of the cabin environment, limited access to toilet facilities, potential mild hypoxia, air turbulence, air-sickness, fatigue, boredom, jet-lag, management of medication when travelling across different time zones, disturbed meal-times, and absence of normal supporting features of their home environment - all potentially compounded by the duration of the flight - may each or severally contribute to affecting adversely their already compromised neuro-psychiatric status.

7.70 The only people in this group who should not fly are those whose reactions could lead to behaviour which is unacceptable or unsafe for themselves or fellow passengers. Most others may be able to undertake air travel with suitable advice and calming medication - and, in particular, accompaniment by a knowledgeable companion.

OTHER CONDITIONS

7.71 There are very few other conditions which would render those who have them vulnerable because of the aircraft cabin environment itself. Decompression sickness in passengers who fly too soon after diving was discussed in paragraph 5.47. Three others are discussed here.

(a)  Severe anaemia from any cause, blood disorders such as sickle-cell disease and some leukaemias, and any other condition which reduces the oxygen-transporting capabilities of the blood are potential reasons not to fly. However, subject to pre-flight assessment and booking of oxygen supplies where appropriate, most sufferers should be able to travel by air.

(b)  People with some eye conditions, and those who wear contact lenses, may be particularly affected by the dry cabin air and may need to use "artificial tears" when flying. Patients needing regular medication with eye-drops such as those with glaucoma or conjunctivitis are not at risk provided they maintain their medication throughout flight.

(c)  Diabetes itself is not affected by the aircraft cabin environment. However, the disruption of the timing and nature of meals, and of strict medication dosing and scheduling, on long-haul flights (particularly across many time-zones), can present major challenges to the insulin-dependent diabetic and problems for others. The diabetic air traveller should obtain appropriate advice, and preferably written instructions to be kept on the person, before any flight.

IDIOSYNCRATIC REACTIONS

7.72 A remaining possibility is that of allergy or sensitivity to substances in the cabin. This was referred to in the Australian Senate BAe 146 Inquiry Report (see paragraph 2.14) as a possible cause of ill health arising from exposure to fumes and vapours from engine oil leaks. Such idiosyncratic reactions - in the aircraft cabin or elsewhere - are, by definition, unexpected and unpredictable. However, the possibility should be borne in mind in unexplained ill health closely associated with air travel, particularly if symptoms arise during or soon after flight.

In-flight medical emergencies

NATURE AND EXTENT

7.73 We received statistical details on the nature and extent of in-flight medical events from a number of sources (including airlines, trade organisations and professional bodies) and figures published by airlines and regulatory bodies were widely quoted in others' evidence. Unfortunately, some of the statistical reports were not comparable between sources because individual airline requirements for recording and reporting of incidents differ substantially: for example, British Airways reported in-flight medical incidents as occurring in 1 in 12,000 passengers (p 99), whereas Virgin Atlantic's reported incidence was 1 in 1,400 (p 107). The current diversity in collecting data on in-flight medical emergencies serves no-one's interests. We welcome the news that standardised reporting procedures will be introduced by the world's major airlines in the near future (Q 305).

7.74 Taking account of the overviews provided by AsMA, BATA and MedAire, a reasonable estimate of the incidence of medical events requiring professional intervention (including by cabin crew who are trained to deal with medical emergencies) is about 1 in 14,000 passengers, with an in-flight death rate of about 1 in 3 million passengers (pp 198, 104 & 249). Considering that nearly two billion passengers undertake air travel per year (see paragraph 2.1), it is no surprise that a substantial number of in-flight events occur that require medical intervention or that deaths occur in flight.

7.75 The great majority of medical incidents are minor complaints which are resolved on board. General aches and pains, headaches, fainting, gastro-intestinal upsets and respiratory symptoms are the most commonly reported. The much smaller number of serious medical problems are mainly associated with cardiac, lung and cerebral disorders, asthma and cancer; most sufferers have pre-existing disease. Some of these will lead to in-flight death, and some will require the aircraft to be diverted and landed at the nearest airport with access to major emergency medical facilities. Because of differing company policies, routes flown, medical equipment and expertise on board, and availability of ground advice by radio, diversion rates are very variable between airlines. From the evidence given by British Airways, Virgin Atlantic and BATA, there appear to be about five times as many diversions are there are deaths in flight (pp 99, 104 & 107).

MANAGEMENT OF EMERGENCIES

7.76 Many major domestic and international airlines have, as noted by Dr Edgington of the Royal Aeronautical Society, AsMA and airlines, chosen greatly to exceed the requirements noted in paragraph 3.53, providing substantial medical kits for use by health professionals and training their crews to a high level of competence in managing in-flight medical emergencies (pp 272, 198, 99 & 107). While the contents of kits carried vary widely between airlines and aircraft types, most now contain sufficient equipment and drugs to deal with a wide range of common medical emergencies. At the time of writing, the AsMA Journal is publishing a series of articles covering the kits carried by the world's major airlines. A number of the major international carriers now provide on-board automatic external defibrillators (AEDs) for use in cardiac arrest and train all or some of the cabin crew in their use. FAA has just issued a Notice of Proposed Rulemaking[100] that all large passenger-carrying aircraft carry AEDs and augmented emergency medical kits.

7.77 Bearing in mind the greater numbers and range of people travelling by air, we recommend the Government to upgrade the required minimum provision by UK carriers for medical emergencies to current "best practice" levels in relation to both crew training and medical emergency kits. The latter should include automatic external defibrillators (AEDs) on at least long-haul aircraft. Furthermore, we recommend CAA to work through JAA to secure similar improvements across Europe.

7.78 A number of major airlines have had arrangements for some years for ground-based health professionals to pass medical emergency advice to aircrew whilst in flight. New communication systems, including the establishment of tele-medicine links (transfer of medical data by radio), have enabled this to be improved rapidly. Ground-based consultant services are now becoming available. We received evidence from airlines (pp 107, 229 & 288) and from one such service provider, MedAire (p 249), about the efficacy of these enhancements to in-flight medical care. Contracted ground-based expert medical advice provides not only considerably improved services to passengers but, as BATA noted (p 124), may also save on airline operating costs by reducing the number of medical diversions. We recommend all long-haul airlines to consider engaging such ground-based specialist consultant services.

100   Aviation, Space, and Environmental Medicine 71:866, August 2000 Back