Recently updated evidence-based guidance addresses the particular problems that flying can present for patients with respiratory problems, as Dr Robina Coker explains

The British Thoracic Society (BTS) first published recommendations for managing passengers with respiratory disease who are planning air travel in 2002.1 The guidance was prepared in response to a national survey of respiratory physicians,2 which revealed wide variation in how such patients were assessed and managed, and gave general support for more formal advice.

The recommendations included a consensus document drawn up by the BTS Air Travel Working Party in the light of available evidence, directions for future research, a patient information leaflet and an information leaflet for GPs. The document aimed to provide practical advice for respiratory physicians working in a hospital setting managing passengers on commercial flights. It was not intended to apply to airline staff or emergency repatriation.

In 2004, the BTS, following its practice of updating guidelines every 2 years, published updated recommendations, 3 and the review enabled the Air Travel Working Party to examine new evidence.

In practical terms, the most significant changes are those affecting patients with pneumothorax, but there are also welcome developments for frequent fliers with medical needs, and further evidence supporting the 2002 recommendations on prevention of venous thromboembolism in high-risk patients. A number of changes are relevant to GPs and the primary healthcare team.

The flight environment and effects of altitude

The introduction of the new Airbus 380 is highlighted. This aircraft is capable of carrying as many as 800 passengers for periods of up to 20 hours or more.

There is a greater likelihood of medical incidents occurring on longer flights, and the possible effects of prolonged periods of exposure to cabin pressures equivalent to altitudes of around 2438 m (8000 ft) are unknown.

Altitude exposure can affect patients with bullous lung disease; however, there is uncertainty regarding the risk of air travel for individuals with large bullae, and a specialist respiratory opinion should be sought for these patients.

Pre-flight assessment

Assessment of adults

Procedures for assessing adults before air travel are unchanged. However, new recommendations have been added on Severe Acute Respiratory Syndrome (SARS). The advice follows that published as a consensus statement by the World Health Organization.4

The important points to note are that passengers from an area with recent local transmission of SARS and symptoms compatible with SARS should not travel on commercial flights, and neither should individuals who have been in contact with probable or confirmed SARS cases during the preceding 10 days.

Assessment of children

The recommendations on the preflight assessment of children have been altered in the light of data from the Brompton Hospital.5 For children with cystic fibrosis or other chronic lung disease and FEV1 <50% predicted, pre-flight assessment, including hypoxic challenge testing, is now advised. If SpO2 then falls below 90%, supplementary in-flight oxygen is recommended. Most of these patients are likely to be already under the care of a respiratory specialist.

Travelling with oxygen

Some airlines now prohibit the use of supplementary in-flight oxygen during take-off and landing, and this may prevent a small number of individuals travelling by air.

International regulations relating to portable oxygen cylinders have been clarified. Patients are permitted to use their own oxygen on board aircraft and to carry full, small oxygen cylinders with them for medical purposes as hand baggage, provided they have the approval of the airline concerned. Passengers must check with the airline first, and a charge may be made.

Frequent traveller’s medical card

It is important for passengers to arrange adequate medical insurance. However, a welcome development is that patients who travel frequently and have particular medical needs can obtain a frequent traveller’s medical card (FREMEC), issued by airline medical departments.

The card contains important medical information and replaces forms that previously had to be completed for each flight. Once a patient has registered, the airline’s reservations office records details of his or her requirements so that special assistance can be arranged whenever the patient flies. The period of validity depends on the nature of the condition.

The card is issued by many airlines, but if a patient chooses to fly with an airline other than that which issued the card they should check its validity with the new airline.

Specific conditions

Asthma

From April 2004, all aircraft flying to and from the USA are required to carry bronchodilator inhalers as part of their medical kit. Requirements on all other flights vary.

Down’s syndrome

A study of children with Down’s syndrome suggests that it is prudent to carry out a careful evaluation of these patients before they travel by air.6

The authors found that children with Down’s syndrome (aged 3-6 years) were at risk from high altitude pulmonary oedema within 24 hours of arriving at altitudes of 1738-3252 m, especially if they were suffering, or had recently suffered, an upper respiratory tract infection.

Patients requiring ventilation

The recommendations note that airlines may insist on any ventilator being switched off for take-off and landing. For patients requiring permanent (24-hour) ventilation, this means that a medical escort competent to ventilate the patient by hand for up to an hour is absolutely essential.

Pneumothorax

The previous recommendation to wait 6 weeks after resolution of pneumothorax before travelling – the ‘6-week rule’ – has been discarded. The guidance now stipulates that after spontaneous pneumothorax patients must have a chest X-ray confirming resolution before flying, and recommend that at least a further week should elapse before travel.

Cases of traumatic pneumothorax and air travel have attracted considerable publicity. A study of 12 patients planning air travel after recent traumatic pneumothorax showed that 10 who waited at least 2 weeks after resolution on chest X-ray were asymptomatic during flight. One of the remaining two patients who flew within 14 days developed respiratory distress during flight.7

After traumatic pneumothorax, therefore, the 2004 recommendations advise a 2-week wait before air travel following evidence of full resolution on chest X-ray.

Venous thromboembolism

The 2004 update continues to support House of Lords guidelines on venous thromboembolism (VTE).8 Further evidence supports the use of low molecular weight heparin in patients at high risk of VTE.9 Some 300 individuals at high-risk were randomly assigned to receive no prophylaxis, aspirin for 3 days or low molecular weight heparin between 2 and 4 hours before flying.

In 82 controls, the incidence of deep vein thrombosis (DVT) was 4.8%,compared with 3.6% in 84 who received aspirin. There were no episodes of DVT in the 82 individuals who took low molecular weight heparin.

Some 85% of DVTs occurred in individuals sitting in non-aisle seats, supporting advice to remain as mobile as is practicable during flight.

Box 1 (below) gives passengers’ level of risk and the advice they should be offered.

Box 1: Airline passengers at risk of venous thromboembolic disease
Risk status Risk factors Advice
All passengers Low Avoid excess alcohol and caffeine-containing drinks
Remain mobile/exercise legs
Slightly increased Aged over 40
Extensive varicose veins Polycythaemia
Within 72 hours of
minor surgery
Above plus consider:
Take short periods of sleep
Support hosiery
Moderately increased Family history of VTE
Recent MI
Pregnancy or early post-natal period
Oestrogen therapy
Limb trauma or paralysis
Above plus consider:
Pre-flight aspirin
Graduating compression stockings
High risk Previous VTE
Thrombophilia
Within 6 weeks of major surgery
Previous stroke
Current malignancy
Avoid flying or recommend low molecular weight heparin or formal anticoagulation (including return journey)

Conclusion

The most significant changes to the updated guidelines affect patients with pneumothorax, and frequent fliers with medical needs. The removal of the empirical ‘6-week rule’ is welcome, and will allow more patients to fly safely without unnecessary delay. Frequent fliers with long-term respiratory conditions should benefit from the FREMEC card.

The recent evidence supporting the use of low molecular weight heparin to prevent venous thromboembolism in high-risk patients will give them and their physicians increased confidence in an effective approach to making air travel safer.

References

  1. British Thoracic Society Standards of Care Committee. Managing passengers with respiratory disease planning air travel: British Thoracic Society recommendations. Thorax 2002; 57: 289-304.
  2. Coker RK, Partridge MR. Assessing the risk of hypoxia in flight: the need for more rational guidelines. Eur Respir J 2000 15: 128-30.
  3. Managing passengers with respiratory disease planning air travel. British Thoracic Society recommendations 2004. www.britthoracic. org.uk
  4. Consensus document on the epidemiology of severe acute respiratory syndrome (SARS). WHO/CDS/CSR/GAR/2003.11
  5. Buchdahl RM, Babiker A, Bush A, Cramer D. Predicting hypoxaemia during flights in children with cystic fibrosis. Thorax 2001; 56: 877-9.
  6. Durmowicz AG. Pulmonary edema in 6 children with Down syndrome during travel to moderate altitudes. Pediatrics 2001; 108: 443-7.
  7. Cheatham ML, Safcsak K. Air travel following traumatic pneumothorax: when is it safe? Am Surg 1999; 65: 1160-4.
  8. Deep vein thrombosis, seating and stress. In:Air Travel and Health. House of Lords Select Committee on Science and Technology Report 2000: 44-50.
  9. Cesarone MR, Belcaro G, Nicolaides AN et al. Venous thrombosis from air travel:the LONFLIT3 study - prevention with aspirin vs low-molecularweight heparin (LMWH) in high-risk subjects: a randomized trial. Angiology 2002; 53: 1-6.

Guidelines in Practice, May 2005, Volume 8(5)
© 2005 MGP Ltd
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