Air travel can affect passengers with lung diseases due to the lower oxygen levels at cruising altitudes. The document discusses the effects of altitude on lung physiology and provides guidelines for assessing fitness to fly for patients with respiratory conditions like COPD, cystic fibrosis, lung cancer, and pneumothorax. Clinical tests like walk tests, hypoxic challenge tests, and equations can predict the risk of hypoxemia during flights. Advice is given on managing specific lung conditions during air travel, including the use of supplemental oxygen and medications.

1. AIR TRAVEL AND
LUNGS
DR ANUSHA CM

2. INTRODUCTION
• Each year worldwide, more than 2.75 billion
passengers travel by air
• One study reports that over an approximately 3-
year period, there were 11,920 in-flight medical
emergency calls made by airlines to a medical
communications center; this was estimated to
represent almost 1 medical emergency for every
600 flights
• Respiratory symptoms accounted for 12% of these
in-air emergencies. The development of respiratory
symptoms during flight was associated with an
increased risk of hospitalization after air travel

3. • One direct consequence has been that doctors are
frequently asked by respiratory patients: ”Can I fly
safely with my lung problems?”
• A brief overview of air travel for patients with lung
disease, including physiology, guidelines, assessing
fitness to fly and oxygen supplementation.

4. The flight environment and effects of
altitude
• Commercial air craft are pressurized to cabin
altitudes of upto 8000 ft (2438 m)
• Pressurization of the aircraft cabin achieved using
exterior air that is compressed and mixed with
filtered and recirculated cabin air.
• Up to 50% of the cabin air is not recirculated and is
expelled, to be replaced with exterior air, with 20–
30 complete air exchanges occurring per hour
• FEV1 to predict hypoxaemia or complications
accurately during or after air travel in patients with
respiratory disease

6. High-altitude physiology
• The sigmoid shape of the oxygen dissociation curve
allows healthy individuals to ascend to moderate
altitude (~2,400 metres or 8,000 feet) without any
appreciable hypoxaemia
• Beyond this altitude, the fall in alveolar PO2 is
steep and significant hypoxia will quickly develop.
• Patients with respiratory disease may have a
rightward shift in the oxygen dissociation curve due
to chronic respiratory acidosis, which will result in a
decreased affinity of haemoglobin for oxygen,
increasing the possibility for the development of
desaturation.

8. • In respiratory patients, desaturation may occur if
there is a blunted ventilatory response to hypoxia,
either due to chemoreceptor insensitivity, airway
obstruction limiting an increase in ventilation or
increased shunting in the lungs.

9. Consequences of Hypobaric Hypoxia
and Compensatory Mechanisms
• At 8,000 feet, the reduced barometric pressure and
decreased partial pressure of oxygen = to breathing
air that contains approximately 15.1% of oxygen
while at sea level.
• Forms the basis of the normobaric hypoxic
challenge test, and results in a partial pressure of
inspired oxygen of 100–105 mm Hg and partial
pressure of arterial oxygen (PaO2) of approximately
60–70 mm Hg in healthy individuals

10. • In expiratory flow– limited patients, an increase in minute ventilation may result
in hyperinflation, and further exacerbate respiratory discomfort
• Other conditions contributing to high-altitude hypoxemia and in-flight
complications include ILD, OSA , pulmonary hypertension, pneumothorax, and
cystic fibrosis

13. Pre-flight assessment for adults
• It is recommend that those with the following
conditions should be assessed with history and
examination as a minimum:
• Previous air travel intolerance with significant
respiratory symptoms (dyspnoea, chest pain,
confusion or syncope).
• Severe COPD (FEV1 <30% predicted) or asthma.
• Bullous lung disease.
• Severe (vital capacity <1 litre) restrictive disease
(including chest wall and respiratory muscle
disease), especially with hypoxaemia and/or
hypercapnia.

14. • Cystic fibrosis.
• Comorbidity with conditions worsened by
hypoxaemia (cerebrovascular disease, cardiac
disease or pulmonary hypertension)
• Pulmonary tuberculosis.
• Within 6 weeks of hospital discharge for acute
respiratory illness.
• Recent pneumothorax.
• Risk of or previous venous thromboembolism.
• Pre-existing requirement for oxygen, CPAP or
ventilator support.

15. Contraindications to commercial air
travel
• Infectious tuberculosis.
• Ongoing pneumothorax with persistent air leak.
• Major haemoptysis.
• Usual oxygen requirement at sea level at a flow rate
exceeding 4 l/min.

16. Clinical tests
1. Walk tests
• The ability to walk 50 m without distress
• Advantage - simple
• Disadvantage - not verified, crude
• The ability to increase minute ventilation and
cardiac output in response to an exercise load is a
good test of cardiorespiratory reserve

17. 2. Predicting hypoxaemia from
equations
• Use of several equations predicting PaO2 or SpO2 from
sea level measurements.
• Derived almost exclusively from patients with chronic
obstructive pulmonary disease (COPD) who have had
PaO2 measured in a hypobaric chamber, or before and
during exposure to simulated altitude while breathing
15% inspired oxygen from a reservoir bag
• 20.38- (3 x altitude) + 0.67x PaO2 Ground (mmHg)
• 22.8 – (2.74 x Altitude) + 0.68 x PaO2 Ground (mmHg)
• Flight duration and cabin conditions are obviously not
reproduced.

18. 3. Hypoxic challenge test (HCT)
• The easiest method is for the patient to breathe a
hypoxic gas mixture (commonly referred to as a
hypoxic challenge which will replicate the PO2
experienced in a pressurised commercial airliner
• Hypoxic challenge can be carried out using a
specially prepared gas mixture either from a gas
cylinder or by utilising a Douglas bag, which acts as
a reservoir for the hypoxic gas mixture that a
patient breathes from using a non- rebreathing
valve

19. PaO2 levels measured by HIT correlated with PaO2 levels
measured with hypobaric exposure of 8000 ft.

20. -2011

22. Hyperbaric chamber

23. Respiratory disorders with potential
complications for air travellers
1. Airways disease (asthma and COPD)
• For an A/E on board, bronchodilator inhaler
should be administered, with a spacer and the dose
repeated until symptomatic relief is obtained
• Patients with severe or brittle asthma or severe
COPD (FEV1 <30% predicted) - emergency use of
prednisolone

24. 2. Cystic fibrosis
• In children with CF or other chronic lung diseases
who are old enough for spirometry and whose
FEV1 is <50% predicted, HCT is recommended.
• If SpO2 falls below 90%, in-flight oxygen advised
3. Non-CF bronchiectasis
• Nebulised antibiotics and nebulised
bronchodilators should not be required

25. 3. Cancer
• Severe or symptomatic anaemia ,hyponatraemia,
hypokalaemia and hypercalcaemia – to be
corrected before travel
• Treatment (radiotherapy, chemotherapy and/or
stenting) for major airway obstruction, including
upper airways stridor to be complete before travel
• Lymphangitis carcinomatosa or superior vena caval
obstruction patients should only fly if essential, and
have in-flight oxygen available
• Pleural effusions to be drained as much as possible
before travel

26. 4. Hyperventilation and dysfunctional
breathing
• Full assessment before travel and appropriate
breathing modification exercises and/or
pharmacotherapy to be started before travel
• Rebreathing techniques may be used for acute
hyperventilation
• Evaluation of response to rapidly acting anxiolytics
is advised before travel

27. 5. Tuberculosis
• The prevalence of adults with active TB on long-
haul air flights is estimated at 0.05 per 100000
long-haul passengers.
• In none of the studies was transmission of clinically
active TB reported.
• TB transmission was defined as a positive TST in the
absence of any risk factors for TB.
• Associations with TB transmission- longer flights
and seating in close proximity to the index case.

28. • While in- flight TB transmission , there is no greater
risk of TB transmission during air travel compared
with other modes of transport.
• Contact tracing is time and resource consuming
and, to date, no cases of active TB transmission
have been documented despite numerous contact
tracing investigations.
• Risk factors - productive cough and smear- positive
sputum, cavitating or laryngeal TB, flight time >8 h
and proximity to the index case

29. 6. Obstructive sleep apnoea syndrome
(OSAS)
• Alcohol and sedatives - avoided before and during
travel
• A/C power not usually available on board and
passengers should use dry cell batteries; CPAP used
throughout except during take-off and landing
• CPAP machines used in-flight should be capable of
performing adequately in the low pressure cabin
environment
• Ensure that their CPAP machine is compatible with
the altitude and power supply at their destination,
and that a power supply is within reach of the bed

30. 7. Pneumothorax
• Patients with a closed pneumothorax should not
travel on commercial flights (with the exception of
the very rare case of a loculated or chronic localised
air collection which has been very carefully
evaluated)
• Must have a chest x-ray to confirm resolution
before flight.
• In the case of a traumatic pneumothorax, the delay
after full radiographic resolution should be 2 weeks

31. BTS guidelines for air travel in
Pneumothorax

32. 8. Thromboembolism

35. 9. Pulmonary arteriovenous
malformations (pavms)
• Patients with PAVM with or without significant
hypoxaemia should be considered at moderately
increased risk of VTE
• Patients with PAVM with a previous VTE or embolic
stroke should receive a single dose of low
molecular weight heparin before the outward and
return journeys

36. • Patients with PAVM with severe hypoxaemia may
benefit from in- flight oxygen
• For patients with PAVM with a previous VTE or
embolic stroke in whom embolisation treatment is
planned, deferring long-haul non- medical flights
may be advisable until embolisation is complete

39. SUMMARY

40. THANK YOU AND HAVE SAFE FLIGHT !