Talk to club in November 2011

1. FLYING WITH CPAP
Derek Figurski - Laboratory Manager
Acknowledge Ms Leigh Seccombe from Concord Repatriation Hospital NSW

2. The scope of air travel
942 ft or 290 m
Torino, Italy

3. A risky intersection?
 Every day, over 16 000 Australians
travel overseas and there are
120000 domestic passenger
movements1
 Estimated that up to 5% of middle
age men & women in the general
population have Obstructive Sleep
Apnoea (OSA)2
 Guidelines have been published to
assist physicians and patients with
lung disease and air travel3&4
 How has commercial airlines
adopted these guidelines, in
Airports Council International. World Traffic Report 2007 particular with CPAP usage?

4. The aircraft environment
5315 ft or 1620 m
Zermatt,
Switzerland

5. Modern aircraft
 Cruise altitude ~ 28 – 41 000ft (8500 – 12 500m) above sea level
 Long haul flights up to 20 hours (A380 and Boeing 747 Dreamliner)
 Cabin air pressure falls as an aircraft ascends to cruising altitudes

6. Cabin Environment Cocktail
 Pressurised with compressed ambient air taken from the intakes
of the jet engines (superheated)
 A small risk of contamination with fumes from engine lubricants
 Add some recirculated air (filtered) without which cabin humidity
would be intolerably low
 Minimal risk of microbial contamination from new cabin air
http://www.boeing.com/commercial/cabinair

7. Federal aircraft regulations
 Balance of passenger safety/comfort vs. operating costs
 Federal Aviation Administration (FAA) regulations*
 Lowest cabin pressure = 76 kPa
 This is equivalent to 2400m (8000 ft) above sea level,
 This creates two issues:
 First, gas within a closed cavity, such as the middle ear, sinuses,
a poorly communicating bulla or a pneumothorax, will expand
 Second, the falling pressure causes an equivalent fall in inspired
oxygen levels
 This degree of low oxygen levels is well tolerated and is not
associated with any adverse effects
*Code of Federal Regulations Title 14, part 25.841
Washington

8. The two issues……
 Relationship between altitude  Atmosphere oxygen levels at
and pressure sea level and at altitude
 Relationship between altitude  Oxygen levels in the blood at
and trapped air sea level and at altitude
25% of sea level
pressure

9. The cabin environment
 What is the oxygen level?

10. The cabin environment
 % of oxygen in room air at sea level = 21%
(fraction of inspired oxygen – FIO2)
 % of oxygen at 2400 m = 15%
Mt
Kosciusko
7310 ft or
2229 m

11. Are all flights the same?
7710 ft or 2350 m
Macchu
Picchu
Peru

12. Typical long-haul flight
“Typical” Long-haul
B747*
17%O2
Sydney to Los Angeles
 Cabin altitudes are always below 2400 m, average of 1830 m5
 Aircraft may not reach higher cruise altitudes for many hours due to
the need for the flight to achieve appropriate altitude
 Lowest oxygen levels at the end of a long flight

13. Typical short-haul flight
“Typical” short-haul A320*
Brisbane to Melbourne
15%O2
 Ascent and descent to cruise altitude may both take 20 minutes
 Period at cruise altitude is quite short – may be only 40 minutes
 Cabin altitude may get close to 2400 m but the period of risk is quite
short

14. The effect on our oxygen levels
9086 ft or 2770 m
Telluride,
Colorado

15. The normal response
 The physiological hazard
 Low oxygen
 Low humidity (10-15%)
 Low activity
Altitude FIO2 PB PIO2 FIO2 % PaO2 SpO2
(ft) (%) (mmHg) (mmHg) (sea level) (mmHg) (%)
0 21 760 159 21 >80 >95
Sea Level
8000 21 565 108 15.1 ≈ 60-70 >90
Max Cabin

16. The normal response
 The physiological hazard
 Low oxygen
 Low humidity (10-15%)
 Low activity
Altitude FIO2 PB PIO2 FIO2 % PaO2 SpO2
(ft) (%) (mmHg) (mmHg) (sea level) (mmHg) (%)
0 21 760 159 21 >80 >95
Sea Level
8000 21 565 108 15.1 ≈ 60-70 >90
Max Cabin

17. The OSA response to altitude
 One of the hallmarks of severe OSA is repetitive oxygen
desaturation (represented by SpO2)
 Long haul flights may increase the risk of low SpO2, perhaps
reflecting a gradual fall in cabin oxygen pressure.
 Historically outcome data at altitude for this group of patients are
limited and conflicting in nature
 OSA patients with significantly low SpO2 at sea level would be
expected to have more profound drop in SpO2 during apnoeic
periods at high altitude, but there are no data on this issue
 But if we look at patients with OSA performing the High Altitude
Simulation Test (HAST)……..

18. OSA O2 Response
 Recent study5 investigated the degree of low oxygen levels in
untreated OSA (n = 15) vs. treated OSA (n = 14) performing a HAST
(FIO2 = 15.1%)
 Positive test for in flight supplemental oxygen is a PaO2 fall below
50mmHg (<6.6 kPa) or the SpO2 falls below 85%3

19. HAST the Flight Simulator
Actual cabin altitude and in-flight SpO2 on a study subject6
HAST SpO2 range (15 to 20 min) presented on the y2-axis

20. Results5
 Results indicated that both groups had significant drop in SpO2 on
the HAST with reported side effects (headache & light-headedness)
 4/15 untreated OSA group had a positive test
 None of the treated OSA had a positive test
 Treated OSA showed a pattern of less severity in oxygen
desaturation
Untreated OSA (AHI ≥ 10/h) Treated OSA CPAP (AHI ≤ 10/h)
for 6 weeks (≥ 4hr/night usage)

21. In summary
 A lower oxygen environment is present on aircraft than at sea level,
but there are minimal adverse effects
 Different aircraft types have varying cabin pressures, but airlines
need to adhere to regulations stipulated by government bodies
 The affects of long haul flights on OSA patients is unknown
 Limited evidence suggests OSA can be an additional risk for
developing significant in flight hypoxaemia (low SpO2) similar to
COPD & ILD
 Further research is needed to assess the physiological responses
of OSA at altitude for prolong periods
 Limited evidence to date shows there is possible benefit to using
CPAP (6 weeks) prior to exposure at altitude
 Patients with obstructive or central sleep apnoea at sea level
should travel to high altitude with their CPAP equipment

22. CPAP with Air Travel
9222 ft or 2812 m
Quito,
Ecuador

23. Preparation prior to flight
 A doctor’s letter is required outlining the diagnosis and necessary
equipment. It should state that the continuous positive airway
pressure (CPAP) machine should travel in the cabin as extra hand
luggage (some airlines treat this as excess luggage)
 A fact sheet for passengers to show airport security personnel in
the USA is available from the American Sleep Apnea Association
(www.sleepapnea.org)
 Policies vary on the use of CPAP while flying and passengers
need to contact the airline directly
 Recent survery7 of 53 airlines in January 2008 servicing Australia
& New Zealand reported:
 28 (53%) permitted the use of CPAP machines during flight
 9 (17%) did not permit the use of CPAP
 16 (30%) were unable to ascertain their policies

24. Inconsistent Policy……
Survey was
23 (82%)
completed by 1
required a
representative
standard
of the airline
form to be
completed

25. Example
 Clearance Form
http://www.qantas.com.au

26. Also worth considering….
 All 28 airlines required to bring their own CPAP machine and dry
cell batteries
 Not all plug-in are available on all airplanes in the fleet (6 airlines)
 Dry cell batteries should meet manufacturer's specification and
packed according to airline’s recommendation
 Supply of batteries adequate for 1.5 times the flight duration
 Inconsistent information on current and voltage requirements with
only 4 airlines able to provide information on adaptors –
Qantas, British Airways, Cathay Pacific & South African Airlines
 Air New Zealand only allows a US plug and no adaptor
 Notification to airlines if passenger will be using CPAP during flight
ranged from 2 days (46%) with a further 25% requiring 7 – 14 days
 Remember to enjoy your flight!

27. CPAP Pitfalls in Flight
Mauna Lau,
Hawaii
3059 m

28. Just a few…..
 AC power is not usually available on board and passengers should
use dry cell batteries; dry cell battery-powered CPAP can be used
throughout except during take-off and landing
 Power supplies are not available on all flights, sockets may not be
available at every seat and, even if available, not all airlines allow
them to be used for such equipment
 Airlines do not always provide an appropriate adaptor and older
machines may not be compatible with the power supply
 Some CPAP machines can be powered from a direct current while
others require an inverter
 Dry batteries are heavy and will only power a CPAP machine for a
limited time

29. Not enough pressure Captain!
 CPAP machines used in-flight should be capable of performing
adequately in the low pressure cabin environment
 As noted above, if the equipment does not have pressure
compensating features, a higher level of pressure will be necessary
during the stay at simulated high altitude (cabin environment)
 Calculations based on the collective fan laws and measurements
made in a hypobaric chamber have shown that a fixed-pressure
CPAP machine without pressure compensation set to deliver a
pressure of 12 cm H2O at sea level may deliver only 9 cm H2O at
8000 ft 3
 Machines with pressure sensors can deliver accurate pressures
across a range of pressure/altitude combinations

30. General Advice
12002 ft or 3659 m
Lhasa, Tibet

31. CPAP usage
 Alcohol and sedatives should be avoided before and during travel
 Possible further exacerbation of jetlag symptoms with no usage
 Patients may wish to drive or work soon after overnight flights;
evidence suggests that withdrawing CPAP for just 1 day may cause
sleepiness8
 Arrange medical insurance
 Choose a machine approved by the FAA
 Provide the airline information about the physical size, make and
model of your machine when applying
 Check in early…
 Always review airline websites for up to date information
 Air travel recommendations for Europe:
www.european-lung-foundation.org
 If unsure of advice given, seek an alternative within the airline

32. Concluding Remarks
13310 ft or 4058 m
La Paz,
Bolivia

33. Conclusion
 Your oxygen levels will be lower in-flight
 If you remember that risk of adverse events is minimal with flight
 You may experience even lower oxygen levels while asleep due to
your sleep apnoea and CPAP is recommended
 You need to talk with your physician about the risk of not using
CPAP on long haul flights
 In addition seek advice if you are staying at your holiday
destination if at altitude for a long period of time
 Plan well in advance and check airline websites for up to date
information on the guidelines for CPAP usage
 Know your CPAP machine and seek advice from manufacturers or
local supplier
 Enjoy travelling and additional stopovers have benefits!

34. Questions
Hopefully airlines follow
their own guidelines!

35. References
1. Seccombe LM & Peters MJ, Patient with Lung Disease – Fit to Fly,
Australian Family Physician, Vol. 39, No. 3, MARCH 2010
2. Young T et al, Epidemiology of OSA, Am J Respir Crit Care Med, Vol
165. pp 1217–1239, 2002
3. Coker RK et al, Managing passengers with stable respiratory disease
planning air travel: British Thoracic Society recommendations, Thorax,
Vol. 66: i1ei30 2011
4. Aerospace Medical Association. Medical guidelines for air travel, 2nd
edn. Aviat Space Environ Med 2003;74(Suppl 5): A1e19
http://www.asma.org/
5. Ali, M et al, Hypoxic challenge assessment in individuals with OSA,
Sleep Medicine, Vol. 12, pp158–162 2011
6. Kelly, PT et al, Air Travel Hypoxemia vs the Hypoxia Inhalation Test in
Passengers With COPD, Chest Vol. 133 / 4 / APRIL, 2008
7. Walker, J et al, Airline policies for passengers with OSA who require in-
flight CPAP, Respirology, Vol. 15, pp 556 – 561 2010