The Effect of Sudden Depressurization on Pilots at Cruising Altitude

  • Thomas Muehlemann
  • Lisa Holper
  • Juergen Wenzel
  • Martin Wittkowski
  • Martin Wolf
Conference paper
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 765)


The standard flight level for commercial airliners is ∼12 km (40 kft; air pressure: ∼ 200 hPa), the maximum certification altitude of modern airliners may be as high as 43–45 kft. Loss of structural integrity of an airplane may result in sudden depressurization of the cabin potentially leading to hypoxia with loss of consciousness of the pilots. Specialized breathing masks supply the pilots with oxygen. The aim of this study was to experimentally simulate such sudden depressurization to maximum design altitude in a pressure chamber while measuring the arterial and brain oxygenation saturation (SaO2 and StO2) of the pilots. Ten healthy subjects with a median age of 50 (range 29–70) years were placed in a pressure chamber, breathing air from a cockpit mask. Pressure was reduced from 753 to 148 hPa within 20 s, and the test mask was switched to pure O2 within 2 s after initiation of depressurization. During the whole procedure SaO2 and StO2 were measured by pulse oximetry, respectively near-infrared spectroscopy (NIRS; in-house built prototype) of the left frontal cortex. During the depressurization the SaO2 dropped from median 93% (range 91–98%) to 78% (62–92%) by 16% (6–30%), while StO2 decreased from 62% (47–67%) to 57% (43–62%) by 5% (3–14%). Considerable drops in oxygenation were observed during sudden depressurization. The inter-subject variability was high, for SaO2 depending on the subjects’ ability to preoxygenate before the depressurization. The drop in StO2 was lower than the one in SaO2 maybe due to compensation in blood flow.


Depressurization High altitude Near-infrared spectroscopy Pilot Tissue oxygen saturation 



The investigations described here were performed in conjunction with a study supported by Airbus Germany and Zodiac Oxygen Systems, France.


  1. 1.
    Muehlemann T, Haensse D, Wolf M (2008) Wireless miniaturized in-vivo near infrared imaging. Opt Express 16(14):10323–10330CrossRefGoogle Scholar
  2. 2.
    Quaresima V, Ferrari M, Torricelli A et al (2005) Bilateral prefrontal cortex oxygenation responses to a verbal fluency task: a multichannel time-resolved near-infrared topography study. J Biomed Opt 10(1):11012CrossRefPubMedGoogle Scholar
  3. 3.
    Tisdall MM, Taylor C, Tachtsidis I et al (2009) The effect on cerebral tissue oxygenation index of changes in the concentrations of inspired oxygen and end-tidal carbon dioxide in healthy adult volunteers. Anesth Analg 109(3):906–913CrossRefPubMedGoogle Scholar
  4. 4.
    Wolf M, von Siebenthal K, Keel M et al (2000) Tissue oxygen saturation measured by near infrared spectrophotometry correlates with arterial oxygen saturation during induced oxygenation changes in neonates. Physiol Meas 21(4):481–491CrossRefPubMedGoogle Scholar
  5. 5.
    Choi J, Wolf M, Toronov V et al (2004) Noninvasive determination of the optical properties of adult brain: near-infrared spectroscopy approach. J Biomed Opt 9:221–229CrossRefGoogle Scholar
  6. 6.
    Bale SJ, Amos CI, Parry DM et al (1991) Relationship between head circumference and height in normal adults and in the nevoid basal cell carcinoma syndrome and neurofibromatosis type I. Am J Med Genet 40(2):206–210CrossRefPubMedGoogle Scholar
  7. 7.
    Lynnerup N (2001) Cranial thickness in relation to age, sex and general body build in a Danish forensic sample. Forensic Sci Int 117(1–2):45–51CrossRefGoogle Scholar
  8. 8.
    Wallace D, Barbieri B, Hintz SR (2000) Neonatal cerebral oxygenation measurements and the effects of curvature on frequency domain multiple distance near infrared spectroscopy. In Biomedical Optical Spectroscopy and Diagnostics. Lit (ed) Vol 38 of OSA Trends in optics and photonics, paper SuF1.
  9. 9.
    Tachtsidis I, Tisdall M, Delpy DT et al (2008) Measurement of cerebral tissue oxygenation in young healthy volunteers during acetazolamide provocation: a transcranial Doppler and near-infrared spectroscopy investigation. Adv Exp Med Biol 614:389–396CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Thomas Muehlemann
    • 1
  • Lisa Holper
    • 1
  • Juergen Wenzel
    • 2
  • Martin Wittkowski
    • 2
  • Martin Wolf
    • 1
  1. 1.Biomedical Optics Research Laboratory, Division of Neonatology, Department of Obstetrics and GynecologyUniversity Hospital ZurichZurichSwitzerland
  2. 2.Department of Flight PhysiologyDLR-Institute of Aerospace MedicineCologneGermany

Personalised recommendations