Physiological Consequences of Rapid or Prolonged Aircraft Decompression: Evaluation Using a Human Respiratory Model

Wolf M. Physiological consequences of rapid or prolonged aircraft decompression: evaluation using a human respiratory model. Aviat Space Environ Med 2014; 85:466–72.

Background: Aircraft passengers and crew may be subjected to rapid or prolonged decompression to high cabin altitude when an aircraft develops a hole in the fuselage. The accepted measure of neurological damage due to the hypobaric hypoxia produced is the subjective ‘time of useful consciousness’ (TUC) measure, which is appropriate for pilots and crew who perform their given tasks, however, TUC is measured under conditions different than the decompression scenarios that passengers undergo in today’s aircraft. Methods: Ernsting proposed that prolonged exposure to alveolar O₂ pressures less than 30 mmHg (P₃₀) causes neurological damage. The current study proposes that a critical value of arterial O₂ saturation of 70% (S₇₀) can be used in place of P₃₀ and that this physiological measure is more suited for determination of hypobaric hypoxia in passengers. Results: The study shows the equivalence of model-predicted P₃₀ and S₇₀ values in the Ernsting-decompression scenarios. The model is also used to predict values of these physiological measures in actual aircraft-decompression scenarios. Discussion: The model can be used by others to quantitatively predict the degree of hypobaric hypoxia for virtually any kind of decompression scenario, including those where supplemental O₂ is used. Use of this tool avoids the prohibitive costs of human-subject testing for new aircraft and the potential danger inherent in such tests.