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Decompression-Related Disorders: Pressurization Systems, Barotrauma, and Altitude Sickness

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Principles of Clinical Medicine for Space Flight

The physiological zone from sea level to 3,048 m (10,000 ft) encompasses the pressure to which humans are well adapted, although if appropriately acclimated they can survive the summit of Earth’s highest mountain (Mt. Everest at 4,448 m/29,028 ft) without supplemental oxygen. Continuing to altitudes above this, artificial systems are required to supply needed oxygen and, eventually, sufficient ambient pressure. The most effective means of preventing physiological problems in aircraft and spacecraft is to provide cabin pressurization so that occupants are never exposed to pressures outside the physiological zone. Failure of structures, hardware, or procedures may unfortunately lead to unwanted and hazardous decompression events. This chapter will review cabin pressurization schemes, events that might lead to loss of pressure, and two major medical concerns of decompression: barotrauma and altitude sickness.

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References

  1. National Research Council (U.S.). Orbital Debris, A Technical Assessment. Committee on Space Debris. Aeronautics and Space Engineering Board. Commission on Engineering and Technical Systems. Washington, DC: National Academy Press; 1995.

    Google Scholar 

  2. National Research Council (U.S.). Protecting the Space Shuttle from Meteoroids and Orbital Debris. Committee on Space Shut-tle Meteoroid/Debris Risk Management. Aeronautics and Space Engineering Board. Commission on Engineering and Technical Systems. Washington, DC: National Academy Press; 1997a.

    Google Scholar 

  3. Williamsen JE. Orbital Debris Risk Analysis and Survivability Enhancement for Freedom Station Manned Modules. AIAA-92-1410. AIAA Space Programs and Technologies Conference March 24-27, 1992.

    Google Scholar 

  4. Kolesari GL, Kindwall EP. Survival following accidental decom-pression to an altitude greater than 74,000 feet (22,555 m). Aviat Space Environ Med 1982; 53:1211-1214.

    PubMed  CAS  Google Scholar 

  5. Boyle III., J., Theoretical trans-respiratory pressure during rapid decompression: I. Model experiments and II. Animal experi-ments. Aerosp Med 1973; 44:153-162.

    Google Scholar 

  6. Malhotra MS, Wright HC. The effect of raised intrapulmonary pressure on the lungs of fresh unchilled bound and unbound cadavers. Med Res Council (RN PRC) Report 1960; UPS 189.

    Google Scholar 

  7. Carpenter CR. Recurrent pulmonary barotrauma in scuba div-ing and the risks of future hyperbaric exposures: A case report. Undersea Hyperb Med 1997; 4:209-213.

    Google Scholar 

  8. Dulchavsky SA, Hamilton DR, Diebel LN, Sargsyan AE, Billica RD, Williams DR. Thoracic ultrasound diagnosis of pneumotho-rax. J Trauma. 1999; 47:970-971.

    Article  PubMed  CAS  Google Scholar 

  9. Parris C, Frenkiel S. Effects and management of barometric change on cavities in the head and neck. J Otolaryngol, 1995; 24:46-50.

    PubMed  CAS  Google Scholar 

  10. Teed RW. Factors producing obstruction of the auditory tube in submarine personnel. US Navy Med Bull 1944; 44:293-306.

    Google Scholar 

  11. Ashton DH, Watson LA. The use of tympanometry in predicting otic barotrauma. Aviat Space Environ Med 1990; 61:56-61.

    PubMed  CAS  Google Scholar 

  12. Paaske PB, Staunstrup HN, Malling B, Knudsen L. Imped-ance measurement in divers during a scuba-diving training pro-gramme. Clin Otolaryngol 1991; 16:145-148.

    Article  PubMed  CAS  Google Scholar 

  13. Strutz J. Otorhinolaryngologic aspects of diving sports. HNO 1993; 41:401-411.

    PubMed  CAS  Google Scholar 

  14. Molvaer OI. Vestibular problems in diving and in space. Scand Audiol Suppl 1991; 34:163-170.

    PubMed  CAS  Google Scholar 

  15. Lundgren CEG. Alternobaric vertigo—a diving hazard. BMJ 1965; 2:511.

    Article  PubMed  CAS  Google Scholar 

  16. Lundgren CEG, Malm LU. Alternobaric vertigo among pilots. Aerosp Med 1966; 37:178.

    PubMed  CAS  Google Scholar 

  17. Singleton GT. Diagnosis and treatment of perilymph fistu-las without hearing loss. Otolaryngol Head Neck Surg 1986; 94:426-429.

    PubMed  CAS  Google Scholar 

  18. Nakashima T, Kaida M, Yanagita N. Round window membrane rupture and inner ear damage due to barotrauma. Acta Otolaryn-gol Suppl (Stockh) 1992; 493:57-62.

    CAS  Google Scholar 

  19. Antonelli PJ, Parell GJ, Becker GD, Paparella MM. Temporal bone pathology in scuba diving deaths. Otolaryngol Head Neck Surg 1993; 109:514-521.

    PubMed  CAS  Google Scholar 

  20. Kamerer DB, Sando I, Hirsch B, Takagi A. Perilymph fistula resulting from microfissures. Am J Otol 1987; 8:489-494.

    PubMed  CAS  Google Scholar 

  21. Ashton DH, Watson LA. Inner ear barotrauma: A case for explor-atory tympanotomy. Aviat Space Environ Med 1992; 63:612-615.

    PubMed  CAS  Google Scholar 

  22. Black FO, Pesznecker S, Norton T, et al. Surgical management of perilymphatic fistulas: A Portland experience. Am J Otol 1992; 13:254-262.

    PubMed  CAS  Google Scholar 

  23. Seltzer S, McCabe BF. Perilymph fistula: The Iowa experience. Laryngoscope 1986; 96:37-49.

    Article  PubMed  CAS  Google Scholar 

  24. Adkisson GH, Meredith AP. Inner ear decompression sickness combined with a fistula of the round window. Case report. Ann Otol Rhinol Laryngol 1990; 99:733-737.

    PubMed  CAS  Google Scholar 

  25. Shupak A, Doweck I, Greenberg E, Gordon CR, Spitzer O, Melamed Y, Meyer WS. Diving-related inner ear injuries. Laryn-goscope 1991; 101:173-179.

    CAS  Google Scholar 

  26. Reissman P, Shupak A, Nachum Z, Melamed Y. Inner ear decom-pression sickness following a shallow scuba dive. Aviat Space Environ Med 1990; 61:563-566.

    PubMed  CAS  Google Scholar 

  27. Talmi YP, Finkelstein Y, Zohar Y. Barotrauma-induced hearing loss. Scand Audiol 1991; 20:1-9.

    PubMed  CAS  Google Scholar 

  28. Talmi YP, Finkelstein Y, Zohar Y. Decompression sickness induced hearing loss. A review. Scand Audiol 1991; 20:25-28.

    PubMed  CAS  Google Scholar 

  29. Shupak A. Inner ear decompression sickness combined with a fistula of the round window (letter). Ann Otol Rhinol Laryngol 1991; 100:788.

    PubMed  CAS  Google Scholar 

  30. Stangerup S-E, Tjernstrom Ă–, Klokker M, Harcourt J, and Stokholm J. Point prevalence of barotitis in children and adults after flight, and effect of autoinflation. Aviat Space Environ Med 1998; 69:45-49.

    PubMed  CAS  Google Scholar 

  31. Parell GJ, Becker GD. Inner ear barotrauma in scuba divers. A long-term follow-up after continued diving. Arch Otolaryngol Head Neck Surg 1993; 119:455-457.

    PubMed  CAS  Google Scholar 

  32. Davenport NA. Predictors of barotrauma events in the Navy alti-tude chamber. Aviat Space Environ Med 1997; 68:61-65.

    PubMed  CAS  Google Scholar 

  33. Meehan RT, Zavala DC. The pathophysiology of acute high-alti-tude illness. Am J Med 1982; 73:395-403.

    Article  PubMed  CAS  Google Scholar 

  34. Bärtsch P. High altitude pulmonary edema. Med Sci Sports Exerc 1999; 31(1 Suppl.):S23-S27.

    PubMed  Google Scholar 

  35. Hackett PH. High altitude cerebral edema and acute mountain sick-ness: A pathophysiology update. Adv Exp Med Biol 1999; 474:23.

    PubMed  CAS  Google Scholar 

  36. Hultgren HN. High-altitude pulmonary edema: Current concepts. Annu Rev Med 1996; 47:267.

    Article  PubMed  CAS  Google Scholar 

  37. Sutton JR. Mountain sickness. Neurol Clin 1992; 10:1015-1030.

    PubMed  CAS  Google Scholar 

  38. Tso E. High-altitude illness. Emerg Med Clin North Am 1992; 10:231-247.

    PubMed  CAS  Google Scholar 

  39. Ward MP, Milledge JS, West JB. High Altitude Medicine and Physiology. London: Chapman and Hall Medical; 1995.

    Google Scholar 

  40. Hackett PH. The cerebral etiology of high-altitude cerebral edema and acute mountain sickness. Wilderness Environ Med 1999; 10:97-109.

    PubMed  CAS  Google Scholar 

  41. Foutch RG, Henrichs W. Carbon monoxide poisoning at high altitudes. Am J Emerg Med 1988; 6:596-598.

    Article  PubMed  CAS  Google Scholar 

  42. Sampson JB, Cymerman A, Burse RL, Maher JT, Rock PB. Pro-cedures for the measurement of acute mountain sickness. Aviat Space Environ Med 1983; 54:1063-1073.

    PubMed  CAS  Google Scholar 

  43. Roeggla G, Roeggla M, Podolsky A, Wagner A, Laggner AN. How can acute mountain sickness be quantified at moderate alti-tude? J R Soc Med 1996; 89:141-143.

    PubMed  CAS  Google Scholar 

  44. Savourey G, Guinet A, Besnard Y, Garcia N, Hanniquet AM, Bittel J. Evaluation of the Lake Louise acute mountain sickness scoring system in a hypobaric chamber. Aviat Space Environ Med 1995; 66:963-967.

    PubMed  CAS  Google Scholar 

  45. Maggiorini M, Muller A, Hofstetter D, Bärtsch P, Oelz O. Assess-ment of acute mountain sickness by different score protocols in the Swiss Alps. Aviat Space Environ Med 1998; 69:1186-1192.

    PubMed  CAS  Google Scholar 

  46. Savourey G, Guinet A, Besnard Y, Garcia N, Hanniquet A-M, Bittel J. Are the laboratory and field conditions observations of acute mountain sickness related? Aviat Space Environ Med 1997; 68:895-899.

    PubMed  CAS  Google Scholar 

  47. Swenson ER, MacDonald A, Vatheuer MI, Maks C, Treadwell A, Allen R, Schoene RB. Acute mountain sickness is not altered by a high carbohydrate diet nor associated with elevated circulat-ing cytokines. Aviat Space Environ Med 1997; 68:499-503.

    PubMed  CAS  Google Scholar 

  48. Purkayastha SS, Ray US, Arora BS, Chhabra PC, Thakur L, Ban-dopadhyay P, Selvamurthy W. Acclimatization at high altitude in gradual and acute induction. J Appl Physiol 1995; 79:487-492.

    PubMed  CAS  Google Scholar 

  49. Honigman B, Read M, Lezotte D, Roach RC. Sea-level physical activity and acute mountain sickness at moderate altitude. West J Med 1995; 163:117-121.

    PubMed  CAS  Google Scholar 

  50. Goldenberg F, Richalet JP, Onnen I, Antezana AM. Sleep apneas and high altitude newcomers. Int J Sports Med 1992; 13: S34-S36.

    Article  PubMed  Google Scholar 

  51. Lyons TP, Muza SR, Rock PB, Cymerman A. The effect of alti-tude pre-acclimatization on acute mountain sickness during reex-posure. Aviat Space Environ Med 1995; 66:957-962.

    PubMed  CAS  Google Scholar 

  52. Rathat C, Richalet JP, Herry JP, Larmignat P. Detection of high-risk subjects for high altitude diseases. Int J Sports Med 1992; 13:S76-S78.

    Article  PubMed  Google Scholar 

  53. Roach RC, Greene ER, Schoene RB, Hackett PH. Arterial oxy-gen saturation for prediction of acute mountain sickness. Aviat Space Environ Med 1998; 69:1182-1185.

    PubMed  CAS  Google Scholar 

  54. Hohenhaus E, Paul A, McCullough RE, Kucherer H, Bärtsch P. Ventilatory and pulmonary vascular response to hypoxia and sus-ceptibility to high altitude pulmonary edema. Eur Respir J 1995; 8:1825-1833.

    Article  PubMed  CAS  Google Scholar 

  55. Bärtsch P. Who gets altitude sickness? Schweiz Med Wochenschr 1992; 122:307-314.

    PubMed  Google Scholar 

  56. Milledge JS, Beeley JM, Broome J, Luff N, Pelling M, Smith D. Acute mountain sickness susceptibility, fitness and hypoxic ventilatory response. Eur Respir J 1991; 4:1000-1003.

    PubMed  CAS  Google Scholar 

  57. Richalet JP, Keromes A, Carillion A, Mehdioui H, Larmignat P, Rathat C. Cardiac response to hypoxia and susceptibility to mountain sickness. Arch Mal Coeur Vaiss 1989; 82:49-54.

    PubMed  Google Scholar 

  58. Loeppky JA, Roach RC, Selland MA, Scotto P, Luft FC, Luft UC. Body fluid alterations during head-down bed rest in men at moderate altitude. Aviat Space Environ Med 1993; 64:265-274.

    PubMed  CAS  Google Scholar 

  59. Loeppky JA, Roach RC, Selland MA, Scotto P, Greene ER, Luft UC. Effects of prolonged head-down bed rest on physiological responses to moderate hypoxia. Aviat Space Environ Med 1993; 64:275-286

    PubMed  CAS  Google Scholar 

  60. Westerterp KR, Robach P, Wouters L, Richalet JP. Water bal-ance and acute mountain sickness before and after arrival at high altitude of 4,350 m. J Appl Physiol 1996; 80:1968-1972.

    PubMed  CAS  Google Scholar 

  61. Tucker A, Reeves JT, Robertshaw D, Grover RF. Cardiopul-monary response to acute altitude exposure: Water loading and denitrogenation. Respir Physiol 1983; 54:363-380.

    CAS  Google Scholar 

  62. Roach RC, Loeppky JA, Icenogle MV. Acute mountain sickness: Increased severity during simulated altitude compared with normobaric hypoxia. J Appl Physiol 1996; 81:1908-1910.

    PubMed  CAS  Google Scholar 

  63. Saldias F, Beroiza T, Lisboa C. Acute altitude sickness and ven-tilatory function in subjects intermittently exposed to hypobaric hypoxia. Rev Med Chil 1995; 123:44-50.

    PubMed  CAS  Google Scholar 

  64. Richalet JP, Rutgers V, Bouchet P, Rymer JC, Keromes A, Duval-Arnould G, Rathat C. Diurnal variations of acute mountain sick-ness, color vision, and plasma cortisol and ACTH at high altitude. Aviat Space Environ Med 1989; 60:105-111.

    PubMed  CAS  Google Scholar 

  65. Otis SM, Rossman ME, Schneider PA, Rush MP, Ringelstein EB. Relationship of cerebral blood flow regulation to acute mountain sickness. J Ultrasound Med 1989; 8:143-148.

    PubMed  CAS  Google Scholar 

  66. Buck A, Schirlo C, Jasinksy V, et al. Changes of cerebral blood flow during short-term exposure to normobaric hypoxia. J Cereb Blood Flow Metab 1998; 18:906-910.

    Article  PubMed  CAS  Google Scholar 

  67. Baumgartner RW, Bärtsch P, Maggiorini M, Waber U, Oelz O. Enhanced cerebral blood flow in acute mountain sickness. Aviat Space Environ Med 1994; 65:726-729.

    PubMed  CAS  Google Scholar 

  68. Wright AD, Imray CH, Morrissey MS, Marchbanks RJ, Bradwell AR. Intracranial pressure at high altitude and acute mountain sickness. Clin Sci (Colch) 1995; 89:201-204.

    CAS  Google Scholar 

  69. Grissom CK, Zimmerman GA, Whatley RE. Endothelial selec-tins in acute mountain sickness and high-altitude pulmonary edema. Chest 1997; 112:1572-1578.

    Article  PubMed  CAS  Google Scholar 

  70. Klausen T, Olsen NV, Poulsen TD, Richalet JP, Pedersen BK. Hypoxemia increases serum interleukin-6 in humans. Eur J Appl Physiol 1997; 76:480-482.

    Article  CAS  Google Scholar 

  71. Larsen JJ, Hansen JM, Olsen NV, Galbo H, Dela F. The effect of altitude hypoxia on glucose homeostasis in men. J Physiol (London) 1997; 504:241-249.

    Article  CAS  Google Scholar 

  72. Milledge JS, Beeley JM, McArthur S, Morice AH. Atrial natri-uretic peptide, altitude and acute mountain sickness. Clin Sci 1989; 77:509-514.

    PubMed  CAS  Google Scholar 

  73. Bouissou P, Richalet JP, Galen FX, et al. Effect of beta-adre-noceptor blockade on renin-aldosterone and alpha-ANF during exercise at altitude. J Appl Physiol 1989; 67:141-146.

    PubMed  CAS  Google Scholar 

  74. Bailey DM, Davies B. Physiological implications of altitude training for endurance performance at sea level: A review. Br J Sports Med 1997; 31:183-190.

    Article  CAS  Google Scholar 

  75. Clark I. Can excessive iNOS induction explain much of the illness of acute mountain sickness? In Roach R. Wagner P. Hackett P. (eds.), Hypoxia: Into the Next Millennium. New York, NY: Kluwer Academic/Plenum Press; 1999.

    Google Scholar 

  76. Murdoch DR. Symptoms of infection and altitude illness among hikers in the Mount Everest region of Nepal. Aviat Space Envi-ron Med 1995; 66:148-151.

    CAS  Google Scholar 

  77. Bailey DM, Davies B, Romer L, Castell L, Newsholme E, Gandy G. Implications of moderate altitude training for sea-level endurance in elite distance runners. Eur J Appl Physiol 1998; 78:360-368.

    Article  CAS  Google Scholar 

  78. Durmowicz AG, Noordeweir E, Nicholas R, Reeves JT. Inflam-matory processes may predispose children to high-altitude pul-monary edema. J Pediatr 1997; 130:838-840.

    Article  PubMed  CAS  Google Scholar 

  79. Naeije R. Pulmonary circulation at high altitude. Respiration 1997; 64:429-434.

    Article  PubMed  CAS  Google Scholar 

  80. Eichenberger U, Weiss E, Riemann D, Oelz O, Bärtsch P. Noc-turnal periodic breathing and the development of acute high alti-tude illness. Am J Respir Crit Care Med 1996; 154:1748-1754.

    PubMed  CAS  Google Scholar 

  81. Bärtsch P. High altitude pulmonary edema. Respiration 1997; 64:435-443.

    Article  PubMed  Google Scholar 

  82. Selland MA, Stelzner TJ, Stevens T, Mazzeo RS, McCullough RE, Reeves JT. Pulmonary function and hypoxic ventilatory response in subjects susceptible to high-altitude pulmonary edema. Chest 1993 Jan.; 103(1):111-116.

    Article  PubMed  CAS  Google Scholar 

  83. Schoene RB, Swenson ER, Pizzo CJ, Hackett PH, Roach RC, Mills WJ Jr, Henderson WR Jr, Martin TR. The lung at high altitude: Bronchoalveolar lavage in acute moun-tain sickness and pulmonary edema. J Appl Physiol 1988; 64:2605-2613.

    PubMed  CAS  Google Scholar 

  84. Kleger GR, Bärtsch P, Vock P, Heilig B, Roberts LJ 2nd, Ballmer PE. Evidence against an increase in capillary perme-ability in subjects exposed to high altitude. J Appl Physiol 1996; 81:1917-1923.

    PubMed  CAS  Google Scholar 

  85. Hamilton AJ, Cymmerman A, Black PM. High altitude cerebral edema. Neurosurgery 1986; 19:841-849.

    Article  PubMed  CAS  Google Scholar 

  86. Clarke C. High altitude cerebral oedema. Int J Sports Med 1988 Apr.; 9:170-174.

    Article  PubMed  CAS  Google Scholar 

  87. Krasney JA. A neurogenic basis for acute altitude illness. Med Sci Sports Exerc 1994; 26:195-208.

    Article  PubMed  CAS  Google Scholar 

  88. Houston CS, Dickinson J. Cerebral form of high-altitude illness. Lancet 1975 Oct. 18; 2(7938):758-761.

    CAS  Google Scholar 

  89. Grissom CK, Roach RC, Sarnquist FH, Hackett PH. Acet-azolamide in the treatment of acute mountain sickness: Clini-cal efficacy and effect on gas exchange. Ann Intern Med 1992; 116:461-465.

    PubMed  CAS  Google Scholar 

  90. Bradwell AR, Wright AD, Winterborn M, Imray C. Acetazol-amide and high altitude diseases. Int J Sports Med 1992; 13: S63-S64.

    Article  PubMed  Google Scholar 

  91. Ritschel WA, Paulos C, Arancibia A, Agrawal MA, Wetzels-berger KM, Lucker PW. Pharmacokinetics of acetazolamide in healthy volunteers after short- and long-term exposure to high altitude. J Clin Pharmacol 1998; 38:533-539.

    PubMed  CAS  Google Scholar 

  92. Bernhard WN, Schalick LM, Delaney PA, Bernhard TM, Barnas GM. Acetazolamide plus low-dose dexamethasone is better than acetazolamide alone to ameliorate symptoms of acute mountain sickness. Aviat Space Environ Med 1998; 69:883-886.

    PubMed  CAS  Google Scholar 

  93. Coote JH. Medicine and mechanisms in altitude sickness. Rec-ommendations. Sports Med 1995; 20:148-159.

    Article  PubMed  CAS  Google Scholar 

  94. Hackett PH, Roach RC. Medical therapy of altitude illness. Ann Emerg Med 1987; 16:980-986.

    Article  PubMed  CAS  Google Scholar 

  95. Porcelli MJ, Gugelchuk GM. A trek to the top: A review of acute mountain sickness. J Am Osteopath Assoc 1995; 95:718-720.

    PubMed  CAS  Google Scholar 

  96. Levine BD, Yoshimura K, Kobayashi T, Fukushima M, Shibamoto T, Ueda G. Dexamethasone in the treatment of acute mountain sickness. N Engl J Med 1989; 321:1707-1713.

    Article  PubMed  CAS  Google Scholar 

  97. Hackett PH, Roach RC, Wood RA, Foutch RG, Meehan RT, Rennie D, Mills WJ Jr. Dexamethasone for prevention and treat-ment of acute mountain sickness. Aviat Space Environ Med 1988; 59:950-954.

    PubMed  CAS  Google Scholar 

  98. Ellsworth AJ, Larson EB, Strickland D. A randomized trial of dexamethasone and acetazolamide for acute mountain sickness prophylaxis. Am J Med 1987; 83:1024-1030.

    Article  PubMed  CAS  Google Scholar 

  99. Hohenhaus E, Niroomand F, Goerre S, Vock P, Oelz O, Bärtsch P. Nifedipine does not prevent acute mountain sickness. Am J Respir Crit Care Med 1994; 150:857-860.

    PubMed  CAS  Google Scholar 

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Clark, J.B. (2008). Decompression-Related Disorders: Pressurization Systems, Barotrauma, and Altitude Sickness. In: Barratt, M.R., Pool, S.L. (eds) Principles of Clinical Medicine for Space Flight. Springer, New York, NY. https://doi.org/10.1007/978-0-387-68164-1_12

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