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Working in permanent hypoxia for fire protection—impact on health

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Abstract

Objectives

A new technique to prevent fires is continuous exchange of oxygen with nitrogen which leads to an oxygen concentration of between 15% and 13% in the ambient air. This paper reviews the effect of short-term, intermittent hypoxia on health and performance of people working in such atmospheres.

Methods

We reviewed the effect of ambient air hypoxia on human health in the literature using Medline, as well as reference lists of articles and handbooks. Articles were assessed from the perspective of working conditions in fire-protected rooms.

Results

Oxygen reduced to 15% and 13% in normobaric atmospheres is equivalent to the hypobaric atmospheres found at 2,700 and 3,850-m altitudes. When acutely exposed, a healthy person responds within minutes to hours with increased ventilation, stimulation of the sympathetic system, increased heart rate, increased pulmonary-circulation resistance, reduced plasma volume, and stimulation of erythropoesis. Acute mountain sickness occurs frequently at these oxygen partial pressures, but the full syndrome is rare if continuous exposure is limited to 6 h. Mood, cognitive, and psychomotor functions may be mildly impaired in these conditions, but data are inconclusive. Persons suffering from cardiac, pulmonary, or hematological diseases should consult a specialist in order for their individual risk to be assessed, and medical screening for any of these diseases is strongly recommended prior to exposure.

Conclusion

Preliminary evidence suggests that working environments with low oxygen concentrations to a minimum of 13% and normal barometric pressure do not impose a health hazard, provided that precautions are observed, comprising medical examinations and limitation of exposure time. However, evidence is limited, particularly with regard to workers performing strenuous tasks or having various diseases. Therefore, close monitoring of the health problems of people working in low oxygen atmospheres is necessary.

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References

  1. Abraini JH, Bouquet C, Joulia F, et al. (1998) Cognitive performance during a simulated climb of Mount Everest: implications for brain function and central adaptive processes under chronic hypoxic stress. Pflugers Arch 436:553–559

    Article  CAS  PubMed  Google Scholar 

  2. Agostoni P, Cattadori G, Guazzi M, et al. (2000) Effects of simulated altitude-induced hypoxia on exercise capacity in patients with chronic heart failure. Am J Med 109:450–455

    Article  CAS  PubMed  Google Scholar 

  3. American Thoracic Society (1995) Standards for the diagnosis and care of patients with chronic obstructive pulmonary disease. Am J Respir Crit Care Med 152:S77–121

    PubMed  Google Scholar 

  4. Anooshiravani M, Dumont L, Mardirosoff C, et al. (1999) Brain magnetic resonance imaging (MRI) and neurological changes after a single high altitude climb. Med Sci Sports Exerc 31:969–972

    CAS  PubMed  Google Scholar 

  5. Banderet LE (1977) Self-rated moods of humans at 4300 m pretreated with placebo or acetazolamide plus staging. Aviat Space Environ Med 48:19–22

    CAS  PubMed  Google Scholar 

  6. Barry M, Bia F (1989) Pregnancy and travel. JAMA 261:728–731

    CAS  PubMed  Google Scholar 

  7. Bartholomew CJ, Jensen W, Petros TV, et al. (1999) The effect of moderate levels of simulated altitude on sustained cognitive performance. Int J Aviat Psychol 9:351–359

    CAS  PubMed  Google Scholar 

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

    CAS  PubMed  Google Scholar 

  9. Burtscher M, Philadelphy M, Likar R (1993) Sudden cardiac death during mountain hiking and downhill skiing. N Engl J Med 329:1738–1739

    Article  CAS  Google Scholar 

  10. Burtscher M, Likar R, Nachbauer W, et al. (1998) Aspirin for prophylaxis against headache at high altitudes: randomised, double blind, placebo controlled trial. BMJ 316:1057–1058

    CAS  PubMed  Google Scholar 

  11. Cote TR, Stroup DF, Dwyer DM, et al. (1993) Chronic obstructive pulmonary disease mortality. A role for altitude. Chest 103:1194–1197

    CAS  PubMed  Google Scholar 

  12. Cottrell JJ (1988) Altitude exposures during aircraft flight. Flying higher. Chest 93:81–84

    CAS  PubMed  Google Scholar 

  13. Crow TJ, Kelman GG (1969) Psychological effects of mild hypoxia. J Physiol 204:24

    Google Scholar 

  14. Crow TJ, Kelman GR (1971) Effect of mild acute hypoxia on human short-term memory. Br J Anaesth 43:548–552

    CAS  PubMed  Google Scholar 

  15. Crowley JS, Wesensten N, Kamimori G, et al. (1992) Effect of high terrestrial altitude and supplemental oxygen on human performance and mood. Aviat Space Environ Med 63:696–701

    CAS  PubMed  Google Scholar 

  16. Dean AG, Yip R, Hoffmann RE (1990) High incidence of mild acute mountain sickness in conference attendees at 10,000 foot altitude. J Wilderness Med 1:86–92

    Google Scholar 

  17. Denison DM, Ledwith F, Poulton EC (1966) Complex reaction times at simulated cabin altitudes of 5,000 feet and 8,000 feet. Aerosp Med 37:1010–1013

    CAS  PubMed  Google Scholar 

  18. Dillard TA, Moores LK, Bilello KL, et al. (1995) The preflight evaluation. A comparison of the hypoxia inhalation test with hypobaric exposure. Chest 107:352–357

    CAS  PubMed  Google Scholar 

  19. Dillard TA, Rajagopal KR, Slivka WA, et al. (1998) Lung function during moderate hypobaric hypoxia in normal subjects and patients with chronic obstructive pulmonary disease. Aviat Space Environ Med 69:979–985

    CAS  PubMed  Google Scholar 

  20. Erdmann J, Sun KT, Masar P, et al. (1998) Effects of exposure to altitude on men with coronary artery disease and impaired left ventricular function. Am J Cardiol 81:266–270

    Article  CAS  PubMed  Google Scholar 

  21. Ernsting J (1978) Prevention of hypoxia—acceptable compromises. Aviat Space Environ Med 49:495–502

    CAS  PubMed  Google Scholar 

  22. Forster P (1984) Reproducibility of individual response to exposure to high altitude. BMJ 289:1269

    CAS  Google Scholar 

  23. Forster PJ (1985) Effect of different ascent profiles on performance at 4,200 m elevation. Aviat Space Environ Med 56:758–764

    CAS  PubMed  Google Scholar 

  24. Forster PJG (2000) Working at high altitude. In: Baxter PJ, Adams PH, Aw T-C, Cockroft A, Harrington M (eds) Hunter's disease of occupations, 9th edn. Arnold, London, pp 383–396

  25. Forwand SA, Landowne M, Follansbee JN, et al. (1968) Effect of acetazolamide on acute mountain sickness. N Engl J Med 279:839–845

    CAS  PubMed  Google Scholar 

  26. Fowler B, Paul M, Porlier G, et al. (1985) A re-evaluation of the minimum altitude at which hypoxic performance decrements can be detected. Ergonomics 28:781–791

    CAS  PubMed  Google Scholar 

  27. Fowler B, Taylor M, Porlier G (1987) The effects of hypoxia on reaction time and movement time components of a perceptual-motor task. Ergonomics 30:1475–1485

    CAS  PubMed  Google Scholar 

  28. Fraser WD, Eastman DE, Paul MA, et al. (1987) Decrement in postural control during mild hypobaric hypoxia. Aviat Space Environ Med 58:768–772

    CAS  PubMed  Google Scholar 

  29. Garrido E, Castello A, Ventura JL, et al. (1993) Cortical atrophy and other brain magnetic resonance imaging (MRI) changes after extremely high-altitude climbs without oxygen. Int J Sports Med 14:232–234

    CAS  PubMed  Google Scholar 

  30. Garrido E, Segura R, Capdevila A, et al. (1995) New evidence from magnetic resonance imaging of brain changes after climbs at extreme altitude. Eur J Appl Physiol Occup Physiol 70:477–481

    CAS  PubMed  Google Scholar 

  31. Gong H, Tashkin DP, Lee EY, et al. (1984) Hypoxia-altitude simulation test. Evaluation of patients with chronic airway obstruction. Am Rev Respir Dis 130:980–986

    PubMed  Google Scholar 

  32. Graham WG, Houston CS (1978) Short-term adaptation to moderate altitude. Patients with chronic obstructive pulmonary disease. JAMA 240:1491–1494

    CAS  PubMed  Google Scholar 

  33. Green RG, Morgan DR (1985) The effects of mild hypoxia on a logical reasoning task. Aviat Space Environ Med 56:1004–1008

    PubMed  Google Scholar 

  34. Grover RF, Lufschanowski R, Alexander JK (1976) Alterations in the coronary circulation of man following ascent to 3,100 m altitude. J Appl Physiol 41:832–838

    CAS  PubMed  Google Scholar 

  35. Gustafsson C, Gennser M, Ornhagen H, et al. (1997) Effects of normobaric hypoxic confinement on visual and motor performance. Aviat Space Environ Med 68:985–992

    CAS  PubMed  Google Scholar 

  36. Habler OP, Messmer KF (1997) The physiology of oxygen transport. Transfus Sci 18:425–435

    Article  CAS  PubMed  Google Scholar 

  37. Hackett PH, Rennie D (1976) The incidence, importance, and prophylaxis of acute mountain sickness. Lancet 2:1149–1155

    CAS  PubMed  Google Scholar 

  38. Hackett PH, Roach RC (2001) High-altitude illness. N Engl J Med 345:107–114

    Article  CAS  PubMed  Google Scholar 

  39. Hammond MD, Gale GE, Kapitan KS, et al. (1986) Pulmonary gas exchange in humans during normobaric hypoxic exercise. J Appl Physiol 61:1749–1757

    CAS  PubMed  Google Scholar 

  40. Harinck E, Hutter PA, Hoorntje TM, et al. (1996) Air travel and adults with cyanotic congenital heart disease. Circulation 93:272–276

    CAS  PubMed  Google Scholar 

  41. Holness DE, Fraser WD, Eastman DE, et al. (1982) Postural stability during slow-onset and rapid-onset hypoxia. Aviat Space Environ Med 53:647–651

    CAS  PubMed  Google Scholar 

  42. Honigman B, Theis MK, Koziol-McLain J, et al. (1993) Acute mountain sickness in a general tourist population at moderate altitudes. Ann Intern Med 118:587–592

    CAS  PubMed  Google Scholar 

  43. Hornbein TF, Townes BD, Schoene RB, et al. (1989) The cost to the central nervous system of climbing to extremely high altitude. N Engl J Med 321:1714–1719

    CAS  PubMed  Google Scholar 

  44. Hultgren HN, Marticorena EA (1978) High altitude pulmonary edema. Epidemiologic observations in Peru. Chest 74:372–376

    CAS  PubMed  Google Scholar 

  45. Jobe JB, Shukitt-Hale B, Banderet LE, et al. (1991) Effects of dexamethasone and high terrestrial altitude on cognitive performance and affect. Aviat Space Environ Med 62:727–732

    CAS  PubMed  Google Scholar 

  46. Kaijser L, Grubbstrom J, Berglund B (1990) Coronary circulation in acute hypoxia. Clin Physiol 10:259–263

    CAS  PubMed  Google Scholar 

  47. Kennedy RS, Dunlap WP, Banderet LE, et al. (1989) Cognitive performance deficits in a simulated climb of Mount Everest: Operation Everest II. Aviat Space Environ Med 60:99–104

    CAS  PubMed  Google Scholar 

  48. Kleinman MT, Leaf DA, Kelly E, et al. (1998) Urban angina in the mountains: effects of carbon monoxide and mild hypoxemia on subjects with chronic stable angina. Arch Environ Health 53:388–397

    CAS  PubMed  Google Scholar 

  49. Knight DR, Cymerman A, Devine JA, et al. (1990) Symptomatology during hypoxic exposure to flame-retardant chamber atmospheres. Undersea Biomed Res 17:33–44

    CAS  PubMed  Google Scholar 

  50. Knight DR, Schlichting CL, Fulco CS, et al. (1990) Mental performance during submaximal exercise in 13 and 17% oxygen. Undersea Biomed Res 17:223–230

    CAS  PubMed  Google Scholar 

  51. Koller EA, Bischoff M, Buhrer A, et al. (1991) Respiratory, circulatory and neuropsychological responses to acute hypoxia in acclimatized and non-acclimatized subjects. Eur J Appl Physiol Occup Physiol 62:67–72

    CAS  PubMed  Google Scholar 

  52. Kopp P, Negri M, Wegmuller E, et al. (1989) 2 cases of acute sickle cell crisis in subjects with sickle cell trait following high altitude exposure. Schweiz Med Wochenschr 119:1358–1359

    CAS  PubMed  Google Scholar 

  53. Kraus WE (2000) Taking heart failure to new heights: its pathophysiology at simulated altitude. Am J Med 109:504–505

    Article  CAS  PubMed  Google Scholar 

  54. Leifflen D, Poquin D, Savourey G, et al. (1997) Cognitive performance during short acclimation to severe hypoxia. Aviat Space Environ Med 68:993–997

    CAS  PubMed  Google Scholar 

  55. Levine BD, Zuckerman JH, deFilippi CR (1997) Effect of high-altitude exposure in the elderly: the Tenth Mountain Division study. Circulation 96:1224–1232

    CAS  PubMed  Google Scholar 

  56. Mann DL (1999) Mechanisms and models in heart failure: a combinatorial approach. Circulation 100:999–1008

    PubMed  Google Scholar 

  57. Matthys H, Volz H, Ernst H, et al. (1974) Kardiopulmonale Belastung von Flugpassagieren mit obstruktiven Ventilationsstorungen. Schweiz Med Wochenschr 104:1786–1789

    CAS  PubMed  Google Scholar 

  58. McCarthy D, Corban R, Legg S, et al. (1995) Effects of mild hypoxia on perceptual-motor performance: a signal-detection approach. Ergonomics 38:1979–1992

    CAS  PubMed  Google Scholar 

  59. Montgomery AB, Mills J, Luce JM (1989) Incidence of acute mountain sickness at intermediate altitude. JAMA 261:732–734

    CAS  PubMed  Google Scholar 

  60. Morgan BJ, Alexander JK, Nicoli SA, et al. (1990) The patient with coronary heart disease at altitude: observations during acute exposure to 3100 m. J Wilderness Med 1:147–153

    Google Scholar 

  61. Naughton MT, Rochford PD, Pretto JJ, et al. (1995) Is normobaric simulation of hypobaric hypoxia accurate in chronic airflow limitation? Am J Respir Crit Care Med 152:1956–1960

    CAS  PubMed  Google Scholar 

  62. Niermeyer S (1999) The pregnant altitude visitor. Adv Exp Med Biol 474:65–77

    CAS  PubMed  Google Scholar 

  63. Nishihara F, Shimada H, Saito S (1998) Rate pressure product and oxygen saturation in tourists at approximately 3000 m above sea level. Int Arch Occup Environ Health 71:520–524

    Article  CAS  PubMed  Google Scholar 

  64. Nordahl SH, Aasen T, Owe JO, et al. (1998) Effects of hypobaric hypoxia on postural control. Aviat Space Environ Med 69:979–985

    CAS  PubMed  Google Scholar 

  65. Paul MA, Fraser WD (1994) Performance during mild acute hypoxia. Aviat Space Environ Med 65:891–899

    CAS  PubMed  Google Scholar 

  66. Piehl Aulin K, Svedenhag J, Wide L, et al. (1998) Short-term intermittent normobaric hypoxia--haematological, physiological and mental effects. Scand J Med Sci Sports 8:132–137

    PubMed  Google Scholar 

  67. Regard M, Landis T, Casey J, et al. (1991) Cognitive changes at high altitude in healthy climbers and in climbers developing acute mountain sickness. Aviat Space Environ Med 62:291–295

    CAS  PubMed  Google Scholar 

  68. Roach PC, Bärtsch P, Oelz O, et al. (1993) The Lake Louise acute mountain sickness scoring system. In: Sutton JR, Houston CS, Coates G (eds) Hypoxia and molecular medicine. Houston, Burlington, Vt pp 272–274

  69. Roach RC, Houston CS, Honigman B, et al. (1995) How well do older persons tolerate moderate altitude? West J Med 162:32–36

    CAS  PubMed  Google Scholar 

  70. Roach RC, Loeppky JA, Icenogle MV (1996) Acute mountain sickness: increased severity during simulated altitude compared with normobaric hypoxia. J Appl Physiol 81:1908–1910

    CAS  PubMed  Google Scholar 

  71. Roach RC, Maes D, Sandoval D, et al. (2000) Exercise exacerbates acute mountain sickness at simulated high altitude. J Appl Physiol 88:581–585

    CAS  PubMed  Google Scholar 

  72. Rose DM, Fleck B, Thews O, et al. (2000) Blood gas-analyses in patients with cystic fibrosis to estimate hypoxemia during exposure to high altitudes in a hypobaric-chamber. Aviat Space Environ Med 71:125–130

    CAS  PubMed  Google Scholar 

  73. Ryan TJ, Antman EM, Brooks NH, et al. (1999) 1999 update: ACC/AHA guidelines for the management of patients with acute myocardial infarction. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Management of Acute Myocardial Infarction). J Am Coll Cardiol 34:890–911

    CAS  PubMed  Google Scholar 

  74. Sausen KP, Wallick MT, Slobodnik B, et al. (2001) The reduced oxygen breathing paradigm for hypoxia training: physiological, cognitive, and subjective effects. Aviat Space Environ Med 72:539–545

    CAS  PubMed  Google Scholar 

  75. Savourey G, Guinet A, Besnard Y, et al. (1997) Are the laboratory and field conditions observations of acute mountain sickness related? Aviat Space Environ Med 68:895–899

    CAS  PubMed  Google Scholar 

  76. Schoene RB (1999) The brain at high altitude. Wilderness Environ Med 10:93–96

    CAS  PubMed  Google Scholar 

  77. Schoene RB (2001) Limits of human lung function at high altitude. J Exp Biol 204:3121–3127

    CAS  PubMed  Google Scholar 

  78. Schrier RW, Abraham WT (1999) Hormones and hemodynamics in heart failure. N Engl J Med 341:577–585

    Article  CAS  PubMed  Google Scholar 

  79. Schwartz JS, Bencowitz HZ, Moser KM (1984) Air travel hypoxemia with chronic obstructive pulmonary disease. Ann Intern Med 100:473–477

    CAS  PubMed  Google Scholar 

  80. Shlim DR, Houston R (1989) Helicopter rescues and deaths among trekkers in Nepal. JAMA 261:1017–1019

    CAS  PubMed  Google Scholar 

  81. Shukitt BL, Banderet LE (1988) Mood states at 1600 and 4300 meters terrestrial altitude. Aviat Space Environ Med 59:530–532

    CAS  PubMed  Google Scholar 

  82. Shukitt-Hale B, Banderet LE, Lieberman HR (1998) Elevation-dependent symptom, mood, and performance changes produced by exposure to hypobaric hypoxia. Int J Aviat Psychol 8:319–334

    CAS  PubMed  Google Scholar 

  83. Siafakas NM, Vermeire P, Pride NB, et al. (1995) Optimal assessment and management of chronic obstructive pulmonary disease (COPD). The European Respiratory Society Task Force. Eur Respir J 8:1398–1420

    CAS  PubMed  Google Scholar 

  84. Silber E (2000) Upper limb motor function at 5000 metres: determinants of performance and residual sequelae. J Neurol Neurosurg Psychiatry 69:233–236

    Article  CAS  PubMed  Google Scholar 

  85. Stivalet P, Leifflen D, Poquin D, et al. (2000) Positive expiratory pressure as a method for preventing the impairment of attentional processes by hypoxia. Ergonomics 43:474–485

    Article  CAS  PubMed  Google Scholar 

  86. Tiernan CJ (1999) Splenic crisis at high altitude in 2 white men with sickle cell trait. Ann Emerg Med 33:230–233

    CAS  PubMed  Google Scholar 

  87. Vaernes RJ, Owe JO, Myking O (1984) Central nervous reactions to a 6.5-hour altitude exposure at 3048 meters. Aviat Space Environ Med 55:921–926

    CAS  PubMed  Google Scholar 

  88. Ward PW, Milledge JS , West JB (2000) High altitude medicine and physiology. Arnold, London

  89. Weilenmann D, Duru F, Schonbeck M, et al. (2000) Influence of acute exposure to high altitude and hypoxemia on ventricular stimulation thresholds in pacemaker patients. Pacing Clin Electrophysiol 23:512–515

    CAS  PubMed  Google Scholar 

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Acknowledgements

This work was partly supported by an unrestricted grant provided by Wagner Alarm- und Sicherheitssysteme GmbH, Langenhagen, Germany.

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Authors and Affiliations

  1. Institute and Outpatient Clinic for Occupational and Environmental Medicine, Ludwig-Maximilians-University, Ziemssenstrasse 1, 80336, Munich, Germany

    Peter Angerer & Dennis Nowak

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  1. Peter Angerer
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Correspondence to Peter Angerer.

Appendix: Preliminary guidelines for an occupational health screening and surveillance examination for persons working in atmospheres with reduced oxygen concentrations for the purpose of fire prevention

Appendix: Preliminary guidelines for an occupational health screening and surveillance examination for persons working in atmospheres with reduced oxygen concentrations for the purpose of fire prevention

Area of applicability

Every individual who enters a room in which the oxygen concentration is reduced to ≤17% to ≥13% volume should be medically examined so that pre-existing diseases which would lead to health risks with hypoxia can be ruled out.

Types of examinations

Initial examination

Prior to working in an atmosphere with reduced oxygen concentration.

Follow-up examinations

While working in an atmosphere with reduced oxygen concentration.

Post-exposure examinations

Not applicable.

Initial examination

Screening

Medical history

General medical history, occupational history, and present medical complaints, should be determined. The history should then be taken in a structured format according to the questionnaire shown below. If one of the questions is answered with a 'yes', a supplementary examination should be performed.

History (medical questions directed at the patient):

  • Is there a family history of benign blood disease, inherited blood disease, low blood count, anemia, or sickle-cell disease?

  • Did you experience any pains (with the exception of headaches), such as abdominal, chest, or joint pains during previous stays at high altitude (mountains) or during airplane flights?

  • Have you ever felt sick with headaches, nausea, vomiting, shortness of breath or fatigue during previous stays at high altitudes (mountains) or during airplane flights?

  • Do you have any known heart disease?

  • Do you have any known lung or airway disease?

  • Do you have anemia?

  • Do you have sickle-cell disease?

  • Have you ever had a stroke or a stroke that improved (transient ischemic attack), or are you aware of any narrowing of the blood vessels in the neck?

  • Have you ever been treated for rhythm problems of the heart?

  • Have you had any episodes of dizziness within the last 3 months which have prevented you from pursuing your normal daily activities?

  • Have you ever been unconscious within the past year?

  • Do you have to pause during your daily activities at work or at home because of shortness of breath?

  • Do you have to pause to catch your breath while climbing a flight of stairs?

  • Has your physical performance decreased within the past 3 months?

  • Have you ever had any pain or pressure in your chest while under physical or mental stress?

  • Have you had any chest pain within the past month while at rest?

  • Have you woken up in the past 3 months because of shortness of breath?

Examination taking into account the actual working conditions

The physical examination should include at least the items described below; if a finding is not within the normal range, a supplementary examination should be performed.

Physical examination (questions directed at the physician):

  • Are there any pathological findings on examination of the respiratory tract or lungs, especially regarding:

    • Breathing pattern.

    • Respiratory frequency.

    • Inspection/percussion/auscultation of the lungs.

  • Are there any pathological findings on examination of the heart, circulation or arteries, especially regarding:

    • Jugular venous pressure?

    • Peripheral edema?

    • Frequency and rhythm of the heart?

    • Point of maximum impulse?

    • Auscultation of the heart?

    • Bruits in the carotid arteries?

    • Blood pressure (greater than 200/110 or below 100/60 mmHg)?

Special examination for the screening

Resting EKG: pathological changes should lead to additional investigations.

Complete blood count and peripheral blood smear: if erythrocyte indices reveal pathological changes supplementary investigations should be performed.

Laboratory:

  • Is the hemoglobin above or below the reference range of the specific laboratory?

  • Is the erythrocyte morphology pathological?

Supplementary examination

If the criteria of the screening are fulfilled (the examined individual answers the questions with a 'yes', or there is a pathological finding on physical examination or in the ECG or blood test) then a supplementary examination should be performed. This can be done by any physician who has the experience and technical equipment.

At least one of the following must be performed if the examination indicates a cardiac, circulatory or pulmonary disorder, or if anemia is present. The suspected disease determines which of the following investigations should be performed:

  • Exercise-ECG to determine cardiocirculatory performance and possibly to induce cardiac ischemia.

  • Spirometry to determine the FEV1.

  • Arterial or capillary blood-gas analysis to calculate the expected PaO2 in environments with reduced oxygen concentration (for formula for this calculation see Supplement 2).

  • Duplex ultrasonography if stenosis of an artery that supplies the brain is suspected.

  • Hemoglobin electrophoresis if sickle-cell disease is suspected.

Occupational health criteria

Ongoing medical concerns

For individuals with:

  • Coronary heart disease, hypertensive heart disease, cardiac valve disease with exercise-induced ischemia (e.g., stress- or exercise-induced angina pectoris, hypotension, typical EKG changes).

  • Chronic heart failure that leads to dyspnea or physical limitations with daily or work-related tasks. A further indication is a workload of less than 75 W in total or 1.5 W per kg bodyweight.

  • Respiratory tract and lung disease, chronic heart failure or anemia, who will have a PaO2 of <55 mmHg under hypoxic conditions as calculated from their PaO2 (see Supplement 2).

  • Signs of high-altitude illness, especially AMS, when previously exposed to hypoxia (Lake Louise Score including the question regarding sleeping disturbance ≥3, see Supplement 1). Such individuals should have a trial exposure. If the real working conditions lead to AMS (Lake Louise Score without the question regarding sleeping disturbance ≥3), then there are ongoing medical concerns.

  • Dizziness in the past 3 months that has affected daily activities.

  • High-grade (>70%) stenosis of the common or internal carotid arteries.

  • A stroke or a documented transient ischemic attack in the past. Such people should have a trial exposure. If symptoms such as dizziness, problems with concentration or confusion (or other neuropsychiatric symptoms) occur under these trial working conditions there should be ongoing medical concerns.

  • Sickle-cell disease. If there has been no sickle-cell crisis in the past, then a trial exposure is possible for a heterozygous individual. Further health risks are present only if this leads to signs of a sickle-cell crisis or hemolysis.

Temporary health concerns

Persons with the diseases listed in the section 'Ongoing medical concerns', above, as long as improvements are expected either spontaneously or with adequate treatment.

No health concerns if specific precautions are met

Individuals with the diseases listed in the section 'Ongoing medical concerns', above, if a medical examination is performed directly after a trial exposure to the specific working conditions and no negative medical effects can be determined.

No health concerns

All other persons.

Follow-up examinations

Time intervals for follow-up examinations

Initial follow-up examination

Within the first 3 years if oxygen concentrations are 15–13% vol.

Within the first 5 years if oxygen concentrations are >15–17% vol.

Further follow-up examinations

Within the first 3 years if oxygen concentrations are 15–13% vol.

Within the first 5 years if oxygen concentrations are >15–17% vol.

Earlier follow-up examinations

Are at the physician's discretion and may be scheduled if they allow more precise assessment of the risk due to the exposure. If the initial supplementary examination revealed an illness that would be relevant when the person was exposed to hypoxia (especially cardiac or pulmonary disease and anemia) then follow-up examinations should be performed within 3 months.

Scope of the follow-up examination

In general, only a medical history which especially considers complaints arising during exposure, and a screening physical examination are required (similar to the initial screening). Further examinations to clarify possible complaints related to the working environment are at the physician's discretion. If the supplementary examination reveals a disease that could lead to occupational medicine problems, then follow-up examinations are required according to the conditions listed in the 'Occupational health criteria' section above.

Occupational medicine criteria

See 'Occupational health criteria' above.

Post-exposure examinations

Not applicable.

Supplement 1

Lake Louise consensus: scoring of AMS

AMS self-assessment: the sum of the responses is the AMS self-report score. Headache and at least one other symptom must be present for the diagnosis of AMS. A score of 3 or more is taken as AMS. The question relating to sleep will not always be relevant, e.g., for assessing the effect of low oxygen concentration during a work shift.

Symptom

Scoring

Headache

0 None at all

1 Mild headache

2 Moderate headache

3 Severe headache, incapacitating

Gastrointestinal symptoms

0 Good appetite

1 Poor appetite or nausea

2 Moderate nausea or vomiting

3 Severe, incapacitating nausea and vomiting

Fatigue and/or weakness

0 None

1 Mild fatigue/weakness

2 Moderate fatigue/weakness

3 Severe fatigue/weakness

Dizziness/light-headedness

0 None

1 Mild

2 Moderate

3 Severe, incapacitating

Difficulty sleeping

0 Slept as well as usual

1 Did not sleep as well as usual

2 Woke many times, poor night's sleep

3 Could not sleep at all

see [88].

Supplement 2

Estimation of arterial oxygen tension during work in environments with reduced oxygen concentration

A regression formula has been developed to allow estimation of PaO2 at altitudes between 1,520 and 3,050 m in patients with COLD:

$$ {\rm{Predicted}}\;{\rm{PaO}}_2 = 22.8 - 2.74{\rm{x}} + 0.68{\rm{y}} $$

where x = expected altitude in thousands of feet; y = sea level PaO2 in mmHg).

Meter-to-feet conversion: m/0.3048 = feet [31].

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Angerer, P., Nowak, D. Working in permanent hypoxia for fire protection—impact on health. Int Arch Occup Environ Health 76, 87–102 (2003). https://doi.org/10.1007/s00420-002-0394-5

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