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is a medical condition in which the tissues of the body are deprived of the necessary levels of oxygen due to an insufficient supply of oxygen, which may be due to the composition or pressure of the breathing gas, decreased lung ventilation, or respiratory disease, any of which may cause a lower than
255:
While breathing pure oxygen at ambient pressure, from an oxygen cylinder or other source, the maximum altitude a human can tolerate while their body is at atmospheric pressure is 13,700 metres (45,000 feet), , where atmospheric pressure is about 14.7kPa. This is a function of the partial pressure of
117:
Hypoxia can result from various causes which can be categorised as: anemic hypoxia, cellular hypoxia, generalised, or hypoxic hypoxia, pulmonary hypoxia, stagnant hypoxia, increased oxygen consumption due to a hypermetabolic state, or any combination of these. The three fundamental causes of hypoxia
472:, where the main dysfunction is in the cardiovascular system, causing a major reduction in perfusion. Arterial gas is adequately oygenated in the lungs, and the tissues are able to accept the oxygen available, but the flow rate to the tissues is insufficient. Venous oxygenation is particularly low.
347:
Generalized hypoxia is an effect of a lack of oxygen, and in many cases of a one-time event can be reversed simply by eliminating the lack. Where there is no underlying pathology, provision of oxygen at normobaric partial pressure (about 0.21 bar) is usually sufficient to reverse minor symptoms.
422:
Hypoxemic hypoxia is a low oxygen tension in the arterial blood, due to the inability of the lungs to sufficiently oxygenate the blood. Causes include hypoventilation, impaired alveolar diffusion, and pulmonary shunting. This definition overlaps considerably with that of hypoxic
256:
oxygen in the breathing gas, and is also dependent on level of exertion which affects the oxygen requirements of metabolism, cardiovascular fitness, and acclimatization to altitude which affects the available hemoglobin and can vary significantly between individuals.
101:, although the two conditions often occur simultaneously, since a decrease in blood oxygen typically corresponds to a decrease in oxygen in the surrounding tissue. However, hypoxia may be present without hypoxemia, and vice versa, as in the case of
118:
at the tissue level are low oxygen content in the blood (hypoxemia), low perfusion of the tissue, and inability of the tissue to extract and use the oxygen in the blood. Generalised, or hypoxic hypoxia may be caused by:
332:
Severe hypoxia can cause loss of consciousness, seizures or convulsions, coma and eventually death. Breathing rate may slow down and become shallow and the pupils may not respond to light.
199:
502:(Dysoxia) occurs when oxygen is transported to the tissues but they cannot use it effectively because the cells cannot extract oxygen from the blood. This is seen in cyanide poisoning.
81:
normal oxygen content in the arterial blood, and consequently a reduced supply of oxygen to all tissues perfused by the arterial blood. This usage is in contradistinction to
85:, in which only an associated group of tissues, usually with a common blood supply, are affected, usually due to an insufficient or reduced blood supply to those tissues.
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Above 3000 metres (10,000 feet) - ambient pressure 69.7kPa, about 14.6kPa partial pressure of oxygen – enough hypoxic stimulation to cause increased ventilation
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may occur in the initial phases. Later, the heart rate may reduce significantly degree. In severe cases, abnormal heart rhythms may develop.
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can improve saturation of oxygen in the blood which will stop hypoxia if it is caused by hypoxemia, i.e. low levels of oxygen in the blood.
136:
Low-inspired oxygen partial pressure, which may be caused by breathing air at low ambient pressures due to altitude, by breathing hypoxic
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occurs when the lungs receive adequately oxygenated gas which does not reach the blood in sufficient quantities. It may be caused by:
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hypoxia or hypemic hypoxia is the lack of capacity of the blood to carry the normal level of oxygen. It can be caused by anemia or:
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Breath-hold diving. Proceedings of the
Undersea and Hyperbaric Medical Society/Divers Alert Network 2006 June 20–21 Workshop
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Above 7600 metres (25,000 feet) - ambient pressure 37.6kPa absolute, 7.9kPa partial pressure of oxygen – consciousness lost
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913:. Washington, DC: Flight Standards Service. Federal Aviation Administration, U.S. Dept. of Transportation. 2001.
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When breathing the ambient air at high altitudes (above 3048 metres/10,000 feet), the human body experiences
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Where there is a pathology causing the hypoxia, treatment of the underlying pathology is often effective.
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occurs when the cells are unable to extract sufficient oxygen from normally oxygenated hemoglobin.
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Physiological mechanisms involved in the risk of loss of consciousness during breath-hold diving
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at an unsuitable depth, by breathing inadequately re-oxygenated recycled breathing gas from a
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Manninen, Pirjo H.; Unger, Zoe M. (2016). "Hypoxia". In
Prabhakar, Hemanshu (ed.).
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Lindholm, Peter (2006). Lindholm, P.; Pollock, N. W.; Lundgren, C. E. G. (eds.).
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may be caused by abnormally low blood flow to the lungs, which can occur during
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19:"Hypoxic hypoxia" redirects here. For other uses of the term "hypoxia", see
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may be required where the person is unable to breathe sufficiently unaided.
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Decreased reaction time, disorientation, and uncoordinated movement.
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Impaired judgment, confusion, memory loss and cognitive problems.
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Pilot's
Handbook of Aeronautical Knowledge: FAA Manual H-8083-25
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by mask or nasal tubes may be provided to treat chronic hypoxia.
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followed by lowered blood pressure as the condition progresses.
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125:– failure of the respiratory pump due to any cause (fatigue,
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of oxygen, decreasing the carriage of oxygen by hemoglobin.
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Above 3700 metres (12,000 feet) - 64.4kPa, about 13.52kPa P
571: – Chemical element with symbol O and atomic number 8
556: – Medical condition of lack of oxygen in the tissues
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Above 5500 metres (18,000 feet) - 50.6kPa, about 10.6kPa P
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Bhutta, B.S.; Alghoula, F.; Berim, I. (9 August 2022).
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550: – Abnormally low level of oxygen in the blood
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950:"Hypoxia and hyperbaric oxygen therapy: a review"
714:South Pacific Underwater Medicine Society Journal
398:that can dilate the airways may be used to treat
781:. Durham, NC: Divers Alert Network. p. 26.
736:. Archived from the original on August 8, 2009
710:"Some limitations of semi-closed rebreathers"
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383:chronic obstructive pulmonary disease
198:Malformed vascular system such as an
185:Chronic obstructive pulmonary disease
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689:. Treasure Island, FL: StatPearls .
872:Mandal, Ananya (17 February 2010).
827:"Hypoxia: Management and Treatment"
594:Mandal, Ananya (17 February 2010).
369:Continuous positive airway pressure
948:Choudhury, R. (20 November 2018).
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371:(CPAP) mask may be used to treat
642:Complications in Neuroanesthesia
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379:Bilevel positive airway pressure
292:Lightheaded or dizzy sensation,
97:, which refers to low levels of
93:This is not to be confused with
470:abdominal compartment syndrome
433:Ventilation perfusion mismatch
417:Other types of medical hypoxia
89:is also used as a synonym for
1:
645:. Academic Press (Elsevier).
381:(BIPAP) may be used to treat
335:Tingling in fingers and toes
238:– first irritability appears
907:"17: Aeromedical Factors".
220:and hypoxemia due to a low
105:. Several other classes of
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190:Neuromuscular diseases or
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753:: CS1 maint: unfit URL (
482:Carbon monoxide poisoning
200:anomalous coronary artery
192:interstitial lung disease
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466:congestive heart failure
412:in and around the lungs.
21:Hypoxia (disambiguation)
708:Elliott, David (1997).
651:10.1016/C2015-0-00811-5
831:my.clevelandclinic.org
408:may be used to reduce
402:or other lung disease.
363:Artificial ventilation
59:hypoxia warning system
127:barbiturate poisoning
1006:Respiratory diseases
967:10.2147/IJGM.S172460
878:www.news-medical.net
600:www.news-medical.net
446:Circulatory hypoxia
389:Supplemental oxygen
357:hyperbaric medicine
309:Shortness of breath
146:life support system
99:oxygen in the blood
87:Generalized hypoxia
78:Generalized hypoxia
32:Generalized hypoxia
874:"Hypoxia Symptoms"
521:. You can help by
500:Histotoxic hypoxia
260:Signs and symptoms
164:Airway obstruction
150:anesthetic machine
788:978-1-930536-36-4
660:978-0-12-804075-1
554:Hypoxia (medical)
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487:Methemoglobinemia
427:Pulmonary hypoxia
325:Initially raised
288:Visual impairment
248:– severe symptoms
218:altitude sickness
212:Altitude sickness
154:hypoxia of ascent
83:localized hypoxia
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749:cite journal
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322:and vomiting
314:Palpitations
305:or tiredness
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131:pneumothorax
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960:: 431–442.
883:27 November
836:27 November
605:27 November
563:Pulmonology
373:sleep apnea
71:Pulmonology
37:Other names
794:24 January
740:2008-06-14
576:References
303:Drowsiness
210:See also:
158:freediving
142:rebreather
103:infarction
726:0813-1988
687:"Hypoxia"
548:Hypoxemia
464:, severe
406:Diuretics
343:Treatment
181:function
179:pulmonary
177:Abnormal
95:hypoxemia
67:Specialty
1000:Category
986:30538529
734:16986801
695:29493941
542:See also
423:hypoxia.
396:steroids
394:Inhaled
338:Numbness
282:Euphoria
271:Headache
266:Cyanosis
172:drowning
977:6251354
299:Fatigue
294:vertigo
168:choking
133:, etc.)
109:exist.
984:
974:
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569:Oxygen
476:Anemic
400:asthma
320:Nausea
187:(COPD)
113:Causes
61:, 1963
775:(PDF)
720:(1).
468:, or
458:shock
410:edema
152:, or
148:, or
982:PMID
915:ISBN
885:2022
838:2022
796:2017
783:ISBN
755:link
730:OCLC
722:ISSN
691:PMID
655:ISBN
607:2022
355:and
57:for
972:PMC
962:doi
647:doi
525:.
452:or
156:in
1002::
980:.
970:.
958:11
956:.
952:.
893:^
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