Hypoxia

◦ Emotional change and disorder
4000m: the beginning of emotional change, euphoria(欣快 症) Depression 6000m: Paroxysm(情绪爆发)

Sensing system ◦ Optesthesia(视觉) Night vision 1500m: vision disorder
because of inadequate blood flow.

Results from ◦ The oxygen-rich blood in the lungs is not moving to the tissues that need it. ◦ Shock
Circulatory shock, commonly known simply as shock, is a life-
◦ Muscle spasms
◦ Nausea ◦ Sleepiness
◦ Unconsciousness

Hyperventilation symptoms are very similar to that of Hypoxia

Check oxygen equipment for proper function Breathe normally



5000m: significant physiological disorder
5500m: unconsciouseness in people without training in high altitude 6000m: consciousness may exist, but has been in the state of function loss 7000m: unconsciouseness in the overwhelming majority, only few people trained can endure a short period

The alveolar pressure will not decrease until few minutes
exposure

Mild hypoxia —— no symptoms in rest state Moderate hypoxia —— symptoms even in rest state

Reduction of oxygen supply to a tissue below
physiological levels
despite adequate perfusion of the tissue by blood.

Classified as ◦ Fulminating altitude hypoxia ◦ Acute altitude hypoxia

Results from
◦ Reduced blood volume (such as severe bleeding)
◦ Certain blood diseases (such as anemia)
CO poisoning

Failure to transport sufficient oxygen
◦ Chronic altitude hypoxia

Altitude hypoxia with rapid and severe progression

People can endure for few seconds or few minutes

Hypoxia induced by suddenly exposed to low atmosphere pressure in high altitude

Dangerous area
◦ altitude higher than 7000m
◦ Dead if without protective treatment

Subjective symptoms is mild because of the hypoxia in brain

Symptoms vary between individuals

Sensing system
◦ Acouesthesia(听觉)
◦ Touch and algesia(痛觉)

Circulation system ◦ Vasovagal syncope(血管迷走性晕厥)

Describes the maximum time the pilot has to make rational, lifesaving decisions and carry them out at a given altitude without
For every increase 600m of altitude, vision decreases 5%
Day vision 5500m: vision disorder
Spatial vision
3000m: few people, mild disorder 5000m: majority, disorder 7000m: all people, marked disorder

Results from tissue poisoning
◦ Alcohol ◦ Narcotics ◦ Cyanide ◦ Other poisons (such as H2S)

The blood is not able to take up and transport a sufficient amount of oxygen to the cells in the body.
start to breathe very quickly

Histotoxic hypoxia（组织中毒缺氧） Hypemic hypoxia (贫血性缺氧)
Stagnant hypoxia （停滞性缺氧）

Altitude hypoxia
(高空性缺氧)

The inability of cells to take up or utilize oxygen from the bloodstream, despite physiologically normal delivery of oxygen to such cells and tissues.
supplemental oxygen
◦ Varies with altitude

Altitude ◦ the higher, the shorter the time

Rate of ascent
◦ increase rate, decrease
EPT

Physical activity
◦ exercise decreases EPT

Severe hypoxia —— unconsciousness

Hypoxia induced by exposed in mild or moderate low pressure
atmosphere in a long duration, that is few days, few years, or

Abnormal oxygenation
◦ Hypoxia: a condition in which the body or a region
of the body is deprived of adequate oxygen supply

Abnormal ventilation
◦ Hyperventilation: a condition in which you suddenly
threatening medical condition that occurs due to inadequate
substrate for aerobic cellular respiration. In the early stages, this is generally an inadequate tissue level of oxygen.

Immediately use supplemental oxygen
◦ System on, Mask on, breathe normally

Check operation of oxygen equipment ◦ Don’t wait for problems

Make emergency descent if oxygen is not available

Cause
◦ Emotional tension or stress
◦ Fear or anxiety ◦ Pain
◦ Pressure breathing equipment

Symptoms ◦ Dizziness ◦ Hot & / or cold sensations ◦ Tingling of hand, legs, or feet
◦ If problem was hypoxia, symptoms disappear rapidly

Hyperventilation symptoms are very similar to hypoxia symptoms
Symptomless area Compensation area Dysfunction area Dangerous area

Symptomless area
◦ altitude less than 3000m