Altitude Physiology Flashcards
What is the mean temperature lapse rate?
2*C/1000’
What is the standard atmospheric pressure measurement at sea level at 59*F?
29.92 In/Hg
760 mm/Hg
What are the physiological zones of the atmosphere?
The efficient zone: sea level to 10,000’
The deficient zone: 10,000 to 50,000’
The space equivalent zone: 50,000’ and up
What is hypoxia?
The state of O2 deficiency in the blood cells and tissues significant enough to cause impairment function
What are the types of hypoxia?
Hypoxic
Histotoxic
Hypemic
Stagnant
What is hypoxic hypoxia?
Occurs when there is not enough O2 in the air. Usually experienced at altitudes above 10000’
What is hypemic hypoxia?
The reduction in blood’s O2 carrying capacity, usually from anemia or blood loss
What is stagnant hypoxia?
O2 carrying capacity if adequate, but circulation is inadequate, usually from heart failure or high G maneuvers
What is histotoxic hypoxia?
Inability of the body’s tissue to use O2, usually from alcohol or cyanide
What are signs and symptoms of hypoxia?
Signs are effects on the body that other people can witness such as cynaosis or lack of muscle coordination
Symptoms are subjective and something someone feels such as fatigue, headache, blurred vision
What are some things that make indivduals susceptible to hypoxia?
Physiological altitude: a body’s perceived altitude. Things like tobacco and alcohol increase the PA.
Smoking 3 cigarettes in rapid succession or 20-30 cigarettes with 24 hours before a flight can put a smoker at a PA of 5000’ and reduce night vision by 20%
1oz of alcohol can have a PA of 2000’
What are the stages of hypoxia?
Indifferent: 98-90% O2, 0-10000’
Compensatory: 89-80% O2, 10000-15000’
Disturbance: 79-70% O2, 15000-20000’
Critical: 69-60% O2, 20000’ and up
How do you prevent hypoxia?
Limit time at altitude, use supplemental O2, pressurized cabin
How do you treat hypoxia?
Give individual 100% O2 and descent below 10000’
