Aeromedical Flashcards
What is hypoxia?
The body’s lack of oxygen.
What are the types of hypoxia?
Hypoxic hypoxia
Histotoxic hypoxia
Stagnant hypoxia
Hypemic hypoxia
What is Hypoxic hypoxia?
When there is not enough oxygen in the air or when decreasing atmospheric pressure prevents diffusion of oxygen from the lungs to the bloodstream.
What is Hypemic hypoxia?
A reduction in blood’s oxygen-carrying capacity.
What is Stagnant hypoxia?
The blood’s oxygen-carrying capacity is adequate but circulation is inadequate.
What is Histotoxic hypoxia?
An interference with the use of oxygen by body tissues.
Where are you most likely to encounter Hypoxic hypoxia?
At high altitudes due to the reduction of PO2 in the atmosphere.
What causes Hypemic hypoxia?
Anemia and blood loss are the most common causes, but other possible causes include exposure to carbon monoxide, nitrites, and sulfa drugs, which form compounds with and reduce the amount of hemoglobin available to combine with oxygen.
What causes Stagnant hypoxia?
Conditions such as heart failure, arterial spasm, and blood vessel occlusion predispose affected individuals. It often occurs when a crewmember experiences extreme gravitational forces and blood flow is disrupted, causing blood to stagnate.
What causes Histotoxic hypoxia?
Alcohol, narcotics, and certain poisons such as cyanide interfere with a cell’s ability to use an adequate supply of oxygen.
What are the signs(objective) of hypoxia?
Hyperventilation Cyanosis Mental confusion Poor judgement Lack of muscle coordination
What are the symptoms(subjective) of hypoxia?
Increased breathing rate Apprehension Fatigue Headache Dizziness Hot and cold flashes Euphoria Belligerence Blurred vision Tunnel vision Numbness Tingling
What is the Time of Useful Consciousness for each altitude in table 2-6.
18,000 - 20-30 minutes 22,000 - 8-10 minutes 25,000 - 4-6 minutes 35,000 - 30-60 seconds 43,000 - 9-12 seconds >50,000 - 9-12 seconds
How is the Time of Useful Consciousness affected in a pressurized aircraft that loses cabin pressurization(rapid decompression)?
An individual has only one-half the TUC.
What are the %s of oxygen saturation, altitudes, and symptoms associated with each stage of Hypoxic hypoxia?
+Indifferent - (98%-90%) - 0-10,000 - Decreased night vision
+Compensatory - (89%-80%) - 10,000-15,000 - Drowsiness; poor judgment; impaired coordination and efficiency
+Disturbance - (79%-70%) - 15,000-20,000 - Impaired flight control, handwriting, speech, vision, intellectual function, and judgement; decreased coordination, memory, and sensation to pain
+Critical - (69%-60%) - 20,000-25,000 - Circulatory and central nervous system failure; convulsions; cardiovascular collapse; death
