Hypoxia AHF 2203 Puan Rosdalila Roslan. Gases of the atmosphere.
Post on 26-Dec-2015
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Gases of the atmosphere
Nitrogen78%
Oxygen20.9%
1.1% ARGON, CO2, NEON,HELIUM,
KRYPTON,XENONHYDROGEN,
AMMONIA
Standard Pressure/Temp With The Increase Of Altitude
Altitude (ft) Pressure (mm/Hg) Temperature (o C)
0 760 15.0
18,000 380 -5.3
34,000 190 -62.3
48,000 95 -67.3
63,000 47 -67.04
Definition
Hypoxia means "reduced oxygen" or "not enough oxygen“. Most concern is with getting enough oxygen to the brain. Any reduction in mental function while flying can result in life-threatening errors.
Causes
Hypoxia can be caused by several factors including:
a) insufficient supply of oxygen, b) inadequate transportation of oxygen, or c) the inability of the body tissues to use
oxygen.
•Hypoxic hypoxia is a result of insufficient oxygen available to the lungs.
•Although the percentage of oxygen in the atmosphere is constant, but pressure decreases proportionately as atmospheric pressure decreases. This situation leads to only fewer molecules available at the pressure required for them to pass between the membranes in the respiratory system.
Reduced pO2 in the lungs(high
altitude)
Body tissue
Red blood cells
Hypoxic HypoxiaA
deficiency in
Alveolar oxygen
exchange
•This occurs when the blood is not able to take up and transport a sufficient amount of oxygen to the cells in the body.
•Hypemic means "not enough blood." This type of hypoxia is a result of oxygen deficiency in the blood, rather than a lack of inhaled oxygen, and can be caused by a variety of factors.
An oxygen deficiency
due to reduction
in the oxygen
carrying capacity of the blood
+
+
+
+
++
+
++
+
+
+
+ ++
Hypemic Hypoxia
Low-
Haem
oglobin
•Stagnant hypoxia results when the oxygen-rich blood in the lungs isn't moving, for one reason or another, to the tissues that need it.
•An arm or leg going to sleep because the blood flow has accidentally been shut off is one form of stagnant hypoxia.
•This kind of hypoxia can also result from shock, the heart failing to pump blood effectively, or a constricted artery.
Causes:
•During flight, stagnant hypoxia can occur when pulling excessive positive Gs.
•Cold temperatures also can reduce circulation and decrease the blood supplied.
Reduced bloodflow
Blood movingslowly
Adequateoxygen
Red blood cells not
replenishing tissue needs fast enough
Stagnant Hypoxia
G-
Forc
es
•The inability of the cells to effectively use oxygen is defined as histotoxic hypoxia.
•In this case, plenty of oxygen is being transported to the cells that need it, but they are unable to make use of it.
Causes:
•This impairment of cellular respiration can be caused by alcohol and other drugs, such as narcotics and poisons.
•Research has shown that drinking one ounce of alcohol can equate to about an additional 2,000 feet of physiological altitude.
Red blood cells retain oxygen
Inability of the
cell to accept or use oxygen
Poisoned tissue
Adequateoxygen
Histotoxic Hypoxia
Alcohol
The common symptoms of hypoxia:
• Cyanosis (blue fingernails and lips) • Headache • Decreased reaction time • Impaired judgment • Euphoria • Visual impairment • Drowsiness • Light-headed or dizzy sensation • Tingling in fingers and toes • Numbness
As altitude increases above 10,000 feet, the symptoms of hypoxia increase in severity, and the time of useful consciousness rapidly decreases.
Symptomology & Altitude Frequency of Occurrence
5,000 ft 10,000 ft 15,000 ft 18,000 ftBlurred vision Hyperventilation Belligerence Cyanosis
Tunnel vision Impaired task management
Euphoria Confusion
Decreased night vision
Air hunger Sleepiness Poor judgment
Apprehension Slow thinking Muscle coordination
Fatigue
Headache
Dizziness
Numbness / Tingling
•Avoid alcohol and smoking•Healthy Diet•Good physical condition•Lower altitudes•Avoid temperature extremes•Slower Climb rates
•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
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