Transcript High Altitude Physio..

High Altitude Physiology
and Human Factors
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October 4, 2006
Introduction
Define the atmosphere in terms of its characteristics
and human adaptability.
Describe how gases in our bodies will respond to
changes in the environment, and how this impacts
our performance.
Review causes and hazards of hypoxia and
hyperventilation
As we ascend
The combination of pressure
and oxygen percentage
determine our ability to
perform.
What altitudes do you first
notice effects?
Our environment changes…
predictably,
gradually,
to the point where we are in
a hostile environment,
and well beyond our ability
to adapt and survive.
HYPOXIA
Types of Hypoxia and Causes
• Hypoxic
• Histotoxic
• Hypemic
• Stagnant
Hypoxic Hypoxia
A lack of oxygen partial pressure in the lungs or a reduction in
the gas exchange area caused by:
Altitude
Drowning
Pneumonia
Chronic Lung Disease
Location of Impediment
Lungs
Hypoxic hypoxia is the most common cause of hypoxia for a
pilot due to an oxygen deficiency associated with high altitude
operations
Effective Performance Times
Time of Useful Consciousness
FL180
20-30 minutes
FL220
8-10 minutes
FL250
3-5 minutes
FL300
1-2 minutes
FL350
30-60 seconds
FL430
9-12 seconds
FL500 and above
9-12 seconds
Effective Performance Times
should always be a
consideration.
At 25,000 feet, the maximum
altitude of the Cirrus, the
time of useful
consciousness is about 3-5
minutes.
It is extremely important to
continually monitor the
oxygen system at be
prepared to deal immediately
with any oxygen
malfunction.
Histotoxic Hypoxia
The lack of oxygen intake into the cell (tissue
poisoning) caused by:
Alcohol
Narcotics
Location of Impediment
Cells
Histotoxic hypoxia is dependent on factors other
than altitude.
Hypemic Hypoxia
Inability of the blood to carry oxygen caused by:
Carbon Monoxide Poisoning
Smoking
Fire creates toxins that can irritate and incapacitate
Anemia
Location of Impediment
Blood
Carbon monoxide and smoking create an oxygen
carrying deficiency which will degrade pilot
performance
Stagnant Hypoxia
Lack of proper blood distribution caused by:
“G” forces
Shock, fainting, etc.
Heart Failure
Cold Temperature
Location of Impediment
Blood Transportation Problem
Steep turns at FL250 may not be a good idea
Subjective Symptoms
Air Hunger
Headache
Nausea
Hot & Cold Flashes
Euphoria
Tingling
Apprehension
Dizziness
Fatigue
Blurred Vision
Tunnel Vision
Numbness
Objective Signs
Mental Confusion
Increase in rate and depth of
breathing
Cyanosis
Belligerence
Poor Judgment
Loss of muscle coordination
Euphoria
Unconsciousness
Factors influencing hypoxia
Altitude
Individual Tolerance
Environmental Temperature
Psychological Factors
Alcohol/Smoking
Rate of Ascent
Physical Activity
Duration of Exposure
Physical Fitness
Medications
Rate of Decompression
Prevention
Use oxygen in compliance with the regulations
15,000 MSL Crew must use Oxygen, and must be provided to each occupant
14,000 MSL Crew must use Oxygen for flights duration
12,500 MSL Crew must use Oxygen after 30 min
Prevention and Considerations
Use of pulse oximeter
Adjust the flow of oxygen
to maintain saturation
levels above 90%
Cannulas vs Masks
Cannulas can not be
used above FL180 as per
FAR part 23
Remember where the
source of oxygen is from
when using a cannula.
Eating and talking will
decrease the amount of
oxygen that is available
to your lungs
Prevention and Considerations
Passengers
Monitor passengers for
signs of hypoxia and
treat accordingly
Passengers should be
briefed on the use of
oxygen during preflight
When to use start using
oxygen?
Treatment for Hypoxia
Recognition of hypoxia
100% Oxygen
Return Rate and Depth of
Breathing to Normal
Check Connections
Check adjustment and size of
mask
Descend Below 10,000 feet
Terrain permitting
SCREAM
Supply
Connections
Regulator
Emergency connection
Adjustment
Mask condition
Hyperventilation
Hyperventilation
An abnormal increase in the
rate and depth of breathing.
Results in exhaling too
much Carbon Dioxide.
Voluntary
Emotional
Fear
Anxiety
Stress
Tension
Pain
Pressure Breathing
Hypoxia
Subjective Symptoms
Dizziness
Faintness
Visual Problems
Tingling
Nausea
Light Headedness
Objective Signs
Muscle Twitching
Cold, clammy skin
Muscle Tightness
Paleness
Unconsciousness
Hypoxic Hypoxia - Hyperventilation
Comparison
Signs
Hyperventilation
Hypoxia
Onset
Gradual
Varies with altitude
Muscle Activity
Spasm
Flaccid
Skin Appearance Pale, Clammy
Cyanosis
Tetany
Present
Absent
Dizziness
X
X
Euphoria
X
X
Fatigue
X
X
Headache
X
X
Poor Judgment
X
X
Light headiness
X
X
Tingling
X
X
Treatment for
Hyperventilation
100% Oxygen
Return Rate and Depth of
Breathing to Normal
Check Connections
Paper Bag Method
Used at altitude where
supplemental oxygen is
not required or needed
Talk or sing to control the
rate of breathing.
Other Physiological Affects of
Altitude/Pressure Change
Decompression sickness
Caused by the formation of nitrogen
bubbles in the blood and tissues
following a sudden drop in the
surrounding pressure, as when
ascending rapidly.
Characterized by severe pains in the
joints and chest, skin irritation,
cramps, and paralysis
Treatment
Decompression sickness is a
medical emergency, respond
appropriately.
NOTE: Time between scuba diving
on non-decompression stop dives
and flying is 12 hours. The minimum
time between decompression stop
diving and flying is 24 hours.
Other Physiological Affects of
Altitude/Pressure Change
Sinus/inner ear blockage
Caused by the difference
in pressure from the
middle ear and the
outside world, most likely
due to a cold, ear
infection or a sore throat.
Treatment
On descent, level off
and Valsalva
Reverse direction of
pressure change
Retry Valsalva
Use reduced rates of
descent and land
The eustachian tube allows air pressure to
equalize in the middle ear.
Conclusion
Remember the atmosphere that we live in is much
different up at altitude than it is down on the surface.
As a pilot you must be prepared for any
physiological situation that may arise.
You must be able to recognize the symptoms of
Hypoxia and Hyperventilation as well as be able to
take the appropriate action in order to prevent
conditions from getting worse.
Physiological Training
UNDAF Altitude Chamber
FAA Physiological Training
Highly recommended
Experience conditions that
can lead to hypoxia
Learn to recognize hypoxia
Learn about other
physiological limitations
when flying