Transcript File - 911 Target & Medical Concepts LLC

Aviation Safety 2005
Aero Medical Briefing
Larry R Boehme, MD
Civil Aeromedical Institute
4/4/2016
Civil Aeromedical Institute
4/4/2016
Altitude Physiology
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
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Physics of the atmosphere
Respiratory physiology
Trapped gas
Required by FM-301
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aero medical training for flight personnel
4/4/2016
Air
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Air
What is it?
 Where is it?
 How do we use it as individuals?
 Why is it important in aviation safety?

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Altitude Physiology
Physics of the atmosphere
 Respiratory physiology
 Trapped gas

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Physics Of The Atmosphere
Definition and Boundary
• The atmosphere is a gaseous envelope that
covers the earth
• It extends from sea level up to 1000 nautical
miles
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Physics Of The Atmosphere
Gaseous Content
• Oxygen
- 20.95%
• Nitrogen
- 78.08%
• Trace Gases
- .97%
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Physics Of The Atmosphere
Atmospheric Pressure
• The weight of all atmospheric gases creating
a measurable force at any given point on the
surface of the earth
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Physics Of The Atmosphere
Atmospheric Pressure (continued)
• 14.7 psi
• 760 mm of Hg
• 29.92 inches of Hg
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Physics Of The Atmosphere
Benefits
• Provides Protection
• Supports animal and plant life
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Physics Of The Atmosphere
Divisions
• Troposphere
- Sea level to 30,000 feet at poles
- Sea level to 50,000 feet at the equator
• Tropopause
- Not considered a major division
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Physics Of The Atmosphere
Divisions (continued)
• Stratosphere
- Tropopause to 50 miles
• Ionosphere
- 50 miles to 600 miles
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Physics Of The Atmosphere
Divisions (continued)
• Exosphere
- 600 miles to 1000 miles
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Physics Of The Atmosphere
Physical Gas Laws
• Boyle’s Law
- A volume of gas is inversely proportional to the pressure exerted on the
gas, with temperature remaining constant
• Henry’s Law
- When the pressure over a liquid is decreased, the gas in the liquid will
also decrease
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Physics Of The Atmosphere
Physical Gas Laws (continued)
• Daltons’s Law
- The total pressure of a mixture of gas is equal to the sum of the partial
pressure of each gas in the mixture
• Graham’s Law
- A gas will defuse from an area of high concentration to an area of low
concentration
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Physics Of The Atmosphere
Physiological Zones
• Physiological Efficient Zone
- Ranges from sea level to 10,000 feet
• Physiological Deficient Zone
- Ranges from 10,000 feet to 50,000 feet
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Altitude Physiology
Physics of the atmosphere
 Respiratory physiology
 Trapped gas

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Respiration & Circulation
Definition of Respiration
• Respiration is the exchange of gases between
an organism and its environment
- Supplies body cells with Oxygen
- Removes Carbon Dioxide from cells
• Oxygen is used by the body for metabolism
- The burning of food material by the cells to produce energy
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Respiration & Circulation
3 Phases of Gas Exchange
• Atmosphere/Lungs
- External Respiration
• Lungs/Blood
- Internal Respiration
• Blood/Body Cells
- Cellular Respiration
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Respiration & Circulation
Respiratory System Components
• Oral/Nasal passages
• Trachea
• Bronchi
• Bronchial
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Respiration & Circulation
Respiratory System Components
(continued)
• Alveolar Ducts
• Alveoli
- Air Sacs
- 300 million
- Surrounded by capillaries
- 1 cell thick
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Respiration & Circulation
Internal Respiration
• An exchange of gases between the lungs and
blood
• All gas movement is dependent on the
difference in the partial pressure of that
particular gas
- Dalton’s Law
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Daltons’s Law
The Total Pressure of a Mixture of Gas Is Equal to
the Sum of the Partial Pressure of Each Gas in the
Mixture.
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Dalton’s Law
Ptotal = P1 + P2 + P3 ---
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Respiration & Circulation
Internal Respiration (continued)
• There are 4 major gases always present
in the lungs
- Nitrogen @ 573 mm of Hg
- Water Vapor @ 47 mm of Hg
- Carbon Dioxide @ 40 mm of Hg
- Oxygen @ 100 mm of Hg
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Respiration & Circulation
Internal Respiration (continued)
• Partial pressure of oxygen at sea level
maintains an arterial oxygen saturation
of 96% - 98%
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Respiration & Circulation
Internal Respiration (continued)
• High partial pressure of oxygen (100 mm)
diffuses through the air sac wall into the
blood
• High partial pressure of carbon dioxide
diffuses from the blood to the alveoli
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Respiration & Circulation
Circulatory System
• The circulatory system is responsible for
transportation of blood through out the
body
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Respiration & Circulation
Bloods Components
• Plasma
- 90% water
• Solids
- Primarily Red Blood Cells
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Respiration & Circulation
The Red Blood Cell (continued)
• The ability of the hemoglobin to become
oxygen saturated is dependent on alveolar
oxygen partial pressure
- Which is dependent on the ambient barometric pressure
• Normal oxygen saturation goes down as a
result of decreasing atmospheric pressure
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Respiration & Circulation
Cellular Respiration
• The exchange of gases between the blood
body cells
• Partial pressure of oxygen in the cells is
lower than the partial pressure of oxygen
in the blood
- Oxygen is off- loaded to the cells (Graham’s Law)
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Respiration & Circulation
Cellular Respiration (continued)
• Partial pressure of carbon dioxide in the cells
is higher than the partial pressure of carbon
dioxide in the blood
- Carbon Dioxide is off- loaded to the blood (Graham’s Law)
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Graham’s Law
A Gas Will Diffuse From an Area of High
Concentration to an Area of Low Concentration.
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Respiration & Circulation
Bloods Function
• Blood supplies each cell with
- Food
- Water
- Oxygen
• Blood transports waste material from cells
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Respiration & Circulation
The Red Blood Cell
• Responsible for transporting oxygen to
body cells
• Each red blood cell contains hemoglobin
- Contains iron
- Each red blood cell has over 250 million hemoglobin molecules
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Altitude Physiology
Physics of the atmosphere
 Respiratory physiology
 Trapped gas

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Trapped Gas
Intro to Trapped Gas
• Gases within the body are governed by
physical and chemical laws that describe
how a volume of gas changes in response
to changes in pressure and temperature
- Boyle’s Law
• Body cavities each have openings that
allow the gas to enter or exit
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Boyle’s Law
A Volume of Gas Is Inversely Proportional to the
Pressure Exerted on the Gas, With Temperature
Remaining Constant.
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Trapped Gas
Intro to Trapped Gas
• Problems arise when these openings are
reduced in size or closed, the gas is then
considered trapped
• Gas expansion occurs within the natural
gas cavities of the body that contains
varying amounts of gas
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Trapped Gas
Intro to Trapped Gas
• Gas cavities
- Middle Ear
- Sinuses
- Stomach and Intestines
- Teeth
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Trapped Gas
Ascending Phase
• During the ascending phase of flight
you more likely to develop problems
with the gastrointestinal tract, and on
rare occasions, the teeth
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Trapped Gas
Ascending Phase
• Gastrointestinal Tract
- Relieve by burping and passing gas
- Pilots should watch their diet and avoid foods that cause
excess gas formation
-
If you encounter any abdominal pain on ascent you should
a. Treat as soon as the symptoms appear
b. Relieve internal pressure by belching or passing gas
c. Massage affected area
d. Descend
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Trapped Gas
Ascending Phase
• With advances in modern dentistry,
problems with trapped gas in the teeth
are rare
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Trapped Gas
Ascending Phase
• Teeth
- Dental problems that can cause pain on ascent
a.
b.
c.
d.
-
A cavity
Bad dental work
An abscess
Swollen maxillary sinus from impacted wisdom tooth
Treatment
a. Land and see your dentist
b. Maintain a schedule of good dental hygiene
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Trapped Gas
Descending Phase
• During the descending phase you are
more likely to develop problems in
the middle ear and sinuses
• During descent as ambient pressure
increases, air must forcibly enter the
middle ear through the eustachian tube
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Trapped Gas
Descending Phase
• Middle Ear
- Normal ear clearing accomplished by
a. Swallowing
b. Exaggerated jaw movement
-
Upper respiratory infections may cause the eustachian
tube to become blocked
Middle ear block symptoms
a. Sensation of fullness
b. Minor hearing loss
c. Discomfort
d. Ringing in the ears
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Trapped Gas
Descending Phase
• Middle Ear
- Middle ear block symptoms (continued)
e.
f.
g.
h.
-
Pain
Dizziness
Nausea
Eardrum rupture
Middle ear block treatment
a. Yawning
b. Swallowing
c. Chewing
d. Perform a Valsalva
e. Climb
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Trapped Gas
Descending Phase
• Sinuses blockage can occur on ascent
or descent, however, problems are more
likely to occur on descent
• The most commonly affected sinuses are
the frontal and maxillaries
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Trapped Gas
Descending Phase
• Sensation of fullness may or may not
appear before the onset of pain
• Onset rate can occur faster than
middle ear problems and can be
incapacitating
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Trapped Gas
Descending Phase
• Sinuses
- Sinus block treatment
a.
b.
c.
d.
Level off from descent
Perform a Valsalva maneuver
Gradual descent
Stair step down
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