04. Hypoxia, Hyperventilation, Acceleration Flashcards
Hypoxia, Hyperventilation, Acceleration
What are the 3 types of hypoxia
- HYPOXIC HYPOXIA
- ANAEMIC HYPOXIA
- HISTOTOXIC HYPOXIA
- Anaemic Hypoxia stems from lack of oxygen carrying capacity
- Histotoxic Hypoxia occurs at a cellular level. The cell is impaired and cannot use the oxygen
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What is the cause of hypoxic hypoxia
LOW HAEMOGLOBIN OXYGEN SATURATION
- Typically for pilots this is caused by reduced level of atmospheric oxygen
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The amount of oxyhaemoglobin in the blood depends on thea mount of oxygen in what
THE LUNGS
- This explains why low atmospheric pressure can caue hypoxia
- External air pressure can change the proporition of gases in the lungs
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The amount of oxygen in the air when factoring in the other gases that form total pressure is described as what and is measured in what unit
- PARTIAL PRESSURE
- mm Hg
- At sea level, atmospheric pressure is 760 mm Hg, but only 160 mm Hg of this is oxygen
- Oxyten partial pressure at sea level would therfore be 160 mm Hg
- Daltons law ~ Pt = P1 + P2 + P3
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What happens to the partial pressure of oxygen in the atmosphere as altitude increases
FALLS
- Does not fall at a constant rate
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What is the partial pressure of oxygen in the lungs at sea level
103 mm Hg
(14.5% of air in the lungs)
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Which 2 other gases in the lungs remain at a relatively constant partial pressure as altitude increases, subsequently reducing further the partial pressure of oxygen in the lungs as altitude increases
- CARBON DIOXIDE (CO2)
- WATER VAPOUR
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What are the 3 physiological thresholds of hypoxia and their altitudes
- REACTION - 7,000 ft
- DISTURBANCE - 10,000 - 12,000 ft
- CRITICAL - 22,000 ft
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“beyond this threshold is where yo being to see a definite reaction from the body to lower levels of oxygen saturation in the blood and performance of complex tasks may be impaired. A slight increase in both breathing and heart rate is detected”
This is a definition of which Hypoxia threshold and height in feet
REACTION THRESHOLD
7,000 ft
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“breathing air produces significantly lower sats and the bodys defence mechanisms begin to generate cardiovasulat and respiratory responses to give some protection against hypoxia. Beyond this threshold the body struggles to cope and even a relatively short exposure duration will result in impaired judgement, memory and alertness.”
This is a definition of which Hypoxia threshold and height in feet
DISTURBANCE THRESHOLD
10,000 - 12,000 ft
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“Beyond this threshold sats fall as low as 65-60% and mental performance quickly deteriorates, with a rapid onset of extreme dizziness and confusion. Total loss of consciousness and complete incapacitation will follow without warning”
This is a definition of which Hypoxia threshold and height in feet
CRTICAL THRESHOLD
22,000 ft
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Above what altitude will night vision adaptation start to be affected in regards to symptoms of hypoxia
5,000 ft
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What is one of the first symptoms of someone suffering from hypoxia
DEGRADED MENTAL PERFORMANCE
performance of complex tasks may be impaired
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What are 4 initial symptoms of hypoxia above the disturbance threshold altitude of 10,000 - 12,000 ft
[ ] EUPHORIA
[ ] JOINT PAIN
[ ] FATIGUE
[ ] DIZZINESS
[ ] PANTING
[ ] HUNGER
[ ] HEADACHE
[X] EUPHORIA
[ ] JOINT PAIN
[X] FATIGUE
[X] DIZZINESS
[ ] PANTING
[ ] HUNGER
[X] HEADACHE
- EUPHORIA
- FATIGUE
- DIZZINESS
- HEADACHE
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A pilot should not operate above what altitude without the use of supplementary oxygen
10,000 ft
Hypoxia, Hyperventilation, Acceleration
Complete the table for oxygen requirements
Up to 10,000 ft | ? |
10,000 - 33, 700 ft | ? |
33,700 - 40,000 ft | ? |
Above 40,000 ft | ? |
Altitude | Requirement |
Up to 10,000 ft | No specific requirement
10,000 - 33,700 ft | Increasing percentage of supplement oxygen required
33,700 - 40,000 ft | 100% O2 required
Above 40,000 ft | Pressurised 100% O2 required
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By what altitude is 100% oxygen required to maintain the partial pressure of oxygen to that of sea level
33,700 ft
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Hypoxia DOES or DOES NOT lead to shortage of breath
DOES NOT
- Panting does not occur which is a normal symptom of lack of oxygen
- This is because there is no excess of carbon dioxide, just a shortage of oxygen
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Which body organ is the largest consumer of oxygen and the first to be affected by hypoxia
BRAIN
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Hypoxia affects the brain first. If conditions persist beyond the first initial symptoms, 7 other functions/symptoms may appear are;
[ ] VISION
[ ] APPETITE
[ ] JUDGEMENT
[ ] MOTOR SKILLS
[ ] DROWSINESS
[ ] NEED FOR BATHROOM
[ ] SPEECH
[ ] MEMORY
[ ] PANTING
[ ] CONCENTRATION
[X] VISION
[ ] APPETITE
[X] JUDGEMENT
[X] MOTOR SKILLS
[X] DROWSINESS
[ ] NEED FOR BATHROOM
[X] SPEECH
[X] MEMORY
[ ] PANTING
[X] CONCENTRATION
- Difficulty in concentrating
- Degradation of reasoning and perceptive functions
- Impaired judgement, mood changes, euphoria
- Drowsiness, light headedness, dizziness, nausea and lethargy
- Loss of muscular coordination
- Pallow and syanosis - blueing of the extremities
- Failure of the basic senses, especially colour vision
- Unconsciousness
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The severity of hypoxia can depend based on what 4 things
- RATE OF DECOMPRESSION
- PHYSICAL FITNESS
- FLIGHT LEVEL
- INDIVIDUAL TOLERANCE
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Hypoxia onset can be hastened by the which of 6 following factors
[ ] Exercise
[ ] Short Sightedness
[ ] Weight
[ ] Cold
[ ] Being ill
[ ] Height
[ ] Fatigue
[ ] Drug/Alcohol use
[ ] Diet
[ ] Smoking
[X] Exercise
[ ] Short Sightedness
[ ] Weight
[X] Cold
[X] Being ill
[ ] Height
[X] Fatigue
[X] Drug/Alcohol use
[ ] Diet
[X] Smoking
- EXERCISE
- COLD
- ILLNESS
- FATIGUE
- DRUGS & ALCOHOL
- SMOKING
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Smoking reduces the ability o transfer oxygen by what percentage
4 - 10%
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A heavy smoker can become hypoxic at and above what altitude
6,000 ft
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“the length of time during which an individual can act with both mental and physical efficiency and laertness”
This is the definition of what in relation to hypoxia
TIME OF USEFUL CONSCIOUSNESS
(TUC)
Hypoxia, Hyperventilation, Acceleration
The TUC varies with altitude. Completed the following table;
ALTITUDE | SEATED (at rest) |
1. ____ ft | ____ min
2. ____ ft | ____ min
3. ____ ft | ____ sec
4. ____ ft | ____ sec
Time of Usful Consciousness
- 20,000ft | 30 min
- 30,000 ft | 1-2 min
- 35,000 ft | 30-90 seconds
- 40,000 ft | 15-20 seconds
Hypoxia, Hyperventilation, Acceleration
What is the altitude range of cabin altitude
6,000 - 8,000 ft
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What does EPT stand for
EFFECTIVE PERFORMANCE TIME
(EPT)
- The pilots ability to function regardless of consciousness
- TUC may be 30 seconds, but EPT may only be 15 seconds
- EPT is always less than TUC
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How long should aircrew wait before flying after donating blood
24 HOURS
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Hyperventilation can lead to a reduction of what in the blood, which changes the acid balance in what
- CO2
- PLASMA
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The state of beathing faster and/or deeper than is necessary for the body is known as what
HYPERVENTILATION
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Hyperventilation may be caused by what 2 elements specifically which make up a sub list of actual reasons i.e. stress and anxiety, or heat and vibration
- PSYCHOLOGICAL
- PHYSIOLOGICAL
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What are the 8 identifiable symptoms of hyperventilation
[ ] DIZZINESS
[ ] EUPHORiA
[ ] TINGLING OF EXTREMITIES
[ ] VISUAL DISTURBANCES
[ ] FLUSHES
[ ] IRRITABILITY
[ ] ANXIETY
[ ] NAUSEA
[ ] IMPAIRED PERFORMANCE
[ ] LOSS OF CONSCIOUSNESS
[ ] RAPID BREATHING RATE
[X] DIZZINESS
[ ] EUPHORiA
[X] TINGLING OF EXTREMITIES
[X] VISUAL DISTURBANCES
[X] FLUSHES
[ ] IRRITABILITY
[X] ANXIETY
[ ] NAUSEA
[X] IMPAIRED PERFORMANCE
[X] LOSS OF CONSCIOUSNESS
[X] RAPID BREATHING RATE
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A prolonged case of hyperventilation can cause the suffer to exhibit servere muscle contractions of the limb extremities. This is known as what
CARPOPEDAL SPASMS
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What is the name given when the syhmpathetic nervous system releases extreme levels of adrenaline in response to anxiety or stress
PANIC ATTACK
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What is the best method to control hyperventiliation
POSITIVELY CONTROLLED BREATHING
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What symptom is associated to hypoxia, but not with hyperventilation, which is a blueing of extremities
CYANOSIS
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What is the cause of anaemic hypoxia
REDUCED ABILITY FOR BLOOD TO CARRY OXYGEN
lack of oxygen carrying capacity
- Blood loss such as a wound, or donating blood
- Smoking, which prevents oxygen binding to Haemoglobin
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“the lack of oxygen carrying capacity. May be caused by blood loss or smoking”
This is a definition of what sort of hypoxia
ANAEMIC HYPOXIA
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“occurs at a cellular level. Although there is an adequate supply of oxygen, cells are unable to accept or use it”
This is a definition of what sort of hypoxia
HISTOTOXIC HYPOXIA
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What are the 6 key characteristic symptoms of DCS
decompression sickness
- THE BENDS
- THE CREEPS
- THE CHOKCES
- THE STAGGERS
- LOSS OF VISION
- PARALYSIS OF LIMBS
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“Embolisms in capillaries IN THE BRAIN with disturbances in walking, neurological side effects”
This is a definition of what symptom of DCS
decompression sickness
THE STAGGERS
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“Embolisms in THE CAPILLARIES Feeling of ants crawling under your skin”
This is a definition of what symptom of DCS
decompression sickness
THE CREEPS
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“Embolisms in THE JOINTS intense arthritis type pain”
This is a definition of what symptom of DCS
decompression sickness
THE BENDS
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“Embolism in THE LUNGS Chest pain and coughing slowly increasing in severity, with deep breahting Usually associated with divers in rapid ascents”
This is a definition of what symptom of DCS
decompression sickness
THE CHOKES
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Hypoxia, Hyperventilation, Acceleration
A pilot must not fly after scuba diving for how long in the following conditions;
- Shallow diving using compressed air : ____ hrs
- Depth greater than 30 ft : ____ hrs
- 12 hours
- 24 hours
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If a passenger or crew member is showing symptoms of DCS, what action must the pilot take
DESCEND IMMEDIATELY
Descend until the symptoms are no longer evident
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Decompression sickness (DCS) is unlikely to occur at altitudes of less than ____ ft
14,000 ft (padpilot)
18,000 ft (BGS)
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Above ____ ft the risk of DCS is significantly increased
25,000 ft
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A reduction in ____ pressure causes ____ to form in the blood plasma which contributes to decompression sickness
- AMBIENT PRESSURE
- TINY NITROGEN BUBBLES
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Tiny nitrogen bubbles merge together to create larger bubbles known as what
AIR EMBOLISMS
Hypoxia, Hyperventilation, Acceleration
What is the treatment for decompression sickness
COMPRESSION CHAMBER 100% OXYGEN AND KEPT WARM
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What are the 2 immediate actions that should be taken, in order, following the loss of pressurisation
- DON OXYGEN MASK (100% oxygen)
- DESCEND (below 10,000 ft)
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In a rapid decompression, the cabin altitude may be ____ft HIGHER or LOWER than the actual altitude
- 5,000 ft
- HIGHER
- This is as a result of the venturi effect
- Air is sucked out of the cabin resulting in a lower pressure
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Following a rapid decompression event, due to the delay of onset of decompression sickness, aircrew should wait how long before flying again
24 HOURS
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What does G-LOC stand for
G-INDUCED LOSS OF CONSCIOUSNESS
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In an aircraft, when is the human body subjected to angular accelerations
PITCHING UP and DOWN
(Z axis)
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In an aircraft, when is the human body subjected to linear accelerations
INCREASE or DECREASE IN AIRSPEED
(X axis)
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In an aircraft, when is the human body subjected to Radial accelerations
LEVEL TURN
(Y axis)
- Looping is considered radial also, but would incur the angular acceleration at first also as the climb or descent were to begin
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Someone who is fit and wearing protective g suit clothing can sustain consciousness and vision up to ____g
An unprepared person or someone unwell will become unconscious at ____g
- 7 - 8g
- 4g
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Under negative G, where does the blood pool
FEET or HEAD
HEAD
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1.Positive G is caused by PITCH UP or PITCH DOWN
2. Negative G is caused by PITCH UP or PITCH DOWN
- PITCH UP
- PITCH DOWN
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The body can tolerate exposure to a G of as much as ____Gz in the verticle axis
+25Gz
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Hypoxia, Hyperventilation, Acceleration
As forces approach ____Gz, a lack of blood to what 2 organs will start to cause ‘grey out’ and ultimately lead to unconsciousness
- +3.5Gz
- EYES
- BRAIN
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7 major factors which affect the tolerance to G are what;
[ ] ALTITUDE
[ ] POSTURE
[ ] AGE
[ ] ACTIVE MEASURES
[ ] EXPERIENCE
[ ] EQIPMENT
[ ] HEALTH
[ ] AIRCRAFT TYPE
[ ] SPEED OF ONSET
[ ] DURATION
[ ] ALTITUDE
[X] POSTURE
[ ] AGE
[X] ACTIVE MEASURES
[X] EXPERIENCE
[X] EQIPMENT
[X] HEALTH
[ ] AIRCRAFT TYPE
[X] SPEED OF ONSET
[X] DURATION
- POSTURE : height difference
- ACTIVE MEASURES : tensing abdominal muscles as example
- EXPERIENCE : frequent practice
- EQUIPMENT : Anti-g trousers as example
- HEALTH : unfit or unwell
- SPEED OF ONSET : time to react
- DURATION : prolonged exposure
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Shorter people are MORE or LESS tolerant to vertical G
MORE
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What are the 4 stages of hypoxia
- INDIFFERENT
- FULL COMPENSATION
- INCOMPLETE COMPENSATION
- CRITICAL
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Hypoxia, Hyperventilation, Acceleration
Complete the stages of hypoxia table;
STAGE | ALTITUDE |
1. INDIFFERENT | ____ft AMSL
2. FULL COMPENSATION | ____ ft AMSL
3. INCOMPLETE COMPENSATION | ____ ft AMSL
4. CRITICAL | ____ ft AMSL
- INDIFFERENT | 0 - 5,000 ft AMSL
- FULL COMPENSATION | 5,000 - 12,000 ft AMSL
- INCOMPLETE COMPENSATION | 12,000 - 20,000 ft AMSL
- CRITICAL | Above 20,000 ft AMSL
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