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1

What height is considered to be the Physiological Zone?

MSL - 10000feet

2

What height is considered to be physiologically deficient zone?

10000-50000 feet

3

What is considered to be the Space Equivalent Zone?

50000 feet and above

4

What is the break down of the atmosphere?

78% Nitrogen
21% Oxygen
1% other gases (ozone, CO2, methane etc)

5

Does the percentage of gases in atmosphere change?

No, pressure may change but percentage relationship stays the same

6

What height is pressure approximately half that of atmosphere?

18000 feet

7

What is hypoxia?

Lack of 02 to tissue sufficient to cause impairment of function

8

What are the four types of hypoxia?

Hypoxic hypoxia (due to low o2 levels)
Anaemic Hypoxia (insufficient blood)
Stagnant (lack of flow, g force)
Histotoxic hypoxia (poison)

9

At 33000 feet on 100% oxygen, what is this equivalent to?

Sea level on air

10

At 40000 feet on 100% oxygen, what is this equivalent to?

10000 feet on air

11

What are some signs of hypoxia?

Tingling cyanosis
Loss of judgement
Loss short term memory
Slower reaction times
Mental 'Tunnel vision"
Hot flushes, (cherry cheeks)
Sense of euphoria
Muscular in-coordination and tremors
Loss of peripheral, colour and night vision

12

What factors will increase risk of hypoxia?

Rate of ascent
Exercise/fitness (lack there of)
Illness/cold
Fatigue
Drugs and alcohol (hangover)
Smoking
Stress/workload

13

How do you 'recover' from hypoxia?

O2 mask, 100% oxygen
Descend below 10000 feet
Breathe normal rate and depth
Declare emergency
Land ASAP

14

What is oxygen paradox?

Worsening of symptoms following re-introduction of O2 after period of exposure to hypoxia

15

What is you useful level of conciousness at FL180?

20-30 minutes

16

What is your useful level of conciousness at FL250?

3-5 mins

17

What is your useful level of conciusness at FL300?

1-2mins

18

What is your useful level of conciusness at FL350?

30-60 seconds

19

What is your useful level of conciusness at FL400?

15-30seconds

20

What is your useful level of conciusness at FL430?

9-12 seconds

21

What are some post hypoxic symptoms?

Fatigue
Headache
Lethargy

22

What are some causes of hyperventilation?

Hypoxia
Vibration
Pain
Excessive G forces
Anxiety/fear/stress
Motion sickness
Voluntary over breathing
Environmental stressors (high temperatures)

23

What are some symptoms of hyperventilation?

Dizziness
Lightheaded
Sensory changes
Tingling
Apprehension
Unconsciousness then recovery

24

What are some body cavities that contain gas?

Teeth
Lungs
Gastrointestinal tract
Middle ear
Sinuses
Post op sites

25

Gas expansion in lungs can lead to what illnesses?

Pneumothorax
Air embolism (air bubbles)
Pnemomediastinum

26

What can lead to gas expansion in the lungs?

Pressure changes and holding your breath

27

When is pain in the ears likely to occur?

During descent

28

Where in the ear are you likely to feel affects of pressure change?

Middle ear (known as barotrauma)

29

Why do we feel pain in the ear?

Air cannot easily escape Eustachian tube to equalise pressure

30

What are the four sinuses

Ethmoidal
Sphenoidal
Frontal
Maxillary