Exam Revision Flashcards
(159 cards)
What height is considered to be the Physiological Zone?
MSL - 10000feet
What height is considered to be physiologically deficient zone?
10000-50000 feet
What is considered to be the Space Equivalent Zone?
50000 feet and above
What is the break down of the atmosphere?
78% Nitrogen
21% Oxygen
1% other gases (ozone, CO2, methane etc)
Does the percentage of gases in atmosphere change?
No, pressure may change but percentage relationship stays the same
What height is pressure approximately half that of atmosphere?
18000 feet
What is hypoxia?
Lack of 02 to tissue sufficient to cause impairment of function
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)
At 33000 feet on 100% oxygen, what is this equivalent to?
Sea level on air
At 40000 feet on 100% oxygen, what is this equivalent to?
10000 feet on air
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
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
How do you ‘recover’ from hypoxia?
O2 mask, 100% oxygen Descend below 10000 feet Breathe normal rate and depth Declare emergency Land ASAP
What is oxygen paradox?
Worsening of symptoms following re-introduction of O2 after period of exposure to hypoxia
What is you useful level of conciousness at FL180?
20-30 minutes
What is your useful level of conciousness at FL250?
3-5 mins
What is your useful level of conciusness at FL300?
1-2mins
What is your useful level of conciusness at FL350?
30-60 seconds
What is your useful level of conciusness at FL400?
15-30seconds
What is your useful level of conciusness at FL430?
9-12 seconds
What are some post hypoxic symptoms?
Fatigue
Headache
Lethargy
What are some causes of hyperventilation?
Hypoxia Vibration Pain Excessive G forces Anxiety/fear/stress Motion sickness Voluntary over breathing Environmental stressors (high temperatures)
What are some symptoms of hyperventilation?
Dizziness Lightheaded Sensory changes Tingling Apprehension Unconsciousness then recovery
What are some body cavities that contain gas?
Teeth Lungs Gastrointestinal tract Middle ear Sinuses Post op sites