AvMed Flashcards
Knowllege of aviation medicine
what is the composition of the atmosphere
atmosphere 0-300,000 ft
21% Oxygen, 79% nitrogen and trace of CO2 and other gases (Argon and Ozone)
Atmosphere pressure is approx 1000mb at sea level and the partial pressure of Oxygen is 160mm HG (Mercury)
what is the pressure of oxygen at sea level, 8000 and 16000ft
sea level 160 mm Hg
8000ft 118.7 mm Hg
18000ft 79.8 mm Hg
In other words the atmosphere becomes less dense as we climb and the result is the partial pressure of oxygen at 18000 ft is 1/2 of that at sea level.
What causes the onset of hypoxia
altitude duration rate of ascent physical exertion cold
‘the rate of its affect depends on how it is induced’
hypoxia general
body sensitive to deprivation of oxygen (either in quality or partial pressure)
25% reduction in oxygen pressure (equivalent to 8,000ft cabin alt) produces detectable impaired mental performance
what are the symptoms of hypoxia
flushed cyanosis increase rate of breathing gas expansion tingling sensations (pins and needles) light headedness ear discomfort impaired judgement vision and motor skills
what is the time of useful consciousness
Rapid decompression at the maximum altitude for the A400M is around 15-30 seconds
the higher you go the lower the time gets
how long would you stay conscious without any oxygen to the brain
6-8 seconds
4 mins irreversible damage
how can you treat somebody with hypoxia
put on 100% Oxygen as soon as possible at a low cabin altitude
what is respiration
the exchange of oxygen through the lungs in to the blood
precautions to be taken during pressure changes
keep trying to clear your ears
otherwise you could end up with what is known as ‘ear block’ or ‘ottic barotrauma’
don’t eat too much gas forming foods
don’t fly for 24 hours after dental work
cavities in the body that contain gas
sinuses (expand and contraction of Eustachian Tube) Middle ear cavities (as above) teeth fillings guts joints
what are the dangers with flying with a head cold
can’t clear ears and equalise pressure in the eustachian tube
Noxious substances- routes of entry into the body
Inhalation ingestion Skin absorption inoculation injection
actions in the event the cockpit contamination
immediately run the smoke and fumes drill and don FFQDM 100% oxygen
fit FFQDM to portable bottle
what are the causes of hyperventilation
excessive ventilation causing an imbalance of CO2
caused by:
anxiety (fear of flying)
normal response to hypoxia
rise in temperature
pressure breathing
what are the symptoms of hyperventilation
tingling
unreality
dizziness
muscle spasms
how to treat somebody who is hyperventilating
put on 100% Oxygen as soon as possible at a low cabin altitude
Breathe through pursed lips, as if you are whistling, or pinch one nostril and breathe through your nose. It is harder to hyperventilate when you breathe through your nose or pursed lips, because you can’t move as much air.
what is the bends (decompression sickness)?
too many nitrogen bubbles in the body expanding due to exposure of lowered atmospheric pressure.
Can be affect those that have recently dived using aqualung or have conducted ground pressurisation tests (GE)
how to treat the bends (decompression sickness)
100% Oxygen at as low a cabin alt as possible
lay flat of possible
what are the symptoms of the bends
aching muscles or joints tingling of skin muscle weakness poor coordination loss of sensation confusion pain collapse
rapid decompression
passengers masks auto deploy at 14000 ft in normal mode
or 16000 ft in high mode
masks can be manually deployed from the load master workstation or the flight deck
causes of rapid decompression
failure of the airframe
failure of the pressurisation system
Why do oxygen bottles last longer at altitude?
When you’re in a high-altitude environment, the barometric pressure causes air molecules to expand, so each breath you take contains fewer oxygen molecules. Oxygen Plus products directly solves this “large air molecule” problem by instantly delivering pure enriched oxygen to your cells
medical flying restrictions
inoculations, and vaccinations- normally 12 hour restriction
general, spinal or epidural- 48 hours
acupuncture- SMO authority 12 hours
hypnotherapy- SMO authority plus nil flying while under treatment
donating blood- 36 hours
eye dialated- 24 hours
pressurisation- 12 hours after aqualung
24 hours of more than 10 metres
12 hours after ground pressurisation
