Atmosphere and respiration

Question 1

boyles law

Answer 1

V inversely proportional to P

associated with barotrauma

Question 2

guy lussac law

Answer 2

volume const

P proportional to T

Question 3

combined gas law

Answer 3

PV/T=k

Question 4

ficks law

Answer 4

diffusion
high concentration to areas of low concentration
inversely proportional to thickness of membrane

Question 5

daltons law

Answer 5

total pressure is equal to sum of the partial pressures

related to hypoxia

Question 6

henrys law

Answer 6

more pressure, more gas can dissolve into a liquid directly proportional
related to decompression sickness

Question 7

external respiration

Answer 7

occurs at lungs
between 12-20 breaths per minute at rest

Nose warms ,moistens & filters air

Question 8

tidal volume

Answer 8

air inhaled & exhaled in normal breath

500ml

Question 9

inspiratory reserve volume

Answer 9

extra can inhale above normal

3100ml

Question 10

expiratory reserve volume

Answer 10

extra can exhale above normal

1200ml

Question 11

residual volume

Answer 11

not all air breathed out. what’s left in lungs

1200ml

Question 12

total lung capacity

Answer 12

all volumes added

Question 13

vital capacity

Answer 13

max can actually breath in or out

everything but residual

Question 14

functional residual capacity

Answer 14

expiratory reserve + residual

Question 15

inspiratory capacity

Answer 15

tidal volume + inspiratory reserve

Question 16

altitude at which oxygen partial pressure of O2 drops to 1/2?

Answer 16

10000ft

drops to 55mmHg

Question 17

altitude at which total pressure drops to 1/2?

Answer 17

18000ft

380mmHG

Question 18

altitude at which total pressure drops to 3/4?

Answer 18

8000ft

543mmHg

Question 19

altitude at which total pressure drops to 1/4?

Answer 19

36000ft

187mmHg

Question 20

total pressure at MSL?

Answer 20

760mmHg

Question 21

when oxygen partial pressure drops below 55mmHg…

Answer 21

alveoli no longer cope
above 10000ft
percentage of ox remains same but partial pressure decreases

Question 22

haemoglobin saturation levels

Answer 22

SL- 97%
10000ft- 87%
20000ft- rapidly falls to 65%
saturation less than 90% can result in hypoxia

Question 23

2 types of hypoxia

Answer 23

hypoxic- due to decrease in partial pressure of oxygen from increase in alt
anaemic- inability of blood to carry oxygen

Question 24

what makes hypoxia worse?

Answer 24

smoking 
high workload at altitude 
unhealthy,alcohol, diet etc
higher alt= worse 
exposure

Question 25

hypoxia reaction threshold

Answer 25

GL- 7000ft
vision sensory affected as low as 5000ft
newer task/ memory affected
dark adaption affected

Question 26

hypoxia disturbance threshold

Answer 26

7000-12000
increased blood pressure -
increased heart rate -
maintaining homeostasis

Question 27

hypoxia critical threshold

Answer 27

12000-22000ft
homeostasis doesn't work
euphoria
cyanosis
fornication
dizziness
headache
impaired judgement 
muscular impairment 
hyperventilation 
mental performance degraded to 12000ft
memory impaired 12000ft
confusion
grey out / tunnel vision
incapacitation 
loss of consciousness 
DEATH

Question 28

TUC & EPT

Answer 28

time of useful consciousness

effective performance time- time you can perform flying duties effectively in reduced oxygen

Question 29

TUC

Answer 29

20k- 30 min, mod activity- 5min
30k- 1-2min
35k- 30-90sec
40k- 15-20sec

halved for smokers

Question 30

hyperventilation

Answer 30

lung ventilation in excess of bodies needs
too much CO2 removed from the blood
less carbonic acid - go into respiratory alkalosis
can lead to hypoxia - vasoconstricts vessels

Question 31

causes of hyperventilation

Answer 31

stress
anxiety
travel sickness - motion sickness 
high Gs
shock 
high or low acid level

Question 32

hyperventilation symptoms

Answer 32

seizures
tingling light headed
hot or cold flushes 
headache 
lethargy
sickness
muscle spasm 
confusion
increased heart rate

Question 33

hyperventilation treatment

Answer 33

breathe into paper bag

hold one nostril

Question 34

decompression sickness

Answer 34

formation of nitrogen in bubbles after decompression at altitude 
18000-25000ft
unlikely below 14000ft
symptoms:
bends- in joints 
chokes- in lungs
staggers- in brain

made worse by: high alt, age, obesity, worse if been scuba diving

prevent with pre oxygenation - 100% ox flushes out nitrogen

Question 35

rules about scuba diving and flying

Answer 35

must not fly within 12 hours of swimming with compressed air
if exceeding 30ft(10m) don’t fly within 24hours
not applicable to snorkelling

Question 36

decompression and hypoxia treatment

Answer 36

don mask- 100%ox
declare emergency
controlled but rapid descent 
land ASAP
on landing seek medical advice 

can get decompression symptoms 24 hours after so wait to fly again- can be treated in decompression chamber

prevent with pre oxygenation

Question 37

hypoxia or hyperventilation

Answer 37

unsure then always treat for hypoxia as its worse
hyperventilation- recover after unconsciousness
hypoxia - die after unconsciousness

below 10000ft hypoxia unlikely so maybe treat for hyperventilation but be aware

Question 38

oxygen requirements

Answer 38

MSL-10000ft normal air
10000ft - 33700ft- cab pressure, supplementary air/oxygen mix, keeps body at MSL
33700-40000ft - cabin alt, 100% oxygen, keeps body at 10000ft
above 40000ft- pressurised 100%, keeps body at 10000ft

Question 39

cabin pressure

Answer 39

kept between 6000-8000ft