Flight Physiology

Question 1

Boyles Law

Answer 1

•As altitude increases, atmospheric pressure decreases, and gas in an enclosed container expands(Boyles Balloon)

P1 V1=P2 V2

Question 2

Charles Law

Answer 2

•Atmospheric pressure is constant
•Proportional relationship w/ Temp & Vol.
•q 1000’ elevation Temp decreases 2C
•q 150m elevation Temp decreases 1C

Question 3

Daltons Law

Answer 3

•Total pressure of gas mixture is the sum of partial pressure of all gases.

Also describes how pressure affects partial pressures of a gases at certain altitudes.

How to apply
Increase FIO2(concentration of O2)

Question 4

Henrys Law (Soda can)

Answer 4

•The amount of gas dissolved in a solution is directly proportional to the pressure exerted by gas over the solution.

How to apply
Place gas under pressure(BVM or Vent)

Question 5

Ficks Law

Answer 5

•Rate of diffusion of a gas across a membrane is determined by: chemical nature of membrane, surface area, partial pressure gradient, and thickness of membrane.

How to apply
Change surface area(add peep)

Question 6

Grahams Law (Equality)

Answer 6

•Rate of diffusion is proportional to the square root of its molecular weight.

*Lighter gas diffuses faster than heavier gas
*Gases move from higher to lower concentration until equality is achieved.

Question 7

Atmospheric pressure at sea level

Answer 7

760mmHg or 760 torr

*equal to 1 atmosphere(ATM)
*Barometric pressure is the same thing but in a different unit of measurement(inHg).
Ex: Barometric pressure at sea level is 29.92inHg

Question 8

of feet below sea level to gain 1 atmosphere?

Answer 8

For q 33’ below sea level you gain 1 atmosphere

Question 9

P1V1=P2V2(solving for V2)

P1V1/P2=V2

Answer 9

P1- starting ATM @ lowest altitude
V1- starting volume of container
P2- highest ATM based on highest altitude
V2- Ending volume as impacted by the highest altitude

Question 10

Barotitis Media

Answer 10

Ear pain

Test question
During descent!

Question 11

Barosinusitis

Answer 11

Pain in sinuses

*Ascension problem

Question 12

Barobariatrauma (the Bends)

Answer 12

•Acts like decompression sickness
•Seen in obese patients(fat holds onto Nitrogen)
•Nitrogen Narcosis during ascension
•Ascension problem
•Tx is high flow O2

Question 13

Barodentalgia

Answer 13

Tooth pain(ascent problem)
Stop the flight and go to the dentist ASAP

Question 14

Gay-Lusaacs Law

Answer 14

*Charles brother
•Temp and volume affect the pressure exerted on the sides of a container.

Question 15

Difference between PaO2 & PAO2

Answer 15

•PAO2= partial pressure of O2 in Alveoli
•PaO2= partial pressure of O2 in arterial blood

Question 16

D.E.A.T.H.

Answer 16

Drugs
Exhaustion
Alcohol
Tobacco
Hypoglycemia

Question 17

Stressors of Flight

Answer 17

•Hypoxia*
•Barometric pressure
•Thermal changes
•Decreased humidity
•Noise
•Vibration
•Fatigue
•Gravitational forces
•Flicker vertigo(dizziness)—5-20Hz
•Spatial disorientation

Question 18

Effects & symptoms of Hypoxia
(Subjective)

Answer 18

•Fatigue
•Anxiety
•Nausea
•HA
•Dizziness
•Denial
•Numbness/Tingling
•Hot & cold flashes
• Agitation
•Blurred vision
•Euphoria

Question 19

Effects & Symptoms of Hypoxia
(Objective)

Answer 19

•Hyperventilation
•Confusion
•Poor decision making
•Cyanosis
•Lack of coordination
•Unconsciousness

Question 20

Indifferent stage of Hypoxia(1)

Answer 20

•0-10k’
•SPO2 90-98%
•Decrease in night vision @ 4k’
• increase in HR & RR
•Unaware of symptoms
smokers lose 20% of night vision @ sea level(physiological altitude of 5k’

Question 21

Compensatory Stage of Hypoxia(2)

Answer 21

•10-15k’
•SPO2 80-90%
•Advanced stage 1 symptoms
•Night vision < 50%
•CNS symptoms:
-poor judgement
-Irritable
-Drowsy
-Decrease coordination

Question 22

Disturbance stage of Hypoxia(3)

Answer 22

•15-20k’
•SPO2 70-80%
•Senses:Vision, Touch, Pain, Hearing
•CNS: Memory, judgement, reliability, understanding.
•Personality: Happy drunk vs mean drunk
•Psychomotor function: coordination, flight control, speech, handwriting.
•Signs: hyperventilation and cyanosis

Question 23

Critical stage of Hypoxia(4)

Answer 23

•20-25k’
•SPO2 60–70%
•Inability to remain upright
•Jerking upper limbs
•Seizures
•Rapid unconsciousness
•Coma & death

Question 24

Time if useful consciousness(explosive decompression)

Answer 24

> 40k’ —Single digit seconds. The shortest time interval answer possible

Question 25

Calculate desired O2 per altitude

Answer 25

*PaO2 decreases by 5mmHg for q 1k’ increase in altitude.

Calculation: (%FIO2xP1)/P2=FIO2 at new altitude.

P1- current barometric pressure
P2- new barometric pressure at altitude
(Altimeter and Barometric pressure are the same)

Question 26

Quiz question:
an ARDS patient with the current SPO2 of 85% is being transferred. The current FiO2 via the mechanical ventilator is set at 50%. The current referring hospitals elevation is approximately sea level. The pilot advises the highest altitude you will be flying at will be 5000 feet. Using the following information calculate the required FiO2 change needed based on the desired FiO2 by altitude formula.

Answer 26

Answer:
FI02 @new altitude=(%FiO2xP1)/P2
P1=current barometric pressure
P2= new barometric pressure at altitude

Question 27

Quiz question:
If the atmospheric pressure at 18,000 feet MSL is 380 torr, what is the partial pressure of oxygen at that altitude?

Answer 27

As we ascend an altitude, the concentration of O2 remains the same however, the decrease in atmospheric pressure also decreases the partial pressure of oxygen.
380 TORR x 0.21 = 79 PaO2

Question 28

Quiz question:
When administering high concentrations of oxygen to alleviate hypoxic hypoxia, you are altering, which component of which gas law?

Answer 28

Answer:
Giving high concentrations of O2 is affecting Henry’s law and the solubility of oxygen diffusion. Henry’s law affects the concentration, solubility, and pressure that oxygen molecules need to be placed under to diffuse more rapidly into the solution.

Question 29

Quiz question:
A patient suffering from decompression sickness is an example of which gas law?

Answer 29

Answer: Henry’s law