CFRN Exam Questions with Correct Answers| Latest Update Guaranteed Success
What is atmospheric pressure at sea level? 760mmHg (or 760 torr)
T/F: Atmospheric pressure and barometric pressure are essentially the same thing, just using a
different unit of measure. True (think measuring same item in inches and then measuring it
in cm)
How many atmospheres (or ATMs) are at sea level? 1 atmosphere/ATM at sea level
What is barometric pressure? The combined weight of all atmospheric gases creating a force
upon the surface of the earth.
What is barometric pressure at sea level? 29.92Hg
According to Boyle's law, as altitude increases, barometric pressure ____, and gas in an
enclosed space ____ as long as temperature remains ____. decreases, expands, constant
T/F: As altitude increases, the measurement of Atmospheres (ATMs) also increases. False -
decreases
Quick math for calculating drop in ATMs until appx 5000/6000 feet altitude is that for every
____ increase in altitude, ATM goes down 5%. 1500 feet
What do the values of P1V1=P2V2 for Boyles law mean? P1 = starting ATM at the lowest
altitude
V1 = starting volume (ETT cuff, epigastrum, etc.)
P2 = highest ATM based on highest altitude
V2 = ending volume as impacted by highest altitude
*constant temperature*
,Due to Boyle's law, what type of physiologic process/pain may you experience on descent?
barotitus media - can't equalize ears (for test: only clinical issue that occurs on descent,
sinusitis ascent)
In barobariatrauma, according to boyles law, as altitude increases and atmospheric pressure
drops - the drop causes ____ to be displaced off of phospholipids and ____ narcosis can occur.
nitrogen, nitrogen
T/F: Barobariatrauma acts like a decompression sickness, such as a scuba diver who rapidly
ascends. True (would also be seen on ascent phase of flight)
Barobariatrauma is more common in what type of population of patients? morbidly obese
How is nitrogen narcosis from barobariatrauma treated? High flow O2 (preferably appx 15
minutes before flight if concerned this may present - morbidly obese, significant altitude
changes)
Barodentalgia (think boyles law) occurs in which phase of flight? ascent
According to Charles's law, if pressure is constant, what is the relationship of volume and
temperature? directly proportional (temp up = volume up, temp down = volume down)
(*think car tires*)
For every 1000' increase in altitude, how much will the temperature decrease? 2 degrees
celsius (if in meters - 150 meters ascent = 1 degree celsius temp decrease)
Which gas law states the following: At a given mass and constant volume of gas, the pressure
exerted on the sides of its container is directly proportional to its absolutely temperature.
Gay-Lusaac's law
,How many gases make up atmospheric air? 5 (nitrogen being the most, oxygen second)
What gas law states the sum of the partial pressure in a mixture of gases will equal the total
pressure? Dalton's law
A mix of Dalton's and Boyle's law concepts would conclude that as altitude ______,
atmospheric pressure decreases. Even though the pressure changes, the gas stays at the ____
proportions. Therefore, if increasing altitude, the partial pressure of oxygen (amount available
in atmosphere) will ___. increases, same, decrease
How do you calculate a partial pressure of oxygen? Oxygen in mmHg x oxygen concentration
Ex: 760mmHg (sea level) x 0.21 (normal O2 % in air) = 159.6mmHg (partial pressure aka
available amount of oxygen in atmosphere)
Normal paO2 on ABG? 80-100 (partial pressure of oxygen or amount of oxygen
measured/available in arterial blood)
What gas law states that the amount of gas dissolved in a solution is directly proportional to the
pressure of the gas on the surface of the solution? Henry's law
(think if you turn up FiO2 and there is more partial pressure of oxygen, more will be dissolved
Into the solution - or think pop can, CO2 under pressure in can escapes proportionately when
can is opened and pressure released)
When the alveoli are perfused with blood as normal, but ventilation/oxygenation fails to supply
the perfused region Shunting (may often be caused by some sort of blockage - PE, infectious
process/fluid)
One potential way to optimize gas exchange is to increase surface area of alveoli by adding
____. PEEP
, What is Graham's gas law? Gases diffuse from a region of higher concentration (pressure) to
lower concentration (pressure) until equilibrium is reached.
A patient is at sea level (760 mmHg) and is on 30% O2 (FiO2 of 0.3). What is their partial
pressure of oxygen at this altitude? 228 (760 x 0.3)
Flicker Vertigo is primarily caused by what? Sunlight passing through the rotors (lower
spinning 5-20Hz - can cause vertigo and seizure activity)
For every decrease below sea level (going below water) of ___ feet is equal to additional ATM
33
(ex: 99 feet below water is 4 ATMs - using 1 ATM as your "zero")
Quick way to estimate patients PaO2 using FiO2? FiO2 x 5
Bedside calculation to estimate PaO2? (700 torr x FiO2) - 50
ex: (700 x .5) - 50. (*700 = estimated atmospheric pressure, .5 for FiO2 of 50%)
You compare your bedside calculation estimate of PaO2 to an actual ABG and notice a large
disparity, what physiological process is likely occuring? Shunt physiology (alveoli are
perfused with blood as normal, but ventilation/oxygenation fails to supply the perfused region)
What does the DEATH acronym stand for in regards to stressors of flight? Drugs, Exhaustion,
Alcohol, Tobacco, Hypoglycemia
A period of time from the onset of a decompression until a person is unable to effectively or
adequately perform duties due to an insufficient supply of oxygen. Time of useful
consciousness
What is atmospheric pressure at sea level? 760mmHg (or 760 torr)
T/F: Atmospheric pressure and barometric pressure are essentially the same thing, just using a
different unit of measure. True (think measuring same item in inches and then measuring it
in cm)
How many atmospheres (or ATMs) are at sea level? 1 atmosphere/ATM at sea level
What is barometric pressure? The combined weight of all atmospheric gases creating a force
upon the surface of the earth.
What is barometric pressure at sea level? 29.92Hg
According to Boyle's law, as altitude increases, barometric pressure ____, and gas in an
enclosed space ____ as long as temperature remains ____. decreases, expands, constant
T/F: As altitude increases, the measurement of Atmospheres (ATMs) also increases. False -
decreases
Quick math for calculating drop in ATMs until appx 5000/6000 feet altitude is that for every
____ increase in altitude, ATM goes down 5%. 1500 feet
What do the values of P1V1=P2V2 for Boyles law mean? P1 = starting ATM at the lowest
altitude
V1 = starting volume (ETT cuff, epigastrum, etc.)
P2 = highest ATM based on highest altitude
V2 = ending volume as impacted by highest altitude
*constant temperature*
,Due to Boyle's law, what type of physiologic process/pain may you experience on descent?
barotitus media - can't equalize ears (for test: only clinical issue that occurs on descent,
sinusitis ascent)
In barobariatrauma, according to boyles law, as altitude increases and atmospheric pressure
drops - the drop causes ____ to be displaced off of phospholipids and ____ narcosis can occur.
nitrogen, nitrogen
T/F: Barobariatrauma acts like a decompression sickness, such as a scuba diver who rapidly
ascends. True (would also be seen on ascent phase of flight)
Barobariatrauma is more common in what type of population of patients? morbidly obese
How is nitrogen narcosis from barobariatrauma treated? High flow O2 (preferably appx 15
minutes before flight if concerned this may present - morbidly obese, significant altitude
changes)
Barodentalgia (think boyles law) occurs in which phase of flight? ascent
According to Charles's law, if pressure is constant, what is the relationship of volume and
temperature? directly proportional (temp up = volume up, temp down = volume down)
(*think car tires*)
For every 1000' increase in altitude, how much will the temperature decrease? 2 degrees
celsius (if in meters - 150 meters ascent = 1 degree celsius temp decrease)
Which gas law states the following: At a given mass and constant volume of gas, the pressure
exerted on the sides of its container is directly proportional to its absolutely temperature.
Gay-Lusaac's law
,How many gases make up atmospheric air? 5 (nitrogen being the most, oxygen second)
What gas law states the sum of the partial pressure in a mixture of gases will equal the total
pressure? Dalton's law
A mix of Dalton's and Boyle's law concepts would conclude that as altitude ______,
atmospheric pressure decreases. Even though the pressure changes, the gas stays at the ____
proportions. Therefore, if increasing altitude, the partial pressure of oxygen (amount available
in atmosphere) will ___. increases, same, decrease
How do you calculate a partial pressure of oxygen? Oxygen in mmHg x oxygen concentration
Ex: 760mmHg (sea level) x 0.21 (normal O2 % in air) = 159.6mmHg (partial pressure aka
available amount of oxygen in atmosphere)
Normal paO2 on ABG? 80-100 (partial pressure of oxygen or amount of oxygen
measured/available in arterial blood)
What gas law states that the amount of gas dissolved in a solution is directly proportional to the
pressure of the gas on the surface of the solution? Henry's law
(think if you turn up FiO2 and there is more partial pressure of oxygen, more will be dissolved
Into the solution - or think pop can, CO2 under pressure in can escapes proportionately when
can is opened and pressure released)
When the alveoli are perfused with blood as normal, but ventilation/oxygenation fails to supply
the perfused region Shunting (may often be caused by some sort of blockage - PE, infectious
process/fluid)
One potential way to optimize gas exchange is to increase surface area of alveoli by adding
____. PEEP
, What is Graham's gas law? Gases diffuse from a region of higher concentration (pressure) to
lower concentration (pressure) until equilibrium is reached.
A patient is at sea level (760 mmHg) and is on 30% O2 (FiO2 of 0.3). What is their partial
pressure of oxygen at this altitude? 228 (760 x 0.3)
Flicker Vertigo is primarily caused by what? Sunlight passing through the rotors (lower
spinning 5-20Hz - can cause vertigo and seizure activity)
For every decrease below sea level (going below water) of ___ feet is equal to additional ATM
33
(ex: 99 feet below water is 4 ATMs - using 1 ATM as your "zero")
Quick way to estimate patients PaO2 using FiO2? FiO2 x 5
Bedside calculation to estimate PaO2? (700 torr x FiO2) - 50
ex: (700 x .5) - 50. (*700 = estimated atmospheric pressure, .5 for FiO2 of 50%)
You compare your bedside calculation estimate of PaO2 to an actual ABG and notice a large
disparity, what physiological process is likely occuring? Shunt physiology (alveoli are
perfused with blood as normal, but ventilation/oxygenation fails to supply the perfused region)
What does the DEATH acronym stand for in regards to stressors of flight? Drugs, Exhaustion,
Alcohol, Tobacco, Hypoglycemia
A period of time from the onset of a decompression until a person is unable to effectively or
adequately perform duties due to an insufficient supply of oxygen. Time of useful
consciousness
