CFRN EXAM QUESTIONS & ANSWERS
What is atmospheric pressure at sea level? - Answer -760mmHg (or 760 torr)
T/F: Atmospheric pressure and barometric pressure are essentially the same thing, just
using a different unit of measure. - Answer -True (think measuring same item in inches
and then measuring it in cm)
Quick math for calculating drop in ATMs until appx 5000/6000 feet altitude is that for
every ____ increase in altitude, ATM goes down 5%. - Answer -1500 feet
What do the values of P1V1=P2V2 for Boyles law mean? - Answer -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? - Answer -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. - Answer -nitrogen, nitrogen
T/F: Barobariatrauma acts like a decompression sickness, such as a scuba diver who
rapidly ascends. - Answer -True (would also be seen on ascent phase of flight)
Barobariatrauma is more common in what type of population of patients? - Answer -
morbidly obese
How many atmospheres (or ATMs) are at sea level? - Answer -1 atmosphere/ATM at
sea level
What is barometric pressure? - Answer -The combined weight of all atmospheric gases
creating a force upon the surface of the earth.
What is barometric pressure at sea level? - Answer -29.92Hg
According to Boyle's law, as altitude increases, barometric pressure ____, and gas in an
enclosed space ____ as long as temperature remains ____. - Answer -decreases,
expands, constant
,T/F: As altitude increases, the measurement of Atmospheres (ATMs) also increases. -
Answer -False - decreases
How is nitrogen narcosis from barobariatrauma treated? - Answer -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? - Answer -ascent
According to Charles's law, if pressure is constant, what is the relationship of volume
and temperature? - Answer -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? -
Answer -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. - Answer -Gay-Lusaac's law
How many gases make up atmospheric air? - Answer -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? - Answer -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 ___. - Answer -increases, same, decrease
How do you calculate a partial pressure of oxygen? - Answer -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? - Answer -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? - Answer -
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 - Answer -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 ____. - Answer -PEEP
What is Graham's gas law? - Answer -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? - Answer -228 (760 x 0.3)
Flicker Vertigo is primarily caused by what? - Answer -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 - Answer -33
(ex: 99 feet below water is 4 ATMs - using 1 ATM as your "zero")
Quick way to estimate patients PaO2 using FiO2? - Answer -FiO2 x 5
Bedside calculation to estimate PaO2? - Answer -(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? - Answer -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? - Answer -
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. -
Answer -Time of useful consciousness
T/F: In an explosive decompression above 40,000 feet time of useful consciousness will
be less than 10 seconds. - Answer -True (*test tip pick shortest amount of time
answer*)
T/F: The altimeter setting is your barometric pressure. - Answer -True
Desired FiO2 based on altitude formula? - Answer -(FiO2 x P1) / P2
, *P1 is current barometric pressure
*P2 is barometric pressure at highest flight altitude
(to maintain same level of oxygen therapy at a higher altitude)
PaO2 will decrease by ____________ mmHg for every _____________ feet increase in
altitude. - Answer -5/1000
If the atmospheric pressure at 18,000 ft. MSL is 380 torr, what would the partial
pressure of oxygen at that altitude? - Answer -79 torr (380 x 0.21)
A patient suffering from decompression sickness is an example of which gas law? -
Answer -Henry's
When administering high concentrations of oxygen to alleviate hypoxic hypoxia, you are
altering which component of which gas law? - Answer -Henry's (and the solubility of
oxygen diffusion into the solution - blood)
The inability of getting oxygen molecules down through airways, through alveolar
membrane, and onto a red blood cell, ultimately attaching to a hemoglobin molecule. -
Answer -Venous admixture or V/Q mismatch (Q stands for cardiac output/flow)
Patients with a VQ mismatch, at least early on, will often have what type of ABG? -
Answer -uncompensated respiratory alkalosis, PaO2 hypoxemia (patients tachypneic
leading to the respiratory alkalosis)
dead space ventilation (V/Q mismatch) - Answer -the volume of air inhaled that does
not take part in gas exchange because the alveoli are not perfused/poorly perfused
(the Q or flow/cardiac output portion of V/Q mismatch)
Acute exacerbation in COPD and Asthma leads to ventilatory failure by failure to ___,
therefore leading to air ___ and less volume being able to be moved throughout the
lungs. - Answer -exhale, trapping
T/F: Chronic COPD patients tend to be hypercarbic and hypoxemic on ABGs. - Answer
-True (think 50:50 club - PaCO2 >50, PaO2 <50)
ATP is a product of what type of metabolism? - Answer -Aerobic
For ATP production, the ____ nervous system stimulates ___ 2 receptors, which then
cause glycolosis to create more ATP. - Answer -sympathetic, beta
Lack of ___ or O2 causes an alteration of ATP production, and the byproduct is ____
acid. - Answer -glucose, lactic
T/F: Aerobic metabolism requires oxygen - Answer -True
What is atmospheric pressure at sea level? - Answer -760mmHg (or 760 torr)
T/F: Atmospheric pressure and barometric pressure are essentially the same thing, just
using a different unit of measure. - Answer -True (think measuring same item in inches
and then measuring it in cm)
Quick math for calculating drop in ATMs until appx 5000/6000 feet altitude is that for
every ____ increase in altitude, ATM goes down 5%. - Answer -1500 feet
What do the values of P1V1=P2V2 for Boyles law mean? - Answer -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? - Answer -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. - Answer -nitrogen, nitrogen
T/F: Barobariatrauma acts like a decompression sickness, such as a scuba diver who
rapidly ascends. - Answer -True (would also be seen on ascent phase of flight)
Barobariatrauma is more common in what type of population of patients? - Answer -
morbidly obese
How many atmospheres (or ATMs) are at sea level? - Answer -1 atmosphere/ATM at
sea level
What is barometric pressure? - Answer -The combined weight of all atmospheric gases
creating a force upon the surface of the earth.
What is barometric pressure at sea level? - Answer -29.92Hg
According to Boyle's law, as altitude increases, barometric pressure ____, and gas in an
enclosed space ____ as long as temperature remains ____. - Answer -decreases,
expands, constant
,T/F: As altitude increases, the measurement of Atmospheres (ATMs) also increases. -
Answer -False - decreases
How is nitrogen narcosis from barobariatrauma treated? - Answer -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? - Answer -ascent
According to Charles's law, if pressure is constant, what is the relationship of volume
and temperature? - Answer -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? -
Answer -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. - Answer -Gay-Lusaac's law
How many gases make up atmospheric air? - Answer -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? - Answer -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 ___. - Answer -increases, same, decrease
How do you calculate a partial pressure of oxygen? - Answer -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? - Answer -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? - Answer -
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 - Answer -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 ____. - Answer -PEEP
What is Graham's gas law? - Answer -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? - Answer -228 (760 x 0.3)
Flicker Vertigo is primarily caused by what? - Answer -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 - Answer -33
(ex: 99 feet below water is 4 ATMs - using 1 ATM as your "zero")
Quick way to estimate patients PaO2 using FiO2? - Answer -FiO2 x 5
Bedside calculation to estimate PaO2? - Answer -(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? - Answer -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? - Answer -
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. -
Answer -Time of useful consciousness
T/F: In an explosive decompression above 40,000 feet time of useful consciousness will
be less than 10 seconds. - Answer -True (*test tip pick shortest amount of time
answer*)
T/F: The altimeter setting is your barometric pressure. - Answer -True
Desired FiO2 based on altitude formula? - Answer -(FiO2 x P1) / P2
, *P1 is current barometric pressure
*P2 is barometric pressure at highest flight altitude
(to maintain same level of oxygen therapy at a higher altitude)
PaO2 will decrease by ____________ mmHg for every _____________ feet increase in
altitude. - Answer -5/1000
If the atmospheric pressure at 18,000 ft. MSL is 380 torr, what would the partial
pressure of oxygen at that altitude? - Answer -79 torr (380 x 0.21)
A patient suffering from decompression sickness is an example of which gas law? -
Answer -Henry's
When administering high concentrations of oxygen to alleviate hypoxic hypoxia, you are
altering which component of which gas law? - Answer -Henry's (and the solubility of
oxygen diffusion into the solution - blood)
The inability of getting oxygen molecules down through airways, through alveolar
membrane, and onto a red blood cell, ultimately attaching to a hemoglobin molecule. -
Answer -Venous admixture or V/Q mismatch (Q stands for cardiac output/flow)
Patients with a VQ mismatch, at least early on, will often have what type of ABG? -
Answer -uncompensated respiratory alkalosis, PaO2 hypoxemia (patients tachypneic
leading to the respiratory alkalosis)
dead space ventilation (V/Q mismatch) - Answer -the volume of air inhaled that does
not take part in gas exchange because the alveoli are not perfused/poorly perfused
(the Q or flow/cardiac output portion of V/Q mismatch)
Acute exacerbation in COPD and Asthma leads to ventilatory failure by failure to ___,
therefore leading to air ___ and less volume being able to be moved throughout the
lungs. - Answer -exhale, trapping
T/F: Chronic COPD patients tend to be hypercarbic and hypoxemic on ABGs. - Answer
-True (think 50:50 club - PaCO2 >50, PaO2 <50)
ATP is a product of what type of metabolism? - Answer -Aerobic
For ATP production, the ____ nervous system stimulates ___ 2 receptors, which then
cause glycolosis to create more ATP. - Answer -sympathetic, beta
Lack of ___ or O2 causes an alteration of ATP production, and the byproduct is ____
acid. - Answer -glucose, lactic
T/F: Aerobic metabolism requires oxygen - Answer -True
