Chapter 1 - Flight Physiology / Avation Standards

Question 1

Barotitis Media typically occurs upon?

a. Ascent
b. Decent
c. Both
d. Neither

Answer 1

B:
Test Tip: barotitis media =>decent problems

Barotitis Media - related pain is the discomfort casued by pressure in the midde ear not being in equilibrium with the atmosphere. During the descent the atmospheric pressure pushing in on the tympanic membrane increase. If that same pressure cannot access the middle ear via the eustachian tubes an imbalance occurs and pain will result. It is uncommon for air to be unable to exacpe the middle ear via the eustaachian tubees so problems on the ascent are less common.

Question 2

Barobariatrauma is best prevented by?

a. positive pressure ventilation
b. pre-oxygenation
c. PEEP or CPAP usage
d. none of the above

Answer 2

B:
Test Tip: Barobariatrauma => pre oxygenate first

Barobariatrauma is caused by a large/sudden release of nitrogren from the adipose tissues of the body upon decompression. Normally the body would deal with this release of nitrogen by simply ‘blowing off’ the nitrogen via the pulmonary system just like carbon dioxide. However, in the very obese patient, the combination of excess nitrogren stores in addition to decreased functional residual capacity (FRC) and tidal volumes (Vt) lend to an inability to remove the nitrogen fast enough. By thoroughly pre-oxygenating, you replace the ntrogen in the FRC with oxygen therefore creating a large nitrogen partial pressure gradient. This increased gradien allows for rapid transfer of nitrogen from the plasma to the alveoli.

Question 3

Your portable O2 tank showed 1100psi on the pressure regulator during the shift change check at 0630hrs. THe tank was left exposed to the sun and two hours later shows a pressure of 1350psi. This is an example;

a. Boyles’s Law
b. Charles’s Law
c. Gay-Lussac’s Law
d. Graham’s Law

Answer 3

C:
Test Tip: “Gay-lussac’s is Charles’s gay brother”

Gay-Lussac’s Law is very similar to CHarles’s Law in that they both relate temperature to changes in pressure or volume respectively. In this case the volume is held constant (by the metal cylinder) and thus pressure is changed.

Question 4

Your patient is reportedly experiencing seasonal allergies in addition to the gigantic heart attack that he’s being transported for. Barosinusitis may occure during transport. You would expect the patient to complain of barosinusitis symptoms during;

a. ascent
b. descent
c. both
d. neither

Answer 4

A:

Barosinustis refers to air trapped in the sinuses. During ascent the falling atmospheric pressure can’t keep the air in the sinuses compressed, thus that gas attempts to expand causing pressure on the sinus wall and pain. As the patient descends, the increased atmospheric pressure will assist with controlling the barosinusitis.

Question 5

You are currently loading a patient at an airfield, which is at sea level. The barometric pressure is currently 760torr. Your patient is on supplemental O2 with an FIO2 of 0.3. The partial pressure of the oxygen as it enters the patient’s nasopharynx is;

a. 228 mmHg
b. 21%
c. 166 mmHg
d. impossible to determine from the information given

Answer 5

A:

Partial pressure is calculated by multiplying the given gas concentration by the total pressure present.
(This 760 mmHg x 0.3 = 228mmHg)

Question 6

During ascent you noted increased sporadic bubbling in a patient's chest tube drainage syste. This may demonstrate;
a, Boyles' Law
b. Henry's Law
c. Gay- Lussac's Law
d. Graham's Law

Answer 6

A:

The increased sporadic bubbling suggests air is excaping the patients chest. Based on the assumption the chest tube was placed for a pneumothorax, it would stand to reason that a residual pneumothorax is attempting to expand with the climb in altitude (Boyle’s Law) and thus some air is excaping via the chest tube. This sporadic bubbling could also infer an increased air leak in the chest or a chest drain system leak but these were not offered as answer choices.

Question 7

Boyles’ Law will affect all but which of the following:

a. a plaster cast
b. a foley catherter balloon
c. an endotracheal tube
d. an intra-aortic ballow pump balloon

Answer 7

B:
Test Tip: “Boyle’s balloon”

Boyle’s Law refers to gases attempting to expad as outside pressure is reduced. Gases in tissues will casue expansion of tissues under a cast to expand with ascent. This principle obviously applies to endotracheal tube cuffs as well as the balloon utilized with an intra aortic balloon pump. The foley balloon s filled with water, which will not expand for all intensive purposes, regardless of pressure changes encountered during transport. Any cast less then seven days old should be bi-valved and secured with an elastic bandage prior to transport. Monitoring of the distal extremity during transport is indicated with loosening of the elastic bandage should ciculation be compromised. Reporting of this cast bi-valving should occur at the receiving facility for appropriate replacement.

Question 8

You lifted from an airfield at 2100’ MSL, 98F with winds at 20kts with a heading of 110. Your helicopter has a climbed to 850’AGL with a rate of ascent of 300’/min. Your current altitude is;

a. assigned by the tower operator
b. 850’ MSL
c. 2950’ MSL
d. 2050’ MSL

Answer 8

C:

This question has an enormous amount of useles information or distracters. The term MSL and AGL must be understood to determin the appropriate answer.
MSL (Mean Sea Level) refers to the elevation above sea level.
ASL (Above Ground Level) refers to elevation above the ground directly below the AC
Thus beginning at an altitude of 2100ft MSL and climbing 850ft AGL would make your altitude (2100’ MSL + 850’ AGL) 2950 MSL

Question 9

The emergency locator transmitted frequency is;

a. 7700 Hz
b. 7500 Hz
c. 240 Hz
d. 121.5 Hz

Answer 9

D:

The emergency locator transmitter or “ELT” is a device attached to an aircraft which wll automatically send out a radio signal when triggered. Te device is located and designed to be automatically triggered by an inertial change of 4 G’s usch as an in “hard landing” or crash. This device can be triggered manually from the cockpit as well and via a toggle switch on the device itself.
ELT’s are commonly DOT organge or bright yellow in color, approximatley 10”x4”. They are rewuired to have an self-contained battery and antenna to enable physical seperation from the aircraft whil contiunuing to operate propertly.
NOTE: Civilian ELT’s historcically used 121.5Hz while the US military uses a Freq of 243Hz (243=121.5 x2). Newer ELT’s and satellite monitoring will be utilizing a 406 Hz Freq range wich may be mandated around 2009 wen dpecific satellites are the current system cease to function.

Question 10

You should anticipate a greater change in atmospheric pressure per altitude change when flying;

a. near the equator
b. over large bodies of water
c. near the north pole
d. during night time hours

Answer 10

C:

One must remember that the atmosphere is held to the Earth by gravity and all laws of physics apply including centripetal force. The Earth’s rotation causes the atmosphere to be “flung out” around the equator (aka - equatoral bulge) where the rotational speed is maximal versus the poles. As such the atmosphere is physically thicker at the equator (over land masses, water is subject to the same equatoral bulge). When changing altitude at the poles you will be rising through a greater overall percentage of the atmosphere at that point, thus larger changes in the atmospheric pressure will be experienced. Large bodies of water may affect humidity and thus density altitude. Night flying may also alter density altitude due to temperature changes.

Question 11

Charles’ Law states that as you increas the temperature of a gas you should anticipate;

a. a pressure increase
b. a volume increase
c. a solubility increase
d. a reduced gas weight

Answer 11

B:

Test Tip: “Charles’s = Centigrade”

Charles’s Law states that changes in tempature will casue a change in volume assuming pressure is constant. Thus as you heat the air in a balloon you would anticipate the gas to expand (assuming the balloon provides no significant resistance to such)

Question 12

Gay’Lussac’s Law most closely resembles;

a. Boyle’s Law
b. Dalton’s Law
c. Graham’s Law
d. Charles’s Law

Answer 12

D:
Test Tip: “Gay-lussac’s is Charles’s gay brother”

Gay-Lussac’s Law closely mirrors Charles’s Law. Gay-Lussac’s Law states that as you increase the temperature of a gas in a fixed volume container, the pressure must rise.

Charles’s Law states temperature increase results in a volume increase if constant pressure is maintained.
Gay-Lussac’s Law states temperature increase results in a pressure increase if constant volume is maintained.

Question 13

The release of gas exhibited when opening a carbonated drink is a clear demonstration of which gas law?

a. Boyle’s Law
b. Dalton’s Law
c. Henry’s Law
d. Graham’s Law

Answer 13

C:
Test Tip: Henry’s = Heineken

Henry’s Laws states, at a constant temperature, the amount of a given gas dissolved in a given type and volume of liquid is directely proportional to the partial pressure of that gas in an equilibrium with that liquid.
Once you open the bottle top, the pressure above the fluid immediately equalized with atomsphere becoming lower then the pressure of the gas dissolved in the beverage. As such, you begin to witness the gas escape the liquid in an attempt to reach equilibrium with the outside environment. The rate of this escape is governed by te partial pressure difference, the solubility of the gas in the liquid as well as the surface area which the atmosphere and liquid interface. Hence the narrow bottle neck style used in many carbonated beverages.

Question 14

Barodontalgia will likely be exacerbated by;

a. ascent
b. descent
c. turbulent flight
d. increased cabin pressurization

Answer 14

A:

Barodonalgia refers to gas trapped between dental appliances and teeth. This gas will attempt to expand upon ascent but due to dental appliance trapping, can only place pressure on the tooth underneath and subsequently any exposed nervous tissue. It has been reported that in extreme cases this can be significant enough

Question 15

As you ascend you would expect the pressure in your patient’s pneumatic anti-shock garment (PASG, aka - MAST) to;

a. increase
b. decrease
c. stay the same
d. fluctuate slightly with a descending trend in pressure

Answer 15

A:
As you ascend, the atmospheric pressure will drop allowing the gas tin the PASG to attempt to expand. Becasue the PASG is designed to maintain a maximum external girth (fixed container size), the expanding agas will translate to increased pressure inward and will be indicated by an elevated pressure gauge reading or “pulling” of the velcro attachments.

Question 16

“At a constant pressure, the volume of gas is directly proportional to the absolute temperature of the gas” describes;

a. Boyles’s Law
b. Dalton’s Law
c. Gay-Lussac’s Law
d. Charles’s Law

Answer 16

D
Test Tip: Charle’s Law = Centigrade

This is Charles’s Law

Question 17

For every 100 meters (1 meter = 3.3 feet) climb in altitude you can anticipate;

a. Decreasing concentration of oxygen of 1%
b. a temperature drop of 1’C
c. increasing concentration of nitrogren of 0.3%
d. a temperature increase as you get closer to the sun

Answer 17

B:
Test Tip: Climb 100 meter = drop 1’c

As you climb in altitude the temperature drops. Anticipate an 1’C for every 100 meter climb.
Concentration of oxygen does not change with altitude change. There is 21% oxygen at sea level, on top of Mount Everest and at 50,000 ft MSL. There are fewer molecules of all gases as you go up but 21% of those molecules are still oxygen.

D would be a good choice if we were asking about the Greek mythological character Icarus

Question 18

Graham’s Law is influenced more by;

a. velocity of gas flow
b. gas density
c. electrical gradient of the gase in question
d. physiologic properties of the gas in question

Answer 18

B:

Graham’s Law states the rate of diffusion of a gas is inversely proportional to the square root of its molecular wight.

Translation - dense gases diffuse slower than less dense gases through liquid.

The velocity of the gas, it’s electrical charge and physiologic properties all may effect your patient in some manner but none pertain to Graham’s Law.

Question 19

Dalton’s Law demonstrates that the concentration of oxygen at 40,000 MSL should be;

a. 12%
b. 16%
c. 18%
d. 21%

Answer 19

D:
Test Tip: “Dalton’s Gang”

Daltons’ Law states - the total pressure exerted by a gaseous mixture is equal to the sum of the partial pressures (“the entire gang”) of each individual component in a gas mixture.
As we go up in altitude we find that the precentage does not change, the atmosphere is uniform in its molecular distribution.

A sample of gas from 40,000’ MSL will have 21% oxygen, 78% nitrogen and 1% trace gases; identical to a sample at sea level.
However, because the atmospheric pressure at 40,000’ is substantially less we find that when calculating the partial presure of that oxygen (PO2) it’s substantially less at altitude vs sea level.

Using the calculation:
PO2 = Atmospheric pressure x FiO2

Question 20

Which of the following is true concerning air at high altitudes?

a. colder than air at lower altitude
b. more moist than air at lower altitude
c. higher concentration of nitrogen thn air at lower altitude
d. lower concentration of carbon diaxide than air at lower altitude

Answer 20

A:

As you ascend the air’s temperature will decrease and it will become dryer.
Concntration of the carious gases do not change, only their partial pressures.

Question 21

Which of the following is a stressor of flight;

a. barametric pressure changes
b. vibration
c. noise
d. all of the above

Answer 21

D:

All of these are considered stressors of flight along with decreased partial pressure of oxygen, thermal changes, dereased humidity, fatigue and G-forces.
KNOW THE STRESSORS OF FLIGHT!!

Question 22

Which of the following is not a actor influencing the stressors of flight?

a. alcohol
b. tobacco use
c. thermal changes
d. hypoglycemia

Answer 22

C

Thermal changes are considered an actual stressor of flight.

All the others exacerbate the stressors of flight. One way to approach this question is look at which answer is not like the others.
C is the only option that cannot be changed by the flight crewmember.

Question 23

On ‘standard atmosphere’ weights

a. 760 torr
b. 14.7 psi
c. 101.3 kPa
d. space

Answer 23

D

One ‘standard amosphere’ is the weight of the atmosphere at sea level at 59`F

Question 24

An altitude of 45,000’ MSL would be considered;

a. physiologic zone
b. space-equivalent zone
c. physicological deficient zone
d. space

Answer 24

C

Physiologic zone spans: sea level to 10K MSL
Physiologic deicient zone spans: 10K to 50K MSL
Space equivlent zone: 50K-250K MSL
Space: greater then 250K MSL

(In the US, anyone ascending more than 50nm or 303,805ft MSL is officially an “astronaut”)

Question 25

An othewise healthy individual exposed to the ambient environment at 20,000’ MSL would experance;

a. hypoxic hypoxia first
b. stagnant hypoxia first
c. hypemic hypoxia first
d. histotoxic hypoxia first

Answer 25

A

Hypoxic hypoxia - would result from exposure to an excesively low partial pressure of oxygen.

Stagnant hypoxia - requires the failure to move oxyhemorglobin to the needed areas or the body thus suggesting a cardiovascular impariment.

Hypermic hypoxia - would require a deficiency in oxygen carrying capacility such as anemia.

Histotoxic hypoxia - would require some form of exygen loading or unloading problem like cyanide poisoning.

Question 26

A patient with an H&H of 6 & 18 with an SaO2 of 95% will sufer primarily from _____________ if taken to 3500 ‘ MSL from sea level with O2 va a non-rebreather mask at 10Lpm

a. hypoxic hypoxia
b. stagnant hypxia
c. hypemic hypoxia
d. histotoxic hypoxia

Answer 26

C

Hypemic hypoxia refers to an inability to are oxygen that is available at the alveolar capillary interface. It is commonly praticed that an H&H of less then 8 & 24 should probably receive blood prior to being takent to altitude, with or without supplemental oxygen.

American College of Surgeons (ACS) suggests blood transfusions for 6 & 10

CaO2 = (1.34 X Hgb x SaO2) + (Pa02 x 0.003)

A drop in a Hgb from 15g/dL to 7.5g/dL decreases oxygen carrying capcitance (CaO2) by almost 50%.

Question 27

A pilot reports that he’s experiencing dizzines while ascending to a high altitdue in an unpressurized fixedwing aircraft. He would be considered in which stage of hypoxia?

a. indifferent stage
b. compensatory stage
c. disturbance stage
d. critical stage

Answer 27

C:

The disturbance stage follows the indifferent and compensatory stages.
It is typified by dizziness, sleepiness, tunnel vision and cyanosis. Without rpid recognition and correction of this, progression to significant disturbance and finally critical stage are eminent with an aircraft incident/accident very likely.

Question 28

You are transporting an infant with a congenital heart defect from New Orleans to Santa Fe. The altitude and weather indicate your barometric pressure will change from 760mmHg to 605mmHg. Your patient’s orders read that you must tricktly maintain the FiO2 at exactly 30%. Without an oxygen sensor/analyzer in use, you calculate the delivered FiO2 upon landing in Santa Fe should be;

a. 30%
b. 32%
c. 36%
d. 38%

Answer 28

D.
Test Tip:
The formula utilied for this calculation is:
(Pbi X FiO2 1) / Pb2 = FiO2 2

Pb1 is the barometric pressure at the starting point of transport
FiO2 1 is the O2 being delivered at he starting point
Pb2 is the barometric pressure at destination
FiO2 2 would you FiO2 at destination

Question 29

You are flying in a Learjet at 40,000’MSL when you experience an “explosive decompression’. You should anticipate your time of useful consciousness to be;

a. 30-60 sec
b. 60-90 sec
c. 120-150 sec
d. 3-5 sec

Answer 29

D
The term “explosive decompression” refers to any decompresion that takes les than 0.1 seond to occur. Sound wave creates the explosive bang. Will cause water vaport in the air to immediately condense to fog/smoke looking.

Test tip: pick the shortest time available

Question 30

You will be transporting a hemodynamically stable patient with a pneumocephalus. Wich of the following would be the best transport choice.

a. Ground CCT unit, transport time 2hrs 20min, change in altitude of 1,000’ as you cross the mountain pass from sending to receiving facility.
b. Rotor wing, transport time 1 hour, change in altitude of 6,000ft to safely cross mountain range that night.
c. Fixed wing (pressurized), transport time 1hr - 15min to closes airfield, 40 min by air 1hr from airfiedl to destination facility.
d. Horseback drawn sled, transport time 8 days, change in altitude dependnt upon how many times the patient falls of the sled.

Answer 30

A

The patient’s condition should alert you to the risks associated with changes in altitude. Climbing this patient to altitude will invoke Boyle’s Law to expand the bleed while causing increased ICP. While the transport time would be shorter, rotor-wing would be more hazardous. Fixed wing with careful attention to cabin pressure maybe adequately safe but total time is significantly longer in thei case.

Question 31

Commonly, healthy, unimpaired flight crewmembers wil begin to experience deterioration in night vision at;

a. 500’ ASL
b. 500’ MSL
c. 5,000’ AGL
d. 5,000’ MSL

Answer 31

D

The eye are especially susceptible to hypoxia. The otherwise healthy individual begins to experience vision changes due to hypoxia at approx. 5,000’ MSL.

Question 32

Night vision is primarily a function of the _________ which are located ___________ in the retina.

a. rods, center
b. rods, periphery
c. cones, center
d. cones, periphery

Answer 32

B

The rods, located along the periphery of the retina and are primarily responsible for night vision.
It is rhodopsin, a pigment in the rods that changes shape when absorbing light that provides us with night vision.
Scaning from the peripheral is recommended at night.
Cones are are designd for daytime lighting and because we are predominantly a diurnal creature they have developed in the central area o the retinas.