Air Methods Critical Care Exam – 200 Practice
Questions & Answers with Rationales | Latest 2026
Exam Review | Flight Nursing & Transport Study
Guide
SECTION 1: FLIGHT PHYSIOLOGY & GAS LAWS (Questions 1–25)
1. According to Boyle's Law, what happens to the volume of a trapped gas as altitude
increases and atmospheric pressure decreases?
A. Volume decreases
B. Volume remains constant
C. Volume increases
D. Volume fluctuates randomly
Correct Answer: C
Rationale: Boyle's Law states that the volume of a gas is inversely proportional to pressure
at a constant temperature. As altitude increases, atmospheric pressure decreases, causing
trapped gas to expand. This explains the expansion of a pneumothorax, bowel gas, and air
in medical devices during ascent.
2. Which gas law explains why a pneumothorax expands during ascent?
A. Henry's Law
B. Boyle's Law
C. Charles's Law
D. Dalton's Law
Correct Answer: B
Rationale: Boyle's Law explains pneumothorax expansion during ascent: as atmospheric
pressure decreases, trapped intrapleural air volume increases. This is why patients with
untreated pneumothorax should not fly without appropriate intervention.
,3. According to Charles's Law, if an oxygen cylinder is filled to 2000 psi in a warm
hangar at 27°C (300 K) and moved to a cold flight ramp at -23°C (250 K) with volume
remaining constant, what happens to the internal pressure?
A. Pressure decreases proportionally to approximately 1666 psi
B. Pressure increases to 2400 psi
C. Pressure remains completely unchanged
D. Pressure drops instantly to zero
Correct Answer: A
Rationale: Charles's Law states that pressure is directly proportional to absolute
temperature at a constant volume. Cooling the gas decreases its kinetic energy and lowers
the internal pressure of the cylinder proportionally. The calculation is: P₂ = P₁ × (T₂ / T₁) =
2000 × () = 1666 psi.
4. Which gas law explains why hypoxia occurs more rapidly at altitude despite a
constant FiO₂ of 21%?
A. Boyle's Law
B. Dalton's Law
C. Charles's Law
D. Henry's Law
Correct Answer: B
Rationale: Dalton's Law states that the total pressure of a gas mixture equals the sum of
partial pressures of individual gases. As barometric pressure decreases with altitude, the
partial pressure of oxygen (PO₂) decreases proportionally, even though the fraction (21%)
remains constant. This drives the reduction in alveolar PO₂ and leads to hypoxia.
5. At an altitude of 18,000 feet, total barometric pressure is approximately 380 mmHg.
Regardless of altitude or total pressure, what remains relatively constant for the
partial pressure of water vapor inside the human lungs (PH₂O)?
A. It drops to zero
B. It remains constant at approximately 47 mmHg due to body temperature and full
humidification
C. It increases proportionally with barometric pressure
D. It equals the partial pressure of nitrogen
,Correct Answer: B
Rationale: Air entering the alveoli is fully humidified by the respiratory tract. At a normal
body temperature, the partial pressure of water vapor in the alveoli remains constant at
approximately 47 mmHg, regardless of altitude or total barometric pressure.
6. At a cabin altitude of 8,000 feet, the partial pressure of inspired oxygen (PiO₂) is
approximately:
A. 100 mm Hg
B. 120 mm Hg
C. 108 mm Hg
D. 80 mm Hg
Correct Answer: C
Rationale: PiO₂ = (Pb - 47) × FiO₂. At 8,000 ft, Pb ≈ 565 mm Hg. (565 - 47) × 0.21 = 108
mm Hg.
7. The pressure at sea level is 760 mm Hg. At 10,000 feet, it is approximately:
A. 650 mm Hg
B. 523 mm Hg
C. 450 mm Hg
D. 380 mm Hg
Correct Answer: B
Rationale: Pressure drops about 1 inch Hg (25 mm Hg) per 1,000 ft initially. At 10,000 ft, Pb
≈ 523 mm Hg.
8. Decompression sickness (DCS) is most likely to occur after a rapid ascent to
above:
A. 5,000 ft
B. 18,000 ft
C. 10,000 ft
D. 25,000 ft
Correct Answer: B
Rationale: DCS occurs when ambient pressure drops, causing nitrogen bubbles to form.
Significant risk begins above 18,000 ft without pressurization.
, 9. At altitude, a pulse oximeter may read falsely low because of:
A. Carboxyhemoglobin
B. Methemoglobin
C. Hypoperfusion and probe placement
D. Polycythemia
Correct Answer: C
Rationale: Cold, vibration, and peripheral vasoconstriction at altitude reduce signal quality.
Motion artifact from rotor wash also affects accuracy.
10. A patient with a pneumothorax during flight will most likely experience:
A. Expansion of the pneumothorax
B. Spontaneous resolution
C. Conversion to tension physiology only on descent
D. No change
Correct Answer: A
Rationale: Boyle's law: gas volume increases as pressure decreases. As altitude increases,
trapped pleural gas expands, worsening pneumothorax.
11. The maximum safe cabin altitude for an unpressurized patient with a closed head
injury is:
A. 10,000 ft
B. 5,000 ft
C. 8,000 ft
D. 3,000 ft
Correct Answer: B
Rationale: Hypoxia exacerbates cerebral edema. Maintain cabin altitude ≤ 5,000 ft or use
supplemental oxygen to keep SpO₂ > 90%.
12. Hypoxic hypoxia in flight is best treated by:
A. Increasing cabin altitude
B. Administering supplemental oxygen
C. Reducing FiO₂
D. Inducing hyperventilation
Questions & Answers with Rationales | Latest 2026
Exam Review | Flight Nursing & Transport Study
Guide
SECTION 1: FLIGHT PHYSIOLOGY & GAS LAWS (Questions 1–25)
1. According to Boyle's Law, what happens to the volume of a trapped gas as altitude
increases and atmospheric pressure decreases?
A. Volume decreases
B. Volume remains constant
C. Volume increases
D. Volume fluctuates randomly
Correct Answer: C
Rationale: Boyle's Law states that the volume of a gas is inversely proportional to pressure
at a constant temperature. As altitude increases, atmospheric pressure decreases, causing
trapped gas to expand. This explains the expansion of a pneumothorax, bowel gas, and air
in medical devices during ascent.
2. Which gas law explains why a pneumothorax expands during ascent?
A. Henry's Law
B. Boyle's Law
C. Charles's Law
D. Dalton's Law
Correct Answer: B
Rationale: Boyle's Law explains pneumothorax expansion during ascent: as atmospheric
pressure decreases, trapped intrapleural air volume increases. This is why patients with
untreated pneumothorax should not fly without appropriate intervention.
,3. According to Charles's Law, if an oxygen cylinder is filled to 2000 psi in a warm
hangar at 27°C (300 K) and moved to a cold flight ramp at -23°C (250 K) with volume
remaining constant, what happens to the internal pressure?
A. Pressure decreases proportionally to approximately 1666 psi
B. Pressure increases to 2400 psi
C. Pressure remains completely unchanged
D. Pressure drops instantly to zero
Correct Answer: A
Rationale: Charles's Law states that pressure is directly proportional to absolute
temperature at a constant volume. Cooling the gas decreases its kinetic energy and lowers
the internal pressure of the cylinder proportionally. The calculation is: P₂ = P₁ × (T₂ / T₁) =
2000 × () = 1666 psi.
4. Which gas law explains why hypoxia occurs more rapidly at altitude despite a
constant FiO₂ of 21%?
A. Boyle's Law
B. Dalton's Law
C. Charles's Law
D. Henry's Law
Correct Answer: B
Rationale: Dalton's Law states that the total pressure of a gas mixture equals the sum of
partial pressures of individual gases. As barometric pressure decreases with altitude, the
partial pressure of oxygen (PO₂) decreases proportionally, even though the fraction (21%)
remains constant. This drives the reduction in alveolar PO₂ and leads to hypoxia.
5. At an altitude of 18,000 feet, total barometric pressure is approximately 380 mmHg.
Regardless of altitude or total pressure, what remains relatively constant for the
partial pressure of water vapor inside the human lungs (PH₂O)?
A. It drops to zero
B. It remains constant at approximately 47 mmHg due to body temperature and full
humidification
C. It increases proportionally with barometric pressure
D. It equals the partial pressure of nitrogen
,Correct Answer: B
Rationale: Air entering the alveoli is fully humidified by the respiratory tract. At a normal
body temperature, the partial pressure of water vapor in the alveoli remains constant at
approximately 47 mmHg, regardless of altitude or total barometric pressure.
6. At a cabin altitude of 8,000 feet, the partial pressure of inspired oxygen (PiO₂) is
approximately:
A. 100 mm Hg
B. 120 mm Hg
C. 108 mm Hg
D. 80 mm Hg
Correct Answer: C
Rationale: PiO₂ = (Pb - 47) × FiO₂. At 8,000 ft, Pb ≈ 565 mm Hg. (565 - 47) × 0.21 = 108
mm Hg.
7. The pressure at sea level is 760 mm Hg. At 10,000 feet, it is approximately:
A. 650 mm Hg
B. 523 mm Hg
C. 450 mm Hg
D. 380 mm Hg
Correct Answer: B
Rationale: Pressure drops about 1 inch Hg (25 mm Hg) per 1,000 ft initially. At 10,000 ft, Pb
≈ 523 mm Hg.
8. Decompression sickness (DCS) is most likely to occur after a rapid ascent to
above:
A. 5,000 ft
B. 18,000 ft
C. 10,000 ft
D. 25,000 ft
Correct Answer: B
Rationale: DCS occurs when ambient pressure drops, causing nitrogen bubbles to form.
Significant risk begins above 18,000 ft without pressurization.
, 9. At altitude, a pulse oximeter may read falsely low because of:
A. Carboxyhemoglobin
B. Methemoglobin
C. Hypoperfusion and probe placement
D. Polycythemia
Correct Answer: C
Rationale: Cold, vibration, and peripheral vasoconstriction at altitude reduce signal quality.
Motion artifact from rotor wash also affects accuracy.
10. A patient with a pneumothorax during flight will most likely experience:
A. Expansion of the pneumothorax
B. Spontaneous resolution
C. Conversion to tension physiology only on descent
D. No change
Correct Answer: A
Rationale: Boyle's law: gas volume increases as pressure decreases. As altitude increases,
trapped pleural gas expands, worsening pneumothorax.
11. The maximum safe cabin altitude for an unpressurized patient with a closed head
injury is:
A. 10,000 ft
B. 5,000 ft
C. 8,000 ft
D. 3,000 ft
Correct Answer: B
Rationale: Hypoxia exacerbates cerebral edema. Maintain cabin altitude ≤ 5,000 ft or use
supplemental oxygen to keep SpO₂ > 90%.
12. Hypoxic hypoxia in flight is best treated by:
A. Increasing cabin altitude
B. Administering supplemental oxygen
C. Reducing FiO₂
D. Inducing hyperventilation
