Hyperbaric Medicine Exam Questions – Actual
Questions with Correct Answers and Explanations
1. Henshaw is known for:
A. Inventing the recompression chamber
B. Using compressed air for digestion and respiration
C. Designing the diving dress
D. Calculating partial pressure of oxygen
Answer: B. Using compressed air for digestion and respiration
Explanation: Henshaw was one of the earliest inventors to explore the use of
compressed air for medical purposes, including aiding digestion and respiration. His
work laid the foundation for hyperbaric medicine.
2. John Lethbridge is famous for:
A. Installing the first recompression chamber
B. Designing the diving dress in 1715
C. Discovering Boyle’s Law
D. Studying oxygen toxicity
Answer: B. Designing the diving dress in 1715
Explanation: Lethbridge designed a practical diving suit that allowed divers to work
underwater while staying dry. This early innovation influenced later diving technology.
3. The first recompression chamber was installed in:
A. 1700
B. 1715
C. 1893
D. 1920
Answer: C. 1893 for caisson workers
Explanation: Recompression chambers were initially installed to treat workers exposed
to high-pressure conditions during caisson construction. These chambers helped prevent
decompression sickness.
4. Caisson disease is also known as:
A. Oxygen toxicity
B. Hyperbaric sickness
C. The Bends or DCS
D. Barotrauma
Answer: C. The Bends or DCS
Explanation: Caisson disease occurs when nitrogen bubbles form in tissues during rapid
decompression. Symptoms include joint pain, dizziness, and neurological problems.
5. Pressure in diving results from:
A. Gas solubility
B. Water and atmospheric weight
, C. Oxygen toxicity
D. Alveolar gas calculation
Answer: B. Water and atmospheric weight
Explanation: The pressure a diver experiences is the sum of water pressure from the
depth and atmospheric pressure. This pressure affects gas behavior in the body.
6. One cubic foot of seawater weighs:
A. 50 lbs
B. 64 lbs
C. 72 lbs
D. 100 lbs
Answer: B. 64 lbs
Explanation: Seawater is denser than freshwater, with each cubic foot weighing
approximately 64 pounds. This is important for calculating buoyancy and pressure.
7. Boyle's Law states:
A. Gas volume varies inversely with pressure
B. Gas pressure varies directly with temperature
C. Gas dissolves in liquid based on partial pressure
D. Whole gas sum equals parts
Answer: A. Gas volume varies inversely with pressure
Explanation: As pressure increases, gas volume decreases proportionally. Divers must
understand this law to prevent barotrauma during descent and ascent.
8. Dalton's Law states:
A. Gas volume varies with temperature
B. Total gas pressure equals the sum of partial pressures
C. Pressure change in fluid is transmitted undiminished
D. Gas dissolves in liquid based on partial pressure
Answer: B. Total gas pressure equals the sum of partial pressures
Explanation: Dalton’s Law allows calculation of individual gas pressures in mixtures.
This is critical for safe diving gas planning.
9. Partial Pressure of Oxygen (PPO2) at sea level is:
A. 0.1
B. 0.21
C. 1.0
D. 2.0
Answer: B. 0.21
Explanation: Air is approximately 21% oxygen, so PPO2 at sea level is 0.21 atm. PPO2
increases with depth, which can lead to oxygen toxicity if uncontrolled.
10. Henry's Law explains:
A. Gas volume varies inversely with pressure
B. Gas dissolves in liquid based on partial pressure
C. Gas pressure varies directly with temperature
D. Objects appear closer in water
Answer: B. Gas dissolves in liquid based on partial pressure
Explanation: Higher pressure increases gas solubility in fluids. Divers need to ascend
slowly to avoid nitrogen bubble formation.
, 11. HBOT (Hyperbaric Oxygen Therapy) works by:
A. Reducing oxygen in plasma
B. Super-saturating plasma with oxygen
C. Decreasing partial pressure of oxygen
D. Increasing CO2 in blood
Answer: B. Super-saturating plasma with oxygen
Explanation: HBOT raises the amount of oxygen dissolved in plasma, enhancing tissue
oxygenation. This promotes healing and combats hypoxia and infections.
12. Gay-Lussac’s Law states:
A. Gas volume varies inversely with pressure
B. Gas volume varies with temperature at constant pressure
C. Gas pressure varies directly with temperature
D. Pressure change in fluid is transmitted undiminished
Answer: C. Gas pressure varies directly with temperature
Explanation: In a sealed chamber, increasing temperature raises gas pressure. This
principle is critical for hyperbaric chamber safety.
13. Charles’ Law states:
A. Gas volume varies with temperature at constant pressure
B. Gas dissolves in liquid based on partial pressure
C. Gas pressure varies inversely with temperature
D. Pressure change in fluid is transmitted undiminished
Answer: A. Gas volume varies with temperature at constant pressure
Explanation: Gas expands when heated at constant pressure. This is important when
managing chamber conditions in HBOT.
14. Pascal’s Law explains:
A. Gas volume varies inversely with pressure
B. Pressure change in a fluid is transmitted undiminished
C. Gas dissolves in liquid based on partial pressure
D. Gas pressure varies directly with temperature
Answer: B. Pressure change in a fluid is transmitted undiminished
Explanation: This law allows uniform pressure distribution in hyperbaric chambers,
ensuring consistent treatment for patients.
15. Refraction in water causes objects to appear:
A. Further and smaller
B. Closer and larger
C. Unchanged
D. Distorted randomly
Answer: B. Closer and larger
Explanation: Light bends entering water, creating an optical illusion. Divers must
account for this when judging distances underwater.
16. Speed of sound in water is approximately:
A. 1125 feet per second
B. 4700 feet per second
C. 3400 feet per second
D. 5280 feet per second
Answer: B. 4700 feet per second
Questions with Correct Answers and Explanations
1. Henshaw is known for:
A. Inventing the recompression chamber
B. Using compressed air for digestion and respiration
C. Designing the diving dress
D. Calculating partial pressure of oxygen
Answer: B. Using compressed air for digestion and respiration
Explanation: Henshaw was one of the earliest inventors to explore the use of
compressed air for medical purposes, including aiding digestion and respiration. His
work laid the foundation for hyperbaric medicine.
2. John Lethbridge is famous for:
A. Installing the first recompression chamber
B. Designing the diving dress in 1715
C. Discovering Boyle’s Law
D. Studying oxygen toxicity
Answer: B. Designing the diving dress in 1715
Explanation: Lethbridge designed a practical diving suit that allowed divers to work
underwater while staying dry. This early innovation influenced later diving technology.
3. The first recompression chamber was installed in:
A. 1700
B. 1715
C. 1893
D. 1920
Answer: C. 1893 for caisson workers
Explanation: Recompression chambers were initially installed to treat workers exposed
to high-pressure conditions during caisson construction. These chambers helped prevent
decompression sickness.
4. Caisson disease is also known as:
A. Oxygen toxicity
B. Hyperbaric sickness
C. The Bends or DCS
D. Barotrauma
Answer: C. The Bends or DCS
Explanation: Caisson disease occurs when nitrogen bubbles form in tissues during rapid
decompression. Symptoms include joint pain, dizziness, and neurological problems.
5. Pressure in diving results from:
A. Gas solubility
B. Water and atmospheric weight
, C. Oxygen toxicity
D. Alveolar gas calculation
Answer: B. Water and atmospheric weight
Explanation: The pressure a diver experiences is the sum of water pressure from the
depth and atmospheric pressure. This pressure affects gas behavior in the body.
6. One cubic foot of seawater weighs:
A. 50 lbs
B. 64 lbs
C. 72 lbs
D. 100 lbs
Answer: B. 64 lbs
Explanation: Seawater is denser than freshwater, with each cubic foot weighing
approximately 64 pounds. This is important for calculating buoyancy and pressure.
7. Boyle's Law states:
A. Gas volume varies inversely with pressure
B. Gas pressure varies directly with temperature
C. Gas dissolves in liquid based on partial pressure
D. Whole gas sum equals parts
Answer: A. Gas volume varies inversely with pressure
Explanation: As pressure increases, gas volume decreases proportionally. Divers must
understand this law to prevent barotrauma during descent and ascent.
8. Dalton's Law states:
A. Gas volume varies with temperature
B. Total gas pressure equals the sum of partial pressures
C. Pressure change in fluid is transmitted undiminished
D. Gas dissolves in liquid based on partial pressure
Answer: B. Total gas pressure equals the sum of partial pressures
Explanation: Dalton’s Law allows calculation of individual gas pressures in mixtures.
This is critical for safe diving gas planning.
9. Partial Pressure of Oxygen (PPO2) at sea level is:
A. 0.1
B. 0.21
C. 1.0
D. 2.0
Answer: B. 0.21
Explanation: Air is approximately 21% oxygen, so PPO2 at sea level is 0.21 atm. PPO2
increases with depth, which can lead to oxygen toxicity if uncontrolled.
10. Henry's Law explains:
A. Gas volume varies inversely with pressure
B. Gas dissolves in liquid based on partial pressure
C. Gas pressure varies directly with temperature
D. Objects appear closer in water
Answer: B. Gas dissolves in liquid based on partial pressure
Explanation: Higher pressure increases gas solubility in fluids. Divers need to ascend
slowly to avoid nitrogen bubble formation.
, 11. HBOT (Hyperbaric Oxygen Therapy) works by:
A. Reducing oxygen in plasma
B. Super-saturating plasma with oxygen
C. Decreasing partial pressure of oxygen
D. Increasing CO2 in blood
Answer: B. Super-saturating plasma with oxygen
Explanation: HBOT raises the amount of oxygen dissolved in plasma, enhancing tissue
oxygenation. This promotes healing and combats hypoxia and infections.
12. Gay-Lussac’s Law states:
A. Gas volume varies inversely with pressure
B. Gas volume varies with temperature at constant pressure
C. Gas pressure varies directly with temperature
D. Pressure change in fluid is transmitted undiminished
Answer: C. Gas pressure varies directly with temperature
Explanation: In a sealed chamber, increasing temperature raises gas pressure. This
principle is critical for hyperbaric chamber safety.
13. Charles’ Law states:
A. Gas volume varies with temperature at constant pressure
B. Gas dissolves in liquid based on partial pressure
C. Gas pressure varies inversely with temperature
D. Pressure change in fluid is transmitted undiminished
Answer: A. Gas volume varies with temperature at constant pressure
Explanation: Gas expands when heated at constant pressure. This is important when
managing chamber conditions in HBOT.
14. Pascal’s Law explains:
A. Gas volume varies inversely with pressure
B. Pressure change in a fluid is transmitted undiminished
C. Gas dissolves in liquid based on partial pressure
D. Gas pressure varies directly with temperature
Answer: B. Pressure change in a fluid is transmitted undiminished
Explanation: This law allows uniform pressure distribution in hyperbaric chambers,
ensuring consistent treatment for patients.
15. Refraction in water causes objects to appear:
A. Further and smaller
B. Closer and larger
C. Unchanged
D. Distorted randomly
Answer: B. Closer and larger
Explanation: Light bends entering water, creating an optical illusion. Divers must
account for this when judging distances underwater.
16. Speed of sound in water is approximately:
A. 1125 feet per second
B. 4700 feet per second
C. 3400 feet per second
D. 5280 feet per second
Answer: B. 4700 feet per second
