Hyperbaric Oxygen Therapy (HBO) Exam Questions
and Answers
1. The most common complication of HBO therapy is:
A. Seizures
B. Oxygen toxicity
C. Middle ear barotrauma
D. Pulmonary edema
Answer: C. Middle ear barotrauma
Explanation: Pressure changes stress the middle ear. Failure to equalize causes
barotrauma. It is usually mild and preventable. Education reduces incidence.
2. Hyperbaric oxygen enhances wound healing by:
A. Reducing pressure
B. Increasing angiogenesis
C. Lowering temperature
D. Decreasing metabolism
Answer: B. Increasing angiogenesis
Explanation: HBO stimulates new blood vessel formation. Increased oxygen supports
fibroblast activity. This improves collagen synthesis. Wound healing is accelerated.
3. Which law explains the increase in partial pressure of oxygen under pressure?
A. Boyle’s Law
B. Charles’ Law
C. Dalton’s Law
D. Graham’s Law
Answer: C. Dalton’s Law
Explanation: Dalton’s Law states total pressure equals the sum of partial pressures.
Increasing ambient pressure raises oxygen partial pressure. This enhances diffusion. It
underpins HBO effectiveness.
4. The primary goal of hyperbaric oxygen therapy is to:
A. Increase chamber pressure
B. Reduce pain
C. Improve tissue oxygenation
D. Eliminate nitrogen
Answer: C. Improve tissue oxygenation
Explanation: HBO dramatically increases oxygen availability. This supports ischemic and
infected tissues. Improved oxygenation enhances healing. All HBO benefits stem from
this mechanism.
5. Which law explains why oxygen dissolves into plasma under pressure?
A. Boyle’s Law
B. Henry’s Law
C. Dalton’s Law
D. Charles’ Law
, Answer: B. Henry’s Law
Explanation: Henry’s Law states that gas solubility increases as pressure increases. Under
hyperbaric conditions, oxygen dissolves directly into plasma. This allows oxygen
delivery independent of hemoglobin. This principle is essential to HBO therapy.
6. Which condition benefits from HBO due to improved angiogenesis?
A. Migraine
B. Radiation tissue injury
C. Hypertension
D. Asthma
Answer: B. Radiation tissue injury
Explanation: Radiation damages small blood vessels and reduces oxygen delivery. HBO
stimulates angiogenesis and capillary growth. This restores blood flow to injured tissue. It
improves wound healing and tissue viability.
7. The most common gas used to pressurize hyperbaric chambers is:
A. Oxygen
B. Nitrogen
C. Helium
D. Air
Answer: D. Air
Explanation: Chambers are pressurized with air to reduce fire risk. Oxygen concentration
is carefully controlled separately. Patients receive oxygen via masks or hoods. This
enhances safety during treatment.
8. A monoplace hyperbaric chamber typically exposes the patient to:
A. Compressed air
B. Heliox
C. 100% oxygen
D. Nitrox
Answer: C. 100% oxygen
Explanation: Monoplace chambers are oxygen-filled. The patient breathes oxygen
directly. This simplifies delivery systems. Strict fire safety protocols are required.
9. The most frequent adverse effect of HBO therapy is:
A. Seizures
B. Pulmonary edema
C. Middle ear barotrauma
D. Visual loss
Answer: C. Middle ear barotrauma
Explanation: Pressure changes affect the middle ear. Difficulty equalizing can cause pain
and injury. This is usually mild and preventable. Proper compression techniques reduce
risk.
10. Which technique helps prevent middle ear barotrauma during compression?
A. Hyperventilation
B. Swallowing
C. Breath holding
D. Rapid ascent
Answer: B. Swallowing
, Explanation: Swallowing opens the Eustachian tubes. This allows pressure equalization.
It reduces stress on the tympanic membrane. Patient education is key.
11. Oxygen toxicity affecting the lungs is primarily dependent on:
A. Pressure
B. Time
C. Depth
D. Temperature
Answer: B. Time
Explanation: Pulmonary oxygen toxicity develops with prolonged exposure. Symptoms
include cough and chest tightness. Pressure plays a lesser role than duration. Treatment
protocols limit exposure time.
12. Central nervous system oxygen toxicity is most likely to present as:
A. Cough
B. Seizure
C. Bradycardia
D. Hypotension
Answer: B. Seizure
Explanation: CNS oxygen toxicity can occur at high partial pressures. Seizures may
occur without warning. Air breaks help reduce this risk. Prompt management prevents
injury.
13. An air break during HBO therapy is used to:
A. Increase oxygen saturation
B. Shorten treatment time
C. Reduce oxygen toxicity
D. Increase nitrogen elimination
Answer: C. Reduce oxygen toxicity
Explanation: Air breaks decrease cumulative oxygen exposure. This allows antioxidant
systems to recover. They reduce the risk of CNS toxicity. Air breaks are standard in
many protocols.
14. Which patient is at highest risk for barotrauma during HBO?
A. One with cold or sinus congestion
B. Patient with anemia
C. Patient with hypertension
D. Patient with diabetes
Answer: A. One with cold or sinus congestion
Explanation: Congestion blocks normal pressure equalization. This increases stress on the
middle ear and sinuses. Patients are screened before therapy. Preventive strategies reduce
injury risk.
15. HBO therapy is contraindicated in:
A. Carbon monoxide poisoning
B. Pneumothorax
C. Diabetic foot ulcers
D. Radiation tissue injury
Answer: B. Pneumothorax
Explanation: Pneumothorax can worsen under pressure changes. Expanding air can
and Answers
1. The most common complication of HBO therapy is:
A. Seizures
B. Oxygen toxicity
C. Middle ear barotrauma
D. Pulmonary edema
Answer: C. Middle ear barotrauma
Explanation: Pressure changes stress the middle ear. Failure to equalize causes
barotrauma. It is usually mild and preventable. Education reduces incidence.
2. Hyperbaric oxygen enhances wound healing by:
A. Reducing pressure
B. Increasing angiogenesis
C. Lowering temperature
D. Decreasing metabolism
Answer: B. Increasing angiogenesis
Explanation: HBO stimulates new blood vessel formation. Increased oxygen supports
fibroblast activity. This improves collagen synthesis. Wound healing is accelerated.
3. Which law explains the increase in partial pressure of oxygen under pressure?
A. Boyle’s Law
B. Charles’ Law
C. Dalton’s Law
D. Graham’s Law
Answer: C. Dalton’s Law
Explanation: Dalton’s Law states total pressure equals the sum of partial pressures.
Increasing ambient pressure raises oxygen partial pressure. This enhances diffusion. It
underpins HBO effectiveness.
4. The primary goal of hyperbaric oxygen therapy is to:
A. Increase chamber pressure
B. Reduce pain
C. Improve tissue oxygenation
D. Eliminate nitrogen
Answer: C. Improve tissue oxygenation
Explanation: HBO dramatically increases oxygen availability. This supports ischemic and
infected tissues. Improved oxygenation enhances healing. All HBO benefits stem from
this mechanism.
5. Which law explains why oxygen dissolves into plasma under pressure?
A. Boyle’s Law
B. Henry’s Law
C. Dalton’s Law
D. Charles’ Law
, Answer: B. Henry’s Law
Explanation: Henry’s Law states that gas solubility increases as pressure increases. Under
hyperbaric conditions, oxygen dissolves directly into plasma. This allows oxygen
delivery independent of hemoglobin. This principle is essential to HBO therapy.
6. Which condition benefits from HBO due to improved angiogenesis?
A. Migraine
B. Radiation tissue injury
C. Hypertension
D. Asthma
Answer: B. Radiation tissue injury
Explanation: Radiation damages small blood vessels and reduces oxygen delivery. HBO
stimulates angiogenesis and capillary growth. This restores blood flow to injured tissue. It
improves wound healing and tissue viability.
7. The most common gas used to pressurize hyperbaric chambers is:
A. Oxygen
B. Nitrogen
C. Helium
D. Air
Answer: D. Air
Explanation: Chambers are pressurized with air to reduce fire risk. Oxygen concentration
is carefully controlled separately. Patients receive oxygen via masks or hoods. This
enhances safety during treatment.
8. A monoplace hyperbaric chamber typically exposes the patient to:
A. Compressed air
B. Heliox
C. 100% oxygen
D. Nitrox
Answer: C. 100% oxygen
Explanation: Monoplace chambers are oxygen-filled. The patient breathes oxygen
directly. This simplifies delivery systems. Strict fire safety protocols are required.
9. The most frequent adverse effect of HBO therapy is:
A. Seizures
B. Pulmonary edema
C. Middle ear barotrauma
D. Visual loss
Answer: C. Middle ear barotrauma
Explanation: Pressure changes affect the middle ear. Difficulty equalizing can cause pain
and injury. This is usually mild and preventable. Proper compression techniques reduce
risk.
10. Which technique helps prevent middle ear barotrauma during compression?
A. Hyperventilation
B. Swallowing
C. Breath holding
D. Rapid ascent
Answer: B. Swallowing
, Explanation: Swallowing opens the Eustachian tubes. This allows pressure equalization.
It reduces stress on the tympanic membrane. Patient education is key.
11. Oxygen toxicity affecting the lungs is primarily dependent on:
A. Pressure
B. Time
C. Depth
D. Temperature
Answer: B. Time
Explanation: Pulmonary oxygen toxicity develops with prolonged exposure. Symptoms
include cough and chest tightness. Pressure plays a lesser role than duration. Treatment
protocols limit exposure time.
12. Central nervous system oxygen toxicity is most likely to present as:
A. Cough
B. Seizure
C. Bradycardia
D. Hypotension
Answer: B. Seizure
Explanation: CNS oxygen toxicity can occur at high partial pressures. Seizures may
occur without warning. Air breaks help reduce this risk. Prompt management prevents
injury.
13. An air break during HBO therapy is used to:
A. Increase oxygen saturation
B. Shorten treatment time
C. Reduce oxygen toxicity
D. Increase nitrogen elimination
Answer: C. Reduce oxygen toxicity
Explanation: Air breaks decrease cumulative oxygen exposure. This allows antioxidant
systems to recover. They reduce the risk of CNS toxicity. Air breaks are standard in
many protocols.
14. Which patient is at highest risk for barotrauma during HBO?
A. One with cold or sinus congestion
B. Patient with anemia
C. Patient with hypertension
D. Patient with diabetes
Answer: A. One with cold or sinus congestion
Explanation: Congestion blocks normal pressure equalization. This increases stress on the
middle ear and sinuses. Patients are screened before therapy. Preventive strategies reduce
injury risk.
15. HBO therapy is contraindicated in:
A. Carbon monoxide poisoning
B. Pneumothorax
C. Diabetic foot ulcers
D. Radiation tissue injury
Answer: B. Pneumothorax
Explanation: Pneumothorax can worsen under pressure changes. Expanding air can
