HYPERBARIC OXYGEN THERAPY (HBO) EXAM
QUESTIONS WITH ANSWERS AND EXPLANATIONS
1. 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, reducing oxygen delivery. HBO
stimulates angiogenesis and capillary growth, restoring blood flow. This improves wound
healing and tissue viability.
2. 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 is delivered
separately through masks or hoods. Controlling oxygen concentration enhances safety.
3. 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 filled with oxygen. The patient breathes oxygen directly.
Strict fire safety protocols are required.
4. 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. Pain and injury occur if equalization is
difficult. Proper compression techniques reduce risk.
5. 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.
Education reduces tympanic stress.
6. 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. Treatment protocols limit exposure duration.
7. 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 risk.
8. 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 reduce cumulative oxygen exposure. Antioxidant systems recover
during breaks. This reduces CNS toxicity risk.
9. 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 pressure equalization. Stress on the middle ear and sinuses
increases. Screening prevents injury.
10. HBO therapy is contraindicated in:
A. Carbon monoxide poisoning
B. Pneumothorax
C. Diabetic foot ulcers
D. Radiation tissue injury
,Answer: B. Pneumothorax
Explanation: Untreated pneumothorax can expand and collapse the lung. HBO is dangerous
until corrected. Safety requires screening before therapy.
11. Which effect does HBO have on bacteria?
A. Reduces bacterial growth of anaerobes
B. Increases bacterial growth
C. Has no effect
D. Causes viral replication
Answer: A. Reduces bacterial growth of anaerobes
Explanation: Anaerobic bacteria thrive in low oxygen. HBO increases tissue oxygen, inhibiting
anaerobic growth. This is critical in gas gangrene treatment.
12. Which of the following is a monoplace chamber characteristic?
A. Patient lies in a pressurized air chamber
B. Patient sits in a multiplace chamber with others
C. Chamber is filled with 100% oxygen
D. Patient breathes room air
Answer: C. Chamber is filled with 100% oxygen
Explanation: Monoplace chambers are for single patients. Oxygen fills the chamber entirely.
Continuous monitoring ensures safety.
13. How does HBO help treat decompression sickness?
A. Removes nitrogen bubbles from tissues
B. Reduces heart rate
C. Increases carbon dioxide retention
D. Lowers blood pressure
Answer: A. Removes nitrogen bubbles from tissues
Explanation: Rapid ascent forms nitrogen bubbles in blood. HBO increases ambient pressure,
shrinking bubbles. Oxygen also supports tissue recovery.
14. Which condition commonly treated with HBO involves chronic non-healing wounds?
A. Stroke
B. Diabetic foot ulcers
C. Migraine
D. Asthma
Answer: B. Diabetic foot ulcers
Explanation: Chronic ulcers have poor oxygen delivery. HBO increases oxygen to ischemic
tissue, promoting healing. Infection risk is reduced, improving limb salvage.
15. HBO therapy is indicated for carbon monoxide poisoning because:
A. It removes nitrogen
B. It binds hemoglobin faster than carbon monoxide
C. It reduces tissue oxygen demand
D. It increases blood pressure
Answer: B. It binds hemoglobin faster than carbon monoxide
, Explanation: Carbon monoxide binds hemoglobin tightly. HBO accelerates oxygen
displacement. Tissue oxygenation is restored, preventing hypoxic injury.
16. Which type of tissue benefits most from HBO in ischemic injuries?
A. Fat tissue
B. Muscle tissue
C. Bone tissue
D. Cartilage
Answer: B. Muscle tissue
Explanation: Muscle is highly metabolic and oxygen-dependent. Ischemia limits oxygen
delivery. HBO enhances recovery and repair in compromised tissue.
17. Which of the following is a late complication of HBO therapy?
A. Pulmonary edema
B. Cataracts
C. Ear barotrauma
D. Seizures
Answer: B. Cataracts
Explanation: Prolonged oxygen exposure oxidizes the lens. Cataracts may develop over time.
Risk is cumulative; regular eye exams are recommended.
18. Which gas law explains why HBO reduces nitrogen bubbles in decompression sickness?
A. Boyle’s Law
B. Charles’s Law
C. Henry’s Law
D. Dalton’s Law
Answer: A. Boyle’s Law
Explanation: Boyle’s Law states gas volume decreases as pressure increases. HBO reduces
nitrogen bubble size, aiding reabsorption. This prevents tissue damage.
19. The most common symptom of mild oxygen toxicity is:
A. Cough
B. Nausea
C. Visual changes
D. Seizures
Answer: C. Visual changes
Explanation: Early CNS oxygen toxicity may cause blurred vision or tunnel vision. Monitoring
prevents progression. Air breaks reduce risk.
20. Which factor increases the risk of CNS oxygen toxicity during HBO?
A. Low pressure
B. Long duration at high oxygen pressure
C. Breathing room air
D. Cold temperature
Answer: B. Long duration at high oxygen pressure
QUESTIONS WITH ANSWERS AND EXPLANATIONS
1. 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, reducing oxygen delivery. HBO
stimulates angiogenesis and capillary growth, restoring blood flow. This improves wound
healing and tissue viability.
2. 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 is delivered
separately through masks or hoods. Controlling oxygen concentration enhances safety.
3. 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 filled with oxygen. The patient breathes oxygen directly.
Strict fire safety protocols are required.
4. 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. Pain and injury occur if equalization is
difficult. Proper compression techniques reduce risk.
5. 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.
Education reduces tympanic stress.
6. 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. Treatment protocols limit exposure duration.
7. 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 risk.
8. 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 reduce cumulative oxygen exposure. Antioxidant systems recover
during breaks. This reduces CNS toxicity risk.
9. 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 pressure equalization. Stress on the middle ear and sinuses
increases. Screening prevents injury.
10. HBO therapy is contraindicated in:
A. Carbon monoxide poisoning
B. Pneumothorax
C. Diabetic foot ulcers
D. Radiation tissue injury
,Answer: B. Pneumothorax
Explanation: Untreated pneumothorax can expand and collapse the lung. HBO is dangerous
until corrected. Safety requires screening before therapy.
11. Which effect does HBO have on bacteria?
A. Reduces bacterial growth of anaerobes
B. Increases bacterial growth
C. Has no effect
D. Causes viral replication
Answer: A. Reduces bacterial growth of anaerobes
Explanation: Anaerobic bacteria thrive in low oxygen. HBO increases tissue oxygen, inhibiting
anaerobic growth. This is critical in gas gangrene treatment.
12. Which of the following is a monoplace chamber characteristic?
A. Patient lies in a pressurized air chamber
B. Patient sits in a multiplace chamber with others
C. Chamber is filled with 100% oxygen
D. Patient breathes room air
Answer: C. Chamber is filled with 100% oxygen
Explanation: Monoplace chambers are for single patients. Oxygen fills the chamber entirely.
Continuous monitoring ensures safety.
13. How does HBO help treat decompression sickness?
A. Removes nitrogen bubbles from tissues
B. Reduces heart rate
C. Increases carbon dioxide retention
D. Lowers blood pressure
Answer: A. Removes nitrogen bubbles from tissues
Explanation: Rapid ascent forms nitrogen bubbles in blood. HBO increases ambient pressure,
shrinking bubbles. Oxygen also supports tissue recovery.
14. Which condition commonly treated with HBO involves chronic non-healing wounds?
A. Stroke
B. Diabetic foot ulcers
C. Migraine
D. Asthma
Answer: B. Diabetic foot ulcers
Explanation: Chronic ulcers have poor oxygen delivery. HBO increases oxygen to ischemic
tissue, promoting healing. Infection risk is reduced, improving limb salvage.
15. HBO therapy is indicated for carbon monoxide poisoning because:
A. It removes nitrogen
B. It binds hemoglobin faster than carbon monoxide
C. It reduces tissue oxygen demand
D. It increases blood pressure
Answer: B. It binds hemoglobin faster than carbon monoxide
, Explanation: Carbon monoxide binds hemoglobin tightly. HBO accelerates oxygen
displacement. Tissue oxygenation is restored, preventing hypoxic injury.
16. Which type of tissue benefits most from HBO in ischemic injuries?
A. Fat tissue
B. Muscle tissue
C. Bone tissue
D. Cartilage
Answer: B. Muscle tissue
Explanation: Muscle is highly metabolic and oxygen-dependent. Ischemia limits oxygen
delivery. HBO enhances recovery and repair in compromised tissue.
17. Which of the following is a late complication of HBO therapy?
A. Pulmonary edema
B. Cataracts
C. Ear barotrauma
D. Seizures
Answer: B. Cataracts
Explanation: Prolonged oxygen exposure oxidizes the lens. Cataracts may develop over time.
Risk is cumulative; regular eye exams are recommended.
18. Which gas law explains why HBO reduces nitrogen bubbles in decompression sickness?
A. Boyle’s Law
B. Charles’s Law
C. Henry’s Law
D. Dalton’s Law
Answer: A. Boyle’s Law
Explanation: Boyle’s Law states gas volume decreases as pressure increases. HBO reduces
nitrogen bubble size, aiding reabsorption. This prevents tissue damage.
19. The most common symptom of mild oxygen toxicity is:
A. Cough
B. Nausea
C. Visual changes
D. Seizures
Answer: C. Visual changes
Explanation: Early CNS oxygen toxicity may cause blurred vision or tunnel vision. Monitoring
prevents progression. Air breaks reduce risk.
20. Which factor increases the risk of CNS oxygen toxicity during HBO?
A. Low pressure
B. Long duration at high oxygen pressure
C. Breathing room air
D. Cold temperature
Answer: B. Long duration at high oxygen pressure
