HYPERBARIC OXYGEN THERAPY (HBO) EXAM
WITH COMPLETE SOLUTIONS
1. Hyperbaric Oxygen Therapy (HBO) involves:
A. Breathing 21% oxygen at normal atmospheric pressure
B. Breathing 100% oxygen while under increased atmospheric pressure
C. Using a ventilator in a standard hospital room
D. Breathing 50% oxygen at sea level
Answer: B. Breathing 100% oxygen while under increased atmospheric pressure
Explanation: HBO increases the amount of oxygen dissolved in plasma by delivering 100%
oxygen under higher atmospheric pressure, improving tissue oxygenation.
2. Another term for an HBO treatment is:
A. Dive
B. Pressurization
C. Oxygen session
D. Hyperventilation
Answer: A. Dive
Explanation: In hyperbaric medicine, “dive” refers to the session in which the patient undergoes
HBO therapy, similar to descending underwater in terms of pressure dynamics.
3. A hyperbaric chamber is typically compressed with:
A. Pure oxygen
B. Air
C. Nitrogen
D. Helium
Answer: B. Air
Explanation: Multipurpose hyperbaric chambers are compressed with air to safely increase
ambient pressure, while oxygen is delivered to patients via mask or hood.
4. A treatment table is:
A. The table the patient lies on
B. A specific depth/time protocol used to treat a particular indication
C. The chart of patient vitals
D. A physical examination tool
Answer: B. A specific depth/time protocol used to treat a particular indication
Explanation: HBO treatment tables define the duration, pressure, and oxygen intervals for
treating conditions such as decompression sickness or radiation tissue injury.
5. ATA stands for:
A. Atmospheric total absorption
B. Absolute temperature adjustment
C. Atmosphere absolute
,D. Air tension approximation
Answer: C. Atmosphere absolute
Explanation: ATA is the unit of pressure used in hyperbaric medicine, representing total
pressure including ambient pressure and any added treatment pressure.
6. How is treatment depth measured in HBO?
A. Feet of water (fsw)
B. Meters above sea level
C. Inches of mercury
D. Cubic feet of chamber space
Answer: A. Feet of seawater (fsw)
Explanation: Treatment depth is often described as equivalent feet of seawater (fsw), where 1
ATA = 33 fsw.
7. Typical HBO treatment involves:
A. Going to 20 fsw and breathing room air for 1 hour
B. Going to 45 fsw and breathing 100% O₂ for 30 minutes x3 with breaks breathing ambient air
C. Immediate 100% O₂ at 6 ATA for 2 hours
D. Breathing 50% O₂ at 10 fsw for 15 minutes
Answer: B. Going to 45 fsw and breathing 100% O₂ for 30 minutes x3 with breaks breathing
ambient air
Explanation: Standard protocols include cycles of oxygen breathing at specific depths to
maximize oxygen delivery while minimizing toxicity.
8. Multiplace chambers are:
A. Compressed with oxygen and flammable
B. Compressed with air only and not flammable
C. Only for single patients
D. Not capable of ICU monitoring
Answer: B. Compressed with air only and not flammable
Explanation: Multiplace chambers can accommodate several patients safely, using air for
pressurization, while oxygen is delivered individually via mask or hood.
9. Mechanism of HBO: Direct Pressure Effect
A. Increases volume of bubbles
B. Decreases volume of bubbles (Boyle’s Law)
C. Dissolves nitrogen into tissue (Dalton’s Law)
D. Has no effect on bubbles
Answer: B. Decreases volume of bubbles (Boyle’s Law)
Explanation: Increased pressure reduces the size of gas bubbles in tissues, which is critical for
treating decompression sickness.
10. Mechanism of HBO: Hyperoxygenation
A. 2-3 fold increase in plasma oxygen
B. 10-15 fold increase in plasma oxygen, 1500-2200 mmHg O₂ content
C. Only improves breathing comfort
, D. Replaces hemoglobin function entirely
Answer: B. 10-15 fold increase in plasma oxygen, 1500-2200 mmHg O₂ content
Explanation: HBO greatly increases dissolved oxygen in plasma, enhancing diffusion to
hypoxic tissues independent of hemoglobin.
11. HBO adds:
A. More oxygen bound to hemoglobin
B. More oxygen dissolved in plasma
C. More nitrogen to tissues
D. Carbon dioxide removal
Answer: B. More oxygen dissolved in plasma
Explanation: While hemoglobin carries most oxygen under normal conditions, HBO adds
oxygen directly to plasma, improving tissue delivery even when circulation is compromised.
12. HBO secondary effects include:
A. Vasodilation and edema formation
B. Antimicrobial effect, toxin inhibition, bacteriostasis, enhanced antibiotic activity, improved
PMN function
C. Only increases oxygen tension
D. Decreases oxygen delivery to tissues
Answer: B. Antimicrobial effect, toxin inhibition, bacteriostasis, enhanced antibiotic activity,
improved PMN function
Explanation: HBO enhances immune function, inhibits bacterial growth, and potentiates some
antibiotics, aiding in wound healing and infection control.
13. Vasoconstriction during HBO leads to:
A. Increased edema
B. Decreased edema
C. No effect on fluid balance
D. Worsened hypoxia
Answer: B. Decreased edema
Explanation: HBO-induced vasoconstriction reduces fluid leakage into tissues, decreasing
swelling without compromising oxygen delivery due to hyperoxygenation.
14. Oxygen in multiplace chambers is delivered by:
A. Mask or hood
B. Chamber air only
C. IV infusion
D. Nasal cannula only
Answer: A. Mask or hood
Explanation: In multiplace chambers, oxygen is administered individually via mask or hood
while the chamber itself is pressurized with air for safety.
15. The chamber tender in a multiplace chamber has:
A. No direct access to patients
B. Direct access to patients inside the chamber
WITH COMPLETE SOLUTIONS
1. Hyperbaric Oxygen Therapy (HBO) involves:
A. Breathing 21% oxygen at normal atmospheric pressure
B. Breathing 100% oxygen while under increased atmospheric pressure
C. Using a ventilator in a standard hospital room
D. Breathing 50% oxygen at sea level
Answer: B. Breathing 100% oxygen while under increased atmospheric pressure
Explanation: HBO increases the amount of oxygen dissolved in plasma by delivering 100%
oxygen under higher atmospheric pressure, improving tissue oxygenation.
2. Another term for an HBO treatment is:
A. Dive
B. Pressurization
C. Oxygen session
D. Hyperventilation
Answer: A. Dive
Explanation: In hyperbaric medicine, “dive” refers to the session in which the patient undergoes
HBO therapy, similar to descending underwater in terms of pressure dynamics.
3. A hyperbaric chamber is typically compressed with:
A. Pure oxygen
B. Air
C. Nitrogen
D. Helium
Answer: B. Air
Explanation: Multipurpose hyperbaric chambers are compressed with air to safely increase
ambient pressure, while oxygen is delivered to patients via mask or hood.
4. A treatment table is:
A. The table the patient lies on
B. A specific depth/time protocol used to treat a particular indication
C. The chart of patient vitals
D. A physical examination tool
Answer: B. A specific depth/time protocol used to treat a particular indication
Explanation: HBO treatment tables define the duration, pressure, and oxygen intervals for
treating conditions such as decompression sickness or radiation tissue injury.
5. ATA stands for:
A. Atmospheric total absorption
B. Absolute temperature adjustment
C. Atmosphere absolute
,D. Air tension approximation
Answer: C. Atmosphere absolute
Explanation: ATA is the unit of pressure used in hyperbaric medicine, representing total
pressure including ambient pressure and any added treatment pressure.
6. How is treatment depth measured in HBO?
A. Feet of water (fsw)
B. Meters above sea level
C. Inches of mercury
D. Cubic feet of chamber space
Answer: A. Feet of seawater (fsw)
Explanation: Treatment depth is often described as equivalent feet of seawater (fsw), where 1
ATA = 33 fsw.
7. Typical HBO treatment involves:
A. Going to 20 fsw and breathing room air for 1 hour
B. Going to 45 fsw and breathing 100% O₂ for 30 minutes x3 with breaks breathing ambient air
C. Immediate 100% O₂ at 6 ATA for 2 hours
D. Breathing 50% O₂ at 10 fsw for 15 minutes
Answer: B. Going to 45 fsw and breathing 100% O₂ for 30 minutes x3 with breaks breathing
ambient air
Explanation: Standard protocols include cycles of oxygen breathing at specific depths to
maximize oxygen delivery while minimizing toxicity.
8. Multiplace chambers are:
A. Compressed with oxygen and flammable
B. Compressed with air only and not flammable
C. Only for single patients
D. Not capable of ICU monitoring
Answer: B. Compressed with air only and not flammable
Explanation: Multiplace chambers can accommodate several patients safely, using air for
pressurization, while oxygen is delivered individually via mask or hood.
9. Mechanism of HBO: Direct Pressure Effect
A. Increases volume of bubbles
B. Decreases volume of bubbles (Boyle’s Law)
C. Dissolves nitrogen into tissue (Dalton’s Law)
D. Has no effect on bubbles
Answer: B. Decreases volume of bubbles (Boyle’s Law)
Explanation: Increased pressure reduces the size of gas bubbles in tissues, which is critical for
treating decompression sickness.
10. Mechanism of HBO: Hyperoxygenation
A. 2-3 fold increase in plasma oxygen
B. 10-15 fold increase in plasma oxygen, 1500-2200 mmHg O₂ content
C. Only improves breathing comfort
, D. Replaces hemoglobin function entirely
Answer: B. 10-15 fold increase in plasma oxygen, 1500-2200 mmHg O₂ content
Explanation: HBO greatly increases dissolved oxygen in plasma, enhancing diffusion to
hypoxic tissues independent of hemoglobin.
11. HBO adds:
A. More oxygen bound to hemoglobin
B. More oxygen dissolved in plasma
C. More nitrogen to tissues
D. Carbon dioxide removal
Answer: B. More oxygen dissolved in plasma
Explanation: While hemoglobin carries most oxygen under normal conditions, HBO adds
oxygen directly to plasma, improving tissue delivery even when circulation is compromised.
12. HBO secondary effects include:
A. Vasodilation and edema formation
B. Antimicrobial effect, toxin inhibition, bacteriostasis, enhanced antibiotic activity, improved
PMN function
C. Only increases oxygen tension
D. Decreases oxygen delivery to tissues
Answer: B. Antimicrobial effect, toxin inhibition, bacteriostasis, enhanced antibiotic activity,
improved PMN function
Explanation: HBO enhances immune function, inhibits bacterial growth, and potentiates some
antibiotics, aiding in wound healing and infection control.
13. Vasoconstriction during HBO leads to:
A. Increased edema
B. Decreased edema
C. No effect on fluid balance
D. Worsened hypoxia
Answer: B. Decreased edema
Explanation: HBO-induced vasoconstriction reduces fluid leakage into tissues, decreasing
swelling without compromising oxygen delivery due to hyperoxygenation.
14. Oxygen in multiplace chambers is delivered by:
A. Mask or hood
B. Chamber air only
C. IV infusion
D. Nasal cannula only
Answer: A. Mask or hood
Explanation: In multiplace chambers, oxygen is administered individually via mask or hood
while the chamber itself is pressurized with air for safety.
15. The chamber tender in a multiplace chamber has:
A. No direct access to patients
B. Direct access to patients inside the chamber
