Certified Hyperbaric Technologist Test CHT Hyperbaric Pharmacology 2 — Questions and Answers
Question 1: HBO therapy promotes angiogenesis in chronic wounds primarily through:
- Stimulating hypoxia-inducible factor (HIF) pathways during the post-treatment normoxic period (Correct answer)
- Direct mechanical pressure stretching capillary walls
- Nitrogen supersaturation promoting vessel growth
- Reducing inflammatory cytokines that inhibit vascular growth
Correct answer: Stimulating hypoxia-inducible factor (HIF) pathways during the post-treatment normoxic period
The oscillation between hyperoxia during treatment and relative hypoxia between sessions activates HIF-1α, driving VEGF-mediated angiogenesis.
Question 2: What is the mechanism by which HBO helps treat carbon monoxide poisoning?
- It accelerates dissociation of CO from hemoglobin by increasing dissolved oxygen (Correct answer)
- It converts carboxyhemoglobin directly to oxyhemoglobin through chamber pressure
- It neutralizes CO molecules in the bloodstream chemically
- It replaces red blood cells damaged by CO exposure
Correct answer: It accelerates dissociation of CO from hemoglobin by increasing dissolved oxygen
At 3 ATA with 100% O2, the half-life of CO-Hb is reduced from ~5 hours (room air) to ~20 minutes by competitively displacing CO.
Question 3: Hyperbaric oxygen enhances the killing of anaerobic bacteria by:
- Raising tissue oxygen levels toxic to obligate anaerobes that lack antioxidant enzymes (Correct answer)
- Physically crushing bacterial cell walls under pressure
- Reducing nutrient availability in the wound bed
- Activating neutrophil chemotaxis independent of oxygen levels
Correct answer: Raising tissue oxygen levels toxic to obligate anaerobes that lack antioxidant enzymes
Obligate anaerobes cannot neutralize reactive oxygen species generated under hyperoxia, making high pO2 directly bactericidal.
Question 4: Nitroglycerin patches worn during HBO present what risk?
- They may ignite or burn in the oxygen-enriched atmosphere (Correct answer)
- They absorb excess oxygen, reducing therapeutic benefit
- They interact with HBO to cause severe hypotension
- They are impermeable under pressure and deliver no medication
Correct answer: They may ignite or burn in the oxygen-enriched atmosphere
Transdermal nitroglycerin patches contain flammable materials and must be removed before HBO to prevent fire risk in the oxygen-enriched environment.
Question 5: Which statement about methylprednisolone and HBO therapy is most accurate?
- Corticosteroids may blunt the angiogenic and wound healing benefits of HBO (Correct answer)
- Corticosteroids are required to prevent oxygen toxicity during HBO
- Steroids increase the effectiveness of HBO at lower pressures
- No clinically relevant interaction exists between corticosteroids and HBO
Correct answer: Corticosteroids may blunt the angiogenic and wound healing benefits of HBO
Corticosteroids suppress inflammation and may impair the fibroblast proliferation and angiogenesis that HBO therapy aims to promote.
Question 6: Antineoplastic drug doxorubicin (Adriamycin) is a relative contraindication to HBO because:
- It acts as a free radical generator that synergizes with oxygen toxicity in the lungs (Correct answer)
- It sequesters in fatty tissue and is released dangerously under pressure
- It inactivates the enzymes that metabolize oxygen radicals
- It causes cardiac dysrhythmias specifically triggered by hyperoxia
Correct answer: It acts as a free radical generator that synergizes with oxygen toxicity in the lungs
Doxorubicin generates reactive oxygen species, and combined with hyperbaric oxygen, the cumulative free radical load can cause severe pulmonary toxicity.
Certified Hyperbaric Technologist Test CHT Hyperbaric Pharmacology 2
HBO therapy promotes angiogenesis in chronic wounds primarily through: