Hyperbaric Physics Fundamentals Flashcards
6 cards from real Certified Hyperbaric Technologist Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Hyperbaric Physics Fundamentals flashcards as text
What does Boyle's Law state and how does it apply to hyperbaric medicine?
Answer: At constant temperature, gas volume is inversely proportional to pressure — explains barotrauma and why air spaces compress under pressure
Boyle's Law (PV=k) states that gas volume decreases proportionally as pressure increases at constant temperature, explaining why middle ear spaces, sinuses, and lungs compress during descent and expand during ascent.
What does Henry's Law state and why is it important in HBO therapy?
Answer: Gas dissolved in a liquid is proportional to the partial pressure of that gas — explains how HBO increases dissolved oxygen in blood
Henry's Law states that the amount of gas dissolved in a liquid is directly proportional to the partial pressure of that gas above the liquid, explaining how breathing oxygen at elevated pressures dramatically increases dissolved oxygen in plasma.
What is Dalton's Law of Partial Pressures?
Answer: The total pressure of a gas mixture equals the sum of the partial pressures of each component gas
Dalton's Law states that each gas in a mixture exerts pressure independently, and the total pressure equals the sum of all partial pressures. At 3 ATA breathing 100% O2, the PO2 is 3.0 ATA × 1.0 = 3.0 ATA (2,280 mmHg).
What is oxygen toxicity and what are its two forms?
Answer: Harmful effects from excessive oxygen: CNS toxicity (seizures) at high pressures and pulmonary toxicity from prolonged exposure
CNS oxygen toxicity (Paul Bert effect) occurs at high partial pressures (typically >2.0 ATA PO2) causing seizures, while pulmonary toxicity (Lorrain Smith effect) results from prolonged breathing of elevated oxygen, causing lung inflammation.
How does gauge pressure differ from absolute pressure in hyperbaric medicine?
Answer: Gauge measures pressure above atmospheric; absolute includes atmospheric pressure (gauge + 1 ATA at sea level)
Gauge pressure (psig) measures pressure above atmospheric baseline, while absolute pressure (psia or ATA) includes atmospheric pressure. At sea level: 1 ATA absolute = 0 psig. At 2 ATA: gauge is 14.7 psig.
What is the significance of 1.3 ATA in hyperbaric medicine?
Answer: It is the minimum pressure defined by UHMS for hyperbaric oxygen therapy — below this is not considered HBO
The Undersea and Hyperbaric Medical Society defines HBO as breathing 100% oxygen at a pressure of at least 1.3 ATA. Treatment below this threshold is not considered true hyperbaric oxygen therapy.
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