CHT Hyperbaric Physics and Gas Laws

Question 1

Which gas law explains why a gas's volume decreases as pressure increases?

Accepted Answer

Boyle’s Law

Answer

Boyle’s Law states that for a fixed amount of gas at a constant temperature, the pressure and volume are inversely proportional. This means that as pressure increases, the volume of the gas decreases. This fundamental principle explains how gas volumes change with varying depths and pressures, which is critical in understanding physiological responses in hyperbaric environments.

Question 2

Which law is most directly associated with oxygen toxicity under pressure?

Accepted Answer

Henry’s Law

Answer

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. In hyperbaric oxygen therapy, increased ambient pressure leads to more oxygen dissolving into the blood plasma. While this increased dissolved oxygen is therapeutic, excessively high partial pressures can lead to oxygen toxicity, making Henry's Law crucial for understanding this risk.

Question 3

What happens to gas volume when a patient ascends rapidly from depth?

Accepted Answer

Volume increases

Answer

According to Boyle's Law, as external pressure decreases, the volume of a gas increases. When a patient ascends rapidly from depth, the surrounding pressure drops, causing any gas trapped in body cavities (like lungs, sinuses, or middle ear) to expand. This expansion can lead to barotrauma if not properly managed, highlighting the importance of controlled ascent.

Question 4

Which gas law supports the need to monitor partial pressures of oxygen during therapy?

Accepted Answer

Dalton’s Law

Answer

Dalton’s Law of Partial Pressures states that the total pressure exerted by a mixture of non-reacting gases is equal to the sum of the partial pressures of individual gases. In hyperbaric therapy, it is crucial to monitor the partial pressure of oxygen (PO2) to ensure therapeutic levels are achieved without causing toxicity. This law helps calculate the precise oxygen concentration needed at elevated pressures for safe and effective treatment.

Question 5

What is the typical pressure used in hyperbaric oxygen therapy?

Accepted Answer

2.0 to 2.5 ATA

Answer

The typical pressure range for most hyperbaric oxygen therapy (HBOT) treatments is between 2.0 and 2.5 atmospheres absolute (ATA). This range is considered optimal for achieving significant therapeutic benefits, such as dramatically increasing dissolved oxygen in the blood, while simultaneously minimizing the risks of oxygen toxicity and barotrauma. Adhering to this range ensures both efficacy and patient safety.

Certified Hyperbaric Technologist Test Practice Test

Certified Hyperbaric Technologist Test Practice Test

CHT Hyperbaric Physics and Gas Laws