Hyperbaric Medicine Principles & Physiology Flashcards

What is the Fick principle as applied to oxygen delivery in hyperbaric physiology?

Answer: Oxygen consumption equals cardiac output multiplied by the arteriovenous oxygen difference

The Fick principle states that VO2 = CO × (CaO2 − CvO2), linking oxygen consumption to cardiac output and the arteriovenous oxygen content difference.

A diver ascending too rapidly may develop pulmonary barotrauma. Which of the following is NOT a recognized manifestation of this injury?

Answer: Decompression sickness Type I joint pain

Pulmonary barotrauma causes AGE, pneumothorax, mediastinal emphysema, and subcutaneous emphysema; Type I joint pain DCS is caused by bubble formation in tissues, not lung rupture.

Reactive oxygen species (ROS) generated during HBO2 therapy serve a beneficial role in wound healing by:

Answer: Directly killing bacteria and stimulating fibroblast proliferation

At controlled levels, HBO2-generated ROS act as signaling molecules that enhance bactericidal activity of neutrophils and stimulate fibroblast proliferation and collagen synthesis.

In hyperbaric physiology, what does the term 'super-saturation' refer to in relation to decompression sickness risk?

Answer: Tissue inert gas tension exceeding ambient pressure, allowing bubble formation

Supersaturation occurs when inert gas tension in tissues exceeds the surrounding ambient pressure after ascent, creating conditions for bubble nucleation and decompression sickness.

What is the physiological rationale for air breaks during hyperbaric oxygen therapy?

Answer: To allow washout of reactive oxygen species and reduce CNS oxygen toxicity risk

Air breaks interrupt continuous oxygen exposure, allowing tissue antioxidant defenses to recover and reducing cumulative risk of CNS oxygen toxicity seizures.

Which parameter best predicts whether a diving injury requires recompression therapy rather than surface-level oxygen first aid alone?

Answer: Presence of neurological symptoms or failure to resolve with normobaric oxygen

Neurological symptoms or lack of improvement with 100% surface oxygen are the primary indicators for recompression therapy, regardless of depth or dive profile alone.

Dalton's Law of partial pressures is fundamental to hyperbaric medicine because it explains:

Answer: How each gas in a mixture contributes independently to total pressure and physiological effects

Dalton's Law states that total pressure equals the sum of partial pressures of each component gas; this explains how individual gas toxicities and physiological effects scale with depth.