Hypoxia is defined as a deficiency of what?

• A. Deficiency of oxygen in blood
• B. Buildup of carbon dioxide
• C. Blockage of airway causing chest tightness
• D. Loss of consciousness

Answer: (A)

Hypoxia means there isn’t enough oxygen reaching the body’s tissues. It happens when the oxygen content in the blood isn’t sufficient to meet tissue needs, which can occur if the breathing gas has too little oxygen or if oxygen delivery to the tissues is impaired. Buildup of carbon dioxide is hypercapnia, a different problem related to ventilation and gas exchange. An airway blockage with chest tightness is a mechanical issue that can lead to hypoxia but isn’t the definition itself. Loss of consciousness can be a severe consequence of oxygen deprivation, not the defining concept. In diving, preserving adequate arterial oxygen is essential to prevent tissue hypoxia and maintain safe performance.