Which two aviation-related types of hypoxia are commonly recognized?

Which two aviation-related types of hypoxia are commonly recognized?

• A. Hypemic hypoxia and hypoxic hypoxia
• B. Hypoxic hypoxia and histotoxic hypoxia
• C. Hypemic hypoxia and stagnant hypoxia
• D. Hypoxic hypoxia and ischemic hypoxia

Answer: (A)

In aviation, the most critical forms of hypoxia you’re taught to recognize are related to how oxygen gets to tissues: one is due to low oxygen partial pressure in the air we breathe (hypoxic hypoxia), and the other is due to a reduced ability of blood to carry oxygen (hypemic hypoxia). Hypoxic hypoxia happens when altitude lowers the amount of oxygen available in inspired air, so less oxygen dissolves in the blood and reaches tissues. Pilots feel symptoms like lightheadedness, headache, or impaired judgment as time at altitude increases. The fix is straightforward: descend to a lower altitude and supply supplemental oxygen to raise the amount of oxygen reaching the blood. Hypemic hypoxia occurs when something reduces the blood’s capacity to carry oxygen, even if the lungs are taking in air properly. Carbon monoxide poisoning from engine exhaust or certain kinds of anemia reduce how much oxygen blood can transport to tissues. Even with normal lung function, the delivered oxygen is insufficient. The remedy is to stop exposure to the reducing agent (e.g., CO source) and administer 100% oxygen, with descent if needed. Other forms, like histotoxic hypoxia (cells can’t use oxygen) or stagnant/ischemic hypoxia (blood flow is impaired), exist, but hypoxic and hypemic hypoxia are the two most commonly emphasized in aviation training.

In aviation, the most critical forms of hypoxia you’re taught to recognize are related to how oxygen gets to tissues: one is due to low oxygen partial pressure in the air we breathe (hypoxic hypoxia), and the other is due to a reduced ability of blood to carry oxygen (hypemic hypoxia).

Hypoxic hypoxia happens when altitude lowers the amount of oxygen available in inspired air, so less oxygen dissolves in the blood and reaches tissues. Pilots feel symptoms like lightheadedness, headache, or impaired judgment as time at altitude increases. The fix is straightforward: descend to a lower altitude and supply supplemental oxygen to raise the amount of oxygen reaching the blood.

Hypemic hypoxia occurs when something reduces the blood’s capacity to carry oxygen, even if the lungs are taking in air properly. Carbon monoxide poisoning from engine exhaust or certain kinds of anemia reduce how much oxygen blood can transport to tissues. Even with normal lung function, the delivered oxygen is insufficient. The remedy is to stop exposure to the reducing agent (e.g., CO source) and administer 100% oxygen, with descent if needed.

Other forms, like histotoxic hypoxia (cells can’t use oxygen) or stagnant/ischemic hypoxia (blood flow is impaired), exist, but hypoxic and hypemic hypoxia are the two most commonly emphasized in aviation training.