Which is a feature of high altitude pulmonary edema-
**Core Concept**
High altitude pulmonary edema (HAPE) is a life-threatening condition that occurs when the body cannot adapt to the low oxygen levels at high altitudes, leading to fluid buildup in the lungs. This condition is characterized by non-cardiogenic pulmonary edema, where fluid accumulates in the lungs due to increased permeability of the pulmonary capillaries.
**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of HAPE, which involves the release of various vasoactive substances, including endothelin-1, that lead to pulmonary vasoconstriction and increased pulmonary artery pressure. This increased pressure causes fluid to leak from the pulmonary capillaries into the alveoli, resulting in HAPE. The correct answer is closely related to this mechanism.
**Why Each Wrong Option is Incorrect**
**Option A:** Not a feature of HAPE - HAPE is not primarily caused by a decrease in left atrial pressure.
**Option B:** Not a feature of HAPE - HAPE is not primarily caused by an increase in left ventricular ejection fraction.
**Option C:** Not a feature of HAPE - HAPE is not primarily caused by a decrease in oxygen saturation.
**Clinical Pearl / High-Yield Fact**
HAPE can be prevented by gradually ascending to high altitudes, allowing the body to adapt to the low oxygen levels. This is known as acclimatization.
**Correct Answer:** C. Non-cardiogenic pulmonary edema.