Which is not seen in ARDS?
**Core Concept**
Acute Respiratory Distress Syndrome (ARDS) is a life-threatening condition characterized by rapid onset of non-cardiogenic pulmonary edema, leading to hypoxemic respiratory failure. It occurs due to an imbalance between the influx of fluid into the lungs and the ability of the lymphatic system to clear it.
**Why the Correct Answer is Right**
ARDS is defined by the Berlin definition, which includes four key criteria: acute onset, non-cardiogenic pulmonary edema, bilateral opacities on chest imaging, and impaired oxygenation. One of the key features of ARDS is the absence of left atrial hypertension, which distinguishes it from cardiogenic pulmonary edema. The correct answer to this question is the option that is not a characteristic of ARDS.
**Why Each Wrong Option is Incorrect**
**Option A:**
This is actually a characteristic of ARDS, as the condition is defined by the presence of bilateral opacities on chest imaging.
**Option B:**
This is also a characteristic of ARDS, as the condition is associated with impaired oxygenation due to the non-cardiogenic pulmonary edema.
**Option C:**
This is not a characteristic of ARDS, as the condition is not typically associated with pleural effusions. Pleural effusions are more commonly seen in other conditions such as heart failure, pneumonia, or malignancy.
**Clinical Pearl / High-Yield Fact**
In the context of ARDS, it is essential to remember that the Berlin definition is the most widely accepted classification system, and it helps to distinguish ARDS from other conditions that may present with similar symptoms.
**Correct Answer:** C.