In a preterm baby with respiratory distress syndrome which of the following lipid would be deficient
**Core Concept**
Respiratory distress syndrome (RDS) is a common condition in preterm babies caused by a deficiency of surfactant, a complex mixture of phospholipids and proteins that reduces surface tension in the lungs. The primary component of surfactant responsible for its surface tension-reducing properties is **dipalmitoylphosphatidylcholine (DPPC)**, a type of phospholipid.
**Why the Correct Answer is Right**
Surfactant deficiency in preterm babies leads to increased surface tension in the alveoli, causing them to collapse during exhalation and making it difficult to expand during inhalation. This results in the characteristic clinical features of RDS, including tachypnea, grunting, and retractions. The lack of surfactant is primarily due to a deficiency of phospholipids, particularly DPPC, which is essential for the proper function of surfactant.
**Why Each Wrong Option is Incorrect**
* **Option A:** Cholesterol is an important component of surfactant, but it is not the primary lipid responsible for its surface tension-reducing properties.
* **Option B:** Phosphatidylglycerol is another phospholipid present in surfactant, but it is not as crucial as DPPC for reducing surface tension.
* **Option D:** Triolein is a triglyceride and is not a component of surfactant.
**Clinical Pearl / High-Yield Fact**
Preterm babies with RDS often require surfactant replacement therapy, which involves administering exogenous surfactant to improve lung function and reduce the need for ventilatory support.
**Correct Answer:** C.