**Question:** A 2-day-old infant born at 32 weeks' gestation has had breathing difficulties since birth and is currently on a respirator and 100% oxygen. These difficulties occur because of which one of the following?

A. Hypoxia
B. Hyperoxia
C. Respiratory distress syndrome (RDS)
D. Pulmonary hypoplasia

**Correct Answer:** C. Respiratory distress syndrome (RDS)

**Core Concept:** Respiratory distress syndrome (RDS) is a condition affecting premature infants, particularly those born at a gestational age of less than 32 weeks or with a birth weight below 1500 grams. RDS occurs due to immaturity of the lungs, which results in decreased surfactant production and function. Surfactant is a substance that helps prevent alveoli from collapsing, allowing for efficient gas exchange in the lungs.

**Why the Correct Answer is Right:** In the case of a premature infant, the lungs may not have sufficient time to develop the necessary surfactant production and function. This leads to the alveoli collapsing, causing the infant to struggle with breathing due to insufficient oxygenation and excessive carbon dioxide retention. By using 100% oxygen, the problem worsens as oxygen can cause further damage to the immature lungs and exacerbate the respiratory distress.

**Why Other Options are Incorrect:**

A. Hypoxia: Hypoxia is a condition of insufficient oxygen supply to tissues, not a cause of respiratory distress in premature infants. Hypoxia could be a result of unmanaged respiratory distress, but it is not the primary cause in this scenario.

B. Hyperoxia: High oxygen concentrations, like 100%, can worsen RDS by damaging the immature lungs and impairing gas exchange.

D. Pulmonary hypoplasia: This refers to underdeveloped lungs, which is not the correct answer here. In the given scenario, the issue is with the immature lungs' surfactant production and function, not their overall size.

**Clinical Pearl:** Premature infants often require close monitoring and management of oxygen saturation, aiming for a target of around 85-95% oxygen saturation, depending on the gestational age and general condition of the infant.