**Core Concept**
The scenario describes a neonate with congenital diaphragmatic hernia (CDH) and respiratory distress, who has undergone bag-mask ventilation followed by endotracheal intubation. CDH is a congenital anomaly characterized by a defect in the diaphragm, allowing abdominal contents to herniate into the thoracic cavity, leading to pulmonary hypoplasia and mediastinal shift.

**Why the Correct Answer is Right**
In this scenario, the maximal cardiac impulse shifted to the right side after intubation, indicating a possible esophageal intubation or malposition of the endotracheal tube (ETT). A correctly placed ETT in a neonate with CDH should not cause a further shift of the cardiac impulse. The next step is to remove the ETT and reattempt intubation to ensure proper placement and prevent further complications such as hypoxia, gastric aspiration, or worsening respiratory distress.

**Why Each Wrong Option is Incorrect**

**Option A:** Confirming the position of the ETT by x-ray chest is not the immediate next step, as it may delay critical care and could lead to further complications due to prolonged bag-mask ventilation.
**Option C:** Insertion of a nasogastric tube is not relevant in this scenario, as the primary concern is the correct placement of the ETT.
**Option D:** Chest x-ray is an essential diagnostic tool in CDH, but it is not the immediate next step in management after suspecting ETT malposition.

**Clinical Pearl / High-Yield Fact**
In neonates with CDH, it is crucial to maintain a high index of suspicion for esophageal intubation, as it can lead to severe complications. A correctly placed ETT should be confirmed by clinical signs such as equal breath sounds bilaterally, symmetric chest rise, and absence of gastric inflation.

**✓ Correct Answer: B. Remove tube & Reattempt intubation**