A 3-year-old child is diagnosed with congenital heart disease (CHD), specifically tetralogy of Fallot. The nurse is preparing to assess the child's cardiac status. Which of the following clinical manifestations is most commonly seen in children with tetralogy of Fallot?

A. Barking cough and inspiratory stridor, especially at night is incorrect because this is characteristic of croup, a respiratory condition, not tetralogy of Fallot. Tetralogy of Fallot primarily affects cardiac blood flow, not the upper airway. B. Bradycardia and hypotension following minor activity or mild stress is incorrect because children with tetralogy of Fallot typically develop tachycardia in response to hypoxia or stress, rather than bradycardia. Hypotension is not a hallmark sign unless there is shock or severe complications. C. Cyanosis that worsens during crying or feeding, often relieved by squatting is correct because children with tetralogy of Fallot have right-to-left shunting due to the combination of ventricular septal defect, pulmonary stenosis, overriding aorta, and right ventricular hypertrophy. This shunting reduces pulmonary blood flow, leading to cyanosis, which often becomes more pronounced during periods of increased oxygen demand, such as crying or feeding. Squatting increases systemic vascular resistance, temporarily reducing the shunt and improving oxygenation, which is known as a “Tet spell” relief maneuver. D. Peripheral edema and hepatomegaly during exertion or prolonged play is incorrect because these signs are more typical of heart failure rather than tetralogy of Fallot in a child without chronic severe heart failure. Tetralogy of Fallot presents primarily with cyanosis and hypoxic spells.