A nurse is providing care to an infant who has tetralogy of Fallot. The infant's caregiver reports increased irritability and a bluish discoloration of the infant's oral mucous membranes. Which of the following interventions is the nurse's priority?

Rationale: A. Consoling the child is incorrect because soothing the infant does not address the underlying physiologic cause of the acute cyanosis and irritability. These symptoms indicate a hypercyanotic episode (tet spell), a medical emergency caused by a sudden increase in right-to-left shunting in tetralogy of Fallot. Simply consoling the infant will not improve oxygenation or reduce the degree of cardiac shunting. B. Administering morphine is an appropriate intervention during a tet spell because morphine helps reduce infundibular spasm, decreases agitation, and lowers oxygen demand. However, while beneficial, it is not the immediate priority since positioning the child provides more rapid physiologic improvement and can be implemented instantly without a medication order or delay. C. Providing supplemental oxygen is helpful because oxygen acts as a pulmonary vasodilator and can improve oxygen saturation during a tet spell. However, oxygen alone does not correct the primary problem, which is the acute increase in right-to-left shunting due to decreased pulmonary blood flow. While supplemental oxygen should be applied promptly, it is not the first priority intervention. D. Placing the child in a knee-to-chest position is correct because this is the priority and most immediate life-saving intervention during a hypercyanotic episode. The knee-to-chest position increases systemic vascular resistance, which decreases the right-to-left shunt, allowing more blood to flow into the pulmonary circulation. This results in improved oxygenation, reduced cyanosis, and stabilization of the infant's condition. It is simple, requires no equipment, and directly targets the cause of the episode, making it the first and most urgent intervention.