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?

The scenario describes a hypercyanotic spell, or tetralogy spell, in an infant with Tetralogy of Fallot. Managing this critical cardiac event requires applying knowledge of hemodynamic principles to increase systemic vascular resistance and improve pulmonary blood flow to alleviate severe hypoxia. Choice A rationale Morphine administration helps reduce infundibular spasms and decreases respiratory drive, which can lower oxygen demand. However, it is not the initial action because physical repositioning provides a more immediate hemodynamic shift to increase pulmonary perfusion. Choice B rationale Consoling the child is important to decrease anxiety and prevent further catecholamine release, which can worsen cardiac shunting. While beneficial for comfort, it does not address the physiological obstruction as rapidly as physical maneuvers do during spells. Choice C rationale Supplemental oxygen provides oxygenation to the tissues but does not correct the underlying right-to-left shunt caused by pulmonary stenosis. It is an adjunct therapy rather than the first priority intervention to reverse the anatomical shunting. Choice D rationale This maneuver increases systemic vascular resistance by compressing the femoral arteries. This forced pressure shift reduces the right-to-left shunt across the ventricular septal defect, forcing more blood into the lungs for oxygenation during acute spells.