What is the appropriate initial action for a nurse to take when an infant experiences a hypercyanotic spell due to Tetralogy of Fallot?

The initial action of placing the infant in a knee-chest position during a hypercyanotic spell due to Tetralogy of Fallot is appropriate because this position helps to increase systemic vascular resistance, which can improve blood flow to the lungs and decrease the degree of cyanosis. By flexing the knees towards the chest, the infant effectively reduces the right-to-left shunting of blood across the ventricular septal defect that occurs during these spells. This maneuver aids in directing more blood flow through the pulmonary artery, facilitating oxygenation and stabilizing the infant's condition.

In this context, prioritizing the knee-chest position is critical as it is a non-invasive intervention that can provide immediate support until further medical treatment, such as oxygen or medications, can be administered. Hence, understanding the physiological rationale behind positioning is essential for responding effectively during a hypercyanotic spell.