The nurse is triaging several children as they present to the emergency room after a school bus accident. Which child requires the most immediate intervention by the nurse?

A 12-year-old reporting neck, arm, and lower back discomfort.

An 8-year-old with a full leg air splint for a possible broken tibia.

A 6-year-old with multiple superficial lacerations of all extremities.

An 11-year-old with a headache, nausea, and projectile vomiting.