Final answer:
Statement D regarding the use of nasopharyngeal airways in children is correct: They are rarely used in infants younger than 1 year. Nasopharyngeal airways are typically used in children aged 1 year and older to maintain an open airway and prevent obstruction.
Step-by-step explanation:
Based on the provided information, statement D is correct: Nasopharyngeal airways are rarely used in infants younger than 1 year. Nasopharyngeal airways are commonly used in children aged 1 year and older to maintain an open airway and facilitate ventilation. These flexible tubes are inserted through the nose and extend into the pharynx, helping to prevent airway obstruction. They are typically well tolerated by children with a gag reflex, making statement B incorrect. Nasopharyngeal airways are not the recommended adjunct for children with head trauma, making statement C incorrect. Blanching of the nares after insertion does not specifically indicate correct placement, making statement A incorrect.