What does not contribute to effective back blow techniques for an infant?

Positioning the infant face up does not contribute to effective back blow techniques because the procedure requires the infant to be in a face-down position. This orientation ensures that gravity can aid in dislodging an obstruction from the airway, allowing for better efficacy when administering back blows. It is crucial for the infant's head to be lower than their body, as this angle facilitates the movement of secretions or foreign objects out of the airway.

Additionally, using the heel of the hand is essential for delivering the appropriate force without causing injury, while having a firm surface for support helps stabilize the infant during the procedure. Thus, face positioning plays a critical role in making back blows effective, which is why face-up positioning is not appropriate for this emergency technique.