How should Brianna position Sarita when giving back blows?

Brianna should position Sarita bent forward at the waist with her upper body parallel to the ground when delivering back blows. This posture is essential because it allows gravity to assist in dislodging an obstruction from Sarita's airway. When the person is bent forward, any force applied, such as the back blows, has a greater chance of effectively displacing the object blocking the airway.

In this position, the back blows should be delivered between the shoulder blades, which targets the area where the obstruction might be dislodged. This technique is specifically designed to help expel foreign objects and can be crucial in emergencies involving choking.

The other positions do not facilitate the same effectiveness for this life-saving technique. For example, standing upright may not utilize gravity beneficially in the same way as bending forward does, and being on the ground or positioned in a chair does not provide the necessary tilt for effective back blows.