What is the primary mechanism of the postural drainage position?

• A. Uses gravity to move mucus from the lungs toward the throat for easier clearance
• B. Uses suction to remove mucus
• C. Uses pharmacologic thinning of mucus
• D. Uses heat to loosen secretions

Answer: (A)

Postural drainage relies on gravity to move mucus from the smaller airways toward the larger airways so it can be coughed up or swallowed. By positioning the body so the target lung segments are above the rest of the lungs, secretions naturally drain down toward the trachea. After holding the position, the patient may cough or huff to clear what has collected. This mechanism is about gravity, not suctioning devices, mucus-thinning medications, or applying heat. Postural drainage is often used with percussion or chest vibrations to loosen secretions, but gravity is the key driver of drainage.