CPR will NOT be effective if the patient is:

• A. horizontal
• B. supine
• C. prone
• D. on a firm surface

Answer: (D)

Effective CPR relies on the patient being in the right position and on a solid base. When you compress the chest, you need a stable, flat surface so the force you apply goes into the chest and creates the necessary depth and full chest recoil between compressions. A firm, smooth surface provides that stability; a soft surface or a position that makes the chest hard to reach (like prone) makes it harder to achieve adequate depth and recoil, reducing effectiveness. So the setting that best supports effective CPR is the patient lying on their back (supine) on a firm surface. As a result, this option highlights the condition that enables proper chest compressions. In practice, you’d place the patient supine on a firm surface to maximize the chances of successful CPR.