In adults, how deep should external chest compressions depress the sternum during CPR?

• A. 1 - 2 inches
• B. 2 - 3 inches
• C. 3 - 4 inches
• D. 4 - 5 inches

Answer: (A)

The main concept is how deep external chest compressions should depress the sternum in an adult during CPR. The best answer is about one to two inches of compression with each push. This depth roughly corresponds to one-third of the chest’s thickness in the average adult, which provides enough forward blood flow to circulate without causing excessive injury. Compressing deeper than this increases the risk of rib fractures, sternal injury, or damage to underlying organs, and it doesn’t necessarily improve perfusion beyond the safe, effective depth. If compressions are too shallow, they won’t generate adequate cardiac output. While performing CPR, maintain a steady rate of about 100–120 compressions per minute and allow full chest recoil between pushes, minimizing interruptions to maximize effectiveness.