During pediatric CPR, chest compressions should depress the chest to at least what fraction of the chest's anteroposterior diameter?

• A. At least one third
• B. At least one fourth
• C. At least one half
• D. Two inches

Answer: (A)

During pediatric CPR, the depth of chest compressions is guided by the size of the child’s chest. The best target is at least one third of the chest’s anteroposterior diameter. This proportional depth works across ages—from infants to older children—so the compressions are deep enough to generate blood flow but not so deep as to cause injury. Roughly, this depth translates to about 4 cm (around 1.5 inches) in smaller children and closer to 5 cm (about 2 inches) in larger children, depending on chest size.

The other options don’t fit the guideline because they aren’t scaled to the chest size. Compressing to a fixed depth like two inches isn’t universally correct for all pediatric sizes, and compressing to half the chest would be too deep and raise injury risk. Compressing only a quarter of the chest is typically too shallow to generate adequate perfusion.