What is the recommended chest compression depth for infants during CPR?

• A. Approximately 1/4 the chest diameter
• B. Approximately 1/3 the chest diameter
• C. Approximately 1/3 the anterior-posterior chest diameter (about 4 cm)
• D. Approximately 1/2 the chest diameter

Answer: (C)

In infant CPR, the goal is to compress the chest enough to move blood without causing injury. The recommended depth is about one third of the chest’s front-to-back (anterior-posterior) diameter, which for an infant is roughly 4 cm (about 1.5 inches). This specific measurement matters because it reflects how much the chest should be shortened to propel blood effectively while preserving the chest’s delicate structures. Compressing about 1/3 of the AP diameter hits the balance between generating adequate perfusion and avoiding excessive force. If compressions are too shallow, blood flow is insufficient; if they’re too deep, the risk of injury increases. The one-third AP-diameter guideline is the standard for infants, and this depth applies whether you’re using two fingers (single rescuer) or two thumbs encircling the chest (two rescuers).