What is the standard chest compression to rescue breaths ratio in adult CPR?

• A. 30:2
• B. 15:2
• C. 2:30
• D. 4:1

Answer: (A)

In adult CPR, the key idea is to maintain blood flow while providing enough breaths. The standard approach uses a cycle of 30 chest compressions, then 2 rescue breaths. This 30:2 ratio balances delivering circulatory support with oxygenating the blood, and it minimizes interruptions to chest compressions, which preserves perfusion to the heart and brain. If breaths are given too often or too slowly, perfusion can drop or ventilation can be insufficient, so the 30:2 pattern is the most effective compromise in adults.

Context: when two rescuers are involved in adult CPR, the same 30:2 cycle is typically used, though other ratios are taught for different ages or scenarios. The other options don’t fit adult practice: 15:2 is used for pediatric cases with two rescuers, not adults; 2:30 would imply far more breaths than compressions and disrupts perfusion; 4:1 is not a recognized standard in CPR.