During CPR in Basic Life Support, what is the chest compression to ventilation ratio for adults?

• A. 15 compressions to 2 ventilations.
• B. 30 compressions to 2 ventilations.
• C. 2 compressions to 30 ventilations.
• D. 5 compressions to 1 ventilation.

Answer: (B)

The key idea is delivering chest compressions efficiently to keep blood flowing, while providing a small, controlled amount of oxygen via breaths. For adults in Basic Life Support, the standard pattern pairs 30 chest compressions with 2 rescue breaths. This 30:2 ratio maximizes perfusion by keeping interruptions to compressions brief, while still delivering oxygen to the lungs and bloodstream. Aim for a compression rate of about 100–120 per minute and a depth of roughly 5 cm (2 inches) with complete chest recoil between compressions. If two rescuers are present, they can switch roles to keep compressions steady and breaths delivered promptly, but the overall cycle remains 30 compressions followed by 2 breaths. Other ratios are used in different contexts (like pediatric CPR), but for adults this 30:2 pattern is the standard.