What is the recommended compression-to-breath ratio for a single rescuer performing CPR on an adult?

• A. 15 compressions to 2 breaths
• B. 30 compressions to 2 breaths
• C. 30 compressions to 1 breath
• D. 20 compressions to 2 breaths

Answer: (B)

For an adult with a single rescuer, the recommended rhythm is 30 compressions followed by 2 breaths. This balance keeps blood flowing effectively while providing enough oxygen to the lungs. Aim for a compression rate of about 100–120 per minute and a depth of about 2 inches (5 cm), allowing full recoil after each compression. After 30 compressions, give two breaths, each lasting about 1 second and producing visible chest rise, then immediately resume compressions. Continue this cycle until the person shows signs of life or professional help arrives. The other ratios are designed for different rescuer situations or would reduce effectiveness for an adult.