In one cycle of CPR for an adult by a single rescuer, how many chest compressions and breaths are given?

• A. 10 And 2
• B. 15 And 2
• C. 20 And 3
• D. 30 And 2

Answer: (B)

When one rescuer is performing CPR on an adult, the standard cycle is 30 chest compressions followed by 2 rescue breaths. This 30:2 pattern balances delivering enough chest compressions to maintain blood flow with the opportunity to ventilate the person. Aim for compressions at about 100–120 per minute and a depth of roughly 2 inches (5 cm) with complete chest recoil between pushes. After delivering 30 compressions, open the airway and give 2 breaths, each lasting about one second and making the chest rise. Then repeat the cycle until help arrives or the person shows signs of life. For contrast, with two rescuers, the cycle can be 15 compressions and 2 breaths to reduce fatigue, but with a single rescuer the recommended rhythm is 30:2.