A cycle of CPR for a single rescuer on an adult includes which function?

• A. Blood Circulation
• B. Ventilation To Lungs
• C. BP Regulation
• D. Chest Structure Support

Answer: (B)

In adult CPR performed by a single rescuer, the cycle is defined by two distinct actions: chest compressions to push blood through the circulation and rescue breaths to ventilate the lungs. The function highlighted here is ventilation to the lungs because giving breaths is the explicit, repeatable action that interrupts the compressions to deliver air and oxygen directly to the airway. While chest compressions do help maintain blood circulation, the question points to the breathing component within the cycle, which is why ventilation to the lungs is the best choice. The other options—regulating blood pressure or supporting chest structure—aren’t performed as separate, explicit steps in the CPR cycle.