1. What is the recommended minimum chest compression fraction (CCF) for high-quality cardiopulmonary resuscitation (CPR)? A. 50% B. 60% C. 70% D. 80% Answer: C. 70% Rationale: The American Heart Association recommends a minimum CCF of 70% to ensure that the patient receives the maximum benefit from CPR. A higher CCF increases the likelihood of favorable outcomes. 2. Which of the following is NOT a factor that can affect the chest compression fraction? A. Rescuer fatigue B. Frequent pulse checks C. Use of mechanical CPR devices D. High-quality chest compressions Answer: D. High-quality chest compressions Rationale: High-quality chest compressions are essential for effective CPR and do not negatively affect the CCF. Factors such as rescuer fatigue, frequent pulse checks, and not using mechanical CPR devices can lower the CCF. 3. When measuring CCF, which device is commonly used to monitor the quality of chest compressions? A. Electrocardiogram (ECG) B. Pulse oximeter C. Capnography D. Feedback device Answer: D. Feedback device Rationale: Feedback devices are used to provide real-time information on the quality of chest compressions, including rate, depth, and CCF, helping to guide rescuers in delivering high-quality CPR. 4. In the context of CPR, what does the 'fraction' in chest compression fraction refer to? A. The ratio of compressions to ventilations B. The proportion of time in which chest compressions are performed