Red Cross Lifeguard Practice Test

As the first rescuer on the scene, how deeply should you compress the chest when performing CPR on an adult?

1. About 2 inches.

2. At least 2 inches but no more than 2.4 inches.

3. About 1½ inches.

4. At least 1 inch but no more than 2 inches.

The correct answer is: At least 2 inches but no more than 2.4 inches.

When performing CPR on an adult, the recommended compression depth is at least 2 inches but no more than 2.4 inches. This range is based on research that demonstrates effective chest compressions should be deep enough to create sufficient blood flow during compression, ensuring that the heart can pump blood effectively to the vital organs. Compressing the chest too shallowly may not generate the necessary pressure to circulate blood, making it less effective in providing circulation to a cardiac arrest victim. Maintaining the depth within the specified range ensures that the compressions are neither too shallow—resulting in inadequate blood flow—nor too deep, which could lead to potential injuries to the rib cage or internal organs. Thus, understanding and adhering to this guideline significantly enhances the chances of successful resuscitation in an adult experiencing cardiac arrest.