Final answer:
The most appropriate action to ensure effective chest compressions during CPR is to allow the chest to fully recoil between compressions to ensure proper blood refill in the heart.
Step-by-step explanation:
To ensure effective chest compressions during CPR, the most appropriate action is allowing the chest to fully recoil between compressions. This allows the heart to adequately refill with blood between compressions. Compressing the chest to a shallow depth would not provide adequate circulation, and positioning the hands at the upper part of the victim's chest could lead to ineffective compressions and potential injury.
Moreover, placing the victim on a soft surface would absorb some of the compressive forces, thereby reducing the effectiveness of chest compressions. Proper hand placement is crucial and should be on the sternum between the lines at T4 and T9 to avoid severe damage such as driving the xiphoid process into the liver. High-quality chest compressions should be performed at least 5 cm deep and at a rate of 100 compressions per minute.