What are the downward thrusts on the centre of the chest that help stimulate blood flow called?

The correct term for the downward thrusts applied to the center of the chest that stimulate blood flow during cardiopulmonary resuscitation (CPR) is "chest compressions." This technique is crucial in emergency situations, particularly when a person has stopped breathing or has no detectable pulse. Chest compressions work by compressing the heart between the sternum and the spine, which helps to manually pump blood throughout the body, thus maintaining circulation to vital organs and increasing the chances of survival until professional medical help arrives.

Chest compressions are conducted at a specific rate and depth and are an essential component of CPR procedures taught to both laypersons and medical professionals. The use of this term carries significance in first-aid training, emphasizing the importance of this action in life-saving efforts. The other options provided do not specifically refer to this action in the context of CPR, which reinforces why "chest compressions" is the most accurate choice.