Which of the following is a sign of effective chest compressions?

Visible rise of the chest with compressions is a clear indicator of effective chest compressions during CPR. When chest compressions are performed effectively, they create sufficient pressure to push blood through the heart and into the lungs, allowing for adequate ventilation and oxygenation. This rise in the chest demonstrates that air is entering the lungs, which is essential for delivering oxygen to the patient’s tissues.

Effective compressions should ideally result in both the movement of the chest and an increase in perfusion, as it indicates that blood flow is being adequately generated. The other options do not signify effective compressions in the same manner. A continuous rhythm without pauses is important but does not alone confirm that compressions are effective. An increased heart rate during compressions might not be relevant, as the heart may not effectively respond if it's in a critical state. A decrease in oxygen saturation indicates poor perfusion and oxygen delivery, which is the opposite of what is desired during resuscitation efforts. Thus, visible chest rise is the most reliable sign of effective chest compressions.