Final answer:
The critical element of Basic Life Support is performing chest compressions that are hard, fast, and effective, which helps maintain blood flow during CPR until professional help arrives or the heart resumes beating.
Step-by-step explanation:
One critical element of Basic Life Support (BLS) is chest compressions that are hard, fast, and effective. During the emergency procedure of cardiopulmonary resuscitation (CPR), if the heart stops beating, it's crucial to manually compress the heart by applying pressure to the sternum between the T4 and T9 vertebrae. This movement should be at least 5 cm deep and at a rate of 100 compressions per minute, which helps to maintain blood flow, especially to vital organs like the brain to prevent irreversible damage or death of neurons. Proper training and certification in CPR are extremely important as improper technique can cause serious harm to the patient, including broken ribs or damage to the liver.