Final answer:
After two initial ventilations, you should perform chest compressions on a 64-year-old female in cardiac arrest, maintaining a rate of 100 compressions per minute and compressing the chest at least 5 cm deep until professional help arrives or the patient revives.
Step-by-step explanation:
After providing two initial ventilations to a 64-year-old female who has collapsed in cardiac arrest, you should immediately begin chest compressions. According to current standards, it's crucial to perform compressions at a depth of at least 5 cm and at a rate of 100 compressions per minute, which coincides with the beat of the Bee Gees' song "Staying Alive."
This action is designed to manually compress the blood within the heart to maintain flow through the pulmonary and systemic circuits, especially critical for brain health as neuron death occurs within minutes of losing blood flow. CPR should be continued until the patient either regains spontaneous heart contractions or is pronounced dead by a qualified healthcare professional. Properly placing your hands on the sternum between T4 and T9 will ensure effective compressions during CPR.