Final answer:
The question concerns the correct procedure for administering CPR, specifically when to move from Block C to Block D if the patient's heart rate remains low despite proper execution of chest compressions and positive-pressure ventilation.
Step-by-step explanation:
The question pertains to the protocol that should be followed when conducting cardiopulmonary resuscitation (CPR). It refers to a specific point in the CPR procedure - after Block C, which indicates that if the patient's heart rate (HR) remains below a certain threshold and positive-pressure ventilation (PPV) along with proper chest compressions are being administered effectively, one should then proceed to Block D of the resuscitation process. It is imperative to continue performing high-quality chest compressions to maintain blood flow, particularly to vital organs like the brain, where irreversible damage can occur within minutes due to loss of blood flow. The hands should be properly positioned on the sternum, specifically between the lines at T4 and T9; this allows for manual compression of the heart, forcing blood into the pulmonary and systemic circuits.
During CPR, compressions should be at least 5 cm deep with a rate of 100 compressions per minute. This rate is comparable to the rhythm of the song 'Staying Alive' by the Bee Gees. CPR is a critical life-saving technique that is generally continued until the patient's heart starts beating again on its own or the patient is declared deceased by a healthcare professional.