What should be your immediate action if a patient who was successfully shocked back into a normal rhythm becomes cyanotic and pulseless during transport?

Starting CPR and requesting additional EMS support is the appropriate immediate action in this scenario because the patient has become cyanotic and pulseless, indicating a life-threatening condition that requires urgent intervention. Cardiopulmonary resuscitation (CPR) is critical in helping to circulate blood and oxygen to vital organs, which is essential when a patient is in cardiac arrest.

In situations like this, the priority is to restore circulation and provide oxygenation as quickly as possible. By initiating CPR, you are performing the most effective intervention available to improve the chances of survival. This action is also paired with the request for additional EMS support, which is prudent to ensure that more advanced care can be provided promptly, such as medications or advanced airway management.

Other actions, such as monitoring vital signs or administering oxygen, are important but do not have the same immediacy in a state of pulselessness. Waiting for guidance without taking action is not suitable, as every second counts in a cardiac emergency. Intubating the patient, although vital in some contexts, is not the first step when CPR is needed; it's crucial only after ensuring that effective circulation efforts are initiated. Therefore, the immediate focus must be on CPR and obtaining additional support to improve the patient's condition