What should a nurse do first if a patient is unresponsive and not breathing?

When a patient is unresponsive and not breathing, the most critical action is to call for help and initiate CPR immediately. This response is vital because the absence of breathing indicates that the patient is in a life-threatening situation, potentially experiencing cardiac arrest or respiratory failure.

Initiating CPR helps to maintain blood circulation and oxygen delivery to vital organs, which is key to preserving brain function and increasing the chances of survival until emergency medical services can arrive. Immediate CPR can double or even triple a person's chance of survival in cases of cardiac arrest.

Calling for help ensures that additional resources and personnel are on the way to assist and provide more advanced care. This step is also essential because while performing CPR, having someone else trained to assist can improve the overall response time to the emergency situation.

Other options, like checking the pulse, administering oxygen, or performing a sternal rub, do not address the immediate need for circulation and oxygenation. Checking for a pulse may delay critical interventions when immediate action is required, and administering oxygen will not be effective if there is no circulation. Performing a sternal rub might provide an assessment of responsiveness, but it does not contribute to stabilizing the patient or addressing life-threatening conditions, making it a lower priority in this emergency scenario.