Final answer:
In managing an unresponsive patient, the immediate next step after finding them on the floor is to open the airway and assess breathing. CPR, including chest compressions, may follow if the patient is not breathing. An AED may be used thereafter if needed.
Step-by-step explanation:
When you find a 59-year-old man lying on the kitchen floor and determine that he is unresponsive, the next step in the assessment and management of this patient is c) Open the airway and assess breathing. This step is paramount before moving on to other interventions such as checking for a pulse, beginning chest compressions, or attaching an AED. It's important to ensure the airway is clear to permit breathing; if the patient is not breathing or only gasping, you would then begin CPR. According to current standards, chest compressions should be at least 5 cm deep and at a rate of 100 compressions per minute. It's important to note that the delivery of a large charge in a short burst by an automated external defibrillator (AED) can be vital to restart the heart during events like ventricular fibrillation; however, AED application comes after ensuring the patient has an open airway and is not breathing.