Final answer:
In the case of ventricular tachycardia with an unresponsive patient, a Patient Care Technician should palpate the pulse at the common carotid artery. This site offers a reliable indication of heart activity in an emergency situation where quick actions may be necessary to save the patient's life.
Step-by-step explanation:
A Patient Care Technician (PCT) encountering an adult patient who is unresponsive and experiencing ventricular tachycardia should immediately check for a pulse. In such emergency situations, the common carotid artery in the neck is the most appropriate site for palpating the pulse due to its accessibility and the strength of the pulse that can usually be felt there.
If manual palpation is unsuccessful or there's doubt, the PCT may use a commercial electronic device to measure the pulse. Prompt diagnosis is essential as ventricular tachycardia is a life-threatening condition requiring immediate medical intervention, potentially including cardiopulmonary resuscitation (CPR) and use of a defibrillator.