Final answer:
The technician should first start chest compressions to restore circulation to the patient's vital organs. Following this, the use of an automated external defibrillator (AED) can be considered.
Step-by-step explanation:
In the scenario where a patient becomes unresponsive, stops breathing, and does not have a pulse while undergoing a 12-lead EKG, the first action the technician should take is to start chest compressions. The priority in such emergency situations is to restore blood flow to vital organs, especially the brain, to prevent irreversible damage. According to current standards, chest compressions should be at least 5 cm deep and at a rate of 100 compressions per minute. This action is in alignment with the current emphasis on high-quality chest compressions over artificial respiration in the initial phase of cardiopulmonary resuscitation (CPR).
After starting chest compressions, the technician should then consider the use of an automated external defibrillator (AED), which is designed for laypersons and can diagnose the patient's heart condition before delivering an appropriate electrical shock. However, the immediate commencement of CPR, particularly chest compressions, is crucial and takes precedence over retrieving an AED or providing breaths to the patient.