Final answer:
The preferred method for medication administration during cardiac arrest with refractory ventricular fibrillation is IV or IO. AEDs are also now commonly used in public places for defibrillation by nonmedical personnel, followed by CPR.
Step-by-step explanation:
If a patient is in cardiac arrest and ventricular fibrillation has been refractory to an initial shock, and no pathway for medication administration is in place, the preferred method for medication administration is IV or IO (intravenous or intraosseous). These routes are the fastest and most reliable ways to deliver medications during a code blue situation. A central line is another option, but it typically requires more time and expertise to insert. An endotracheal tube may be used for medication administration, but the absorption is less predictable than IV or IO methods. The external jugular vein could be used as a last resort but it is less preferable due to difficulty in accessing and maintaining during CPR.
Modern emergency response now includes the use of automated external defibrillators (AEDs), which are available in public places and can be used by nonmedical personnel. These devices provide verbal instructions to guide the rescuer through the defibrillation process. They analyze the patient's heart rhythm and deliver a shock with appropriate energy and waveform if necessary. Post-defibrillation, continuous CPR is recommended until medical help arrives or the patient shows signs of recovery.