For unresponsive victims of all ages where the likely cause is asphyxial arrest, the lone healthcare provider should:

CPR can double or triple the victim’s chance of survival when performed immediately after collapse from ventricular fibrillation sudden cardiac arrest.

The correct compression ventilation ratio for CPR for an adult is:

Would you use a pediatric-specific AED system for a 14-year-old?

Sudden collapse in the adult is more likely a result of an arrhythmia that may require a defibrillator.