We are using the 'pit crew' CPR or CPR-hd, whatever you want to call it.
If the arrest is presumed to be cardiac(not cardiac arrest secondary to hypoxia, overdose, sepsis, etc) and either witnessed by somebody or presumably recent, then 200 compressions are to be started immediately(or shock if CPR is in progress already on arrival and they're in VF/VT), a NRB masked placed on the pt, and an IO placed with the first round of epi given. We are not to place an advanced airway or provide BVM ventilations; we go right to NRB. We do not try for an IV; we go straight to an IO. It's all about compressions, drugs, and defibrillation initially. After 4 rounds of 200 compressions then we fall back into our 'normal' cardiac arrest protocol(which basically means putting an advanced airway in at that point)