A patient is considered refractory after ≥3 defib,  ≥3mg epinephrine, and 300mg amiodarone
The following therapies are largely based on case studies or case series
Consider holding further epinephrine (The Current State of Refractory VF)
Pulseless arrest
Spinal shock
Heat syncope
Cardiogenic shock
Electrical storm
Neurogenic shock
Hemorrhagic shock
Undifferentiated shock 