ACLS review: Pulseless VF/VT part 2

Primary Survey- CABs

·         Assess responsiveness and breathing

·         Active EMS system and call for defibrillator/monitor

·         Check pulse

·         Start CPR beginning with chest compressions

Ventricular Fibrillation:  Initial Rhythm

Note:    When a rhythm check by a manual defibrillator reveals VF/VT, the first provider should resume CPR while the second provider charges the defibrillator. Once the defibrillator is charged, CPR is paused to “clear” the patient for shock delivery. After the patient is “clear,” the second provider gives a single shock as quickly as possible to minimize the interruption in chest compressions (“hands-off interval”). The first provider resumes CPR immediately after shock delivery (without a rhythm or pulse check and beginning with chest compressions) and continues for 2 minutes. After 2 minutes of CPR the sequence is repeated, beginning with a rhythm check

Note:  The foundation of ACLS care is good BLS care, beginning with prompt high-quality bystander CPR and, for VF/pulseless VT, attempted defibrillation within minutes of collapse. For victims of witnessed VF arrest, prompt bystander CPR and early defibrillation can significantly increase the chance for survival to hospital discharge.  In adults with a prolonged arrest, shock delivery may be more successful after a period of effective chest compressions.

Attempt Defibrillation

·         Deliver one shock at 200J biphasic or 360 monophasic

·         Follow defibrillation with a period of uninterrupted CPR beginning with chest compressions

·         After 2 minutes (5 cycles of CPR), then recheck the victim’s rhythm.



Ventricular Fibrillation Refractory to Defibrillation at 200 J

Note:  When VF is present for more than a few minutes, the myocardium is depleted of oxygen and metabolic substrates. A brief period of chest compressions can deliver oxygen and energy substrates, increasing the likelihood that a perfusing rhythm will return after defibrillation (elimination of VF).

If the provider is unaware of the effective dose range of the device, the rescuer may use a dose of 200 J for the first shock and an equal or higher shock dose for the second and subsequent shocks

If VF is initially terminated by a shock but then recurs later in the arrest, deliver subsequent shocks at the previously successful energy level

Defibrillation vs synchronized cardioversion

·         Completely depolarizes the heart

·         Uses higher energy levels

·         Used for pulseless VT/VF

·         Unsynchronized with heart

·         Patient is pulseless

Defibrillation vs synchronized cardioversion

·         Interrupts the unstable rhythm

·         Uses lower energy level

·         Used for a variety of rhythms: SVT, AF, A flutter, VT

·         Synchronizes with the heart rhythm

·         Patient has a pulse


Reviewed 2/28/16