Why Is Defibrillation Important? | How Does a Defibrillator Work?

Monitored patient

• If ventricular fibrillation is recognized within 2 minutes, give precordial thump, assess rhythm and carotid pulse, and expose the anterior chest.
• If within 2 minutes of detection of ventricular fibrillation, defibrillate before initiating cardiopulmonary resuscitation (CPR). Beyond 2 minutes, start resuscitation efforts immediately.

Unmonitored patient

• Expose the anterior chest and remove jewelry in the area.
• Start CPR immediately
• Apply interface material to the patient (gel pads) or the paddles (gel, paste). The electrode paddles should be in firm contact with the patient’s skin.
• Remove oxygen from the immediate area.
• A second person should turn on the defibrillator to the prescribed setting. The American Heart Association recommends that initial defibrillation should be 200 to 300 joules of delivered energy. A second attempt at the same level should be given if the first attempt is unsuccessful. A third attempt with an increase of energy level to 360 joules should be attempted. Allow only approximately 5 seconds between successive shots to assess rhythm and pulse.

Apply electrodes in one of three ways:

Anterolateral position: 

• Apply one electrode just to the right of the upper sternum below the clavicle and the other electrode only to the left of the cardiac apex or left nipple 

Anteroposterior position: 

• The anterior paddle is held with pressure on the middle sternum while the patient lies on the posterior paddle under the left infrascapular region.

Alternate position:

• Posterior paddle in the right infrascapular area and anterior paddle over the left apex.
• Grasp the paddles only by the insulated handles. Charge the paddles. Once paddles are charged, give personnel the command to stand clear of the patient and the bed. Glance to make sure all are away from the patient and bed.
• Push the discharge buttons on both paddles simultaneously while placing about 25 pounds of pressure onto each paddle
• Remove the patient’s paddles immediately after the shock is administered (unless paddles are being used as monitor leads). Resume CPR efforts until stable rhythm, spontaneous respirations, pulse, and blood pressure return. Look at the electrocardiograph monitor to determine the specific therapy for the resultant electrical mechanism. Further high-energy counter shocks may be necessary.