The nurse sees on the cardiorespiratory monitor that the patient's cardiac rhythm has changed from normal sinus rhythm to ventricular fibrillation.The nurse knows that the most effective means of converting this rhythm is:

A) cardiopulmonary resuscitation (CPR) .
B) defibrillation.
C) oxygen.
D) precordial thump.

Cardiopulmonary resuscitation (CPR)should be performed until the defibrillator patches are applied,but it is not the most effective means of converting the electrical rhythm;rather it supports life until defibrillation can be performed.Oxygen should be administered during CPR,but it is not the means of converting the rhythm.Precordial thumps are controversial at best and would not be the most effective means of converting the rhythm.