Review Question - QID 104190

This patient with cardiac arrest and an organized rhythm on the electrocardiogram has pulseless electrical activity (PEA). The most appropriate initial step in management is initiation of cardiopulmonary resuscitation (CPR).

PEA is defined as cardiac arrest with no palpable pulses in a patient with a discernible, organized rhythm on cardiac monitoring. Any patient in cardiac arrest with a rhythm other than ventricular tachycardia or ventricular fibrillation should undergo emergent CPR with chest compressions. A definitive airway should then be established with ventilation with 100% oxygen. IV access should be established to administer medications such as epinephrine and vasopressin per the ACLS algorithm. Atrial fibrillation is not a shockable rhythm in PEA, though cardioversion should be performed for hemodynamically unstable patients with a pulse if atrial fibrillation is thought to be the cause of the unstable hemodynamics. The treatable causes of PEA can be remembered as the 6 H's and 6 T's:

H: hypovolemia, hypothermia, hypoglycemia, hydrogen ions (acidosis), hyper/hypokalemia.

T: tamponade, tension pneumothorax, thrombosis (PE, MI), trauma (hypovolemia), tablets (drugs), toxins.

Oliver et. al review the pathophysiology and clinical manifestations of pulseless electrical activity. They describe the etiologies of cardiac arrest that more typically generate PEA, and recommend initiation of cardiopulmonary resuscitation as the first step in management.

Figure A demonstrates a cardiac rhythm strip showing pulseless electrical activity. Note that this rhythm is narrow-complex and regular. However, in the setting of a pulseless, unresponsive patient, this rhythm is deemed pulseless electrical activity

Incorrect Answers:
Answer 1: Defibrillation would be indicated for cardiac arrest due to ventricular fibrillation or pulseless ventricular tachycardia. However, pulseless electrical activity is not a rhythm that responds to defibrillation and it is therefore not indicated.

Answer 2: Endotracheal intubation will likely be indicated for this patient in cardiac arrest for airway protection and to ensure oxygenation. However, intubation should never delay or prevent high quality CPR and is therefore not the most appropriate initial step in management.

Answer 4: Intravenous epinephrine will be indicated in the management of this patient's cardiac arrest. However, the administration of epinephrine or any other medication should not delay or prevent the initiation of high quality CPR and is therefore not the most appropriate initial step in management.

Answer 5: Synchronized cardioversion is indicated in the management of hemodynamically unstable arrhythmias such as atrial fibrillation or ventricular tachycardia. It is not indicated in the management of cardiac arrest.

Bullet Summary:
For patients that develop pulseless electrical activity, the most appropriate initial step in management is the initiation of CPR.