Pulseless Electrical Activity (PEA) and Patient Survival
Pulseless electrical activity (PEA) does not mean the patient is dead, but represents a critical cardiac arrest state requiring immediate intervention with a poor but not zero chance of survival.
Understanding PEA
PEA is defined as cardiac electrical activity (visible on ECG) without a detectable pulse or blood pressure 1. It represents a specific type of cardiac arrest that:
- Occurs when there is organized electrical activity on the ECG but no effective mechanical contraction of the heart 2
- Is distinct from other cardiac arrest rhythms like ventricular fibrillation (VF), ventricular tachycardia (VT), and asystole 1
- Has been increasing in frequency over the past 10-20 years as a presenting cardiac arrest rhythm 2
Survival Rates and Prognostic Factors
While PEA has traditionally been associated with poor outcomes, survival is possible and depends on several factors:
Initial electrical frequency in PEA strongly predicts survival:
ECG changes during resuscitation can predict return of spontaneous circulation (ROSC):
- Increasing heart rate and decreasing QRS complex width during advanced life support are significantly more prevalent in patients who achieve ROSC 4
Pathophysiology of PEA
PEA represents a late phase in the clinical dying process but is not itself death 5:
- Echocardiographic studies have shown that PEA follows a continuous process from pseudo-PEA (with ineffective contractions) to true PEA and then potentially to asystole 5
- PEA often results from tissue hypoxia and metabolic substrate depletion 5
- In cases of acute coronary occlusion, pre-existing left ventricular dysfunction significantly increases the likelihood of PEA as the initial arrest rhythm 6
Management of PEA
Guidelines recommend a systematic approach to PEA management:
Immediate Actions
- Begin high-quality CPR with minimal interruptions in chest compressions 1
- Establish vascular access (IV/IO) 1
- Administer epinephrine 0.01 mg/kg (maximum 1 mg) every 3-5 minutes while CPR continues 1
- Consider and treat potentially reversible causes 1
Advanced Interventions
For suspected pulmonary embolism as the cause of PEA:
For specific causes like β-blocker or calcium channel blocker overdose:
Post-Resuscitation Care
- If ROSC is achieved, comprehensive post-cardiac arrest care should be initiated, including consideration of targeted temperature management and addressing the underlying cause 1
Important Considerations
PEA is often caused by reversible conditions (the "H's and T's"), including hypovolemia, hypoxia, hydrogen ion (acidosis), hypo/hyperkalemia, hypothermia, toxins, tamponade, tension pneumothorax, thrombosis (coronary or pulmonary), and trauma 1
The presence of PEA should prompt immediate search for and treatment of these underlying causes 1
Single-shock strategy (as opposed to stacked shocks) is recommended for defibrillation if the rhythm changes to a shockable rhythm 1
Vasopressors may improve ROSC and short-term survival, though evidence for improved long-term outcomes is limited 1
Conclusion
PEA represents a critical emergency requiring immediate intervention but does not itself signify death. With proper resuscitation efforts focused on high-quality CPR, administration of epinephrine, and identification and treatment of underlying causes, survival is possible, particularly in patients with higher initial electrical frequencies.