From the Guidelines
The most common causes of pulseless electrical activity (PEA) arrest are the "H's and T's", which include Hypovolemia, Hypoxia, Hydrogen ion excess, Hypo/Hyperkalemia, Hypothermia, Tension pneumothorax, Tamponade, Toxins/poisons, Thrombosis (pulmonary embolism), and Thrombosis (myocardial infarction) 1. When treating PEA, it is essential to rapidly identify and address these underlying causes while performing high-quality CPR.
- The primary H's include:
- Hypovolemia (severe fluid loss)
- Hypoxia (lack of oxygen)
- Hydrogen ion excess (acidosis)
- Hypo/Hyperkalemia (abnormal potassium levels)
- Hypothermia
- The main T's include:
- Tension pneumothorax (collapsed lung)
- Tamponade (cardiac)
- Toxins/poisons
- Thrombosis (pulmonary embolism)
- Thrombosis (myocardial infarction) According to the 2020 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1, understanding these causes is crucial because PEA has a poor prognosis unless the underlying cause is quickly identified and treated.
- Treatment of these conditions includes:
- Fluid resuscitation for hypovolemia
- Oxygenation and ventilation for hypoxia
- Proper ventilation and sometimes sodium bicarbonate for acidosis
- Appropriate replacements for electrolyte abnormalities
- Immediate needle decompression followed by chest tube placement for tension pneumothorax
- Pericardiocentesis for cardiac tamponade
- Thrombolytics for pulmonary embolism It is also important to note that some noncardiac etiologies, such as opioid overdose, are becoming increasingly common in the out-of-hospital setting, and treatment for reversible underlying causes is essential for improving outcomes 1.
From the Research
Common Causes of Pulseless Electrical Activity (PEA)
- Myocardial infarction (MI) and massive pulmonary embolism (MPE) are common causes of cardiac arrest, including PEA 2
- Cardiac arrest of cardiac origin occurred in 63% of all patients, with 35% of them due to acute myocardial infarction, while non-cardiac causes were mostly due to pulmonary causes (15% of all patients) 3
- PEA is more commonly associated with MPE versus MI due to near complete obstruction of pulmonary blood flow with an intact electrical conduction system 2
Other Causes of Cardiac Arrest
- Aortic dissection/rupture, exsanguination, intoxication and adverse drug reactions, metabolic, cerebral, sepsis and accidental hypothermia each ranged between 1 and 4% of the cohort 3
- Cardiac arrhythmias and conduction defects, left ventricular failure and cardiogenic shock, rupture of the heart, and thromboembolism are complications of acute myocardial infarction that can lead to cardiac arrest 4
Diagnostic Challenges
- Differential diagnosis between right ventricular myocardial infarction and pulmonary embolism can be challenging due to similar clinical pictures, unspecific electrocardiographic changes, and unspecific biological markers 5
- Pulmonary embolism may present with abnormal EKG and biomarkers that appear to be an acute coronary syndrome, even ST-elevation myocardial infarction (STEMI) 6