What are the primary causes of Pulseless Electrical Activity (PEA) arrest?

From the Guidelines

Pulseless Electrical Activity (PEA) arrest is primarily caused by reversible conditions, including the "5Hs and 5Ts" mnemonic, with pulmonary embolism (PE) being a significant and potentially reversible cause of PEA, as seen in 36% to 53% of PE-related cardiac arrests 1. The 5Hs include Hypovolemia (severe fluid loss from bleeding or dehydration), Hypoxia (insufficient oxygen), Hydrogen ion excess (acidosis), Hypo/Hyperkalemia (abnormal potassium levels), and Hypothermia (dangerously low body temperature). The 5Ts consist of Tension pneumothorax (collapsed lung), Tamponade (cardiac compression from fluid), Toxins/poisons (drug overdose or toxic substances), Thrombosis (coronary - heart attack, or pulmonary - blood clot in lungs), and Trauma. When treating PEA, it's essential to identify and address these underlying causes while performing high-quality CPR and administering epinephrine 1mg IV/IO every 3-5 minutes, as prompt systemic anticoagulation is generally indicated for patients with massive and submassive PE to prevent clot propagation and support endogenous clot dissolution over weeks 1. Some key points to consider in the management of PEA include:

• Hypovolemia requires fluid resuscitation
• Hypoxia needs oxygenation and ventilation
• Acidosis may require sodium bicarbonate
• Electrolyte abnormalities need specific corrections
• Tension pneumothorax requires needle decompression
• Cardiac tamponade needs pericardiocentesis
• Pulmonary embolism may require thrombolytic therapy, surgical or percutaneous mechanical embolectomy, or extracorporeal cardiopulmonary resuscitation (ECPR) 1. It is crucial to note that the management of acute PE is determined by disease severity, and fulminant PE, characterized by cardiac arrest or severe hemodynamic instability, defines the subset of massive PE that is the focus of these recommendations 1.

From the Research

Primary Causes of Pulseless Electrical Activity (PEA) Arrest

The primary causes of PEA arrest can be categorized into several key areas, including:

• Hypoxia: This is one of the most frequent causes of PEA, as seen in a study published in the Swiss medical weekly 2.
• Acute coronary syndrome: This condition is also a common cause of PEA, with a frequency of 12.5% in one study 2.
• Trauma: Trauma is another significant cause of PEA, with a frequency of 12.5% in the same study 2.
• Hypovolemia: Although less frequent, hypovolemia is still a notable cause of PEA, as mentioned in the "4H&4T" mnemonic and supported by a study in Resuscitation 3.
• Cardiac tamponade: This condition is a classic cause of PEA, as it can lead to a decrease in cardiac output and ultimately result in PEA, as discussed in a study in Anesthesia and analgesia 4.
• Tension pneumothorax: This is another critical cause of PEA, as it can lead to a decrease in cardiac output and ultimately result in PEA, as mentioned in the "4H&4T" mnemonic and supported by a study in the Swiss medical weekly 2.
• Thrombosis (pulmonary and coronary): Both pulmonary and coronary thrombosis can lead to PEA, as they can cause a decrease in cardiac output and ultimately result in PEA, as discussed in a study in the Journal of the American Heart Association 5.
• Toxins: Certain toxins can cause PEA, as they can disrupt the normal functioning of the heart, as mentioned in a study in Internal medicine (Tokyo, Japan) 6.
• Hypothermia: Hypothermia is another cause of PEA, as it can lead to a decrease in cardiac output and ultimately result in PEA, as discussed in a study in the Swiss medical weekly 2.
• Severe left ventricular dysfunction: This condition can also lead to PEA, as it can cause a decrease in cardiac output and ultimately result in PEA, as discussed in a study in the Journal of the American Heart Association 5.
• Metabolic acidosis: Severe metabolic acidosis, such as in alcoholic ketoacidosis, can also cause PEA, as discussed in a study in Internal medicine (Tokyo, Japan) 6.

Diagnostic Approaches

To diagnose the underlying cause of PEA, several approaches can be used, including:

• Electrocardiography: This can help identify any abnormalities in the heart's electrical activity, as discussed in a study in Anesthesia and analgesia 4.
• Pulse oxygen saturation: This can help identify any issues with oxygenation, as discussed in a study in Anesthesia and analgesia 4.
• End-tidal carbon dioxide: This can help identify any issues with ventilation, as discussed in a study in Anesthesia and analgesia 4.
• Blood pressure: This can help identify any issues with cardiac output, as discussed in a study in Anesthesia and analgesia 4.
• Cardiac ultrasound: This can help identify any structural issues with the heart, such as cardiac tamponade or hypovolemia, as discussed in a study in Resuscitation 3.
• Computed tomography: This can help identify any issues with the lungs or other organs, as discussed in a study in the Swiss medical weekly 2.
• Echocardiography: This can help identify any issues with the heart's structure or function, as discussed in a study in the Journal of the American Heart Association 5.