Pulseless electrical activity is a kind of irregular heart rhythm. It is a malfunction of your heart’s electrical system. When this happens, your heart’s electrical activity is too weak to make your heart pump. This causes your heart to stop beating. Without the right attention, PEA arrest is harmful. A significant percentage of all in-hospital deaths are attributed to PEA. Let us understand PEA in depth, while exploring its causes and treatment.
What is PEA in medical terms?
Pulseless electrical activity (PEA) is a condition where your heart stops as the electrical activity in your heart is too weak to make your heart beat. As your heart stops working, you go into cardiac arrest. You also do not have a pulse.
This non shockable heart rhythm means a defibrillator would not be able to correct it. If you do not treat it quickly, PEA causes sudden cardiac death within minutes. Electrical activity is necessary, but not sufficient. The presence of organized ventricular electrical activity is not accompanied by meaningful ventricular mechanical activity.
How does pulseless electrical activity work?
Now that you know what PEA is, let us understand how it works. At the beginning of every heartbeat, a cluster of cells creates an electrical current. This spreads to other areas of your heart. As the current passes slowly, the muscle reacts by flexing. This makes your heart squeeze and pump blood. Electrical current is detectable with the help of an electrocardiogram. With the help of PEA, your heart is not strong enough to pump blood to the body.
What are the two forms of PEA?
- Pseudo-PEA: This is a kind of PEA where the electrical activity causes your heart muscle to squeeze. This does move some blood. However, it is not a proper heartbeat and is not strong enough to pump blood well.
Hence, you do not have a pulse. There may be an electrical activity visible on the monitor, however it does not well correspond to an effective cardiac output. This is a result of severe cardiovascular compromise or shock. It is difficult to distinguish pseudo-PEA from true cardiac arrest. You can manage the situation by addressing other issues such as hypovolemia, cardiac tamponade, etc. Additionally, you must assess the condition rapidly to prevent further harm.
- True PEA: This is PEA where your heart has electrical activity without your heart muscle reacting to it. The blood is not moving, and there is no pulse. It is a critical medical emergency which requires immediate intervention.
Unlike other types of cardiac arrest, True PEA offers a unique challenge as the electrical system functions without generating an effective heartbeat. As alarming as it sounds, it needs prompt action, including CPR. You can manage and treat it by quickly recognizing it and improving outcomes.
What are the causes of PEA?
Are you thinking about what causes PEA? Keep reading to know the most common causes of PEA:
- Primary PEA: This happens because of a problem with your heart. It has a connection with cardiac arrest, as PEA cardiac arrest takes place together. This is a condition when the heart’s electrical activity is present, however the heart does not pump blood efficiently. This reduces circulation in the body and needs immediate attention. Prompt medical measures such as cardiopulmonary resuscitation can help restore functioning of the heart. This also helps boost circulation.
- Secondary PEA: This is PEA from an outside cause rather than from a problem with your heart. It occurs when the electrical activity of the heart appears normal, but has no heartbeat. Although you may find electrical signals in the heart, they do not result in a strong heartbeat that effectively pumps the heart. This indicates serious underlying issues, including severe shock or cardiac dysfunction. The causes of PEA are the following:
- Blood loss
- Lox oxygen levels
- Dehydration
- Pulmonary embolism
- ‘Hypothermia
- Irregular heart rhythms
- Trauma
- Toxic effects
- Air, blood, or fluid filling areas in your chest
Can PEA be caused by specific medical conditions or medications?
Yes, metabolic derangements such as hyperkalemia, acidosis, and hypokalemia are contributing factors. Drugs such as calcium channel blockers, digitalis, tricyclic antidepressants, or toxins are rare causes of PEA.
How do you determine the underlying cause of PEA in a patient?
To determine the cause of PEA in a patient, you must assess the potential reversible causes. You must use the ‘Hs and Ts’ mnemonic to remember the causes. This can guide the diagnosis and treatment procedure.
Hypovolemia:
Cause: Significant blood or fluid loss
Assessment: Look for hemorrhage or signs of shock, such as low blood pressure.
Management: Administer intravenous fluids.
Hypoxia:
Cause: Inadequate oxygenation
Assessment: Check the saturation levels and the airway latency to achieve proper ventilation.
Management: Offer supplemental oxygen and secure the airway.
Hydrogen ion:
Cause: Respiratory or metabolic acidosis.
Assessment: Check the blood gas results from CO2, pH, and bicarbonate levels.
Management: Give sodium bicarbonate and address the underlying cause to ensure ventilation.
Hyperkalemia/hypokalemia:
Cause: Abnormal potassium levels.
Assessment: Achieve serum potassium levels. Check for pulseless electrical activity
ECG changes.
Management: Give calcium chloride for hyperkalemia, along with insulin and glucose. However, for hypokalemia, give a replacement of potassium.
Hypothermia:
Cause: Low body temperature
Assessment: Check the body temperature.
Management: Rewarm the patient with the help of external and internal warming techniques.
Tension pneumothorax:
Cause: air pressure accumulation in the pleural space.
Assessment: Evaluate signs such as tracheal deviation, distended neck veins, and unequal breath sounds.
Management: Do needle decompression or chest tube insertion.
Tamponade:
Cause: fluid accumulation in the pericardial sac.
Assessment: Inspect for signs, including distended neck veins, muffled heart sounds, and hypotension.
Management: Perform pericardiocentesis. This will help in reducing pressure.
Toxins (drug overdose):
Cause: drug overdose
Assessment: Inspect signs of toxidrome and get a patient history. You can look out for laboratory tests.
Management: Give specific antidotes and offer supportive care.
Thrombosis:
Cause: Pulmonary embolism
Assessment: Check the individual’s medical history and the risk factors and signs, such as chest pain.
Management: Give thrombolytics and do a surgical embolectomy.
Thrombosis:
Cause: myocardial infarction
Assessment: Check the risk factors, the history, and the ECG changes.
Management: Give thrombolytics and perform percutaneous coronary intervention.
What are the immediate PEA treatment steps?
An electrocardiogram is the only way to know if a stopped heart involves PEA. The treatment, however, is always the same, irrespective of whether PEA is involved or not.
Effective and immediate CPR must be the top priority during cardiac arrest, especially in outside hospital settings. Continue CPR until emergency services arrive.
If PEA takes place in a hospital setting, here are the treatments to consider:
- Resuscitation: This is a significant part of the treatment, both inside and outside of hospital settings.
- Epinephrine: This medication helps restore your heart to a normal rhythm.
- Treat the cause of PEA: Secondary PEA means there is a specific cause such as electrolyte problems, blood loss, etc. Effective treatment can revive the heart and bring the normal rhythm back.
Read More: High-quality CPR: Overview, Components, and Technology
Are there specific medications or dosages used for PEA treatment?
Anticholinergic, inotropic, and alkalizing agents are beneficial in treating pulseless electrical activity (PEA). If the underlying rhythm is bradycardia in association with hypotension, then administer atropine. Additionally, you can also give sodium bicarbonate to patients experiencing systemic acidosis, tricyclic antidepressant overdose, or systemic acidosis.
Inotropic agents
These agents help increase the central aortic pressure and counter myocardial depression. The primary effects are cardiac stimulation, dilation of skeletal muscle vasculature, and bronchial smooth muscle relaxation.
Epinephrine (Adrenalin)
Epinephrine has alpha-agonist effects, including peripheral vascular resistance, systemic hypotension, and vascular permeability. The beta-agonist effects of epinephrine include chronotropic cardiac activity, bronchodilation, and positive inotropic effects.
Anticholinergic agents: These help improve conduction through atrioventricular mode. It does so by reducing vagal tone via muscarinic receptor blockade.
Atropine IV/M (Isopto)
Use atropine in the presence of bradycardia. Do not use it regularly. It functions by increasing heart rate through vagolytic effects, increasing cardiac output. The total vagolytic dose is 2 mg. Doses under 0.5 mg may increase bradycardia.
Alkalising agents: These are useful in the alkalinization of urine. Administer sodium bicarbonate in a routine manner, as it worsens intracerebral acidosis and intracellular acidosis. It does not reduce the mortality rate.
Sodium bicarbonate (Neut)
This is beneficial when the patient suffers from an overdose of bicarbonate-responsive acidosis, a tricyclic antidepressant, or a phenobarbital overdose. You must use it routinely.
What are the advanced life support (ALS) protocols for managing PEA?
Advanced life support (ACLS) protocols manage pulseless electrical activity and treat the underlying causes well. Here are the protocols to manage PEA:
Monitoring and diagnosis:
- Use a defibrillator: This device helps monitor the cardiac rhythm. By doing so, it confirms the absence of a pulse.
- Obtain IV/IO access: Establish intravenous (IV) or intraosseous (IO) access to administer drugs.
Identify reversible causes:
- Use the H’s and T’s mnemonics: Evaluate and treat reversible causes of PEA, including the following:
- Hypovolemia, hydrogen ions, hypoxia, hyperkalemia, and hypothermia.
- Ts: tension pneumothorax, toxins, tamponade, thrombosis.
- Administer drugs: Give 1 mg of epinephrine IV/IO every 3–5 minutes while administering resuscitation.
- Consider additional drugs: Depending on the suspected cause, consider drugs such as sodium bicarbonate for acidosis and calcium chloride.
Rhythm checks:
- Every 2 minutes: Wait for 2 minutes to check the rhythm and for signs of the return of spontaneous circulation. Give a brief pause.
- Identify shocks: Deliver a defibrillation shock if the rhythm changes to a shockable one.
- Advanced diagnostics and interventions:
- Ultrasound: Use ultrasound if available to diagnose conditions such as pneumothorax and cardiac tamponade.
- Labs and imaging: Get arterial blood gasses, electrolytes, and other laboratory tests at the earliest. Consider imaging studies such as chest X-rays to identify underlying issues.
Post-ROSC care:
- Optimize ventilation and oxygenation: Avoid hyperventilation and ensure adequate oxygenation.
- Hemodynamic support: Give vasopressors and fluids and maintain blood pressure and perfusion.
- Manage temperature: Consider TTM after ROSC and improve neurological outcomes.
Record all communication:
- Document everything: Record all actions, drugs offered, and responses of patients.
- Team communication: Communicate effectively within the resuscitation team.
Read More: Cardiac Arrest: Risk Factors, Symptoms, and Treatment
Conclusion
Pulseless electrical activity takes place along with cardiac arrest. It is crucial to understand PEA, especially in out-of-hospital settings. Effective cardiopulmonary resuscitation helps an individual regain their life. The ALS protocols manage PEA by performing high-quality CPR, providing adequate ventilation, and securing the airway. You must give epinephrine and check the rhythm in addition to diagnosing and giving therapeutic interventions. Effective care and team communication help improve patient outcomes.
