What Is PEA Arrest & How Is PEA Treated?

What Is PEA Arrest? Pulseless electrical activity (PEA) is also known as electromechanical dissociation. It’s a clinical condition in which a patient experiences unresponsiveness in conjunction with a pulse that cannot be felt even when applying sufficient electrical discharge.
The electrical impulse is relevant but not sufficient to restart the heart because something else is going on in a PEA arrest.

How Common Is PEA Arrest?

PEA arrests are a surprisingly common occurrence in the hospital setting.

A study reported in NIH.gov found that 68% of tracked in-hospital deaths and 10% of all in-hospital deaths could be attributed to pulseless electrical activity.

A PEA arrest is the first documented rhythm in as many as 38% of adults experiencing hospital cardiac arrest (IHCA).

Certain medications such as beta-blockers and calcium channel blockers may alter ventricular contractility. This leads to an increased chance of PEA arrest happening, and it is less likely that treatment will be successful. PEA arrest is most common in women, and the chance of this happening increases for those over 70, particularly among women.

How It Happens: Understanding the Dying Process

In order to understand how to save a life during a cardiac arrest, you need to take a look at the dying process. This begins with the loss of function of a vital organ, e.g., brain, heart, or lungs. If professionals cannot restore this organ, it causes other organ failures.

However, in the case of a PEA arrest, the vascular system has collapsed. Without the vascular system, that blood can’t get to other vital organs, so the brain and lungs stop. In reality, the vascular system should also be considered a vital organ. Now death begins. The heart continues to pump until it no longer has the oxygen it needs for cardiac functions. Loss of effective pulse happens next. This loss of pulse is the beginning of PEA arrest.

So a PEA arrest is not a primary cardiac arrest. It is a latter stage in the dying process that begins with the stopping of another vital organ: the brain, the lungs, or the vascular system for one reason or another.

Examples of PEA Arrest Causes

Hypoxia is one of the most common causes of PEA, leading to an estimated 1/2 of PEA events. With oxygen cut off, the heart no longer has the means with which to contract, even if the heart were otherwise fully capable of a contraction with electrical stimulation from an AED. Unless the oxygen is restored, the heart muscle will die, and death results. This patient probably needs intubation before shock will have an effect.

The same can occur with:

• • Decreased preload from hypovolemia (loss of blood impairing atrial contractions)…This is the second most common cause of PEA.
  • Increased afterload from something like vascular resistance
  • Poor contractility, usually caused by acidosis or a reduction in calcium concentration

What Are The Reversible Causes of Cardiac Arrest (H and T)?

Experts break down the reversible causes of cardiac arrest into two primary categories, conveniently called H and T, or H’s & T’s. Any of the H and T may lead to a PEA.
The H’s are:

• Hypovolemia – Loss of blood volume (bleeding out)
• Hypoxia – Loss of Oxygen
• H+ (acidosis) or Metabolic Acidosis, an increase in hydrogen
  concentration in the body leading to a low serum bicarbonate
• Hypo/Hyperkalemia – Too little / too much potassium in the body
• Hypoglycemia – Low blood sugar
• Hypothermia – Low body temperature

The T’s are:

• Tension pneumothorax – ongoing entry and trapping of air in the pleural area around the lungs
• Tamponade (Cardiac) – Pressure caused by fluid or blood building up in the area outside the heart muscle in the heart sac
• Toxins – These could include sedatives, opioids, pesticides, acid, anaphylactic shock-inducing allergens, sodium-potassium blockers, etc.
• Thrombosis (pulmonary embolus) – A blockage, usually a blood clot that gets caught in the lungs
• Thrombosis (myocardial infarction) – Usually a blood clot in the vessels of the heart
• Trauma (physical) – A serious bodily injury, e.g., blunt force trauma or penetrating trauma

How Is PEA Treated?

If the PEA arrest is among the H and T, then it may be reversible. But you must treat the cause of the PEA arrest to reverse the state and obtain a shockable rhythm.

In a hospital setting, this may involve several Advanced Cardiac Life Support Techniques and procedures such as:

• Needle decompression of a collapsed lung
• Laryngeal tube / Intubation
• Blood infusion
• Body temperature correction
• Surgery to remove the pulmonary embolus
• Epinephrine

With that said, since hypoxia accounts for over 50% of PEA, epinephrine and ACLS airway management such as intubation are the emergency procedures stated in the ACLS Cardiac Arrest Algorithm. These measures are more about buying time so that the cause can be addressed. That may require surgery.

According to the algorithm, if you have a shockable rhythm, you shock before intubating the patient. But if they have a non-shockable rhythm (PEA/Asystole), you prioritize intubation without restoring oxygen, since the heart will stay unshockable until you do.

What’s the Difference Between PEA and Asystole?

The two are related cardiac rhythms, since they are both potentially deadly and non-shockable rhythms, requiring intervention before you can shock.

An Asystole is a flat line ECG, so you may have subtle movement away from the baseline (a drifting flatline). But you cannot perceive the cardiac electrical activity. A PEA is also one of many waveforms with no detectable pulse on ECG. Per International Liaison Committee on Resuscitation (ILCOR), any pulseless waveform can be called PEA, except ventricular fibrillation (VF), Ventricular tachycardia (VT), and Asystole.

An Asystole usually occurs because of trauma or accidental shock (touching a live wire, lightning, etc.), which stuns the heart muscle, causing the asystole. This can lead to an imbalance in the electrolytes sodium and potassium on the inside and outside of heart cells. Without those electrolytes, the heart cannot pulse or pick up on electrical impulses.

Because of the nature of the disruption, the heart experiencing Asystole no longer has the means to move an electrical current generated by defibrillation through the heart. It is therefore unshockable.

IV fluids can help restore this balance and are therefore another part of the ACLS cardiac arrest algorithm.

What Does an Asystole Look Like on ECG?

On ECG,

• The rhythm will have an almost flat line appearance
• No rate
• No P-Wave, so you cannot measure PR interval
• No QRS complexes

What Does a PEA Look Like on ECG?

• There may be any rhythm, which includes a flatline
• Any rate or none
• Possible P wave or none
• Possible PR or none
• Possible QRS complex or none

What Are Shockable vs. Non-shockable Rhythms?

A shockable rhythm is one caused by abnormalities in the electrical conduction in the heart. These include:

• Ventricular Tachycardia
• Ventricular Fibrillation
• Supraventricular Tachycardia

By addressing the cause of the PEA arrest, you can return the heart to one of these shockable rhythms. It’s critical that healthcare professionals stay vigilant when a PEA or Asystole converts back to a shockable rhythm. You can now use a defibrillator to shock and continue to follow your ACLS algorithm.

What’s the Difference Between PEA Arrest and Pseudo-PEA?

Pseudo-PEA and PEA both have organized activities that you can see on the monitor. And in both cases, you can’t detect a pulse using manual palpitations.

The defining factor is that in PEA arrests, there really is no pulse. There is no cardiac output. There is cardiac activity, but for some reason that activity is fruitless.

However, in the case of a Pseudo-PEA, even though a manual test detects nothing, you can detect a pulse by other means: arterial line, POCUS pulse check, ETCO2, and oxygen saturation waveform.

Why does this matter? Because a Pseudo-PEA may be shockable because it’s probably one of the three shockable rhythms. But depending on the devices used to determine “pulselessness”, one might falsely determine a PEA arrest and not shock.

What Happens If You Shock PEA? Why not shock a PEA Arrest?

In a PEA arrest, similar to Asystole, the heart doesn’t have the means to use the shock you’re sending it because the primary cause has yet to be corrected.

Shocking a heart in PEA arrest is like kicking a comatose patient in the abdomen (which we do not recommend). The kicking may move them around and cause what seem to be signs of life. But it doesn’t wake them up. It’s more likely to cause damage than help the situation.
With that said, the occurrence of Pseudo-PEA is common, so before making the decision not to shock, check your equipment, placement of leads, etc. to confirm PEA.

Can You Survive PEA?

Yes, you or your patient can survive PEA if you eliminate the primary cause of the PEA arrest to return the heart to a shockable rhythm. Then resume actions according to the ACLS cardiac arrest algorithm.

Which Medications Are Considered First for PEA?

Current ILCOR guidelines suggest that atropine is not to be used on PEA or Asystole. There is no evidence that it works, but there is also no evidence that it’s harmful.

Although research is ongoing in this area, ILCOR leans toward high-dose epinephrine. In limited studies, this has improved ROSC (Return of spontaneous circulation). With that said, there is some debate about how much epinephrine to administer, as some studies have shown no added benefits for administering higher than 1mg.

ILCOR has also suggested the use of a vasopressor, conveniently named vasopressin, which could replace the epinephrine or be used in conjunction with it, since Epinephrine loses additional effectiveness after 1mg. However, the two are more or less equal in effect, so for simplicity, you’ll only see epinephrine in the ACLS algorithm.

Some other medications to consider based on the cause of PEA and whether you can resume a shockable rhythm include:

• Adenosine
• Amiodarone
• Atropine
• Dopamine
• Lidocaine (only if Amiodarone isn’t available)
• Magnesium Sulfate
• Procainamide
• Sotalol

PALS PEA Arrest Management

For pediatric patients, you have a separate PALS cardiac arrest algorithm. The general flow for PALS PEA management is the same as that of an adult with the exception of PALS-specific CPR techniques and child-appropriate medication doses.

7 Tips for Managing a PEA

1. Recognize the Challenge

When a patient presents with a PEA arrest, your resuscitation team has a challenge ahead. This isn’t as straightforward as a shockable rhythm.
But follow your ACLS training for the scientifically best chance of success with a PEA arrest patient.

2. Know That Survival Rate Is Low

As medical providers, we always want to go in with a positive and practical mindset. But the truth is that, since PEA arrests are harder to manage, the survival rate is lower than if your patient came in with a shockable rhythm.

3. Think Of Your Team As the Holding Team

As a resuscitation team, you’re trying to buy your patient time for other medical treatments to work. The ACLS algorithm doesn’t solve the causes of PEA arrest. But it can lead to ROSC and stabilization, which gives a surgeon more time to address the issue and save the patient.

4. Know Your H and T

This mnemonic can help you remember an otherwise long list of causes of PEA that may be reversible.

5. Pay Attention to the Rhythm on ECG

Timing matters. When that rhythm becomes shockable, your team should be ready to shock all while continuing CPR and the other steps covered in the cardiac arrest algorithm.

6. Check Medical History When Available

You can often more quickly narrow the list of possible causes of PEA arrest if you know their medical history.
The patient may have had risk factors for hyperkalemia (electrolyte imbalance) or they may have recently left an addiction treatment facility.
Pulling this history may be a role for someone on your in-hospital code blue team.

7. Make Sure Team ACLS Training Is Up-to-Date

It’s critical that your whole code blue team works from the same playbook. Great teams think alike and follow a shared mental model (protocol).
Staying up-to-date with ACLS no longer requires spending a Saturday in a classroom. You can complete ACLS and PALS courses 100% online and get certified online too.

A PEA Arrest

A PEA arrest is a serious business, and your team will certainly have an uphill battle to ROSC. But through ACLS training, you can learn how to manage a PEA Arrest and improve the outcome for many patients.

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