What is the workup for a Pulseless Electrical Activity (PEA) arrest?

Workup of PEA Arrest

During PEA arrest, immediately begin high-quality CPR while simultaneously performing a focused bedside ultrasound and systematically evaluating the H's and T's (reversible causes), with epinephrine 1 mg IV/IO every 3-5 minutes, prioritizing identification and treatment of the underlying cause over prolonged diagnostic workup. 1, 2, 3

Immediate Actions During Resuscitation

Primary Resuscitation Protocol

• Start high-quality CPR immediately: Push hard (at least 2 inches/5 cm) and fast (100-120/min) with complete chest recoil, minimizing interruptions to less than 10 seconds. 1
• Establish vascular access (IV or IO) as soon as possible without interrupting compressions. 1, 2
• Administer epinephrine 1 mg IV/IO every 3-5 minutes throughout the resuscitation. 1, 2
• Place an advanced airway (endotracheal tube or supraglottic device) early, as hypoxia is a frequent cause of PEA. 1, 2
• Once airway is secured, provide 1 breath every 6 seconds (10 breaths/min) with continuous chest compressions. 1

Critical Diagnostic Workup During CPR

Bedside cardiac ultrasound is the single most important diagnostic tool and should be performed immediately without interrupting compressions for more than 10 seconds. 2, 3 This helps:

• Confirm true PEA versus pseudo-PEA (cardiac motion present but insufficient for pulse)
• Identify reversible causes with high accuracy: cardiac tamponade (100% sensitivity), pulmonary embolism (100% sensitivity, 97% specificity), and myocardial infarction (86% sensitivity, 94% specificity) 3

Systematic Evaluation of Reversible Causes (H's and T's)

During each 2-minute CPR cycle, systematically recall and evaluate for the following reversible causes: 2, 3

The H's:

• Hypovolemia: Administer IV/IO crystalloid bolus or blood products if hemorrhage suspected. 3
• Hypoxia: Ensure adequate oxygenation with 100% oxygen and effective ventilation. 3
• Hydrogen ion (acidosis): Consider sodium bicarbonate if prolonged arrest or known severe acidosis. 3
• Hypo/Hyperkalemia: Check point-of-care potassium if available; treat empirically if high suspicion (calcium chloride for hyperkalemia). 3
• Hypothermia: Check core temperature; initiate rewarming if <35°C. 3

The T's:

• Tension pneumothorax: Perform immediate needle decompression at 2nd intercostal space, mid-clavicular line if clinically suspected (unilateral absent breath sounds, tracheal deviation, distended neck veins). 3
• Tamponade (cardiac): Ultrasound shows pericardial effusion; perform emergency pericardiocentesis. 3
• Toxins: Consider specific antidotes (e.g., higher epinephrine doses for β-blocker/calcium channel blocker overdose, naloxone for opioids). 2
• Thrombosis (pulmonary): If suspected PE, consider thrombolysis, surgical embolectomy, or mechanical embolectomy as emergency treatment, with early systemic thrombolysis associated with improved outcomes. 2
• Thrombosis (coronary): Particularly suspect in patients with known severe left ventricular dysfunction, as acute coronary occlusion causes PEA within 2 minutes in this population. 4
• Trauma: Evaluate for hemorrhage, tension pneumothorax, or cardiac injury. 3

Monitoring and Prognostic Indicators

ECG Pattern Analysis

• 90% of PEA patients have widened QRS complexes (>120 ms), with 63% showing "wide-slow" pattern (widened QRS with bradycardia). 5
• Improving ECG characteristics during resuscitation predict ROSC: Increasing heart rate and narrowing QRS width in the last 3-6 minutes before ROSC are favorable signs. 6
• Continue aggressive resuscitation if ECG shows improvement, as this indicates potential for recovery. 6

Ultrasound Findings

• Pseudo-PEA (visible cardiac wall motion on ultrasound) has better prognosis than true PEA (no wall motion). 2, 7
• Presence of any cardiac contractility, even if ineffective, suggests earlier stage in dying process and warrants continued aggressive resuscitation. 7

Critical Pitfalls to Avoid

• Do not delay treatment while searching for causes—continue uninterrupted CPR while systematically evaluating. 3
• Do not use fixed/dilated pupils as a reason to stop resuscitation, as epinephrine causes pupillary dilation and patients have achieved favorable neurological outcomes despite this finding. 2
• Do not prematurely terminate resuscitation in PEA, especially in young patients or those with secondary PEA after VF/VT (15% chance of ROSC per minute). 2, 8
• Do not interrupt compressions for more than 10 seconds for any diagnostic procedure, as this reduces coronary perfusion pressure. 3
• Do not assume pulse assessment is reliable—physical examination findings are frequently misinterpreted during cardiac arrest; use ultrasound for confirmation. 2

Special Considerations

Type of PEA Matters for Prognosis

• Primary PEA (initial rhythm): 10% chance of ROSC per minute, peaking at 4 minutes. 8
• Secondary PEA after VF/VT or after transient ROSC: 15% chance of ROSC per minute—these patients warrant particularly aggressive resuscitation. 8
• Secondary PEA after asystole: 10% chance of ROSC per minute, peaking at 7 minutes. 8

Advanced Airway Priority

Placement of an advanced airway is theoretically more important in PEA than in VF/pulseless VT arrests given the high frequency of hypoxia as a causative factor. 2