What are the management strategies for a Pulseless Electrical Activity (PEA) arrest with reversible causes, including the use of sodium bicarbonate, calcium, and magnesium?

Management of PEA Arrest with Reversible Causes

Immediate Management Priorities

High-quality CPR with minimal interruptions remains the cornerstone of PEA management, combined with immediate systematic evaluation for reversible causes using the "H's and T's" framework and bedside ultrasound. 1, 2

Core Resuscitation Protocol

• Begin immediate high-quality CPR with chest compressions at 100-120/minute and depth of at least 2 inches, minimizing interruptions to maintain coronary perfusion pressure 3, 1
• Administer epinephrine 1 mg IV/IO every 3-5 minutes as the primary vasopressor throughout resuscitation 3, 1
• Establish vascular access (IV or IO if IV not readily available) for medication administration 3, 1
• Secure advanced airway as hypoxia is a leading cause of PEA, making airway management theoretically more critical than in VF/VT arrests 2

Systematic Evaluation for Reversible Causes

Perform bedside cardiac ultrasound immediately during rhythm checks (≤10 seconds interruption) to identify reversible causes and differentiate true PEA from pseudo-PEA with cardiac wall motion 1, 2, 4

The "H's and T's" must be systematically recalled during each 2-minute CPR cycle 1, 2:

Hypovolemia:

• Administer IV/IO crystalloid boluses empirically if suspected 2
• Ultrasound shows collapsed IVC and small, hyperdynamic ventricles 4, 5
• Blood transfusion for severe hemorrhage 2

Hypoxia:

• Ensure adequate oxygenation and ventilation with advanced airway 2
• Lung ultrasound can identify pneumothorax or pulmonary pathology 4

Hydrogen ion (Acidosis):

• Identify and correct metabolic abnormalities 2

Hypo/Hyperkalemia:

• Treat electrolyte abnormalities immediately, particularly hyperkalemia which directly causes cardiac arrest 2

Hypothermia:

• Rewarm if core temperature <35°C 2

Tension Pneumothorax:

• Perform immediate needle decompression at 2nd intercostal space, mid-clavicular line if clinically suspected—do not delay for imaging 2
• Ultrasound shows absent lung sliding and absent B-lines 4

Tamponade (Cardiac):

• Ultrasound has 100% sensitivity for detecting pericardial effusion with tamponade physiology 2
• Perform pericardiocentesis guided by echocardiography 2

Thrombosis (Pulmonary Embolism):

• Consider thrombolysis, surgical embolectomy, or mechanical embolectomy as reasonable emergency treatment for suspected massive PE 3, 1
• Early systemic thrombolysis is associated with improved outcomes compared to use after conventional ACLS failure 1
• Ultrasound shows RV dilation, RV dysfunction, and potentially visible thrombus (100% sensitivity, 97% specificity when performed by experienced personnel) 2, 6

Thrombosis (Coronary - Acute MI):

• Ultrasound can identify regional wall motion abnormalities (86% sensitivity, 94% specificity) 2
• Consider emergent cardiac catheterization if ROSC achieved 1

Toxins:

• Higher epinephrine doses may be indicated for β-blocker or calcium channel blocker overdose 1
• Sodium bicarbonate for sodium channel blocker toxicity (see below) 3

Trauma:

• Ultrasound FAST exam for intra-abdominal hemorrhage 4, 5

Specific Pharmacologic Considerations

Sodium Bicarbonate

Routine use of sodium bicarbonate is NOT recommended for PEA cardiac arrest 3

However, sodium bicarbonate has specific indications:

• Sodium channel blocker toxicity (cocaine, tricyclic antidepressants, local anesthetics): Administer sodium bicarbonate as standard advanced life support with addition for life-threatening dysrhythmias 3
• Severe metabolic acidosis with known cause: In cardiac arrest, rapid IV dose of 44.6-100 mEq (one to two 50 mL vials) may be given initially and continued at 44.6-50 mEq every 5-10 minutes as indicated by arterial pH and blood gas monitoring 7
• Hyperkalemia-induced arrest: May be beneficial as part of hyperkalemia treatment protocol 2

Critical caveat: Bicarbonate solutions are hypertonic and may produce undesirable rise in plasma sodium concentration; however, in cardiac arrest, the risks from acidosis may exceed those of hypernatremia 7

Calcium

Routine administration of calcium for treatment of cardiac arrest is NOT recommended 3

Calcium has specific indications in PEA:

• Hyperkalemia-induced arrest: Calcium chloride or calcium gluconate to stabilize cardiac membrane 2
• Calcium channel blocker toxicity: High-dose calcium administration as part of toxicologic management 3
• Hypocalcemia-induced arrest: Documented severe hypocalcemia 2

Magnesium

Routine magnesium administration is NOT recommended for PEA arrest 3

Magnesium has limited specific indications:

• Documented hypomagnesemia contributing to arrest 2
• Torsades de pointes (though this typically presents as VF/pulseless VT, not PEA) 3

Medications NOT Recommended

• Atropine: Available evidence suggests routine use during PEA is unlikely to have therapeutic benefit 3
• Transcutaneous or epicardial pacing: NOT effective as routine treatment in PEA cardiac arrest, regardless of timing or location 8

Advanced Interventions

Consider venoarterial ECMO (VA-ECMO) early for refractory PEA with suspected reversible cause, as implementation takes time and can be lifesaving for cardiogenic shock or dysrhythmias unresponsive to other measures 3

Critical Pitfalls to Avoid

• Do not delay CPR while searching for causes—continue high-quality compressions with minimal interruptions while systematically evaluating 2
• Do not prolong ultrasound examinations beyond 10 seconds during rhythm checks, as any pause reduces coronary perfusion pressure 2
• Do not rely on physical examination alone—pulse assessment is unreliable and findings are frequently misinterpreted during cardiac arrest 1
• Do not prematurely terminate resuscitation—prolonged efforts are more likely successful in PEA than asystole, particularly in young patients with healthy cardiovascular systems 1
• Do not assume fixed, dilated pupils indicate irreversible brain injury—this is an expected pharmacologic effect of epinephrine administration during CPR 1

Post-ROSC Care

If ROSC is achieved:

• Initiate comprehensive post-cardiac arrest care including consideration of targeted temperature management 1
• Address the underlying cause that precipitated the arrest 1
• Monitor for complications and optimize hemodynamics, oxygenation, and ventilation 3