Cardiac Arrest

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Introduction

Ventricular fibrillation is an emergency, representing the loss of coordinated contraction of the ventricles. A rapid loss of cardiac output will result in death if it is not quickly reversed by defibrillation. VF can be caused by ventricular tachycardia on top of electrolyte imbalances, hypoxemia, or acidosis. Reentry circuits are thought to break up into smaller wavelets which wander throughout the ventricles.

 

 

The Case of...

a simple case introducing clincial presentation and calling for a differential diagnosis to get students thinking.

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Causes and Risk Factors

6 H's and 5 T's

• hypoxia
• hypovolemia
• hyperkalemia
• hypokalemia
• hypoglycemia
• hypothermia
• hydrogen ions (acidosis)

• tension pneumothorax
• tamponade
• toxins/therapeutics
• thromboembolism
• trauma

 

 

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Pathophysiology

The most common initial rhythms in witnessed sudden cardiac arrest are

• pulseless ventricular tachycardia
• ventricular fibrillation
• unstable tachydysrhythmia

VF or rapid, pulseless VT, which rapidly detiorates into VF. VF will become asystole if untreated.

 

 

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Signs and Symptoms

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Investigations

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Differential Diagnosis

 

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Treatments

The interval from collapse to defibrillation, the only effective treatment for VF, is one of the most critical determinants of survival.

CPR cannot directly restore an organized rhythm, but does provide a small amount of blood flow to the brain and heart.

For every minute that passes, survival declines by 7-10% per minute, or by 3-4% per minute if CPR is provided.

 

Basic life support (BLS) describes first aid CPR.

 

Automatic external defibrillation (AED) can be used with minimal training.

 

Advanced cardiac life support (ACLS) is the definitive treatment for cardiac arrest.

Ensure large-bore IV access is in place.

 

 

Breaking bad news

 

 

Ethical Issues

terminating rescutative efforts

substitute decision-makers

advance care directives and decision-making capacity

 

 

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Consequences and Course

 

 

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The Case of...

Case #2 - a small story wrapping it all up and asking especially about management.

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Additional Resources

 

 

 

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Topic Development

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