What are the types of SCA and their management?

Types of Sudden Cardiac Arrest (SCA) and Their Management

Ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT) are the most common types of SCA requiring immediate defibrillation, while asystole and pulseless electrical activity require high-quality CPR as the primary intervention. 1

Types of SCA

SCA can present with different cardiac rhythms, each requiring specific management:

1. Shockable Rhythms:

   • Ventricular Fibrillation (VF): Most frequent initial rhythm in witnessed out-of-hospital SCA
   • Pulseless Ventricular Tachycardia (VT): Requires similar management to VF

2. Non-Shockable Rhythms:

   • Asystole: Absence of electrical activity
   • Pulseless Electrical Activity (PEA): Electrical activity without detectable pulse

Management Algorithm for SCA

1. Recognition of SCA

• Assume SCA in any collapsed and unresponsive person
• Be aware that seizure-like activity and abnormal breathing/gasping can be signs of SCA 1
• Do not waste time checking for pulse if untrained

2. Immediate Response

• Activate emergency response system immediately
• Begin high-quality CPR:
  • Push hard (at least 2 inches/5 cm depth)
  • Push fast (100-120 compressions per minute)
  • Allow complete chest recoil
  • Minimize interruptions in compressions
• Retrieve AED/defibrillator as quickly as possible 1

3. Rhythm-Specific Management

For Shockable Rhythms (VF/VT):

• Apply AED/defibrillator as soon as possible while continuing CPR
• Stop CPR only for rhythm analysis and shock delivery
• If shock indicated, deliver shock immediately
• Resume CPR immediately after shock for 2 minutes before next rhythm check
• For every minute defibrillation is delayed without CPR, survival decreases by 7-10%
• With bystander CPR, survival decreases more gradually at 3-4% per minute 1

For Non-Shockable Rhythms (Asystole/PEA):

• Continue high-quality CPR
• Check rhythm every 2 minutes
• Search for and treat reversible causes

4. Post-Resuscitation Care

• Upon return of spontaneous circulation (ROSC), consider rapid cooling (induced hypothermia) for VF arrest victims who remain comatose 1
• Transport to a hospital capable of advanced cardiac life support
• Continue effective CPR during transport if ROSC not achieved 1

Critical Factors Affecting Survival

1. Time to CPR: Immediate CPR can double or triple survival rates 1
2. Time to Defibrillation: The single greatest factor affecting survival
   • Survival rates >60% possible in young athletes with prompt CPR and defibrillation 1
3. CPR Quality: Proper depth, rate, and minimal interruptions
4. Post-Resuscitation Care: Including targeted temperature management

Special Considerations

• Wet/Sweaty Patients: Use a towel to dry the chest before AED pad placement
• Excessive Chest Hair: May require shaving for proper pad contact 1
• Transport Decisions: Initial CPR and defibrillation should occur at the location of collapse
• Cervical Spine Precautions: Take appropriate precautions when moving the patient, but prioritize effective CPR 1

Common Pitfalls to Avoid

1. Delayed Recognition: Mistaking SCA for seizure or assuming normal breathing when agonal gasping is present 1
2. Delayed Defibrillation: Not retrieving or applying AED quickly enough
3. Poor-Quality CPR: Inadequate depth, excessive interruptions, or slow rate
4. Premature Transport: Moving patient before establishing effective CPR and delivering initial shocks
5. Ineffective CPR During Transport: CPR quality often deteriorates during movement 1

Remember that early recognition, immediate high-quality CPR, and early defibrillation form the cornerstone of successful SCA management, with survival rates decreasing significantly for every minute of delay.