General Information About Defibrillators

Why Defibrillation?

• Sudden Cardiac Arrest (SCR)-Rapid irregular rhythm causing heart to quiver
• Cause: Ventricular Fibrillation (VF)
  • Can lead to death if emergency shock not delivered
• Defibrillation – to counteract fibrillation

Defibrillator

• Device used to administer an electric current (shock) to the heart
• Types of Defibrillators
  • Manual external
  • Manual Internal
  • Automated External (AED)
  • Semi-Automated External
  • Implantable Cardioverter-Defibrillator (ICD)

Manual External Defibrillator

• Widely used in Hospitals and clinics
• Inbuilt EKG reader
• Clinician Diagnoses the condition and accordingly administers the shock through paddles or pads

Manual Internal Defibrillator

• Exclusively used in Operation Theatres
• Charge delivered through internal paddles in direct contact with the heart

Automated External Defibrillator (AED)

• Used by lay persons requiring little training
• Built in heart rhythm analyzer
• Advices whether shock is required

Semi-Automated External Defibrillators

• Used by paramedics and emergency medical technicians
• Automated capabilities of AED
• With ECG display and manual over ride option

Implantable Cardioverter Defibrillator

• Implants similar to pacemakers
• Constantly monitor heart rhythm
• Automatically administers shock for arrhythmias

Types of waveform – Shape of defibrillation current

• Monophasic damped sine waveform – delivers energy in one direction
  • Relies on adjustment of joule settings
• Biphasic damped sine waveform – bi-directional current flow
  • Measures impedance of patient and delivers precise dose of electricity
  • Uses significantly low energy levels
  • Decreases risk of burn in Myocardial damage