Overview

This section is only a brief summary of the Resuscitation Council’s guidelines. Please refer to their content for more detail.

Cardiac Arrest Rhythms

Shockable rhythms

Ventricular fibrillation (VF):

  • Ventricular muscle fibres contract randomly and cause complete failure of ventricular function

Figure 1: An ECG showing ventricular fibrillation

Ventricular tachycardia (VT):

  • Broad-complex tachycardia originating from the ventricles

Figure 2: An ECG showing ventricular tachycardia

Non-shockable rhythms

Pulseless electrical activity:

  • ECG shows electrical activity (except VF and VT), but no pulse is present

Asystole:

  • Absence of electrical activity on an ECG

Figure 3: An ECG showing asystole

Initial Management

All patients who are unresponsive and not breathing properly

  • Call the resuscitation team/ambulance
  • Commence CPR at a ratio of 30 compressions:2 breaths (30:2)
  • Attach the defibrillator/monitor and assess rhythm
  • Obtain IV access
    • If this isn’t possible, deliver drugs through the intraosseous (IO) route
  • Throughout, think of the causes of cardiac arrest:
    • The Hs:
    • The Ts:
      • Thrombosis – coronary or pulmonary
        • IV alteplase should be considered but these may take up to 90 minutes to work so CPR should be extended up to 90 minutes.
        • A PCI may need to be considered
      • Tension pneumothorax
      • Tamponade (cardiac)
      • Toxins 
  • Management then varies depending on the underlying rhythm

If shockable (VF/VT)

  • If “witnessed” cardiac arrest i.e. in a coronary care unit: 3 stacked shocks then 2 minutes CPR then check rhythm then give single shocks instead and repeat
  • If not witnessed: 1 single shock then 2 minutes CPR then check rhythm then repeat
  • After third shock: adrenaline 1mg and amiodarone 300mg
    • Repeat adrenaline 1mg every 3-5 minutes i.e. during alternate cycles of CPR
  • After fifth shock: further 150mg dose of amiodarone
    • Use lidocaine if amiodarone is not available

If non-shockable (asystole/PEA)

  • Adrenaline 1mg as soon as possible followed by CPR then check rhythm
    • Repeat adrenaline 1mg every 3-5 minutes i.e. during alternate cycles of CPR

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