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Cardiac Arrest

Resuscitation Council UK Adult Advanced Life Support Guidelines (2021)

Background Information

Shockable rhythm:
  • Pulseless ventricular tachycardia (pVT)
  • Ventricular fibrillation (VF)

Non-shockable rhythm:
  • Asystole
  • Pulseless electrical activity (PEA)

4Hs and 4Ts
  • Hypoxia
  • Hypovolaemia
  • Hyperkalaemia (hypokalaemia, hypoglycaemia, hypocalcaemia, acidaemia and other metabolic disorders0
  • Hypothermia
 
  • Tension pneumothorax
  • Tamponade (cardiac)
  • Toxins
  • Thrombosis (coronary thrombosis or pulmonary embolism)

Resuscitation council adult BLS guidelines:
  • Start CPR in any unresponsive person with absent or abnormal breathing
  • Slow, laboured breathing (agonal breathing) should be considered a sign of cardiac arrest

Guidelines

  • Call for help (“Cardiac Arrest Call” telephone number: 2222)
  • Start CPR immediately

The following things should be carried out simultaneously by the resuscitation team:
  • Attach defibrillator and assess rhythm
  • Gain IV access, if not possible IO access
  • Airway management
  • High flow oxygen via bag valve mask ventilation

Subsequent management depends on whether the rhythm is shockable or non-shockable.
 

Adrenaline is only given after 3rd shock / cycle.

  • Once adrenaline has been given, repeat every 3-5 minutes or alternating cycles (i.e. after 3rd, 5th, 7th, 9th shock and so on…)


Amiodarone is only given twice maximum throughout the ALS, after 3rd and 5th shock. (300mg and 150mg respectively)

  • Unlike adrenaline, amiodarone should not be repeated further after twice

Once a shockable rhythm identified on monitor / defibrillator
  1. Deliver 1 shock (1st shock)
  2. No drugs given here
  3. Resume CPR immediately for 2 minutes
  4. After 2 minutes, pause for <5 sec to reassess the rhythm

Shockable rhythm persists (2nd cycle)
  1. Deliver 1 shock (2nd shock)
  2. No drugs given here
  3. Resume CPR immediately for 2 minutes
  4. After 2 minutes, pause for <5 sec to reassess the rhythm 

Shockable rhythm persists (3rd cycle)
  1. Deliver 1 shock (3rd shock)
  2. Resume CPR immediately for 2 minutes AND administer 1mg of 1:10,000 adrenaline and 300mg of amiodarone
  3. After 2 minutes, pause for <5 sec to reassess the rhythm 
  4. Shockable rhythm persists

Shockable rhythm persists (4th cycle)
  1. Deliver 1 shock (4th shock)
  2. No drugs given here
  3. Resume CPR immediately for 2 minutes
  4. After 2 minutes, pause for <5 sec to reassess the rhythm 

Shockable rhythm persists (5th cycle)
  1. Deliver 1 shock (5th shock)
  2. Resume CPR immediately for 2 minutes AND administer 1mg of 1:10,000 adrenaline AND 150 mg of amiodarone AND consider 50mg of lidocaine
  3. After 2 minutes, pause for <5 sec to reassess the rhythm 
  4. Shockable rhythm persists
 

If there is a combination of clinical and physiological signs of ROSC such as waking, purposeful movement, arterial waveform or sharp rise in ETCO2, consider stopping chest compressions for rhythm analysis, and if appropriate a pulse check.

Once a non-shockable rhythm is identified, adrenaline is given immediately; no other drugs are given.

  • Once adrenaline has been given, repeat every 3-5 minutes or alternating cycles (i.e. after 3rd, 5th, 7th shock and so on…)


As suggested in its name, do not give shocks (i.e. defibrillation) in non-shockable rhythms

Non-shockable rhythm identified on monitor / defibrillator
  • Resume CPR immediately for 2 minutes AND administer 1mg of 1:10,000 adrenaline
  • After 2 minutes, pause for <5sec to reassess the rhythm
  
Shockable rhythm persists: (2nd cycle)
  • Resume CPR immediately for 2 minutes
  • No drugs given here
  • After 2 minutes, pause for <5sec to reassess the rhythm

Shockable rhythm persists: (3rd cycle)
  • Resume CPR immediately for 2 minutes AND administer 1mg of 1:10,000 adrenaline
  • After 2 minutes, pause for <5sec to reassess the rhythm


Down the line, adrenaline will be given in the 5th cycle, 7th cycle and so on...

 

If there is a combination of clinical and physiological signs of ROSC such as waking, purposeful movement, arterial waveform or sharp rise in ETCO2, consider stopping chest compressions for rhythm analysis, and if appropriate a pulse check.

CPR is made up of:
  • Chest compression
    • Depth: 5-6 cm (adults), 5 cm (children), 4 cm (infant)
    • Rate: 100-120 compressions/min (across all age)
 
  • Rescue breaths
    • If trained → 2 rescue breaths after every 30 compressions (compression: rescue breaths ratio = 30:2) (Ratio may chance if a supraglottic airway or definitive airway is in situ, see below)
    • If unable or unwilling to do so → give continuous chest compression

Antero-lateral pad position is the position of choice for initial pad placement. 
  • First pad: below the right clavicle, next to the sternum
  • Apical (lateral) pad position: mid-axillary line, level with V6 ECG electrode position or female breast (i.e. below the armpit) 
  • Click to view alternative positions.

Continue chest compression when:
  • The defibrillator is being retrieved
  • Pads are being applied
  • The defibrillator is charging
 
  • Aim a < 5 seconds interruption in chest compression during the pre-shock and post-shock pause
  • Immediately resume chest compressions after shock delivery

  • If shockable rhythm identified on monitor, give a single shock and resume the 2-minute chest compression cycle
  • Three-stacked shocks may be considered if a shockable rhythm occurs during a witnessed, monitored cardiac arrest with a defibrillator immediately available (e.g. during cardiac catheterisation or in a high-dependency area)
  • Initial shock energy level: 120-360 J. Increase energy level for subsequent shocks using a fixed or escalating strategy up to maximum output of the defibrillator

  • To minimise risk of fire:
    • Take off all oxygen delivery devices and place ≥ 1 m away from the patient’s chest
    • Ventilator circuits should remain attached 
  • If the patient has an implantable device: place the pad > 8 cm away from the device or use an alternative pad position.
  • During manual chest compressions, ‘hands-on’ defibrillation, even when wearing clinical gloves, is a risk to the rescuer. (check what this means)

During CPR, start with basic airway techniques and progress stepwise according to the skills of the rescuer. Hierarchy of airway techniques:
 
Basic airway manoeuvres
  • Head tilt-chin lift
  • Jaw-thrust
Airway adjuncts
  • Oropharyngeal airway
  • Nasopharyngeal airway
Supraglottic airways (SGA)
  • Laryngeal mask airway
  • i-gel®
Definitive airway
  • Endotracheal tube (ETT)
  • Tracheostomy


If ETT is indicated:

  • Only rescuers with a high tracheal intubation success rate should use tracheal intubation
  • Aim for < 5 second interruption in chest compression for tracheal intubation.
  • Use waveform capnography to confirm tracheal tube position.

  • Give the highest feasible inspired oxygen during CPR
  • Give each breath over 1 sec to achieve a visible chest rise
 
Ventilation when a ETT or SGA is placed:
  • Ventilate at a rate of 10 breaths/min (i.e. 1 breath every 6 sec) 
  • Continue chest compressions without pausing during ventilations
  • With a SGA, if gas leakage results in inadequate ventilation, pause compressions for ventilation using a compression-ventilation ratio of 30:2

Vascular access
  • First attempt IV access to enable drug delivery
  • If unfeasible or unsuccessful → consider IO access
 

Adrenaline dose in ALS: 1mg (10mL of 1 in 10,000)

Give adrenaline in:
  • Non-shockable rhythm: immediately once identified
  • Shockable rhythm: after the 3rd shock

Once adrenaline has been given, repeat every 3-5 minutes or at alternative cycles whilst ALS continues (this applies to both shockable and non-shockable rhythms)

Amiodarone: class III antiarrhythmic (potassium channel inhibitor).

Both amiodarone and lidocaine is only given in a shockable rhythm:
  • Amiodarone:
    • 300 mg IV (IO) after the 3rd shock for patients in a shockable rhythm
    • 150 mg IV (IO) after the 5th shock for patients in a shockable rhythm
 
  • Lidocaine:
    • 100 mg IV (IO) may be used as an alternative to amiodarone
    • An additional bolus of lidocaine 50 mg IV (IO) can also be given after the 5th shock if patient is in a shockable rhythm
 
 

Unlike adrenaline, that is repeated indefinitely every 3-5 minutes / or at alternating cycles. Amiodarone is only given twice maximum in patients in a shockable rhythm, such that after the 7th shock, 9th shock... amiodarone should not be given.

Thrombolytic drugs are tissue plasminogen activators, examples include alteplase.
  • Consider when pulmonary embolus is the suspected or confirmed as the cause of cardiac arrest.
  • Continue CPR for extra 60-90 minutes after administration of thrombolytic drugs.

IV (IO) fluids should only be given where the cardiac arrest is caused by hypovolaemia.

References

Author: Adams Lau
Reviewer:
Last edited: 28/07/25