Resuscitation Procedures

Arrhythmias associated with cardiac arrest are divided into two groups: shockable rhythms (VF/VT) and non-shockable rhythms (asystole and PEA). The principle difference in management is the need for attempted defibrillation in patients with VF/VT. Subsequent actions, including chest compression, airway management and ventilation, venous access, administration of adrenaline, and the identification and correction of reversible factors, are common to both groups.

Non-shockable rhythms (PEA and asystole)
Pulseless electrical activity (PEA) is defined as cardiac electrical activity in the absence of any palpable pulse. These patients often have some mechanical myocardial contractions but they are too weak to produce a detectable pulse or blood pressure. PEA may be caused by reversible conditions that can be treated if they are identified and corrected. Asystole refers to a state of no cardiac activity. Survival following cardiac arrest with asystole or PEA is unlikely unless reversible cause can be found and treated effectively.
In asystole, the heart will not respond to defibrillation because it is already depolarized while in PEA, the heart is very unlikely to be shocked successfully into a perfusing rhythm and delivering repeated shocks will increase myocardial injury, both directly from the electric current and indirectly from the interruptions in coronary blood flow.


Sequence of actions for PEA
• Start CPR.
• Give adrenaline as soon as intravascular access is achieved.
• Continue CPR until the airway is secured, then continue chest compressions without pausing during ventilation.
• Recheck the rhythm after 2 min.
o If there is no change in the ECG appearance:
• Continue CPR.
• Recheck the rhythm after 2 min and proceed accordingly.
• Give further adrenaline every 3-5 min.
o If the ECG changes and organized electrical activity is seen, check for a pulse.
• If a pulse is present, start post-resuscitation care.
• If no pulse is present:
O Continue CPR.
o Recheck the rhythm after 2 min and proceed accordingly.
o Give further adrenaline every 3-5 min

Shockable rhythms (VF/VT)
VF refers to ventricular fibrillation with the presence of a pulse and VT refers to ventricular tachycardia.

Sequence of actions
• Attempt defibrillation
• Immediately resume chest compressions without reassessing the rhythm or feeling for a pulse.
• Continue CPR for 2 min, then pause briefly to check the monitor:
o If VF/VT persists:
• Give a further (2nd) shock
• Resume CPR immediately and continue for 2 min.
• Pause briefly to check the monitor.
• If VF/VT persists give adrenaline IV followed immediately by a (3rd) shock
• Resume CPR immediately and continue for 2 min.
• Pause briefly to check the monitor.
• If VF/VT persists give amiodarone (anti-arrhythmic drug) IV followed immediately by a (4th) shock
• Resume CPR immediately and continue for 2 min.
• Give adrenaline IV immediately before alternate shocks (i.e. approximately every 3-5 min).
• Give a further shock after each 2 min period of CPR and after confirming that VF/VT persists.
o If organised electrical activity is seen during this brief pause in compressions, check for a pulse.
• If a pulse is present, start post-resuscitation care.
• If no pulse is present, continue CPR and switch to the nonshockable algorithm.
o If asystole is seen, continue CPR and switch to the nonshockable algorithm.

Potentially reversible causes
Potential causes or aggravating factors for which specific treatment exists must be sought during any cardiac arrest. For ease of memory, these are divided into two groups of four, based upon their initial letter, either H or T:
• Hypoxia
• Hypovolaemia
• Hyperkalaemia, hypokalaemia, hypocalcaemia, acidaemia, and other
metabolic disorders
• Hypothermia
• Tension pneumothorax
• Tamponade (fluid in the pericardial sac)
• Toxic substances
• Thromboembolism (pulmonary embolus/coronary thrombosis)

Signs of life
If signs of life (such as regular respiratory effort or movement) reappear during CPR, or readings from the patient’s monitors (e.g. exhaled carbon dioxide or arterial blood pressure) are compatible with a return of spontaneous circulation, stop CPR and check the monitors briefly. If an organized cardiac rhythm is present, check for a pulse. If a pulse is palpable, continue post-resuscitation care. If no pulse is present, continue CPR.

Contributed by John Lee