pulseless electrical activity (PEA)

see also:

• cardiology
• choking / respiratory arrest / cardiac arrest / BLS / ALS / CPR
• also called Electro-Mechanical Dissociation (EMD)
• paediatric resus. drugs
• RCH guideline - paediatric cardiac arrest algorithm

• It appears that rapid elevations in pulmonary pressures (due to pulmonary vascular bed compression such as in mucus plug and massive aspiration, and acute hypoxic vasoconstriction) and resultant RV failure may cause PEA in respiratory failure and this may be evident on the ECG in almost half of cases of PEA/cardiac arrest without pre-existing RVH with a median time of around 4-5 minutes prior to arrest¹⁾
  • ECG pattern of Right Ventricular Strain (RVS) that the researchers found associated with this impending arrest:
    • V1 RVS pattern change sequence of:
      • notable increase in ST elevation
      • a notch in the S wave with associated decrease in S wave amplitude (20 minutes pre-arrest)
      • notch becomes progressively later in the QRS complex and gradually grows into a terminal R wave reflecting delayed RV activation which is progressive RV conduction delay with widening of the terminal R wave as the patient gets closer to PEA arrest.
    • plus, no intraventricular conduction delay or terminal intraventricular conduction delay (i.e. not delay in the intrinsicoid deflection)
    • plus, 2 or more of the following:
      • ST elevation in V1
      • Rightward directed ST elevation vector in limb leads (i.e. towards lead III)
      • Rightward axis deviation in limb leads
    • simultaneous development of the S1Q3T3 pattern and peaked T waves may also occur

Time access at the bottom is time BEFORE cardiac arrest

• Hypovolaemia
• Hypoxia
• Hydrogen ion - severe acidosis
• Hypokalaemia or Hyperkalaemia
• Hypoglycaemia
• Hypothermia

• Toxins - drug overdose
• Tamponade - cardiac
• Tension pneumothorax
• Thrombosis - pulmonary embolism or coronary AMI
• Trauma

• 4 chamber view of heart:
  • collapsed RV with pericardial effusion ⇒ cardiac tamponade
  • flat RV and flat LV ⇒ hypovolaemia
  • flat RV and hyperdynamic LV ⇒ mechanical hyperinflation
  • enlarged RV and RA + flat LV ⇒ massive pulmonary embolism
• check lungs:
  • sliding sign absent + no comet tails ⇒ pneumothorax
  • normal then other causes to consider:
    • electrolyte imbalance
    • drugs and toxins
    • hypothermia
    • cardiogenic shock eg. AMI