8. Defibrillation and cardioversion

Question 1

What is the goal of depolarisation?

Answer 1

To return organised spontaneous electrical activity to the heart

Question 2

What factors determine thoracic impedence?

Answer 2

Pad size
Chest thickness
interface between pads and skin
positioning of pads on chest wall

Question 3

Where should chest pads for shocking be applied on an infant?

Answer 3

Anterior - posterior position

Question 4

Where should chest pads for shocking be applied on a child?

Answer 4

Anterior - lateral position

Question 5

When using a manual defibrillator what energy dose should be used?

Answer 5

4 Joules per kg (but in large children do not exceed adult doses)

Question 6

What is the max time you can pause chest compressions to do rhythm check?

Answer 6

No more than 5 seconds

Question 7

What are the only occasions when resuscitations efforts would stop?

Answer 7

If resuscitator exhausted
child shows signs of life
help arrives and takes over management

Question 8

What is the difference between defibrillation and cardioversion?

Answer 8

Defibrillation = delivering electrical current asynchronously when there is no cardiac output (VF/pVT)
Cardioversion = delivering synchronised current in time with the R wave when there is an output (SVT/VT) -> you need sedation and anaesthesia before synchronised shock

Question 9

What energy level is used for synchronised shock (cardioversion)

Answer 9

Initially 1 Joule / kg

Then can be increased to 2 Joules/kg if the arrhythmia persists