Defibrillation Flashcards
What is defibrillation?
A process in which an electronic device gives an electric shock to the heart
What is voltage?
It is known as electrical potential difference measuring electrical pressure
What is the unit of measurement for voltage?
Joules
1 joule = 1 volt
What is current?
It is the flow of electricity from one region of the circuit to the next
What is the amount of current delivered to the heart dependent on?
The voltage and impedance
What is impedance?
The resistance to the flow of current
When is impedance likely to occur? (5)
A large and/or hairy chest
Breast tissue
Very dry skin
Excess air in the lungs
Improper application of the defib pads
What is Ohm’s Law?
Voltage
Current = ————
Impedance
What are the two types of defibrillation?
Monophasic defibrillation
Biphasic defib
What is monophasic defib?
Where the defib delivers shock to the heart from one vector
What is biphasic defib?
Where the defib delivers a shock to the heart via two vectors
What is peak current?
The highest amount of current delivered to the heart in a single shock.
Too much peak current can result in electroporation (formation of aqueous pores in the cell surface membrane) of the myocardial cells, which may result in myocardial dysfunction
What is electroporation?
Formation of aqueous pores in the cell surface membrane
What is average current?
The mean amount of current delivered to the heart in a single shock.
I’m is believed that this is what is responsible for most successful defib
What does ZOLL RBW stand for?
ZOLL Rectilinear Biphasic Waveform
What is ZOLL RBW?
It starts with the most amount of voltage for any given energy setting and then controls the delivery of current through a series of internal resistors.
This means low impedance patients are not overdosed, while high impedance patients get the most possible current
What are the seven safety checks needed prior to placing pads?
Pacemakers/ICD Patches (GTN) Perspiration (Water) Playtex (Metal underwrites bras) Pendants (Jewellery) Piercings (that come in contact with pads) Shave?
How much joules is needed for the first shock? (According to resuscitation guidelines)
150 joules
Subsequent shocks - comsider increasing the joules if defib allows this
What is the guidelines provided by the ZOLL organisation?
First shock = 120 joules
Second shock = 150 joules
Third shock = 200 joules
Subsequent shocks at 200 joules
