How much does an AV defib weigh?
Under 25kg
What is a Joule?
- one amp of current
- passed through 1 ohm of resistance
- for one second
What is the formula for Energy in Joules?
Voltage X Current X Time
How is current expressed?
Voltage/ impedence
Current is what defibs the heart
What is impedance?
Resistance to flow of current
What can Impedance be impacted by?
- Patients Body mass
- patients body composition
- temperature
- Diaphoresis
- Quality of contact with the pads
What is Monophasic defibrilation?
shock delivered to heart over one vector
- no ability to adjust for impedance
What is the joules delivered through monophasic defib?
360 joules in all adult patients
How many joules are delivered to a paed with monophasic defib?
4 J/kg
What is biphasic defib?
where waveform where shock is delievered to heart via 2 vectors… in a loop sort of
Why is biphasic good for VF?
Shown to allow termination of VF at lower current than monophasic
Why is biphasic better than monophasic?
- less conduction abnormalities and damage to the heart
- Less energy required
- > which means smaller battery, smaller unit, less charging time -> quicker to defib
Advantages of AED
- analyses patient for you
- decided whether shockable rhythm
- provides step by step instructions
Disadvantages of AED
- increased hands of chest time
- decreases interthoracic pressure
- can analyse rhythm incorrectly based on criteria used
- criteria may not match AV’s guidelines
What are the advantages of Manual mode on the defib
- allows you to select joules
- > 200 J for adults
- > 4j/kg for paeds
- allows user to analyse rhythm of the patient
- Can be quicker than auto mode - less hand of chest time
What are the advantages of Manual mode on the defib
- Difficult decisions could take longer
- to diagnose slow VT it needs to be printed
- sometimes can look like asystole when its fine VF
Where do defib pads get placed?
Lateral - Left Mid auxilliary line - 6th IC space
Anterior - Right parasternal area over 2nd IC space. Between nipple and clavicle
How long should a ventilation in high performance CPR last?
1 second per ventilation
What does COACHED stand for in cognitive first aid emergency defib?
Continuous compressions Oxygen away All others away Charging Hands off Evaluate Rhythm Defib or disarm
What is the interpretation criteria for VF?
- Ventricular rate - Nil discernable
- Ventricular Rhythm - Bizzare, chaotic, amplitude >0.1mV
- P waves - Nil discernable
- PR interval - Nil discernable
- QRS duration - nil discernable
What is the interpretation criteria for VT?
Ventricular rate - >100
Ventricular rhythm - Regular
P waves - not associated or nil discernable
- PR interval - nil discernable
- QRS duration - >0.12
