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Defibrillation:Defibrillation: Advanced Cardiac Life Support 2006
Jamie Ranse
Registered Nurse
Emergency Department
The Canberra Hospital
Overview
• History• Chain of Survival• Indications• How it works• Safety
History
• 1849: Ludwigg and Hoffa – VF induced by electrical stimuli
History
• 1899: Prevost and Batelli - while a weak stimulus can produce fibrillation, a stimulus of higher strength applied to the heart could arrest ventricular fibrillation and restore normal sinus rhythm.
History
• 1947: First defibrillation on humans
History
• 1966: Belfast Ambulance transported physicians performed first pre-hospital defibrillation.
• 1969: First pre-hospital defibrillation by non physicians.
• 1970’s: Diack, Wellborn and Rullman developed first AED’s.
Chain of Survival
• Early Recognition and Assessment
• Early Access
• Early CPR
• Early Defibrillation
• Early Advanced Cardiac Life Support
Chain of Survival
Sudden cardiac arrest survival rate:
• Pre-Hospital: 10%• In-Hopsital: 10%
Indications
• Pulseless VT
• VF
How does it work?
• Electronic counter-shock between to paddles or pads
• Depolarises all cardiac cells and interrupts arrhythmia
• Allows SA node to recommence its dominant role
Defibrillation is the most time critical intervention in a patient with a
shockable rhythms
How does it work?
Thoracic Impedance• Impedance is the natural resistance to the flow of
electrical current, measured in Ohms.• Impedance is determined by a number of factors,
such as:– Underlying structures and pathology– Paddle or adhesive pad position
How does it work?
Monophasic Defibrillation• Delivers ‘shock’ in one phase• Adult: 200J, 300J, 360J, all subsequent shocks
at 360J• Child: 2J/Kg, 2J/Kg, 4J/Kg, all subsequent
shocks at 4J/Kg
How does it work?
Biphasic Defibrillation• Two phases to the delivery of the ‘shock’• Adjusts ‘shock’ according to thoracic impedance• Adult: 150J, 150J, 150J• Child: 1– 2J/Kg
How does it work?
Monophasic v Biphasic Defibrillation• Peak current decreased resulting in less
myocardial damage
How does it work?
Semi-Automatic External Defibrillation• Primarily used by laypersons in the pre-hospital
setting• Survival rate increased to ~ 70% pre-hospital
and 80% in-hospital• Considered BLS
“audible and visual prompt to
discharge the defibrillator and
deliver a shock when it
recognises a shockable rhythm”
Transcutaneous Pacing
• Early asystole with reversible cause• Attach adhesive pad anterior / posterior• Set rate• Set Milliamps until capture is achieved
Transcutaneous Pacing
• Temporary • Consider other pacing options• Sedate patient
Safety
General Safety
• Yourself, other staff– Dry surface area– Oxygen
• Chest wall– GTN patch– Jewellery– Paddles / Pads not touching
• Technique– One Person– Two Person– Adhesive Pads
Safety
Operator Safety• Assertive• Announce:
– CHARGING, – ALL CLEAR / STAND CLEAR (Visual Check of Area), – SHOCKING
• Check rhythm• Discharge Shock• Continue as per algorithm
Questions