Defibrillation

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  • 1849: Written history of fibrillation and defibrillation goes back to the pioneering work of Carl Ludwig’s laboratory. In 1849, Ludwig’s student M. Hoffa was the first to witness and, most importantly, to document the onset of ventricular fibrillation, which he induced by electrical stimulus. This picture from their paper shows rapid contractions produced by electrical stimulation, which resulted in cardiac arrest.
  • 1899: Further experiments with “faradization” of the heart were conducted by two physiologists from University of Geneva, Switzerland, J.-L. Prevost and F. Batelli. They discovered that, 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. This discovery was made in 1899. Unfortunately, unlike discovery of contemporary electrocardiogram, defibrillation did not enjoy similar attention and success. They did this using dogs!
  • Work of Carl J. Wiggers in the Department of Physiology of Western Reserve University was well known to the thoracic surgeon Claude S. Beck from the University Hospitals in Cleveland, which are adjacent to the Western Reserve University. In 1947, Dr. Beck successfully applied defibrillation therapy and saved the first human life by this method (C.S. Beck, W.H. Pritchard, H.S. Feil, Ventricular fibrillation of long duration abolished by electric shock. Jour. Amer. Med. Assoc. 135: 985, 1947). His success triggered the immediate acceptance of this method by the clinical community and started a wide front of basic and clinical research of fibrillation and defibrillation.
  • Work of Carl J. Wiggers in the Department of Physiology of Western Reserve University was well known to the thoracic surgeon Claude S. Beck from the University Hospitals in Cleveland, which are adjacent to the Western Reserve University. In 1947, Dr. Beck successfully applied defibrillation therapy and saved the first human life by this method (C.S. Beck, W.H. Pritchard, H.S. Feil, Ventricular fibrillation of long duration abolished by electric shock. Jour. Amer. Med. Assoc. 135: 985, 1947). His success triggered the immediate acceptance of this method by the clinical community and started a wide front of basic and clinical research of fibrillation and defibrillation.
  • Peak current should be less then 30Ohms
  • Defibrillation

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

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