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defibrillation (electrical cardioversion, automated external difibrillation, AED)

Indications: 1) termination of life-threatening ventricular arrhythmias - ventricular tachycardia (VT) - ventricular fibrillation/flutter (VF) 2) termination of supraventricular tachyarrhythmias a) hemodynamic compromise b) atrial fibrillation/atrial flutter refractory to carotid sinus massage or chemical cardioversion c) if atrial fibrillation/atrial flutter is known to be of < 48 hours in duration, attempt synchronized cardioversion d) patients without hemodynamic compromise for which atrial fibrillation or atrial flutter may be of > 48 hours in duration should be anticoagulated for 3 weeks prior to cardioversion - anticoagulation should be continued for 3 weeks after cardioversion e) synchronized cardioversion - begin 50 joules - then 100, 200, 300, 360 joules Contraindications: - atrial fibrillation with digitalis toxicity toxicity should be alleviated before cardioversion/ defibrillation Benefit/risk: - number needed to treat (NNT) - rapid defibrillation after cardiac arrest - 2.5 to prevent 1 death [5] - no identified harm Procedure: Protocol: automated external defibrillator Also see protocol for manual defibrillators 1) turn on defibrillator 2) attach to victim a) select correct pad size for victim's size & age b) open package, expose adhesive surface & attach to victim upper right sternal border & cardiac apex c) attach directly to chest wall, do NOT defibrillate through clothing d) attach cables if needed 3) analysis, place in analysis mode a) announce 'Analyzing rhythm - stand clear' b) verify 1] no victim movement 2] no one in contact with victim c) analyze, press analyze (some AEDs omit this control) 4) shock a) if VF/VT is present, AED will charge to 150-360J b) announce 'shock is indicated - stand clear' c) verify no one is touching victim d) apply 25 lbs of pressure on both paddles e) press 'shock' button' 5) resume CPR after shock a) continue CPR for 2 minutes prior to analyzing rhythm b) cycles of 2 minutes of CPR, analyze rhythm, shock if rhythm is shockable c) repeat cycle of 2 minutes after shock until VF/VT no longer present Notes: Other considerations: 1) unconscious adults with return of spontaneous circulation after out-of-hospital cardiac arrest be cooled to 32 to 34 Celsius for 12 to 24 hours when the initial rhythm was ventricular fibrillation [2]

Related

'quick-look' paddle protocol for manual defibrillators

General

cardioversion

References

  1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 238-40
  2. ECC Committee, ECC Subcommittees, and ECC Task Forces; and Authors of Final Evidence Evaluation Worksheets 2005 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care With Treatment Recommendations Conference. Circulation. 2005 Dec 13;112(24_suppl):b2-b5. No abstract available. PMID: 16344388
  3. ACLS - The Reference Texbook ACLS: Principles & Practice, Cummins RO et al (eds), American Heart Association, 2003 ISBN 0-87493-341-2
  4. Medical Knowledge Self Assessment Program (MKSAP) 16, American College of Physicians, Philadelphia 2012
  5. The NNT: Rapid Defibrillation for Cardiac Arrest. http://www.thennt.com/nnt/defibrillation-for-cardiac-arrest/