Document Detail

Biphasic shocks compared with monophasic damped sine wave shocks for direct ventricular defibrillation during open heart surgery.
MedLine Citation:
PMID:  12717126     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Biphasic waveform shocks are more effective than monophasic shocks for transchest ventricular defibrillation, atrial cardioversion, and defibrillation with implantable defibrillators but have not been studied for open chest, intraoperative defibrillation. This prospective, blinded, randomized clinical study compares biphasic and monophasic shock effectiveness and establishes intraoperative energy dose-response curves. METHODS: Patients undergoing cardiothoracic surgery with bypass cardioplegia were randomly assigned to the monophasic or biphasic shock group. Ventricular fibrillation occurring after aortic clamp removal was treated with escalating energies of 2, 5, 7, 10, and 20 J until defibrillation occurred. If ventricular fibrillation persisted, a 20-J crossover shock of the other waveform was used. RESULTS: Cumulative defibrillation success at 5 J, the primary end point of the study, was higher in the biphasic group than in the monophasic group (25 of 50 vs. 9 of 41 defibrillated; P = 0.011). In addition, the biphasic group required lower threshold energy (6.8 vs. 11.0 J; P = 0.003), less cumulative energy (12.6 vs. 23.4 J; P = 0.002), and fewer shocks (2.5 vs. 3.5; P = 0.002). Crossover-shock effectiveness did not differ between groups. Dose-response curves show biphasic shocks to have higher cumulative success rates at all energies tested. CONCLUSIONS: Biphasic shocks are substantially more effective than monophasic shocks for direct defibrillation. The dose-response curve guides selection of first-shock energy for traditional step-up protocols. Starting at 5 J optimizes for lowest threshold and cumulative energy, whereas 10 or 20 J optimizes for more rapid defibrillation and fewer shocks.
Birgit Schwarz; T Andrew Bowdle; G Kimble Jett; Peter Mair; Karl H Lindner; Gabriel S Aldea; Robert G Lazzara; Sharon G O'Grady; Paul W Schmitt; Robert G Walker; Fred W Chapman; Willis A Tacker
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Publication Detail:
Type:  Clinical Trial; Journal Article; Multicenter Study; Randomized Controlled Trial; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Anesthesiology     Volume:  98     ISSN:  0003-3022     ISO Abbreviation:  Anesthesiology     Publication Date:  2003 May 
Date Detail:
Created Date:  2003-04-28     Completed Date:  2003-07-22     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  1300217     Medline TA:  Anesthesiology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1063-9     Citation Subset:  AIM; IM    
Department of Anesthesiology and Critical Care Medicine, University of Innsbruck, Austria.
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MeSH Terms
Cardiac Surgical Procedures
Coronary Artery Bypass / methods*
Echocardiography, Transesophageal
Electric Countershock* / methods
Electrolytes / blood
Middle Aged
Monitoring, Intraoperative
Oxygen / blood
Partial Pressure
Prospective Studies
Ventricular Fibrillation / surgery*
Reg. No./Substance:
0/Electrolytes; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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