Document Detail


Out-of-hospital cardiac arrest rectilinear biphasic to monophasic damped sine defibrillation waveforms with advanced life support intervention trial (ORBIT).
MedLine Citation:
PMID:  15992986     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Although biphasic defibrillation waveforms appear to be superior to monophasic waveforms in terminating VF, their relative benefits in out-of-hospital resuscitation are incompletely understood. Prior comparisons of defibrillation waveform efficacy in out-of-hospital cardiac arrest (OHCA) are confined to patients presenting in a shockable rhythm and resuscitated by first responder (basic life support). This effectiveness study compared monophasic and biphasic defibrillation waveform for conversion of ventricular arrhythmias in all OHCA treated with advance life support (ALS). METHODS AND RESULTS: This prospective randomized controlled trial compared the rectilinear biphasic (RLB) waveform with the monophasic damped sine (MDS) waveform, using step-up energy levels. The study enrolled OHCA patients requiring at least one shock delivered by ALS providers, regardless of initial presenting rhythm. Shock success was defined as conversion at 5s to organized rhythm after one to three escalating shocks. We report efficacy results for the cohort of patients treated by ALS paramedics who presented with an initially shockable rhythm who had not received a shock from a first responder (MDS: n=83; RLB: n=86). Shock success within the first three ascending energy shocks for RLB (120, 150, 200J) was superior to MDS (200, 300, 360J) for patients initially presenting in a shockable rhythm (52% versus 34%, p=0.01). First shock conversion was 23% and12%, for RLB and MDS, respectively (p=0.07). There were no significant differences in return of spontaneous circulation (47% versus 47%), survival to 24h (31% versus 27%), and survival to discharge (9% versus 7%). Mean 24h survival rates of bystander witnessed events showed differences between waveforms in the early circulatory phase at 4-10 min post event (mean (S.D.) RLB 0.45 (0.07) versus MDS 0.31 (0.06), p=0.0002) and demonstrated decline as time to first shock increased to 20 min. CONCLUSION: Shock success to an organized rhythm comparing step-up protocol for energy settings demonstrated the RLB waveform was superior to MDS in ALS treatment of OHCA. Survival rates for both waveforms are consistent with current theories on the circulatory and metabolic phases of out-of-hospital cardiac arrest.
Authors:
Laurie J Morrison; Paul Dorian; Jennifer Long; Marian Vermeulen; Brian Schwartz; Bruce Sawadsky; Jamie Frank; Bruce Cameron; Robert Burgess; Jennifer Shield; Paul Bagley; Vivien Mausz; James E Brewer; Bruce B Lerman;
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Publication Detail:
Type:  Comparative Study; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Resuscitation     Volume:  66     ISSN:  0300-9572     ISO Abbreviation:  Resuscitation     Publication Date:  2005 Aug 
Date Detail:
Created Date:  2005-08-01     Completed Date:  2005-12-09     Revised Date:  2009-08-25    
Medline Journal Info:
Nlm Unique ID:  0332173     Medline TA:  Resuscitation     Country:  Ireland    
Other Details:
Languages:  eng     Pagination:  149-57     Citation Subset:  IM    
Affiliation:
Prehospital and Transport Medicine Research Program, Sunnybrook and Women's College Health Sciences Centre, Institute for Clinical and Evaluative Sciences, Department of Medicine, University of Toronto, Toronto, Ont., Canada. laurie.morrison@sw.ca
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MeSH Terms
Descriptor/Qualifier:
Adult
Aged
Chi-Square Distribution
Defibrillators
Electric Countershock / methods*
Emergency Medical Services / methods*
Female
Follow-Up Studies
Heart Arrest / diagnosis,  mortality,  therapy*
Humans
Life Support Systems
Male
Middle Aged
Probability
Prospective Studies
Reference Values
Risk Factors
Sensitivity and Specificity
Survival Rate
Treatment Outcome
Ventricular Fibrillation / diagnosis,  mortality*,  therapy*

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


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