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| Name | Class |
|---|---|
| Peel Regional Paramedic Services | UNKNOWN |
| Toronto Paramedic Services | UNKNOWN |
| Halton Region Paramedic Services | OTHER |
| County of Simcoe Paramedic Services |
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Despite significant advances in resuscitation efforts, there are some patients who remain in refractory ventricular fibrillation (VF) during out-of-hospital cardiac arrest. Double sequential external defibrillation (DSED) and vector change defibrillation have been proposed as viable options for patients in refractory VF. This cluster randomized trial will compare (1) continued resuscitation using standard defibrillation; (2) resuscitation involving DSED; or (3) resuscitation involving vector change defibrillation, in patients presenting with refractory VF during out-of-hospital cardiac arrest. The results of this study will provide high level evidence of the impact of both DSED and vector change defibrillation on ROSC and patient survival after OHCA.
Double sequential external defibrillation (DSED) and vector change defibrillation have been proposed as viable options for patients in refractory ventricular fibrillation (VF) during out-of-hospital cardiac arrest. However, currently there is insufficient evidence to support widespread implementation of this therapy. As such, a well-designed randomized controlled trial (RCT) employing a standardized approach to alternative defibrillation strategies early in the treatment of refractory VF is required to determine whether these treatments may impact clinical outcomes. This cluster randomized trial will be conducted in the regions of Peel, Halton, Simcoe, and the cities of London, Ottawa, and Toronto, Ontario, Canada over a three year time period. All adult (≥ 18 years) patients presenting in refractory VF/pulseless ventricular tachycardia (pVT) (defined as patients presenting in VF/pVT and remaining in VF/pVT after three consecutive standard defibrillation attempts each separated by 2 minutes of CPR) during out-of-hospital cardiac arrest of presumed cardiac etiology will be assigned to be treated by one of three strategies: (1) continued resuscitation using standard defibrillation; (2) resuscitation involving DSED (two defibrillators, one using anterior-posterior pad placement and the second using anterior- anterior pad placement delivering two rapid sequential shocks for all subsequent defibrillation attempts); or (3) resuscitation involving vector change (change of defibrillation pads from anterior-anterior to an anterior-posterior pad position) defibrillation. All study arms will continue to receive antiarrhythmic use and epinephrine as per current provincial standards. The cluster units will be defined by emergency medical service (EMS) agency and each cluster will crossover at 6 month intervals throughout the duration of the study.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Standard Arm | No Intervention | All defibrillation attempts will occur using the standard defibrillation method, i.e. defibrillation pads will be placed in the anterior-anterior configuration. The patient may also be administered antiarrythmic agents and epinephrine, as per current provincial standard. | |
| Double Sequential Defibrillation | Active Comparator | The first three shocks will occur with defibrillation pads placed in the anterior-anterior position. For all further shocks, a second set of defibrillation pads (via a second on scene EMS or fire defibrillator) will be applied in the anterior-posterior position, and defibrillation will be carried out by sequential defibrillation shocks provided by the two defibrillators (i.e. with a short delay between the two defibrillators). The patient may also be administered antiarrythmic agents and epinephrine, as per current provincial standard. |
|
| Vector Change Defibrillation | Active Comparator | The first three shocks will occur with defibrillation pads placed in the anterior-anterior position. All further shocks will occur with the pads placed in the anterior-posterior position. The patient may also be administered antiarrythmic agents and epinephrine, as per current provincial standard. |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Double Sequential Defibrillation | Procedure | Defibrillation using pad placement in anterior-posterior position |
|
| Measure | Description | Time Frame |
|---|---|---|
| Survival to Hospital Discharge | Binary outcome of whether the patient was discharged alive from hospital or died prior to discharge. | Through study completion of three years |
| Measure | Description | Time Frame |
|---|---|---|
| Neurologic outcome | Neurologic outcome as defined by the modified Rankin Scale at time of hospital discharge. mRS 0-2 will be considered a good neurologic outcome. | Throughout study completion of three years |
| Return of Spontaneous Circulation |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Sheldon Cheskes, MD | Sunnybrook Centre for Prehospital Medicine | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Peel Regional Paramedic Service | Brampton | Ontario | Canada | |||
| Middlesex-London Paramedic Service |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 33243277 | Background | Drennan IR, Dorian P, McLeod S, Pinto R, Scales DC, Turner L, Feldman M, Verbeek PR, Morrison LJ, Cheskes S. DOuble SEquential External Defibrillation for Refractory Ventricular Fibrillation (DOSE VF): study protocol for a randomized controlled trial. Trials. 2020 Nov 26;21(1):977. doi: 10.1186/s13063-020-04904-z. | |
| 32084567 | Background |
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| Type | Includes Protocol | Includes SAP | Includes ICF | Document Label | Document Date | Document Uploaded Date | Document File Name |
|---|---|---|---|---|---|---|---|
| Prot_SAP | Yes | Yes | No | Study Protocol and Statistical Analysis Plan | Jun 11, 2021 | Feb 21, 2022 | Prot_SAP_000.pdf |
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| ID | Term |
|---|---|
| D058687 | Out-of-Hospital Cardiac Arrest |
| D014693 | Ventricular Fibrillation |
| D001145 | Arrhythmias, Cardiac |
| D006331 | Heart Diseases |
| D006323 | Heart Arrest |
| ID | Term |
|---|---|
| D002318 | Cardiovascular Diseases |
| D010335 | Pathologic Processes |
| D013568 | Pathological Conditions, Signs and Symptoms |
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| UNKNOWN |
| London Health Sciences Centre | OTHER |
| Middlesex-London EMS | UNKNOWN |
| Ottawa Paramedic Service | UNKNOWN |
This is a cluster randomized trial, with cluster units defined by EMS agency. Each cluster will crossover at six month intervals for each EMS agency during the study.
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| Vector Change Defibrillation | Procedure | Defibrillation using two defibrillators, one with pad placement in anterior-posterior position and the other with pad placement in anterior-anterior position delivering two rapid sequential shocks. |
|
Binary outcome of whether or not a patient had a return of spontaneous circulation
| 1 Day |
| VF termination after first interventional shock | Cessation of the VF waveform on defibrillator monitor at first rhythm analysis post interventional or standard shock. The interpretation will occur after three standard shocks have failed to terminate VF | 1 Day |
| VF Termination after all interventional shocks | Cessation of the VF waveform on defibrillator monitor at any rhythm analysis post interventional or standard shock. The interpretation will occur after three standard shocks have failed to terminate VF | 1 Day |
| Number of defibrillation attempts to achieve Return of spontaneous circulation | Total number of shocks required to achieve the first return of spontaneous circulation during resuscitation, inclusive of the first three standard shocks | 1 Day |
| London |
| Ontario |
| Canada |
| Halton Region Paramedic Services | Oakville | Ontario | Canada |
| Ottawa Paramedic Service | Ottawa | Ontario | Canada |
| County of Simcoe Paramedic Services | Simcoe | Ontario | Canada |
| Toronto Paramedic Services | Toronto | Ontario | Canada |
| Cheskes S, Dorian P, Feldman M, McLeod S, Scales DC, Pinto R, Turner L, Morrison LJ, Drennan IR, Verbeek PR. Double sequential external defibrillation for refractory ventricular fibrillation: The DOSE VF pilot randomized controlled trial. Resuscitation. 2020 May;150:178-184. doi: 10.1016/j.resuscitation.2020.02.010. Epub 2020 Feb 19. |
| 40483934 | Derived | Cheskes S, McLeod SL. Double sequential external defibrillation for refractory ventricular fibrillation: the science, the controversies and the future. J Electrocardiol. 2025 Jul-Aug;91:154046. doi: 10.1016/j.jelectrocard.2025.154046. Epub 2025 Jun 4. |
| 36342151 | Derived | Cheskes S, Verbeek PR, Drennan IR, McLeod SL, Turner L, Pinto R, Feldman M, Davis M, Vaillancourt C, Morrison LJ, Dorian P, Scales DC. Defibrillation Strategies for Refractory Ventricular Fibrillation. N Engl J Med. 2022 Nov 24;387(21):1947-1956. doi: 10.1056/NEJMoa2207304. Epub 2022 Nov 6. |