Trial flowchart

Strategies for Defibrillation During Out-of-Hospital Cardiac Arrest

The STRAT-DEFI trial is a randomized clinical trial evaluating defibrillation strategies during adult out-of-hospital cardiac arrest.

The aim of this trial is to determine whether there is a difference in survival when using anterior-posterior defibrillation or double sequential defibrillation as compared to standard anterior-lateral defibrillation in out-of-hospital cardiac arrest with a refractory shockable rhythm.

The primary outcome will be survival at 30 days. Secondary outcomes will be 90-day survival and neurological outcome at 30 and 90 days.

This trial will be an investigator-initiated, individually randomized, patient- and outcome assessor-blinded, parallel 3-group trial. Patients will be randomized in a 1:1:1 ratio by opening a randomization envelope on-site.

Trial information

Out-of-hospital cardiac arrest affects around 4 million people worldwide each year, including about 5,000 in Denmark. Patients with shockable rhythms have improved outcomes compared to patients with non-shockable, but 75% do not respond to initial defibrillation, of these only 1 in 5 are alive after 30 days.

Defibrillation methods for these patients have not changed significantly in 50 years, new approaches are needed to improve patient outcomes.

The current guidelines recommended for pads to be placed in an anterior-lateral position. Alternative defibrillation strategies can be considered for patients with refractory shockable rhythms. The first approach changes the defibrillation pads to an anterior-posterior position, which is theorized to shock the ventricles specifically. The second option, double sequential defibrillation, is a combination of the two pad placements, resulting in a setup with 4 pads and two defibrillators. Two shocks are then delivered in quick succession.

A recent trial reported improved survival rates using these alternative defibrillation strategies for patients with refractory shockable rhythms. The trial has been met with skepticism because of a series of limitations.

The trial will be conducted nationwide in Denmark and will have additional participation from international sites. Adults in non-traumatic out-of-hospital cardiac arrest will be eligible for inclusion after one defibrillation attempt by emergency medical services and when two defibrillators are present on-site.

Due to the nature of the intervention, the clinicians performing the intervention cannot be blinded. Patients along with any legally designated representatives will be blinded. Investigators involved in data entry will not be blinded meaning that outcomes such as survival are entered without blinding. Outcome assessors performing the follow-up interviews will be blinded as this involves outcomes with some degree of subjectivity.

A patient, or alternatively the consenting legally designated representatives, will not be informed of the allocation until the end of follow-up and only per request on the consent form.

This trial includes unconscious patients that are unable to provide informed consent. Given the urgency of the intervention, it is not possible to obtain consent from a surrogate (e.g. family member). In accordance with European regulations and Danish law, patients are included without prior consent. As soon as possible, consent for future data collection will be obtained from the patient or a surrogate.

For a detailed description of the trial see the protocol on the trial documents page

Intervention groups

The trial will randomize patients to one of three intervention groups. The allocation ratio between the groups will be 1:1:1

Anterior-lateral

At time of randomization, pads will be placed in the anterior-lateral position as this is the current standard of care. Patients randomized to anterior-lateral pad placement will keep their initial pad placement, with the anterior pad placed to the right of the sternum, below the calvicle. The lateral pad is placed in the mid-axillary line in level with the bottom of the pectoralis muscle for men, and below the breast for women.

Anterior-posterior

The intervention will alter the defibrillation pad placement from anterior-lateral to anterior-posterior. After randomization and as soon as possible, new defibrillation pads will be placed on the patient in the anterior-posterior position. The anterior pad will be placed to the left of the sternum. The posterior pad must be placed to the left of the thoracic spine and below the spine of the scapula.

Double sequential defibrillation

The intervention will alter the defibrillation method from single-shock anterior-lateral to double sequential defibrillation. Two seperate defibrillators with anterior-lateral and anterior-posterior pad placement, will be triggered in quick succession.

The two defibrillators must be operated by the same clinician. The shocks are administered separately but sequentially.

Sites

Prehospital Emergency Medical Services, Central Denmark Region

Olof Palmes Allé 34, 1.

8200 Aarhus N

Denmark

Site investigator: Bertram Lahn Kirkegaard

Emergency Medical Services, the North Denmark Region

Hjulmagervej 20

9000 Aalborg

Denmark

Site investigator: Thomas Lass Klitgaard

Emergency Medical Services, the Region of Southern Denmark

Damhaven 12

7100 Vejle

Denmark

Site investigator: Søren Mikkelsen

Copenhagen Emergency Medical Services, the Capital Region of Denmark

Telegrafvej 5

2750 Ballerup

Denmark

Site investigator: Fredrik Folke

The Prehospital Center, Region Zealand

Ringstedgade 61, 13.

4700 Næstved

Denmark

Site investigator: Helle Collatz Christensen

Danish Air Ambulance, Danish Regions

Brendstrupgårdsvej 7, 2. th
8200 Aarhus N

Denmark

Site investigator: Jacob Steinmetz

Finland sites to be added

Belgium sites to be added

Funding

the Independent Research Fund Denmark
The Novo Nordisk Foundation

The funding agency has no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; or the decision to submit the manuscript for publication.