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The pilot study

The DoubleD pilot study is an academically driven, prospective, randomized, pilot study based in Sweden. The study is coordinated by the Center for Resuscitation Science at Karolinska Institutet, Stockholm.

The aim of this pilot study was to evaluate the feasibility of conducting a randomized controlled trial to compare double sequential defibrillation (DSD) as early as possible with standard defibrillation in patients with out-of-hospital cardiac arrest who remain in ventricular fibrillation (VF)/pulseless ventricular tachycardia (pVT) after the first defibrillation.

The pilot study used 3:1 randomization (3 DSD: 1 standard) and was planned to continue until 40 patients have been enrolled. Patients were randomized by specially trained ambulance personnel at the scene of the cardiac arrest to receive either DSD (intervention) or standard defibrillation (control). The pilot study was conducted within the ambulance services in Alingsås, Kungälv, and Sahlgrenska University Hospital. If successful, the goal is to proceed with a larger main study evaluating survival outcomes.

Enrollment is now complete and the pilot study has been closed to further recruitment.

Inclusion criteria

  • Out-of-hospital cardiac arrest where at least one defibrillation has been performed (it does not matter who performed the initial defibrillation[s]).

  • There must be two defibrillators on scene that are approved for double defibrillation. As of October 2024, only Corpuls3 + Corpuls3 are permitted for use.

Exclusion criteria

  • Age under 18 years.
  • Patients with known or visibly apparent pregnancy.
  • Previously established ”Do Not Resuscitate” (DNR) order.

Outcomes include feasibility and safety as follows:

Feasibility:

  • The number of defibrillations by the ambulance before randomization (target >80% before the third defibrillation).
  • Among patients randomized to DSD, the proportion who received DSD (target >80%).
  • Among patients randomized to standard, the proportion who received DSD (target <10%).
  • The proportion of patients who met the inclusion criteria and were included and randomized (target >80%).

Safety:

  • Serious adverse effects (such as defibrillator failure).
  • Interruptions in chest compressions during CPR (defined as the proportion of time during CPR when chest compressions are being performed; target >80% in both groups).

Patient outcomes:

  • The proportion in each group who regained sustained circulation.
  • Number of defibrillations before return of sustained circulation in each group.
  • The proportion of patients who are alive upon arrival at the hospital.
  • The proportion of patients who are alive at hospital discharge.
  • 30-day survival.
  • Neurological function 30 days after cardiac arrest.
  • Neurological function and health-related quality of life at 90 and 180 days.

For detailed information, secondary and tertiary outcomes, as well as methodology, see CIP or CIP-summary. 

If management with early DSD is demonstrated by this pilot study to be feasible and safe, then a larger randomized controlled trial will be pursued. This will naturally include a much larger number of patients and emergency medical services.