{
  "abstract": "Background Double sequential defibrillation (DSD) is a promising treatment for patients with out-of-hospital cardiac arrest (OHCA) with refractory ventricular fibrillation. The reproducibility and generalisability of previous studies are unknown. Additionally, whether DSD could improve survival if applied earlier has never been studied. The DoubleD trial aims to establish whether early DSD (as soon as possible after the first shock) is superior to standard defibrillation. This pilot study evaluated the safety and feasibility of this strategy in preparation for the main trial.Methods This Swedish, prehospital, open-label, randomised controlled external pilot trial enrolled patients with OHCA who were still in cardiac arrest after at least one defibrillation in the standard (anterior-lateral) position. Enrolment required two ambulances with manual defibrillators to be present. The inclusion goal was 40 patients, randomised 3:1 to early DSD (with a second defibrillator in the anterior-posterior position) or continued standard defibrillation. Data were collected from study questionnaires, medical charts and defibrillators. The main feasibility and safety outcomes were randomisation prior to three shocks, adherence to protocol and defibrillator malfunction.Results Between June 2024 and April 2025, 40 patients were randomised: 29 to early DSD and 11 to standard defibrillation. Overall, 32/40 (80%) were randomised before the third defibrillation. In the DSD group, 20/21 (95%) of patients who still had a shockable rhythm after randomisation received DSD. One case of treatment crossover occurred in both DSD and control groups. No defibrillator malfunctions or adverse events were observed. 30-day survival was 12/29 (41%) and 1/11 (9%) for the DSD and control group respectively.Conclusion This is the first time that early DSD has been investigated in clinical practice. The strategy is feasible and appears to be safe. The findings have informed the design of the DoubleD main trial, powered to assess 30-day survival ( NCT07174986).Trial registration number NCT06447805.",
  "authors": [
    {
      "affiliations": [
        "Department of Clinical Science and Education Södersjukhuset, Center for Resuscitation Sciences, Karolinska Institute, Stockholm, Sweden"
      ],
      "name": "Gabriel Riva"
    },
    {
      "affiliations": [
        "Department of Clinical Science and Education Södersjukhuset, Center for Resuscitation Sciences, Karolinska Institute, Stockholm, Sweden"
      ],
      "name": "Emma Blick Nordkvist"
    },
    {
      "affiliations": [
        "Department of Molecular and Clinical Medicine, University of Gothenburg Sahlgrenska Academy, Gothenburg, Sweden",
        "Department of Prehospital Emergency Care, Sahlgrenska University Hospital, Gothenburg, Sweden"
      ],
      "name": "Carl Magnusson"
    },
    {
      "affiliations": [
        "Department of Clinical Science and Education Södersjukhuset, Center for Resuscitation Sciences, Karolinska Institute, Stockholm, Sweden"
      ],
      "name": "Andreas Claesson"
    },
    {
      "affiliations": [
        "Department of Clinical Science and Education Södersjukhuset, Center for Resuscitation Sciences, Karolinska Institute, Stockholm, Sweden"
      ],
      "name": "Martin Jonsson"
    },
    {
      "affiliations": [
        "Department of Internal Medicine, Kalmar County Hospital, Kalmar County Council, Kalmar, Sweden"
      ],
      "name": "Johan Israelsson"
    },
    {
      "affiliations": [
        "Department of Clinical Science and Education Södersjukhuset, Center for Resuscitation Sciences, Karolinska Institute, Stockholm, Sweden"
      ],
      "name": "Cecilia Nordius"
    },
    {
      "affiliations": [
        "Department of Molecular and Clinical Medicine, University of Gothenburg Sahlgrenska Academy, Gothenburg, Sweden"
      ],
      "name": "Kajsa Barret"
    },
    {
      "affiliations": [
        "Center for Resuscitation Science, Karolinska Institute, Stockholm, Sweden",
        "Department of Anaesthesia, Operation, and Intensive Care, Södertälje Sjukhus, Södertälje, Sweden"
      ],
      "name": "David Brooke Sidebottom"
    },
    {
      "affiliations": [
        "Department of Anesthesiology and Intensive Care Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden"
      ],
      "name": "Patrik Martner"
    },
    {
      "affiliations": [
        "Department of Anesthesiology and Intensive Care Medicine, Sahlgrenska Academy, Gothenburg, Sweden"
      ],
      "name": "Oscar Cavefors"
    },
    {
      "affiliations": [
        "Department of Anesthesiology and Intensive Care Medicine, University of Gothenburg, Gothenburg, Sweden"
      ],
      "name": "Anders Tenning"
    },
    {
      "affiliations": [
        "Institute of Health and Care Sciences, Sahlgrenska Academy, University of Gothenburg, Sahlgrenska Academy, Gothenburg, Sweden",
        "Department of Ambulance and Prehospital Care, Region Halland, Halmstad, Sweden"
      ],
      "name": "Kristoffer Wibring"
    },
    {
      "affiliations": [
        "Department of Cardiology, Vrinnevisjukhuset i Norrkoping, Norrköping, Sweden"
      ],
      "name": "Annette Waldemar"
    },
    {
      "affiliations": [
        "Department of Cardiology, Sahlgrenska universitetssjukhuset, Gothenburg, Sweden"
      ],
      "name": "Gunilla Edholm"
    },
    {
      "affiliations": [
        "Department of Clinical Science and Education Södersjukhuset, Center for Resuscitation Sciences, Karolinska Institute, Stockholm, Sweden"
      ],
      "name": "Akil Awad"
    }
  ],
  "title": "Feasibility of early double sequential defibrillation in out-of-hospital cardiac arrest: the double-D randomised pilot trial",
  "uid": "8c1883ad-1488-53e4-b60c-74de196afdd6"
}