Evidence map›Paper›PMID 41680915›Full record

Trial reportCritical care (London, England)2026

On-scene selective brain cooling in ventricular fibrillation cardiac arrest: pilot results from the PRINCESS2 randomised trial.

Emelie Dillenbeck, Thomas Berthelsen, Ervigio Corral Torres, Esteban López-de-Sa, Sandra O Rosillo Rodríguez, Miguel Sanchez-García, Juan Carlos Martín Benítez, Hans-Jörg Busch, Peter Radsel, Giuseppe Ristagno and 15 more

Registry-linked trialAbstract readRandomized Controlled TrialMulticenter Study
In one paragraph

Trial report in Critical care (London, England), 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT06025123 (Prehospital Resuscitation Intranasal Cooling Effectiveness Survival Study 2), which is not on this map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

NCT06025123 narecruitingnot on this map

Prehospital Resuscitation Intranasal Cooling Effectiveness Survival Study 2 (PRINCESS2)

TypeinterventionalSponsorKarolinska InstitutetRan2024 to 2028Enrolled1,022ConditionsOut-Of-Hospital Cardiac Arrest, Hypothermia, Ventricular FibrillationArmsEarly transnasal evaporative cooling with the RhinoChill device
3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

25 authors.

Emelie DillenbeckDepartment of Clinical Science and Education, Center for Resuscitation Science, Karolinska Institutet, Södersjukhuset, Stockholm, Sweden. emelie.dillenbeck@ki.se.
Thomas BerthelsenDepartment of Physiology and Pharmacology , Karolinska Institutet , Stockholm, Sweden.
Ervigio Corral TorresSAMUR Protección Civil , Madrid, Spain.
Esteban López-de-SaCardiovascular Research Division , CARDIO-ELA , Madrid, Spain.
Sandra O Rosillo RodríguezDepartment of Cardiology, Acute Cardiac Care Unit, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain.
Miguel Sanchez-GarcíaCritical Care Department , Hospital Clínico San Carlos , Madrid, Spain.
Juan Carlos Martín BenítezCritical Care Department , Hospital Clínico San Carlos , Madrid, Spain.
Hans-Jörg BuschDepartment of Emergency Medicine, Faculty of Medicine, University Hospital of Freiburg,University of Freiburg, Freiburg, Germany.
Peter RadselCenter for Intensive Internal Medicine , University Medical Center , Ljubljana, Slovenia.
Giuseppe RistagnoDepartment of Anesthesiology, Intensive Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy.
Graham NicholUniversity of Washington-Harborview Center for Prehospital Emergency Care , University of Washington , WA, Seattle, USA.
Michael HolzerDepartment of Emergency Medicine, Medical University of Vienna, Vienna, Austria.
Anthony MoreauDepartment of Intensive Care, Hôpital Universitaire de Bruxelles (HUB), Université libre de Bruxelles (ULB), Brussels, Belgium.
Sune ForsbergDepartment of Clinical Science and Education, Center for Resuscitation Science, Karolinska Institutet, Södersjukhuset, Stockholm, Sweden.
Denise BäckströmDepartment of Biomedical and Clinical Sciences , Linköping University , Linköping, Sweden.
Akil AwadDepartment of Clinical Science and Education, Center for Resuscitation Science, Karolinska Institutet, Södersjukhuset, Stockholm, Sweden.
Fabio Silvio TacconeDepartment of Intensive Care, Hôpital Universitaire de Bruxelles (HUB), Université libre de Bruxelles (ULB), Brussels, Belgium.
Anna FalkDepartment of Physiology and Pharmacology , Karolinska Institutet , Stockholm, Sweden.
Jacob HollenbergDepartment of Clinical Science and Education, Center for Resuscitation Science, Karolinska Institutet, Södersjukhuset, Stockholm, Sweden.
Martin JonssonDepartment of Clinical Science and Education, Center for Resuscitation Science, Karolinska Institutet, Södersjukhuset, Stockholm, Sweden.
Andreas LiliequistDepartment of Physiology and Pharmacology , Karolinska Institutet , Stockholm, Sweden.
Juliane JurgaDepartment of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.
Mantas OkasDepartment of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Stockholm, Sweden.
Leif SvenssonDepartment of Clinical Science and Education, Center for Resuscitation Science, Karolinska Institutet, Södersjukhuset, Stockholm, Sweden.
Per NordbergDepartment of Clinical Science and Education, Center for Resuscitation Science, Karolinska Institutet, Södersjukhuset, Stockholm, Sweden.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundAlthough ischemia-reperfusion brain injury represents a major clinical problem after cardiac arrest, no neuroprotective treatment currently exists. The PRINCESS2 trial is designed to confirm previous findings, indicating that on-scene selective brain cooling using a portable trans-nasal cooling method improves complete neurological recovery after out-of-hospital cardiac arrest (OHCA) with initial shockable rhythms (e.g. ventricular fibrillation). This prespecified pilot phase aimed to assess protocol adherence and safety aspects for this early cooling strategy.

methodsThe prespecified pilot phase includes the first 100 patients in the main PRINCESS2 trial, an ongoing European multicentre trial enrolling 1,022 OHCA patients with initial shockable rhythm. Patients are randomised to intervention; trans-nasal cooling initiated at the scene of arrest followed by systemic hypothermia (33 ± 0.5 °C for 24 h) in the intensive care unit, or control; normothermia with fever control. Neuroprognostication and criteria for withdrawal of life-sustaining treatment are protocolised. Pilot outcomes were adherence to treatment allocation and protocol in the prehospital and in-hospital stages, and safety aspects, including 72-hour survival, prehospital re-arrest, device-related adverse events, and adverse events within 7 days such as bleeding, sepsis, arrhythmias with hemodynamic compromise, or need for circulatory support.

resultsIn total, 100 patients were randomised (median age 64 years, 91% male) to intervention (n = 50) or control (n = 50). All intervention patients received allocated treatment. Four had minor trans-nasal cooling interruptions, and two had systemic cooling interruptions. Among controls, 48/50 received allocated treatment, while two crossed over to cooling. One control was lost to follow-up. Overall, adherence to allocation and treatment protocol was 92%. Survival to 72 h was similar (intervention: 32/50 [64%], control: 31/49 [63%]) as well as prehospital re-arrest rates (11/49 [22%] vs. 9/40 [23%]). No device-related serious adverse events occurred. Adverse event rates within 7 days were similar.

conclusionIn this pilot phase of the PRINCESS2 trial, on-scene trans-nasal cooling in OHCA patients with shockable rhythms was performed with high protocol adherence without safety concerns. The main trial will continue as planned.

trial registrationClinicalTrials.gov: NCT06025123, registered Feb 1, 2023.

Indexed as

Hypothermia, InducedOut-of-Hospital Cardiac ArrestVentricular FibrillationAgedBrainFemaleHumansMaleMiddle AgedPilot ProjectsNeurological recoveryOut-of-hospital cardiac arrestPrehospital coolingTherapeutic hypothermiaVentricular fibrillation

Identifiers

PMID41680915
PMCPMC12930594

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Registered trials

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.