Center for Resuscitation Science – Jacob Hollenberg's research group

Cardiac arrest is a major health issue. Only about 10% survive out-of-hospital cardiac arrest and in-hospital the number is approximately 30%. With a coherent chain of care and world leading research, more can be saved.

Part of the:

Our Research

The overall purpose of this center is to generate and disseminate knowledge about cardiac arrest through education and research at various levels, as well as to create scientific foundations for optimizing care and increasing patient survival. 

The Center for Resuscitation Science is aiming to improve survival rates in cardiac arrest and to enhance the state of knowledge by conducting prospective clinical studies, promoting development, and influencing public opinion. The Research Board at Karolinska Institutet found it crucial to establish this knowledge center. The center’s primary focus is to conduct clinical and patient-centered research that can lead to improved survival in cases of out-of-hospital cardiac arrest. This is achieved by developing new treatment methods and providing on-site assistance to patients—whether in their homes, workplaces, public places, ambulances, or hospitals. 

The research and development program at the Center for Resuscitation Science currently consists of about ten main research projects. These projects cover everything from new technological innovations and treatments at home and in the community, to interventions at the emergency dispatch center, in ambulances, and hospitals, encompassing all elements of the "chain of survival" concept. The program, conducted within the framework of the center's work, aims to answer clear clinical questions and is therefore highly clinically anchored. The generalizability of the expected results—regardless of the outcomes—can be considered high, as these involve large-scale clinical intervention studies addressing areas where randomized trials are lacking today.  

The Center for Resuscitation Science at the Department of Clinical Research and Education, Södersjukhuset, conducts research in cardiac arrest and cardiovascular diseases. The group is composed of a multidisciplinary team of physicians, nurses, statisticians, and economists. There is also a strong ambition to further balance the group from a gender perspective. Additionally, the center aims to establish eight individual research tracks, each led by postdoctoral researchers from the group.

The vision of the Center for Resuscitation Science is to conduct world-leading clinical intervention research aiming to increase survival in cardiac arrest.

Centrum för Hjärtstoppsforskning
The Center for Resuscitation Science. Photo: Hjärt-lungfonden

Collaboration

The Center for Resuscitation Science is a well-established national and international research network, including Professor Sten Rubertsson (cardiac arrest) and Professor Stefan James (cardiology) from Uppsala, as well as Professor Johan Herlitz from Gothenburg. Furthermore, there is strong research collaboration with Professor Kramer-Johansen and Theresa Olafsvengen in Norway, Professor Freddy Lippert and Fredrik Folke in Denmark, Professor Fabio Taccone in Belgium, and Professor Koster in the Netherlands. All these groups are involved in one or more of the planned projects described above. 

The Center for Resuscitation Science also has a well-established network with other organizations and authorities, such as the Swedish Association of Local Authorities and Regions (SKR), the Swedish National Agency for Education, the Association for Management Responsibility in Swedish Ambulance Services (FLISA), the Swedish Civil Contingencies Agency (MSB), the Fire and Rescue Services, and the Police Authority. Additionally, it collaborates within acute cardiology through SWEDEHEART, stroke care, emergency departments, as well as within administration, businesses, universities, and governmental agencies. 

The Swedish CPR Registry and the Swedish Resuscitation Council are involved in the implementation of research findings and the development of new guidelines and training programs for CPR. Other collaborating organizations include the Swedish Life Saving Society, the Swedish Sea Rescue Society, the Coast Guard, and the Armed Forces. 

The aim of these networks is to conduct both prehospital and in-hospital studies, gather input from various operations, and implement research findings into society.

International collaborations

COSTA

This consortium brings together leading researchers in the field of cardiac arrest treatment. The aim is to compile a cohort of research data to shed light on and answer various clinical questions. Additionally, to exchange experiences and research ideas, as well as contribute to clinical implementation and quality review within and between the participating regions. 

The participating regions include Oslo, Copenhagen, Amsterdam, and Stockholm. The consortium holds multiple in-person meetings annually, along with monthly teleconferences. Several studies have been published as part of this collaboration. 

Academic institutions involved in the consortium include: 

  • AMC bij de Universiteit van Amsterdam
  • Region Hovedstaden, EMS Copenhagen
  • Oslo University Hospital, Division of Emergencies and Critical Care 

The European Sudden Cardiac Arrest network towards Prevention, Education, New Effective Treatment (ESCAPE-NET)

ESCAPE-NET is a major European research consortium aimed at increasing survival rates after cardiac arrest. It has established an infrastructure and compiled large European cardiac arrest cohorts with essential information, including DNA samples collected during resuscitation. These international cohorts, in which the Center for Resuscitation Science represents Sweden, are already world leading in terms of size and data quality. 

ESCAPE-NET's ambition is to further enhance these cohorts synergistically by adding new data on potential risk factors that have so far been underappreciated in cardiac arrest research—particularly socioeconomic and psychosocial stress factors. These new data will be obtained by ESCAPE-NET partners specializing in linking study cohorts to regional and national registries containing this information. 

A comprehensive integration strategy for these exceptionally large and complete datasets represents an innovative approach in cardiac arrest research. Mattias Ringh and Martin Jonsson are members of the ESCAPE-NET steering group.

PRINCESS – Early Hypothermia Treatment

The PRINCESS study network, led by principal investigator Per Nordberg, included 11 study sites across seven countries (Belgium, Germany, the Czech Republic, France, Spain, England, and Sweden). Several collaborations with these national principal investigators continue through substudies, which are part of multiple dissertations, as well as through a planned follow-up study on early hypothermia treatment in cardiac arrest. 

A particularly well-developed research collaboration has existed for over a decade with Erasme University Hospital in Brussels, involving the research group led by Professor Fabio Silvio Taccone and Professor Jean-Louis Vincent. This partnership has resulted in 7–8 joint publications. 

In 2019, a collaboration was initiated with Professor Benjamin Abella from the University of Pennsylvania and Professor Lance Becker from University Hospital Northwell Health in Manhasset, NY—both world-leading researchers in hypothermia treatment for cardiac arrest. Collaborative work on several studies has begun, with one study already published.

Organisation

The Center for Resuscitation Science is led by a steering group, a scientific executive committee, and an administrative group.

Steering group

The Committee for Research at Karolinska Institutet decided on November 30, 2020, according to Chair Decision 2020:68, on the Steering Group for the Center for Resuscitation Science

  • Jacob Hollenberg (JH), Institution for Clinical Research and Education, Södersjukhuset. Also Department of Cardiology, Södersjukhuset. Chair.
  • Andreas Claesson (AC), Institution for Clinical Research and Education, Södersjukhuset. Also Department of Cardiology, Södersjukhuset.
  • Anette Nord, Institution for Clinical Research and Education, Södersjukhuset
  • Sune Forsberg, Institution for Clinical Research and Education, Södersjukhuset. Also Also Medical Director Norrtälje hospital.
  • Erik Melén, Head of Department, Karolinska Institutet, Södersjukhuset
  • Karouk Said, Medical Director, Södersjukhuset.
  • Raffaele Scorza, Head of Department of Cardiology, Södersjukhuset.
  • Jon Pernow, deputy head of department, KI-Medicine, Solna
  • Yifang Bang, professor KTH.

The Steering Group is responsible for the strategic direction of the operations. The group is required to meet at least once a year.

Scientific Executive Committee 

The Scientific Executive Committee is responsible for the scientific review and for setting concrete goals and monitoring the operations over time. The committee works to ensure that the activities at the Cardiac Arrest Center maintain high quality in all aspects. The group is required to meet 2-3 times per semester.

  • Jacob Hollenberg, Professor, Senior Consultant in Cardiology. Chair.
  • Andreas Claesson, Associate Professor, Registered Ambulance Nurse.
  • Sune Forsberg, Associate Professor, Senior Consultant in Anesthesia and Intensive Care.
  • Therese Djärv, Professor, Specialist in Emergency Medicine.
  • Leif Svensson, Senior Professor, Senior Consultant in Cardiology.
  • Mårten Rosenqvist, Senior Professor, Senior Consultant in Cardiology.
  • Mattias Ringh, Post-doc, Senior Consultant in Cardiology.
  • Per Nordberg, Associate Professor, Senior Consultant in Cardiology.
  • Anette Nord, Post-doc, Registered Nurse.
  • Martin Jonsson (MJ), Post-doc, Health Scientist.

Administrative Group

  • Anette Boban (AB), Medical Secretary
  • Andreas Claesson (AC), Associate Professor, Registered Ambulance Nurse. Chair.
  • Jacob Hollenberg (JH), Associate Professor, Senior Consultant in Cardiology.
  • Mattias Ringh (MR), Post-doc, Senior Consultant in Cardiology.
  • Anna-Sofia Hallberg Börjesson (ASB), Spec Nurse in Intensive Care and Cardiac Care, Coordinator

About us

The Center for Resuscitation Science was established in the early 2000s and consists of approximately 25 researchers, project managers, statisticians, and research assistants currently running more than 10 major projects related to cardiac arrest. The center has well-suited facilities at the Department of Cardiology, Södersjukhuset, with access to Karolinska Institutes research services, including statistical support, IT services, and doctoral student assistance. In addition, there is access to the hospital’s legal services, IT and communications departments, as well as photography and reprographic services. The group also benefits from administrative support and registrars. 

Over the past few years, the Center for Resuscitation Science has conducted a large number of randomized and non-randomized prospective clinical studies. The research is primarily based at the Medical Intensive Care Unit (MIVA) within the cardiology department, where several researchers have their clinical affiliation. However, research activities are spread across the entire Region Stockholm, with members and active research at all major emergency hospitals in the region. The group is multidisciplinary, comprising physicians, nurses, statisticians, and economists, with a strong ambition to achieve further gender balance. 

The group is currently led by Jacob Hollenberg and Andreas Claesson. A key objective is for each participant to take significant responsibility for the research process early in their academic career. With support from supervisors, doctoral students are responsible for applications, budgets, protocols, and project planning. Several times a year, research projects are discussed by the entire group, fostering involvement in each other’s work and offering everyone the opportunity to contribute. 

Independent writing is a vital part of the process, and there is extensive collaboration among group members. Health and a balance between research commitments, clinical work, and family life is emphasized to ensure that researchers remain motivated to combine clinical practice with research and supervision even after completing their doctoral degrees. Each postdoctoral researcher is responsible for their research track, including media relations, collaboration exchanges, and publications. 

The research leader holds regular career discussions with doctoral students and postdocs to ensure that they develop at their own pace, taking into account social and workload factors. The overarching goal is to create a research environment and career opportunities comparable to those in clinical practice. 

Publications

Selected publications

Funding

Jacob Hollenberg
Jacob Hollenberg is awarded Prince Daniel's research grant. 2019 Photo: Heart-Lung Foundation
  • Heart-Lung Foundation
  • Region Stockholm
  • Laerdal Foundation
  • Eurostars / Vinnova

Staff and contact

Group leader

All members of the group

Contact Information

For inquiries to the department, Research Administrator: 
Malin Holm-Blomqvist 

For questions about doctoral education: forskarutbildning@kisos.ki.se 

For applications for new doctoral students: antagning.forskarutbildning@kisos.ki.se 

For travel inquiries and room bookings: anette.boban@regionstockholm.se   

Research Projects

SMS
Everdrone defibrillator drone
Livräddning drunkning
Image gallery

Summary of some of the most central research and development projects

Principal Investigator: Jacob Hollenberg     
Doctoral Student: Erik Boberg  
Research Question: Is a simplified CPR method with chest compressions only equivalent to standard CPR, which includes both compressions and rescue breaths? 

Traditionally, CPR has involved both rescue breaths and chest compressions. However, few randomized studies have been published on the subject. Our NEJM-published study suggests that individuals without prior CPR-training are more likely to provide effective help during a cardiac arrest when guided by emergency dispatchers to perform simplified CPR with chest compressions only. 

Whether simplified CPR results in survival rates comparable to or even better than, standard CPR (with both compressions and rescue breaths) when the bystander has prior CPR training has never been studied. There is strong evidence that a simplified method not only increases the likelihood that bystanders will attempt CPR but also has the potential to improve survival outcomes. 

The TANGO2 Study investigates whether telephone-assisted CPR should be performed with or without rescue breaths for adults experiencing out-of-hospital cardiac arrest while awaiting ambulance arrival. The study, led by the Center for Resuscitation Science, began in January 2017. To date, approximately 2,000 patients have been randomized. Data from the initial phase has been published, demonstrating that the randomization process, implementation, and technical aspects are working well. A doctoral thesis in this area has already been defended (Riva, 2019). For more information, visit TANGO2. 

Principal Investigators: Mattias Ringh and Jacob Hollenberg 
Research Question: Can the dispatch of volunteer lay rescuers via mobile phones increase the proportion of patients who receive early defibrillation and improve survival rates? 

Survival following out-of-hospital cardiac arrest (OHCA) is approximately 10%. However, if a defibrillator is used within the first few minutes after collapse, survival can reach 50–70%. Swedish data show that public access defibrillators (PADs) are rarely used in emergencies. It is estimated that there are about 50,000 public defibrillators in Sweden, but their utilization rate is only around 5%. The main reason for this is a lack of awareness of their existence. Our study is the first in the world to conduct a randomized evaluation of a completely new concept—recruiting both volunteers lay rescuers and defibrillators located near the site of cardiac arrest. 

In a doctoral project and a study published in the New England Journal of Medicine (June 2015), we presented randomized data from the SMS Responder Project, showing that the proportion of patients receiving CPR increased by 30% with the help of our simplified SMS alert system. This research has led to two doctoral theses (Ringh 2016, Berglund 2020). The method is now implemented in most regions in Sweden and across all of Denmark. This is a collaborative project with the University of Copenhagen and Sahlgrenska Academy. 

Principal Investigator: Jacob Hollenberg  
Research Question: Can simultaneous dispatch of ambulance, police, and fire services reduce the time to defibrillation and improve survival rates? 

The number of ambulances per capita is decreasing, and response times are unfortunately increasing in Sweden. Our Stockholm model has gained significant attention worldwide, though no major national studies have been published. Our studies, published in Resuscitation and JAHA, have demonstrated survival benefits from dispatching fire services. The method is now implemented in clinical practice across nearly all of Sweden. This has led to three doctoral theses in the field (Hollenberg 2008, Nordberg 2014, Hasselqvist-Ax 2018). The project is complete, and implementation is ongoing throughout the Nordic region. 

Principal Investigator: Andreas Claesson 
Doctoral Student: Sofia Schierbeck  
Research Question: Can the deployment of a drone with a defibrillator shorten the time to defibrillation and improve survival rates? 

Time to defibrillation is the most crucial factor for survival in cases of out-of-hospital cardiac arrest (OHCA). The use of drones to deliver a defibrillator has never been clinically evaluated. The aim of this study was to investigate the feasibility of AED delivery using drones in real-world OHCA cases. There are currently no published studies describing the deployment of defibrillators flown to actual sites of suspected cardiac arrest. In this feasibility study, three AED-equipped, remotely controlled drones were used in a controlled airspace in Gothenburg, Sweden, covering approximately 80,000 residents (125 km²). 

With the first permit of its kind in Sweden issued by the Transport Agency, drones conducted flights beyond the pilot’s visual line of sight (BVLOS) to consecutive suspected OHCA cases over a four-month period in 2020. This was as a complement to standard care, ambulances, and emergency services (IVPA). The primary outcome measure was feasibility, defined as the proportion of successful AED deliveries at the suspected OHCA sites. 

The study, published in the European Heart Journal (EHJ) in August 2021, showed that the delivery of a defibrillator using drones was feasible in 11 out of 12 cases (92%). The drone arrived before the ambulance in 64% (7/11) of cases, with a median time saving of 1:52. Additionally, the defibrillator was delivered approximately 10 meters from the location/entrance, increasing the possibility for the dispatcher to instruct bystanders to retrieve the defibrillator. 

The project is ongoing, and a new prospective study began on April 21, 2021, with 5 drones in Västra Götaland. The study includes patients until December 31, 2021. Subsequent studies are planned for 2022 and beyond to assess clinical outcomes, primarily the proportion of cases with drone arrival before the ambulance. The project is led by Andreas Claesson, Jacob Hollenberg, and Leif Svensson. 

Principal Investigator: Anette Nord  
Doctoral Student: Fredrik Byrsell 
Research Question: Can the use of artificial intelligence during ongoing emergency calls increase the identification of cardiac arrest and shorten the time to dispatch life-saving resources? 

Rapid and accurate identification of cardiac arrest is critical for survival. The overall aim of this project is to enable earlier identification of cardiac arrest during ongoing emergency calls, allowing swift dispatch of life-saving resources. Artificial intelligence, in the form of a machine learning model (ML), can be described as a method of programming a computer to independently recognize problems and solve them. In this research project, the ML model is programmed to detect specific parameters during ongoing 112 emergency calls and uses statistical calculations to estimate the likelihood that the call involves a cardiac arrest. 

The ML model was developed by the private company Corti ApS in Denmark and is currently used in the emergency dispatch center of the Capital Region of Denmark (Hovedstaden) in Copenhagen and in Seattle (US). From 2010 to 2020, the model was adapted to analyze spoken Swedish. This technological development occurs in two phases: 

  • Language Training Phase: A total of 100 hours of 112 emergency calls from all categories recorded by SOS Alarm from 2015 and stored by SOS Alarm will be transcribed into written text. These calls and text files are then fed into the ML model solely to train it in the Swedish language. This phase was completed in 2020.
  • Cardiac Arrest Identification Phase: An additional 5,100 cardiac arrest cases reported to the Cardiac Arrest Registry from ambulance services in 2016 will be labeled as “true cardiac arrests.” A prospective study is planned to explore whether the system can help dispatch operators identify cardiac arrest more accurately as well as earlier in the call.

The project is led by Anette Nord, Mattias Ringh, and Andreas Claesson. 

Principal Investigator: Per Nordberg  
Doctoral Students: Emelie Dillenbeck and Thomas Berthelsen  
Research Question: Can early cooling treatment (within minutes) increase survival without brain damage in patients experiencing cardiac arrest, compared to normothermia? 

Every year, about 10,000 people suffer from cardiac arrest in Sweden. The mortality rate is high, and in hospitals, the majority die from severe brain injuries caused by lack of oxygen. Currently, there is no treatment for these brain injuries. Hypothermia (cooling treatment), however, has the potential to protect the brain. Animal studies show that early cooling (within minutes) is crucial, and ideally, cooling should start during the ongoing cardiac arrest. Despite this, previous studies have initiated cooling treatment late, after arrival at the hospital and the intensive care unit, several hours after the cardiac arrest. The effect of this late cooling strategy is uncertain, and there remains a significant knowledge gap regarding whether early cooling, started already at the site of the cardiac arrest, can increase survival with full brain function recovery.

In the PRINCESS2 study, a unique concept is used where cooling treatment is initiated at the site of the cardiac arrest. Prehospital staff use a portable cooling method that begins targeted brain cooling via the nose. Two previous randomized studies (PRINCE and PRINCESS), with a total of 877 cardiac arrest patients, have shown that this concept effectively cools the patient to a protective temperature and has great potential to improve survival with full brain function recovery. The goal of the PRINCESS2 study is to confirm these promising results in a larger study. 

Over 1,000 patients will be included in the study. They will be randomized to either cooling treatment that begins at the site of the cardiac arrest and continues for the first 24 hours in the intensive care unit, or to standard treatment (no cooling, only avoidance of fever). Patients will be followed up after 90 days regarding their neurological recovery. 

PRINCESS2 is led by Per Nordberg and his team and is conducted at approximately 25 centers in Sweden, Germany, Spain, Austria, Belgium, Italy, Slovenia, and Norway.

Principal Investigator: Ludvig Elfvén  
Research Question: Can acute coronary angiography after cardiac arrest improve survival? 

It is currently unclear when coronary angiography (angiography/PCI) should be performed on patients who have regained circulation after cardiac arrest without ST-changes on the first ECG. This ongoing study examines whether acute coronary intervention (within 2 hours) after successful CPR can positively affect survival compared to standard treatment. The pilot phase has been completed and demonstrates high safety and feasibility. Two doctoral students (Elfvén 2020 and Lagerdal 2020) have defended their theses on the concept as a model. The main study is ongoing. This is a collaborative project with Uppsala University and several other hospitals in Sweden. Ludvig Elfvén leads the project. 

Principal Investigator: Jacob Hollenberg  
Doctoral Student: Lis Abazi  
Research Question: Can treatment with a heart-lung machine improve survival in cardiac arrest cases refractory to A-CPR? 

ECMO is essentially a heart and lung machine that oxygenates blood outside the body for a limited period. The method has been proposed as a life-sustaining treatment option in acute conditions like severe respiratory failure, cardiac arrest, and cardiogenic shock. Our data suggest that around 50 patients under 65 years old die annually from refractory ventricular fibrillation in the county of Stockholm. The aim of this project is to demonstrate survival benefits in a prospective study. 

A pilot phase began in Q1 2020, focusing on safety and feasibility. This is logistically a complex project and a large collaboration between the emergency dispatch center, multiple ambulance organizations, Södersjukhuset, Karolinska Solna, Karolinska Institute, and other hospitals in Region Stockholm. No results are available yet. Jacob Hollenberg is the initiator and principal investigator for the project. 

Principal Investigators: Sune Forsberg and Mattias Ringh
Doctoral Students: Malin Albert
Research Question: Can vasopressin and corticosteroids in addition to adrenaline improve survival in patients who suffer cardiac arrest, compared to adrenaline alone? 

In treatment of cardiac arrest where medication is required, adrenaline and cordarone is currently used. Neither adrenaline nor cordarone improve longtime survival or survival with favorable neurological outcome yet is recommended in current guidelines. The drugs vasopressin and corticosteroids have in smaller studies shown improved survival in in-hospital cardiac arrests. More and bigger studies are needed to be able to safely answer the question whether survival can be improved. No serious risks are known in treating patients with these drugs. 

As part of our planned randomized drug study, the treatment will be randomized between standard treatment with only adrenaline and with adrenaline in combination with vasopressin and corticosteroids. Patients in the study will receive at least the same treatment as today. Other care will not be affected during hospitalization. The study is planned to be conducted at 20 hospitals across the country. The work began in 2021 with a pilot phase involving Södersjukhuset, Sahlgrenska Hospital, and Norrtälje. The study is complex to conduct due to patient consent procedures. Three doctoral students are registered to run the study. Sune Forsberg and Mattias Ringh are the principal investigators.

Principal Investigators: Andreas Claesson and Jacob Hollenberg 

According to the WHO, approximately 400,000 people die worldwide each year from drowning accidents, with about 200 drowning deaths and at least 200 serious injuries in Sweden alone. The duration of submersion is critical for the outcome of drowning, and after 10 minutes of submersion, the chances of surviving without severe brain damage are low. 

In Sweden, there is currently no knowledge center dedicated to the scientific evaluation and development of new methods to increase survival in drowning incidents. Drowning is often diagnostically associated with cardiac arrest. Andreas Claesson, a member of the steering group of the Center of Resuscitation Science, is one of the few doctors with a PhD in this field and a world authority on the topic. 

Public statistics from the responsible agency (MSB) are generally based on media reports, and there is lack of deeper knowledge about incidence, causes, and prevention measures to reduce this problem in society over time. A major registry study published in early 2021 described deaths and injuries over a 15-year period and serves as a foundation for future studies and the establishment of a knowledge center. In April 2021, the UN adopted a resolution that all member countries should have a national center for drowning prevention and an action plan for preventing drowning. Sweden currently lacks both.

The primary goal of this planned knowledge center, which will be closely coordinated with the Swedish Lifesaving Society and MSB, includes:

  1. Developing a research track with the aim of establishing a national center with a central database in collaboration with the National Forensic Medicine, the National Board of Health and Welfare, and MSB. This database will serve as a knowledge base for future research and annual reports aimed at reducing drowning-related deaths and injuries in Sweden.
  2. Developing an identification system to be used in the first minutes of drowning incidents. This system could be used by rescue services, lifeguards, swimming pool staff, etc. The system includes a drone and AI technology, with the ambition to develop and clinically test an algorithm integrated into a drone that can autonomously locate a drowning person earlier than is possible today.

Principal Investigators: Therese Djärv, Gabriel Riva, Eva Piscator, Kasper Glerup Lauridsen  PhD Student: Hritul Karim 
Research Question: Can prediction models identify patients who will survive in-hospital cardiac arrest with good neurological function? Can these models be used to reduce decision variability among physicians in Do-Not-Resuscitate (DNR) decisions?   

Only 5-10 percent of patients who die in hospital receive CPR, as many patients in hospitals have an ethical decision not to initiate CPR during a cardiac arrest. A "No CPR" decision is made if CPR would not benefit the patient, if CPR is futile, or if the patient does not want CPR. This decision must be based on medical facts and should be preceded by consultations with the patient and a licensed healthcare professional. Unfortunately, there are currently no scientifically validated models to guide healthcare professionals in these decisions, and consultations are conducted in less than half of the cases. 

This project aims to create a scientific foundation for discussions with patients and implement it into clinical practice. This way we hope to increase the likelihood that decisions align with the patient's goals and values.

Principal Investigators: Therese Djärv and Gabriel Riva 
Doctoral Student: Samuel Bruchfeld  
Research Question: What causes cardiac arrest in hospitals, and what can predict the need for immediate investigations/treatments? 

The majority of cardiac arrests in hospitals are witnessed and patients connected to ECG monitoring. Despite this, little is known about why these patients experience cardiac arrest. The goal is to identify the most common causes of in-hospital cardiac arrest and evaluate the significance of the cause for the patient’s prognosis. With greater knowledge, we can prevent more cardiac arrests, improve treatment during the event, and enhance follow-up care for surviving patients.

Principal Investigators: Therese Djärv, Tomas Kahan, Johan Englund, Araz Rawshani  Doctoral Student: Anna Thoren  
Research Question: Which vital parameters or actions predict cardiac arrest and survival in hospitals? 

Cardiac arrest in hospital is typically preceded by altered vital parameters such as low blood pressure or increased respiratory rate. Most patients are also connected to ECG monitoring, and many are evaluated by the Mobile Intensive Care Group (MIG) before the event. Despite this, cardiac arrests still occur. Currently, we do not know how to better use these parameters to identify those at risk for cardiac arrest, allowing for earlier intervention and potential prevention.

Principal Investigators: Therese Djärv, Martin Jonsson, Elham Hedayati, Christel Hedman  PhD Student: Hanna Hägglund  
Research Question: What factors predict the incidence and survival of cardiac arrest and severe cardiovascular disease in patients with cancer? 

The number of people living with cancer is increasing in today's society. Cancer patients have a higher risk of cardiovascular disease, partly due to the toxic effects of cancer treatments on the heart. Currently, it is unknown which cancer patients are at an increased risk of experiencing cardiac arrest and what their survival outcomes are. Furthermore, this project investigates which factors and cancer treatments contribute to an increased risk of severe cardiovascular disease (MACE) in patients with multiple myeloma, an area that remains largely unexplored.

Principal Investigators: Maria Bruzelius, Therese Djärv, Susanna Larsson, and Joel Ohm  PhD Student: Emma Bendz  
Research Question: What is the association between thromboembolism and cardiac arrest in women of reproductive age? 

Thromboembolism, such as blood clots in the lungs or deep veins of the legs, occurs in young women, and certain medications increase this risk. Some studies have also suggested that thromboembolism may explain why young women experience cardiac arrest. This project aims to map the relationship between thromboembolism, medications, and cardiac arrest. The study is registry-based and utilizes nationwide Swedish health registers.

The Center for Resuscitation Science has contributed to the development of both national and international guidelines for cardiac arrest and first aid. Jacob Hollenberg, Anette Nord, Andreas Claesson, Mattias Ringh, Per Nordberg, and Therese Djärv have all contributed to this international work. Andreas Claesson, along with Jacob Hollenberg and Anette Nord, has overall responsibility for the development of national guidelines and training programs in close collaboration with the Swedish Council for Cardiopulmonary Resuscitation.

Principal Investigators: Gabriel Riva and Akil Awad 
Doctoral Student: Emma Blick Nordkvist  
Research Question: Can early double defibrillation (after 3 failed standard defibrillations) improve survival compared to standard defibrillation? 

 A new method, using two defibrillators for double sequential defibrillation (DSD), has shown promising results in a recently published Canadian study. In that study, DSD was tested after three failed standard defibrillation attempts. However, the method is not yet recommended as routine treatment. 

 This project aims to investigate whether early double defibrillation (before three failed attempts) in out-of-hospital cardiac arrest cases with ventricular fibrillation can improve survival compared to standard defibrillation. As a first step, a pilot study is planned to evaluate the feasibility and safety of early DSD. 

The pilot study is conducted by the Center for Resuscitation Science at Karolinska Institute in collaboration with ambulance services in Alingsås, Lerum, Kungälv, Sahlgrenska University Hospital, and Region Halland. 

More information can be found on the study's website.

Main supervisor: Per Nordberg
Assistant supervisors: Jacob Hollenberg, Martin Jonsson and Rebecka Rubenson Wallin
Doctoral student: Johanna Kämpe
Research question: Which are the risk factors for severe Covid-19 and what are the long-term consequences? 

Some individuals, even if they appear healthy and have few or no known risk factors, can still be severely affected by COVID-19. However, little is known about the underlying causes. Genetic variations may influence disease severity, but the mechanisms are not yet fully understood. Whether the transport of intensive care patients (due to resource shortages) affects outcomes and whether severe COVID-19 has long-term cardiovascular effects are also studied to a lesser extent. 

To address current knowledge gaps, the included studies will investigate: 

  1. The relationship between pre-existing comorbidities, severe COVID-19, and 90-day mortality among younger individuals (<50 years).
  2. Genetic variations and their potential impact on disease severity among ICU-treated COVID-19 patients.
  3. Whether the transport of critically ill intensive care patients due to capacity constraints affects mortality, complication rates, length of hospital stay, and duration of mechanical ventilation.
  4. Whether severe COVID-19 affects cardiovascular morbidity and mortality in a three-year follow-up. 
Keywords:
Anesthesiology and Intensive Care Cardiology and Cardiovascular Disease Out-of-Hospital Cardiac Arrest Resuscitation
Content reviewer:
Jacob Hollenberg
19-03-2025