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Best treatment for cardiac arrest – new international study will provide answers

cardiopulmonary rescue on person with cardiac arrest. photo.
Picture: iStock/Chalabala.

The guidelines governing the treatment of sudden cardiac arrest exhibit variation across different nations, with treatment strategies often resting on a limited evidential foundation. A randomized international study is underway poised to address some of the most pivotal questions. Encompassing a cohort of 3,500 patients, this study aims to scrutinize the impact of different fever treatments, controlling blood pressure and sedation on outcomes of sudden cardiac arrest.

Every year around 700,000 people in Europe and USA alone suffer sudden out-of-hospital cardiac arrest, a figure that considerably increases when those affected while hospitalised are included. Early measures such as cardiopulmonary resuscitation are crucial for saving lives but as few as one in ten people survive. Patients who survive cardiac arrest generally need intensive care and often suffer permanent brain damage.  

As we will include such a large group of patients, we are taking the opportunity to examine several research questions in the same study

“The evidence is weak concerning which measures provide the best effect and today’s treatment is based on uncertain data,” says Niklas Nielsen, professor of anesthesiology and intensive care at Lund University and intensive care physician at Helsingborg Hospital, Sweden. He led the targeted temperature management (TTM) studies that were published in the New England Journal of Medicine in 2013 and 2021, which showed that cooling to 33 degrees after cardiac arrest did not improve survival chances. The results of the studies have influenced guidelines around the world.

Now, the research is being taken one step further. In an extensive multicentre clinical study, the researchers will examine the effect of:

  • sedation – deep or minimal
  • fever treatment – with or without cooling equipment
  • blood pressure treatment – lower or higher blood pressure

The ongoing study will include a total of 3,500 cardiac arrest patients, who are randomly allocated to one of three different treatments. The first patient was included in autumn 2023 and the researchers estimate that between 60 to 80 hospitals around the world will be involved. The aim is to obtain a better scientific basis for which treatment methods deliver the biggest benefit for the patient.  

“We examine whether cooling has an effect on fever, if moderate or high blood pressure is optimal and whether controlled sedation of the patient can affect survival chances and brain damage,” says Niklas Nielsen, who is leading the STEPCARE study.

The treatments are already in use, but guidelines differ internationally. Even though examining already existing treatments presents certain challenges, it is important that there is a high level of evidence for the treatments offered in healthcare.

“As we will include such a large group of patients, we are taking the opportunity to examine several research questions in the same study,” says Niklas Nielsen.

Brain damage after cardiac arrest

One of the sub-studies for STEPCARE is led by Marion Moseby Knappe, researcher at Center for Cardiac Arrest at Lund University and assistant chief physician at Rehabilitation Medicine, Skåne University Hospital. 
The focus is on assessing brain damage after cardiac arrest, as this forms the basis for decisions on continued treatment.

“It is crucial at an early stage to identify patients for whom continued intensive care can save lives. At the same time, we also need to find ways to see which patients with severe brain damage will never wake up again and where continued treatment does not benefit the patient,” says Marion Moseby Knappe, who received the Swedish Research Council’s starting grant to conduct this part of the study.

The aim of the sub-study led by Marion Moseby Knappe is to examine whether it is possible to assess patient prognosis more reliably by combining image diagnostics, brain damage markers in the blood and measurements from neurophysiological examinations 24 hours after cardiac arrest.
“We want to be able to give the right patients the right treatment while avoiding care that does not lead to an improvement,” explains Marion Moseby Knappe.
The patients in STEPCARE will be monitored for six months after cardiac arrest. The researchers expect to compile the first results in 2027.


STEPCARE ( is an international randomised study that includes cardiac arrest patients over the age of 18. The study is led by Niklas Nielsen, professor at Lund University, along with an international steering group and will include 3,500 cardiac arrest patients and some 80 hospitals in close to 20 countries around the world. The study’s primary results are survival rates after 180 days, but neurological function and health-related quality of life are also examined. The funding bodies for the study include the Swedish Research Council, Region Skåne, ALF, Gorthon Foundation, Academy of Finland, and research funds in Australia and New Zealand.

The TTM studies
The targeted temperature management study TTM2 was led by Niklas Nielsen, Lund University, Helsingborg Hospital, along with an international steering group. Researchers and physicians from 61 hospitals in 14 countries took part. The results of the study showed that cooling did not reduce the mortality rate among unconscious patients with suspected cardiac arrest.

TTM2 was a follow up to the TTM1 study published in the New England Journal of Medicine in 2013. The study included 950 patients and the researchers saw that there was no benefit from cooling patients down to 33 degrees, compared with maintaining body temperature at 36 degrees.
TTM2 article Juni 2021


portrait niklas nielsen. photo.

Niklas Nielsen, MD, PhD,  Professor of Anesthesiology and Intensive Care at Lund University and Senior consultant Helsingborg Hospital, Sweden.
Profile in Lund University research portal

porträtt marion moseby knappe. foto.

Marion Moseby Knappe, MD, PhD, researcher at Center for Cardiac Arrest at Lund University and assistant chief physician at Rehabilitation Medicine, Skåne University Hospital, Sweden.
Profile in Lund University research portal