Each year, about four million people around the world suffer a sudden cardiac arrest. Many of them are taken to intensive care while unconscious.
Doctors often face a difficult question: will the patient wake up and recover, or is the brain damage too severe? Now, researchers at Lund University in Sweden have found that a simple blood test may help answer that question more clearly.
This new study, published in The Lancet Respiratory Medicine, looked at blood biomarkers—substances in the blood that can show brain damage. The goal was to find out which ones are best at predicting whether a patient will recover after cardiac arrest.
The study involved 24 hospitals in Europe and included 819 adult patients. Most of the patients were men. Blood samples were taken at different times: when they arrived at the hospital, and then again at 24, 48, and 72 hours later. All the samples were tested using the same equipment to keep the results accurate.
The researchers compared four different brain damage biomarkers in the blood. Two of these—neuron-specific enolase and S-100 protein—are already used in hospitals. But the study found that they don’t always give reliable results after cardiac arrest.
The most promising biomarker in the study was called neurofilament light, or NFL. It was already being used to help diagnose other brain diseases, such as multiple sclerosis. In this study, NFL correctly predicted patient outcomes in 92% of cases, six months after the cardiac arrest. That’s a very strong result.
NFL worked better than the other three biomarkers at telling the difference between patients with serious brain damage and those with less damage. It could even give answers as early as 24 hours after the heart stopped. On top of that, NFL is more stable in the blood, which makes testing easier and more reliable.
Another promising biomarker was GFAP, which also performed better than the biomarkers currently used in hospitals. But NFL still came out on top.
Dr. Marion Moseby Knappe, one of the researchers, explained that NFL helps doctors get a clearer picture early on, so they can plan care more effectively.
However, she and the other researchers stress that the blood test alone should not be the only factor in deciding whether to continue or stop intensive care. Doctors also need to look at brain scans and other tests before making such a serious decision.
Professor Niklas Nielsen, who led the study, said that these findings are important because they help predict whether a patient is likely to wake up after a cardiac arrest.
If there’s hope for recovery, care can continue. But if the chances of meaningful recovery are extremely low, doctors and families can consider other options, including palliative care.
This study was part of a larger project called the TTM2 trial, which also tested whether cooling the body after cardiac arrest helps improve outcomes. That earlier study showed no real benefit from cooling the body, and as a result, it is no longer recommended in global treatment guidelines.
This new research gives hope that in the future, a simple blood test could guide doctors and families through some of the toughest decisions in medicine, with more confidence and care.
If you care about heart health, please read studies about how eating eggs can help reduce heart disease risk, and Vitamin K2 could help reduce heart disease risk.
For more information about heart health, please see recent studies about how to remove plaques that cause heart attacks, and results showing a new way to prevent heart attacks, strokes.
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