Landmark trial likely to change the way cardiac arrest has been treated in the UK for more than half a century

A treatment given to thousands of people who suffer cardiac arrest in Britain every year nearly doubles the risk of permanent brain damage and only marginally improves the chances of survival, a landmark study has found.

More than 30,000 people have cardiac arrests – where the heart stops beating – annually in the UK. More than half receive shots of adrenaline alongside other interventions that are designed to restart the heart. In most cases the attacks are still fatal, with fewer than 10% of patients surviving to be discharged from hospital.

In a study of more than 8,000 people across Britain, doctors found that adrenaline shots increased the survival rate of patients by less than 1%, but nearly doubled the risk of serious brain damage. Nearly a third of survivors who received adrenaline ended up in a vegetative state or were unable to walk and look after themselves, compared with 18% of survivors who had a placebo instead.

These results will have a major impact on the way cardiac arrests are treated around the world Nilesh Samani, medical director of the British Heart Foundation

“What we’ve shown is that adrenaline can restart the heart but it is no good for the brain,” said study leader Gavin Perkins, a professor of critical care medicine at the University of Warwick and a consultant physician at Heart of England NHS Foundation Trust.

The practice of giving adrenaline to people who suffer cardiac arrest has been the standard of care in the UK for more than half a century. Under guidelines set by the Resuscitation Council UK, adrenaline is given to people who fail to respond to cardiopulmonary resuscitation (CPR) or defibrillation immediately following cardiac arrest.

“Make no mistake, the results of this landmark trial will change the way people are treated if, unfortunately, their heart should stop,” said David Nunan, a senior researcher at the University of Oxford Centre for Evidence Based Medicine, who was not involved in the study. “Until now, everyone who’s been eligible to receive adrenaline would have been given it without question. That can no longer be the case.”

In the latest trial, paramedics in five regions of the UK were given packets of syringes pre-filled with either adrenaline or a placebo to use if they encountered people in cardiac arrest. If initial attempts at resuscitation by CPR or defibrillation failed, the paramedics were instructed to administer the fluid in the syringes.

The paramedics did not know whether they were giving patients adrenaline or a harmless salt solution. People living in the areas where the trial, named Paramedic2, was conducted were told about the study and given the option to wear “no study” bracelets if they did not wish to take part.

It is clear that bystander CPR is more effective than adrenaline in saving lives Tim Chico, professor of cardiovascular medicine

Of 4,012 patients treated with adrenaline, 130 were still alive after 30 days, compared with 94 of the 3,995 patients given a placebo. However, of the 128 patients who had adrenaline and survived long enough to be discharged from hospital, 40 had severe brain damage, compared with 17 out of 91 survivors who had the placebo.

“These results will have a major impact on the way cardiac arrests are treated around the world,” said Nilesh Samani, medical director of the British Heart Foundation and a professor of cardiology at the University of Leicester. “Using adrenaline to treat people after a cardiac arrest was based on sound reasoning, but not on robust evidence.”

Jonathan Wyllie, president of Resuscitation Council UK and a professor of neonatology and paediatrics at Durham University, said it was a “groundbreaking” study. “I would absolutely want this evidence to be taken into account for future guidelines,” he said. “If I ever require resuscitation, I hope it is based on evidence such as this rather than merely the opinion of experts.”

Tim Chico, professor of cardiovascular medicine at the University of Sheffield, who was not involved in the work added: “I hope people reading about this study are inspired to learn how to do CPR, because it is clear that bystander CPR is more effective than adrenaline in saving lives.”

The study is published in the New England Journal of Medicine.