Epinephrine may save the heart, but not the brain, says study

Using the drug epinephrine during a cardiac arrest may do more harm than good, says a new study.

Researchers at the Kyushu University School of Medicine in Japan looked at the medical records of more than 400,000 cardiac arrest patients over a three-year period and found that while the drug may be effective in the short-term, it may not improve survival outcomes in the long-term.

According to the report, patients who received doses of the adrenaline-like drug in the ambulance were three times more likely to regain a heartbeat before they reached the hospital, when compared to those who did not get the drug.

But patients who got the drug were about half as likely to be alive one month after the incident; and only a quarter of those that survived were able to function normally.

Although epinephine is the standard of care for treating out-of-hospital cardiac arrests, some doctors are not surprised at the study's findings.

"Community studies have shown that things like bystander CPR and public-access defibrillators have been successful, and that [advanced life support] interventions are not," said Dr. Alex Isakov, director of Emory University's Section of Pre-Hospital and Disaster Medcine. "This study just confirms what we've believed to be true for some time."

Study authors say in the paper that one possible reason for the negative outcomes associated with epinephrine may be due to the very nature of the drug – it causes veins around the body to clamp down and shunt blood towards the heart to keep it fueled.

Although that's the intended effect of the drug, that clamping down of vessels may starve other parts of the body that need blood for long-term survival. In short, epinephrine may save the heart, but not the brain or the rest of the body, they say.

Although the drug has been used regularly since the 1960s, very few good studies have been done comparing epinephrine to a placebo , because withholding a drug known to improve short-term survival would be considered unethical.

Isakov says the latest report could change that.

"This large study - which suggests not only that there's no improvement in cardiac arrest survival with epinephrine, but that perhaps those who did not receive the drug had better outcomes - might open the door to a placebo controlled trial," said Isakov.

He also says this study should be cause to focus on things we know help improve survival rates.

"Bystander CPR and timely defibrillation are known to improve outcomes," he said. "For communities that want to improve out of hospital cardiac arrest survival, that's what they should focus on."