Epinephrine Can Help Restart Heart, But At What Cost

October 9th, 2016

PARIS – Administering epinephrine to restart the heart may not be the best way to save lives when patients are in cardiac arrest, according to a new French study.

The report, published recently in the Journal of the American College of Cardiology, notes that administering epinephrine can increase the overall likelihood of death or debilitating brain damage.

The research from the Parisian Cardiovascular Research Center provides new data in the ongoing debate about the risks and benefits of using epinephrine to treat cardiac arrest. International guidelines currently recommend administering 1 milligram of epinephrine every 3-5 minutes during resuscitation.

"The role of epinephrine is more and more questionable in cardiac arrest," said lead author Florence Dumas, MD, PhD. "We need to constantly assess our procedures and protocols to make sure that the use of epinephrine is effective and done at the correct time."

While administering epinephrine to patients in cardiac arrest improves the return of spontaneous circulation (ROSC), it also harms patients' chances of surviving past the post-resuscitation period with brain function intact, according to the report.

The researchers analyzed hospital records for more than 1,500 patients – all of whom had suffered out-of-hospital cardiac arrest, been resuscitated and achieved ROSC – admitted to a large Parisian hospital over a 12-year period. Almost three-quarters of the patients had received at least one dose of epinephrine.

Results indicate that 63% of patients who did not receive epinephrine achieved the primary outcome, defined as discharge from the hospital with normal or only moderately compromised brain functioning. On the other hand, only 19% of patients who received epinephrine met that goal.

In addition, patients receiving higher doses of epinephrine fared worse than those with lower doses. Compared to patients resuscitated without epinephrine, those receiving 1-milligram doses were 52% more likely to have a bad outcome while those receiving 5-milligram or larger doses were 77% more likely to have a bad outcome, according to the study.

Patients who had not received epinephrine were generally younger and more likely to have been near a witness when they collapsed, but statistical methods were used to account for the differences.

Another factor was found to be timing, with patients receiving epinephrine in the later stages of resuscitation faring worse than those who got their first epinephrine dose shortly after collapsing.

Post-resuscitation medical treatments, such as techniques to cool the body to reduce tissue damage or interventions to restore the flow of blood through blocked arteries, had little effect on epinephrine’s adverse outcomes, study authors report.

"It's very difficult, because epinephrine at a low dose seems to have a good impact in the first few minutes, but appears more harmful if used later," said Dumas, who did not suggest an immediate change in guidelines. "It would be dangerous to completely incriminate this drug, because it may well be helpful for certain patients under certain circumstances. This is one more study that points strongly to the need to study epinephrine further in animals and in randomized trials."

The authors called for studies on other drugs and drug combinations that could offer safer alternatives to epinephrine during cardiac arrest.