http://www.newsweek.com/common-treatment-cardiac-arrest-causes-brain-damage-adrenaline-1038144

When a patient’s heart stops beating, a shot of adrenaline is a last-resort treatment that doctors use to wake the vital organ back up. It’s a routine procedure in emergency rooms across the country, but new research is now questioning the safety and effectiveness of this common intervention.

Adrenaline increases blood flow to the heart and increases the chance of restoring a heartbeat. However, it also reduces blood flow in the tiny small blood vessels in the brain, which may cause brain damage. In a study published on Wednesday in the New England Journal of Medicine, researchers in the U.K found that a third of cardiac arrest survivors who received adrenaline ended up in a vegetative state or were unable to walk and care for themselves, compared with 18 percent of survivors who were given a placebo.