This study focuses on patients who experience out-of-hospital cardiac arrest, a serious medical emergency that occurs when the heart suddenly stops beating outside of a hospital setting. The research examines the use of epinephrine, also known as adrenaline, which is a medication commonly used during cardiac emergencies to help restart the heart.

The purpose of this study is to compare two different doses of epinephrine in treating cardiac arrest patients. The study will test whether a lower dose (0.5 mg) works better than the standard dose (1 mg) in helping patients survive with good brain function. The medication will be given as a solution for injection through a vein during emergency treatment by medical teams.

During the study, patients will be randomly assigned to receive either the lower or standard dose of epinephrine. Neither the patients nor the medical team will know which dose is being given. The treatment will be provided as part of the emergency care when medical teams arrive to help someone experiencing cardiac arrest. The study will monitor how well patients recover over 28 days after their cardiac arrest.