**Discover In-Hospital Cardiac Arrest Study** The Discover In-Hospital Cardiac Arrest (IHCA) study is a research project taking place across multiple hospitals. It aims to understand how different hospitals care for patients after they have a cardiac arrest, which means their heart stops working properly while they are in the hospital. The study looks at how temperature control and predictions about patient recovery are handled. It also examines the differences in how CPR (cardiopulmonary resuscitation, a life-saving technique) is performed. **Key Points:** - **Study Duration:** The study involves observing hospital practices, with no specific treatment given to participants. - **Eligibility:** Adults who had a cardiac arrest while in the hospital and either regained a pulse for more than 20 minutes or were placed on a heart-lung machine during CPR. - **Exclusions:** Those who had a cardiac arrest outside the hospital, in the operating room, or during recovery from anesthesia, or who had a very brief arrest. Participants are not required to make extra visits or undergo any treatments specific to the study. There is no compensation mentioned for participation.