Perhaps the most common code used in hospitals for signalling a cardiac (heart) emergency, meaning that someone is in need of cardiopulmonary resuscitation (other hospitals will have a similar code; for example, “Code 7” or “Code Yellow”). Those individuals who are expected to respond know who they are, what it means, and what their response is expected to be. It is sometimes said that a patient has been “coded” when a code blue alarm has been sent.