The Critical Hour is a medical reality TV show about real medical emergencies. Similar in format to the TV show COPS, it is shown in the United States by the Discovery Communications's Discovery Health Channel network. The name "Critical Hour" refers to the fact that in many cases, such as heart attacks, automobile accidents, diabetic comas, overdoses, and other emergencies, medical care for patients during the first hour after the emergency plays a critical role in the patient's outcome, because survival rate for a trauma patient goes down significantly if initial care is not given within the first hour. For this reason, the initial 60 minutes following a traumatic incident is often called the critical hour in emergency medicine parlance. It is more commonly known as the "Golden Hour Concept". The show first aired in 2003. Early episodes of the series took place in Columbus, Ohio, New Orleans, Louisiana, and Oklahoma City, Oklahoma, among other places. A new set of episodes was shot in 2004 and 2005, centered around two cities and three trauma centers: Baltimore, Maryland and Toronto, Ontario, Canada. The former shows were a decidedly different format, with a running timeclock on the patients as they made their way through the initial entrance into the trauma system, while the latter episodes tend to transition between patients' stories, following a smaller set of patient stories from beginning to end throughout the episode. A standalone show, Chopper Rescue, a documentary about flight paramedics in Los Angeles, California, was added to the rotation under the "Critical Hour" umbrella title in 2005. Production continued on the show in 2006, this time centered exclusively on the two Toronto-area hospitals, though the Baltimore Shock Trauma episodes continue to air in reruns periodically.