"Trauma Center, known in Japan as Chōshittō Kadukeusu (超執刀カドゥケウス, lit. "Super Surgical Operation Caduceus"), is a series of simulation/visual novel games in which players assume the role of a surgeon in a fictional hospital setting to strive to save their patients from a pathological condition such as disease or injury using surgical instruments, suturing and the "Healing Touch", a fictional superhuman ability which, according to Greek mythology, descended from Asclepius, the god of medicine. A recurring theme throughout the series is the protagonist's trials of treating bioterrorism victims. These games are designed to make use of the Nintendo DS' touch screen and the Wii's Motion sensing and pointing features, being exclusively released on those systems.
The first, second and fourth games feature many of the same characters, and are focused around Dr. Derek Stiles. The third game, set ten years after the end of the first game, introduces new protagonists, Markus Vaughn and Valerie Blaylock, as well as other characters. The fifth game focuses on six playable characters rather than an individual doctor, and has only one main returning character, Naomi Kimishima of Trauma Center: Second Opinion."
Source: Wikipedia, "Trauma_Center_(series)", available under the CC-BY-SA License.