A modern operating room, courtesy Dr. Piotr Bodzek, via Wikipedia
The operating room is a specially sterilized room in the hospital designed for surgery. It is frequently cleaned with antiseptics and the materials used it its construction are specifically chosen for ease of cleaning. This is to attempt to ensure that infection is as unlikely as possible. The air is specially filtered to ensure outside air is kept out and that dust in the room is continuously suppressed. It also has special lighting and equipment for anesthesia and monitoring vital signs.
Prior to the development of the modern operating room, the most likely cause of death after surgery was secondary infection. Most infections were carried by airborne particles, and surgery rooms themselves were often made out of materials that harboured organic materials, such as wood. They often were large rooms to allow students to sit in, but made no attempt to separate observers from the patient. Modern operating rooms are now made out of steel, glass, concrete and plaster, and are as small as possible to accommodate the surgical team. In order to allow students and other physicians to observe, they have observation galleries that are separated by glass panels.
At most hospitals, the control over scheduling of the operating rooms is the responsibility of the Chief Surgeon as part of his or her administrative duties.