Noise in operating rooms (ORs), defined as any unwanted sound impeding on normal hearing, can be grouped into two categories: equipment-related noise and staff-created noise. Equipment-related noise can come from anesthesia equipment and alarms, suction devices, or surgical instruments such as cautery devices, dissection tools, and drills. Staff-created noise can come from opening and closing doors, conversations, overhead pages, and music. All of these noise sources contribute to the average ambient noise in ORs, which is 65 dBA with peak levels reaching120 dBA.