The study included 36 patients at Yale-New Haven Hospital and 54 patients at the American University of Beirut Medical Center. The subjects wore headphones and were randomly assigned to hear music they liked, white noise or to wear no headphones and be exposed to operating room noise. Dropping a surgical instrument into a bowl in the operating room can produce noise levels of up to 80 decibels, which is considered very loud to uncomfortably loud.
What they found is that blocking the sounds of the operating room with white noise did not decrease sedative requirements of listening to operating room sounds. Playing music did reduce the need for sedatives during surgery.
“Doctors and patients should both note that music can be used to supplement sedation in the operating room,” Kain said.

From a Yale University Press Release