From a study by Ullmann Y, Fodor L, Schwarzberg I, Carmi N, Ullmann A, and Ramon Y:
BACKGROUND: Little information is available about the effect of music on the operating room (OR) staff. PURPOSE: The objective of this study was to evaluate the perception of the influence of music on physicians and nurses working in the OR. METHODS: A questionnaire was designed and 250 copies were distributed to the doctors and nurses working in the OR at three hospitals. One hundred and seventy-one returned the completed questionnaire and were included in this study. RESULTS: 63% of the participants listen to music on a regular basis in the OR. Classical music is the most requested [emphasis added] (58%) and most of the responders do not choose the type of music according to the type of the procedure. In our study, the nurses were more likely to listen to music and the willingness is higher among the female responders. The desired volume is lower as age increases and 78.9% of the participants claimed that music in the OR makes them calmer and more efficient. CONCLUSION: According to our study, music has a positive effect on the staff working in the operating rooms [emphasis added].
So classical music in the OR leads to calmer and more efficient staff, especially nurses. What about putting it in the entire hospital? We already know that the better nursing care you receive, the better your outcome is.