Although the practice of overlapping surgeries, in which one surgeon, assisted by a surgical team, performs more than one procedure at a time by moving between operating rooms, has raised concerns, an analysis by researchers in the Department of Health Care Policy in the Blavatnik Institute at HMS has found that such surgeries create no greater risk for complications or in-hospital patient deaths than most single surgeries do. Exceptions are for high-risk patients and those undergoing coronary bypass surgery, where slight elevations in mortality and complications were found. Procedure duration, however, was notably longer for overlapping surgeries: 204 minutes, on average, compared with 173 minutes.