Mortality risk change as a measure of perioperative quality of care in cardiac surgery

Heart surgery carries a risk of death that can be calculated before the operation. This risk is dependent on patient factors (such as age and illnesses) and the operation itself. After heart surgery, all patients go to the intensive care unit (ICU). Events that occur intraoperatively affect how unwell they are in ICU, and their postoperative risk of death. If the risk goes up, this suggests performance may have been poorer in the operation. In this thesis we develop and validate risk change as a quality measure.