Patient safety increasingly depends on health professionals' ability to deal with the technological, organisational and social complexity of their working environment. The operating room (OR) is such a complex dynamic environment, not just because of the increasing use of technology, such as information technology (IT), monitoring and surgical devices to assist surgical procedures, but also because of less obvious factors, such as an increasing number of comorbidities per patient and the pressure to increase productivity and efficiency. Although many efforts have been made over the years to improve patient safety in the OR, considerable avoidable harm to patients still occurs in the operative process.