Anne van Dalen

12 I General Introduction RATIONALE In 1991, the Harvard Medical Practice study found that serious adverse events occurred in 3.7% of the hospitalizations (30121 patient records from 51 New York hospitals). Of these adverse events, 58%were attributable to error (i.e. preventable) and of this fraction, 13.6% resulted in death. 1 In 2000, the American Institute of Medicine’s Committee on Quality of Healthcare published the To Err Is Human report with the main theme “How can we learn from our mistakes?” Only following this report, patient safety became a focal point for reduction of preventable errors in healthcare. 2,3 Since then, healthcare is increasingly focusing on improving safety and quality, resulting in an increased number of studies reporting on adverse events. 3-6 Nearly two decades after this notorious report, the World Health Organisation (WHO) showed data from European Union Member States, consistently suggesting that medical errors and healthcare related events occur in 8% to 12% of hospitalizations. Both a Dutch and Canadian study confirmed that a majority of the adverse events were related to surgical procedures. 7,8 Studies originating from different kinds of developed countries have showed that 14.4% of surgical patients experience adverse events, and more than one third (37.9%) of all surgical adverse events were regarded as potentially preventable. 9 On top of that, Makary et al. suggested that medical error is even the third leading cause of death in the United States. 10 Despite insights resulting from before mentioned studies and efforts aimed at improving surgical patient safety, the incidence of preventable in-hospital medical errors is still too high. The delivery of safe surgical care is however extremely complex. The WHO has therefore made the reduction of surgical errors one of its primary goals. 6 By now, multiple factors have been identified that may influence patient safety and surgical outcome. These may include the surgical team, social interactions, technology, organizational andenvironmental factors, patientcharacteristics, andthecomplexityof the procedure itself. 11 Human factor failures, such as teamwork, communication, organization and distractions have been identified as major underlying causes for surgical adverse events. 12-14 Subsequently, the first steps towards preventing those adverse events should be about acknowledging, analysing, and understanding common error-event patterns. 15,16 For this, insights from actual situations within the environment are needed. The use of