Prospective, knowledge based clinical risk analysis: The OPT-model

5%-10% of all medical procedures are erroneous. It is estimated that about 10.000 persons in Germany die due to errors in medical interventions. The clinical risk management analyses the reasons for errors and avoidable events, in most cases retrospectively. Approaches such as Hazards & Operability Study (HAZOP) are applied routinely in technical environments. In a quite small number of rather medical specific procedures especially in laboratories the risk management demands HAZOP. In the clinical domain this approach is not used due to the difficulties to describe medical processes and task with all different kinds of properties.