An adverse event (AE) is defined as unintended injury or complication, which results in disability, death or prolongation of hospital stay, and is caused by healthcare management (including omissions) rather than the patient's disease. Retrospective record reviews in several countries have shown that 2,9% to 16,6% of patients in acute hospitals experience one or more AEs. A patient with an AE may require a higher level of care. Although all AEs are important, preventable AEs that result in an upgraded level of patient care are of particular concern. In this study it's defined as an unplanned admission to intensive care unit (ICU) or a Mobile Emergency Team (MET) intervention. The objectives of this study are to determine the incidence of (preventable) adverse events requiring ICU admission or MET intervention and to assess the level of harm of each AE.