[Biomedical and clinimetric approaches in determining the causes of perioperative risk: developing a German ASA classification].

Perioperative risk research with biomedical (biochemical, physiological) methods must grow up as a main topic in surgical research. However, operative risk has also to be analysed with methods of clinimetrics, such as formal (objective) decision making and epidemiology. Only by this way a convincing practical dimension is added to basic scientific statements. ASA-classification of the preoperative physical status is a global index for estimating the operative risk. It contains objective findings, subjective impressions and the final clinical judgement. For this reason it is so flexible. For a multicentre trial on perioperative risk and histamine an empirical index was constructed using both the ASA-classification and the Mannheim-Munich risk check list.