This work proposed: 1) to record all the anaesthetic information in the SYSRES system, 2) to carry out a global numerical evaluation of the surgical risks in the form of a coefficient (CORI) defining a probability of complications thanks to a table established from several hundred case-files. This method has several purposes: the carrying-out of very quick summaries of case-files, and of statistical studies, several of which could be used as a basis in scientific work and, most of all, allow an increase in the safety of the patients.