[Medical error: adverse events].

At the present time, care the patients safety during across the process of health is a priority target and determine the urgent necessity, to guarantee the satisfaction of their health needs, on best conditions as possible as it is, without complications for adverse events occurring in the medical attention. This paper purpose definition of different concepts like medical error, medical criteria, adverse and sentinel event, in order to define these concepts. Also try to show the sequence of events for a correct or incorrect medical decision, the consequent mistake and the possibility to produce an adverse event, with patient's damage. An important goal is that the medical practice is immersing in a biological paradigm, define like unpredictable, suitable, reactive and creative; very different to the exact science that has a predictable and structured paradigm, supported in mathematical rules. In the medical practice, each patient is an inedited situation and required all the knowledge, skills and experience in order to satisfy specific health needs, particularly in critical moments. The way for protect from the occurrence of medical error include the clinical practices guidelines, evidence-based medicine, the maintenance of professional competences by the continuous training, the close medical-patient relationship, integral approach of the illness and scrupulous data at the clinical record. In consequence, very often medical errors produce adverse events with damage of patients, or sentinel events with serious consequences of health, integrity or patient's life. Is important to say that the adverse events could be appear even without a medical error, just for failures in structural and systems issues, including resources and it's maintaining, organizational variables, communication, human resources, training programs, process without standardization, failures an supervision or control phases. This paper shows current adverse and sentinel events, and distinguish between the possibility of its measurement with good and standardized register systems.