[The protocols and the medical decision: evidences based in experience or existence?].

The main purpose of this study is to understand the concepts and interests concerning the transformation of the practical quotidian knowledge produced by experience into probabilistic epistemological models. The object is the argumentation and practices surrounding consensus-forming which knowledge criteria are valid for diagnostic and therapeutic decisions. Our starting point is Ludwik Fleck's work, which states that facts are not objectively given but collectively and contingently created so as to adjust themselves to a style of thought. Our research strategy was an ethnographic observation of medical rounds and clinical meetings in a cardiology ICU in Rio de Janeiro. The analysis was based on the works of Knorr-Cetina (transepistemic arenas) and Perelman's argumentation theory. It revealed the consolidation of a tendency to incorporate explicit cost-benefit criteria and the interests of different agents such as doctors, government and the medical-industrial complex in the introduction of protocols. The observation demonstrated an ambivalent use: protocols/scientific studies and clinical experience as well. A certain skepticism of the clinicians and their relative inability in the usage of the analytic tools of the epidemiological thought style were particularly remarkable.