[From evidence-based medicine to shared decision making: how to manage uncertainty in clinical practice.].

In healthcare, uncertainty, far from being an exceptional event, is always present. The concept has been defined as the inability to decide, caused by a subjective perception of ignorance, a meta-ignorance. Ignorance may be seen as unacceptable in the context of healthcare, which seems to require certainties, hard evidence that allow exact predictions, and consequent professional decisions. For this reason, the professional who has to make decisions can be led to assume attitudes of aversion or denial of uncertainty, and to seek refuge in false certainties. In this article, we review the theoretical debate of the past decades and the current evidence around the management of uncertainty in clinical practice, especially in the primary care consultation. We argue that clinical situations can be represented as constituted by a core of risk, whit a known probability of the occurrence of an outcome. This known risk core is surrounded by a cloud of uncertainty, the wider the more the clinical information is vague and inaccurate. This cloud of uncertainty must be taken into account, since it significantly influences the probability assessments within the known risk core. Healthcare professionals can face clinical situations best by assuming an "ecological" attitude, broadening their perspectives from the disease to the patient and from the patient to his context, being able to use both, analytical decision models and more intuitive ones. We outline strategies that are particularly useful in making decisions in situations of uncertainty, such as the fast and frugal heuristics, including diagnostic and therapeutic strategies such as safety netting and the test of time, and those that use instinctive sensations in a complementary way (gut feelings). Furthermore, we outline the importance, in the management of clinical uncertainty, of involving patients in the decision-making process. This for two reasons. One is ethical: patients have always the right to be involved. The other is practical: taking patients' preferences into account improves the clinical reasoning. The higher the uncertainty, the higher the need of patients' involvement in the decision. Finally, we conclude the article by showing how the communication of uncertainty to patients favors the construction and maintenance of a good doctor-patient relationship, based on responsibility, trust and respect.