Purpose/Context. Anticipated will is the process by which a patient, in full use of his competences and without any coercion, expresses his preferences about procedures and treatments to be accepted or omitted in case he loses his capacity to decide. In the intensive care unit, emergent actions are performed on critically ill patients, where an advance directive is often not available or is not asked about, a situation that will be decisive at the time of a complication or end-of-life situation. Methodology/Approach. In this reflection article, the way in which the autonomy and the best interest of the patient in critical condition behaves is discussed. It also describes advance directives from their rationale and their spectrum of application in the critically ill patient, in addition to the knowledge and perception that intensivists have about the process. Results/Findings. From the respect for the being and his/her preferences (in the case that it is possible to know them), questions are formulated about what is really the best for the patient according to each particular case, from the principled ethics and from the convergent ethics. Discussion/Conclusions/Contributions. It is necessary to broaden the dissemination of advance directives as patients' rights and as a tool to delimit treatment objectives and their scope in situations that compromise patient autonomy, in health care settings in general and mainly in intensive care units.
