The intensive care units is of the main components of modern healthcare systems. Formally, its aim is to offer the critically ill health care fit to their needs; ensuring that this health care is appropriate, sustainable, ethical and respectful of their autonomy. Intensive medicine is a cross-sectional specialty that encompasses a broad spectrum of pathologies in their most severe condition, and specifically has as its foundation the practice of comprehensive care of the patient with organ dysfunction and susceptible to recovery. Although critically ill patients are a heterogeneous population, they have in common the need for a high level of care, often requiring the use of high technology, specific procedures for the support of organ dysfunction and the collaboration of other medical and surgical specialties for their management and treatment.

Since their origins in the late 1950s, intensive care units have been adapting to the changes arising from the best scientific evidence. In the late 1990s and early 2000s, there were some successful clinical trials published that had tested alternative management strategies in the ICU.

Mechanical ventilation is an intervention that defines the critical care specialty. Between 1970 and the 1990s, the management focused on normalizing arterial blood gas with aggressive mechanical ventilation. Over the ensuing decades, it became apparent that performing positive pressure ventilation worsened lung injury. The pivotal moment in the mechanical ventilation story would be the low versus high tidal volume trial. This trial shifted the focus away from normalizing gas exchange to reducing harm with mechanical ventilation. Further, it paved way for further trials testing ventilation interventions (PEEP strategy, prone position ventilation) and nonventilation interventions (neuromuscular blockade, corticosteroids, inhaled nitric oxide, extracorporeal gas exchange) in critically ill patients.

That evidence-based intensive care medicine has undoubtedly had an influence on the outcome of critically ill patients, in general, and, particularly, of patients requiring mechanical ventilation. Temporal changes in mortality over the time have been scarcely reported for patients admitted to intensive care unit.

Objective of this study is to estimate the changes over the time in several outcomes in the patients admitted to an 18-beds medical-surgical intensive care unit from 1991 (year of start of activity) to 2026

Inclusion Criteria:

• Patients admitted to intensive care unit

Exclusion Criteria:

• None

Patients who required a admission to intensive care unit