[Patients' classification systems as management tools at intensive care units].

This study is a theoretical approach to different care and management measuring tools used to determine the severity of patients' illnesses, to quantify patients' care demands, and to estimate the actual need for Nursing professionals and the costs of intensive care, which makes them management facilitators. This article presents several measuring tools that are focused on the classification of patients at Intensive Care Units (ICUs) considering both the severity of illnesses and the Nursing staff's workload. Facilities and difficulties inherent to the application of these instruments are discussed.