Patterns of use of an emergency department-based observation unit.

Emergency department (ED)-based observation units are becoming increasingly used for the assessment and treatment of patients who may not require inpatient management or monitoring. This is a retrospective study of 5,714 patients seen in an ED observation unit from October 16, 1996 through July 12, 2000. Of the 5,714 patients seen in the observation unit, 4,191 were discharged and 1,314 were admitted.