Running title (<50 characters): ICU organization and Acute Lung Injury

Rationale: Prior studies supported an association between ICU organizational model or staffing patterns and outcome in critically ill patients. Objective: To examine the association of closed versus open models with patient mortality across adult ICUs in King County (WA). Methods: Cohort study of patients with acute lung injury (ALI). Measurements and Main Results: ICU structure, organization, and patient care practices were assessed using self-administered mail questionnaires completed by the medical director and nurse manager. We defined closed ICUs as units that required patient transfer to or mandatory patient comanagement by an intensivist and open ICUs as those relying on other organizational models. Outcomes were obtained from the King County Lung Injury Project, a population based cohort of ALI patients. The main endpoint was hospital mortality. Of 24 eligible ICUs, 13 ICUs were designated closed and 11 open. Complete survey data were available for 23 (96%) ICUs. Highe