Rationale: Prior studies supported an association between intensive care unit (ICU) organizational model or staffing patterns and outcome in critically ill patients.
Objectives: 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 patients with ALI. 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. Higher physician and nurse availability was reported in closed versus open ICUs. A total of 684 of 1,075 (63%) of patients with ALI were cared for in closed ICUs. After adjusting for potential confounders, patients with ALI cared for in closed ICUs had reduced hospital mortality (adjusted odds ratio, 0.68; 95% confidence interval, 0.53, 0.89; P = 0.004). Consultation by a pulmonologist in open ICUs was not associated with improved mortality (adjusted odds ratio, 0.94; 95% confidence interval, 0.74, 1.20; P = 0.62). These findings were robust for varying assumptions about the study population definition.
Conclusions: Patients with ALI cared for in a closed-model ICU have reduced mortality. These data support recommendations to implement structured intensive care in the United States.