Abstract and Introduction
Abstract
Objective: To determine whether potential exposure to natural light via windows or to more pleasing views through windows affects outcomes or costs among critically ill patients.
Design: Retrospective cohort study.
Setting: An academic hospital in Philadelphia, PA.
Patients: Six thousand one hundred thirty-eight patients admitted to a 24-bed medical ICU and 6,631 patients admitted to a 24-bed surgical ICU from July 1, 2006, to June 30, 2010.
Interventions: Assignment to medical ICU rooms with vs. without windows and to surgical ICU rooms with natural vs. industrial views based on bed availability.
Measurements and Main Results: In primary analyses adjusting for patient characteristics, medical ICU patients admitted to rooms with (n = 4,093) versus without (n = 2,243) windows did not differ in rates of ICU (p = 0.25) or in-hospital (p = 0.94) mortality, ICU readmissions (p = 0.37), or delirium (p = 0.56). Surgical ICU patients admitted to rooms with natural (n = 3,072) versus industrial (n = 3,588) views experienced slightly shorter ICU lengths of stay and slightly lower variable costs. Instrumental variable analyses based on initial bed assignment and exposure time did not show any differences in any outcomes in either the medical ICU or surgical ICU cohorts, and none of the differences noted in primary analyses remained statistically significant when adjusting for multiple comparisons. In a prespecified subgroup analysis among patients with ICU length of stay greater than 72 hours, MICU windows were associated with reduced ICU (p = 0.02) and hospital mortality (p = 0.04); these results did not meet criteria for significance after adjustment for multiple comparisons.
Conclusions: ICU rooms with windows or natural views do not improve outcomes or reduce costs of in-hospital care for general populations of medical and surgical ICU patients. Future work is needed to determine whether targeting light from windows directly toward patients influences outcomes and to explore these effects in patients at high risk for adverse outcomes.
Introduction
Efforts to modify structural elements of critical care settings hold great potential for improving outcomes and reducing costs among patients in ICUs. Although most investigators have focused on the effects of different ICU staffing practices, the influences of ICUs' physical environments on clinical and economic outcomes are beginning to be evaluated. Some studies suggest that light level, season, room directionality, and visual environments may affect outcomes, including ventilator-free days, delirium, length of stay (LOS), and use of analgesics in specific populations. However, other studies have not identified such relationships.
Despite recent elucidation of the conceptual and biological frameworks for how direct light exposure may influence the course of critical illness, the real-world impact of possible light exposure afforded by being in an ICU room with a window has not been evaluated among a large sample of general ICU patients. Additionally, despite an early observation that postcholecystectomy patients recovering in surgical ICU (SICU) rooms with natural views (i.e., containing trees) rather than industrial views (i.e., walls) experienced improved outcomes, the potentially important psychological benefits of having a more pleasing view from one's hospital room have not been reproduced.
These gaps in knowledge are particularly important given federal architectural guidelines mandating windows in every newly constructed hospital room, longstanding recommendations by the Society of Critical Care Medicine that windows be present in all ICU rooms, recent guidelines for ICU design, and the challenges faced by urban hospitals wishing to expand their ICU beds given space constraints that preclude windowed rooms. Thus, to address the mandate of new construction containing windows, we sought to quantify how a patient's exposure to windows and the views afforded through them affect clinical and economic outcomes in cohorts of general medical ICU (MICU) and SICU patients.