Modification in ICU Design May Affect Delirium and Circadian Melatonin: A Proof of Concept Pilot Study.

Abstract

Nonpharmacologic delirium management is recommended by current guidelines, but studies on the impact of ICU design are still limited. The study's primary purpose was to determine if a multicomponent change in room design prevents ICU delirium. Second, the influence of lighting conditions on serum melatonin was assessed. Prospective observational cohort pilot study. The new design concept was established in two two-bed ICU rooms of a university hospital. Besides modifications aimed at stress relief, it includes a new dynamic lighting system. Seventy-four adult critically ill patients on mechanical ventilation with an expected ICU length of stay of at least 48 hours, treated in modified or standard rooms. None. The clinical examination included a prospective assessment for depth of sedation, delirium, and pain every 8 hours using validated scores. Blood samples for serum melatonin profiles were collected every 4 hours for a maximum of three 24-hour periods. Seventy-four patients were included in the analysis. Seventy-six percent ( n = 28) of patients in the standard rooms developed delirium compared with 46% of patients ( n = 17) in the modified rooms ( p = 0.017). Patients in standard rooms (vs. modified rooms) had a 2.3-fold higher delirium severity (odds ratio = 2.292; 95% CI, 1.582-3.321; p < 0.0001). Light intensity, calculated using the measure of circadian effective irradiance, significantly influenced the course of serum melatonin ( p < 0.0001). Significant interactions ( p < 0.001) revealed that differences in serum melatonin between patients in standard and modified rooms were not the same over time but varied in specific periods of time. Modifications in ICU room design may influence the incidence and severity of delirium. Dedicated light therapy could potentially influence delirium outcomes by modulating circadian melatonin levels.