Spies · Critical care medicine 2024 · prospective observational cohort pilot study · n=74

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

Cited 35 times in the scientific literature.

Level 3 - non-randomized controlled study

Prospective non-randomized controlled cohort study

PubMed 38112493 · doi:10.1097/CCM.0000000000006152 · record verified 2026-08-27

What was done

In a prospective observational cohort pilot study at a single university hospital, researchers evaluated the impact of a multicomponent ICU room redesign featuring stress-relief modifications and dynamic lighting versus standard rooms. They observed 74 mechanically ventilated adult ICU patients with an expected stay of at least 48 hours. Patients were assessed prospectively every 8 hours for depth of sedation, delirium, and pain using validated scores. Blood samples for serum melatonin profiles were collected every 4 hours for up to three 24-hour periods.

What was found

Delirium developed in 46% (n = 17) of patients in the modified rooms compared with 76% (n = 28) in standard rooms (p = 0.017). Patients in standard rooms had higher delirium severity compared to those in modified rooms (odds ratio = 2.292; 95% CI, 1.582-3.321; p < 0.0001). Light intensity significantly influenced the course of serum melatonin (p < 0.0001), with significant interaction effects over time between standard and modified rooms (p < 0.001).

Why it matters

This study provides proof-of-concept evidence that nonpharmacologic environmental adaptations, particularly dynamic lighting, can modulate circadian melatonin levels and reduce the incidence and severity of ICU delirium.

Limits

The study was a non-randomized observational pilot with a small sample size (n = 74) conducted in only two modified rooms at a single center. The multicomponent intervention prevents isolating the specific effect of dynamic lighting from other structural modifications, and room assignment was not randomized.

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