Association of Intensive Care Unit Noise Spectrum with Delirium and Sleep Structure Disturbance in Patients with...

The study aimed to investigate the relationship between noise spectrum characteristics across different frequency bands in the intensive care unit (ICU) and the occurrence of delirium and sleep structure disturbances in patients with multiple organ dysfunction syndrome (MODS).

We enrolled 172 patients with MODS admitted to the Zhoushan Hospital ICU from January 2021 to September 2025. We conducted continuous environmental noise monitoring using a spectrum analyzer and measured equivalent continuous A-weighted sound pressure levels (LAeq) for low-, medium-, and high-frequency bands during daytime, nighttime, and over 72 h. We assessed delirium using the Confusion Assessment Method for the ICU (CAM-ICU) within 7 days, and patients were divided into a delirium group ( n  = 82) and a non-delirium group ( n  = 90). We compared clinical data and polysomnography-derived sleep parameters.

The 72-h LAeq was highest in the low-frequency band, and daytime and nighttime LAeq exceeded World Health Organization limits. Delirium incidence was 47.67%. Patients in the delirium group had higher low- and medium-frequency noise levels ( P < 0.05). Nighttime low-frequency noise showed a positive correlation of sleep latency with awakenings and a negative correlation with slow-wave sleep (SWS) and rapid eye movement (REM) sleep proportions ( P < 0.05). Multivariate logistic regression identified elevated nighttime low-frequency noise and decreased SWS and REM proportions as independent factors for delirium ( P < 0.05).

Nighttime low-frequency noise exposure in the ICU is associated with sleep structure disturbance with increased delirium risk in patients with MODS. Interventions targeting low-frequency noise sources may improve outcomes.