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Published on: January 16, 2019
Reducing Night-Time Sound Levels Through Bed-Level Quiet ICU Bundle: A Randomised Counterbalanced Crossover Study in
Wei Jun Dan Ong1,2, Adrian Ujin Yap3,4, Woon Hean Keenan Chong5
1College of Health Sciences, Rush University, Chicago, Illinois, USA.
Background:
Elevated night-time noise in intensive care units (ICUs) may reduce alarm salience, increase cognitive workload and contribute to alarm desensitisation during bedside surveillance. Most evaluations of Quiet ICU interventions have used uncontrolled or quasi-experimental designs, limiting causal inference.
Aim:
To evaluate whether a structured bed-level Quiet ICU bundle reduced nocturnal acoustic burden in an adult ICU while preserving alarm visibility for clinical surveillance.
Study Design:
This prospective, randomised counterbalanced crossover study was conducted in an adult intensive care unit in Singapore. Eligible bed-episodes were assigned to one of two 4-night sequences: AABB or BBAA, where A represented usual care and B represented Quiet ICU. The Quiet ICU bundle included muting bedside ventilator and monitor alarm audio while maintaining central alarm visibility, alongside alarm-hygiene measures and quieter communication. Acoustic monitoring was performed overnight from 10:00 PM to 6:00 AM. The primary outcome was equivalent continuous sound level (LAeq); secondary outcomes were maximum sound level (Lmax) and time above 80 dBA. Repeated bed-night observations were analysed using linear mixed-effects models.
Results:
Sixty-nine monitored bed-episodes contributed 220 analysed nights. Compared with usual care, Quiet ICU reduced LAeq (adjusted mean difference -4.56 dBA, 95% CI -5.69 to -3.43; p < 0.001), Lmax (-7.77 dBA, 95% CI -9.47 to -6.06; p < 0.001) and time above 80 dBA (-2.43 min, 95% CI -3.63 to -1.23; p < 0.001). The LAeq reduction was likely noticeable in practice. Bedside alarm audio was reactivated on 2 of 113 Quiet ICU nights (1.8%). No safety incidents were identified.
Conclusions:
A structured bed-level Quiet ICU bundle reduced night-time acoustic burden while preserving central alarm visibility. Effects on alarm response, staff workload and patient outcomes remain uncertain.
Relevance To Clinical Practice:
In ICUs with reliable central monitoring and clear alarm-governance processes, a Quiet ICU bundle may offer a feasible, low-resource strategy to reduce bedside noise.
Study Registration:
OSF Registries; DOI: 10.17605/OSF.IO/AM59F.
