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The Sleep in the Intensive Care Unit: Lowering Elements of Noise in the Critical Care Environment (SILENCE) research programme is funded by a feasibility study grant awarded by the NIHR Research for Patient Benefit scheme, and is sponsored by the University of Oxford. Final results are expected late 2018.

Intensive care © Chaikom/Shutterstock


Sound levels in the ICU are well above the recommended levels suggested by the World Health Organisation (WHO). Lowering these levels, even modestly, may help patients to sleep, and may result in fewer episodes of ICU-acquired delirium experienced by patients during their stay. Patients who develop delirium tend to have longer hospital stays and often have long-term health problems after they have been discharged home.

The SILENCE Programme is a series of studies designed to lower noise levels, improve sleep hygiene, and ultimately reduce the incidence of ICU-acquired delirium.

The final phase of the SILENCE Programme will be a ‘before/after’ feasibility study run at the John Radcliffe Hospital. During this phase data will be collected on quality and quantity of patient sleep, delirium, and noise levels. If successful locally, a multi-site RCT will be designed, and a grant application will be submitted for consideration to roll the project out more widely.

Prior to this phase the research team will determine the baseline level of delirium, develop sound and sleep protocols, and a noise feedback system which will be part of the intervention deployed alongside the alarm modifications in the final phase.

The first early-phase study will be designed to confirm the usability of a nurse-completed Richards-Campbell Sleep Questionnaire (RCSQ). Approximately 30 ICU patients will wear portable sleep monitors for up to two days and a 24-hr sleep profile will be extrapolated. The nurse-completed RCSQ will be compared against objective sleep data recorded by the monitor.

Following this, work will be conducted to test the reliability of delirium measures collected during routine care and a research database of historical ICU patient records will be interrogated to determine annual rates of delirium.

In parallel with unit level assessments data will be collected on patient experience. Interview transcripts and patient feedback questionnaires will be reviewed, and in-situ observations will be completed in the ICU to gather information about key sources of noise and how different noises affect patients, visitors, and staff. A patient-led exercise using the ‘experience-based co-design’ approach will identify areas of particular concern and prioritise practice change.

Feasibility of installing sound monitoring equipment in the intensive care unit will also be considered. Real-time noise monitoring available to staff will help inform the development of unit protocols, and aid behavioural intervention.

The noise tracking system will be developed using Human Factors-based approaches to ensure consideration of the related workflows of managerial and clinical teams, from which it will be possible to better understand what sound/noise information should be presented, and how.