Title: Sleep in the ICU: Limiting Elements of Noise in the Critical Care Environment (SILENCE): a feasibility study
Funder: Department of Health and Social Care

Abstract: Background Average noise levels in intensive care units (ICUs) are comparable to a busy restaurant, with frequent louder peaks caused by staff activity and alarms. Patients treated on ICUs suffer disturbed sleep and periods of delirium in part due to this continuous background noise. Patients who develop delirium stay longer in ICU and hospital, and have long-term health problems. Many poor quality studies have attempted to reduce noise in ICUs and measure the effect, but a definitive randomised controlled trial (RCT) has not been reported. This proposal outlines the feasibility study required before such an RCT is undertaken. Aims We aim to undertake a feasibility study in one ICU to develop and test a complex intervention package including behavioural interventions to reduce staff-generated noise, technological interventions to reduce alarm noise, and to determine the measurement properties of suitable outcome measures. Plan of investigation The study will establish if an RCT of noise reduction in ICUs with patient centred outcome measures is feasible. The study will involve stages to determine the source, location and time dependence of noise pollution using a combination of continuous noise level measurement using equipment installed in the ICU and observer studies. The perceived nuisance of differing components of the noise pollution will be determined by secondary analysis of transcripts of previously recorded ex-ICU patient interviews and new focussed interviews. Possible interventions to change behaviour and procedures on the ICU to reduce noise will be developed through interviews with staff and patients. We will investigate reducing alarm noise by developing silent, tactile devices carried by nurses to replace audible alarms. Finally we will investigate the measurement properties of measures of delirium burden and sleep disturbance. We will then undertake a &ldquo;before and after&rdquo; study, where the interventions identified and developed are tested in a single ICU for six months. We estimate approximately 140 patients will be treated on the ICU whilst the interventions are in place. Progression criteria for a full RCT in an estimated 10-20 ICUs will centre on achieving a reduction in the average noise level (LAeq) of -3dB, producing a practical system that reroutes monitor alarm signals to personal alerting devices, and determining measures of dispersion for CAM-ICU negative days (burden of delirium) and the nurse-administered Richards-Campbell Sleep Questionnaire (sleep disturbance). Benefits to patients and the NHS Possible benefits to patients will be improved sleep quality whilst in the ICU, a reduced incidence of delirium, and a reduced length of ICU and hospital stay. Benefits to the NHS are reputational (improved care), cost savings from shorter ICU treatment times and reduced drug costs for treating delirium. The reduction in noise in the ICUs will also benefit staff by reducing stress levels and creating a lower risk of error. In England, Wales and Northern Ireland about 124,000 patients are admitted annually to general ICUs and a further 64,000 patients are admitted to service-specific units. Up to 40% of these patients are affected by delirium. This represents between 50,000 and 75,000 individuals who are treated annually in ICUs who might benefit from the research.

Lay abstract: Noise levels in intensive care units (ICUs) are about as loud as traffic on a main road, or conversation in a busy restaurant. Patients do not sleep well and often become confused. Patients who become confused stay longer in hospital, and often have health problems after they go home. We want to lower noise levels in 10 ICUs to see if we can improve patients sleep and reduce confusion. Before this, we need to test our plan in one ICU to find out how best to introduce noise-reducing changes into the units. This is called a feasibility study. We will look at changing the noise levels in two ways. We know from talking to patients that they find alarms annoying. The machines that check vital signs (such as heart rate and temperature) will be modified so they do not sound alerts through loudspeakers at the bedside. Instead we will send the signal to a small device, like a phone, set to vibrate. This will be carried by the nurses on the unit. We also know that patient care and general conversation cause noise. We will interview patients and staff to find out which noises are most annoying, and we will look to see where and when these noises happen most. We will then design a staff education programme to try to reduce noise. We will also put screens on the wall showing the current noise level. We will collect information on sleep and confusion in patients treated on the ICU. For the feasibility study we want to show that we can reduce average noise levels by 3dB (about 20%), that our pager-based alarm system works and that the nurses are happy to use it. We also need to check that we can accurately and reliably measure sleep and confusion.

Research activity codes: 8.1 ORGANISATION AND DELIVERY OF SERVICES
Health categories: GENERIC HEALTH RELEVANCE