Sustainable reduction in sound levels on intensive care units through noise management - an implementation study

The noise levels in intensive care units usually exceed the recommended limits in (inter)national recommendations. Such noise levels can affect both the recovery of intensive care patients and the performance of staff. The aim of this study was to reduce ward-based noise levels in three intensive care units (anesthesiological, neurological, and neonatological).

The implementation of a setting-specific intervention bundle consisting of (a) ward-specific guide to noise management, (b) further noise reduction and prevention measures and (c) the use of "noise traffic lights" was evaluated in an implementation study with a pre-post design. Our primary endpoint was changes in sound level (equivalent continuous sound pressure (LAeq)) 12 weeks after the intervention, and the secondary endpoint was sound level (LAeq), peak sound pressure and maximum sound level at different time points, including changes at 24-week follow-up.

After the intervention phase, we observed a significant overall reduction in the sound level of 0.77 decibels (A-weighted) (dB (A)), 95%-CI [0.06, 1.49], p = 0.034 with post-intervention measurements of LAeq_1h 56.43 dB (A) compared to pre-intervention measurements of 57.21 dB (A). The difference was particularly large (2.21 dB (A) [p < 0.0001] in one of the three intensive care units. After adjusting our analysis for the intensity of nursing workload, the sound level reduction was smaller. Comparisons of LAeq_1h between measurement times during the daytime periods showed a post-interventional difference of 58.28 dB(A) to 58.84 dB(A) baseline during the day of 0.57 dB(A), 95%-CI [-0.07, 1.21], p = 0.08 and at night of 53.36 dB(A) post-interventionally to 54.48 dB(A) baseline a difference of 1.11 dB(A) 95%-CI [0.19, 2.04], p = 0.02. In follow-up, baseline sound levels became realigned and we noted a rise in sound level of 0.81 dB (A) [p = 0.01].

Our implementation study indicates that a bundle of interventions can reduce noise levels in intensive care units, although the clinical relevance of the measured effect must be questioned. Sufficient resources and a participatory approach using an implementation framework should therefore be employed to manage sustainable noise abatement.

German Clinical Trials Register (DRKS): trial registration number: DRKS00025835; Date of registration: 12.08.2021.