The impact of a noise reduction bundle on ICU staff: A stepped-wedge cluster randomized clinical trial

To determine the effectiveness of a multicomponent intervention bundle on sound levels in the ICU.

A stepped-wedge cluster randomized clinical trial was conducted in four intensive care units during a period of 14 months. A multicomponent intervention bundle aimed at reducing sound levels-consisting of education, equipment interventions, designated quiet times, and feedback-was implemented as a standard of care. The main outcome measures were: A-weighted sound levels (LAeq), alarms/day/bed, annoyance ratings (numeric rating scale 0-10), and the number of observed nurse distractions during medication preparation. Differences in outcomes between the intervention and control periods were tested. For the primary outcome, the minimal clinical importance difference of 3 LAeq was used, as this level is audible to humans.

LAeq control vs intervention, LAeq decreased from 53.7 (±5.8) to 52.9 (±5.9) dBA (p < 0.001) at the central nursing station. The median [IQR] number of alarms/day/bed decreased from 228 [IQR 176-290] during control to 194 [IQR 148-249] during intervention (p < 0.001). Nurses' annoyance rating control vs. intervention changed from median 3.0 [IQR 2.0-5.0] to median 3.0 [IQR 2.0-4.0] (p < 0.001). Distractions decreased from 73 % during control period to 61 % (p < 0.001) during the intervention.

Use of a multicomponent intervention bundle led to a statistically significant reduction in sound levels- though not to a clinically relevant degree. Importantly, there were statistically significant improvements in the number of alarms, as well as in nurses' annoyance and distractions, compared with the control period.