Long-term studies measuring acoustics in ICU environments is lacking. This information is important to understand the effects of sound on seriously ill patients and those suffering from ICU delirium.
The four aims of this study included the following: (1) explore whether it is possible to implement a full-scale intervention study in the ICU concerning sound levels and their impact on the development of ICU delirium; (2) discuss methodological challenges and solutions for the forthcoming study; (3) conduct an analysis of the presence of ICU delirium in the study group; and (4) describe the sound pattern in the intervention rooms.
This study took place in one adult ICU unit where one two-bed patient room was rebuilt and an identical two-bed patient room was not modified. A quasi-randomized design was used. Patient outcomes were not compared between the two rooms but the environments were compared. To record the sound in the rooms, microphones were hung above each bed and recordings were on 24h per day. A protocol for patient placement was requested of the nursing staff.
The study participants included 25 from the non-modified room but only six from the modified room. Staffing for the day guided patient placement into rooms more than expected and often did not align with study plans. The most relevant findings from this study are implications for future research. The authors note that studies on acoustics in the ICU require consideration of the following three areas in addition to the acoustic measurement: 1) the technology used, 2) equipment, and 3) data analysis. Future research efforts should track activities in the rooms to avoid confounding variables that impact acoustical recordings.
Several significant limitations were evident in this study. First, nurses were not included in the intervention phase. Including nurses in designing the intervention might have reduced other issues such as patient placement, confounding activities, use of the CAM-ICU tool, and recruitment issues. Additionally, the fact that identical machinery had different alarm loudness may have skewed the results.