Sound in Time: An observational study to identify the sources of sound and their relative contribution to the sound environment of an intensive care unit

Background: There is a growing body of research that identifies sound levels in an intensive care unit to be higher than current recommendations; although the quality and reproducibility of these studies has been questioned. Noise is generated by the multiplicity of supportive equipment necessary for patient management and by the staff who provide or enable care. Patients remember noise as a prominent and sometimes distressing feature of their intensive care admission. There is currently no study that provides a robust description of the sources of noise in an intensive care unit. Therefore, the aim of this study was to identify the sources of sound and their relative contribution to the sound environment of an intensive care unit.& nbsp;Methods: Fifty hours of observational data were collected over a month, using a datasheet designed and piloted for this purpose. Data was collected at four bed spaces, providing equal representation across each bed space, hour of the day and day of the week. A priori, five categories of sound were identified, communication, clinical tasks, housekeeping tasks, alarms and miscellaneous; 55 individual sources of sound were reported under these categories. Concurrently, continuous sound pressure levels were monitored at each bed space.& nbsp;Results: 16,784 episodes of sound were identified during the 50hrs of data collection; the greatest number of episodes were reported in the communication category n = 5699 (34%), with clinical tasks n = 3282 (20%), housekeeping tasks n = 3247 (19%), alarms n = 2939 (18%) and miscellaneous n = 1617 (10%). The highest number of episodes for an individual sound source was nurse/nurse communication n = 1595 (10%), followed by bin lids n = 1004 (6%) and oxygen/nebulisers n = 945 (6%). Of the 55 sources recorded, the top 25 accounted for 86% of the episodes. The average SPL (L-Aeq50hrs) across all bed-spaces during this study was 65.1 dB (SD 3.98) with little variation between day (66.3 dB; SD 3.37) and night time (62.7 dB; SD 3.81), The four bed spaces demonstrated difference in average L-Aeq, with the nosiest being the single room (L(Aeq12hrs)69.1 dB, SD 1.98); and the quietest bed space 5 in an open bay (L(Aeq13hrs)59.8 dB, SD 2.49).& nbsp;Conclusion: Concurrent observational and quantitative data collection enabled detailed analysis of the sound environment. The results provide greater clarity than previous study, into the individual sound sources and their relative contribution to the noise environment of an intensive care unit. This information will help identify which sources of sound are most amenable to modification. There is a need for further study to understand the perception of noise in an intensive care unit, by its main users; the patients, staff and visitors. Current SPL guidance appears unachievable without a change in ambient sound levels. (c) 2021 Published by Elsevier Ltd.