Contribution of alarm noise to average sound pressure levels in the ICU: An observational cross-sectional study

Jeanette Vreman*, Lex M. van Loon, Wilma van den Biggelaar, Johannes G. van der Hoeven, Joris Lemson, Mark van den Boogaard

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Objectives: To explore sound levels, alarm frequencies and the association between alarms and sound levels.

Design: A single center observational cross-sectional study. Setting: Four intensive care units.

Main outcome measures: Contribution of alarms: red (life threatening), yellow (indicate excess of limits) and blue (technical) to sound pressure levels dB(A) at nursing stations.

Results: Mean sound pressure levels differed significantly between day (56.1 ± 5.5), evening (55.1 ± 5.7) and night periods 53.6 ± 5.6; p < 0.01. 175,996 alarms were recorded of which 149,764 (85%) were yellow, 18,080 (10%) were red and 8,152 (5%) were blue. The mean sound levels without alarms (background) is 56.8 dB(A), with only red: 56.0 dB(A), only yellow: 55.6 dB(A), only blue: 56.0 dB(A) and mixed alarms: 56.3 dB(A). Yellow alarms (b = −0.93; 95% CI: −1.26 to −0.6; p < 0.001) were weakly but significantly associated with mean sound levels and lead to a slight decrease in noise level (1 dB), Red alarms (b = −0.3; 95% CI: −1.237 to 0.63; p = 0.52). The R Square of the model with all alarms was 0.01 (standard error of estimate, 6.9; p < 0.001).

Conclusions: Sound levels were high during all day-periods. Alarms exceeding limits occurred most frequently. However, the contribution of alarms to sound levels measured at the nursing station is clinically limited.

Original languageEnglish
Article number102901
JournalIntensive and Critical Care Nursing
Publication statusPublished - Dec 2020


  • Acoustics
  • Alarms
  • Critical care
  • Noise
  • Patient safety
  • Sound
  • UT-Hybrid-D


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