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Abstract
Introduction Excessive noise levels in the hospital environment is a significant cause of patient and staff dissatisfaction. There are numerous studies on noise levels in hospitals, but noise frequencies in hospitals have been studied to a lesser extent. In this pilot study, we aim to identify the pertinent sound frequencies and decibel levels in a general medicine ward in a district general hospital in the UK.
Methods We deployed an industry standard octave-band noise meter (CEL-620B) to monitor the noise generated in the lobby, a side room and a shared bay of the ward at both day and night over a 1 week period. The meter was set up for continuous recording and the data was subsequently hand-curated to avoid bias from disrupted or tampered recordings.
Results Our results show that hospital noise levels can often exceed 100 dB(A); WHO guidelines advise an average of 35 dB in the day and of 30 dB at night.¹ The average peak noise was 119.5±6.50 dB(A). We found that there were higher intensities of noise at lower frequencies as opposed to at higher frequencies (figure 1) and a significant difference between noise intensities at different frequencies (figure 2).
The frequency level is negatively proportional to the average amount of noise (p<0.001). The poisson and negative binomial models were used to correct for the skewed data distribution
Distribution of averaged noise across noise meter. We identify a significant difference in the noise intensities across different frequencies (ANOVA, DF = 10, p < 0.001)
Discussion Noise frequencies from 2000 Hz to 5000 Hz may be subjectively perceived to be more unpleasant.² The intensity of noise is also likely detrimental to patient recovery and sleep quality. Our results suggest that hospitals require creative solutions in order to mitigate the adverse effects of noise generated to such specifications.
References
Berglund B, Lindvall T, Schwela DH. Guidelines for Community Noise. Geneva: World Health Organization; 1999. http://whqlibdoc.who.int/hq/1999/a68672.pdf
Kumar S, von Kriegstein K, Friston K, Griffiths TD. Features versus feelings: dissociable representations of the acoustic features and valence of aversive sounds. Journal of Neuroscience 2012;32(41):14184–14192.