Abstract
BACKGROUND: Noise exposure can negatively affect patients and staff. Patients may experience sleep disturbance, delirium and sympathetic stimulation. Communication may be hampered, and staff may experience alarm fatigue. The World Health Organization (WHO) recommends time-averaged sound levels of 35 dB. Prolonged exposure to noise levels ≥85 dB may damage hearing. Studies on noise levels in adult intensive care units (ICUs) in South Africa are lacking. OBJECTIVES: To compare noise levels with WHO recommendations, across ICUs and between recording zones. METHODS: A prospective cross-sectional research design was used. A class 2 sound-level meter measured noise levels in six adult ICUs at the central station and a patient cubicle for three 24-hour periods per ICU. RESULTS: Time-weighted sound levels (L(eq)) ranged between 48 and 65 dB. There was no statistically significant difference when comparing noise levels conditioned to ICU size, layout and between recording zones. Daytime noise levels at the central station were higher than night-time values (p<0.001) but diurnal variation was not appreciated in patient cubicles. All ICUs exceeded WHO recommendations >80% of the time. Noise levels >85 dB were very infrequent. CONCLUSION: Noise levels consistently exceeded WHO recommendations, ranging between 48 and 65 dB. ICU size and layout do not appear to influence noise levels. Elevated daytime noise levels at central stations may result from increased daytime staff and duties. Noise-protective equipment is unnecessary as noise levels do not exceed 85 dB for >8 hours, but noise-reduction strategies should be broadly implemented to improve critical care. CONTRIBUTION OF THE STUDY: This is the first study in South Africa to measure sound levels in adult intensive care units and provides baseline data which can be used to implement interventions aimed at reducing noise levels to improve care of critically ill adult patients.