Excessive noise in intensive care units

Noise levels in the intensive care unit are known to be high. World Health Organization (WHO) guidelines suggest hospital noise levels should average 35 dBA during the day and 30 dBA at night.1 Research conducted by our group in five local units recorded levels just under 60 dBA during the day (equivalent to a busy restaurant) with peaks above 100 dBA 22-28 times every hour. Although it was quieter at night, we still identified peak sounds above 85 dBA up to 16 times an hour.2 These data are consistent with those of other studies. No study in a 2012 review recorded sound levels within WHO recommendations, although some interventions achieved significant reductions in sound levels.3 Staff activities and alarms are primary sources of disturbance in intensive care units,4 but noises from other patients and infrastructure also contribute.

Staff and patients may be in a chronic state of alertness when alarms are constantly sounding. Alarms share characteristics with the human scream and tend to activate areas of the brain that recognise danger. Raised sound levels have been associated …