Hear no Evil?

The effect of earplugs during the night on the onset of delirium and sleep perception: a randomized controlled trial in intensive care patients

Van Rompaey et al. Critical Care 2012, 16:R73. (full text available)



This study hypothesised that a reduction of sound during the night using earplugs could be beneficial in the prevention of intensive care delirium. Two research questions were formulated. First, does the use of earplugs during the night reduce the onset of delirium or confusion in the ICU? Second, does the use of earplugs during the night improve the quality of sleep in the ICU?

Study design

  • Randomised controlled trial comparing the effect of earplugs during the night on the onset of delirium and sleep perception
  •  In to ICU of Antwerp University Hospital, Belgium
  •  Focus of study was the early onset of delirium



  • Data collection took place from 21 November 2008 until 1 April 2009 and from 1 November 2009 until 1 April 2010.
  • Inclusion criteria: All adults more than 18 years old; Expected length of ICU stay of more than 24 hours; Dutch or English speaking; Scored minimum GCS 10/15
  • Exclusion criteria: Known hearing impairment; Dementia; Confusion/delirium on admission; On sedation

Intervention & Control

  • 69 adult ICU patients sleeping with earplugs during the night (intervention group) compared to 67 adult ICU patients sleeping without earplugs during the night (control group)
  • Delirium was assessed using the validated NEECHAM scale
  • Sleep perception was reported by the patient in response to five questions
  • Patients were observed during a maximum of 5 nights


  • The primary outcome was to lower the prevalence of delirium in the study group compared to the control group
  • The second primary outcome in this study was sleep perception in intensive care patients using or not using ear- plugs


  • Researchers screened all intensive care patients on daily basis
  • Then independent nurse assign group 1:1 ratio, using a list generated by computer program
  • Researchers blinded during data collection


  • Use of earplugs during the night lowered the incidence of confusion in the study group
  • 60% of control group showed cognitive disturbances against only 35% in the study group
  • A vast improvement was shown by a Hazard Ratio of 0.47 (95% confidence interval 0.27 to 0.82
    • Patient sleeping with earplugs developed confusion later than patients sleeping without earplugs
    • After the first night in ICU, patients sleeping with earplugs reported a better sleeping perception


  • This RCT included a specific population in their ICU- may not be applicable to all settings
  • Findings focused on the first 24 hours
  • Many patients stayed only one night in ICU
  • Being delirious made it impossible for patient to report on sleep perception (subjective measure)


  • Earplugs maybe a useful instrument in the prevention of confusion or delirium and earplugs are cheap
  • The beneficial effects seem to be strongest within 48 hours after admission
  • Study pointed at a relation between environmental sound, sleep and delirium – needs further research


Subhadra Balakrishnan



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