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

Abstract

Introduction: 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?

Methods: A randomized clinical trial included adult intensive care patients in an intervention group of 69 patients sleeping with earplugs during the night and a control group of 67 patients sleeping without earplugs during the night. The researchers were blinded during data collection. Assignment was performed by an independent nurse researcher using a computer program. Eligible patients had an expected length of stay in the ICU of more than 24 hours, were Dutch- or English-speaking and scored a minimum Glasgow Coma Scale of 10. Delirium was assessed using the validated NEECHAM scale, sleep perception was reported by the patient in response to five questions.

Results: The use of earplugs during the night lowered the incidence of confusion in the studied intensive care patients. A vast improvement was shown by a Hazard Ratio of 0.47 (95% confidence interval (CI) 0.27 to 0.82). Also, patients sleeping with earplugs developed confusion later than the patients sleeping without earplugs. After the first night in the ICU, patients sleeping with earplugs reported a better sleep perception.

Conclusions: Earplugs may be a useful instrument in the prevention of confusion or delirium. The beneficial effects seem to be strongest within 48 hours after admission. The relation between sleep, sound and delirium, however, needs further research.

Trial registration: Current Controlled Trials ISRCTN36198138.

Figure 1

Flowchart showing selection and inclusion of patients.

Figure 2

NEECHAM categories observed for the study (earplugs) and the control group (no earplugs) using the worst score during the observation period of maximum five nights. Chi² for difference between earplugs and no earplugs: P = 0.006.

Figure 3

Life-time table analysis: time until first delirium or mild confusion (NEECHAM ≤ 24) for the study (earplugs) and the control group (no earplugs).

Figure 4

Sleep perception for the study (earplugs) and the control group (no earplugs). Chi² for difference between earplugs and no earplugs for each night.