Abstract & Commentary

Can Wearing Earplugs at Night Improve Sleep and Decrease Risk for Confusion?

By Linda L. Chlan, RN, PhD, School of Nursing, University of Minnesota, is Associate Editor for Critical Care Alert.

Dr. Chlan reports that she receives grant/research support from the National Institutes of Health.

Synopsis: Earplug use early in the ICU stay can improve perceived night-time sleep quality and reduce the risk for confusion in patients.

Source: Van Rompaey B, et al. The effect of earplugs during the night on the onset of delirium and sleep perception: A randomized controlled trial in intensive care patients. Crit Care 2012;16:R73.

The purpose of this study conducted in the intensive care department of the Antwerp University Hospital in Antwerp, Belgium, was to determine if the application of earplugs to reduce sound (noise) in the ICU during the night could be beneficial in the prevention of delirium. Adult, non-mechanically ventilated ICU patients were enrolled from the 45-bed ICU department. Patients who were expected to stay for a minimum of 24 hours were enrolled early in their ICU stays. Patients were observed for a maximum of 5 nights; they were not receiving any sedation. Patients with known confusion, delirium, dementia, or hearing impairment were not included. Measures included patient clinical data, Richmond Agitation and Sedation Scale, Glasgow Coma Scale, and the Neelon & Champagne Confusion Scale (NEECHAM).

Patients (n = 136) were randomized to either night-time application of ear plugs (n = 69) or no ear plugs (n = 67). An innovative method of blinding ICU staff and data collectors was used by placing a canister at the patient's bedside that either contained the ear plugs or a dummy. The earplugs used in the study were 303 SNR 33 dB(A) manufactured by Howard Leigh Honeywell in San Diego. At 2200 hours, the canister was opened and the earplugs were placed in the patient's ears if they were in the canister. At 0600, the earplugs were removed. Patients and staff were instructed not to report whether earplugs were worn during the night. A blinded researcher collected data from all patients on their sleep perception and performed the delirium assessment using the NEECHAM at 0800, 1600, and 2200 hours. Self-reported sleep perception was assessed in the morning using a set of five questions developed by the researchers.

The patients in each study group were comparable on their clinical characteristics such as illness severity, age, and gender. A majority of the sample were male (66%) with a mean age of 59 years. Many of the patients stayed in the ICU for only 1 night. However, the patients in the earplug group were observed for an average of 43 hours, while the control group was observed for only 33 hours. The NEECHAM assessment divides patients into four categories: delirium, mild confusion, at risk, and normal. Although there was no difference between earplug and control groups with respect to the presence of frank delirium, mild confusion was present in 40% of the control patients vs 15% in the earplug group. More cognitively normal patients were found in the group sleeping with earplugs (P = 0.006). In a separate assessment using self-reported sleep quality, patients sleeping with earplugs showed a significantly better sleep after the first night (P = 0.042). Nearly half of the study group reported a good sleep, whereas only one-fourth of the control group reported a good sleep.

Commentary

The primary aim of this study was to determine if earplugs could lower the prevalence of delirium and improve sleep perception in critically ill patients. Sleep promoting interventions are understudied in the ICU. Further, the relationship between sleep and delirium is not well articulated. Given the heterogeneous and complex nature of the delirium syndrome, perceived sleep quality with a simple ICU noise reduction intervention may provide a protective benefit for patients at risk for the development of delirium. Despite the small number of patients in this study for more than 2 ICU nights, the results offer important preliminary findings on the benefit of a simple, low-cost intervention to reduce noise and promote sleep quality. Reducing noise during the night is only one intervention to enhance the ICU milieu to promote sleep and reduce risk for delirium. Other aspects of the environment, such as light exposure, warrant investigation. A multi-milieu enhancement study would shed some light on this complex, severely understudied area.

There was no use of polysomnography to document any physiological benefit from better sleep or whether patients experienced restorative sleep or less interruption of sleep with earplugs. Further, the NEECHAM may not be well known to clinicians, which may limit the transfer of these findings to clinical practice. The findings from this study are limited to short-stay ICU patients only, as most participants were in the study for < 48 hours. It is not known what the benefit may be of using earplugs to reduce noise and promote sleep quality in long-stay ICU patients.

Despite these study limitations, earplugs may be an inexpensive, simple intervention that improves perceived sleep quality and may offer some protective cognitive benefit.