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 Bart Van Rompaey 1 2 Monique M Elseviers 0 Wim Van Drom 0 3 Veronique Fromont 0 Philippe G Jorens 2 3 0 University of Antwerp, Faculty of Medicine and Health Sciences, Division of Nursing Science and Midwifery; Universiteitsplein 1 , 2610 Wilrijk , Belgium 1 Artesis University College of Antwerp, Department of Health Sciences J. De Boeckstraat 10 , 2170 Merksem , Belgium 2 University of Antwerp, Faculty of Medicine and Health Sciences, Universiteitsplein 1 , 2610 Wilrijk , Belgium 3 Antwerp University Hospital, Intensive Care Department , Belgium - 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. Open Access The effect of earplugs during the night on the onset of delirium and sleep perception: a randomized controlled trial in intensive care patients 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 Introduction Delirium is a common complication in the ICU caused by a malfunction of the cognitive processes in the brain. The syndrome is characterized by a fluctuating course, shifting attention, disorganized thinking and a changed level of consciousness [1]. Incidences from 20% to more than 80% are reported in different patient groups using different assessment tools. Predisposing and precipitating risk factors related to patient characteristics, chronic pathology, * Correspondence: 1University of Antwerp, Faculty of Medicine and Health Sciences, Universiteitsplein 1, 2610 Wilrijk, Belgium Full list of author information is available at the end of the article acute illness and the environment have been studied [2,3]. A patient encountering three or more of these factors has a 60% increased risk for the development of delirium [2,4]. Ely et al. stated that a patient in the ICU even accumulates ten or more of these factors [5]. Delirium often presents early after admittance to the ICU. The early onset is probably caused by an acute change in the physical situation of the patient stressed by a sensory overload. A few days after admission a cognitive healthy patient may shift to a delirium due to underlying biomedical changes or worsening illness. In this context, delirium may be called the sixth vital sign [6,7]. Next to delirium, confusion is mentioned as a symptom in different psychiatric and cognitive disorders and is described as a state of disturbed orientation in regard to time, place or person, affecting the clarity and the coherence of ones thinking [8]. Consequently, patients classified as confused have an altered perception or thought but may score negative for delirium. The ICU is a rapidly changing ward designed to admit severely ill patients. The typical character and the health care process in this unit induce heavier care sustained by high technological equipment. This equipment and the higher intensity of care also produce augmented sound levels [9]. Sound in the ICU has been a subject of research for years. Peak noise is not the main determinant disturbing the patient in the ICU. Phones ringing and people talking are reported as more annoying [10]. Although often suggested, there is ample evidence that sound influences the patients outcome. Most studies on noise report on a possible relation with sleep or on results of architectural improvements [11-14]. The quality of sleep in the ICU, however, has been related to environmental sound [10-12,15,16]. Moreover, the impact of disturbed sleep on the onset of delirium in the ICU has been proposed. Several studies showed severe fragmentation, arousals and awakenings in the sleep of ICU patients and pointed at the absence of slow wave and REM sleep. Researchers hypothesized that this disturbance of sleep could be an important role player in the onset of the delirious syndrome [17,18]. Although the impact of sleep on the onset of delirium has often been suggested, sound influencing sleep has not been identified as a risk factor for delirium yet. We hypothesized that a reduction of sound during the night using earplugs could be beneficial in the prevention of the early onset of intensive care delirium. Two primary research questions were formulated. First, does the use of earplugs during the night reduce the onset of delirium in the ICU? Second, does the use of earplugs during the night improve the quality of sleep in the ICU? Methods This study was a randomized clinical trial in which adult intensive care patients were assigned in a 1:1 ratio to an intervention group, patients sleeping with earplugs during the night, or a control group, patients sleeping without earplugs during the night. The researchers were blinded during data collection. Assignment to the study or control group was done by an independent nurse researcher using a computer program. Since the focus of this study was the early onset of delirium, patients were to be observed during a maximum of five nights. Earlier research in the same setting showed that most delirium cases presented in the first 72 hours after admission to the ICU [3,19,20]. Patients scoring positive for delirium were censored for further observation and analysis. Participants and study settings Al (...truncated)