Ambient light levels and critical care outcomes

Circadian Disruption and the Molecular Clock in Atherosclerosis and Hypertension

Circadian rhythms are crucial for maintaining vascular function and disruption of these rhythms are associated with negative health outcomes including cardiovascular disease and hypertension. Circadian rhythms are regulated by the central clock within the suprachiasmatic nucleus of the hypothalamus and peripheral clocks located in nearly every cell type in the body, including cells within the heart and vasculature. In this review, we summarize the most recent preclinical and clinical research linking circadian disruption, with a focus on molecular circadian clock mechanisms, in atherosclerosis and hypertension. Furthermore, we provide insight into potential future chronotherapeutics for hypertension and vascular disease. A better understanding of the influence of daily rhythms in behaviour, such as sleep/wake cycles, feeding, and physical activity, as well as the endogenous circadian system on cardiovascular risk will help pave the way for targeted approaches in atherosclerosis and hypertension treatment/prevention.

The Variable Impact of Clinical Risk-Adjustment Models to Evaluate Hospital Design

OBJECTIVES

To identify the impact of clinical risk adjustment models for evaluating pain medication consumption differences between private rooms and a multibed ward.

BACKGROUND

Views of nature are reported to reduce anxiety and pain for patients. This often leads to prioritizing large windows with views for patient rooms; however, it is not clear how other factors influencing pain (e.g., patient demographics) may confound evaluations of room design.

METHODS

We identified 1,284 patients at the University of Michigan undergoing thyroidectomy where patients recovered in one of the two locations: a private room with a view to nature or a multibed ward with no windows. We used pain medication data from the electronic medical record and risk adjustment models to evaluate pain medication consumption between the room types.

RESULTS

Private room patients did not use more pain medications when measured using unadjusted morphine milligram equivalents (18.3 vs. 15.3 mg, p = .06). Risk adjusting for age, gender, comorbidities, opioid history, and procedure subtype resulted in private room patients demonstrating higher consumption of morphine milliequivalents (17.5 vs. 15.5 mg, p < .01). In contrast, risk adjusting for age, gender, opioid history, and selected comorbidities estimated higher pain medication consumption for multibed ward patients relative to private rooms (16.27 vs. 15.51 mg, p < .05).

CONCLUSION

Estimated differences of pain medication consumption for patients in differently designed rooms varied depending on the risk adjustment model. These findings underscore the importance of understanding appropriate clinical measurement and risk adjustment strategies to accurately estimate the impact of design, before applying research into practice.

The impact of daylight and window views on length of stay among patients with heart disease: A retrospective study in a cardiac intensive care unit

Background

Heart disease is the leading cause of death in the United States. The length of stay (LOS) is a well-established parameter used to evaluate health outcomes among critically ill patients with heart disease in cardiac intensive care units (CICUs). While evidence suggests that the presence of daylight and window views can positively influence patients' LOS, no studies to date have differentiated the impact of daylight from window views on heart disease patients. Also, existing research studies on the impact of daylight and window views have failed to account for key clinical and demographic variables that can impact the benefit of such interventions in CICUs.

Methods

This retrospective study investigated the impact of access to daylight vs. window views on CICU patients' LOS. The study CICU is located in a hospital in the southeast United States and has rooms of the same size with different types of access to daylight and window views, including rooms with daylight and window views (with the patient bed located parallel to full-height, south-facing windows), rooms with daylight and no window views (with the patient bed located perpendicular to the windows), and windowless rooms. Data from electronic health records (EHRs) for the time-period September 2015 to September 2019 (n=2936) were analyzed to investigate the impact of room type on patients' CICU LOS. Linear regression models were developed for the outcome of interest, controlling for potential confounding variables.

Results

Ultimately, 2319 patients were finally included in the study analysis. Findings indicated that patients receiving mechanical ventilation in rooms with access to daylight and window views had shorter LOS durations (16.8 h) than those in windowless rooms. Sensitivity analysis for a subset of patients with LOS ≤3 days revealed that parallel bed placement to the windows and providing access to both daylight and window views significantly reduced their LOS compared to windowless rooms in the unit (P=0.007). Also, parallel bed placement to the window significantly reduced LOS in this patient subset for those with an experience of delirium (P=0.019), dementia (P=0.008), anxiety history (P=0.009), obesity (P=0.003), and those receiving palliative care (P=0.006) or mechanical ventilation (P=0.033).

Conclusions

Findings from this study could help architects make design decisions and determine optimal CICU room layouts. Identifying the patients who benefit most from direct access to daylight and window views may also help CICU stakeholders with patient assignments and hospital training programs.

Optimizing Sleep and Circadian Health in the NeuroICU

Purpose of Review

This article introduces fundamental concepts in circadian biology and the neuroscience of sleep, reviews recent studies characterizing circadian rhythm and sleep disruption among critically ill patients and potentially links to functional outcomes, and draws upon existing literature to propose therapeutic strategies to mitigate those harms. Particular attention is given to patients with critical neurologic conditions and the unique environment of the neuro-intensive care unit.

Recent Findings

Circadian rhythm disruption is widespread among critically ill patients and sleep time is reduced and abnormally fragmented. There is a strong association between the degree of arousal suppression observed at the bedside and the extent of circadian disruption at the system (e.g., melatonin concentration rhythms) and cellular levels (e.g., core clock gene transcription rhythms). There is a paucity of electrographically normal sleep, and rest-activity rhythms are severely disturbed. Common care interventions such as neurochecks introduce unique disruptions in neurologic patients. There are no pharmacologic interventions proven to normalize circadian rhythms or restore physiologically normal sleep. Instead, interventions are focused on reducing pharmacologic and environmental factors that perpetuate disruption.

Summary

The intensive care environment introduces numerous potent disruptors to sleep and circadian rhythms. Direct neurologic injury and neuro-monitoring practices likely compound those factors to further derange circadian and sleep functions. In the absence of direct interventions to induce normalized rhythms and sleep, current therapy depends upon normalizing external stimuli.

Sleep Spindles and K-Complexes Are Favorable Prognostic Biomarkers in Critically Ill Patients

SUMMARY

In this narrative review, we summarize recent research on the prognostic significance of biomarkers of sleep in continuous EEG and polysomnographic recordings in intensive care unit patients. Recent studies show the EEG biosignatures of non-rapid eye movement 2 sleep (sleep spindles and K-complexes) on continuous EEG in critically ill patients better predict functional outcomes and mortality than the ictal-interictal continuum patterns. Emergence of more complex and better organized sleep architecture has been shown to parallel neurocognitive recovery and correlate with functional outcomes in traumatic brain injury and strokes. Particularly interesting are studies which suggest intravenous dexmedetomidine may induce a more biomimetic non-rapid eye movement sleep state than intravenous propofol, potentially providing more restorative sleep and lessening delirium. Protocols to improve intensive care unit sleep and neurophysiological studies evaluating the effect of these on sleep and sleep architecture are here reviewed.

Adding Insult to Injury: Sleep Deficiency in Hospitalized Patients

Sleep deficiency is a common problem in the hospital setting. Contributing factors include preexisting medical conditions, illness severity, the hospital environment, and treatment-related effects. Hospitalized patients are particularly vulnerable to the negative health effects of sleep deficiency that impact multiple organ systems. Objective sleep measurement is difficult to achieve in the hospital setting, posing a barrier to linking improvements in hospital outcomes with sleep promotion protocols. Key next steps in hospital sleep promotion include improvement in sleep measurement techniques and harmonization of study protocols and outcomes to strengthen existing evidence and facilitate data interpretation across studies.

The Effect of Indoor Daylight Levels on Hospital Costs and Length of Stay of Patients Admitted to General Surgery

Background

Indoor daylight levels can directly affect the physical and psychological state of people. However, the effect of indoor daylight levels on the clinical recovery process of the patient remains controversial. This study was to evaluate the effect of indoor daylight levels on hospital costs and the average length of stay (LOS) of a large patient population in general surgery wards.

Methods

Data were collected retrospectively and analyzed of patients in the Second Affiliated Hospital of Zhejiang University, School of Medicine between January 2015 and August 2020. We measured daylight levels in the patient rooms of general surgery and assessed their association with the total hospital costs and LOS of the patients.

Results

A total of 2,998 patients were included in this study with 1,478 each assigned to two daylight level groups after matching. Overall comparison of hospital total costs and LOS among patients according to daylight levels did not show a significant difference. Subgroup analysis showed when exposed to higher intensity of indoor daylight, illiterate patients had lower total hospital costs (CNY ¥13070.0 vs. ¥15210.3, p = 0.018) and shorter LOS (7 vs. 10 days, p = 0.011) as compared to those exposed to a lower intensity.

Conclusions

Indoor daylight levels were not associated with the hospital costs and LOS of patients in the wards of general surgery, except for those who were illiterate. It might be essential to design guidelines for medical staff and healthcare facilities to enhance the indoor environmental benefits of daylight for some specific populations.

Association of natural light exposure and delirium according to the presence or absence of windows in the intensive care unit

Background

Patients in the intensive care unit (ICU) have increased risks of delirium, which is associated with worse outcomes. As pharmacologic treatments for delirium are ineffective, prevention is important. Nonpharmacologic preventive strategies include exposure to natural light and restoring circadian rhythm. We investigated the effect of exposure to natural light through windows on delirium in the ICU.

Methods

This retrospective cohort study assessed all patients admitted to the medical ICU of a university-affiliated hospital between January and June 2020 for eligibility. The ICU included 12 isolation rooms, six with and six without windows. Patients with ICU stays of >48 hours were included and were divided into groups based on their admission to a single room with (window group) or without windows (windowless group). The primary outcome was the cumulative incidence of delirium. The secondary outcomes were the numbers of delirium- and mechanical ventilation-free days, ICU and hospital length of stay, and in-ICU and 28-day mortalities.

Results

Of the 150 included patients (window group: 83 [55.3%]; windowless group: 67 [44.7%]), the cumulative incidence of delirium was significantly lower in the window group than in the windowless group (21.7% vs. 43.3%; relative risk, 1.996; 95% confidence interval [CI], 1.220–3.265). Other secondary outcomes did not differ between groups. Admission to a room with a window was independently associated with a decreased risk of delirium (adjusted odds ratio, 0.318; 95% CI, 0.125–0.805).

Conclusions

Exposure to natural light through windows was associated with a lower incidence of delirium in the ICU.

Intensive Care Unit Built Environments: A Comprehensive Literature Review (2005-2020)

BACKGROUND

The intensive care environment in hospitals has been the subject of significant empirical and qualitative research in the 2005-2020 period. Particular attention has been devoted to the role of infection control, family engagement, staff performance, and the built environment ramifications of the recent COVID-19 global pandemic. A comprehensive review of this literature is reported summarizing recent advancements in this rapidly expanding body of knowledge.

PURPOSE AND AIM

This comprehensive review conceptually structures the recent medical intensive care literature to provide conceptual clarity and identify current priorities and future evidence-based research and design priorities.

METHOD AND RESULT

Each source reviewed was classified as one of the five types-opinion pieces/essays, cross-sectional empirical investigations, nonrandomized comparative investigations, randomized studies, and policy review essays-and into nine content categories: nature engagement and outdoor views; family accommodations; intensive care unit (ICU), neonatal ICU, and pediatric ICU spatial configuration and amenity; noise considerations; artificial and natural lighting; patient safety and infection control; portable critical care field hospitals and disaster mitigation facilities including COVID-19; ecological sustainability; and recent planning and design trends and prognostications.

CONCLUSIONS

Among the findings embodied in the 135 literature sources reviewed, single-bed ICU rooms have increasingly become the norm; family engagement in the ICU experience has increased; acknowledgment of the therapeutic role of staff amenities; exposure to nature, view, and natural daylight has increased; the importance of ecological sustainability; and pandemic concerns have increased significantly in the wake of the coronavirus pandemic. Discussion of the results of this comprehensive review includes topics noticeably overlooked or underinvestigated in the 2005-2020 period and priorities for future research.

The relationship between sensory stimuli and the physical environment in complex healthcare settings: A systematic literature review

OBJECTIVES

This systematic review presented the current status of literature on the outcomes resulted from sensory stimuli in critical care environments as well as the environmental interventions that can improve or impede the impact of such sensory stimuli.

METHODS

Articles found through a systematic search of PsycINFO, Web of Science, and PubMed databases, in combination with a hand search, were reviewed for eligibility by two independent coders. Reporting and quality appraisals were based on PRISMA and MMAT guidelines.

RESULTS

Out of 1118 articles found, and only 30 were eligible. Final articles were comprised of issues related to noise, lighting, and temperature. Identified sensory stimuli resulted in psychological and physiological outcomes among both patients and staff. Examples include impacts on stress, delirium, sleep disturbances, poor performance and communication. The environmental factors that influence sensory stimuli included layout, room size, artificial lighting, presence of windows and acoustical interventions.

CONCLUSION

Literature on the impact of sensory stimuli on staff is scarce compared to patients. Studies on environmental interventions are inadequate and lack structure. The physical environment can impact the patient and staff outcome resulting from noise, lighting, and temperature. When applied strategically, sensory stimuli can result in positive outcomes among patients and staff.

Updated Perspectives on the Management of Sleep Disorders in the Intensive Care Unit

Sleep disorders and circadian dysrhythmias are extremely prevalent in critically ill patients. Impaired sleep has a variety of etiologies, exhibits a wide range of negative effects and, moreover, might deteriorate the patient's prognosis. Despite a number of scientific findings and increased awareness, the importance of sleep optimization is still lower on the list of priories in the intensive care unit (ICU). The techniques of measuring and the evaluation of sleep quantity and quality are a great challenge in the ICU setting. The subjective and objective tools of sleep validation continue to suffer from deficiencies. Treatment approaches to improve the critically ill patient's sleep have focused on non-pharmacologic and pharmacologic strategies with some promising results. But pharmacological interventions alone could not provide sufficient patient benefit. Being aware and knowing of sleep problems and the beneficial effect of the necessary therapies in ICU patients requires greater acceptance. The application of available methods and the development of new methods to prevent sleep disorders in the ICU offer the potential to improve the critically ill patient's outcome.

Financial impact of an analgosedation protocol for mechanically ventilated patients in a cardiovascular intensive care unit

PURPOSE

The primary objective was to evaluate the impact of an analgosedation protocol in a cardiac intensive care unit (CICU) on daily doses and costs of analgesic, sedative, and antipsychotic medications.

METHODS

We conducted a single-center quasi-experimental study in 363 mechanically ventilated patients admitted to our CICU from March 1, 2011, to April 13, 2013. On March 1, 2012, an analgosedation protocol was implemented. Patients in the pre-implementation group were managed at the cardiologist's discretion, which consisted of a continuous sedative-hypnotic approach and opioids as needed. Patients in the implementation group were managed using this protocol.

RESULTS

The mean ± S.D. per-patient doses (mg/day) of propofol, lorazepam, and clonazepam decreased with the use of an analgosedation protocol (propofol 132,265.7 ± 12,951 versus 87,980.5 ± 10,564 [p = 0.03]; lorazepam 10.5 ± 7.3 versus 3.3 ± 4.0 [p < 0.001]; clonazepam 9.9 ± 8.3 versus 1.1 ± 0.5 [p = 0.03]). The mean daily cost of propofol and lorazepam also significantly decreased (33.5% reduction in propofol cost [p = 0.03]; 69.0% reduction in lorazepam cost [p < 0.001]). The per-patient dose and cost of fentanyl (mcg/day) declined with analgosedation protocol use (fentanyl 2,274.2 ± 2317.4 versus 1,026.7 ± 981.4 [p < 0.001]; 54.8% decrease in fentanyl cost [p < 0.001]).

CONCLUSION

The implementation of an analgosedation protocol significantly decreased both the use and cost of propofol, lorazepam, and fentanyl. Further investigation of the clinical impact and cost-effectiveness of a critical care consultation service with implementation of an analgosedation protocol is warranted in the CICU.

Impact of window views on recovery-an example of post-cesarean section women

OBJECTIVE

The objective of this study was to examine the impact of urban landscape from window views on quality of care for women who underwent Cesarean Section (C-section) in Taiwan.

DESIGN

The participants were randomly assigned into 46 different hospital rooms to see the effects of various window views and daylight exposure on women's recovery from post C-section care.

SETTING

We carried out this study in the obstetrics departments of three tertiary hospitals located in two major cities of Taiwan: Taipei City and New Taipei City.

PARTICIPANTS

A total of 296 women who underwent C-sections and used patient-controlled analgesic (PCA) for pain control after their surgery during the 10-month data collection period were recruited for this study.

INTERVENTION

The 46 different patient rooms provided diverse window views and different daylight exposure for the participants.

MAIN OUTCOME MEASURES

Recovery for the women who underwent C-sections in this study was defined as PCA usage and perceived pain measured by Brief Pain Inventory (BFI).

RESULTS

Higher satisfaction of window view significantly decreased analgesic usage (P = 0.057), reduced the scores of overall perceived pain (P = 0.046), pain severity (P = 0.004), and 'pain's interference with relations with others, enjoyment of life, and mood (REM).' (P = 0.095).

CONCLUSIONS

To maximize benefit and well-being of patients recovering from surgery, health care architects should design patient rooms to create maximum satisfaction with visual impacts and optimize window views. By doing so, it may decrease the use of pain medication and substantially reduce healthcare costs.

Structure of the Anesthesia Intensive Care Units: Recommendations of the Intensive Care Section of the Spanish Society of Anaesthesiology

BACKGROUND AND OBJECTIVE

In this article, the Intensive Care Section of the Spanish Society of Anesthesiology (SCI-SEDAR) establishes new recommendations based on the standards published by the Ministry of Health, Consumer Affairs and Social Welfare and aligned with the principle international guidelines, and develops a tool to improve quality and efficiency.

MATERIALS AND METHOD

Over a 12-month period (2018), 3 members of the SCI-SEDAR defined the methodology, developed the recommendations and selected the panel of experts. Due to the limited evidence available for many of the recommendations and the significant structural differences between existing anesthesia intensive care units, we chose a modified Delphi approach to determine the degree of consensus.

RESULTS

The panel consisted of 24 experts from 21 institutions. The group put forward 175 recommendations on 8 sections, including 129 with strong consensus and 46 with weak consensus.

CONCLUSIONS

The SCI-SEDAR has established a series of structural recommendations that should be used when renovating or creating new anesthesia intensive care units.

Sleep and Circadian Rhythm in Critical Illness

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2019. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2019 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901 .

Blue Light Enhances Bacterial Clearance and Reduces Organ Injury During Sepsis

OBJECTIVES

The physiology of nearly all mammalian organisms are entrained by light and exhibit circadian rhythm. The data derived from animal studies show that light influences immunity, and these neurophysiologic pathways are maximally entrained by the blue spectrum. Here, we hypothesize that bright blue light reduces acute kidney injury by comparison with either bright red or standard, white fluorescent light in mice subjected to sepsis. To further translational relevance, we performed a pilot clinical trial of blue light therapy in human subjects with appendicitis.

DESIGN

Laboratory animal research, pilot human feasibility trial.

SETTING

University basic science laboratory and tertiary care hospital.

SUBJECTS

Male C57BL/6J mice, adult (> 17 yr) patients with acute appendicitis.

INTERVENTIONS

Mice underwent cecal ligation and puncture and were randomly assigned to a 24-hour photoperiod of bright blue, bright red, or ambient white fluorescent light. Subjects with appendicitis were randomized to receive postoperatively standard care or standard care plus high-illuminance blue light.

MEASUREMENTS AND MAIN RESULTS

Exposure to bright blue light enhanced bacterial clearance from the peritoneum, reduced bacteremia and systemic inflammation, and attenuated the degree of acute kidney injury. The mechanism involved an elevation in cholinergic tone that augmented tissue expression of the nuclear orphan receptor REV-ERBα and occurred independent of alterations in melatonin or corticosterone concentrations. Clinically, exposure to blue light after appendectomy was feasible and reduced serum interleukin-6 and interleukin-10 concentrations.

CONCLUSIONS

Modifying the spectrum of light may offer therapeutic utility in sepsis.

ICU nurses' experiences of environmental elements and their meaning for patient care at an ICU: A qualitative content analysis

In an intensive care unit (ICU), the environment is highly technological and staff are constantly present. The aim of this study was to describe environmental elements of an ICU room that nurses consider central for their provision of care. Data were collected using photovoice – photographs and in-depth interviews – and analysed using a qualitative content analysis approach. The care environment highly affected ICU nurses, in particular some elements such as medical equipment, work stations and beds. These were considered as an aid, but due to confined space some care was abstained from, maintaining privacy and confidentiality were a challenge, which led to frustration and stress. To provide care in an environment with good lightning, reduced noise and adequate space increases the wellbeing of the nurses, which indicates that an investment in a better care environment would be worthwhile.

A literature review of comfort in the paediatric critical care patient

AIMS AND OBJECTIVES

To investigate the meaning of comfort and to contextualise it within the framework of paediatric critical care.

BACKGROUND

The concept of comfort is closely linked to care in all health contexts. However, in specific settings such as the paediatric critical care unit, it takes on particular importance.

DESIGN

A literature review was conducted.

METHODS

A literature search was performed of articles in English and Spanish in international health science databases, from 1992-March 2017, applying the quality standards established by the PRISMA methodology and the Joanna Briggs Institute.

RESULTS

A total of 1,203 publications were identified in the databases. Finally, 59 articles which met the inclusion criteria were entered in this literature review. Almost all were descriptive studies written in English and published in Europe. The concept of comfort was defined as the immediate condition of being strengthened through having the three types of needs (relief, ease and transcendence) addressed in the four contexts of experience (physical, psychospiritual, social and environmental). Only two valid and reliable tools for assessing comfort were found: the Comfort Scale and the Comfort Behavior Scale.

CONCLUSIONS

Comfort is subjective and difficult to assess. It has four facets: physical, emotional, social and environmental. High levels of noise and light are the inputs that cause the most discomfort. Comfort is a holistic, universal concept and an important component of quality nursing care.

Looking for light in the din: An examination of the circadian-disrupting properties of a medical intensive care unit

OBJECTIVE

Critically ill patients exhibit profound disturbances of circadian rhythmicity, most commonly in the form of a phase delay. We investigated the specific zeitgeber properties of a medical intensive care unit to develop a model that explained these abnormalities.

RESEARCH METHODOLOGY

Prospective, observational study conducted during 2013-2014. Twenty-four-hour ambient light (lux, 672 hours) and sound pressure levels (dBA, 504 hours) were measured in patient rooms. Patients and families were surveyed regarding their perceptions of the environment.

SETTING

University-based adult medical intensive care unit.

MAIN OUTCOME MEASURES

The timing and intensity of the ambient light-dark cycle and sound environment and the relationship of these measurements to patient/family perceptions.

RESULTS

Twenty-four-hour light-dark cycles were extremely weak and phase delayed relative to the solar cycle. Morning light averaged 12.1 (4.8, 37.2) lux, when only 24.9% ± 10.9% of available light was utilised; yet patients and families did not identify low daytime light levels as problematic. Median noise levels were invariably excessive (nighttime 47.9 [45.0, 51.3] dBA) with minimal variation, consistent with the absence of a defined rest period.

CONCLUSION

The intensive care unit functions as a near-constant routine protocol disconnected from solar time. Behavioural interventions to promote entrainment should be supported by objective measurements of light and sound.

Innovative Designs for the Smart ICU

Successfully designing a new ICU requires clarity of vision and purpose and the recognition that the patient room is the core of the ICU experience for patients, staff, and visitors. The ICU can be conceptualized into three components: the patient room, central areas, and universal support services. Each patient room should be designed for single patient use and be similarly configured and equipped. The design of the room should focus upon functionality, ease of use, healing, safety, infection control, communications, and connectivity. All aspects of the room, including its infrastructure; zones for work, care, and visiting; environment, medical devices, and approaches to privacy; logistics; and waste management, are important elements in the design process. Since most medical devices used at the ICU bedside are really sophisticated computers, the ICU needs to be capable of supporting the full scope of medical informatics. The patient rooms, the central ICU areas (central stations, corridors, supply rooms, pharmacy, laboratory, staff lounge, visitor waiting room, on-call suite, conference rooms, and offices), and the universal support services (infection prevention, finishings and flooring, staff communications, signage and wayfinding, security, and fire and safety) work best when fully interwoven. This coordination helps establish efficient and safe patient throughput and care and fosters physical and social cohesiveness within the ICU. A balanced approach to centralized and decentralized monitoring and logistics also offers great flexibility. Synchronization of the universal support services in the ICU with the hospital's existing systems maintains unity of purpose and continuity across the enterprise and avoids unnecessary duplication of efforts.

Dynamic light application therapy to reduce the incidence and duration of delirium in intensive-care patients: a randomised controlled trial

BACKGROUND

Disturbed circadian rhythm is a potentially modifiable cause of delirium among patients in intensive-care units (ICUs). Bright-light therapy in the daytime can realign circadian rhythm and reduce the incidence of delirium. We investigated whether a high-intensity dynamic light application (DLA) would reduce ICU-acquired delirium.

METHODS

This was a randomised, controlled, single-centre trial of medical and surgical patients admitted to the ICU of a teaching hospital in the Netherlands. Patients older than 18 years, expected to stay in the ICU longer than 24 h and who could be assessed for delirium were randomised to DLA or normal lighting (control), according to a computer-generated schedule. The DLA was administered through ceiling-mounted fluorescent tubes that delivered bluish-white light up to 1700 lux between 0900 h and 1600 h, except for 1130-1330 h, when the light was dimmed to 300 lux. The light could only be turned off centrally by investigators. Control light levels were 300 lux and lights could be turned on and off from inside the room. The primary endpoint was the cumulative incidence of ICU-acquired delirium. Analyses were by intention to treat and per protocol. The study was terminated prematurely after an interim analysis for futility. This study is registered with Clinicaltrials.gov, number NCT01274819.

FINDINGS

Between July 1, 2011, and Sept 9, 2013, 734 patients were enrolled, 361 in the DLA group and 373 in the control group. Delirium occurred in 137 (38%) of 361 DLA patients and 123 (33%) of 373 control patients (odds ratio 1·24, 95% CI 0·92-1·68, p=0·16). No adverse events were noted in patients or staff.

INTERPRETATION

DLA as a single intervention does not reduce the cumulative incidence of delirium. Bright-light therapy should be assessed as part of a multicomponent strategy.

FUNDING

None.

Objective and subjective assessments of lighting in a hospital setting: implications for health, safety and performance

A field study was conducted to evaluate the illumination levels, to examine the effect of lighting conditions (including lighting characteristics and disturbances) on employee satisfaction, job performance, safety and health, and to compare the employees' perception of lighting level with actual illuminance levels in a hospital setting using both questionnaire and physical illuminance measurements. The illumination levels varied across different locations within the hospital and were lower than standards for 52.2% of the workplaces surveyed. Most respondents indicated that at least one of the four lighting characteristics (i.e. light level, type of light sources, light colour and use of daylight) was inappropriate, and that at least one of the three lighting disturbances (i.e. flickering lights, glare and unwanted shadows) was a major disturbance to them. The employees' perceptions of illuminance generally reflected the actual illuminance levels. The more appropriate maintenance or installation of lighting fixtures was rated as the most appropriate for improving lighting. The findings suggest that environmental ergonomics should be given a more prominent role in hospital building and workplace design to support safer healthcare facilities (for staff and potentially for patients).

PRACTITIONER SUMMARY

Good lighting is essential to improve employee performance, health and safety. The findings suggest that quantitative physical measurements should be supplemented by qualitative subjective assessments to provide a more holistic approach where specific details about the lighting condition in each working environment are incorporated from the workers' perspective.