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

Impact of new lighting technology versus traditional fluorescent bulbs on sedation and delirium in the ICU

BACKGROUND

Critically ill patients frequently encounter disruptions in their circadian rhythms in the intensive care unit (ICU) environment. New lighting systems have been developed to enhance daytime light levels and to promote circadian alignment.

OBJECTIVES

To investigate the impact of implementing an innovative lighting technology that mimics natural light and reproduce the colour of the sky.

DESIGN

Prospective, observational, non-randomized comparative trial. ICU patients were exposed to either a cutting-edge lighting system based on new technology (intervention group) or a conventional lighting system using fluorescent bulbs (control group).

SETTING

An Italian intensive care unit with ten beds and five windowless rooms, thereby denying access to natural light. Three rooms had new lighting technology.

MAIN OUTCOME MEASURES

The two groups were compared to assess the prevalence or absence of delirium and the need for sedatives during ICU stay. The secondary aim was to assess the presence of anxiety, depression, and post-traumatic stress disorder in patients at 3, 6, and 12 months after ICU discharge.

RESULTS

86 patients were included: 52 (60 %) in the intervention group and 34 (40 %) in the control group. Seventy-nine patients (82 %) were alive at ICU discharge. Fourteen patients (16 %) developed delirium (intervention group: n = 8 [15 %] vs. control group: n = 6 [18 %] in the control group, (P=0.781). The use of sedative drugs and neuromuscular blocking agents was similar in both the groups. No differences in the incidence of anxiety, depression, or post-traumatic stress disorders were observed among patients who underwent follow-up visits.

CONCLUSIONS

Compared to traditional fluorescent tube lighting, the innovative lighting system did not provide any significant benefit in reducing the frequency of delirium or the necessity for sedative medications.

IMPLICATIONS FOR CLINICAL PRACTICE

A single intervention, the use of lights that mimic sunny light and the sky, did not result in a statistically significant reduction in the incidence of delirium. Delirium has a multifactorial aetiology, necessitating interventions that are multifaceted and address different domains.

Nutritional therapy for the prevention of post-intensive care syndrome

Post-intensive care syndrome (PICS) is a triad of physical, cognitive, and mental impairments that occur during or following the intensive care unit (ICU) stay, affecting the long-term prognosis of the patient and also the mental health of the patient's family. While the severity and duration of the systemic inflammation are associated with the occurrence of ICU-acquired weakness (ICU-AW), malnutrition and immobility during the treatment can exacerbate the symptoms. The goal of nutrition therapy in critically ill patients is to provide an adequate amount of energy and protein while addressing specific nutrient deficiencies to survive the inflammatory response and promote recovery from organ dysfunctions. Feeding strategy to prevent ICU-AW and PICS as nutrition therapy involves administering sufficient amounts of amino acids or proteins later in the acute phase after the hyperacute phase has passed, with specific attention to avoid energy overfeeding. Physiotherapy can also help mitigate muscle loss and subsequent physical impairment. However, many questions remain to be answered regarding the potential role and methods of nutrition therapy in association with ICU-AW and PICS, and further research is warranted.

Chrononutrition in Critical Illness

Circadian rhythms in humans are biological rhythms that regulate various physiological processes within a 24-hour time frame. Critical illness can disrupt the circadian rhythm, as can environmental and clinical factors, including altered light exposure, organ replacement therapies, disrupted sleep-wake cycles, noise, continuous enteral feeding, immobility, and therapeutic interventions. Nonpharmacological interventions, controlling the ICU environment, and pharmacological treatments are among the treatment strategies for circadian disruption. Nutrition establishes biological rhythms in metabolically active peripheral tissues and organs through appropriate synchronization with endocrine signals. Therefore, adhering to a feeding schedule based on the biological clock, a concept known as "chrononutrition," appears to be vitally important for regulating peripheral clocks. Chrononutritional approaches, such as intermittent enteral feeding that includes overnight fasting and consideration of macronutrient composition in enteral solutions, could potentially restore circadian health by resetting peripheral clocks. However, due to the lack of evidence, further studies on the effect of chrononutrition on clinical outcomes in critical illness are needed. The purpose of this review was to discuss the role of chrononutrition in regulating biological rhythms in critical illness, and its impact on clinical outcomes.

The effect of an improved ICU physical environment on outcomes and post-ICU recovery-a protocol

BACKGROUND

Intensive care medicine continues to improve, with advances in technology and care provision leading to improved patient survival. However, this has not been matched by similar advances in ICU bedspace design. Environmental factors including excessive noise, suboptimal lighting, and lack of natural lights and views can adversely impact staff wellbeing and short- and long-term patient outcomes. The personal, social, and economic costs associated with this are potentially large. The ICU of the Future project was conceived to address these issues. This is a mixed-method project, aiming to improve the ICU bedspace environment and assess impact on patient outcomes. Two innovative and adaptive ICU bedspaces capable of being individualised to patients' personal and changing needs were co-designed and implemented. The aim of this study is to evaluate the effect of an improved ICU bedspace environment on patient outcomes and operational impact.

METHODS

This is a prospective multi-component, mixed methods study including a randomised controlled trial. Over a 2-year study period, the two upgraded bedspaces will serve as intervention beds, while the remaining 25 bedspaces in the study ICU function as control beds. Study components encompass (1) an objective environmental assessment; (2) a qualitative investigation of the ICU environment and its impact from the perspective of patients, families, and staff; (3) sleep investigations; (4) circadian rhythm investigations; (5) delirium measurements; (6) assessment of medium-term patient outcomes; and (7) a health economic evaluation.

DISCUSSION

Despite growing evidence of the negative impact the ICU environment can have on patient recovery, this is an area of critical care medicine that is understudied and commonly not considered when ICUs are being designed. This study will provide new information on how an improved ICU environment impact holistic patient recovery and outcomes, potentially influencing ICU design worldwide.

TRIAL REGISTRATION

ACTRN12623000541606. Registered on May 22, 2023. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=385845&isReview=true .

Sleep quantity and quality of critically ill children perceived by caregivers and bedside nursing staff: a pilot study

STUDY OBJECTIVES

Sleep is crucial for healing but often impaired in the pediatric intensive care unit due to environmental disruptions. Caregivers and bedside nursing staff are often most aware of these factors and the impact on patient sleep, but studies have not yet compared their perceptions.

METHODS

Caregivers and bedside nursing staff of pediatric patients staying a second night in the pediatric intensive care unit were asked to complete a survey regarding environmental factors (ie, temperature, light, sound, nursing staff room entries), sleep quality, and sleep quantity (ie, sleep duration, number of naps) of the pediatric patient. Caregivers were asked similar questions about their child's sleep at home.

RESULTS

The caregivers and nursing staff of 31 pediatric patients participated in this pilot study. There was no significant difference between caregiver and nursing staff ratings of sleep quality, sleep duration, number of naps, room temperature, sound, or light (P > .05 for all). Nursing staff did report significantly more room entries than caregivers (P = .01). Compared to sleep at home, caregivers reported sleep in the hospital to be of lower quality (P = .009) with more frequent room entries (P = .01).

CONCLUSIONS

Caregivers rate their child's sleep in the pediatric intensive care unit as lower quality than sleep at home. Caregivers and bedside nursing staff largely agree about pediatric patient sleep quality and quantity as well as environmental factors. This agreement may facilitate further research and interventions at improving sleep in the pediatric intensive care unit.

CITATION

Witte MA, Lloyd RM, McGree M, Kawai Y. Sleep quantity and quality of critically ill children perceived by caregivers and bedside nursing staff: a pilot study. J Clin Sleep Med. 2023;19(12):2027-2033.

Evaluation of the sensory environment in a large tertiary ICU

BACKGROUND

ICU survival is improving. However, many patients leave ICU with ongoing cognitive, physical, and/or psychological impairments and reduced quality of life. Many of the reasons for these ongoing problems are unmodifiable; however, some are linked with the ICU environment. Suboptimal lighting and excessive noise contribute to a loss of circadian rhythms and sleep disruptions, leading to increased mortality and morbidity. Despite long-standing awareness of these problems, meaningful ICU redesign is yet to be realised, and the 'ideal' ICU design is likely to be unique to local context and patient cohorts. To inform the co-design of an improved ICU environment, this study completed a detailed evaluation of the ICU environment, focussing on acoustics, sound, and light.

METHODS

This was an observational study of the lighting and acoustic environment using sensors and formal evaluations. Selected bedspaces, chosen to represent different types of bedspaces in the ICU, were monitored during prolonged study periods. Data were analysed descriptively using Microsoft Excel.

RESULTS

Two of the three monitored bedspaces showed a limited difference in lighting levels across the day, with average daytime light intensity not exceeding 300 Lux. In bedspaces with a window, the spectral power distribution (but not intensity) of the light was similar to natural light when all ceiling lights were off. However, when the ceiling lights were on, the spectral power distribution was similar between bedspaces with and without windows. Average sound levels in the study bedspaces were 63.75, 56.80, and 59.71 dBA, with the single room being noisier than the two open-plan bedspaces. There were multiple occasions of peak sound levels > 80 dBA recorded, with the maximum sound level recorded being > 105 dBA. We recorded one new monitor or ventilator alarm commencing every 69 s in each bedspace, with only 5% of alarms actioned. Acoustic testing showed poor sound absorption and blocking.

CONCLUSIONS

This study corroborates other studies confirming that the lighting and acoustic environments in the study ICU were suboptimal, potentially contributing to adverse patient outcomes. This manuscript discusses potential solutions to identified problems. Future studies are required to evaluate whether an optimised ICU environment positively impacts patient outcomes.

Causes, Consequences, and Treatments of Sleep and Circadian Disruption in the ICU: An Official American Thoracic Society Research Statement

Background: Sleep and circadian disruption (SCD) is common and severe in the ICU. On the basis of rigorous evidence in non-ICU populations and emerging evidence in ICU populations, SCD is likely to have a profound negative impact on patient outcomes. Thus, it is urgent that we establish research priorities to advance understanding of ICU SCD. Methods: We convened a multidisciplinary group with relevant expertise to participate in an American Thoracic Society Workshop. Workshop objectives included identifying ICU SCD subtopics of interest, key knowledge gaps, and research priorities. Members attended remote sessions from March to November 2021. Recorded presentations were prepared and viewed by members before Workshop sessions. Workshop discussion focused on key gaps and related research priorities. The priorities listed herein were selected on the basis of rank as established by a series of anonymous surveys. Results: We identified the following research priorities: establish an ICU SCD definition, further develop rigorous and feasible ICU SCD measures, test associations between ICU SCD domains and outcomes, promote the inclusion of mechanistic and patient-centered outcomes within large clinical studies, leverage implementation science strategies to maximize intervention fidelity and sustainability, and collaborate among investigators to harmonize methods and promote multisite investigation. Conclusions: ICU SCD is a complex and compelling potential target for improving ICU outcomes. Given the influence on all other research priorities, further development of rigorous, feasible ICU SCD measurement is a key next step in advancing the field.

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.

Circadian rhythm disruption in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Implications for the post-acute sequelae of COVID-19

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a common and disabling disorder primarily characterized by persistent fatigue and exercise intolerance, with associated sleep disturbances, autonomic dysfunction, and cognitive problems. The causes of ME/CFS are not well understood but may coincide with immune and inflammatory responses following viral infections. During the current SARS-CoV2 coronavirus pandemic, ME/CFS has been increasingly reported to overlap with persistent “long COVID” symptoms, also called the post-acute sequelae of COVID-19 (PASC). Given the prominence of activity and sleep problems in ME/CFS, circadian rhythm disruption has been examined as a contributing factor in ME/CFS. While these studies of circadian rhythms have been pursued for decades, evidence linking circadian rhythms to ME/CFS remains inconclusive. A major limitation of older chronobiology studies of ME/CFS was the unavailability of modern molecular methods to study circadian rhythms and incomplete understanding of circadian rhythms outside the brain in peripheral organ systems. Major methodological and conceptual advancements in chronobiology have since been made. Over the same time, biomarker research in ME/CFS has progressed. Together, these new developments may justify renewed interest in circadian rhythm research in ME/CFS. Presently, we review ME/CFS from the perspective of circadian rhythms, covering both older and newer studies that make use of modern molecular methods. We focus on transforming growth factor beta (TGFB), a cytokine that has been previously associated with ME/CFS and has an important role in circadian rhythms, especially in peripheral cells. We propose that disrupted TGFB signaling in ME/CFS may play a role in disrupting physiological rhythms in sleep, activity, and cognition, leading to the insomnia, energy disturbances, cognition problems, depression, and autonomic dysfunction associated with ME/CFS. Since SARS-like coronavirus infections cause persistent changes in TGFB and previous coronavirus outbreaks have caused ME/CFS-like syndromes, chronobiological considerations may have immediate implications for understanding ME/CFS in the context of the COVID-19 pandemic and possibly suggest new avenues for therapeutic interventions.

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Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is characterized by ​disrupted ​sleep ​and activity ​implicating ​circadian clocks.

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The incidence of ME/CFS is expected to increase as a result of the post-acute sequelae of COVID-19.

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Biomarker studies in ME/CFS patients implicate Transforming Growth Factor B (TGFB).

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TGFB has roles in synchronizing circadian rhythms in peripheral cells.

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Identification of biomarkers and new methodologies may facilitate progress in the chronobiological basis of ME/CFS.

Recommendations for analgesia and sedation in critically ill children admitted to intensive care unit

We aim to develop evidence-based recommendations for intensivists caring for children admitted to intensive care units and requiring analgesia and sedation. A panel of national paediatric intensivists expert in the field of analgesia and sedation and other specialists (a paediatrician, a neuropsychiatrist, a psychologist, a neurologist, a pharmacologist, an anaesthesiologist, two critical care nurses, a methodologist) started in 2018, a 2-year process. Three meetings and one electronic-based discussion were dedicated to the development of the recommendations (presentation of the project, selection of research questions, overview of text related to the research questions, discussion of recommendations). A telematic anonymous consultation was adopted to reach the final agreement on recommendations. A formal conflict-of-interest declaration was obtained from all the authors. Eight areas of direct interest and one additional topic were considered to identify the best available evidence and to develop the recommendations using the Evidence-to-Decision framework according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. For each recommendation, the level of evidence, the strength of the recommendation, the benefits, the harms and the risks, the benefit/harm balance, the intentional vagueness, the values judgement, the exclusions, the difference of the opinions, the knowledge gaps, and the research opportunities were reported. The panel produced 17 recommendations. Nine were evaluated as strong, 3 as moderate, and 5 as weak. Conclusion: a panel of national experts achieved consensus regarding recommendations for the best care in terms of analgesia and sedation in critically ill children.

Light Levels in ICU Patient Rooms: Dimming of Daytime Light in Occupied Rooms

One-third of patients report disruption of sleep by overnight light. Importantly, light causes both immediate sleep disturbance and influences circadian function, a fundamental process underpinning high-quality sleep. Short bursts of light at night and/or lack of bright daytime light disrupt circadian alignment, leading to sleep deficiency. To improve understanding of 24-hour light patterns, we conducted a longitudinal study of light levels in intensive care unit (ICU) rooms. Over 450 room-days, we observed high variability, dim daytime light, and active dimming of natural sunlight in occupied rooms. Such noncircadian light patterns have multifactorial influences on sleep and are a key target for sleep improvement in the ICU.

Physician and Nurse Research in Multidisciplinary Intensive Care Units

BACKGROUND

Although clinical care is multidisciplinary, intensive care unit research commonly focuses on single-discipline themes. We sought to characterize intensive care unit research conducted by physicians and nurses.

METHODS

One hundred randomly selected reports of clinical studies published in critical care medical and nursing journals were reviewed.

RESULTS

Of the 100 articles reviewed, 50 were published in medical journals and 50 were published in nursing journals. Only 1 medical study (2%) used qualitative methods, compared with 9 nursing studies (18%) (P = .02). The distribution of quantitative study designs differed between medical and nursing journals (P < .001), with medical journals having a predominance of cohort studies (29 articles [58%]). Compared with medical journal articles, nursing journal articles had significantly fewer authors (median [interquartile range], 5 [3-6] vs 8 [6-10]; P < .001) and study participants (94 [51-237] vs 375 [86-4183]; P < .001) and a significantly lower proportion of male study participants (55% [26%-65%] vs 60% [51%-65%]; P = .02). Studies published in medical journals were much more likely than those published in nursing journals to exclusively involve patients as participants (47 [94%] vs 25 [50%]; P < .001). Coauthorship between physicians and nurses was evident in 14 articles (14%), with infrequent inclusion of authors from other health care disciplines.

CONCLUSIONS

Physician research and nurse research differ in several important aspects and tend to occur within silos. Increased interprofessional collaboration is possible and worthwhile.

Metabolomics Pilot Study Identifies Desynchronization of 24-H Rhythms and Distinct Intra-patient Variability Patterns in Critical Illness: A Preliminary Report

Background: Synchronized circadian rhythms play a key role in coordinating physiologic health. Desynchronized circadian rhythms may predispose individuals to disease or be indicative of underlying disease. Intensive care unit (ICU) patients likely experience desynchronized circadian rhythms due to disruptive environmental conditions in the ICU and underlying pathophysiology. This observational pilot study was undertaken to determine if 24-h rhythms are altered in ICU patients relative to healthy controls by profiling 24-h rhythms in vital signs and plasma metabolites.

Methods: We monitored daily rhythms in 5 healthy controls and 5 ICU patients for 24 h. Heart rate and blood pressure were measured every 30 min, temperature was measured every hour, and blood was sampled for mass spectrometry-based plasma metabolomics every 4 h. Bedside sound levels were measured every minute. Twenty-four hours rhythms were evaluated in vitals and putatively identified plasma metabolites individually and in each group using the cosinor method.

Results: ICU patient rooms were significantly louder than healthy controls' rooms and average noise levels were above EPA recommendations. Healthy controls generally had significant 24-h rhythms individually and as a group. While a few ICU patients had significant 24-h rhythms in isolated variables, no significant rhythms were identified in ICU patients as a group, except in cortisol. This indicates a lack of coherence in phases and amplitudes among ICU patients. Finally, principal component analysis of metabolic profiles showed surprising patterns in plasma sample clustering. Each ICU patient's samples were clearly discernable in individual clusters, separate from a single cluster of healthy controls.

Conclusions: In this pilot study, ICU patients' 24-h rhythms show significant desynchronization compared to healthy controls. Clustering of plasma metabolic profiles suggests that metabolomics could be used to track individual patients' clinical courses longitudinally. Our results show global disordering of metabolism and the circadian system in ICU patients which should be characterized further in order to determine implications for patient care.

Doing time in an Australian ICU; the experience and environment from the perspective of patients and family members

BACKGROUND

The intensive care environment and experiences during admission can negatively impact patient and family outcomes and can complicate recovery both in hospital and after discharge. While their perspectives based on intimate experiences of the environment could help inform design improvements, patients and their families are typically not involved in design processes. Rather than designing the environment around the needs of the patients, emphasis has traditionally been placed on clinical and economic efficiencies.

OBJECTIVE

The main objective was to inform design of an optimised intensive care bedspace by developing an understanding of how patients and their families experience the intensive care environment and its impact on recovery.

METHODS

A qualitative descriptive study was conducted with data collected in interviews with 17 intensive care patients and seven family members at a large cardiothoracic specialist hospital, analysed using a framework approach.

RESULTS

Participants described the intensive care as a noisy, bright, confronting and scary environment that prevented sleep and was suboptimal for recovery. Bedspaces were described as small and cluttered, with limited access to natural light or cognitive stimulation. The limited ability to personalise the environment and maintain connections with family and the outside world was considered especially problematic.

CONCLUSIONS

Intensive care patients described features of the current environment they considered problematic and potentially hindering their recovery. The perspective of patients and their families can be utilised by researchers and developers to improve the design and function of the intensive care environment. This can potentially improve patient outcomes and help deliver more personalised and effective care to this vulnerable patient population and their families.

Circadian Disruption in Critical Illness

Circadian rhythms play a vital role in metabolic, hormonal, and immunologic function and are often disrupted in patients in the ICU. Circadian rhythms modulate the molecular machinery that responds to injury and illness which can impact recovery. Potential factors contributing to the alteration in circadian rhythmicity in intensive care unit (ICU) patients include abnormal lighting, noise, altered feeding schedules, extensive patient care interactions and medications. These alterations in circadian rhythms in ICU patients may affect outcomes and therefore, normalization of circadian rhythmicity in critically ill patients may be an important part of ICU care.

The intensive care unit environment from the perspective of medical, allied health and nursing clinicians: A qualitative study to inform design of the 'ideal' bedspace

BACKGROUND

While the impact of the intensive care environment on patients' experiences and outcomes has been extensively studied, relatively little research has examined the impact on clinicians and their provision of care in the intensive care unit (ICU). Understanding staff experience and views about the environment is needed to optimise the ICU environment, patient outcomes and staff wellbeing.

OBJECTIVE

The objective of this study was to inform design of an optimised intensive care bedspace by describing clinicians' views about the current environment, including experience, impact on performance of clinical duties, and experience and outcomes of patients and family members.

METHODS

A pragmatic, qualitative descriptive study was conducted, with data collected in focus groups and interviews with 30 intensive care clinicians at a large cardiothoracic specialist hospital and analysed using the framework approach.

RESULTS

Participants acknowledged that the busy and noisy ICU provided a suboptimal healing environment for patients, was confronting for visiting families and exposed clinicians to risk of psychological injury. The bedspace, described as small and cluttered, hindered provision of clinical care of various kinds and contributed to an increased risk of staff physical injuries. Participants noted that the bland, sterile environment, devoid of natural light and views of the outside world, negatively affected both staff and patients' mood and motivation. Aware of the potential benefits of natural light, cognitive stimulation and visually appealing environments for patients and families, clinicians were frustrated by their inability to personalise the bedspace. Some participants, while acknowledging the importance of family contact for patients, were concerned about the impact of visitors on care delivery, particularly within already crowded bedspaces, suggesting restrictions on visiting.

CONCLUSIONS

Intensive care clinicians perceive that the current intensive care environment is suboptimal for patients, their families and staff and may contribute to suboptimal patient outcomes. The intensive care bedspaces need to be redesigned to ensure they are built around the needs of the people using them. Optimisation is dependent on engaging all stakeholders in future design processes.

Pilot Observational Study to Detect Diurnal Variation and Misalignment in Heart Rate Among Critically Ill Patients

Circadian disruption is common in critically ill patients admitted to the intensive care unit (ICU). Understanding and treating circadian disruption in critical illness has significant potential to improve critical illness outcomes through improved cognitive, immune, cardiovascular, and metabolic function. Measurement of circadian alignment (i.e., circadian phase) can be resource-intensive as it requires frequent blood or urine sampling over 24 or more hours. Less cumbersome methods of assessing circadian alignment would advance investigations in this field. Thus, the objective of this study is to examine the feasibility of using continuous telemetry to assess diurnal variation in heart rate (HR) among medical ICU patients as a proxy for circadian alignment. In exploratory analyses, we tested for associations between misalignment of diurnal variation in HR and death during hospital admission. This was a prospective observational cohort study embedded within a prospective medical ICU biorepository. HR data were continuously collected (every 5 s) via telemetry systems for the duration of the medical ICU admission; the first 24 h of this data was analyzed. Patients were extensively characterized via medical record chart abstraction and patient interviews. Of the 56 patients with complete HR data, 48 (86%) had a detectable diurnal variation. Of these patients with diurnal variation, 39 (81%) were characterized as having the nadir of their HR outside of the normal range of 02:00–06:00 (“misalignment”). Interestingly, no deaths occurred in the patients with normally aligned diurnal variation; in contrast, there were seven deaths (out of 39 patients) in patients who had misaligned diurnal variation in HR. In an exploratory analysis, we found that the odds ratio of death for misaligned vs. aligned patients was increased at 4.38; however, this difference was not statistically significant (95% confidence interval 0.20–97.63). We conclude that diurnal variation in HR can be detected via continuous telemetric monitoring of critically ill patients. A majority of these patients with diurnal variation exhibited misalignment in their first 24 h of medical ICU admission. Exploratory analyses suggest possible associations between misalignment and death.

The effects of noise levels on pain, anxiety, and sleep in patients

BACKGROUND

Intensive care is a noisy environment for patients and one that affects pain, anxiety levels, and sleep quality.

AIMS AND OBJECTIVES

To determine the relationship between noise levels and pain, anxiety, and sleep levels in patients in intensive care units.

DESIGN

A descriptive and observational study design was used.

METHODS

This study was conducted between June and December 2018 in a public hospital and included 111 patients admitted to surgical critical care for at least 24 hours. Three Benetech Gm1351 manual sound level metres were used to measure noise. A Patient Information Form, a pain Visual Analog Scale (VAS), the Spielberger State-Trait Anxiety Inventory, and the Richards Campbell Sleep Questionnaire (RCSQ) were used for data collection.

RESULTS

The mean age of the patients was 57.29 years. The mean noise level detected in the intensive care unit was 66.52 dB (dB). Patients' mean pain VAS score was 3.79 ± 1.72, the mean State Anxiety Inventory score was 39.74 ± 2.98, and the mean total RCSQ score was 25.10 ± 13.17. Our findings show that patients in the intensive care unit are exposed to high noise levels and that, while this has no effect on pain, it significantly impacts anxiety and quality of sleep.

CONCLUSIONS

Noise levels in intensive care units significantly exceed recommended thresholds, and this adversely affects patients' anxiety levels and sleep quality. It is important for suitably restful conditions to be provided for patients, to be aware of the potential for anxiety, and for these factors to be borne in mind when planning nursing interventions.

RELEVANCE TO CLINICAL PRACTICE

Further studies on the effects of noise levels on pain, anxiety, and sleep levels in patients admitted to intensive care units are needed.

Circadian-Hypoxia Link and its Potential for Treatment of Cardiovascular Disease

Throughout the evolutionary time, all organisms and species on Earth evolved with an adaptation to consistent oscillations of sunlight and darkness, now recognized as 'circadian rhythm.' Single-cellular to multisystem organisms use circadian biology to synchronize to the external environment and provide predictive adaptation to changes in cellular homeostasis. Dysregulation of circadian biology has been implicated in numerous prevalent human diseases, and subsequently targeting the circadian machinery may provide innovative preventative or treatment strategies. Discovery of 'peripheral circadian clocks' unleashed widespread investigations into the potential roles of clock biology in cellular, tissue, and organ function in healthy and diseased states. Particularly, oxygen-sensing pathways (e.g. hypoxia inducible factor, HIF1), are critical for adaptation to changes in oxygen availability in diseases such as myocardial ischemia. Recent investigations have identified a connection between the circadian rhythm protein Period 2 (PER2) and HIF1A that may elucidate an evolutionarily conserved cellular network that can be targeted to manipulate metabolic function in stressed conditions like hypoxia or ischemia. Understanding the link between circadian and hypoxia pathways may provide insights and subsequent innovative therapeutic strategies for patients with myocardial ischemia. This review addresses our current understanding of the connection between light-sensing pathways (PER2), and oxygen-sensing pathways (HIF1A), in the context of myocardial ischemia and lays the groundwork for future studies to take advantage of these two evolutionarily conserved pathways in the treatment of myocardial ischemia.

Intelligent ICU for Autonomous Patient Monitoring Using Pervasive Sensing and Deep Learning

Currently, many critical care indices are not captured automatically at a granular level, rather are repetitively assessed by overburdened nurses. In this pilot study, we examined the feasibility of using pervasive sensing technology and artificial intelligence for autonomous and granular monitoring in the Intensive Care Unit (ICU). As an exemplary prevalent condition, we characterized delirious patients and their environment. We used wearable sensors, light and sound sensors, and a camera to collect data on patients and their environment. We analyzed collected data to detect and recognize patient's face, their postures, facial action units and expressions, head pose variation, extremity movements, sound pressure levels, light intensity level, and visitation frequency. We found that facial expressions, functional status entailing extremity movement and postures, and environmental factors including the visitation frequency, light and sound pressure levels at night were significantly different between the delirious and non-delirious patients. Our results showed that granular and autonomous monitoring of critically ill patients and their environment is feasible using a noninvasive system, and we demonstrated its potential for characterizing critical care patients and environmental factors.

Mapping sources of noise in an intensive care unit

Excessive noise in hospitals adversely affects patients' sleep and recovery, causes stress and fatigue in staff and hampers communication. The World Health Organization suggests sound levels should be limited to 35 decibels. This is probably unachievable in intensive care units, but some reduction from current levels should be possible. A preliminary step would be to identify principal sources of noise. As part of a larger project investigating techniques to reduce environmental noise, we installed a microphone array system in one with four beds in an adult general intensive care unit. This continuously measured locations and sound pressure levels of noise sources. This report summarises results recorded over one year. Data were collected between 7 April 2017 and 16 April 2018 inclusive. Data for a whole day were available for 248 days. The sound location system revealed that the majority of loud sounds originated from extremely limited areas, very close to patients' ears. This proximity maximises the adverse effects of high environmental noise levels for patients. Some of this was likely to be appropriate communication between the patient, their caring staff and visitors. However, a significant proportion of loud sounds may originate from equipment alarms which are sited at the bedside. A redesign of the intensive care unit environment to move alarm sounds away from the bed-side might significantly reduce the environmental noise burden to patients.