The Effects of Timed Light Exposure in Critically Ill Patients: A Randomized Controlled Pilot Clinical Trial

Nonpharmacological interventions to promote sleep in the adult critical patients unit: A scoping review

BACKGROUND

Sleep and circadian rhythms are markedly altered in intensive care unit (ICU) patients. Numerous factors related to the patient and the ICU environment affect the ability to initiate and maintain sleep. Therefore, nonpharmacological interventions could play an essential role in improving sleep and circadian rhythm.

OBJECTIVE

The aim of this study was to examine nonpharmacological interventions evaluated for promoting sleep in adult ICUs.

METHODS

A scoping review was conducted, including randomised controlled trials, nonrandomised controlled trials, quasi-experimental trials, and other controlled studies investigating the effects of nonpharmacological interventions promoting sleep in adult ICU patients.

RESULTS

A total of 57 articles and 14 ongoing trials were included in the review, of which 38 were randomised clinical trials. Nine nonpharmacological interventions to improve sleep in critically ill patients were evaluated: earplugs and/or eye masks, aromatherapy, bundles, music intervention, massage or acupressure, noise masking, bright light, and dynamic light. Most included trials simultaneously assessed the effect of more than one intervention on perceived sleep quality using questionnaires. The association between the interventions and improved sleep varied. In the case of multicomponent interventions, it is difficult to identify which components might have influenced sleep improvement.

CONCLUSIONS

Numerous studies have evaluated various nonpharmacological interventions to promote sleep in critically ill patients, several of which improved perceived sleep quality. However, the substantial variability of the assessed interventions and their implementation complicates drawing reliable conclusions.

REGISTRATION

The protocol for this scoping review was registered with the Open Science Framework under the identifier https://doi.org/10.17605/OSF.IO/MPEQ5.

Disruption of circadian rhythm as a potential pathogenesis of nocturia

Increasing evidence suggested the multifactorial nature of nocturia, but the true pathogenesis of this condition still remains to be elucidated. Contemporary clinical medications are mostly symptom based, aimed at either reducing nocturnal urine volume or targeting autonomic receptors within the bladder to facilitate urine storage. The day-night switch of the micturition pattern is controlled by circadian clocks located both in the central nervous system and in the peripheral organs. Arousal threshold and secretion of melatonin and vasopressin increase at night-time to achieve high-quality sleep and minimize nocturnal urine production. In response to the increased vasopressin, the kidney reduces the glomerular filtration rate and facilitates the reabsorption of water. Synchronously, in the bladder, circadian oscillation of crucial molecules occurs to reduce afferent sensory input and maintain sufficient bladder capacity during the night sleep period. Thus, nocturia might occur as a result of desynchronization in one or more of these circadian regulatory mechanisms. Disrupted rhythmicity of the central nervous system, kidney and bladder (known as the brain-kidney-bladder circadian axis) contributes to the pathogenesis of nocturia. Novel insights into the chronobiological nature of nocturia will be crucial to promote a revolutionary shift towards effective therapeutics targeting the realignment of the circadian rhythm.

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.

Unveiling the novel role of circadian rhythms in sepsis and septic shock: unexplored implications for chronotherapy

Circadian rhythms are critical to coordinating body processes to external environmental cues, such as light and feeding, to ensure efficiency and maintain optimal health. These rhythms are controlled by 'clock' transcription factors, such as Clock, Bmal1, Per1/2, Cry1/2, and Rev-erbs, which are present in almost every tissue. In modern society, disruptions to normal circadian rhythms are increasingly prevalent due to extended lighting, shift work, and long-distance travel. These disruptions misalign external cues to body processes and contribute to diseases such as obesity and non-alcoholic fatty liver disease. They also exacerbate pre-existing health issues, such as depression and inflammatory bowel disease. The normal inflammatory response to acute infection displays remarkable circadian rhythmicity in humans with increased inflammatory activity during the normal night or rest period. Severe bloodborne infections, exemplified in sepsis and the progression to septic shock, can not only disrupt the circadian rhythmicity of inflammatory processes but can be exacerbated by circadian misalignment. Examples of circadian disruptions during sepsis and septic shock include alteration or loss of hormonal rhythms controlling blood pressure and inflammation, white blood cell counts, and cytokine secretions. These changes to circadian rhythms hinder sepsis and septic shock recovery and also increase mortality. Chronotherapy and chronopharmacotherapy are promising approaches to resynchronise circadian rhythms or leverage circadian rhythms to optimise medication efficacy, respectively, and hold much potential in the treatment of sepsis and septic shock. Despite knowledge of how circadian rhythms change in these grave conditions, very little research has been undertaken on the use of these therapies in support of sepsis management. This review details the circadian disruptions associated with sepsis and septic shock, the influence they have on morbidity and mortality, and the potential clinical benefits of circadian-modulating therapies.

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.

Parental Perspectives From the Survey of Sleep Quality in the PICU Validation Study on Environmental Factors Causing Sleep Disruption in Critically Ill Children

OBJECTIVES

Sleep promotion bundles being tested in PICUs use elements adapted from adult bundles. As children may react differently than adults in ICU environments, this study investigated what parents report disrupted the sleep of their child in a PICU.

DESIGN

Secondary analysis of a multicenter validation study of the Survey of Sleep quality in the PICU.

SETTING

Four Northeastern U.S. PICUs, one hospital-based pediatric sleep laboratory.

PATIENTS

Parents sleeping at the bedside of a child in the PICU or hospital-based sleep laboratory.

INTERVENTIONS

Anonymous one-time survey eliciting parts of hospital or ICU environments that have been described as disruptive to sleep in validated adult ICU and pediatric inpatient questionnaires.

MEASUREMENTS AND MAIN RESULTS

Level of sleep disruption was scored by Likert scale, with higher scores indicating more disruption. Age, demographics, baseline sleep, and PICU exposures were used to describe causes of sleep disruption in a PICU. Of 152 PICU parents, 71% of their children's sleep was disrupted significantly by at least one aspect of being in the PICU. The most prevalent were "being in pain or uncomfortable because they are sick" (38%), "not sleeping at home" (30%), "alarms on machines" (28%), and "not sleeping on their home schedule" (26%). Only 5% were disrupted by excessive nocturnal light exposure. Overall sleep disruption was not different across four PICUs or in those receiving sedation. The validation study control group, healthy children undergoing polysomnography, had less sleep disruption than those in a PICU despite sleeping in a hospital-based sleep laboratory.

CONCLUSIONS

There are multiple aspects of critical care environments that affect the sleep of children, which are different from that of adults, such as disruption to home schedules. Future interventional sleep promotion bundles should include sedated children and could be applicable in multicenter settings.

Light, sleep and circadian rhythm in critical illness

PURPOSE OF REVIEW

Sleep and circadian disruption (SCD) are associated with worse outcomes in the ICU population. We discuss sleep, circadian physiology, the role of light in circadian entrainment and its possible role in treating SCD, with special attention to the use of light therapies and ICU design.

RECENT FINDINGS

The American Thoracic Society recently published an official research statement highlighting key areas required to define and treat ICU SCD. Recent literature has been predominantly observational, describing how both critical illness and the ICU environment might impair normal sleep and impact circadian rhythm. Emerging consensus guidance outlines the need for standardized light metrics in clinical trials investigating effects of light therapies. A recent proof-of-concept randomized controlled trial (RCT) showed improvement in delirium incidence and circadian alignment from ICU room redesign that included a dynamic lighting system (DLS).

SUMMARY

Further investigation is needed to define the optimal physical properties of light therapy in the ICU environment as well as timing and duration of light treatments. Work in this area will inform future circadian-promoting design, as well as multicomponent nonpharmacological protocols, to mitigate ICU SCD with the objective of improving patient outcomes.

Disruption of the circadian rhythm of melatonin: A biomarker of critical illness severity

Circadian dysrhythmias occur commonly in critically ill patients reflecting variable effects of underlying illness, ICU environment, and treatments. We retrospectively analyzed the relationship between clinical outcomes and 24-h urinary 6-sulfatoxymelatonin (aMT6s) excretion profiles in 37 critically ill patients with shock and/or respiratory failure. Nonlinear regression was used to fit a 24-h cosine curve to each patient's aMT6s profile, with rhythmicity determined by the zero-amplitude test. From these curves we determined acrophase, amplitude, phase, and night/day ratio. After assessing unadjusted relationships, we identified the optimal multivariate models for hospital survival and for discharge to home (vs. death or transfer to another facility). Normalized aMT6s rhythm amplitude was greater (p = 0.005) in patients discharged home than in those who were not, while both groups exhibited a phase delay. Patients with rhythmic aMT6s excretion were more likely to survive (OR 5.25) and be discharged home (OR 8.89; p < 0.05 for both) than patients with arrhythmic profiles, associations that persisted in multivariate modelling. In critically ill patients with shock and/or respiratory failure, arrhythmic and/or low amplitude 24-h aMT6s rhythms were associated with worse clinical outcomes, suggesting a role for the melatonin-based rhythm as a novel biomarker of critical illness severity.

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.

Actigraphy-based sleep and activity measurements in intensive care unit patients randomized to ramelteon or placebo for delirium prevention

Patients in the ICU often sleep poorly for various reasons, which may predispose to delirium. We previously conducted a clinical trial in which we tested the efficacy of ramelteon, a melatonin-receptor agonist used to treat insomnia, versus placebo, in preventing ICU delirium in patients who underwent elective pulmonary thromboendarterectomy (PTE) surgery. Here we examine sleep, activity, and circadian patterns, measured with actigraphy, to understand changes in these metrics with our intervention and in those with and without delirium. Participants wore wrist actigraphy devices while recovering post-operatively in the ICU. For sleep analysis, we extracted total sleep time and sleep fragmentation metrics over the 22:00 to 06:00 period nightly, and daytime nap duration from the daytime period (0:600 to 22:00) for each participant. For activity analyses, we extracted the following metrics: total daytime activity count (AC), maximum daytime AC, total nighttime AC, and maximum nighttime AC. Next, we performed a nonparametric circadian analysis on ACs over each 24-h day and extracted the following: interdaily stability (IS), intra-daily variability (IV), relative amplitude (RA), and low and high periods of activity (L5 and M10) as well as their start times. These metrics were compared between patients who received ramelteon versus placebo, and between patients who became delirious versus those who did not develop delirium. We additionally made comparisons between groups for daytime and nighttime light levels. No differences in sleep, activity, circadian metrics or light levels were found between drug groups. Delirious patients, when compared to those who were never delirious, had a lower IS (0.35 ± 0.16 vs. 0.47 ± 0.23; P = 0.006). Otherewise, no differences in IV, L5, M10, or RA were found between groups. L5 and M10 activity values increased significantly over the post-extubation for the whole cohort. No differences were found for daytime or nighttime light levels between groups. Overall, ramelteon did not impact sleep or circadian metrics in this cohort. Consistent with clinical experience, delirious patients had less inter-daily stability in their rest-activity rhythms. These data suggest that actigraphy might have value for individual assessment of sleep in the ICU, and for determining and detecting the impact of interventions directed at improving sleep and circadian activity rhythms in the ICU.Trial registration: REGISTERED at CLINICALTRIALS.GOV: NCT02691013. Registered on February 24, 2016 by principal investigator, Dr. Robert L. Owens.

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.

Circadian regulation of innate immunity in animals and humans and implications for human disease

Circadian rhythms are 24-h oscillating variations in physiology generated by the core circadian clock. There is now a wide body of evidence showing circadian regulation of the immune system. Innate immune cells contain the molecular circadian clock which drives rhythmic responses, from the magnitude of the inflammatory response to the numbers of circulating immune cells varying throughout the day. This leads to rhythmic presentation of disease clinically, for example the classic presentation of nocturnal asthma or the sudden development of pulmonary oedema from acute myocardial infarction first thing in the morning.

Clinical outcomes of light therapy in hospitalized patients - A systematic review

Light therapy and the effects on biological function have been known and investigated for decades. Light therapy is used to compensate for the lack of exposure to sunlight, which is thought to be linked to major depressive disorder with seasonal patterns. It is applied as sessions with bright light mimicking natural sunlight. Lack of bright light during daytime is not the only factor to maintain the circadian rhythm, also lack of exposure to bright light at night is important. A new modality called naturalistic light shows promise, mimicking daylight by dynamically changing intensity and wavelengths throughout the day. Evidence of clinical effects, besides bright light effects on depression, is still limited, especially in hospital populations, and present review aims to extract results of the effect of any optical light intervention on hospitalized patients. Through database search, 29 trials were included, of which 8 trials used a variation of naturalistic light. Trials were heterogeneous regarding designs, populations, interventions, methods and outcomes. In 14 out of 17 studies investigating sleep duration, quality and circadian alignment, along with decreased fatigue and improved mood in daytime, light therapy had a significant effect. Circadian rhythm and rhythmicity were affected as well. The effect on mood and cognition was inconsistent across studies. Trials showed more significant outcomes when conducted in non-intensive care units and with duration >5 days. Lux was reported in and compared across 24 studies and did not appear to be correlated to outcome, rather the distribution of wavelengths should be considered when conducting trials in the future. Of the 8 trials investigating naturalistic light, 4 trials had significant outcomes and 3 had adverse outcomes compared to one in the standard light regime. The overall effect of light therapy is beneficial, but evidence for the effect of naturalistic light is still insufficient to be recommended before other modalities. Future research in this area should be conducted in facilities where naturalistic light is installed, with a focus on the spectral distribution.

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.

A narrative review of interventions for improving sleep and reducing circadian disruption in medical inpatients

Sleep and circadian disruptions are frequently observed in patients across hospital wards. This is alarming, since impaired nocturnal sleep and disruption of a normal circadian rhythm can compromise health and disturb processes involved in recovery from illness (eg, immune functions). With this in mind, the present narrative review discusses how patient characteristics (sleep disorders, anxiety, stress, chronotype, and disease), hospital routines (pain management, timing of medication, nocturnal vital sign monitoring, and physical inactivity), and hospital environment (light and noise) may all contribute to sleep disturbances and circadian misalignment in patients. We also propose hospital-based strategies that may help reduce sleep and circadian disruptions in patients admitted to the hospital.