Atypical sleep in ventilated patients: empirical electroencephalography findings and the path toward revised ICU sleep scoring criteria

Do all sedatives promote biological sleep electroencephalogram patterns? A machine learning framework to identify biological sleep promoting sedatives using electroencephalogram

BACKGROUND

Sedatives are commonly used to promote sleep in intensive care unit patients. However, it is not clear whether sedation-induced states are similar to the biological sleep. We explored if sedative-induced states resemble biological sleep using multichannel electroencephalogram (EEG) recordings.

METHODS

Multichannel EEG datasets from two different sources were used in this study: (1) sedation dataset consisting of 102 healthy volunteers receiving propofol (N = 36), sevoflurane (N = 36), or dexmedetomidine (N = 30), and (2) publicly available sleep EEG dataset (N = 994). Forty-four quantitative time, frequency and entropy features were extracted from EEG recordings and were used to train the machine learning algorithms on sleep dataset to predict sleep stages in the sedation dataset. The predicted sleep states were then compared with the Modified Observer's Assessment of Alertness/ Sedation (MOAA/S) scores.

RESULTS

The performance of the model was poor (AUC = 0.55-0.58) in differentiating sleep stages during propofol and sevoflurane sedation. In the case of dexmedetomidine, the AUC of the model increased in a sedation-dependent manner with NREM stages 2 and 3 highly correlating with deep sedation state reaching an AUC of 0.80.

CONCLUSIONS

We addressed an important clinical question to identify biological sleep promoting sedatives using EEG signals. We demonstrate that propofol and sevoflurane do not promote EEG patterns resembling natural sleep while dexmedetomidine promotes states resembling NREM stages 2 and 3 sleep, based on current sleep staging standards.

Pharmacologic Sleep Aids in the Intensive Care Unit: A Systematic Review

Background: Patients in the intensive care unit (ICU) often experience poor sleep quality. Pharmacologic sleep aids are frequently used as primary or adjunctive therapy to improve sleep, although their benefits in the ICU remain uncertain. This review aims to provide a comprehensive assessment of the objective and subjective effects of medications used for sleep in the ICU, as well as their adverse effects. Methods: PubMed, Web of Science, Scopus, Embase, and Cochrane Central Register of Controlled Trials were systematically searched from their inception until June 2023 for comparative studies assessing the effects of pharmacologic sleep aids on objective and subjective metrics of sleep. Results: Thirty-four studies with 3498 participants were included. Medications evaluated were melatonin, ramelteon, suvorexant, propofol, and dexmedetomidine. The majority of studies were randomized controlled trials. Melatonin and dexmedetomidine were the best studied agents. Objective sleep metrics included polysomnography (PSG), electroencephalography (EEG), bispectral index, and actigraphy. Subjective outcome measures included patient questionnaires and nursing observations. Evidence for melatonin as a sleep aid in the ICU was mixed but largely not supportive for improving sleep. Evidence for ramelteon, suvorexant, and propofol was too limited to offer definitive recommendations. Both objective and subjective data supported dexmedetomidine as an effective sleep aid in the ICU, with PSG/EEG in 303 ICU patients demonstrating increased sleep duration and efficiency, decreased arousal index, decreased percentage of stage N1 sleep, and increased absolute and percentage of stage N2 sleep. Mild bradycardia and hypotension were reported as side effects of dexmedetomidine, whereas the other medications were reported to be safe. Several ongoing studies have not yet been published, mostly on melatonin and dexmedetomidine. Conclusions: While definitive conclusions cannot be made for most medications, dexmedetomidine improved sleep quantity and quality in the ICU. These benefits need to be balanced with possible hemodynamic side effects.

Effect of Atypical Sleep EEG Patterns on Weaning From Prolonged Mechanical Ventilation

BACKGROUND

Approximately one-third of acute ICU patients display atypical sleep patterns that cannot be interpreted by using standard EEG criteria for sleep. Atypical sleep patterns have been associated with poor weaning outcomes in acute ICUs.

RESEARCH QUESTION

Do patients being weaned from prolonged mechanical ventilation experience atypical sleep EEG patterns, and are these patterns linked with weaning outcomes?

STUDY DESIGN AND METHODS

EEG power spectral analysis during wakefulness and overnight polysomnogram were performed on alert, nondelirious patients at a long-term acute care facility.

RESULTS

Forty-four patients had been ventilated for a median duration of 38 days at the time of the polysomnogram study. Eleven patients (25%) exhibited atypical sleep EEG. During wakefulness, relative EEG power spectral analysis revealed higher relative delta power in patients with atypical sleep than in patients with usual sleep (53% vs 41%; P < .001) and a higher slow-to-fast power ratio during wakefulness: 4.39 vs 2.17 (P < .001). Patients with atypical sleep displayed more subsyndromal delirium (36% vs 6%; P = .027) and less rapid eye movement sleep (4% vs 11% total sleep time; P < .02). Weaning failure was more common in the atypical sleep group than in the usual sleep group: 91% vs 45% (P = .013).

INTERPRETATION

This study provides the first evidence that patients in a long-term acute care facility being weaned from prolonged ventilation exhibit atypical sleep EEG patterns that are associated with weaning failure. Patients with atypical sleep EEG patterns had higher rates of subsyndromal delirium and slowing of the wakeful EEG, suggesting that these two findings represent a biological signal for brain dysfunction.

Sleep Assessment in Critically Ill Patients With Acute Hypoxemic Respiratory Failure

BACKGROUND

Sleep deprivation alters respiratory muscle performance and may precipitate respiratory failure. This study aimed to assess sleep in subjects admitted to ICU for acute hypoxemic respiratory failure and its role in the risk of intubation.

METHODS

This was a prospective observational single-center cohort study including subjects admitted to ICU for de novo acute hypoxemic respiratory failure defined as breathing frequency ≥ 25 breaths/min or clinical signs of respiratory distress and PaO2 /FIO2 < 300 mm Hg while receiving high-flow nasal oxygen. Subjects with altered consciousness, central nervous or psychiatric disorders, continuous sedation or neuroleptic medication, or were uncooperative were excluded. Sleep was assessed by complete polysomnography (PSG) the night following ICU admission. The main outcome was to assess sleep among subjects with acute hypoxemic respiratory failure and to compare sleep between subjects who eventually required intubation to those who did not.

RESULTS

Over a 24-month inclusion period, 34 subjects had complete PSG, among whom 5 (15%) required intubation in the ICU. Total sleep time was 4.2 h in median (interquartile range 2.9-6.8); deep-sleep duration was 70 min (34-127), and rapid eye movement (REM) sleep duration was 9 min (0-28). Among them, 13 subjects (38%) had no REM sleep. Total sleep time and duration of deep and REM sleep stages did not differ between subjects who required intubation and those successfully treated with high-flow nasal oxygen.

CONCLUSIONS

Whereas total sleep time remained relatively preserved in critically ill subjects with acute hypoxemic respiratory failure, REM sleep time was uncommon or completely absent in a large number of subjects. Sleep did not differ between subjects who required intubation and those who did not. However, given a trend toward an increased risk of intubation in subjects with a complete absence of REM sleep, further studies are needed to better explore the impact of REM sleep on the risk of intubation.

Sleep and critical illness: a review

Critical illness and stays in the Intensive Care Unit (ICU) have significant impact on sleep. Poor sleep is common in this setting, can persist beyond acute critical illness, and is associated with increased morbidity and mortality. In the past 5 years, intensive care clinical practice guidelines have directed more focus on sleep and circadian disruption, spurring new initiatives to study and improve sleep complications in the critically ill. The global SARS-COV-2 (COVID-19) pandemic and dramatic spikes in patients requiring ICU level care also brought augmented levels of sleep disruption, the understanding of which continues to evolve. This review aims to summarize existing literature on sleep and critical illness and briefly discuss future directions in the field.

Does improving sleep for the critically ill reduce the incidence and duration of delirium? An evidence-based review

Delirium is associated with poor patient outcome. Critical-care nurses maintain that patients with disrupted sleep appear to develop delirium. We sought to explore whether improving sleep in the critically ill patients reduced the incidence and duration of delirium. Our review of five relevant studies suggests that there is low-quality evidence that improving sleep may reduce the incidence of delirium. The bidirectional association between delirium and sleep stymies research in this area, and thus, establishing cause and effect, is difficult. Research exploring other patient-centred outcomes, such as pain intensity, suggests that enhancing sleep may improve these outcomes.

Sleep in neurointensive care patients, and patients after brain tumor surgery

BACKGROUND

Severely brain injured patients treated in the neuro intensive care unit (NICU) are usually sedated. Sedation may affect not only the ability to sleep, but also the EEG rhythms used to identify sleep.

AIM

The aims were: To study if sleep patterns could be identified in the severely brain injured and sedated patients in the NICUTo study if sleep patterns could be identified in patients the night after brain tumor surgery in the neurointermediate care unit (NIMCU)To search for risk factors for not being able to sleep after brain tumor surgery.

STUDY DESIGN

Two populations were included; one with patients affected by severe brain injury and one with patients who had undergone planned brain tumor surgery. This was a quantitative observational study using EEG. Eligible neurointensive care patients for this study had to be suffering from a neurosurgical condition (for example subarachnoid haemorrhage, acute subdural hematoma, intracerebral haemorrhage and meningitis), have affected consciousness and age over 18 years. Thirty-seven patients were included from NICU. Ninety-eight patients, with a suspected glioma (WHO grade II-IV) planned for surgery were also included.

RESULTS

Neuro intensive care patients, sedated and treated in ventilator, showed no EEG sleep patterns at all. After brain tumor surgery, sleep occurred in 74% of the patients, despite frequent wake-up tests. The patients with sleep patterns were on average 8 years younger, p = 0.03.

CONCLUSIONS

Patients with severe brain injury are at risk of having no sleep when treated at the NICU, whereas after brain tumor surgery, sleep occurs in three-fourths of the patients. Further studies and new methods are warranted to identify sleep and investigate how the loss of sleep affects these patients and how sleep disturbances can be managed.

Sleep during and following critical illness: A narrative review

Sleep is a complex process influenced by biological and environmental factors. Disturbances of sleep quantity and quality occur frequently in the critically ill and remain prevalent in survivors for at least 12 mo. Sleep disturbances are associated with adverse outcomes across multiple organ systems but are most strongly linked to delirium and cognitive impairment. This review will outline the predisposing and precipitating factors for sleep disturbance, categorised into patient, environmental and treatment-related factors. The objective and subjective methodologies used to quantify sleep during critical illness will be reviewed. While polysomnography remains the gold-standard, its use in the critical care setting still presents many barriers. Other methodologies are needed to better understand the pathophysiology, epidemiology and treatment of sleep disturbance in this population. Subjective outcome measures, including the Richards-Campbell Sleep Questionnaire, are still required for trials involving a greater number of patients and provide valuable insight into patients’ experiences of disturbed sleep. Finally, sleep optimisation strategies are reviewed, including intervention bundles, ambient noise and light reduction, quiet time, and the use of ear plugs and eye masks. While drugs to improve sleep are frequently prescribed to patients in the ICU, evidence supporting their effectiveness is lacking.

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.

Altered EEG, disrupted hippocampal long-term potentiation and neurobehavioral deficits implicate a delirium-like state in a mouse model of sepsis

Sepsis and systemic inflammation are often accompanied by severe encephalopathy, sleep disruption and delirium that strongly correlate with poor clinical outcomes including long-term cognitive deficits. The cardinal manifestations of delirium are fluctuating altered mental status and inattention, identified in critically ill patients by interactive bedside assessment. The lack of analogous assessments in mouse models or clear biomarkers is a challenge to preclinical studies of delirium. In this study, we utilized concurrent measures of telemetric EEG recordings and neurobehavioral tasks in mice to characterize inattention and persistent cognitive deficits following polymicrobial sepsis. During the 24-hour critical illness period for the mice, slow-wave EEG dominance, sleep disruption, and hypersensitivity to auditory stimuli in neurobehavioral tasks resembled clinical observations in delirious patients in which alterations in similar outcome measurements, although measured differently in mice and humans, are reported. Mice were tested for nest building ability 7 days after sepsis induction, when sickness behaviors and spontaneous activity had returned to baseline. Animals that showed persistent deficits determined by poor nest building at 7 days also exhibited molecular changes in hippocampal long-term potentiation compared to mice that returned to baseline cognitive performance. Together, these behavioral and electrophysiological biomarkers offer a robust mouse model with which to further probe molecular pathways underlying brain and behavioral changes during and after acute illness such as sepsis.

Sleep quality and quantity determined by polysomnography in mechanically ventilated critically ill patients randomized to dexmedetomidine or placebo

BACKGROUND

Abnormal sleep is commonly observed in the ICU and is associated with delirium and increased mortality. If sedation is necessary, it is often performed with gamma-aminobutyric acid agonists such as propofol or midazolam leading to an absence of restorative sleep. We aim to evaluate the effect of dexmedetomidine on sleep quality and quantity.

METHODS

Thirty consecutive patients were included. The study was conducted as a double-blinded, randomized, placebo-controlled trial with two parallel groups: 20 patients were treated with dexmedetomidine, and 10 with placebo. Two 16 h of polysomnography recordings were done for each patient on two consecutive nights. Patients were randomized to dexmedetomidine or placebo after the first recording, thus providing a control recording for all patients. Dexmedetomidine was administered during the second recording (6 p.m.-6 a.m.).

OBJECTIVE

To compare the effect of dexmedetomidine versus. placebo on sleep - quality and quantity.

PRIMARY OUTCOME

Sleep quality, total sleep time (TST), Sleep efficiency (SE), and Rapid Eye Movement (REM) sleep determined by Polysomnography (PSG).

SECONDARY OUTCOME

Delirium and daytime function determined by Confusion Assessment Method of the Intensive Care Unit and physical activity. Alertness and wakefulness were determined by RASS (Richmond Agitation and Sedation Scale).

RESULTS

SE were increased in the dexmedetomidine group by; 37.6% (29.7;45.6 95% CI) versus 3.7% (-11.4;18.8 95% CI) (p < .001) and TST were prolonged by 271 min. (210;324 95% CI) versus 27 min. (-82;135 95% CI), (p < .001). No significant difference in REM sleep, delirium physical activity, or RASS score was found except for RASS night two.

CONCLUSION

Total sleep time and sleep efficiency were significantly increased, without elimination of REM sleep, in mechanically ventilated ICU patients randomized to dexmedetomidine, when compared to a control PSG recording performed during non-sedation/standard care.

Sleep staging in the ICU with heart rate variability and breathing signals. An exploratory cross-sectional study using deep neural networks

Introduction: To measure sleep in the intensive care unit (ICU), full polysomnography is impractical, while activity monitoring and subjective assessments are severely confounded. However, sleep is an intensely networked state, and reflected in numerous signals. Here, we explore the feasibility of estimating conventional sleep indices in the ICU with heart rate variability (HRV) and respiration signals using artificial intelligence methods Methods: We used deep learning models to stage sleep with HRV (through electrocardiogram) and respiratory effort (through a wearable belt) signals in critically ill adult patients admitted to surgical and medical ICUs, and in age and sex-matched sleep laboratory patients Results: We studied 102 adult patients in the ICU across multiple days and nights, and 220 patients in a clinical sleep laboratory. We found that sleep stages predicted by HRV- and breathing-based models showed agreement in 60% of the ICU data and in 81% of the sleep laboratory data. In the ICU, deep NREM (N2 + N3) proportion of total sleep duration was reduced (ICU 39%, sleep laboratory 57%, p < 0.01), REM proportion showed heavy-tailed distribution, and the number of wake transitions per hour of sleep (median 3.6) was comparable to sleep laboratory patients with sleep-disordered breathing (median 3.9). Sleep in the ICU was also fragmented, with 38% of sleep occurring during daytime hours. Finally, patients in the ICU showed faster and less variable breathing patterns compared to sleep laboratory patients Conclusion: The cardiovascular and respiratory networks encode sleep state information, which, together with artificial intelligence methods, can be utilized to measure sleep state in the ICU.

Sleep cycle in children with severe acute bronchopneumonia during mechanical ventilation at different depths of sedation

BACKGROUND

To investigate the characteristics of sleep cycle in children with severe acute bronchopneumonia treated with invasive mechanical ventilation at different sedation depths.

METHODS

We included 35 pediatric patients with severe acute bronchopneumonia treated using mechanical ventilation in Pediatric Intensive Care Unit of Shengjing Hospital of China Medical University. They were divided into deep sedation group (n = 21; ramsay score 5-6) and light sedation group (n = 14; ramsay score3-4) based on sedation depth achieved during mechanical ventilation. Long-term video electroencephalography (EEG) monitoring was performed within the first 24 h after starting mechanical ventilation and after weaning from mechanical ventilation and discontinuing sedatives and analgesics. The results were analyzed and compared with those of normal children to analyze changes in sleep cycle characteristics at different sedation depths and mechanical ventilation stages.

RESULTS

There were 29 cases altered sleep architecture. The deep sedation group had a significantly higher incidence of sleep architecture altered, total sleep duration, and non-rapid eye movement sleep-1 (NREM-1) loss incidence than the light sedation group. Moreover, the deep sedation group had a significantly lower awakening number and rapid eye movement sleep (REM) percentage than the light sedation group. The sleep cycle returned to normal in 27 (77%) patients without NREM-1 or REM sleep loss.

CONCLUSIONS

Deep sedation during mechanical ventilation allows longer total sleep duration, fewer awakenings, and an increased deep sleep proportion, but sleep architecture is severely altered. After weaning from mechanical ventilation and sedative discontinuation, lightly sedated children exhibit better sleep recovery.

Sleep assessment in critically ill adults: A systematic review and meta-analysis

PURPOSE

To systematically review sleep evaluation, characterize sleep disruption, and explore effects of sleepdisruption on outcomes in adult ICU patients.

MATERIALS AND METHODS

We systematically searched databases from May 1969 to June 2021 (PROSPERO protocol number: CRD42020175581). Prospective and retrospective studies were included studying sleep in critically ill adults, excluding patients with sleep or psychiatric disorders. Meta-regression methods were applied when feasible.

RESULTS

132 studies (8797 patients) were included. Fifteen sleep assessment methods were identified, with only two validated. Patients had significant sleep disruption, with low sleep time, and low proportion of restorative rapid eye movement (REM). Sedation was associated with higher sleep efficiency and sleep time. Surgical versus medical patients had lower sleep quality. Patients on ventilation had a higher amount of light sleep. Meta-regression only suggested an association between total sleep time and occurrence of delirium (p < 0.001, 15 studies, 519 patients). Scarce data precluded further analyses. Sleep characterized with polysomnography (PSG) correlated well with actigraphy and Richards Campbell Sleep Questionnaire (RCSQ).

CONCLUSIONS

Sleep in critically ill patients is severely disturbed, and actigraphy and RCSQ seem reliable alternatives to PSG. Future studies should evaluate impact of sleep disruption on outcomes.

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.

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.

Sensitivity and specificity of proposed Richards‐Campbell Sleep Questionnaire cut‐off scores for good quality sleep during an ICU stay

BACKGROUND

The 5-visual analogue scale Richards-Campbell Sleep Questionnaire subjective sleep measure is widely used in intensive care. A cut-off score indicative of good quality sleep has not been established and is required to guide the categorisation of individual patient and unit wide sleep quality.

DESIGN AND METHODS

The aim was to determine the global Richards-Campbell Sleep Questionnaire cut-off score for good to very good sleep during an intensive care unit stay in non-ventilated patients. The study was a secondary (cohort) retrospective analysis of patient self-report data (n = 32) from an interventional study testing a sleep promotion bundle. The Standards for Reporting Diagnostic Accuracy studies statement were used to report the study. The study was conducted in two mixed adult 12 and 20-bed ICUs of a tertiary referral hospital in a metropolitan area. In the morning, eligible patients were administered the Richards-Campbell Sleep Questionnaire together with a 5-category item Likert scale in which patients rated their nocturnal sleep quality as 'very poor', 'poor', 'fair', 'good' and 'very good'. Receiver Operator Curve analysis was performed.

RESULTS

Thirty-seven per cent (n = 32) of the total sample of 84 adult intensive care patients were females. The median age was 61.5 (51, 72) years. Self-reported median global Richards-Campbell Sleep Questionnaire score was 54.4 (30.1, 77.1) mm. A global score of ≥63.4 mm was the optimal cut-off for self-reported 'good sleep' (sensitivity: 87%, specificity: 81% and area under the curve: 0.896).

CONCLUSIONS

Although the study requires replication in ventilated patients and other ICU settings, the cut-off score (63 mm) could be used to guide the categorisation of individual patient and unit wide sleep quality.

Intensive Care-Related Cognitive Impairment: A Biopsychosocial Overview

Advancements in critical care medicine have improved survival rates for patients experiencing critical illness in intensive care units (ICUs). While mortality has declined, more than half of ICU survivors experience functional impairments that persist beyond discharge. Of particular concern is ICU-related cognitive impairment, which can extend across the care continuum, ranging from acute and transient presentations in the ICU (eg, delirium) to long-term impairments years after discharge. ICU-related cognitive impairment has received increased attention in the literature, particularly as it relates to ICU survivors who have received and survived critical care in the context of SARS-CoV-2 pandemic and are now experiencing post-acute sequelae of SARS-CoV-2 infection. The medical complexity and heterogeneity of ICU survivors, coupled with the multifactorial etiology of ICU-related cognitive impairments, lead to challenges in how to optimize care for ICU survivors at various stages of recovery. This review aims to provide an overview of cognitive outcomes associated with critical illness by integrating recent literature focused on etiology, assessment, and interventions in the context of ICU-related cognitive impairments. The narrative review employs a biopsychosocial framework to comprehensively evaluate the multifactorial nature of ICU-related cognitive outcomes. Authors also highlight multidisciplinary teams composed of key rehabilitation providers are likely best suited for optimizing recovery trajectories of ICU survivors. This article is protected by copyright. All rights reserved.

Effects of Sedatives on Sleep Architecture Measured With Odds Ratio Product in Critically Ill Patients

Supplemental Digital Content is available in the text.

OBJECTIVES:

Evaluation of sleep quality in critically ill patients is difficult using conventional scoring criteria. The aim of this study was to examine sleep in critically ill patients with and without light sedation using the odds ratio product, a validated continuous metric of sleep depth (0 = deep sleep; 2.5 = full wakefulness) that does not rely on the features needed for conventional staging.

DESIGN:

Retrospective study.

SETTINGS:

A 16-bed medical-surgical ICU.

PATIENTS:

Twenty-three mechanically ventilated patients who had previously undergone two nocturnal sleep studies, one without and one with sedation (propofol, n = 12; dexmedetomidine, n = 11).

INTERVENTIONS:

None.

MEASUREMENTS AND MAIN RESULTS:

Sleep architecture was evaluated with odds ratio product analysis by the distribution of 30-second epochs with different odds ratio product values. Electroencephalogram spectral patterns and frequency of wake intrusions (3-s odds ratio product > 1.75) were measured at different odds ratio product levels. Thirty-seven normal sleepers were used as controls. Compared with normal sleepers, unsedated critically ill patients spent little time in stable sleep (percent odds ratio product < 1.0: 31% vs 63%; p < 0.001), whereas most of the time were either in stage wake (odds ratio product > 1.75) or in a transitional state (odds ratio product 1.0–1.75), characterized by frequent wake intrusions. Propofol and dexmedetomidine had comparable effects on sleep. Sedation resulted in significant shift in odds ratio product distribution toward normal; percent odds ratio product less than 1.0 increased by 54% (p = 0.006), and percent odds ratio product greater than 1.75 decreased by 48% (p = 0.013). In six patients (26%), sedation failed to improve sleep.

CONCLUSIONS:

In stable critically ill unsedated patients, sleep quality is poor with frequent wake intrusions and little stable sleep. Light sedation with propofol or dexmedetomidine resulted in a shift in sleep architecture toward normal in most, but not all, patients.

Stress-Induced Behavioral Quiescence and Abnormal Rest-Activity Rhythms During Critical Illness

OBJECTIVES

To characterize acute alterations of circadian and ultradian rest-activity rhythms in critically ill patients and their association with brain dysfunction, systemic multiple organ dysfunction, and melatonin rhythms.

DESIGN

Prospective study observing a cohort for 48 hours beginning within the first day of ICU admission.

SETTING

ICUs within an academic medical center.

PATIENTS

Patients presenting from the community with acute onset of either intracerebral hemorrhage or sepsis as representative neurologic and systemic critical illnesses. Healthy control patients were studied in the community, during hospital bedrest, and during sleep deprivation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Circadian and ultradian characteristics of rest-activity patterns were measured by wrist actigraphy, severity of neurologic and systemic illness by Glasgow Coma Scale and Sequential Organ Failure Assessment, and central circadian rhythm by melatonin profile. We studied 112 critically ill patients, including 53 with sepsis and 59 with intracerebral hemorrhage, along with 53 control participants. Total daily activity was markedly reduced and rest-activity rhythmicity was undetectable, neither of which was replicated by hospital bedrest in healthy controls. Circadian rest-activity rhythm fragmentation and attenuation and ultradian disorganization was associated with Glasgow Coma Scale and Sequential Organ Failure Assessment in adjusted models. Rest-activity rhythms showed no detectable phase coherence with melatonin rhythms.

CONCLUSIONS

Critically ill patients rapidly enter a state of behavioral quiescence proportionate to their illness severity with concomitant disturbance of circadian and ultradian rest-activity rhythms and loss of phase coherence with the melatonin rhythm. Quiescence characteristics in rest-activity rhythms were not different in patients with and without delirium, suggesting them to be distinct phenomena. Animal models of severe physiologic stress have shown that specific neural pathway separate from the sleep-wake regulatory pathway induce behavioral quiescence and rest-activity arrhythmia, and facilitate recovery of cellular homeostasis. Whether quiescence is a conserved protective response pathway in humans is not yet understood.

Role of sleep on respiratory failure after extubation in the ICU

Background

Sleep had never been assessed immediately after extubation in patients still in the ICU. However, sleep deprivation may alter respiratory function and may promote respiratory failure. We hypothesized that sleep alterations after extubation could be associated with an increased risk of post-extubation respiratory failure and reintubation. We conducted a prospective observational cohort study performed at the medical ICU of the university hospital of Poitiers in France. Patients at high-risk of extubation failure (> 65 years, with any underlying cardiac or lung disease, or intubated > 7 days) were included. Patients intubated less than 24 h, with central nervous or psychiatric disorders, continuous sedation, neuroleptic medication, or uncooperative were excluded. Sleep was assessed by complete polysomnography just following extubation including the night. The main objective was to compare sleep between patients who developed post-extubation respiratory failure or required reintubation and the others.

Results

Over a 3-year period, 52 patients had complete polysomnography among whom 12 (23%) developed post-extubation respiratory failure and 8 (15%) required reintubation. Among them, 10 (19%) had atypical sleep, 15 (29%) had no deep sleep, and 33 (63%) had no rapid eye movement (REM) sleep. Total sleep time was 3.2 h in median [interquartile range, 2.0–4.4] in patients who developed post-extubation respiratory failure vs. 2.0 [1.1–3.8] in those who were successfully extubated (p = 0.34). Total sleep time, and durations of deep and REM sleep stages did not differ between patients who required reintubation and the others. Reintubation rates were 21% (7/33) in patients with no REM sleep and 5% (1/19) in patients with REM sleep (difference, − 16% [95% CI − 33% to 6%]; p = 0.23).

Conclusions

Sleep assessment by polysomnography after extubation showed a dramatically low total, deep and REM sleep time. Sleep did not differ between patients who were successfully extubated and those who developed post-extubation respiratory failure or required reintubation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00863-z.

Sleep staging from electrocardiography and respiration with deep learning

STUDY OBJECTIVES

Sleep is reflected not only in the electroencephalogram but also in heart rhythms and breathing patterns. We hypothesized that it is possible to accurately stage sleep based on the electrocardiogram (ECG) and respiratory signals.

METHODS

Using a dataset including 8682 polysomnograms, we develop deep neural networks to stage sleep from ECG and respiratory signals. Five deep neural networks consisting of convolutional networks and long- and short-term memory networks are trained to stage sleep using heart and breathing, including the timing of R peaks from ECG, abdominal and chest respiratory effort, and the combinations of these signals.

RESULTS

ECG in combination with the abdominal respiratory effort achieved the best performance for staging all five sleep stages with a Cohen's kappa of 0.585 (95% confidence interval ±0.017); and 0.760 (±0.019) for discriminating awake vs. rapid eye movement vs. nonrapid eye movement sleep. Performance is better for younger ages, whereas it is robust for body mass index, apnea severity, and commonly used outpatient medications.

CONCLUSIONS

Our results validate that ECG and respiratory effort provide substantial information about sleep stages in a large heterogeneous population. This opens new possibilities in sleep research and applications where electroencephalography is not readily available or may be infeasible.

Temperature rhythms and ICU sleep: the TRIS study

BACKGROUND

Core body temperature (CBT) patterns associated with sleep have not been described in the critically ill. This study aimed to characterize night-time sleep and its relationship to CBT in ICU patients.

METHODS

A prospective study was performed in a 27-bed tertiary adult intensive care unit of 20 mechanically ventilated patients in the weaning stage of their critical illness. The study assessed sleep by polysomnography (PSG) during the evening between 21:00-7:00 hours, nursing interventions using the Therapeutic Intervention Scoring System (TISS), illness severity using SOFA and APACHE II scores and CBT 24-hour pattern.

RESULTS

Patients were awake for approximately half the study period (45.04%, IQR 13.81-77-17) with no REM (0%, IQR 0-0.04%) and median arousals of 19.5/hour (IQR 7.1-40.9). The 24-hour CBT had a rhythmic pattern in 13 (65%) patients with a highly variable phase of median peak time at 17:35 hours (IQR 12:40-19:39). No significant associations were found between CBT rhythmicity, sleep stages, sleep EEG frequency density, illness severity scores or TISS on the day of PSG. There was no relationship between time awake and CBT rhythmicity (P=0.48) or CBT peak time (P=0.82). The relationship between circadian rhythms and sleep patterns in the critically ill is complex.

CONCLUSIONS

Patients recovering in ICU commonly have CBT loss of rhythmicity or a significant phase shift with loss of normal night-time patterns of sleep architecture. Appropriate care plans to promote sleep and circadian rhythm require further investigation of contributing factors such as environment, clinical care routines, illness type and severity.

The Effect of a Quality Improvement Intervention on Sleep and Delirium in Critically Ill Patients in a Surgical ICU

BACKGROUND

Delirium is a deleterious condition affecting up to 60% of patients in the surgical ICU (SICU). Few SICU-focused delirium interventions have been implemented, including those addressing sleep-wake disruption, a modifiable delirium risk factor common in critically ill patients.

RESEARCH QUESTION

What is the effect on delirium and sleep quality of a multicomponent nonpharmacologic intervention aimed at improving sleep-wake disruption in patients in the SICU setting?

STUDY DESIGN AND METHODS

Using a staggered pre-post design, we implemented a quality improvement intervention in two SICUs (general surgery or trauma and cardiovascular) in an academic medical center. After a preintervention (baseline) period, a multicomponent unit-wide nighttime (ie, efforts to minimize unnecessary sound and light, provision of earplugs and eye masks) and daytime (ie, raising blinds, promotion of physical activity) intervention bundle was implemented. A daily checklist was used to prompt staff to complete intervention bundle elements. Delirium was evaluated twice daily using the Confusion Assessment Method for the Intensive Care Unit. Patient sleep quality ratings were evaluated daily using the Richards-Campbell Sleep Questionnaire (RCSQ).

RESULTS

Six hundred forty-six SICU admissions (332 baseline, 314 intervention) were analyzed. Median age was 61 years (interquartile range, 49-70 years); 35% of the cohort were women and 83% were White. During the intervention period, patients experienced fewer days of delirium (proportion ± SD of ICU days, 15 ± 27%) as compared with the preintervention period (20 ± 31%; P = .022), with an adjusted pre-post decrease of 4.9% (95% CI, 0.5%-9.2%; P = .03). Overall RCSQ-perceived sleep quality ratings did not change, but the RCSQ noise subscore increased (9.5% [95% CI, 1.1%-17.5%; P = .02).

INTERPRETATION

Our multicomponent intervention was associated with a significant reduction in the proportion of days patients experienced delirium, reinforcing the feasibility and effectiveness of a nonpharmacologic sleep-wake bundle to reduce delirium in critically ill patients in the SICU.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT03313115; URL: www.clinicaltrials.gov.

Sleep quality assessment in intensive care: actigraphy vs. Richards-Campbell sleep questionnaire

Introduction

It has been repeatedly shown that sleep of intensive care unit (ICU) patients is fragmented and its architecture is impaired. As sleep disorders have numerous negative effects on the organism, there have been efforts to implement sleep-promoting strategies into practice. When comparing the effectiveness of such measures, sleep quality assessment itself is a considerable problem.

Objective

The study aimed to assess the quality and quantity of night sleep in ICU patients simultaneously with actigraphy (ACT) and the Richards-Campbell Sleep Questionnaire (RCSQ). The secondary goals were to test the performance and effectiveness of the above methods and to verify correlations between selected RCSQ items and actigraph parameters.

Methods

A single-center prospective observational study (20 patients staying in a Interdisciplinary Intensive Care Unit). The quality of sleep was assessed using a Czech version of the RCSQ and ACT. The obtained data were analyzed and their dependence or correlations were verified by selected statistical tests.

Results

The mean RCSQ score was 47.6 (SD 24.4). The worst results were found for sleep latency (44.4; SD 31.2); the best results were for sleep quality (50.2; SD 29.4). The mean sleep effciency measured with ACT reached 86.6% (SD 9.2); the mean number of awakenings per night was 17.1 (SD 8.5). The RCSQ total parameter with a cutoff of 50 (RCSQ total = 50 good sleep / RCSQ total < 50 poor sleep) was shown to be suitable for discrimination of subjectively perceived sleep quality in ICU patients. However, the study failed to show statistically significant relations between subjectively perceived sleep quality (RCSQ) and ACT measurements.

Conclusion

The RCSQ appears to be a suitable instrument for assessing night sleep quality in ICU patients. On the other hand, the study showed a very low level of agreement between subjective sleep quality assessment and objective ACT measurements. The main drawback of ACT is low reliability of obtained data. Further research is needed to determine its role in sleep quality assessment in the ICU setting.

Impact of Sleep Deprivation in the Neurological Intensive Care Unit: A Narrative Review

Sleep is fundamental for everyday functioning, yet it is often negatively impacted in critically ill patients by the intensive care setting. With a focus on the neurological intensive care unit (NeuroICU), this narrative review summarizes methods of measuring sleep and addresses common causes of sleep disturbance in the hospital including environmental, pharmacological, and patient-related factors. The effects of sleep deprivation on the cardiovascular, pulmonary, immune, endocrine, and neuropsychological systems are discussed, with a focus on short-term deprivation in critically ill populations. Where evidence is lacking in the literature, long-term sleep deprivation studies and the effects of sleep deprivation in healthy individuals are also referenced. Lastly, strategies for the promotion of sleep in the NeuroICU are presented.

A Timely Call to Arms: COVID-19, the Circadian Clock, and Critical Care

We currently find ourselves in the midst of a global coronavirus disease 2019 (COVID-19) pandemic, caused by the highly infectious novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we discuss aspects of SARS-CoV-2 biology and pathology and how these might interact with the circadian clock of the host. We further focus on the severe manifestation of the illness, leading to hospitalization in an intensive care unit. The most common severe complications of COVID-19 relate to clock-regulated human physiology. We speculate on how the pandemic might be used to gain insights on the circadian clock but, more importantly, on how knowledge of the circadian clock might be used to mitigate the disease expression and the clinical course of COVID-19.

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.

Challenges of Delirium Management in Patients with Traumatic Brain Injury: From Pathophysiology to Clinical Practice

Traumatic brain injury (TBI) can initiate a very complex disease of the central nervous system (CNS), starting with the primary pathology of the inciting trauma and subsequent inflammatory and CNS tissue response. Delirium has long been regarded as an almost inevitable consequence of moderate to severe TBI, but more recently has been recognized as an organ dysfunction syndrome with potentially mitigating interventions. The diagnosis of delirium is independently associated with prolonged hospitalization, increased mortality and worse cognitive outcome across critically ill populations. Investigation of the unique problems and management challenges of TBI patients is needed to reduce the burden of delirium in this population. In this narrative review, possible etiologic mechanisms behind post-traumatic delirium are discussed, including primary injury to structures mediating arousal and attention and secondary injury due to progressive inflammatory destruction of the brain parenchyma. Other potential etiologic contributors include dysregulation of neurotransmission due to intravenous sedatives, seizures, organ failure, sleep cycle disruption or other delirium risk factors. Delirium screening can be accomplished in TBI patients and the presence of delirium portends worse outcomes. There is evidence that multi-component care bundles including an analgesia-prioritized sedation algorithm, regular spontaneous awakening and breathing trials, protocolized delirium assessment, early mobility and family engagement can reduce the burden of ICU delirium. The aim of this review is to summarize the approach to delirium in TBI patients with an emphasis on pathogenesis and management. Emerging CNS-active drug therapies that show promise in preclinical studies are highlighted.

Protocol for the Prognosticating Delirium Recovery Outcomes Using Wakefulness and Sleep Electroencephalography (P-DROWS-E) study: a prospective observational study of delirium in elderly cardiac surgical patients

INTRODUCTION

Delirium is a potentially preventable disorder characterised by acute disturbances in attention and cognition with fluctuating severity. Postoperative delirium is associated with prolonged intensive care unit and hospital stay, cognitive decline and mortality. The development of biomarkers for tracking delirium could potentially aid in the early detection, mitigation and assessment of response to interventions. Because sleep disruption has been posited as a contributor to the development of this syndrome, expression of abnormal electroencephalography (EEG) patterns during sleep and wakefulness may be informative. Here we hypothesise that abnormal EEG patterns of sleep and wakefulness may serve as predictive and diagnostic markers for postoperative delirium. Such abnormal EEG patterns would mechanistically link disrupted thalamocortical connectivity to this important clinical syndrome.

METHODS AND ANALYSIS

P-DROWS-E (Prognosticating Delirium Recovery Outcomes Using Wakefulness and Sleep Electroencephalography) is a 220-patient prospective observational study. Patient eligibility criteria include those who are English-speaking, age 60 years or older and undergoing elective cardiac surgery requiring cardiopulmonary bypass. EEG acquisition will occur 1-2 nights preoperatively, intraoperatively, and up to 7 days postoperatively. Concurrent with EEG recordings, two times per day postoperative Confusion Assessment Method (CAM) evaluations will quantify the presence and severity of delirium. EEG slow wave activity, sleep spindle density and peak frequency of the posterior dominant rhythm will be quantified. Linear mixed-effects models will be used to evaluate the relationships between delirium severity/duration and EEG measures as a function of time.

ETHICS AND DISSEMINATION

P-DROWS-E is approved by the ethics board at Washington University in St. Louis. Recruitment began in October 2018. Dissemination plans include presentations at scientific conferences, scientific publications and mass media.

TRIAL REGISTRATION NUMBER

NCT03291626.

Viability and validity of the bispectral index to measure sleep in patients in the intensive care unit

Objective

To investigate the viability of the bispectral index in the sleep evaluation of critically ill patients and to quantify the associations of sleep parameters measured by this index with the Richards-Campbell Sleep Questionnaire and environmental noise.

Methods

This was a cross-sectional observational study that evaluated critically ill adults with diseases of low or moderate severity. The following were measured: total sleep volume and time, deep sleep volume and time, continuous sleep volume and time, sleep onset latency, and environmental sound pressure level. The subjective perception of sleep was evaluated with the Richards-Campbell Sleep Questionnaire the morning after each night of observation.

Results

Patients had a low total sleep time (234 minutes), a predominance of superficial sleep stages, and little deep sleep (1.7 minutes). The total, deep, and continuous sleep volumes were 3,679, 9.4, and 3,143 (bispectral index units × minutes), respectively. The sleep latency was 94 minutes. The mean score of the Richards-Campbell Sleep Questionnaire was 57.9. Total sleep volume, total sleep time, and continuous sleep volume were weakly correlated with the Richards-Campbell Sleep Questionnaire depth of sleep domain score, overall sleep quality domain score, and total score. Total volume, total time, and continuous volume were moderately correlated with the occurrence of awakenings domain score.

Conclusion

The bispectral index is an instrument with limited viability to monitor the sleep of lucid patients and patients with low to moderate disease severity in the intensive care unit. Patients with higher total sleep volume, total sleep time, and continuous sleep volume had better overall sleep perception.

A Systematic Review of Sleep Measurement in Critically Ill Patients

Background: Clinical trialists and clinicians have used a number of sleep quality measures to determine the outcomes of interventions to improve sleep and ameliorate the neurobehavioral consequences of sleep deprivation in critically ill patients, but findings have not always been consistent. To elucidate the source of these consistencies, an important consideration is responsiveness of existing sleep measures. The purpose of an evaluative measure is to describe a construct of interest in a specific population, and to measure the extent of change in the construct over time. This systematic literature review identified measures of sleep quality in critically ill adults hospitalized in the Intensive Care Unit (ICU), and assessed their measurement properties, strengths and weaknesses, clinical usefulness, and responsiveness. We also recommended modifications, including new technology, that may improve clinical usefulness and responsiveness of the measures in research and practice.

Methods: CINAHAL, PubMed/Medline, and Cochrane Library were searched from January 1, 2000 to February 1, 2020 to identify studies that evaluated sleep quality in critically ill patients.

Results: Sixty-two studies using polysomnography (PSG) and other electroencephalogram-based methods, actigraphy, clinician observation, or patient perception using questionnaires were identified and evaluated. Key recommendations are: standard criteria are needed for scoring PSG in ICU patients who often have atypical brain waves; studies are too few, samples sizes too small, and study duration too short for recommendations on electroencephalogram-based measures and actigraphy; use the Sleep Observation Tool for clinician observation of sleep; and use the Richards Campbell Sleep Questionnaire to measure patient perception of sleep.

Conclusions: Measuring the impact of interventions to prevent sleep deprivation requires reliable and valid sleep measures, and investigators have made good progress developing, testing, and applying these measures in the ICU. We recommend future large, multi-site intervention studies that measure multiple dimensions of sleep, and provide additional evidence on instrument reliability, validity, feasibility and responsiveness. We also encourage testing new technologies to augment existing measures to improve their feasibility and accuracy.

Neurologic Manifestations of Systemic Disease: Sleep Disorders

Purpose of review

Sleep is intimately involved in overall health and wellbeing. We provide a comprehensive report on the interplay between systemic diseases and sleep to optimize the outcomes of systemic disorders.

Recent findings

Spanning the categories of endocrinologic disorders, metabolic/toxic disturbances, renal, cardiovascular, pulmonary, gastrointestinal, infectious diseases, autoimmune disorders, malignancy, and critical illness, the review highlights the prevalent coexisting pathology of sleep across the spectrum of systemic disorders. Although it is rare that treating a sleep symptom can cure disease, attention to sleep may improve quality of life and may mitigate or improve the underlying disorder. Recent controversies in assessing the cardiovascular relationship with sleep have called into question some of the benefits of treating comorbid sleep disorders, thereby highlighting the need for an ongoing rigorous investigation into how sleep interplays with systemic diseases.

Summary

Systemic diseases often have sleep manifestations and this report will help the clinician identify key risk factors linking sleep disorders to systemic diseases so as to optimize the overall care of the patient.

Sleep and Delirium in Older Adults

Purpose of Review

Poor sleep and delirium are common in older patients but recognition and management are challenging, particularly in the intensive care unit (ICU) setting. The purpose of this review is to highlight current research on these conditions, their inter-relationship, modes of measurement, and current approaches to management.

Recent Findings

Sleep deprivation and delirium are closely linked, with shared clinical characteristics, risk factors, and neurochemical abnormalities. Acetylcholine and dopamine are important neurochemicals in the regulation of sleep and wakefulness and their dysregulation has been implicated in development of delirium. In the hospital setting, poor sleep and delirium are associated with adverse outcomes; non-pharmacological interventions are recommended, but tend to be resource intensive and hindered by a lack of reliable sleep measurement tools. Delirium is easier to identify, with validated tools available in both ICU and non-ICU settings; however, an optimal treatment approach remains unclear. Antipsychotics are used widely to prevent and treat delirium, although the efficacy data are equivocal. Bundled non-pharmacologic approaches represent a promising framework for prevention and management.

Summary

Poor sleep and delirium are common problems in older patients. While these phenomena appear linked, a causal relationship is not clearly established. At present, there are no established sleep-focused guidelines for preventing or treating delirium. Novel interventions are needed that address poor sleep and delirium, particularly in older adults.

The role of suvorexant in the prevention of delirium during acute hospitalization: A systematic review

PURPOSE

To assess the efficacy and safety of suvorexant for the prevention of delirium during acute hospitalization.

MATERIALS AND METHODS

Pubmed (1946 to December 2019) and Embase (1947 to December 2019) were queried using the search term combination: delirium, confusion, cognitive defect, encephalopathy, critically ill patient, critical illness, or hospitalization and suvorexant or orexin receptor antagonist. Studies analyzed for relevance evaluated clinical outcomes of patients treated with suvorexant for prevention of delirium. Studies appropriate to the objective were evaluated, including two randomized controlled trials and four retrospective studies.

RESULTS

In acutely hospitalized patients, treatment with suvorexant 15 to 20 mg alone or in combination with ramelteon resulted in a reduction in development of delirium, time until delirium onset, and length of hospital stay. When assessed, suvorexant was well tolerated and adverse effects were no worse than placebo.

CONCLUSION

Based on the reviewed literature, suvorexant has shown positive outcomes in the prevention of delirium during an acute hospitalization. Larger trials comparing the efficacy of suvorexant to other sleep modulating options are necessary to further delineate its role for the prevention of delirium.

Internal clock and the surgical ICU patient

PURPOSE OF REVIEW

The alteration of circadian rhythms in the postoperative period has been demonstrated to influence the outcomes. With this narrative review we would revise how anesthesia, surgery and intensive care can interfere with the circadian clock, how this could impact on the postsurgical period and how to limit the disruption of the internal clock.

RECENT FINDINGS

Anesthesia affects the clock in relation to the day-time administration and the type of anesthetics, N-methyl-D-aspartate receptor antagonists or gamma-aminobutyric acid receptors agonists. Surgery causes stress and trauma with consequent alteration in the circadian release of cortisol, cytokines and melatonin. ICU represents a further challenge for the patient internal clock because of sedation, immobility, mechanical ventilation and alarms noise.

SUMMARY

The synergic effect of anesthesia, surgery and postoperative intensive care on circadian rhythms require a careful approach to the patient considering a role for therapies and interventions aimed to re-establish the normal circadian rhythms. Over time, approach like the Awakening and Breathing Coordination, Delirium Monitoring and Management, Early Mobility and Family engagement and empowerment bundle can implement the clinical practice.

Use of actigraphy to characterize inactivity and activity in patients in a medical ICU

BACKGROUND

In the intensive care unit (ICU), inactivity is common, contributing to ICU-acquired weakness and poor outcomes. Actigraphy may be useful for measuring activity in the ICU.

OBJECTIVES

To use actigraphy to characterize inactivity and activity in critically ill patients.

METHODS

This prospective observational study involved 48-h wrist actigraphy in medical ICU (MICU) patients, with activity data captured across 30-s epochs. Inactivity (zero-activity epochs) and activity (levels of non-zero activity) were summarized across key patient (e.g., age) and clinical (e.g., mechanical ventilation status) variables, and compared using multivariable regression.

RESULTS

Overall, 189,595 30-s epochs were collected in 34 MICU patients. Zero-activity (inactivity) comprised 122,865 (65%) of epochs; these epochs were 24% and 13% more prevalent, respectively, in patients receiving mechanical ventilation (versus none, p < 0.001) and in the highest (versus lowest) organ failure score tertile (p = 0.03). Ambulatory (versus non-ambulatory) patients exhibited more non-zero activity (35 more movements per epoch, p < 0.001), while those in the highest (versus lowest) organ failure score tertile exhibited less activity (22 fewer movements per epoch, p = 0.03). Significant inactivity/activity differences were not observed when evaluated based on age, sedation, or restraint status.

CONCLUSIONS

Actigraphy demonstrated that MICU patients are profoundly inactive, including those who are young, non-sedated and non-restrained. Hence, ICU-specific, non-patient-related factors may contribute to inactivity, an issue requiring further investigation.

Validity of an under-mattress sensor for objective sleep measurement in critically ill patients: a prospective observational study

Background

Considering the adverse effects of sleep disturbance in critical care settings, accurate assessment could aid therapy; however, methodological inadequacies mean that no viable option is currently available. Research in healthy population has recently shown that a non-wearable sleep measurement device placed under the mattress of the bed could be beneficial in intensive care settings. Therefore, we aimed to validate this device compared with polysomnography (PSG) and to assess how it related to subjective sleep evaluations.

Methods

This observational study measured the sleep of critically ill adult patients. The primary goal was to validate the Nemuri SCAN (NSCAN; Paramount Bed Co., Ltd., Tokyo, Japan) against the reference standard PSG for 24 h. The secondary goal was to evaluate the association between the objective parameters obtained from NSCAN and PSG and the subjective report data obtained using the Richards–Campbell Sleep Questionnaire (RCSQ) for the nighttime.

Results

Eleven participants were evaluated. The median of the total sleep time scored by PSG was 456.0 (353.0–517.5) min during the nighttime and 305.0 (186.2–542.5) min during the daytime. PSG over 24 h revealed significant decreases in restorative sleep, with excessive daytime sleep, but with a normal quantity of nighttime sleep. The agreement, sensitivity, and specificity rates (with 95% confidence intervals) for the NSCAN compared with PSG were 68.4% (67.9–69.0%), 90.1% (89.7–90.6%), and 38.7% (37.9–39.7%), respectively. The median RCSQ value when subjectively evaluating nighttime sleep was 68.0 (26.3–83.5); this showed no correlation with the NSCAN sleep parameters, despite a positive correlation with the ratio of the stage N2 isolated or combined with restorative sleep in the PSG assessment.

Conclusions

NSCAN had moderate agreement, high sensitivity, and poor specificity in intensive care settings, which is most likely due to its inability to identify immobile wakefulness often observed in critically ill patients or sleep depth. This remains a barrier to its use in the assessment of subjective sleep quality.

Trial registration

This investigation was part of an interventional trial registered with the University Hospital Medical Information Network Individual Clinical Trials Registry (UMIN000026350, http://www.umin.ac.jp/icdr/index-j.html) on March 1, 2017.

Atypical Sleep and Postoperative Delirium in the Cardiothoracic Surgical Intensive Care Unit: A Pilot Prospective Study

PURPOSE

Postoperative delirium (POD) is a very common and serious neurological complication in patients admitted to the cardiothoracic surgical intensive care unit (CSICU). We aimed to identify a novel potential sleep-based marker for POD and investigate the relevance between atypical sleep and POD.

PATIENTS AND METHODS

This was a prospective, observational study of patients admitted to the CSICU between December 2019 and February 2020 at our center. Sleep characteristics from 21:00 on postoperative day 1 to 07:00 on postoperative day 2 were assessed using polysomnography (PSG). POD from the end of PSG monitoring until postoperative day 5 was evaluated using the Confusion Assessment Method for the Intensive Care Unit.

RESULTS

This analysis included 20 patients admitted to the CSICU. The incidence of atypical sleep was 45.0%. Compared to patients without delirium, those with delirium had less delta power, less percentage REM sleep, and a higher proportion of atypical sleep and REM sleep loss (P < 0.05).

CONCLUSION

The presence of atypical sleep and the absence of REM sleep were associated with POD in patients admitted to the CSICU.

Sleep and Delirium in Adults Who Are Critically Ill: A Contemporary Review

Sleep is important to health and well-being, and studies in healthy adults have demonstrated that sleep deprivation impacts respiratory, immune, and cognitive function. Historically, because of the nature of critical illness, sleep has not been considered a priority for patient care in the ICU. More recently, research has demonstrated that sleep is markedly abnormal in patients who are critically ill. In addition, there is often disruption of circadian rhythms. Delirium is a syndrome of acute alteration in mental status that occurs in the setting of contributing factors such as serious illness, medication, and drug or alcohol intoxication or withdrawal. Delirium is a frequent occurrence in critical illness, and research has demonstrated several adverse outcomes associated with delirium including persistent cognitive impairment and increased mortality. Sleep deprivation and delirium share many common symptoms. The similarity in symptoms between sleep disruption and delirium have prompted experts to draw links between the two and question both the relationship and its direction. In addition, the inclusion of sleep disturbance to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition in its constellation of symptoms used in diagnosing delirium has increased awareness of the link between sleep and delirium. This paper will review the literature on sleep in critical illness and the potential mechanisms and pathways that may connect sleep and delirium.

Actigraphy to Evaluate Sleep in the Intensive Care Unit. A Systematic Review

RATIONALE

Poor sleep quality is common in the intensive care unit (ICU) and may be associated with adverse outcomes. Hence, ICU-based efforts to promote sleep are gaining attention, motivating interest in methods to measure sleep in critically ill patients. Actigraphy evaluates rest and activity by algorithmically processing gross motor activity data, usually collected by a noninvasive wristwatch-like accelerometer device. In critically ill patients, actigraphy has been used as a surrogate measure of sleep; however, its use has not been systematically reviewed.

OBJECTIVES

To conduct a systematic review of ICU-based studies that used actigraphy as a surrogate measure of sleep, including its feasibility, validity, and reliability as a measure of sleep in critically ill patients.

METHODS

We searched PubMed, EMBASE, CINAHL, Proquest, and Web of Science for studies that used actigraphy to evaluate sleep in five or more patients in an ICU setting.

RESULTS

Our search yielded 4,869 citations, with 13 studies meeting eligibility criteria. These 13 studies were conducted in 10 countries, and eight (62%) were published since 2008. Across the 13 studies, the mean total sleep time of patients in the ICU, as estimated using actigraphy, ranged from 4.4 to 7.8 hours at nighttime and from 7.1 to 12.1 hours over a 24-hour period, with 1.4 to 49.0 mean nocturnal awakenings and a sleep efficiency of 61 to 75%. When compared side-by-side with other measures of sleep (polysomnography, nurse assessments, and patient questionnaires), actigraphy consistently yielded higher total sleep time and sleep efficiency, fewer nighttime awakenings (vs. polysomnography), and more overall awakenings (vs. nurse assessment and patient questionnaires). None of the studies evaluated the association between actigraphy-based measures of sleep and outcomes of patients in the ICU.

CONCLUSIONS

In critically ill patients, actigraphy is being used more frequently as a surrogate measure of sleep; however, because actigraphy only measures gross motor activity, its ability to estimate sleep is limited by the processing algorithm used. Prior ICU-based studies involving actigraphy were heterogeneous and lacked data regarding actigraphy-based measures of sleep and patient outcomes. Larger, more rigorous and standardized studies are needed to better understand the role of actigraphy in evaluating sleep and sleep-related outcomes in critically ill patients.

Clinical Practice Guidelines for the Prevention and Management of Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU

OBJECTIVE

To update and expand the 2013 Clinical Practice Guidelines for the Management of Pain, Agitation, and Delirium in Adult Patients in the ICU.

DESIGN

Thirty-two international experts, four methodologists, and four critical illness survivors met virtually at least monthly. All section groups gathered face-to-face at annual Society of Critical Care Medicine congresses; virtual connections included those unable to attend. A formal conflict of interest policy was developed a priori and enforced throughout the process. Teleconferences and electronic discussions among subgroups and whole panel were part of the guidelines' development. A general content review was completed face-to-face by all panel members in January 2017.

METHODS

Content experts, methodologists, and ICU survivors were represented in each of the five sections of the guidelines: Pain, Agitation/sedation, Delirium, Immobility (mobilization/rehabilitation), and Sleep (disruption). Each section created Population, Intervention, Comparison, and Outcome, and nonactionable, descriptive questions based on perceived clinical relevance. The guideline group then voted their ranking, and patients prioritized their importance. For each Population, Intervention, Comparison, and Outcome question, sections searched the best available evidence, determined its quality, and formulated recommendations as "strong," "conditional," or "good" practice statements based on Grading of Recommendations Assessment, Development and Evaluation principles. In addition, evidence gaps and clinical caveats were explicitly identified.

RESULTS

The Pain, Agitation/Sedation, Delirium, Immobility (mobilization/rehabilitation), and Sleep (disruption) panel issued 37 recommendations (three strong and 34 conditional), two good practice statements, and 32 ungraded, nonactionable statements. Three questions from the patient-centered prioritized question list remained without recommendation.

CONCLUSIONS

We found substantial agreement among a large, interdisciplinary cohort of international experts regarding evidence supporting recommendations, and the remaining literature gaps in the assessment, prevention, and treatment of Pain, Agitation/sedation, Delirium, Immobility (mobilization/rehabilitation), and Sleep (disruption) in critically ill adults. Highlighting this evidence and the research needs will improve Pain, Agitation/sedation, Delirium, Immobility (mobilization/rehabilitation), and Sleep (disruption) management and provide the foundation for improved outcomes and science in this vulnerable population.