Sleep and Circadian Rhythms in Survivors of Acute Respiratory Failure

Sleep and Circadian Health of Critical Survivors: A 12-Month Follow-Up Study

OBJECTIVES

To investigate the sleep and circadian health of critical survivors 12 months after hospital discharge and to evaluate a possible effect of the severity of the disease within this context.

DESIGN

Observational, prospective study.

SETTING

Single-center study.

PATIENTS

Two hundred sixty patients admitted to the ICU due to severe acute respiratory syndrome coronavirus 2 infection.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The cohort was composed of 260 patients (69.2% males), with a median (quartile 1-quartile 3) age of 61.5 years (52.0-67.0 yr). The median length of ICU stay was 11.0 days (6.00-21.8 d), where 56.2% of the patients required invasive mechanical ventilation (IMV). The Pittsburgh Sleep Quality Index (PSQI) revealed that 43.1% of the cohort presented poor sleep quality 12 months after hospital discharge. Actigraphy data indicated an influence of the disease severity on the fragmentation of the circadian rest-activity rhythm at the 3- and 6-month follow-ups, which was no longer significant in the long term. Still, the length of the ICU stay and the duration of IMV predicted a higher fragmentation of the rhythm at the 12-month follow-up with effect sizes (95% CI) of 0.248 (0.078-0.418) and 0.182 (0.005-0.359), respectively. Relevant associations between the PSQI and the Hospital Anxiety and Depression Scale (rho = 0.55, anxiety; rho = 0.5, depression) as well as between the fragmentation of the rhythm and the diffusing lung capacity for carbon monoxide (rho = -0.35) were observed at this time point.

CONCLUSIONS

Our findings reveal a great prevalence of critical survivors presenting poor sleep quality 12 months after hospital discharge. Actigraphy data indicated the persistence of circadian alterations and a possible impact of the disease severity on the fragmentation of the circadian rest-activity rhythm, which was attenuated at the 12-month follow-up. This altogether highlights the relevance of considering the sleep and circadian health of critical survivors in the long term.

Association between Acute Respiratory Distress Syndrome Due to COVID-19 and Long-Term Sleep and Circadian Sleep-Wake Disorders

Current studies agree on the impact of sleep and circadian rest-activity rhythm alterations in acute respiratory distress syndrome (ARDS) survivors. However, research on the duration of this impact is scarce. In this study, we evaluate the impact of ARDS on the sleep and circadian rest-activity rhythm of COVID-19 survivors twelve months after hospital discharge. This is a prospective study including COVID-19 survivors with and without ARDS during hospitalization. Data was collected four and twelve months after hospital discharge. The interventions included one-week wrist actigraphy and a home sleep apnea test (HSAT), and evaluations were conducted according to the Pittsburgh sleep quality index (PSQI), Epworth sleepiness scale (ESS), and insomnia severity index (ISI). Fifty-two patients were evaluated (ARDS = 31 and non-ARDS = 21); they had a median age of 49.0 [39.0;57.2] years and 53.8% were male. After twelve months, 91.3% presented poor sleep quality, 58.7% presented insomnia, 50% presented daytime somnolence, and 37% presented comorbid insomnia and obstructive sleep apnea (COMISA). No significant improvement was observed in relation to sleep or the circadian rest-activity rhythm between four and twelve months. A tendency of poor sleep quality, insomnia, daytime somnolence, and COMISA was observed. Finally, there was no significant impact on the circadian rest-activity rhythm between four and twelve months or between the groups.

Weak synchronization can alter circadian period length: implications for aging and disease conditions

The synchronization of multiple oscillators serves as the central mechanism for maintaining stable circadian rhythms in physiology and behavior. Aging and disease can disrupt synchronization, leading to changes in the periodicity of circadian activities. While our understanding of the circadian clock under synchronization has advanced significantly, less is known about its behavior outside synchronization, which can also fall within a predictable domain. These states not only impact the stability of the rhythms but also modulate the period length. In C57BL/6 mice, aging, diseases, and removal of peripheral circadian oscillators often result in lengthened behavioral circadian periods. Here, we show that these changes can be explained by a surprisingly simple mathematical relationship: the frequency is the reciprocal of the period, and its distribution becomes skewed when the period distribution is symmetric. The synchronized frequency of a population in the skewed distribution and the macroscopic frequency of combined oscillators differ, accounting for some of the atypical circadian period outputs observed in networks without synchronization. Building on this finding, we investigate the dynamics of circadian outputs in the context of aging and disease, where synchronization is weakened.

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.

Dynamic prevalence of sleep disturbance among critically ill patients in intensive care units and after hospitalisation: A systematic review and meta-analysis

BACKGROUND

Sleep disturbance is a common complaint among critically ill patients in intensive care units and after hospitalisation. However, the prevalence of sleep disturbance among critically ill patients varies widely.

OBJECTIVE

To estimate the prevalence of sleep disturbance among critically ill patients in the intensive care unit and after hospitalisation.

METHODS

Electronic databases were searched from their inception until 15 August 2022. Only observational studies with cross-sectional, prospective, and retrospective designs investigating sleep disturbance prevalence among critically ill adults (aged ≥ 18 years) during intensive care unit stay and after hospitalisation were included.

RESULTS

We found 13 studies investigating sleep disturbance prevalence in intensive care units and 14 investigating sleep disturbance prevalence after hospitalisation, with 1,228 and 3,065 participants, respectively. The prevalence of sleep disturbance during an ICU stay was 66 %, and at two, three, six and ≥ 12 months after hospitalisation was 64 %, 49 %, 40 %, and 28 %, respectively. Studies using the Richards-Campbell Sleep Questionnaire detected a higher prevalence of sleep disturbance among patients in intensive care units than non-intensive care unit specific questionnaires; studies reported comparable sleep disturbance prevalence during intensive care stays for patients with and without mechanical ventilation.

CONCLUSION

Sleep disturbance is prevalent in critically ill patients admitted to an intensive care unit and persists for up to one year after hospitalisation, with prevalence ranging from 28 % to 66 %. The study results highlight the importance of implementing effective interventions as early as possible to improve intensive care unit sleep quality.

Rest-Activity Rhythm Fragmentation and Weaker Circadian Strength Are Associated With Cognitive Impairment in Survivors of Acute Respiratory Failure

Background: Survivors of acute respiratory failure (ARF) experience long-term cognitive impairment and circadian rhythm disturbance after hospital discharge. Although prior studies in aging and neurodegenerative diseases indicate actigraphy-estimated rest-activity circadian rhythm disturbances are risk factors for cognitive impairment, it is unclear if this applies to ARF survivors. This study explored the relationships of actigraphy-estimated rest-activity circadian rhythms with cognitive functioning in ARF survivors at 3 months after discharge. Methods: 13 ARF survivors (mean age 51 years and 69% males) completed actigraphy and sleep diaries for 9 days, followed by at-home neuropsychological assessment. Principal component factor analysis created global cognition and circadian rhythm variables, and these first components were used to examine the global relationships between circadian rhythm and cognitive measure scores. Results: Global circadian function was associated with global cognition function in ARF survivors (r = .70, p = .024) after adjusting for age, education, and premorbid cognition. Also, greater fragmented rest-activity circadian rhythm (estimated by intradaily variability, r = .85, p = .002), and weaker circadian strength (estimated by amplitude, r = .66, p = .039; relative strength, r = .70, p = .024; 24-h lag serial autocorrelation, r = .67, p = .035), were associated with global cognition and individual cognitive tests. Conclusions: These results suggest circadian rhythm disturbance is associated with poorer global cognition in ARF survivors. Future prospective research with larger samples is needed to confirm these results and increase understanding of the relationship between disrupted circadian rhythms and cognitive impairment among ARF survivors.

Detecting the Effect Size of Weather Conditions on Patient-Reported Outcome Measures (PROMs)

One of the next frontiers in medical research, particularly in orthopaedic surgery, is personalized treatment outcome prediction. In personalized medicine, treatment choices are adjusted for the patient based on the individual's and their disease's distinct features. A high-value and patient-centered health care system requires evaluating results that integrate the patient's viewpoint. Patient-reported outcome measures (PROMs) are widely used to shed light on patients' perceptions of their health status after an intervention by using validated questionnaires. The aim of this study is to examine whether meteorological or light (night vs. day) conditions affect PROM scores and hence indirectly affect health-related outcomes. We collected scores for PROMs from questionnaires completed by patients (N = 2326) who had undergone hip and knee interventions between June 2017 and May 2020 at the IRCCS Orthopaedic Institute Galeazzi (IOG), Milan, Italy. Nearest neighbour propensity score (PS) matching was applied to ensure the similarity of the groups tested under the different weather-related conditions. The exposure PS was derived through logistic regression. The data were analysed using statistical tests (Student's t-test and Mann-Whitney U test). According to Cohen's effect size, weather conditions may affect the scores for PROMs and, indirectly, health-related outcomes via influencing the relative humidity and weather-related conditions. The findings suggest avoiding PROMs' collection in certain conditions if the odds of outcome-based underperformance are to be minimized. This would ensure a balance between costs for PROMs' collection and data availability.

Loss of thyroid gland circadian PER2 rhythmicity in aged mice and its potential association with thyroid cancer development

Molecular clocks operate in peripheral tissues, including endocrine glands, and play important regulatory roles in this context. However, potential age-related changes in the expression rhythmicity of clock genes and the effects of these changes on the thyroid gland remain unknown. In the present study, we evaluated the expression rhythmicity of peripheral thyroid clock genes in aged mice using RNA-seq transcriptomic analysis in young (3.5-month) versus aged (20-month) mice. In addition, we determined the cellular effects of silencing of PER2, a major clock gene regulator, in human thyroid cell lines. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that differentially expressed genes (DEGs) in the thyroid glands of aged mice were involved in mitogen-activated protein kinase (MAPK) signaling, chemokine signaling, circadian entrainment, PI3K/AKT signaling, and Apelin signaling. The expression of circadian clock genes Arntl/Bmal1 was significantly downregulated in thyroid glands of aged mice, whereas the expression of genes involved in regulation of cell proliferation, migration, and tumorigenesis was upregulated. Peripheral thyroid clock genes, particularly Per mRNA and PER2 protein, were downregulated in the thyroid glands of aged mice, and circadian oscillation of these genes was declined. Knockdown of the circadian clock gene PER2 in human thyroid follicular cells induced AP-1 activity via JNK MAPK signaling activation, which increased cell proliferation. Furthermore, the aging-related loss of PER2 circadian oscillation activated the AP-1 transcription factor via the JNK MAPK pathway, which could contribute to thyroid hyperplasia, a common age-related condition.

Circadian rest-activity misalignment in critically ill medical intensive care unit patients

Circadian alignment of rest-activity rhythms is an essential biological process that may be vulnerable to misalignment in critically ill patients. We evaluated circadian rest-activity rhythms in critically ill patients and their association with baseline (e.g. age) and clinical (e.g. mechanical ventilation status) variables, along with intensive care unit light-dark cycles. Using wrist actigraphy, we collected 48-hr activity and light exposure data from critically ill patients in a tertiary care medical intensive care unit. We evaluated circadian rest-activity rhythms using COSINOR and non-parametric circadian rhythm analysis models, and stratified these data across baseline and clinical variables. We used linear regression to evaluate the association of circadian rest-activity and light-dark exposure rhythms. In COSINOR and non-parametric circadian rhythm analysis analyses, the 34 medical intensive care unit patients completing 48-hr actigraphy recordings exhibited mean MESOR (mean activity levels of a fitted curve) and amplitudes of 0.50 ± 0.32 and 0.20 ± 0.19 movements per 30-s epoch, with high interdaily variability. Patients who were older, mechanically ventilated, sedated, restrained and with higher organ failure scores tended to exhibit greater circadian rest-activity misalignment, with three of 34 (9%) patients exhibiting no circadian rhythmicity. Circadian light-dark exposure misalignment was observed as well and was associated with rest-activity misalignment (p = 0.03). Critically ill patients in our MICU experienced profound circadian rest-activity misalignment, with mostly weak or absent rhythms, along with circadian light-dark exposure misalignment. Potentially modifiable factors contributing to rest-activity misalignment (i.e. mechanical ventilation, restraints, low daytime light levels) highlight possible targets for future improvement efforts.

Intermittent feeding and circadian rhythm in critical illness

PURPOSE OF REVIEW

Circadian rhythms, i.e., periodic oscillations in internal biological processes, modulate metabolic processes such as hormonal signalling, nutrient absorption, and xenobiotic detoxification. Meal timing is a strong entraining cue for peripheral clocks in various organs, and eating out of circadian phases can impair glucose, gastrointestinal, and muscle metabolism. Sleep/wake cycles and circadian rhythms are extremely disrupted during critical illness. Timing of nutritional support may help preserve circadian rhythms and improve post-Intensive Care Unit (ICU) recovery. This review summarises circadian disruptors during ICU admission and evaluates the potential benefits of intermittent feeding on metabolism and circadian rhythms.

RECENT FINDINGS

Rhythmic expression of core clock genes becomes rapidly disturbed during critical illness and remains disturbed for weeks. Intermittent, bolus, and cyclic enteral feeding have been directly compared to routine continuous feeding, yet no benefits on glycaemic control, gastrointestinal tolerance, and muscle mass have been observed and impacts of circadian clocks remain untested.

SUMMARY

Aligning timing of nutritional intake, physical activity, and/or medication with circadian rhythms are potential strategies to reset peripheral circadian rhythms and may enhance ICU recovery but is not proven beneficial yet. Therefore, selecting intermittent feeding over continuous feeding must be balanced against the pros and cons of clinical practice.

Sleep and Circadian Health of Critical COVID-19 Survivors 3 Months After Hospital Discharge

To evaluate the sleep and circadian rest-activity pattern of critical COVID-19 survivors 3 months after hospital discharge.

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.

Occurrence and Long-term Prognosis of Insomnia Disorder among Survivors of Acute Respiratory Distress Syndrome in South Korea

RATIONALE

As a most common type of sleep disorder, insomnia disorder can develop as a sequela among acute respiratory distress syndrome (ARDS) survivors. However, insomnia prevalence, its associated factors, and its impact on long-term survival remain controversial.

OBJECTIVES

This study aimed to investigate insomnia prevalence and its associated factors among ARDS survivors. We also examined the association between insomnia and 2-year all-cause mortality.

METHODS

The National Health Insurance Database of South Korea was used for this nationwide cohort study. We included adult patients (≥18 years old) admitted to intensive care units for ARDS treatment from January 1, 2010, to December 31, 2018, and survived for ≥1 year after diagnosis, defined as ARDS survivors. ARDS survivors diagnosed with insomnia disorder before ARDS diagnosis were defined as the pre-ARDS insomnia disorder group, whereas those who had no history of insomnia disorder but were newly diagnosed with insomnia disorder within 1 year of diagnosis of ARDS were defined as the post-ARDS insomnia disorder group.

RESULTS

A total of 4,452 ARDS survivors were included in this study, with 895 patients (20.1%) in the pre-ARDS insomnia disorder group and 536 (12.6%) patients in the post-ARDS insomnia disorder group. In the multivariable logistic regression analysis, delirium occurrence (odds ratio [OR]:1.61, 95% confidence interval [CI]: 1.24-2.10; P<0.001), underlying anxiety disorder (OR:1.34, 95% CI: 1.08-1.66; P=0.007), depression (OR: 1.48, 95% CI: 1.17-1.86; P=0.001), and substance abuse (OR:1.51, 95% CI: 1.01-2.26; P=0.042) were associated with a higher prevalence of post-ARDS insomnia disorder. In multivariable Cox regression analysis, the pre-ARDS insomnia disorder and post-ARDS insomnia disorder groups were associated with 1.33-fold (hazard ratio [HR]:1.33, 95% CI: 1.08-1.64; P=0.007) and 1.36-fold (HR:1.36, 95% CI: 1.06-1.74; P=0.016) increased prevalence of 2-year all-cause mortality among ARDS survivors, respectively.

CONCLUSIONS

At 1 year after diagnosis of ARDS, 12.6% of ARDS survivors were newly diagnosed with insomnia disorder in South Korea. Delirium and underlying psychiatric illness (anxiety disorder, depression, and substance abuse) were potential risk factors for the diagnosis of post-ARDS insomnia disorder. Moreover, both pre-and post-ARDS insomnia disorders were associated with 2-year all-cause mortality among ARDS survivors.

A Prospective Study Evaluating Sleep Quality and Disorders in Post-ARDS Patients

Introduction

Critically ill patients are predisposed to developing sleep disorders due to multiple factors like pre-existing sleep disorders, severe acute illness, sleep-altering medical interventions, and the disturbing intensive care unit (ICU) environment. In the current study, a multi-modality approach has been attempted to capture the different aspects of sleep disturbances, including insomnia (using ISI), daytime sleepiness (using ESS), sleep quality (using PSQI), sleep architecture, and SDB (using PSG).

Materials and Methods

The eligible ARDS survivor patients were updated about the study's design prior to hospital discharge. At admission, data regarding demographic details, clinical history, etiology of ARDS, and PaO₂/FiO₂ (P/F) ratio at presentation, Acute Physiology and Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores was collected. All enrolled patients were evaluated twice (early-within 7 days of admission and late-after 6 weeks of discharge) by the Richards-Campbell Sleep Questionnaire (RCSQ), Insomnia severity index (ISI), and level 1 PSG. Additionally, ESS questionnaire and the Pittsburgh Sleep Quality Index (PSQI) were also recorded in late evaluation. Abnormal sleep was defined if one or more of the following characteristics met: ISI > 15, ESS > 10, global PSQI > 5, AHI ≥ 5 events/h.

Results

Thirty patients were recruited out of the total of 88 ARDS patients screened at admission. The median (IQR) PaO₂/FiO₂ ratio and APACHE II scores were 176 (151-191.5) and 14 (14-16), respectively. The median (IQR) duration of stay in the ICU was 10 (7.3-19.5) days. The median RCSQ score in the early and late evaluation was 42 and 69, respectively. The mean ISI score in the early evaluation was 16.67 ± 4.72, which decreased to 11.70 ± 5.03 in late evaluation (p < 0.05). ISI score > 15 (clinical insomnia) was found in 18 out of 30 subjects (60%) in early evaluation and 11 out of 30 (36%) in late evaluation. During the early evaluation, sleep efficiency was low (median 59.9% and predominantly N1 and N2) which improved in late evaluation (median 80.6%). Of the 30 patients, only 4 had AHI > 5 in early evaluation and none in late evaluation. Neither of P/F ratio, SOFA, and APACHE II scores did correlate with ICU events in the early and late evaluations. Regression analysis showed subjects with ICU stay more than 10 days, duration of IMV more than 7 days, Fentanyl more than 7 mg, duration of sedative use more than 7 days was independently associated with poor objective sleep quality (low sleep efficiency, low TST and high arousal index) during the early and late evaluations after ICU discharge compared to counterparts (p value < 0.05).

Conclusion

We conclude that sleep quality in ARDS survivors was poor within 7 days of ICU discharge, characterized by severe disruption of sleep architecture and sleep-disordered breathing. After 6 weeks of ICU discharge sleep quality showed significant improvement in the N3 stage and AHI, however persistent insomnia was observed even at 6 weeks. Therefore, prior identification of risk factors and early diagnosis of sleep quality disorders in post-ARDS patients is essential.

Post-intensive care syndrome after a critical COVID-19: cohort study from a Belgian follow-up clinic

Purpose

Many patients with coronavirus disease 2019 (COVID-19) required critical care. Mid-term outcomes of the survivors need to be assessed. The objective of this single-center cohort study was to describe their physical, cognitive, psychological, and biological outcomes at 3 months following intensive care unit (ICU)-discharge (M3).

Patients and methods

All COVID-19 adults who survived an ICU stay ≥ 7 days and attended the M3 consultation at our multidisciplinary follow-up clinic were involved. They benefited from a standardized assessment, addressing health-related quality of life (EQ-5D-3L), sleep disorders (PSQI), and the three principal components of post-intensive care syndrome (PICS): physical status (Barthel index, handgrip and quadriceps strength), mental health disorders (HADS and IES-R), and cognitive impairment (MoCA). Biological parameters referred to C-reactive protein and creatinine.

Results

Among the 92 patients admitted to our ICU for COVID-19, 42 survived a prolonged ICU stay and 32 (80%) attended the M3 follow-up visit. Their median age was 62 [49–68] years, 72% were male, and nearly half received inpatient rehabilitation following ICU discharge. At M3, 87.5% (28/32) had not regained their baseline level of daily activities. Only 6.2% (2/32) fully recovered, and had normal scores for the three MoCA, IES-R and Barthel scores. The main observed disorders were PSQI > 5 (75%, 24/32), MoCA < 26 (44%, 14/32), Barthel < 100 (31%, 10/32) and IES-R ≥ 33 (28%, 9/32). Combined disorders were observed in 13/32 (40.6%) of the patients. The EQ-5D-3L visual scale was rated at 71 [61–80]. A quarter of patients (8/32) demonstrated a persistent inflammation based on CRP blood level (9.3 [6.8–17.7] mg/L).

Conclusion

The burden of severe COVID-19 and prolonged ICU stay was considerable in the present cohort after 3 months, affecting both functional status and biological parameters. These data are an argument on the need for closed follow-up for critically ill COVID-19 survivors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00910-9.

Significant Unresolved Questions and Opportunities for Bioengineering in Understanding and Treating COVID-19 Disease Progression

COVID-19 is a disease that manifests itself in a multitude of ways across a wide range of tissues. Many factors are involved, and though impressive strides have been made in studying this novel disease in a very short time, there is still a great deal that is unknown about how the virus functions. Clinical data has been crucial for providing information on COVID-19 progression and determining risk factors. However, the mechanisms leading to the multi-tissue pathology are yet to be fully established. Although insights from SARS-CoV-1 and MERS-CoV have been valuable, it is clear that SARS-CoV-2 is different and merits its own extensive studies. In this review, we highlight unresolved questions surrounding this virus including the temporal immune dynamics, infection of non-pulmonary tissue, early life exposure, and the role of circadian rhythms. Risk factors such as sex and exposure to pollutants are also explored followed by a discussion of ways in which bioengineering approaches can be employed to help understand COVID-19. The use of sophisticated in vitro models can be employed to interrogate intercellular interactions and also to tease apart effects of the virus itself from the resulting immune response. Additionally, spatiotemporal information can be gleaned from these models to learn more about the dynamics of the virus and COVID-19 progression. Application of advanced tissue and organ system models into COVID-19 research can result in more nuanced insight into the mechanisms underlying this condition and elucidate strategies to combat its effects.