Clinical chronobiology: a timely consideration in critical care medicine

One Health: Circadian Medicine Benefits Both Non-human Animals and Humans Alike

Circadian biology's impact on human physical health and its role in disease development and progression is widely recognized. The forefront of circadian rhythm research now focuses on translational applications to clinical medicine, aiming to enhance disease diagnosis, prognosis, and treatment responses. However, the field of circadian medicine has predominantly concentrated on human healthcare, neglecting its potential for transformative applications in veterinary medicine, thereby overlooking opportunities to improve non-human animal health and welfare. This review consists of three main sections. The first section focuses on the translational potential of circadian medicine into current industry practices of agricultural animals, with a particular emphasis on horses, broiler chickens, and laying hens. The second section delves into the potential applications of circadian medicine in small animal veterinary care, primarily focusing on our companion animals, namely dogs and cats. The final section explores emerging frontiers in circadian medicine, encompassing aquaculture, veterinary hospital care, and non-human animal welfare and concludes with the integration of One Health principles. In summary, circadian medicine represents a highly promising field of medicine that holds the potential to significantly enhance the clinical care and overall health of all animals, extending its impact beyond human healthcare.

Using chronobiology-based second-generation artificial intelligence digital system for overcoming antimicrobial drug resistance in chronic infections

Antimicrobial resistance results from the widespread use of antimicrobial agents and is a significant obstacle to the effectiveness of these agents. Numerous methods are used to overcome this problem with moderate success. Besides efforts of antimicrobial stewards, several artificial intelligence (AI)-based technologies are being explored for preventing resistance development. These first-generation systems mainly focus on improving patients' adherence. Chronobiology is inherent in all biological systems. Host response to infections and pathogens activity are assumed to be affected by the circadian clock. This paper describes the problem of antimicrobial resistance and reviews some of the current AI technologies. We present the establishment of a second-generation AI chronobiology-based approach to help in preventing further resistance and possibly overcome existing resistance. An algorithm-controlled regimen that improves the long-term effectiveness of antimicrobial agents is being developed based on the implementation of variability in dosing and drug administration times. The method provides a means for ensuring a sustainable response and improved outcomes. Ongoing clinical trials determine the effectiveness of this second-generation system in chronic infections. Data from these studies are expected to shed light on a new aspect of resistance mechanisms and suggest methods for overcoming them.IMPORTANCE SECTIONThe paper presents the establishment of a second-generation AI chronobiology-based approach to help in preventing further resistance and possibly overcome existing resistance.Key messagesAntimicrobial resistance results from the widespread use of antimicrobial agents and is a significant obstacle to the effectiveness of these agents.We present the establishment of a second-generation AI chronobiology-based approach to help in preventing further resistance and possibly overcome existing resistance.

Evaluation of the sensory environment in a large tertiary ICU

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

TrACES of time: Transcriptomic analyses for the contextualization of evidential stains - Identification of RNA markers for estimating time-of-day of bloodstain deposition

Obtaining forensically relevant information beyond who deposited a biological stain on how and under which circumstances it was deposited is a question of increasing importance in forensic molecular biology. In the past few years, several studies have been produced on the potential of gene expression analysis to deliver relevant contextualizing information, e.g. on nature and condition of a stain as well as aspects of stain deposition timing. However, previous attempts to predict the time-of-day of sample deposition were all based on and thus limited by previously described diurnal oscillators. Herein, we newly approached this goal by applying current sequencing technologies and statistical methods to identify novel candidate markers for forensic time-of-day predictions from whole transcriptome analyses. To this purpose, we collected whole blood samples from ten individuals at eight different time points throughout the day, performed whole transcriptome sequencing and applied biostatistical algorithms to identify 81 mRNA markers with significantly differential expression as candidates to predict the time of day. In addition, we performed qPCR analysis to assess the characteristics of a subset of 13 candidate predictors in dried and aged blood stains. While we demonstrated the general possibility of using the selected candidate markers to predict time-of-day of sample deposition, we also observed notable variation between different donors and storage conditions, highlighting the relevance of employing accurate quantification methods in combination with robust normalization procedures.This study's results are foundational and may be built upon when developing a targeted assay for time-of-day predictions from forensic blood samples in the future.

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.

Uncoupled redox stress: how a temporal misalignment of redox-regulated processes and circadian rhythmicity exacerbates the stressed state

Diurnal and seasonal rhythmicity, entrained by environmental and nutritional cues, is a vital part of all life on Earth operating at every level of organization; from individual cells, to multicellular organisms, whole ecosystems and societies. Redox processes are intrinsic to physiological function and circadian regulation, but how they are integrated with other regulatory processes at the whole-body level is poorly understood. Circadian misalignment triggered by a major stressor (e.g. viral infection with SARS-CoV-2) or recurring stressors of lesser magnitude such as shift work elicit a complex stress response that leads to desynchronization of metabolic processes. This in turn challenges the system's ability to achieve redox balance due to alterations in metabolic fluxes (redox rewiring). We infer that the emerging 'alternative redox states' do not always revert readily to their evolved natural states; 'Long COVID' and other complex disorders of unknown aetiology are the clinical manifestations of such rearrangements. To better support and successfully manage bodily resilience to major stress and other redox challenges needs a clear perspective on the pattern of the hysteretic response for the interaction between the redox system and the circadian clock. Characterization of this system requires repeated (ideally continuous) recording of relevant clinical measures of the stress responses and whole-body redox state (temporal redox phenotyping). The human/animal body is a complex 'system of systems' with multi-level buffering capabilities, and it requires consideration of the wider dynamic context to identify a limited number of stress-markers suitable for routine clinical decision making. Systematically mapping the patterns and dynamics of redox biomarkers along the stressor/disease trajectory will provide an operational model of whole-body redox regulation/balance that can serve as basis for the identification of effective interventions which promote health by enhancing resilience.

Familiarity of Brazilian psychologists with basic concepts in sleep science and chronobiology

Desynchronization of circadian rhythms and sleep-wake patterns impacts biochemical, physiological, and behavioral functions, including mental processes. The complex relationship between circadian rhythms and mental health makes it challenging to determine causality between circadian desynchronization and mental disorders. Regarding the fact that psychologists act as the front line for initial mental health care, we aimed to assess the knowledge and use of sleep science and basic chronobiology by professional psychologists in Brazil. Data were collected via an online questionnaire completed by 1384 professional psychologists between October 2018 and May 2019. Our findings revealed that ±80% of psychologists reported that at least half of their patients presented some sleep-related complaints; however, only ±27% routinely inquired about sleep quality even in the absence of patient complaints. Additionally, only ±66% initiated treatments to understand these complaints, potentially influenced by the lack of prior academic exposure to biological rhythms as reported by ±76% of Brazilian psychologists interviewed. Importantly, ±15% did not believe in an association between mental health and biological rhythms, and even a significant ±67% were unfamiliar with the term chronobiology and ±63% were not able to describe any other biological rhythm except for the sleep-wake cycle. These results demonstrate that fundamental concepts in chronobiology and sleep science are unknown to a substantial proportion of Brazilian psychologists. In conclusion, we propose that this subject could be more effectively integrated into psychologists' academic training, potentially promoting benefits through the incorporation of a chronobiological approach in mental health practice.

Circadian rhythm disturbance and delirium in ICU patients: a prospective cohort study

BACKGROUND

Patients treated in the intensive care unit (ICU) may experience a reversal of day and night. The circadian rhythm in ICU patients can be disturbed.

METHODS

To explore the relationship between ICU delirium and the circadian rhythms of melatonin, cortisol and sleep. A prospective cohort study was carried out in a surgical ICU of a tertiary teaching hospital. Patients who were conscious during the ICU stay after surgery and were scheduled to stay in the ICU for more than 24 h were enrolled. Serum melatonin and plasma cortisol levels were measured three times a day by drawing arterial blood on the first three days after ICU admission. Daily sleep quality was assessed by the Richard-Campbell Sleep Questionnaire (RCSQ). The Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) was performed twice a day to screen for ICU delirium.

RESULTS

A total of 76 patients were included in this study, and 17 patients developed delirium during their ICU stay. Melatonin levels were different at 8:00 (p = 0.048) on day 1, at 3:00 (p = 0.002) and at 8:00 (p = 0.009) on day 2, and at all three time points on day 3 (p = 0.032, 0.014, 0.047) between delirium and non-delirium patients. The plasma cortisol level in the delirium patients was significantly lower than that in the non-delirium patients at 16:00 on day 1 (p = 0.025). The changes in melatonin and cortisol secretion levels exhibited obvious biological rhythmicity in non-delirium patients (p < 0.001 for melatonin, p = 0.026 for cortisol), while no rhythmicity was found in melatonin and cortisol secretion levels in the delirium group (p = 0.064 for melatonin, p = 0.454 for cortisol). There was no significant difference in RCSQ scores in the first three days between the two groups.

CONCLUSIONS

The disturbance of the circadian rhythm of melatonin and cortisol secretion was associated with the development of delirium in ICU patients. Clinical staff should pay more attention to the importance of maintaining patients' normal circadian rhythms in the ICU.

TRIAL REGISTRATION

The study was registered with the US National Institutes of Health ClinicalTrials.gov(NCT05342987) (25/04/2022).

Influence of Various Light Regimes on Morphofunctional Condition of Transplantable Melanoma B16

A study of the morphofunctional condition of mice with transplantable melanoma B16 under the influence of a normal daylight regime, constant lighting and constant darkness was conducted. It was shown that exposure to constant lighting leads to intensification of the proliferation of melanoma cells, more significant growth and spread of the tumor, the development of more pronounced secondary changes, the presence of perivascular growth and an increase in perineural invasion. At the same time, keeping of animals in constant darkness significantly reduced the intensity of the proliferative process in the tumor and lead to tumor regression in the absence of signs of lympho-, intravascular and intraneural invasion. Intergroup differences in tumor cell status were confirmed by the results of micromorphometric studies. It was also shown that the expression of clock genes was suppressed by an exposure to constant light, while an influence of constant darkness, on contrary, led to its intensification.

Data integration and analysis for circadian medicine

Data integration, data sharing, and standardized analyses are important enablers for data-driven medical research. Circadian medicine is an emerging field with a particularly high need for coordinated and systematic collaboration between researchers from different disciplines. Datasets in circadian medicine are multimodal, ranging from molecular circadian profiles and clinical parameters to physiological measurements and data obtained from (wearable) sensors or reported by patients. Uniquely, data spanning both the time dimension and the spatial dimension (across tissues) are needed to obtain a holistic view of the circadian system. The study of human rhythms in the context of circadian medicine has to confront the heterogeneity of clock properties within and across subjects and our inability to repeatedly obtain relevant biosamples from one subject. This requires informatics solutions for integrating and visualizing relevant data types at various temporal resolutions ranging from milliseconds and seconds to minutes and several hours. Associated challenges range from a lack of standards that can be used to represent all required data in a common interoperable form, to challenges related to data storage, to the need to perform transformations for integrated visualizations, and to privacy issues. The downstream analysis of circadian rhythms requires specialized approaches for the identification, characterization, and discrimination of rhythms. We conclude that circadian medicine research provides an ideal environment for developing innovative methods to address challenges related to the collection, integration, visualization, and analysis of multimodal multidimensional biomedical data.

Circadian rhythms of vital signs are associated with in-hospital mortality in critically ill patients: A retrospective observational study

Vital signs have been widely used to assess the disease severity of patients, but there is still a lack of research on their circadian rhythms. The objective is to explore the circadian rhythms of vital signs in critically ill patients and establish an in-hospital mortality prediction model. Study patients from the recorded eICU Collaborative Research Database were included in the present analyses. The circadian rhythms of vital signs are analyzed in critically ill patients using the cosinor method. Logistic regression was used to screen independent predictors and establish a prediction model for in-hospital mortality by multivariate logistic regression analysis and to show in the nomogram. Internal validation is used to evaluate the prediction model by bootstrapping with 1000 resamples. A total of 29,448 patients were included in the current analyses. The Mesor, Amplitude, and Peak time of vital signs, such as heart rate (HR), temperature, respiration rate (RR), pulse oximetry-derived oxygen saturation (SpO2), and blood pressure (BP), were significant differences between survivors and non-survivors . Logistic regression analysis showed that Mesor, Amplitude, and Peak time of HR, RR, and SpO2 were independent predictors for in-hospital mortality in critically ill patients. The area under the curve (AUC) and c-index of the prediction model for the Medical intensive care unit (MICU) and Surgical intensive care unit (SICU) were 0.807 and 0.801, respectively. The Hosmer-Lemeshow test P-values were 0.076 and 0.085, respectively, demonstrating a good fit for the prediction model. The calibration curve and decision curve analysis (DCA) also demonstrated its accuracy and applicability. Internal validation assesses the consistency of the results. There were significant differences in the circadian rhythms of vital signs between survivors and non-survivors in critically ill patients. The prediction model established by the Mesor, Amplitude, and Peak time of HR, RR, and SpO2 combined with the Acute Physiology and Chronic Health Evaluation (APACHE) IV score has good predictive performance for in-hospital mortality and may eventually support clinical decision-making.Abbreviations: ICU: Intensive care unit; MICU: Medical intensive care unit; SICU: Surgical intensive care unit; HR: Heart rate; RR: Respiration rate; SpO2: Pulse oximetry-derived oxygen saturation; BP: Blood pressure; SBP: Systolic blood pressure; DBP: Diastolic blood pressure; APACHE: Acute Physiology and Chronic Health Evaluation; bpm: beats per min; BMI: Body mass index; OR: Odd ratio; CI: Confidential interval; IQR: Interquartile range; SD: Standard deviation; ROC: Receiver operating characteristic; AUC: area under the curve; DCA: Decision curve analysis; IRB: Institutional review board.

Morphofunctional State and Circadian Rhythms of the Liver of Female Rats under the Influence of Chronic Alcohol Intoxication and Constant Lighting

A separate and combined effect of constant illumination and chronic alcohol intoxication (CAI) on diurnal dynamics of micromorphometric parameters of hepatocytes in female Wistar rats and p53, Ki-67, PER2, BMAL1, and ADH5 expression in these cells were studied. The increase in apoptotic activity and proliferation in all animals under the action of chronodestructors is shown. All experimental animals showed a decrease in BMAL1 expression and increase in PER2 expression; ADH5 is overexpressed under the influence of ethanol. Circadian rhythms (CRs) of BMAL1, PER2, p53, and Ki-67 expression persist in all groups, except combined action of chronodestructors, and ADH5 CRs persist in all groups—thus, these rhythms in females are quite stable. CRs of the hepatocyte nuclei area are preserved in all the studied groups, although they undergo a significant shift. At the same time, the CRs of the hepatocyte area are destroyed under the action of light, both independently and in combination with CAI, and the CR of the nuclear-cytoplasmic ratio (NCR) is destroyed by exposure to CAI. It can be assumed that CRs of the hepatocyte area are significantly affected by dark deprivation and NCR rhythm is sensitive to ethanol consumption, while the stability of studied genes’ expression rhythms at separate influences of studied chronodestructors is maintained by yet unknown adaptation mechanisms. It is necessary to note that, according to our previous studies of male rats, rat females show significantly greater stability of the studied CRs.

Desynchronosis: Types, Main Mechanisms, Role in the Pathogenesis of Epilepsy and Other Diseases: A Literature Review

Circadian information is stored in mammalian tissues by an autonomous network of transcriptional feedback loops that have evolved to optimally regulate tissue-specific functions. Currently, stable circadian rhythms of the expression of clock genes (Bmal1/Per2/Cry1, etc.), hormones, and metabolic genes (Glut4/leptin, etc.) have been demonstrated. Desynchronoses are disorders of the body’s biorhythms, where the direction and degree of shift of various indicators of the oscillatory process are disturbed. Desynchronosis can be caused by natural conditions or man-made causes. The disruption of circadian rhythms is a risk factor for the appearance of physiological and behavioral disorders and the development of diseases, including epilepsy, and metabolic and oncological diseases. Evidence suggests that seizure activity in the epilepsy phenotype is associated with circadian dysfunction. Interactions between epilepsy and circadian rhythms may be mediated through melatonin, sleep–wake cycles, and clock genes. The correction of circadian dysfunction can lead to a decrease in seizure activity and vice versa. Currently, attempts are being made to pharmacologically correct desynchronosis and related psycho-emotional disorders, as well as combined somatic pathology. On the other hand, the normalization of the light regimen, the regulation of sleep–wake times, and phototherapy as additions to standard treatment can speed up the recovery of patients with various diseases.

Three-Minute Diagnostic Assessment for Delirium using the Confusion Assessment Method (3D-CAM): French translation and cultural adaptation

PURPOSE

The routine use of validated diagnostic instruments is key to identifying delirious patients early and expediting care. The 3-Minute Diagnostic Assessment for Delirium using the Confusion Assessment Method (3D-CAM) instrument is a brief, easy to use, sensitive, and specific delirium assessment tool for hospitalized patients. We aimed to translate the original English version into French, and then adapt it to older high-risk patients.

METHODS

Translation and adaptation of the questionnaire were guided by an expert committee and the 3D-CAM instrument developer. During the translation phase, we achieved semantic and conceptual equivalence of the instrument by conducting forward and backward translations. During the adaptation phase, we assessed the face validity, clarity of wording, and ease of use of the translated questionnaire by administering it to 30 patients and their caregivers in peri-interventional and medical intermediate care units. During both phases, we used qualitative (goal and adequacy of the questionnaire) and quantitative (Sperber score, clarity score) criteria.

RESULTS

Translation: four items were judged inadequate and were revised until all reached a Sperber score of < 3/7. Face validity: 91% of patients thought the questionnaire was designed to assess memory, thoughts, or reasoning. Clarity: eight items required adjustments until all scored ≥ 9/10 for clarity. Ease of use: all bedside caregivers reported that the questionnaire was easy to complete after receiving brief instructions.

CONCLUSIONS

We produced a culturally adapted French version of the 3D-CAM instrument that is well understood and well-received by older high-risk patients and their caregivers.

Daily patterns in parasite processes: diel variation in fish louse transcriptomes

Parasites, similar to all other organisms, time themselves to environmental cues using a molecular clock to generate and maintain rhythms. Chronotherapeutic (timed treatment) techniques based on such rhythms offer great potential for improving control of chronic, problematic parasites. Fish lice are a key disease threat in aquaculture, with current control insufficient. Assessing the rhythmicity of fish lice transcriptomes offers not only insight into the viability of chronotherapy, but the opportunity to identify new drug targets. Here, for the first known time in any crustacean parasite, diel changes in gene transcription are examined, revealing that approximately half of the Argulus foliaceus annotated transcriptome displays significant daily rhythmicity. We identified rhythmically transcribed putative clock genes including core clock/cycle and period/timeless pairs, alongside rhythms in feeding-associated genes and processes involving immune response, as well as fish louse drug targets. A substantial number of gene pathways showed peak transcription in hours immediately preceding onset of light, potentially in anticipation of peak host anti-parasite responses or in preparation for increased feeding activity. Genes related to immune haemocyte activity and chitin development were more highly transcribed 4 h post light onset, although inflammatory gene transcription was highest during dark periods. Our study provides an important resource for application of chronotherapy in fish lice; timed application could increase efficacy and/or reduce dose requirement, improving the current landscape of drug resistance and fish health while reducing the economic cost of infection.

Association of Poor Sleep Burden in Middle Age and Older Adults With Risk for Delirium During Hospitalization

BACKGROUND

Delirium is a distressing neurocognitive disorder recently linked to sleep disturbances. However, the longitudinal relationship between sleep and delirium remains unclear. This study assessed the associations of poor sleep burden, and its trajectory, with delirium risk during hospitalization.

METHODS

About 321 818 participants from the UK Biobank (mean age 58 ± 8 years [SD]; range 37-74 years) reported (2006-2010) sleep traits (sleep duration, excessive daytime sleepiness, insomnia-type complaints, napping, and chronotype-a closely related circadian measure for sleep timing), aggregated into a sleep burden score (0-9). New-onset delirium (n = 4 775) was obtained from hospitalization records during a 12-year median follow-up. About 42 291 (mean age 64 ± 8 years; range 44-83 years) had repeat sleep assessment on average 8 years after their first.

RESULTS

In the baseline cohort, Cox proportional hazards models showed that moderate (aggregate scores = 4-5) and severe (scores = 6-9) poor sleep burden groups were 18% (hazard ratio = 1.18 [95% confidence interval: 1.08-1.28], p < .001) and 57% (1.57 [1.38-1.80], p < .001), more likely to develop delirium, respectively. The latter risk magnitude is equivalent to 2 additional cardiovascular risks. These findings appeared robust when restricted to postoperative delirium and after exclusion of underlying dementia. Higher sleep burden was also associated with delirium in the follow-up cohort. Worsening sleep burden (score increase ≥2 vs no change) further increased the risk for delirium (1.79 [1.23-2.62], p = .002) independent of their baseline sleep score and time lag. The risk was highest in those younger than 65 years at baseline (p for interaction <.001).

CONCLUSION

Poor sleep burden and worsening trajectory were associated with increased risk for delirium; promotion of sleep health may be important for those at higher risk.

Chronodisruption and Ambulatory Circadian Monitoring in Cancer Patients: Beyond the Body Clock

Purpose of Review

Circadian rhythms impose daily rhythms a remarkable variety of metabolic and physiological functions, such as cell proliferation, inflammation, and DNA damage response. Accumulating epidemiological and genetic evidence indicates that circadian rhythms’ disruption may be linked to cancer. The integration of circadian biology into cancer research may offer new options for increasing cancer treatment effectiveness and would encompass the prevention, diagnosis, and treatment of this disease.

Recent Findings

In recent years, there has been a significant development and use of multi-modal sensors to monitor physical activity, sleep, and circadian rhythms, allowing, for the very first time, scaling accurate sleep monitoring to epidemiological research linking sleep patterns to disease, and wellness applications providing new potential applications.

Summary

This review highlights the role of circadian clock in tumorigenesis, cancer hallmarks and introduces the state-of-the-art in sleep-monitoring technologies, discussing the eventual application of insights in clinical settings and cancer research.

Temperature Profile and Adverse Outcomes After Discharge From the Intensive Care Unit

BACKGROUND

A predictive model that uses the rhythmicity of core body temperature (CBT) could be an easily accessible clinical tool to ultimately improve outcomes among critically ill patients.

OBJECTIVES

To assess the relation between the 24-hour CBT profile (CBT-24) before intensive care unit (ICU) discharge and clinical events in the step-down unit within 7 days of ICU discharge.

METHODS

This retrospective cohort study in a tertiary ICU at a single center included adult patients requiring acute invasive ventilation for more than 48 hours and assessed major clinical adverse events (MCAEs) and rapid response system activations (RRSAs) within 7 days of ICU discharge (MCAE-7 and RRSA-7, respectively).

RESULTS

The 291 enrolled patients had a median mechanical ventilation duration of 139 hours (IQR, 50-862 hours) and at admission had a median Acute Physiology and Chronic Health Evaluation II score of 22 (IQR, 7-42). At least 1 MCAE or RRSA occurred in 64% and 22% of patients, respectively. Independent predictors of an MCAE-7 were absence of CBT-24 rhythmicity (odds ratio, 1.78 [95% CI, 1.07-2.98]; P = .03), Sequential Organ Failure Assessment score at ICU discharge (1.10 [1.00-1.21]; P = .05), male sex (1.72 [1.04-2.86]; P = .04), age (1.02 [1.00-1.04]; P = .02), and Charlson Comorbidity Index (0.87 [0.76-0.99]; P = .03). Age (1.03 [1.01-1.05]; P = .006), sepsis at ICU admission (2.02 [1.13-3.63]; P = .02), and Charlson Comorbidity Index (1.18 [1.02-1.36]; P = .02) were independent predictors of an RRSA-7.

CONCLUSIONS

Use of CBT-24 rhythmicity can assist in stratifying a patient's risk of subsequent deterioration during general care within 7 days of ICU discharge.

Anterior Pituitary Hormones in Blood and Cerebrospinal Fluid of Patients in Neurocritical Care

Background: Anterior pituitary hormones in blood follow a circadian rhythm, which may be influenced by various factors such as intracranial pathologies. In cerebrospinal fluid (CSF), pituitary hormones have been collected only selectively and circadian rhythm has not yet been investigated. This pilot study analysed diurnal variations of anterior pituitary hormones in patients in neurocritical care to determine whether circadian rhythmicity exists in these patients. Possible influences of intracranial pathologies were also investigated. Blood and CSF concentrations were assessed simultaneously to explore the value of blood concentrations as a surrogate parameter for CSF levels. Methods: Blood and CSF samples of 20 non-sedated patients were collected at 06:00, noon, 18:00 and midnight, and analysed for adrenocorticotropic hormone (ACTH), cortisol, thyroid-stimulating hormone (TSH) and insulin-like growth factor-1 (IGF-1) concentrations at each of the four time points. ACTH and IGF-1 were measured by sandwich chemiluminescence immunoassay. Cortisol and TSH were measured by electrochemiluminescence immunoassay. Results: Results showed inconsistent circadian rhythms. Less than 50% of the patients showed a circadian rhythmicity of ACTH, cortisol, TSH or IGF-1. Significance of diurnal variations was only present for blood concentrations of TSH. Correlations between blood and CSF concentrations were strong for cortisol and TSH. Conclusions: CSF concentrations were only in the measurable range in some of the patients. No clear circadian rhythmicity could be identified, except for TSH in blood. Absence of significant diurnal variations could be explained by the underlying pathologies or disturbing influences of the intensive care unit. Blood concentrations of cortisol and TSH may be suitable surrogate parameters for CSF.

Sleep, Pain, and Cognition: Modifiable Targets for Optimal Perioperative Brain Health

The prevention of perioperative neurocognitive disorders is a priority for patients, families, clinicians, and researchers. Given the multiple risk factors present throughout the perioperative period, a multicomponent preventative approach may be most effective. The objectives of this narrative review are to highlight the importance of sleep, pain, and cognition on the risk of perioperative neurocognitive disorders and to discuss the evidence behind interventions targeting these modifiable risk factors. Sleep disruption is associated with postoperative delirium, but the benefit of sleep-related interventions is uncertain. Pain is a risk factor for postoperative delirium, but its impact on other postoperative neurocognitive disorders is unknown. Multimodal analgesia and opioid avoidance are emerging as best practices, but data supporting their efficacy to prevent delirium are limited. Poor preoperative cognitive function is a strong predictor of postoperative neurocognitive disorder, and work is ongoing to determine whether it can be modified to prevent perioperative neurocognitive disorders.

Morphofunctional State and Circadian Rhythms of the Liver under the Influence of Chronic Alcohol Intoxication and Constant Lighting

A study of the influence of chronic alcohol intoxication, constant illumination and their combined effects on the morphofunctional state of the rat liver and the circadian rhythms (CR) of the studied parameters of the organism was carried out. It was found that both alcohol and constant illumination caused significant changes in the structure of the liver, as well as in the circadian rhythmicity of micromorphometric parameters of hepatocytes, ALT, and total and direct bilirubin rhythms; however, the combined effects of ethanol and constant illumination had the most significant effect on the studied parameters of the organism. These two factors caused disturbances in the circadian rhythms of the micromorphometric parameters of hepatocytes, disruption of the circadian rhythms of total protein, albumin, AST, ALT, and direct and total bilirubin, as well as disturbances in the expression and rhythmicity of the studied clock genes against a background of the development of an inflammatory process in the liver.

Daytime variation in SARS-CoV-2 infection and cytokine production

S. Ray and A. Reddy recently anticipated the implication of circadian rhythm in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the causative agent of the coronavirus disease (Covid-19). In addition to its key role in the regulation of biological functions, the circadian rhythm has been suggested as a regulator of viral infections. Specifically, the time of day of infection was found critical for illness progression, as has been reported for influenza, respiratory syncytial and parainfluenza type 3 viruses. We analyzed circadian rhythm implication in SARS-CoV-2 virus infection of isolated human monocytes, key actor cells in Covid-19 disease, from healthy subjects. The circadian gene expression of BMAL1 and CLOCK genes was investigated with q-RTPCR. Monocytes were infected with SARS-CoV-2 virus strain and viral infection was investigated by One-Step qRT-PCR and immunofluorescence. Interleukin (IL)-6, IL-1β and IL-10 levels were also measured in supernatants of infected monocytes. Using Cosinor analysis, we showed that BMAL1 and CLOCK transcripts exhibited circadian rhythm in monocytes with an acrophase and a bathyphase at Circadian Time (CT)6 and CT17. After 48 h, the amount of SARS-CoV-2 virus increased in the monocyte infected at CT6 compared to CT17. The high virus amount at CT6 was associated with significant increased release in IL-6, IL-1β and IL-10 compared to CT17. Our results suggest that time day of SARS-CoV-2 infection affects viral infection and host immune response. They support consideration of circadian rhythm in SARS-CoV-2 disease progression and we propose circadian rhythm as a novel target for managing viral progression.

The clock diet: a practical nutritional guide to manage obesity through chrononutrition

Chronobiology studies the biological rhythms or circadian cycles of living organisms and their adaptation to external changes. Biological rhythms can affect hormone production cycles such as sleep/wake, and nutrition/fasting, but these factors can also alter the circadian rhythm (CR). In recent years, numerous studies have highlighted how feeding times and frequency can influence biological rhythms. Additionally, individuals' chronotype, working shifts, and food intake can make a deep impact on people's tendency to develop obesity and metabolic diseases. In this context, a single food and a specific combination of these, can also affect the CR and fasting cycle and consequently body weight and viceversa. The purpose of the review is to propose practical nutritional recommendations to help in resynchronizing the circadian rhythm as a tool in weight control.

Day-to-day progression of vital-sign circadian rhythms in the intensive care unit

Background

Disrupted vital-sign circadian rhythms in the intensive care unit (ICU) are associated with complications such as immune system disruption, delirium and increased patient mortality. However, the prevalence and extent of this disruption is not well understood. Tools for its detection are currently limited.

Methods

This paper evaluated and compared vital-sign circadian rhythms in systolic blood pressure, heart rate, respiratory rate and temperature. Comparisons were made between the cohort of patients who recovered from the ICU and those who did not, across three large, publicly available clinical databases. This comparison included a qualitative assessment of rhythm profiles, as well as quantitative metrics such as peak–nadir excursions and correlation to a demographically matched ‘recovered’ profile.

Results

Circadian rhythms were present at the cohort level in all vital signs throughout an ICU stay. Peak–nadir excursions and correlation to a ‘recovered’ profile were typically greater throughout an ICU stay in the cohort of patients who recovered, compared to the cohort of patients who did not.

Conclusions

These results suggest that vital-sign circadian rhythms are typically present at the cohort level throughout an ICU stay and that quantitative assessment of these rhythms may provide information of prognostic use in the ICU.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03574-w.

The Impact of Earplugs and Eye Masks on Sleep Quality in Surgical ICU Patients at Risk for Frequent Awakenings

OBJECTIVES

Sleep disturbances may contribute to the development of delirium, prolonged ICU stay, and increased mortality. There is conflicting data on the effectiveness of earplugs and eye masks for sleep promotion in the ICU. This study evaluates the impact of earplugs and eye masks on sleep quality in postoperative surgical ICU patients at risk for frequent awakenings.

DESIGN

Prospective randomized controlled trial.

SETTING

Surgical ICU within the University of Texas Southwestern Medical Center.

PATIENTS

Adult, female patients admitted to the surgical ICU requiring hourly postoperative assessments following breast free flap surgery between February 2018 and October 2019.

INTERVENTIONS

Patients were randomized into an intervention group or a control group. The intervention group received earplugs and eye masks in addition to standard postoperative care, whereas the control group received standard postoperative care.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was overall sleep quality assessed via the Richards-Campbell Sleep Questionnaire. Secondary outcomes of patient satisfaction and rates of ICU delirium were assessed with a modified version of the Family Satisfaction in the ICU survey and the Confusion Assessment Method for the ICU. After a planned interim analysis, the study was stopped early because prespecified criteria for significance were attained. Compared with the control group's average Richards-Campbell Sleep Questionnaire total score of 47.3 (95% CI, 40.8-53.8), the intervention group's average Richards-Campbell Sleep Questionnaire total score was significantly higher at 64.5 (95% CI, 58.3-70.7; p = 0.0007). There were no significant between-group differences for Confusion Assessment Method for the ICU scores or modified Family Satisfaction in the ICU survey scores.

CONCLUSIONS

These results suggest that earplugs and eye masks are effective in improving sleep quality in ICU patients undergoing frequent assessments. The results strengthen the evidence for nonpharmacologic sleep-promoting adjuncts in the ICU.

Circadian rhythm in critically ill patients: Insights from the eICU Database

Objective

To investigate the circadian variation among critically ill patients and its association with clinical characteristics and survival to hospital discharge in a large population of patients in the intensive care unit (ICU).

Methods

Circadian variation was analyzed by fitting cosinor models to hourly blood pressure (BP) measurements in patients of the eICU Collaborative Research Database with an ICU length of stay of at least 3 days. We calculated the amplitude of the 24-hour circadian rhythm and time of the day when BP peaked. We determined the association between amplitude and time of peak BP and severity of illness, medications, mechanical intubation, and survival to hospital discharge.

Results

Among 23,355 patients (mean age 65 years, 55% male), the mean amplitude of the 24-hour rhythm was 4.5 ± 3.1 mm Hg. Higher APACHE-IV scores, sepsis, organ dysfunction, and mechanical ventilation were associated with a lower amplitude and a shifted circadian rhythm (P < .05 for all). The timing of the BP peak was associated with in-hospital mortality (P < .001). Higher BP amplitude was associated with shorter ICU (2 mm Hg amplitude: 7.0 days, 8 mm Hg amplitude: 6.7 days) and hospital (2 mm Hg amplitude: 11.8 days, 8 mm Hg amplitude: 11.3 days) lengths of stay and lower in-hospital mortality (2 mm Hg amplitude: 18.2%, 8 mm Hg amplitude: 15.2%) (P < .001 for all).

Conclusion

The 24-hour rhythm is dampened and phase-shifted in sicker patients and those on mechanical ventilation, vasopressors, or inotropes. Dampening and phase shifting are associated with a longer length of stay and higher in-hospital mortality.

Circadian rhythm as a therapeutic target

The circadian clock evolved in diverse organisms to integrate external environmental changes and internal physiology. The clock endows the host with temporal precision and robust adaptation to the surrounding environment. When circadian rhythms are perturbed or misaligned, as a result of jet lag, shiftwork or other lifestyle factors, adverse health consequences arise, and the risks of diseases such as cancer, cardiovascular diseases or metabolic disorders increase. Although the negative impact of circadian rhythm disruption is now well established, it remains underappreciated how to take advantage of biological timing, or correct it, for health benefits. In this Review, we provide an updated account of the circadian system and highlight several key disease areas with altered circadian signalling. We discuss environmental and lifestyle modifications of circadian rhythm and clock-based therapeutic strategies, including chronotherapy, in which dosing time is deliberately optimized for maximum therapeutic index, and pharmacological agents that target core clock components and proximal regulators. Promising progress in research, disease models and clinical applications should encourage a concerted effort towards a new era of circadian medicine.

The efficacy of nursing interventions on sleep quality in hospitalized patients: A systematic review of randomized controlled trials

OBJECTIVE

To determine the effect of interventions that could be performed by nurses to improve the sleep quality of hospitalized patients in acute and semi-acute units.

DESIGN

A systematic review of randomized controlled trials and narrative synthesis.

DATA SOURCES

Seven electronic databases (PubMed, CINAHL Plus, Scopus, ISI WoS, CENTRAL, PsycInfo, and Embase) were accessed on 20 May 2019 with a temporal limit of 10 years prior.

REVIEW METHODS

Original research studies of interventions that could be delivered by nurses to improve sleep quality during hospitalization in acute and semi-acute units were included. Study selection, data extraction, and risk of bias assessment were performed by two independent reviewers.

RESULTS

Seventeen studies met the inclusion criteria and were included in this review. The interventions carried out in the trials were classified into four categories of measurement: environmental, physical, behavioural, and combined. Fourteen studies obtained statistically significant improvements; two showed a blend of significant and non-significant improvements; and one reported non-significant results. However, only four trials of the seventeen were judged as having a low risk of bias.

CONCLUSIONS

Overall evidence about interventions that could be performed by nurses to improve perceived sleep quality in hospitalized patients was found to be positive, and no negative effects were reported. However, higher quality research using both subjective and objective measures is needed, in order to strengthen the evidence.

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

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

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

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

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

Improving Sleep in Intensive Care Unit: An Overview of Diagnostic and Therapeutic Options

Good quality sleep is considered to be essential for healthy living and recovering from illness. It would be logical to think that good quality sleep is most required when a patient is critically ill in an intensive care unit (ICU). Several studies have demonstrated poor quality of sleep while the patients are in ICU. Subjective tools such as questionnaires while simple are unreliable to accurately assess sleep quality. Relatively few studies have used standardized polysomnography. The use of novel biological markers of sleep such as serum brain-derived neurotrophic factor concentrations may help in conjunction with polysomnography to assess sleep quality in critically ill patients. Attempts to improve sleep included nonpharmacological interventions including the use of earplugs, eye sleep masks, and pharmacological agents including ketamine, propofol, dexmedetomidine, and benzodiazepines. The evidence for these interventions remains unclear. Further research is needed to assess quality of sleep and improve the sleep quality in intensive care settings.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A novel time-dimension and circadian rhythm-dependent strategy for pharmacodynamic evaluation of Uncaria in the regulation of neurotransmitter circadian metabolic homeostasis in spontaneously hypertensive rats

In the present study, we aimed to use metabolomics platforms to examine circadian-regulated neurotransmitters across a 24-h day and the effects of Uncaria administration on daily rhythmicity in order to establish a strategy for evaluating the spatiotemporal efficacy evaluation strategy of Uncaria. By using targeted ultrahigh performance liquid chromatography-mass spectrometry metabolomics, we quantified 32 neurotransmitter metabolites every 4 h over 24 h. To assess 24-h metabolite rhythmicity, we performed cosinor analysis. The expression of hypothalamic rhythm genes was detected by reverse transcription polymerase chain reaction (RT-PCR). Data revealed circadian loss of many neurotransmitters during the entire circadian cycle in the serum of group M, indicating that hypertension causes circadian rhythm disorders. Cosinor analysis of the rhythmic oscillations of the levels of 32 neurotransmitters in the three groups showed that the metabolite rhythms peaked at approximately the same time of day (ZT4 and ZT16). Moreover, the amplitudes of the metabolite rhythms were altered. After treatment with Uncaria, the amplitudes of 13 neurotransmitters reverted to normal. The change trends in the hypothalamic rhythm genes confirmed the rhythm changes in neurotransmitters. Collectively, a novel pharmacodynamic evaluation strategy was established to dynamically observe the holistic effects of Uncaria on 32 circulating neurotransmitters within 24 h from the perspective of time dimension.

For Whom the Clock Ticks: Clinical Chronobiology for Infectious Diseases

The host defense against pathogens varies among individuals. Among the factors influencing host response, those associated with circadian disruptions are emerging. These latter depend on molecular clocks, which control the two partners of host defense: microbes and immune system. There is some evidence that infections are closely related to circadian rhythms in terms of susceptibility, clinical presentation and severity. In this review, we overview what is known about circadian rhythms in infectious diseases and update the knowledge about circadian rhythms in immune system, pathogens and vectors. This heuristic approach opens a new fascinating field of time-based personalized treatment of infected patients.

Preoperative circadian physical activity rhythm and postoperative delirium in cardiovascular surgery patients

Postoperative delirium, a common perioperative complication, is frequently observed in elderly surgical patients. Few studies have investigated the life rhythm of preoperative patients, and whether or not the preoperative life rhythm is associated with the development of postoperative delirium. The purpose of this study was to investigate the relationship between the preoperative circadian physical activity rhythm and postoperative delirium in cardiovascular surgery patients. A total of 43 patients who underwent cardiovascular surgery were included in this prospective study between July 2016 and September 2017 at Kobe University Hospital. All subjects used a "Life Microscope" wristband (a wristwatch-type terminal incorporating a 3-axis accelerometer monitoring) for 3-7 days at home before the planned surgery. Hourly mean values were calculated for the metabolic equivalents from the obtained activity amounts, and subsequently evaluated using cosine periodic regression analysis. The circadian rhythm parameters of mesor (24 h time series mean), amplitude (half the peak-trough variation), and acrophase (peak time) for the metabolic equivalents were obtained. The intensive care delirium screening checklist was used to assess for postoperative delirium. The acrophase significantly advanced in the postoperative delirium group (median, 11:55 h [interquartile range, 11:06-12:27 h]) compared to the group without postoperative delirium (median, 13:25 h [interquartile range, 12:52-14:13 h]) (p < .001). Furthermore, binary logistic regression analysis showed that advances in the physical activity phase remained independently associated with postoperative delirium (odds ratio, 0.003 [95% confidence interval, 0-0.63]). These results suggest that misalignment between advanced life rhythm before hospitalization and life rhythm after hospitalization might be associated with risk for developing postoperative delirium. Our results led us to speculate that adequate consideration of the patient's life rhythm before hospitalization is needed to prevent postoperative delirium.

Restoring circadian synchrony in vitro facilitates physiological responses to environmental chemicals

BACKGROUND

The growing requirement of hazard and risk assessment of environmental chemicals and the efforts to minimize animal testing, increases the demand for innovative and predictive in vitro test systems in toxicology, reflecting the physiological conditions of human nature. Here, an elemental factor regulating a variety of physiological processes is the day-night rhythm. This circadian rhythm, describing a biological oscillation with a 24-h period is hardly acknowledged in toxicology and test method development. Whilst, in animals or humans the entire organism exhibits a rigorous cellular circadian synchrony, in conventional in vitro systems each cell follows its own rhythm, due to the absence of appropriate synchronizing signals.

OBJECTIVE

Here we investigated whether circadian synchronization of human cells in an in vitro system improves the cellular response and, thus, increases the sensitivity of the test system. Since the circadian regulation of metabolism is particularly well understood, and dioxin and dioxin-like compounds are of major concern for environmental health we focused on the ubiquitous drug metabolizing detoxification system mediated by the aryl hydrocarbon receptor (AHR).

METHODS

To this end, we applied various prototypical AHR activators onto different human cell lines under non-synchronized or circadian synchronized conditions and determined the dose response on representative endogenous target genes.

RESULTS

Remarkably, the cellular response dynamic upon chemical treatment was substantially enhanced in circadian synchronized cells and followed a rhythmic expression pattern. This broader dynamic range was associated with a strikingly higher induction of AHR target genes and the corresponding enzymatic activity, thereby rather mimicking the in vivo situation.

CONCLUSION

Our findings indicate that a synchronized circadian rhythm in a cell culture based test system can improve the physiological relevance of an appropriate in vitro method by reflecting the biological in vivo situation more closely. Accordingly, it is a promising tool to facilitate the wide acceptance of in vitro methods in the field of regulatory toxicology and to further optimize the toxicological assessment of environmental chemicals.

Prognostic value of circulating lymphocyte B and plasma immunoglobulin M on septic shock and sepsis: a systematic review and meta-analysis

OBJECTIVE

Normal B lymphocyte function and antibody secretion during inflammation can provide critical protection for the host. We aimed to synthesize existing evidence to explore whether circulating B cells and plasma immunoglobulin M (IgM) levels were associated with survival during sepsis.

METHODS

PubMed, Embase, ISI Web of Knowledge, Cochrane Central Register of Controlled Trials were systematically searched. Studies with data on circulating B cells and plasma IgM levels within the initial 24 hours after sepsis onset were selected.

RESULTS

A total of 11 studies were qualified for inclusion in this systematic review and meta-analysis with a total of 829 patients with sepsis and/or septic shock. Number of circulating B cells was similar between septic patients and health controls (SMD = -1.81, 95% CI: -4.15, 0.54; P = 0.13, I² = 99%), while it was significantly reduced in sepsis survivors versus sepsis non-survivors (SMD = -0.60, 95% CI: -0.87, -0.32; P < 0.0001, I² = 0%). Concentration of plasma IgM level was significantly decreased in septic patients as compared with healthy controls. Also, the plasma IgM level was significantly lower in sepsis survivors versus sepsis non-survivors.

CONCLUSIONS

A poor prognostic survival outcome was observed for patients with decreased circulating B cells as well as IgM levels within the initial 24 h after sepsis onset.

Absence of a diurnal rhythm of oxytocin and arginine-vasopressin in human cerebrospinal fluid, blood and saliva

PURPOSE

The aims of our study were to determine first circadian influences on central concentrations of the neuropeptides oxytocin and arginine-vasopressin and second to investigate if these central concentrations are associated with those in the peripheral compartments blood and saliva in neurocritical care patients. We therefore included patients with external ventricular drain who attended a neurosurgical intensive care unit and were not exposed to painful or stressful stimuli during the sampling period. For this purpose, blood, cerebrospinal fluid and saliva were collected in a 24-hour-interval at the timepoints 06:00, 12:00, 18:00 and 24:00.

RESULTS

In none of the three body fluids examined, significant time-dependent fluctuations of oxytocin and arginine-vasopressin concentrations could be detected during the 24-hour sampling period. The only exception was the subgroup of postmenopausal women whose oxytocin concentrations in cerebrospinal fluid at 12:00 were significantly higher than at 18:00. Correlations of blood and cerebrospinal fluid and blood and saliva neuropeptide levels were very weak to weak at each timepoint. Cerebrospinal fluid and saliva oxytocin levels showed a moderate correlation at 06:00 but did correlate very weak at the other timepoints.

CONCLUSIONS

Central as well as peripheral oxytocin and arginine-vasopressin concentrations in neurocritical care patients did not show significant diurnal fluctuations. No strong correlations between central and peripheral neuropeptide concentrations could be detected under basal conditions. If investigators even though decide to use saliva concentrations as surrogate parameter for central neuropeptide activity, they have to consider that correlations of cerebrospinal fluid and saliva oxytocin seem to be highest in the early morning.

A large-scale study reveals 24-h operational rhythms in hospital treatment

We found that orders and initial doses of treatment in the hospital were strongly influenced by time of day, regardless of drug type, diagnosis, or care unit. As the first large-scale account of 24-h rhythms in hospital medicine, this study identifies a potential operational barrier to best clinical care. Clinical decisions should be made around the clock; pain, infection, hypertensive crisis, and other conditions do not occur selectively in the morning. Systemic bias in the timing of medicine may also conflict with circadian biology, which can influence when certain treatments are most effective or safe. Our findings suggest that time of day in hospital operations deserves further consideration.

Hospitals operate 24 h a day, and it is assumed that important clinical decisions occur continuously around the clock. However, many aspects of hospital operation occur at specific times of day, including medical team rounding and shift changes. It is unclear whether this impacts patient care, as no studies have addressed this. We analyzed the daily distribution of ∼500,000 doses of 12 separate drugs in 1,546 inpatients at a major children’s hospital in the United States from 2010 to 2017. We tracked both order time (when a care provider places an electronic request for a drug) and dosing time (when the patient receives the drug). Order times were time-of-day−dependent, marked by distinct morning-time surges and overnight lulls. Nearly one-third of all 103,847 orders for treatment were placed between 8:00 AM and 12:00 PM. First doses from each order were also rhythmic but shifted by 2 h. These 24-h rhythms in orders and first doses were remarkably consistent across drugs, diagnosis, and hospital units. This rhythm in hospital medicine coincided with medical team rounding time, not necessarily immediate medical need. Lastly, we show that the clinical response to hydralazine, an acute antihypertensive, is dosing time-dependent and greatest at night, when the fewest doses were administered. The prevailing dogma is that hospital treatment is administered as needed regardless of time of day. Our findings challenge this notion and reveal a potential operational barrier to best clinical care.

Better Sleep Experience for the Critically Ill: A Comprehensive Strategy for Designing Hospital Soundscapes

In this paper, the sleep phenomenon is considered in relation to critical care soundscapes with the intention to inform hospital management, medical device producers and policy makers regarding the complexity of the issue and possible modes of design interventions. We propose a comprehensive strategy based on soundscape design approach that facilitates a systematic way of tackling the auditory quality of critical care settings in favor of better patient sleep experience. Future research directions are presented to tackle the knowledge deficits in designing for critical care soundscapes that cater for patient sleep. The need for scientifically-informed design interventions for improving patient sleep experience in critical care is highlighted. The value of the soundscape design approach for resolving other sound-induced problems in critical care and how the approach allows for patient-centred innovation that is beyond the immediate sound issue are further discussed.

The Pulse-Respiration Quotient: A Powerful but Untapped Parameter for Modern Studies About Human Physiology and Pathophysiology

A specific and unique aspect of cardiorespiratory activity can be captured by dividing the heart rate (HR) by the respiration rate (RR), giving the pulse-respiration quotient (PRQ = HR/RR). In this review article, we summarize the main findings of studies using and investigating the PRQ. We describe why the PRQ is a powerful parameter that captures complex regulatory states of the cardiorespiratory system, and we highlight the need to re-introduce the use of this parameter into modern studies about human physiology and pathophysiology. In particular, we show that the PRQ (i) changes during human development, (ii) is time-dependent (ultradian, circadian, and infradian rhythms), (iii) shows specific patterns during sleep, (iv) changes with physical activity and body posture, (v) is linked with psychophysical and cognitive activity, (vi) is sex-dependent, and (vii) is determined by the individual physiological constitution. Furthermore, we discuss the medical aspects of the PRQ in terms of applications for disease classification and monitoring. Finally, we explain why there should be a revival in the use of the PRQ for basic research about human physiology and for applications in medicine, and we give recommendations for the use of the PRQ in studies and medical applications.

Novel Vasopressors in the Treatment of Vasodilatory Shock: A Systematic Review of Angiotensin II, Selepressin, and Terlipressin

Study Objective:

Vasodilatory shock is the most common type of shock. Catecholamine vasopressors are the cornerstone of hemodynamic therapy but carry risks. Angiotensin II (AT2) was recently approved, and other novel agents (selepressin and terlipressin) are under investigation and used outside the United States (terlipressin). We performed a systematic review to summarize the efficacy and safety of these novel vasopressors and to offer guidance on their appropriate use.

Design:

Systematic review of controlled trials.

Methods:

Numerous databases were searched using terms related to angiotensin II, selepressin, terlipressin, vasopressor, and shock. Twenty-one citations, including 16 prospective comparative trials and 5 post hoc analyses reporting effects of AT2, selepressin, and terlipressin, were reviewed for data on outcomes related to hemodynamic measures, mortality, severity and duration of illness, concomitant vasopressor utilization, and adverse effects. Findings from eligible literature are described qualitatively using Cochrane methods.

Results:

Fourteen controlled trials were assessed after exclusion of 2 dated trials of a distinct AT2 formulation. Trials are limited for AT2 (n = 2) and selepressin (n = 1), while terlipressin was investigated in 11 small trials. Overall, the trials have an unclear risk of bias. Most report mean arterial pressure (MAP) as primary end point, and all indicate novel vasopressors increase MAP compared to placebo and to a similar degree as with catecholamine vasopressors. Mortality findings are preliminary, as they have been limited to specific subgroups in trials of terlipressin and post hoc analyses of one trial of AT2. Trials reported safety concerns for each agent including thromboembolism with AT2 and ischemia with terlipressin/selepressin.

Conclusion:

In this systematic review, controlled trials of novel vasopressors in treatment of vasodilatory shock were limited and of low quality. Angiotensin II, selepressin, and terlipressin appear to significantly increase MAP, but further study is required, particularly for selepressin, to determine their safety, efficacy, and role in treatment of vasodilatory shock.

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

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