Delirium: a disturbance of circadian integrity?

Efficacy and safety of perioperative melatonin for postoperative delirium in patients undergoing surgery: a systematic review and meta-analysis

OBJECTIVE

To assess the efficacy and safety of perioperative melatonin and melatonin agonists in preventing postoperative delirium (POD).

METHODS

We conducted a systematic search for randomized controlled trials (RCTs) published through December 2022. The primary outcome was efficacy based on the incidence of POD (POD-I). Secondary outcomes included efficacy and safety according to the length of hospital or intensive care unit stay, in-hospital mortality, and adverse events. Subgroup analyses of POD-I were based on the type and dose of drug (low- and high-dose melatonin, ramelteon), the postoperative period (early or late), and the type of surgery.

RESULTS

In the analysis (16 RCTs, 1981 patients), POD-I was lower in the treatment group than in the control group (risk ratio [RR] = 0.57). POD-I was lower in the high-dose melatonin group than in the control group (RR = 0.41), whereas no benefit was observed in the low-dose melatonin and ramelteon groups. POD-I was lower in the melatonin group in the early postoperative period (RR = 0.35) and in patients undergoing cardiopulmonary surgery (RR = 0.54).

CONCLUSION

Perioperative melatonin or melatonin agonist treatment suppressed POD without severe adverse events, particularly at higher doses, during the early postoperative period, and after cardiopulmonary surgery.

Increased IgA-mediated responses to the gut paracellular pathway and blood-brain barrier proteins predict delirium due to hip fracture in older adults

Introduction

Delirium is accompanied by immune response system activation, which may, in theory, cause a breakdown of the gut barrier and blood-brain barrier (BBB). Some results suggest that the BBB is compromised in delirium, but there is no data regarding the gut barrier. This study investigates whether delirium is associated with impaired BBB and gut barriers in elderly adults undergoing hip fracture surgery.

Methods

We recruited 59 older adults and measured peak Delirium Rating Scale (DRS) scores 2-3 days after surgery, and assessed plasma IgG/IgA levels (using ELISA techniques) for zonulin, occludin, claudin-6, β-catenin, actin (indicating damage to the gut paracellular pathway), claudin-5 and S100B (reflecting BBB damage), bacterial cytolethal distending toxin (CDT), LPS-binding protein (LBP), lipopolysaccharides (LPS), Porphyromonas gingivalis, and Helicobacter pylori.

Results

Results from univariate analyses showed that delirium is linked to increased IgA responses to all the self-epitopes and antigens listed above, except for LPS. Part of the variance (between 45-48.3%) in the peak DRS score measured 2-3 days post-surgery was explained by independent effects of IgA directed to LPS and LBP (or bacterial CDT), baseline DRS scores, and previous mild stroke. Increased IgA reactivity to the paracellular pathway and BBB proteins and bacterial antigens is significantly associated with the activation of M1 macrophage, T helper-1, and 17 cytokine profiles.

Conclusion

Heightened bacterial translocation, disruption of the tight and adherens junctions of the gut and BBB barriers, elevated CDT and LPS load in the bloodstream, and aberrations in cell-cell interactions may be risk factors for delirium.

Associations between depression symptom burden and delirium risk: a prospective cohort study

BACKGROUND AND OBJECTIVES

Delirium and depression are increasingly common in aging. There is considerable clinical overlap, including shared symptoms and comorbid conditions, including Alzheimer's disease (AD), functional decline, and mortality. Despite this, the long-term relationship between depression and delirium remains unclear. This study assessed the associations of depression symptom burden and its trajectory with delirium risk in a 12-year prospective study of older individuals during hospitalization.

RESEARCH DESIGN AND METHODS

319,141 UK biobank participants between 2006-2010 (mean 58y [range 37-74, SD=8], 54% female) reported frequency (0-3) of four depressive symptoms (mood, disinterest, tenseness, or lethargy) in the preceding 2 weeks, and aggregated into a depressive symptom burden score (0-12). New-onset delirium was obtained from hospitalization records during 12y median follow-up. 40,451 (mean age 57±8; range 40-74y) had repeat assessment on average 8y after their first. Cox proportional hazard models examined whether depression symptom burden and trajectory predicted incident delirium during hospitalization.

RESULTS

5,753 (15 per 1000) newly developed delirium during follow-up. Increased risk for delirium was seen for mild (aggregated scores 1-2, hazards ratio, HR=1.16, [95% confidence interval 1.08-1.25], p<0.001), modest (scores 3-5, 1.30 [1.19-1.43], p<0.001) and severe (scores ≥ 5, 1.38 [1.24-1.55], p<0.001) depressive symptoms, versus none in the fully adjusted model. These findings were independent of the number of hospitalizations and consistent across hospitalization settings (e.g., surgical, medical, or critical care) and specialty (e.g., neuropsychiatric, cardiorespiratory or other). Worsening depression symptoms (≥1 point increase), compared to no change/improved score, were associated with an additional 39% increased risk (1.39 [1.03-1.88], p=0.03) independent of baseline depression burden. The association was strongest in those over 65y at baseline (p for interaction <0.001).

DISCUSSION AND IMPLICATIONS

Depression symptom burden and worsening trajectory predicted delirium risk during hospitalization. Increased awareness of subclinical depression symptoms may be warranted for delirium prevention.

Association between remimazolam and postoperative delirium in older adults undergoing elective cardiovascular surgery: a prospective cohort study

PURPOSE

Postoperative delirium is one of the most common complications after cardiovascular surgery in older adults. Benzodiazepines are a reported risk factor for delirium; however, there are no studies investigating remimazolam, a novel anesthetic agent. Therefore, we prospectively investigated the effect of remimazolam on postoperative delirium.

METHODS

We included elective cardiovascular surgery patients aged ≥ 65 years at Hamamatsu University Hospital between August 2020 and February 2022. Patients who received general anesthesia with remimazolam were compared with those who received other anesthetics (control group). The primary outcome was delirium within 5 days after surgery. Secondary outcomes were delirium during intensive care unit stay and hospitalization, total duration of delirium, subsyndromal delirium, and differences in the Mini-Mental State Examination scores from preoperative to postoperative days 2 and 5. To adjust for differences in the groups' baseline covariates, we used stabilized inverse probability weighting as the primary analysis and propensity score matching as the sensitivity analysis.

RESULTS

We enrolled 200 patients; 78 in the remimazolam group and 122 in the control group. After stabilized inverse probability weighting, 30.3% of the remimazolam group patients and 26.6% of the control group patients developed delirium within 5 days (risk difference, 3.8%; 95% confidence interval -11.5% to 19.1%; p = 0.63). The secondary outcomes did not differ significantly between the groups, and the sensitivity analysis results were similar to those for the primary analysis.

CONCLUSION

Remimazolam was not significantly associated with postoperative delirium when compared with other anesthetic agents.

The effect of melatonin on cognitive functions following coronary artery bypass grafting: A triple-blind randomized-controlled trial

Background

Cognitive dysfunction presents one of the chief causes of postoperative morbidity. Melatonin as a neurohormone can improve neurocognitive functioning and sleep disorders. We evaluated the effect of melatonin on the postoperative cognitive function of patients undergoing coronary artery bypass grafting (CABG).

Materials and Methods

A triple-blind randomized-controlled trial was conducted on 66 CABG candidates in Namazee Hospital (Shiraz, Iran). Patients were assigned equally into two groups receiving melatonin 10 mg or a placebo daily for 4 weeks before surgery and 2 days after surgery in the intensive care unit. The Mini-Mental State Examination (MMSE), Tower of London (ToL), and Wechsler Adults Intelligence Scale-Revised (WAIS-R) cognitive function tests were performed in both groups 4 weeks before surgery (time point 1), 2 days after surgery (time point 2), and 6 weeks after initial administration of melatonin (time point 3).

Results

The mean change score (time point 3-time point 1) differed significantly between the two groups in the MMSE (P ≤ 0.001), ToL total score (P = 0.001), and WAIS-R general IQ (P ≤ 0.001), picture completion (P ≤ 0.001), vocabulary (P = 0.024), and digit span (P = 0.01). On the other hand, no significant differences were detected in the WAIS-R block design, ToL total time delay, ToL total lab, and ToL total result scores.

Conclusion

The MMSE and WAIS-R tests revealed that melatonin might have prophylactic effects against postoperative cognitive disturbance in patients undergoing elective CABG.

Delusions and Hallucinations Are Associated With Greater Severity of Delirium

BACKGROUND

The 3 core domains of delirium (cognitive, higher level thinking, circadian) do not include the less common noncore psychotic symptoms. However, psychosis might inform about perturbations of neural circuitry, outcomes, or suggest tailored clinical management.

OBJECTIVE

We assessed for the first time the relationships between psychosis and other characteristics of delirium in patients without confounders for delirium phenotype, such as dementia or antipsychotics treatment.

METHODS

Cross-sectional analysis of 366 adults with delirium per the Delirium Rating Scale Revised-98, whose items distinguish hallucinations and delusions from other types of misperceptions and abnormal thought content, assessed during the preceding 24 hours to capture symptom severity fluctuation. The relationship of psychosis with other delirium characteristics was assessed using bivariate comparisons and analysis of variance as appropriate for groups with no psychosis and any psychosis (hallucinations and/or delusions), and subgroups with only hallucinations, only delusions, or both. A discriminant logistic model assessed variables associated with presence of any psychotic features versus none.

RESULTS

Delirium with any psychotic features occurred in 44.5% (163 of 366). Of the 366, 119 (32.5%) had only hallucinations (Hall), 14 (3.8%) had only delusions (Del), and 30 (8.2%) had both (Both). In the psychotic group (n = 163), 73.0% were Hall, 8.6% Del, and 18.4% Both. All psychotic patient groupings had significantly greater delirium severity on the Delirium Rating Scale Revised-98. Delusions and hallucinations were discordant for occurring together. The discriminant model found increased odds of having psychosis as 3 symptom severities increased (visuospatial ability, thought process, and sleep-wake cycle) where these each represented a delirium core domain. The noncore symptom of lability of affect had high odds ratio for psychosis, while motor retardation reduced odds of psychosis in this model.

CONCLUSIONS

Consistent with prior reports, psychosis occurred in less than half of delirious patients with delusions being infrequent, and an association with affective lability was found. We are the first to report that psychotic features are a marker for more severe delirium affecting all core domains. Given that previous functional magnetic resonance imaging research found a correlation between neural network dysconnectivity with greater severity of delirium, psychotic symptoms might be a clinical marker for greater underlying cerebral cortical neural circuitry dysfunction.

E4BP4 Coordinates Circadian Control of Cognition in Delirium

Improved understanding of the etiologies of delirium, a common and severe neuropsychiatric syndrome, would facilitate the disease prevention and treatment. Here, the authors invesitgate the role of circadian rhythms in the pathogenesis of delirium. They observe perturbance of circadian rhythms in mouse models of delirium and disrupted clock gene expression in patients with delirium. In turn, physiological and genetic circadian disruptions sensitize mice to delirium with aggravated cognitive impairment. Likewise, global deletion of E4bp4 (E4 promoter-binding protein), a clock gene markedly altered in delirium conditions, results in exacerbated delirium-associated cognitive decline. Cognitive decline in delirium models is attributed to microglial activation and impaired long-term potentiation in the hippocampus. Single-cell RNA-sequencing reveals microglia as the regulatory target of E4bp4. E4bp4 restrains microglial activation via inhibiting the ERK1/2 signaling pathway. Supporting this, mice lacking in microglial E4bp4 are delirious prone, whereas mice with E4bp4 specifically deleted in hippocampal CA1 neurons have a normal phenotype. Mechanistically, E4bp4 inhibits ERK1/2 signaling by trans-repressing Mapk1/3 (genes encoding ERK1/2) via direct binding to a D-box element in the promoter region. These findings define a causal role of clock dysfunction in delirium development and indicate E4bp4 as a regulator of cognition at the crosstalk between circadian clock and delirium.

Delirium disorder: Unity in diversity

OBJECTIVE

The first objective of this review is to explore the factors that have led to and maintain the division between delirium and acute encephalopathy. The second is to explore the value of harmonizing them through the model of delirium disorder.

METHOD

This narrative review outlines major distinctions between delirium and acute encephalopathy. It also compares them with the model of delirium disorder, which seeks not only to integrate them but also to offer a broader palette of treatment targets.

RESULTS

Delirium implies an underlying acute encephalopathy, whereas acute encephalopathy presents as a spectrum from subsyndromal delirium to coma. Key factors that differentiate these two models include tradition, nuances of the models themselves, linguistic connotations, evoked responses from clinicians, implications of preventability and responsibility, cultural perceptions of non-pharmacological vs pharmacological interventions and economic incentives. A validated set of pathophysiological subtypes may ultimately help link the delirium-spectrum phenotype with various acute encephalopathies.

CONCLUSIONS

Developing a coherent clinical and scientific approach to this set of conditions demands that we first develop a coherent understanding of the conditions themselves and how they relate to one another. Such an approach must embrace the tension between a convergent phenotype and its diverse biological underpinnings.

Melatonin and melatonin-receptor agonists to prevent delirium in hospitalized older adults: An umbrella review

BACKGROUND

Alterations in circadian rhythm play an important role in the development of delirium. In this umbrella review, we examined the efficacy of melatonin and ramelteon for delirium prevention in hospitalized older adults.

METHODS

Umbrella review methodology from the Joanna Briggs Institute guided the review process. Only meta-analyses were included. Risk of bias was evaluated using the AMSTAR-2 checklist.

RESULTS

Three meta-analyses were included in this review. The quality of studies was low-to-moderate. Two meta-analyses reported a significant reduction in delirium using melatonin or ramelteon (pooled OR and 95% confidence intervals ranged from 0.41 [0.19-0.86] to 0.63 [0.46-0.87]). Melatonergics significantly reduced delirium on medical units (OR = 0.25, 95% CI 0.07-0.88) but not surgical units (OR = 0.62, 0.16-2.43). Heterogenity was high, with I² ranging from 72.14% to 84%.

CONCLUSIONS

Melatonergics appear to prevent delirium among hospitalized older adults, particularly those on medical units. Based on these results, providers may consider using melatonergics as complements to high-quality multicomponent delirium prevention.

Association of natural light exposure and delirium according to the presence or absence of windows in the intensive care unit

Background

Patients in the intensive care unit (ICU) have increased risks of delirium, which is associated with worse outcomes. As pharmacologic treatments for delirium are ineffective, prevention is important. Nonpharmacologic preventive strategies include exposure to natural light and restoring circadian rhythm. We investigated the effect of exposure to natural light through windows on delirium in the ICU.

Methods

This retrospective cohort study assessed all patients admitted to the medical ICU of a university-affiliated hospital between January and June 2020 for eligibility. The ICU included 12 isolation rooms, six with and six without windows. Patients with ICU stays of >48 hours were included and were divided into groups based on their admission to a single room with (window group) or without windows (windowless group). The primary outcome was the cumulative incidence of delirium. The secondary outcomes were the numbers of delirium- and mechanical ventilation-free days, ICU and hospital length of stay, and in-ICU and 28-day mortalities.

Results

Of the 150 included patients (window group: 83 [55.3%]; windowless group: 67 [44.7%]), the cumulative incidence of delirium was significantly lower in the window group than in the windowless group (21.7% vs. 43.3%; relative risk, 1.996; 95% confidence interval [CI], 1.220–3.265). Other secondary outcomes did not differ between groups. Admission to a room with a window was independently associated with a decreased risk of delirium (adjusted odds ratio, 0.318; 95% CI, 0.125–0.805).

Conclusions

Exposure to natural light through windows was associated with a lower incidence of delirium in the ICU.

Circadian Synchrony: Sleep, Nutrition, and Physical Activity

The circadian clock in mammals regulates the sleep/wake cycle and many associated behavioral and physiological processes. The cellular clock mechanism involves a transcriptional negative feedback loop that gives rise to circadian rhythms in gene expression with an approximately 24-h periodicity. To maintain system robustness, clocks throughout the body must be synchronized and their functions coordinated. In mammals, the master clock is located in the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN is entrained to the light/dark cycle through photic signal transduction and subsequent induction of core clock gene expression. The SCN in turn relays the time-of-day information to clocks in peripheral tissues. While the SCN is highly responsive to photic cues, peripheral clocks are more sensitive to non-photic resetting cues such as nutrients, body temperature, and neuroendocrine hormones. For example, feeding/fasting and physical activity can entrain peripheral clocks through signaling pathways and subsequent regulation of core clock genes and proteins. As such, timing of food intake and physical activity matters. In an ideal world, the sleep/wake and feeding/fasting cycles are synchronized to the light/dark cycle. However, asynchronous environmental cues, such as those experienced by shift workers and frequent travelers, often lead to misalignment between the master and peripheral clocks. Emerging evidence suggests that the resulting circadian disruption is associated with various diseases and chronic conditions that cause further circadian desynchrony and accelerate disease progression. In this review, we discuss how sleep, nutrition, and physical activity synchronize circadian clocks and how chronomedicine may offer novel strategies for disease intervention.

Intermittent fasting in paediatric critical illness: The properties and potential beneficial effects of an overnight fast in the PICU

Although evidence for the superiority of continuous feeding over intermittent feeding is lacking, in most paediatric intensive care units (PICU) artificial feeding is administered continuously for 24 h per day. Until now, studies in PICU on intermittent feeding have primarily focused on surrogate endpoints such as nutritional intake and gastro-intestinal complaints and none have studied the effects of an extended fasting period. Intermittent fasting has been proven to have many health benefits in both animal and human studies. The observed beneficial effects are based on multiple metabolic and endocrine changes that are presumed crucial in critical illness as well. One key element is the transition to ketone body metabolism, which, among others, contributes to the stimulation of several cellular pathways involved in stress resistance (neuro)plasticity and mitochondrial biogenesis, and might help preserve brain function. Secondly, the fasting state stimulates the activation of autophagy, a process that is crucial for cellular function and integrity. Of the different intermittent fasting strategies investigated, time-restricted feeding with a daily extended fasting period appears most feasible in the PICU. Moreover, planning the fasting period overnight could help maintain the circadian rhythm. Although not investigated, such an overnight intermittent fasting strategy might improve the metabolic profile, feeding tolerance and perhaps even have beneficial effects on tissue repair, reperfusion injury, muscle weakness, and the immune response. Future studies should investigate practical implications in critically ill children and the optimal duration of the fasting periods, which might be affected by the severity of illness and by age.

Effects of general versus subarachnoid anaesthesia on circadian melatonin rhythm and postoperative delirium in elderly patients undergoing hip fracture surgery: A prospective cohort clinical trial

BACKGROUND

Circadian rhythm disturbance is common postoperatively in older patients with hip fractures, which may contribute to the development of postoperative delirium (POD). As a reliable biomarker of endogenous circadian rhythms, melatonin regulates the sleep-wake cycle and environmental adaptation, and its secretory rhythm may be modified by anaesthesia and surgery. This study compared the impact of subarachnoid anaesthesia (SA) and general anaesthesia (GA), on the peak of melatonin secretion (primary outcome), the circadian rhythm of melatonin, cortisol and sleep, and the POD incidence (secondary outcome).

METHODS

In this prospective cohort observational study, hip fracture surgery patients were enrolled and assigned to receive either SA or GA. Postoperative plasma melatonin and cortisol levels were dynamically measured every six hours on seven time-points, and the circadian rhythm parameters including mesor, amplitude, and acrophase were calculated. Subjective and objective sleep assessments were performed by sleep diaries and sleep trackers, respectively. The Confusion Assessment Method was used twice daily by a specific geriatrician to screen for POD occurrence.

FINDINGS

In a cohort of 138 patients who underwent hip fracture surgery, the circadian rhythm disruption of the patients in the GA group (n=69) was greater than the SA group (n=69). Compared with SA, GA provided the lower peak concentration, mesor, and amplitude of melatonin secretion on postoperative day 1 (p < 0.05). Patients in the GA group experienced higher awakenings, more sleep deprivation, and poor sleep quality on surgery day (p < 0.05). A proportion of 12 patients in the SA group (17.4%) and 24 patients in the GA group (34.8%) experienced POD (p = 0.020).

INTERPRETATION

These results suggest that SA may be superior to GA in elderly patients undergoing hip fracture surgery as SA is associated with less impairment of the melatonin rhythm and sleep patterns, and fewer POD occurrences.

FUNDING

The study was supported by the National Natural Science Foundation of China (81971012, 81873726, 81901095, 81701052, and 81801070), Key Clinical Projects of Peking University Third Hospital (BYSYZD2019027), and Peking University "Clinical Medicine plus X" Youth Project (PKU2020LCXQ016).

Expression of HO1 and PER2 can predict the incidence of delirium in trauma patients with concomitant brain injury

Intensive care unit (ICU)-acquired delirium is associated with adverse outcome in trauma patients with concomitant traumatic brain injury (TBI), but diagnosis remains challenging. Quantifying circadian disruption by analyzing expression of the circadian gene period circadian regulator 2 (PER2) and heme oxygenase 1 (HO1), which determines heme turnover, may prove to be potential diagnostic tools. Expression of PER2 and HO1 was quantified using qPCR from blood samples 1 day and 7 days after trauma. Association analysis was performed comparing mRNA expression levels with parameters of trauma (ISS—injury severity score), delirium, acute kidney injury (AKI) and length of ICU stay. 48 polytraumatized patients were included (equal distribution of TBI versus non-TBI) corrected for ISS, age and gender using a matched pairs approach. Expression levels of PER2 and HO1 were independent of age (PER2: P = 0.935; HO1: P = 0.988), while expression levels were significantly correlated with trauma severity (PER2: P = 0.009; HO1: P < 0.001) and longer ICU length of stay (PER2: P = 0.018; HO1: P < 0.001). High expression levels increased the odds of delirium occurrence (PER2: OR = 4.32 [1.14–13.87]; HO1: OR = 4.50 [1.23–14.42]). Patients with TBI showed a trend towards elevated PER2 (OR = 3.00 [0.84–9.33], P = 0.125), but not towards delirium occurrence (P = 0.556). TBI patients were less likely to develop AKI compared to non-TBI (P = 0.022). Expression levels of PER2 and HO1 correlate with the incidence of delirium in an age-independent manner and may potentially improve diagnostic algorithms when used as delirium biomarkers.

Trial registration: German Clinical Trials Register (Trial-ID DRKS00008981; Universal Trial Number U1111-1172-6077; Jan. 18, 2018).

Baseline sleep as a predictor of delirium after surgical aortic valve replacement: A feasibility study

OBJECTIVE

The goal is to assess the feasibility of conducting unattended (type II) sleep studies before surgical aortic valve replacement (SAVR) to examine the relationship between baseline sleep measures and postoperative delirium.

METHODS

This single-site study recruited 18 of 20 study referrals with aortic stenosis undergoing first lifetime SAVR. Subjects completed a home-based type II sleep study. Delirium was assessed postoperative days 1-5. Exact logistic regression was used to determine whether sleep efficiency or apnea/hypopnea index predicts delirium.

RESULTS

Of 18 study participants, 15 successfully completed a home sleep study (mean age: 71.7 +/- 8.1 years old; 10 male subjects). Five subjects (33.3%) developed delirium. Preliminary analyses found that greater sleep efficiency was associated with a large reduction in delirium odds but was not statistically significant (OR = 0.31, 95% CI: 0.06, 1.03, p = 0.057). The point estimate of the relationship between apnea/hypopnea index and delirium was not similarly sizeable (OR 1.10, 95% CI: 0.35, 3.37, p = 0.85).

CONCLUSIONS

Our findings suggest that home type II sleep studies before SAVR are feasible, and they support adequately powered studies investigating type II home sleep studies as a predictor of postoperative delirium and other important postsurgical outcomes.

International Expert Opinions and Recommendations on the Use of Melatonin in the Treatment of Insomnia and Circadian Sleep Disturbances in Adult Neuropsychiatric Disorders

Introduction: Insomnia and circadian rhythm disorders, such as the delayed sleep phase syndrome, are frequent in psychiatric disorders and their evaluation and management in early stages should be a priority. The aim of this paper was to express recommendations on the use of exogenous melatonin, which exhibits both chronobiotic and sleep-promoting actions, for the treatment of these sleep disturbances in psychiatric disorders. Methods: To this aim, we conducted a systematic review according to PRISMA on the use of melatonin for the treatment of insomnia and circadian sleep disorders in neuropsychiatry. We expressed recommendations for the use of melatonin in psychiatric clinical practice for each disorder using the RAND/UCLA appropriateness method. Results: We selected 41 studies, which included mood disorders, schizophrenia, substance use disorders, attention deficit hyperactivity disorders, autism spectrum disorders, neurocognitive disorders, and delirium; no studies were found for both anxiety and eating disorders. Conclusion: The administration of prolonged release melatonin at 2-10 mg, 1-2 h before bedtime, might be used in the treatment of insomnia symptoms or comorbid insomnia in mood disorders, schizophrenia, in adults with autism spectrum disorders, neurocognitive disorders and during sedative-hypnotics discontinuation. Immediate release melatonin at <1 mg might be useful in the treatment of circadian sleep disturbances of neuropsychiatric disorders.

The Nexus Between Sleep Disturbance and Delirium Among Intensive Care Patients

Sleep in intensive care is hampered due to many factors; the clinical environment itself exacerbates sleep disturbance. Research suggests that interventions aimed at improving sleep quality have produced positive effects in reducing incidences and duration of delirium. Sleep disturbance is well documented among intensive care patients; however, its prognostic impact is not fully understood. Delirium, disproportionally prevalent among intensive care patients, has significant prognostic factors related to patient outcomes, in which sleep disturbance often is present. The relationship between sleep disturbance and delirium is complex, sharing commonalities in relation to neurobiological and neurohormonal alterations, which may contribute to a bidirectional relationship.

Effects of general versus regional anaesthesia on circadian melatonin rhythm and its association with postoperative delirium in elderly patients undergoing hip fracture surgery: study protocol for a prospective cohort clinical trial

INTRODUCTION

Postoperative delirium (POD) is a common neurological complication after hip fracture surgery and is associated with high morbidity and mortality in elderly patients. Although the specific mechanism of POD remains unclear, circadian rhythm disruptions have recently drawn increased attention. To date, only limited postoperative time points of plasma melatonin level measurements were recorded in previous studies, and such data cannot represent a comprehensive melatonin rhythm. The process of anaesthesia (either general anaesthesia (GA) or regional anaesthesia (RA)) is known to influence the melatonin rhythm. However, how these two anaesthesia methods differently affect the postoperative melatonin rhythm is still unknown. Therefore, we hypothesise that RA may attenuate the disruption of the melatonin rhythm, which might decrease the incidence of POD in elderly patients undergoing hip surgery.

METHODS AND ANALYSIS

In this prospective cohort clinical trial, 138 patients scheduled for hip fracture surgery will be divided into two groups to receive either GA or RA. The primary aim is to compare the circadian rhythm of melatonin secretion between the two groups and explore its association with the incidence of POD.

ETHICS AND DISSEMINATION

The study has been approved by the Medical Science Research Ethics Committees of Beijing Jishuitan Hospital (JLKS201901-04). The results of the study will be published in peer-reviewed international journals.

TRIAL REGISTRATION NUMBER

ChiCTR1900027393.

Effects of Ramelteon on the Prevention of Postoperative Delirium in Older Patients Undergoing Orthopedic Surgery: The RECOVER Randomized Controlled Trial

OBJECTIVES

Postoperative delirium, associated with negative consequences including longer hospital stays and worse cognitive and physical outcomes, is frequently accompanied by sleep-wake disturbance. Our objective was to evaluate the efficacy and short-term safety of ramelteon, a melatonin receptor agonist, for the prevention of postoperative delirium in older patients undergoing orthopedic surgery.

DESIGN

A quadruple-masked randomized placebo-controlled trial (Clinical Trials.gov NCT02324153) conducted from March 2017 to June 2019.

SETTING

Tertiary academic medical center.

PARTICIPANTS

Patients aged 65 years or older, undergoing elective primary or revision hip or knee replacement.

INTERVENTION

Ramelteon (8 mg) or placebo MEASUREMENTS: Eighty participants were randomized to an oral gel cap of ramelteon or placebo for 3 consecutive nights starting the night before surgery. Trained research staff conducted delirium assessments for 3 consecutive days starting on postoperative day (POD) 0, after recovery from anesthesia, and on to POD2. A delirium diagnosis was based upon DSM-5 criteria determined by expert panel consensus.

RESULTS

Of 80 participants, five withdrew consent (one placebo, four ramelteon) and four were excluded (four ramelteon) after randomization. Delirium incidence during the 2 days following surgery was 7% (5 of 71) with no difference between the ramelteon versus placebo: 9% (3 of 33) and 5% (2 of 38), respectively. The adjusted odds ratio for postoperative delirium as a function of assignment to the ramelteon treatment arm was 1.28 (95% confidence interval: 0.21-7.93; z-value 0.27; p-value = 0.79). Adverse events were similar between the two groups.

CONCLUSION

In older patients undergoing elective primary or revision hip or knee replacement, ramelteon was not efficacious in preventing postoperative delirium.

Delirium in the acute hospital setting: the role of psychiatry

In this overview we discuss the role of psychiatry in managing delirium in acute hospital admissions. We briefly discuss the role psychiatry can offer in four main domains: (a) assessment; (b) management; (c) recovery; and (d) paradigm, education and research. In the assessment section we discuss accurately detecting delirium in the context of comorbid mixed neuropsychiatric syndromes, including depression and dementia, and the clinical importance of delirium subtyping. The management section briefly outlines pharmacological and non-pharmacological approaches to delirium and their evidence-based rationale. The recovery section focuses on the effect delirium can have on cognitive decline, mental health and long-term health, including functional outcome and need for institutional care after hospital discharge. Finally, we outline the role of psychiatry in delirium research and education. We hope that this article will encourage clinicians to reflect on their current practice and consider holistic and evidence-based care for this vulnerable population in the acute hospital setting.

Neurologic Manifestations of Systemic Disease: Sleep Disorders

Purpose of review

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

Recent findings

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

Summary

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

Study protocol for a prospective randomised double-blind placebo-controlled clinical trial investigating a Better Outcome with Melatonin compared to Placebo Administered to normalize sleep-wake cycle and treat hypoactive ICU Delirium: the Basel BOMP-AID study

INTRODUCTION

Delirium is frequently observed in the intensive care unit (ICU) population, in particular. Until today, there is no evidence for any reliable pharmacological intervention to treat delirium. The Basel BOMP-AID (Better Outcome with Melatonin compared to Placebo Administered to normalize sleep-wake cycle and treat hypoactive ICU Delirium) randomised trial targets improvement of hypoactive delirium therapy in critically ill patients and will be conducted as a counterpart to the Basel ProDex Study (Study Protocol, BMJ Open, July 2017) on hyperactive and mixed delirium. The aim of the BOMP-AID trial is to assess the superiority of melatonin to placebo for the treatment of hypoactive delirium in the ICU. The study hypothesis is based on the assumption that melatonin administered at night restores a normal circadian rhythm, and that restoration of a normal circadian rhythm will cure delirium.

METHODS AND ANALYSIS

The Basel BOMP-AID study is an investigator-initiated, single-centre, randomised controlled clinical trial for the treatment of hypoactive delirium with the once daily oral administration of melatonin 4 mg versus placebo in 190 critically ill patients. The primary outcome measure is delirium duration in 8-hour shifts. Secondary outcome measures include delirium-free days and death at 28 days after study inclusion, number of ventilator days, length of ICU and hospital stay, and sleep quality. Patients will be followed after 3 and 12 months for activities of daily living and mortality assessment. Sample size was calculated to demonstrate superiority of melatonin compared with placebo regarding the duration of delirium. Results will be presented using an intention-to-treat approach.

ETHICS AND DISSEMINATION

This study has been approved by the Ethics Committee of Northwestern and Central Switzerland and will be conducted in compliance with the protocol, the current version of the Declaration of Helsinki, the International Conference on Harmonisation (ICH) of technical requirements for registration of pharmaceuticals for human use; Good Clinical Practice (GCP) or ISO EN 14155 (as far as applicable), as well as all national legal and regulatory requirements. Study results will be presented in international conferences and published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT03438526.

PROTOCOL VERSION

Clinical Study Protocol Version 3, 10.03.2019.

A Role for the Adenosine ADORA2B Receptor in Midazolam Induced Cognitive Dysfunction

BACKGROUND

We recently reported a role for the circadian rhythm protein Period 2 (PER2) in midazolam induced cognitive dysfunction. Based on previous studies showing a critical role for the adenosine A2B receptor (ADORA2B) in PER2 regulation, we hypothesized that hippocampal ADORA2B is crucial for cognitive function.

METHODS

Midazolam treated C57BL/6J mice were analyzed for Adora2b hippocampal mRNA expression levels, and spontaneous T-maze alternation was determined in Adora2b-/- mice. Using the specific ADORA2B agonist BAY-60-6583 in midazolam treated C57BL/6J mice, we analyzed hippocampal Per2 mRNA expression levels and spontaneous T-maze alternation. Finally, Adora2b-/- mice were assessed for mRNA expression of markers for inflammation or cognitive function in the hippocampus.

RESULTS

Midazolam treatment significantly downregulated Adora2b or Per2 mRNA in the hippocampus of C57BL/6J mice, and hippocampal PER2 protein expression or T-maze alternation was significantly reduced in Adora2b-/- mice. ADORA2B agonist BAY-60-6583 restored midazolam mediated reduction in spontaneous alternation in C57BL/6J mice. Analysis of hippocampal Tnf-α or Il-6 mRNA levels in Adora2b-/- mice did not reveal an inflammatory phenotype. However, C-fos, a critical component of hippocampus-dependent learning and memory, was significantly downregulated in the hippocampus of Adora2b-/- mice.

CONCLUSION

These results suggest a role of ADORA2B in midazolam induced cognitive dysfunction. Further, our data demonstrate that BAY-60-6583 treatment restores midazolam induced cognitive dysfunction, possibly via increases of Per2. Additional mechanistic studies hint towards C-FOS as another potential underlying mechanism of memory impairment in Adora2b-/- mice. These findings suggest the ADORA2B agonist as a potential therapy in patients with midazolam induced cognitive dysfunction.

Impact of Light Intensity on Sleep of Patients in the Intensive Care Unit: A Prospective Observational Study

Aims and objectives

Sleep deprivation in the intensive care unit (ICU) has been linked to numerous complications. Light levels might impact the sleep of patients in the ICU. The aim of the study was to measure light levels during sleep-protected time in the ICU and to assess the impact of light intensity on sleep quantity/quality.

Materials and methods

This prospective, observational study was conducted in a 10-bed, mixed surgical/medical ICU. For measuring light levels, a commercially available smartphone application was used. The measurements were performed between 23:30 and 06:15 hours at 15-minute intervals. To assess sleep quantity, we used Patient's Sleep Observation Behavioral Tool and to assess sleep quality, we used Richards-Campbell Sleep Scale.

Results

The median number of time points at which patients were asleep was 20 (interquartile range, IQR 14-23) out of 25 (5 hours). The median self-reported quality of sleep (overall score) was 49 (IQR 28-71). The median values for individual questions are: question 1 (sleep depth)-54.0 (IQR 37-78), question 2 (sleep latency)-40.5 (IQR 6-90), question 3 (awakenings)-52.5 (IQR 28-76), question 4 (returning to sleep)-25.5 (IQR 11-78), and question 5 (sleep quality)-67.5 (IQR 5-76). No correlation was found between self-reported sleep quality and time spent asleep (p = 0.36). There was no correlation between average light levels during sleep-protected time and sleep quantity (p = 0.42)/sleep quality (p = 0.13). There was a correlation between average (13 ± 5 lux) light levels before sleep-protected time and sleep quality (p = 0.008).

Conclusion

Mean light levels of 11 ± 9 lux during sleep-protected time have no negative impact on quantity and quality of sleep in intensive care unit patients. Light levels up to 18 lux directly before falling asleep improve patients' self-reported quality of sleep in the ICU.

Clinical significance

Finding safe levels of light intensity during sleep-protected time in ICU.

How to cite this article

Czempik PF, Jarosińska A, Machlowska K, Pluta M. Impact of Light Intensity on Sleep of Patients in the Intensive Care Unit: A Prospective Observational Study. Indian J Crit Care Med 2020;24(1):33-37.

Effect of Suvorexant on Nocturnal Delirium in Elderly Patients with Alzheimer's Disease: A Case-series Study

Suvorexant, an orexin receptor antagonist used for insomnia, has been shown to have a preventive effect on delirium in a randomized placebo-controlled trial. However, its effectiveness in the management of nocturnal delirium has not yet been determined. Here we report four cases in which elderly patients with moderate to severe Alzheimer’s disease who developed nocturnal delirium were treated with suvorexant. In case 1, 15 mg suvorexant was initiated to manage nocturnal delirium refractory to antipsychotics, antidepressants, and a Japanese herbal medicine, resulting in immediate sleep improvement. However, treatment discontinuation led to recurrence of symptoms, which were reversed by recommencing suvorexant. In case 2, as antipsychotics used for the treatment of nocturnal delirium were ineffective, 15 mg suvorexant was administered. The patient achieved rapid improvement in sleep. In case 3, the use of atypical antipsychotics for the treatment of nocturnal delirium was contraindicated, as the patient had diabetes. Therefore, 15 mg suvorexant was administered following good outcomes in cases 1 and 2, resulting in immediate sleep improvement. Finally, in case 4, 15 mg suvorexant was used as an initial medication for nocturnal delirium, and the patient showed sleep improvement immediately. Elevated orexin levels in the cerebrospinal fluid are reportedly linked to sleep deterioration in patients with moderate to severe Alzheimer’s disease. The immediate and reproducible action and effectiveness of suvorexant observed in our patients suggest that enhanced cerebral orexin activity might be associated with sleep-wake cycle disturbances due to delirium in elderly patients with Alzheimer’s disease.

Melatonergic agents in the prevention of delirium: A network meta-analysis of randomized controlled trials

Disruption of the sleep-wake cycle is a risk factor and a prodromal indicator of delirium. Melatonergic agents may thus play a role in the prevention of delirium. Based upon literature search on eight databases, this systemic review and frequentist model network meta-analysis (NMA) aimed to determine the efficacy and tolerability of melatonergic agents in delirium prevention. Six randomized controlled trials (RCTs) were included with a total of 913 adult participants (mean age = 78.8, mean female proportion = 59.4%) investigating the preventive effects of melatonergic agents in patients with high risks of developing delirium. The outcomes of NMA demonstrated significant preventive effects with 5 mg/day of melatonin [Odds Ratio (OR) = 0.21, 95% Confidence Intervals (CIs): 0.07 to 0.64], melatonin (0.5 mg/d) [OR = 0.16 (95% CIs: 0.03 to 0.75)], and ramelteon (8 mg/d) [OR = 0.28 (95% CIs: 0.12 to 0.65)] against placebo groups. According to the surface under the cumulative ranking curve (SUCRA), 0.5 mg/d of melatonin was associated with the best preventive effect. Our findings provided the rationale for recommending low-dose melatonergic agents for delirium prevention in the practice guidelines.

The Period 2 Enhancer Nobiletin as Novel Therapy in Murine Models of Circadian Disruption Resembling Delirium

OBJECTIVES

Delirium occurs in approximately 30% of critically ill patients, and the risk of dying during admission doubles in those patients. Molecular mechanisms causing delirium are largely unknown. However, critical illness and the ICU environment consistently disrupt circadian rhythms, and circadian disruptions are strongly associated with delirium. Exposure to benzodiazepines and constant light are suspected risk factors for the development of delirium. Thus, we tested the functional role of the circadian rhythm protein Period 2 (PER2) in different mouse models resembling delirium.

DESIGN

Animal study.

SETTING

University experimental laboratory.

SUBJECTS

Wildtype, Per2 mice.

INTERVENTIONS

Midazolam, lipopolysaccharide (lipopolysaccharide), constant light, nobiletin, or sham-treated animals.

MEASUREMENTS AND MAIN RESULTS

Midazolam significantly reduced the expression of PER2 in the suprachiasmatic nucleus and the hippocampus of wild-type mice. Behavioral tests following midazolam exposure revealed a robust phenotype including executive dysfunction and memory impairment suggestive of delirium. These findings indicated a critical role of hippocampal expressed PER2. Similar results were obtained in mice exposed to lipopolysaccharide or constant light. Subsequent studies in Per2 mice confirmed a functional role of PER2 in a midazolam-induced delirium-like phenotype. Using the small molecule nobiletin to enhance PER2 function, the cognitive deficits induced by midazolam or constant light were attenuated in wild-type mice.

CONCLUSIONS

These experiments identify a novel role for PER2 during a midazolam- or constant light-induced delirium-like state, highlight the importance of hippocampal PER2 expression for cognitive function, and suggest the PER2 enhancer nobiletin as potential therapy in delirium-like conditions associated with circadian disruption.

Role of Wearable Accelerometer Devices in Delirium Studies: A Systematic Review

We sought to determine the feasibility of using wearable accelerometer devices for determining delirium effects on patients' physical activity patterns and detecting delirium and delirium subtype.

DATA SOURCES

PubMed, Embase, and Web of Science.

STUDY SELECTION

Screening was performed using predefined search terms to identify original research studies using accelerometer devices for studying physical activity in relation to delirium.

DATA EXTRACTION

Key data were extracted from the selected articles.

DATA SYNTHESIS

Among the 14 studies identified, there were a total of 315 patients who wore accelerometer devices to record movements related to delirium. Eight studies (57.1%) used accelerometer devices to compare the activity of delirious and nondelirious patients. Delirious patients had lower activity levels, lower restlessness index, higher number of daytime immobility minutes, lower mean activity levels during the day, and higher mean activity levels at night. Delirious patients also had lower actual sleep time, lower sleep efficiency, fewer nighttime minutes resting, fewer minutes resting over 24 hours, and smaller change in activity from day to night. Six studies (42.9%) evaluated the feasibility of using accelerometer devices for detection of delirium and its subtype. Variables including number of postural changes during daytime, frequency of ultrashort, short, and continuous movements were significantly different among the nondelirium and the three delirium subtypes.

CONCLUSIONS

The results from the studies using accelerometer devices in studying delirium demonstrate that accelerometer devices can potentially detect the differences between delirious and nondelirious patients, detect delirium, and determine delirium subtype. We suggest the following directions as the next steps for future studies using accelerometer devices for predicting delirium: benchmark studies with longer data collection, larger and more diverse population size, incorporating related factors (e.g., medications), and evaluating delirium subtype and severity.

Sleep and Memory: The Promise of Precision Medicine

Given the complex and bidirectional nature of sleep and mild cognitive impairment/Alzheimer's disease and related dementias, a precision medicine approach to education, lifestyle changes, and early assessment in patients with a family history of snoring, sleep apnea, diabetes, and heart disease is warranted. Furthermore, a team-based approach allows for a coordinated precision diagnosis and management of common comorbid chronic illnesses. The significance of sleep disturbances in this population, contributing factors, assessment and diagnostic challenges, common sleep disorders and mechanisms, tailored behavioral and pharmacologic interventions, knowledge gaps, and future research ideas are discussed.

Early Postoperative Actigraphy Poorly Predicts Hypoactive Delirium

STUDY OBJECTIVES

Delirium is a postoperative complication accompanied by disturbances in attention, cognition, arousal, and psychomotor activity. Wrist actigraphy has been advocated to study inactivity and inferred sleep patterns during delirium. We hypothesized that altered patterns of motor activity or immobility, reflective of disordered sleep and wakefulness patterns, would serve as predictive markers of hypoactive postoperative delirium.

METHODS

Eighty-four elderly surgical patients were classified into three groups based on the timing of hypoactive delirium following surgery: intact with no delirium throughout postoperative days (POD) 0-5 (n = 51), delirium during POD 0-1 (n = 24), and delirium during POD 2-5 (n = 13). Delirium was detected on daily Confusion Assessment Method evaluations and chart review. Actigraphy measures were calculated from accelerometry signals acquired on the first postoperative day (POD 0, 16:00-23:00) and night (POD 0, 23:00-POD 1, 06:00).

RESULTS

Actigraphy metrics showed substantial interpatient variability. Among the three patient groups, only those without delirium showed greater movement during the day compared to night and also fewer minutes of night immobility (P = .03 and P = .02, Wilcoxon rank-sum tests). These patients were poorly discriminated from those with delirium during either POD 0-1 or POD 2-5, using differences in day and night activity (C-statistic, 95% confidence interval [CI]: 0.66 [0.53-0.79] and C-statistic, 95% CI: 0.71 [0.55-0.87], respectively). Inclusion of low-frequency signals improved performance of immobility measures without affecting those based on activity. Cognitively intact patients during POD 0-5 were distinguished from those with delirium during POD 0-1, based on differences in the number of day and night immobile minutes (C-statistic 0.65, 95% CI: [0.53-0.78]). Actigraphy metrics with the strongest association to delirium incidence were not reliably correlated with an increased risk during POD 0-5, when accounting for patient age, sex, intensive care unit admission, and Charlson Comorbidity Index (adjusted odds ratio of 1.7, 95% CI: [1.0-3.0], P = .09, likelihood ratio test).

CONCLUSIONS

Early postoperative wrist actigraphy metrics that serve as markers of sleep and wakefulness offer limited capacity as sole predictors or markers of hypoactive delirium.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Title: Electroencephalography Guidance of Anesthesia to Alleviate Geriatric Syndromes (ENGAGES) Study; Identifier: NCT02241655; URL: https://clinicaltrials.gov/ct2/show/NCT02241655.

Rest-Activity Rhythms and Cognitive Decline in Older Men: The Osteoporotic Fractures in Men Sleep Study

OBJECTIVE

To examine rest-activity circadian rhythm (RAR) and cognitive decline in older men.

DESIGN

Longitudinal.

SETTING

Osteoporotic Fractures in Men (MrOS) and ancillary Outcomes of Sleep Disorders in Men (MrOS Sleep) studies.

PARTICIPANTS

MrOS and MrOS Sleep participants (N=2,754; mean age 76.0 ± 5.3).

MEASUREMENTS

The Modified Mini-Mental State examination (3MS) was used to assess cognition at baseline (2003-05) and follow-up examinations (2005-06 and 2007-09). Wrist actigraphy was used to measure 24-hour activity counts at baseline. RAR variables included amplitude (strength of activity rhythm), mesor (mean activity level), pseudo F-statistic (overall circadian rhythm robustness), and acrophase (time of daily peak activity).

RESULTS

After an average of 3.4 ± 0.5 years, men with lower amplitudes, mesors, and pseudo F-statistics had greater decline in 3MS performance (amplitude: -0.7 points Q1 vs -0.5 points Q4, p<.001; mesor: -0.5 points Q1 vs -0.2 points Q4, p=.01; pseudo F-statistic: -0.5 points Q1 vs -0.3 points Q4, p<.001). Lower amplitudes and pseudo-F statistics were associated with greater odds of clinically significant cognitive decline (≥5-point decrease) (amplitude Q1 vs. Q4: odds ratio (OR)=1.4, 95% confidence interval (CI)=1.0-1.9; pseudo-F statistic Q1 vs Q4: OR=1.4, 95% CI=1.0-1.9). Men with phase-advanced acrophase had greater odds of clinically significant cognitive decline (OR=1.8, 95% CI=1.2-2.8). Results were adjusted for multiple confounders.

CONCLUSION

Several parameters of disrupted RAR (lower amplitude, pseudo F-statistic, mesor, phase-advanced acrophase) were associated with greater cognitive decline in older community-dwelling men. These findings contribute to a growing body of evidence suggesting that altered RARs are associated with cognitive decline in older adults. J Am Geriatr Soc 66:2136-2143, 2018.

Neural predisposing factors of postoperative delirium in elderly patients with femoral neck fracture

Elderly adults are more likely to develop delirium after major surgery, but there is limited knowledge of the vulnerability for postoperative delirium. In this study, we aimed to identify neural predisposing factors for postoperative delirium and develop a prediction model for estimating an individual’s probability of postoperative delirium. Among 57 elderly participants with femoral neck fracture, 25 patients developed postoperative delirium and 32 patients did not. We preoperatively obtained data for clinical assessments, anatomical MRI, and resting-state functional MRI. Then we evaluated gray matter (GM) density, fractional anisotropy, and the amplitude of low-frequency fluctuation (ALFF), and conducted a group-level inference. The prediction models were developed to estimate an individual’s probability using logistic regression. The group-level analysis revealed that neuroticism score, ALFF in the dorsolateral prefrontal cortex, and GM density in the caudate/suprachiasmatic nucleus were predisposing factors. The prediction model with these factors showed a correct classification rate of 86% using a leave-one-out cross-validation. The predicted probability computed from the logistic model was significantly correlated with delirium severity. These results suggest that the three components are the most important predisposing factors for postoperative delirium, and our prediction model may reflect the core pathophysiology in estimating the probability of postoperative delirium.

Psychiatric diagnoses and their influencing factors in patients complaining of sleep problems: A study of a psychiatric consultation-liaison service

Objective This study aimed to identify misdiagnosed or undiagnosed psychiatric disorders and the factors associated with these disorders in patients with sleep problems who are referred to a consultation-liaison service. Method Records of all inpatients receiving a consultation from the Psychiatry Department between January and December 2016 were retrospectively reviewed. Psychiatric diagnoses were analyzed using descriptive statistics, and the factors associated with the risk of these disorders in patients with sleep problems were determined by multiple logistic regression analysis. Results Of the 331 referral patients whose referral reason was simply having trouble in sleeping, only 97 patients were diagnosed with primary sleep disorder after consultation. The recognition rate of psychiatric disorders in inpatients with sleep problems among nonpsychiatric physicians was 29.3%. Anxiety (107, 45.7%) was the most common psychiatric diagnosis in patients with sleep problems followed by organic mental disorder (83, 35.5%), depression (37, 15.8%), and other mental disorders (8, 3.4%). Multiple logistic regression analysis revealed that a course >1 month (OR = 3.656, 95% CI = 2.171-6.156, p = 0.000) and sleep-wake rhythm disturbances (OR = 25.008, 95% CI = 5.826-107.341, p = 0.000) were associated with increased risks of psychiatric disorders. Conclusions The study showed that recognition rate of psychiatric disorders in inpatients with sleep problems was very low. A course >1 month and sleep-wake rhythm disturbances were associated with increased risks of disorders and could be used as indicators by nonpsychiatric physicians to improve diagnoses.

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

OBJECTIVE

Critically ill patients exhibit profound disturbances of circadian rhythmicity, most commonly in the form of a phase delay. We investigated the specific zeitgeber properties of a medical intensive care unit to develop a model that explained these abnormalities.

RESEARCH METHODOLOGY

Prospective, observational study conducted during 2013-2014. Twenty-four-hour ambient light (lux, 672 hours) and sound pressure levels (dBA, 504 hours) were measured in patient rooms. Patients and families were surveyed regarding their perceptions of the environment.

SETTING

University-based adult medical intensive care unit.

MAIN OUTCOME MEASURES

The timing and intensity of the ambient light-dark cycle and sound environment and the relationship of these measurements to patient/family perceptions.

RESULTS

Twenty-four-hour light-dark cycles were extremely weak and phase delayed relative to the solar cycle. Morning light averaged 12.1 (4.8, 37.2) lux, when only 24.9% ± 10.9% of available light was utilised; yet patients and families did not identify low daytime light levels as problematic. Median noise levels were invariably excessive (nighttime 47.9 [45.0, 51.3] dBA) with minimal variation, consistent with the absence of a defined rest period.

CONCLUSION

The intensive care unit functions as a near-constant routine protocol disconnected from solar time. Behavioural interventions to promote entrainment should be supported by objective measurements of light and sound.

Delirium and effect of circadian light in the intensive care unit: a retrospective cohort study

BACKGROUND

Delirium is a serious condition often experienced by critically ill patients in intensive care units (ICUs). The role of circadian light for this condition is unclear. The aim of this study was to describe incidence of delirium, risk factors for delirium, and the association between delirium and circadian light for patients in the ICU.

METHODS

This is a retrospective cohort study of all patients at a Danish ICU from 1 August 2015 to 31 January 2016. Exclusion criteria were heavy sedation, no Confusion Assessment Method for the ICU (CAM-ICU) scores, or inability to communicate in Danish. Delirium was defined as at least one positive CAM-ICU score or treatment with haloperidol. Three of nine beds at the ICU had a circadian light installation. Allocation to ICU beds with or without circadian light depended on availability at admission. Risk factors for development of delirium were analyzed by simple and multiple logistic regression.

RESULTS

We included 183 patients in the study. The incidence of delirium was 28% (95% CI 22, 35). Allocation to beds with or without circadian lighting was not associated with delirium incidence (OR 1.14; 95% CI 0.55, 2.37; P = 0.73). We found that Simplified Acute Physiology Score II (SAPS II) (OR 1.03; 95% CI 1.01, 1.06; P = 0.002), and dexmedetomidine was associated with delirium (OR 4.14; 95% CI 1.72, 10.03; P = 0.002).

CONCLUSION

In this population of patients admitted to an ICU during 6 months, the incidence of delirium was 28%. We did not find an association between circadian light and development of delirium.

Melatonin and the Prevention and Management of Delirium: A Scoping Study

Background

The therapeutic benefit of melatonin in the prevention and treatment of delirium is uncertain.

Objective

To perform a scoping study to describe the existing literature regarding the use of melatonin and ramelteon in the prevention and treatment of delirium.

Methods

We performed a scoping study using the Arksey and O’Malley framework to explore our objective. Two independent panels searched MEDLINE, OVID, EMBASE, PubMed, Google Scholar, and Cochrane Library for relevant articles up to November 2017 describing the use of melatonin and ramelteon in the prevention or management of delirium. We extracted relevant summary data from the studies and attempted to draw conclusion regarding benefit.

Results

We summarized evidence from 20 relevant articles. There were a total of nine articles: five randomized controlled trials (RCTs), two retrospective medical record reviews, one non-randomized observational study, and one case report describing the role of either melatonin or ramelteon in preventing delirium. There were a total of 11 studies studying the role of either melatonin or ramelteon in the management of established delirium. None of these were RCT and were predominantly case series and case reports. Four of the five trials studying the effect of melatonin analogs in preventing delirium reported a beneficial effect but study heterogeneity limited any broad recommendations. Similarly, the lack of any well-designed trials limits any recommendations regarding the effect of melatonin analogs in treating delirium.

Conclusion

Large, well-designed clinical trials are required to explore the potential beneficial effects of melatonin and ramelteon on delirium prevention and management.

Medical hypothesis: Light at night is a factor worth considering in critical care units

Exposure to light at night is not an innocuous consequence of modernization. There are compelling data linking long-term exposure to occupational and environmental light at night with serious health conditions, including heart disease, obesity, diabetes, and cancer. However, far less is known about the physiological and behavioral effects of acute exposure to light at night. Among healthy volunteers, acute night-time light exposure increases systolic blood pressure and inflammatory markers in the blood, and impairs glucose regulation. Whether critically ill patients in a hospital setting experience the same physiological shifts in response to evening light exposure is not known. This paper reviews the available data on light at night effects on health and wellbeing, and argues that the data are sufficiently compelling to warrant studies of how lighting in intensive care units may be influencing patient recovery.

Implementing a Multicomponent Intervention to Prevent Delirium Among Critically Ill Patients

BACKGROUND

Delirium is common among the critically ill. Nonpharmacologic interventions are reportedly effective in reducing incident delirium, but limited data specific to this population exist.

OBJECTIVES

To assess the efficacy and describe the implementation strategy of a multicomponent intervention to prevent delirium in an intensive care unit.

METHODS

A before-and-after study was conducted in an intensive care unit between May 2014 through August 2015. Adult participants were enrolled consecutively, excluding only those who refused to participate. Tailored interventions took available evidence into consideration. Components included early mobilization, physical therapy, reorientation, cognitive stimulation, drug reviews, environmental stimulation, avoidance of sensory deprivation, pain control, restraint use avoidance, and family participation. Incident delirium was assessed twice daily using the Confusion Assessment Method for the Intensive Care Unit. Multivariate logistic regression was used to control for confounders.

RESULTS

The study included 227 patients (54.7% male; mean [SD] age, 63.3 [18.3] years). Our strategy significantly reduced delirium (from 38% to 24%; relative risk, 0.62; 95% CI, 0.40–0.94; P = .02), an association that remained significant after adjusting for confounders. Adherence rates were more than 85% in all intervention domains (except daily reorientation) that were overseen by health care providers.

CONCLUSIONs

The strategy was successful in reducing delirium. Self-removals of invasive implements decreased, an observation that has not been previously described. No difference in mortality rate was seen, as has been reported in other studies. Early participation of the whole team, shared leadership, and the provision of concrete tasks were key to the success of this multicomponent intervention.

Role of Ramelteon in Reduction of As-Needed Antipsychotics in Elderly Patients with Delirium in a General Hospital Setting

BACKGROUND AND OBJECTIVE

Abnormalities in melatonin levels have been linked to delirium. This dysregulation may be offset with the use of ramelteon, a melatonin receptor agonist. The purpose of this study was to evaluate the role of ramelteon in decreasing the need for as-needed (PRN) use of antipsychotics in elderly patients with delirium.

METHODS

This was a single-center, retrospective study involving 488 patients who were placed on constant observation and received care by psychiatric service from May 2015 through October 2015. Of these patients, 125 patients were age 65 years or above, had a diagnosis of delirium, and had no standing orders for antipsychotics. These 125 patients were divided into the non-ramelteon group (who received no ramelteon and PRN antipsychotics) and the ramelteon group (who received ramelteon plus PRN antipsychotics). The use of PRN antipsychotics for agitation in each group was recorded.

RESULTS

The ramelteon group had a lower incidence of PRN antipsychotic use compared to those not given ramelteon (60 vs. 80%, p value = 0.001). After adjustment for race, age, length of stay, and gender, patients in the non-ramelteon group were more likely to have been given antipsychotics compared to those in the ramelteon group (odds ratio = 4.3, p value = 0.002).

CONCLUSION

Ramelteon use in elderly patients with delirium may be associated with statistically significant reduction of PRN antipsychotic use for agitation.

Plasma melatonin levels in hip fracture patients with and without delirium: A confirmation study

BACKGROUND

Melatonin plays a major role in maintaining circadian rhythm. Changes in melatonin metabolism might lead to circadian rhythm disturbances which are often observed in delirious patients.

AIM

To assess if high morning plasma melatonin concentrations were associated with delirium.

METHODS

Consecutive hip fracture patients aged ≥65 years were included. Delirium was assessed daily with the Confusion Assessment METHOD: Blood samples were collected at 11.00am on weekdays during first week of hospitalization. Melatonin was analyzed by liquid chromatography-tandem mass spectrometry.

RESULTS

We analyzed 389 samples of 144 participants [mean age 84.0, 70 experienced delirium]. A Generalized Estimating Equations (GEE) model with outcome melatonin level in highest tertile ( >3.36 pg/ml) and covariates delirium group (i.e. never, before, during, post delirium), cognitive impairment, age, sex and anesthesia type, was constructed. Highest melatonin levels were associated with postoperative samples (Odds Ratio(OR) 2.11 compared to preoperative samples; 95% Confidence Interval(CI) 1.17-3.82, p=0.01) and higher age (OR 1.05 per year; CI 1.01-1.11, p=0.03), but not with delirium group(p=0.35).

CONCLUSION

Undergoing surgery and aging in general may induce changes in melatonin metabolism. Future research should focus on daily multiple melatonin measurements to determine whether melatonin supplementation might be beneficial for delirium treatment or prevention.

Motor Disturbances in Elderly Medical Inpatients and Their Relationship to Delirium

Motor disturbances in delirious patients are common, but their relationship to cognition and severity of illness has not been studied. We examined motor subtypes in an older age inpatient population, their relationship to clinical variables including delirium, and their association with 1-year mortality in a prospective study, using the Confusion Assessment Method, Acute Physiology and Chronic Health Evaluation II, Montreal Cognitive Assessment (MoCA), Barthel Index, and Delirium Rating Scale-Revised 98 (DRS-R98). Motor subtypes were evaluated using 2 items of DRS-R98. Mortality rates were investigated 1 year later. Two hundred participated (mean age 81.1 [6.5]; 50% female). Thirty-four (17%) were identified with delirium. Motor subtypes were none: 119 (59.5%), hypoactive: 37 (18.5%), hyperactive: 29 (14.5%), and mixed: 15 (7.5%). Hypoactive and mixed subtypes were significantly more frequent in delirious patients. Regression analysis showed that hypoactive subtype was significantly associated with lower MoCA. No relationship between motor subtypes and mortality was found. Motor disturbances are not unique to delirium, with hypoactivity particularly associated with impaired cognition.

The effect of chronotherapy on delirium in critical care - a systematic review

BACKGROUND

Delirium is highly prevalent within critical care and is linked to adverse clinical outcomes, increased mortality and impaired quality of life. Development of delirium is thought to be caused by multiple risk factors, including disruption of the circadian rhythm. Chronotherapeutic interventions, such as light therapy, music and use of eye shades, have been suggested as an option to improve circadian rhythm within intensive care units.

AIM

This review aims to answer the question: Can chronotherapy reduce the prevalence of delirium in adult patients in critical care?

DESIGN

This study is a systematic review of quantitative studies.

RESEARCH METHOD

Six major electronic databases were searched, and a hand search was undertaken using selected key search terms. Research quality was assessed using the critical appraisal skills programme tools. The studies were critically appraised by both authors independently, and data were extracted. Four themes addressing the research question were identified and critically evaluated.

FINDINGS

Six primary research articles that investigated different methods of chronotherapy were identified, and the results suggest that multi-component non-pharmacological interventions are the most effective for reducing the prevalence of delirium in critical care. The melatonergic agonist Ramelteon demonstrated statistically significant reductions in delirium; however, the reliability of the results in answering the review question was limited by the research design. The use of bright light therapy (BLT) and dynamic light application had mixed results, with issues with the research design and outcomes measured limiting the validity of the findings.

CONCLUSION

Multi-component non-pharmacological interventions, such as noise and light control, can reduce delirium in critical care, whereas other interventions, such as BLT, have mixed outcomes. Melatonin, as a drug, may be a useful alternative to sedative-hypnotics.

RELEVANCE TO CLINICAL PRACTICE

Chronotherapy can reduce the incidence of delirium within critical care, although further research is warranted. Staff education is essential in the implementation of chronotherapy.

Postoperative confusion in older adults

The development of postoperative confusion in older patients is increasingly being recognized as clinically significant because it is becoming more common as the population ages. Postoperative delirium and postoperative cognitive dysfunction differ in time course of development. Risk factors other than age include certain medications as well as anesthesia (both the type and amount used). Postoperative delirium and postoperative cognitive dysfunction appear to increase a patient's risk for developing dementia. Routine preoperative screening may help to identify patients with preexisting cognitive impairment who are at greatest risk for developing postoperative delirium or postoperative cognitive dysfunction.

'In a dark place, we find ourselves': light intensity in critical care units

Intensive care units provide specialised care for critically ill patients around the clock. However, intensive care unit patients have disrupted circadian rhythms. Furthermore, disrupted circadian rhythms are associated with worse outcome. As light is the most powerful ‘re-setter’ of circadian rhythm, we measured light intensity on intensive care unit. Light intensity was low compared to daylight during the ‘day’; frequent bright light interruptions occurred over ‘night’. These findings are predicted to disrupt circadian rhythms and impair entrainment to external time. Bright lighting during daytime and black out masks at night might help maintain biological rhythms in critically ill patients and improve clinical outcomes.