Mild cognitive impairment with associated inflammatory and cortisol alterations as independent risk factor for postoperative delirium

The utility of the Montreal cognitive assessment (MoCA) in detecting cognitive impairment in surgical populations - A systematic review and meta-analysis

STUDY OBJECTIVE

To determine the diagnostic accuracy of the Montreal Cognitive Assessment (MoCA) in detecting cognitive impairment (CI) and assess the association of MoCA scores with adverse postoperative outcomes in surgical populations.

DESIGN

Systematic review and meta-analysis.

SETTING

Perioperative setting.

PATIENTS

Adults undergoing elective or emergent surgery screened for CI preoperatively using the MoCA.

MEASUREMENTS

The outcomes included the diagnostic accuracy of the MoCA in screening for CI and the pooled prevalence of CI in various surgical populations. CI and its association with adverse events including delirium, hospital length-of-stay (LOS), postoperative complications, discharge destination, and mortality was determined.

MAIN RESULTS

Twenty-six studies (5059 patients, 18 non-cardiac studies, 8 cardiac studies) were included. With a MoCA cut-off score of <26, the prevalence of preoperative CI was 48% (95% CI: 41%-54%). The MoCA had 0.87 (95% CI: 0.79-0.93) sensitivity, 0.72 (95% CI: 0.62-0.80) specificity, PPV of 0.74 (95% CI: 0.65-0.81), and NPV of 0.86 (95% CI: 0.77-0.92) when validated against Petersen criteria, the Diagnostic and Statistical Manual of Mental Disorders, or the National Institute on Aging and the Alzheimer's Association criteria to identify CI. Using the MoCA as a screening tool, the LOS was 3.75 (95% CI: -0.03-7.53, P = 0.05, not significant) days longer in the CI group after non-cardiac surgeries and 3.33 (95% CI: 1.24-5.41, P < 0.002) days longer after cardiac surgeries than the non-cognitively impaired group.

CONCLUSIONS

MoCA had been validated in the surgical population. MoCA with a cut-off score of <26 was shown to have 87% sensitivity and 72% specificity in identifying CI. A positive screen in MoCA was associated with a 3-day longer hospital LOS in cardiac surgery in the CI group than in the non-CI group.

Role of hypoxia-inducible factor in postoperative delirium of aged patients: A review

Postoperative delirium is common, especially in older patients. Delirium is associated with prolonged hospitalization, an increased risk of postoperative complications, and significant mortality. The mechanism of postoperative delirium is not yet clear. Cerebral desaturation occurred during the maintenance period of general anesthesia and was one of the independent risk factors for postoperative delirium, especially in the elderly. Hypoxia stimulates the expression of hypoxia-inducible factor-1 (HIF-1), which controls the hypoxic response. HIF-1 may have a protective role in regulating neuron apoptosis in neonatal hypoxia-ischemia brain damage and may promote the repair and rebuilding process in the brain that was damaged by hypoxia and ischemia. HIF-1 has a neuroprotective effect during cerebral hypoxia and controls the hypoxic response by regulating multiple pathways, such as glucose metabolism, angiogenesis, erythropoiesis, and cell survival. On the other hand, anesthetics have been reported to inhibit HIF activity in older patients. So, we speculate that HIF plays an important role in the pathophysiology of postoperative delirium in the elderly. The activity of HIF is reduced by anesthetics, leading to the inhibition of brain protection in a hypoxic state. This review summarizes the possible mechanism of HIF participating in postoperative delirium in elderly patients and provides ideas for finding targets to prevent or treat postoperative delirium in elderly patients.

Meta-analysis of serological biomarkers at hospital admission for the likelihood of developing delirium during hospitalization

Importance

Identifying biomarkers that, at hospital admission, predict subsequent delirium will help to focus our clinical efforts on prevention and management.

Objective

The study aimed to investigate biomarkers at hospital admission that may be associated with delirium during hospitalization.

Data sources

A librarian at the Fraser Health Authority Health Sciences Library performed searches from 28 June 2021 to 9 July 2021, using the following sources: Medline, EMBASE, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Cochrane Methodology Register, and the Database of Abstracts of Reviews and Effects.

Study selection

The inclusion criteria were articles in English that investigated the link between serum concentration of biomarkers at hospital admission and delirium during hospitalization. Exclusion criteria were single case reports, case series, comments, editorials, letters to the editor, articles that were not relevant to the review objective, and articles concerning pediatrics. After excluding duplicates, 55 studies were included.

Data extraction and synthesis

This meta-analysis followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) protocol. Independent extraction, with the consensus of multiple reviewers, was used to determine the final studies included. The weight and heterogeneity of the manuscripts were calculated using inverse covariance with a random-effects model.

Main outcomes and measures

Differences in mean serum concentration of biomarkers at hospital admission between patients who did and did not develop delirium during hospitalization.

Results

Our search found evidence that patients who developed delirium during hospitalization had, at hospital admission, significantly greater concentrations of certain inflammatory biomarkers and one blood-brain barrier leakage marker than patients who did not develop delirium during hospitalization (differences in the mean: cortisol: 3.36 ng/ml, p < 0.0001; CRP: 41.39 mg/L, p < 0.00001; IL-6: 24.05 pg/ml, p < 0.00001; S100β 0.07 ng/ml, p < 0.00001). These differences were independent of other confounding variables such as the patient's severity of illness. A significantly lower serum concentration, at hospital admission, of acetylcholinesterase (difference in the means -0.86 U/ml, p = 0.004) was also associated with an increased vulnerability to developing delirium during hospitalization.

Conclusion and relevance

Our meta-analysis supports the hypothesis that patients with hypothalamic-pituitary axis dysfunction, increased blood-brain barrier permeability, and chronic overload of the cholinergic system, at hospital admission, are more vulnerable to developing delirium during hospitalization.

The possible role of gut microbiota dysbiosis in the pathophysiology of delirium in older persons

Delirium is a clinical syndrome characterized by an acute change in attention, awareness and cognition with fluctuating course, frequently observed in older patients during hospitalization for acute medical illness or after surgery. Its pathogenesis is multifactorial and still not completely understood, but there is general consensus on the fact that it results from the interaction between an underlying predisposition, such as neurodegenerative diseases, and an acute stressor acting as a trigger, such as infection or anesthesia. Alterations in brain insulin sensitivity and metabolic function, increased blood-brain barrier permeability, neurotransmitter imbalances, abnormal microglial activation and neuroinflammation have all been involved in the pathophysiology of delirium. Interestingly, all these mechanisms can be regulated by the gut microbiota, as demonstrated in experimental studies investigating the microbiota-gut-brain axis in dementia. Aging is also associated with profound changes in gut microbiota composition and functions, which can influence several aspects of disease pathophysiology in the host. This review provides an overview of the emerging evidence linking age-related gut microbiota dysbiosis with delirium, opening new perspectives for the microbiota as a possible target of interventions aimed at delirium prevention and treatment.

Postoperative Outcomes in Elderly Patients Undergoing Cardiac Surgery With Preoperative Cognitive Impairment: A Systematic Review and Meta-Analysis

BACKGROUND

Older patients with preoperative cognitive impairment are at risk for increased postoperative complications after noncardiac surgery. This systematic review and meta-analysis aimed to determine the association between preoperative cognitive impairment and dementia and postoperative outcomes in older surgical patients after cardiac surgery.

METHODS

Eight electronic databases were searched from inception to January 4, 2022. Inclusion criteria were cardiac surgery patients ≥60 years of age; preoperative cognitive impairment; ≥1 postoperative complication reported; comparator group with no preoperative cognitive impairment; and written in English. Using a random-effects model, we calculated effect sizes as odds ratio (OR) and standardized mean differences (SMDs). Risk of random error was assessed by applying trial sequential analysis.

RESULTS

Sixteen studies (62,179 patients) were included. Preoperative cognitive impairment was associated with increased risk of delirium in older patients after cardiac surgery (70.0% vs 20.5%; OR, 8.35; 95% confidence interval [CI], 4.25-16.38; I2, 0%; P < .00001). Cognitive impairment was associated with increased hospital length of stay (LOS; SMD, 0.36; 95% CI, 0.20-0.51; I2, 22%; P < .00001) and intensive care unit (ICU) LOS (SMD, 0.39; 95% CI, 0.09-0.68; I2, 70%; P = .01). No significant association was seen for 30-day mortality (1.7% vs 1.1%; OR, 2.58; 95% CI, 0.64-10.44; I2, 55%; P = .18).

CONCLUSIONS

In older patients undergoing cardiac surgery, cognitive impairment was associated with an 8-fold increased risk of delirium, a 5% increase in absolute risk of major postoperative bleeding, and an increase in hospital and ICU LOS by approximately 0.4 days. Further research on the feasibility of implementing routine neurocognitive testing is warranted.

Predisposing and Precipitating Factors Associated With Delirium: A Systematic Review

IMPORTANCE

Despite discrete etiologies leading to delirium, it is treated as a common end point in hospital and in clinical trials, and delirium research may be hampered by the attempt to treat all instances of delirium similarly, leaving delirium management as an unmet need. An individualized approach based on unique patterns of delirium pathophysiology, as reflected in predisposing factors and precipitants, may be necessary, but there exists no accepted method of grouping delirium into distinct etiologic subgroups.

OBJECTIVE

To conduct a systematic review to identify potential predisposing and precipitating factors associated with delirium in adult patients agnostic to setting.

EVIDENCE REVIEW

A literature search was performed of PubMed, Embase, Web of Science, and PsycINFO from database inception to December 2021 using search Medical Subject Headings (MeSH) terms consciousness disorders, confusion, causality, and disease susceptibility, with constraints of cohort or case-control studies. Two reviewers selected studies that met the following criteria for inclusion: published in English, prospective cohort or case-control study, at least 50 participants, delirium assessment in person by a physician or trained research personnel using a reference standard, and results including a multivariable model to identify independent factors associated with delirium.

FINDINGS

A total of 315 studies were included with a mean (SD) Newcastle-Ottawa Scale score of 8.3 (0.8) out of 9. Across 101 144 patients (50 006 [50.0%] male and 49 766 [49.1%] female patients) represented (24 015 with delirium), studies reported 33 predisposing and 112 precipitating factors associated with delirium. There was a diversity of factors associated with delirium, with substantial physiological heterogeneity.

CONCLUSIONS AND RELEVANCE

In this systematic review, a comprehensive list of potential predisposing and precipitating factors associated with delirium was found across all clinical settings. These findings may be used to inform more precise study of delirium's heterogeneous pathophysiology and treatment.

Increased postoperative myeloperoxidase concentration associated with low baseline antioxidant capacity as the risk factor of delirium after cardiac surgery

BACKGROUND

Though risk factors of postoperative delirium are well described, its pathophysiology is still undiscovered. The primary objective of the current study is to assess whether increased pre- and postoperative myeloperoxidase (MPO) levels are associated with postoperative delirium in the population of cardiac surgery patients. The secondary objective is to evaluate the correlation between MPO levels and serum antioxidant capacity (AC).

METHODS

The patients' cognitive status was assessed one day preoperatively with the use of the Mini-Mental State Examination Test and the Clock Drawing Test. A diagnosis of major depressive disorder and anxiety disorders was established based on DSM-5 criteria. Blood samples for MPO and AC levels were collected both pre- and postoperatively. The Confusion Assessment Method for the Intensive Care Unit was used to screen for a diagnosis of delirium.

RESULTS

Delirium occurred in 34% (61 of 177) of patients. Multivariable logistic regression analysis revealed that increased postoperative MPO concentration was independently associated with postoperative delirium development, and negatively correlated with lower baseline serum AC.

CONCLUSIONS

Cardiac surgery patients with less efficient antioxidative mechanisms experience a higher postoperative peak of serum MPO, which in turn may predispose to postoperative delirium development.KEY MESSAGESMPO is a lysosomal enzyme with strong pro-oxidative and pro-inflammatory properties.Cardiac surgery patients who have increased concentration of postoperative MPO are at significantly higher risk of postoperative delirium development.This higher level of postoperative MPO is negatively correlated with baseline antioxidant capacity (AC).It can be hypothesized that individuals with decreased baseline AC experience a higher peak of MPO post-surgery due to less efficient antioxidative mechanisms, which in turn contributes to postoperative delirium development.

Thyroid hormone, cortisol, interleukin-2, and procalcitonin regulate postoperative delirium in acute type A aortic dissection patients

BACKGROUND

We assessed the relationships between levels of preoperative thyroid hormone (TH), cortisol, interleukin-2 (IL-2), and procalcitonin (PCT) and postoperative delirium (POD) in acute type A aortic dissection (ATAAD) patients receiving modified triple-branched stent-graft (MTBSG) implant surgeries.

METHODS

ATAAD patients received MTBSG implant surgeries in our hospital between February 2019 and December 2020 were recruited. We separated them into a POD and non-POD cohort and employed univariable and multivariable regression analysis to establish independent correlations between preoperative THs, cortisol, IL-2, and PCT and POD. In addition, we conducted stratification analyses to examine the link between pre-surgical THs and POD in normal TSH and lower TSH subgroups.

RESULTS

POD occurred in 78 of 224 patients (34.8%). POD patients exhibited markedly reduced preoperative free triiodothyronine (FT3) (P = 0.008) and free thyroxine (FT4) (P = 0.023) levels, while remarkably enhanced preoperative cortisol (P < 0.001), IL-2 (P < 0.001), and PCT (P < 0.001) levels. Based on multivariate regression analysis, reduced preoperative FT3 (P = 0.032), as well as augmented preoperative IL-2 (P = 0.001), cortisol (P < 0.001), and PCT (P = 0.016) were strong stand-alone risk factors for POD. Moreover, subgroup analysis found the association between FT3 (P = 0.029), FT4 (P = 0.042) and POD was both significant in patients with normal TSH levels.

CONCLUSIONS

Reduced preoperative FT3 and elevated preoperative cortisol, IL-2, and PCT were strong indicators of POD in ATAAD patients. Hence, we recommend that the thyroid function, cortisol, PCT, and IL-2 should be evaluated prior to surgery in ATAAD patients.

Lower Preoperative Verbal Memory Performance Is Associated with Delirium after Coronary Artery Bypass Graft Surgery: A Prospective Cohort Study

OBJECTIVE

Cognitive impairment constitutes one of the major risk factors of delirium after coronary artery bypass graft (CABG) surgery; however, it is unclear whether only patients with global cognitive decline are at increased risk for delirium or if individuals with preserved global cognitive functions but impairments in specific cognitive domains are also more vulnerable to developing delirium. Thus, this study aimed to analyze the neurocognitive status of patients scheduled for CABG surgery with the use of an advanced computerized cognitive battery (CNS Vital Signs) and to investigate possible associations between impaired performance in selective cognitive areas and the risk of postoperative delirium development.

METHODS

The study enrolled 127 participants with a median age of 67 years (IQR: 63-71). Postoperative delirium developed in 32 (25%) patients.Before surgery, the patients were screened for global cognitive impairment with the use of the Mini-Mental State Examination Test, and the individuals were asked to perform the CNS Vital Signs battery to investigate 12 specific cognitive domains. The Confusion Assessment Method and the Memorial Delirium Assessment Scale were used to screen for a diagnosis of delirium postoperatively.

RESULTS

In multivariate models, a lower score of verbal memory-assessed preoperatively was independently associated with the risk of postoperative delirium development. Other independent predictors of delirium included more advanced age, gender female, depression, postoperative pyrexia, and the presence of extracorporeal circulation.

CONCLUSIONS

As decreased verbal memory constitutes an independent risk factor for postoperative delirium, a verbal memory test may be a useful predictor of postoperative delirium development.

The effects of dexmedetomidine on the cognitive function of mild cognitive impairment (MCI) rats

Background

The study sought to investigate the effects of dexmedetomidine (DEX) on cognitive function after anesthesia and to examine its actual mechanism.

Methods

A total of 48 rats were injected with d-galactose (D-gal) 1,000 mg·kg⁻¹·d⁻¹ and normal saline at the neck and back for 1 week to establish rats with mild cognitive impairment (MCI) and conduct behavioral tests. Sevoflurane was inhaled and DEX was pumped into each group respectively. Morris water maze (MWM) test was conducted 24 hours later. The inflammatory factors interleukin (IL)-1, interleukin (IL)-6, and a tumor necrosis factor (TNF)-α in brain homogenate were quantitatively measured by enzyme-linked immunosorbent assay (ELISA) on the next day. The apoptosis of hippocampal cells was observed by hematoxylin-eosin staining (HE staining).

Results

In relation to the model establishment, we found that there was no significant difference in body weight and swimming speed before and after modeling. There was no statistically significant difference in the escape latency between Groups A, B, C, and D before modeling. After modeling, there was no statistical difference in the escape latency between Groups A, B, and C, but the difference was statistically significant when compared to Group D (P<0.05). In relation to the DEX intervention, we found that compared to Group C, MWM test performance in Groups A and B was considerably worse longer escape latencies and fewer platform crossings within 90 seconds), and were more significant in Group A. Compared with Group D, the levels of inflammatory cytokines of the brain homogenates were elevated, and this elevation was highest in Group A, followed by Group B; the pathological changes were consistent with changes in behavioral tests. In Group A, there were obvious disorders of glial cell arrangement, apoptosis and deletion. There was no significant change in Group D. And the changes of vertebral cells in Group B and Group C were slight, with orderly arrangement and intact cell structure.

Conclusions

DEX inhibits the apoptosis of hippocampal cells and reduces the cognitive dysfunction of rats with MCI induced by D-gal via the inhibition of the release of inflammatory cytokines.

Postoperative delirium and its relationship with biomarkers for dementia: a meta-analysis

OBJECTIVES

This study seeks to identify Alzheimer's and related dementias (ADRD) biomarkers associated with postoperative delirium (POD) via meta-analysis.

DESIGN

A comprehensive search was conducted. Studies met the following inclusion criteria: >18 years of age, identified POD with standardized assessment, and biomarker measured in the AT(N)-X (A = amyloid, T = tau, (N)=neurodegeneration, X-Other) framework. Exclusion criteria: focus on prediction of delirium, delirium superimposed on dementia, other neurologic or psychiatric disorders, or terminal delirium. Reviewers extracted and synthesized data for the meta-analysis.

SETTING

Meta-analysis.

PARTICIPANTS

Patients with POD.

MEASUREMENTS

Primary outcome: association between POD and ATN-X biomarkers. Secondary outcomes involved sample heterogeneity.

RESULTS

28 studies were included in this meta-analysis. Studies focused on inflammatory and neuronal injury biomarkers; there were an insufficient number of studies for amyloid and tau biomarker analysis. Two inflammatory biomarkers (IL-6, and CRP) showed a significant relationship with POD (IL-6 n = 10, standardized mean difference (SMD): 0.53, 95% CI: 0.36-0.70; CRP n = 14, SMD: 0.53, 95% CI: 0.33-0.74). Two neuronal injury biomarkers (blood-based S100B and NfL) were positively associated with POD (S100B n = 5, SMD: 0.40, 95% CI: 0.11-0.69; NFL n = 2, SMD: 0.93, 95% CI: 0.28-1.57). Of note, many analyses were impacted by significant study heterogeneity.

CONCLUSIONS

This meta-analysis identified an association between certain inflammatory and neuronal injury biomarkers and POD. Future studies will need to corroborate these relationships and include amyloid and tau biomarkers in order to better understand the relationship between POD and ADRD.

Oxidative stress and soluble receptor for advanced glycation end-products play a role in the pathophysiology of delirium after cardiac surgery

Coronary-artery bypass graft (CABG) surgery is known to improve cardiac function and decrease mortality, albeit, this method of treatment is also associated with a neuropsychiatric complications including postoperative delirium. The pathophysiology of delirium after cardiac surgery remains poorly understood. Thus, the purpose of this study was to investigate whether oxidative stress reflected by decreased preoperative and postoperative plasma antioxidant activity is independently associated with delirium after cardiac surgery. The second aim was to assess whether decreased antioxidant activity is stress-related or mediated by other pathologies such as major depressive disorder (MDD), anxiety disorders, and cognitive impairment. Furthermore, the putative relationship between pre- and postoperative soluble receptor for advanced glycation end-products (sRAGE) overexpression and plasma antioxidant capacity was evaluated. The patients cognitive status was assessed 1 day preoperatively with the use of the Mini-Mental State Examination Test and the Clock Drawing Test. A diagnosis of MDD and anxiety disorders was established on the basis of DSM-5 criteria. Blood samples for antioxidant capacity and sRAGE levels were collected both preoperatively and postoperatively. The Confusion Assessment Method for the Intensive Care Unit was used within the first 5 days postoperatively to screen for a diagnosis of delirium. Postoperative delirium was diagnosed in 34% (61 of 177) of individuals. Multivariate logistic regression analysis revealed that low baseline antioxidant capacity was independently associated with postoperative delirium development. Moreover, increased risk of delirium was observed among patients with a preoperative diagnosis of MDD associated with antioxidant capacity decreased postoperatively. According to receiver operating characteristic analysis, the most optimal cutoff values of the preoperative and postoperative antioxidant capacity that predict the development of delirium were 1.72 mM and 1.89 mM, respectively. Pre- and postoperative antioxidant capacity levels were negatively correlated with postoperative sRAGE concentration (Spearman's Rank Correlation − 0.198 and − 0.158, p < 0.05, respectively). Patients with decreased preoperative antioxidant activity and those with depressive episodes complicated with lower postoperative antioxidant activity are at significantly higher risk of delirium after cardiac surgery development. sRAGE overexpression may be considered as protective mechanism against increased oxidative stress and subsequent cell damage.

Automated machine learning-based model predicts postoperative delirium using readily extractable perioperative collected electronic data

Objective

Postoperative delirium (POD) is a common postoperative complication that is relevant to poor outcomes. Therefore, it is critical to find effective methods to identify patients with high risk of POD rapidly. Creating a fully automated score based on an automated machine‐learning algorithm may be a method to predict the incidence of POD quickly.

Materials and methods

This is the secondary analysis of an observational study, including 531 surgical patients who underwent general anesthesia. The least absolute shrinkage and selection operator (LASSO) was used to screen essential features associated with POD. Finally, eight features (age, intraoperative blood loss, anesthesia duration, extubation time, intensive care unit [ICU] admission, mini‐mental state examination score [MMSE], Charlson comorbidity index [CCI], postoperative neutrophil‐to‐lymphocyte ratio [NLR]) were used to established models. Four models, logistic regression, random forest, extreme gradient boosted trees, and support vector machines, were built in a training set (70% of participants) and evaluated in the remaining testing sample (30% of participants). Multivariate logistic regression analysis was used to explore independent risk factors for POD further.

Results

Model 1 (logistic regression model) was found to outperform other classifier models in testing data (area under the curve [AUC] of 80.44%, 95% confidence interval [CI] 72.24%–88.64%) and achieve the lowest Brier Score as well. These variables including age (OR = 1.054, 95%CI: 1.017~1.093), extubation time (OR = 1.027, 95%CI: 1.012~1.044), ICU admission (OR = 2.238, 95%CI: 1.313~3.793), MMSE (OR = 0.929, 95%CI: 0.876~0.984), CCI (OR = 1.197, 95%CI: 1.038~1.384), and postoperative NLR (OR = 1.029, 95%CI: 1.002~1.057) were independent risk factors for POD in this study.

Conclusions

We have built and validated a high‐performing algorithm to demonstrate the extent to which patient risk changes of POD during the perioperative period, thus leading to a rational therapeutic choice.

Preoperative Cerebrospinal Fluid Cortisol and the Risk of Postoperative Delirium: A Prospective Study of Older Hip Fracture Patients

BACKGROUND

Ageing, depression, and neurodegenerative disease are common risk factors for delirium in the elderly. These risk factors are associated with dysregulation of the hypothalamic-pituitary-adrenal axis, resulting in higher levels of cortisol under normal and stressed conditions and a slower return to baseline.

OBJECTIVES

We investigated whether elevated preoperative cerebrospinal fluid (CSF) cortisol levels are associated with the onset of postoperative delirium.

METHODS

In a prospective cohort study CSF samples were collected after cannulation for the introduction of spinal anesthesia of 75 patients aged 75 years and older admitted for surgical repair of acute hip fracture. Delirium was assessed with the confusion assessment method (CAM) and the Delirium Rating Scale-Revised-98 (DRS-R98). Because the CAM and DRS-R98 were available for time of admission and 5 postoperative days, we used generalized estimating equations and linear mixed modeling to examine the association between preoperative CSF cortisol levels and the onset of postoperative delirium.

RESULTS

Mean age was 83.5 (SD 5.06) years, and prefracture cognitive decline was present in one-third of the patients (24 [33%]). Postoperative delirium developed in 27 (36%) patients. We found no association between preoperative CSF cortisol levels and onset or severity of postoperative delirium.

CONCLUSIONS

These findings do not support the hypothesis that higher preoperative CSF cortisol levels are associated with the onset of postoperative delirium in elderly hip fracture patients.

Glucocorticoids and the Brain after Critical Illness

Treatment for critical illness typically focuses on a patient's short-term physical recovery; however, recent work has broadened our understanding of the long-term implications of illness and treatment strategies. In particular, survivors of critical illness have significantly elevated risk of developing lasting cognitive impairment and psychiatric disorders. In this review, we examine the role of endogenous and exogenous glucocorticoids in neuropsychiatric outcomes following critical illness. Illness is marked by acute elevation of free cortisol and adrenocorticotropic hormone suppression, which typically normalize after recovery; however, prolonged dysregulation can sometimes occur. High glucocorticoid levels can cause lasting alterations to the plasticity and structural integrity of the hippocampus and prefrontal cortex, and this mechanism may plausibly contribute to impaired memory and cognition in critical illness survivors, though specific evidence is lacking. Glucocorticoids may also exacerbate inflammation-associated neural damage. Conversely, current evidence indicates that glucocorticoids during illness may protect against the development of post-traumatic stress disorder. We propose future directions for research in this field, including determining the role of persistent glucocorticoid elevations after illness in neuropsychiatric outcomes, the role of systemic vs neuroinflammation, and probing unexplored lines of investigation on the role of mineralocorticoid receptors and the gut-brain axis. Progress toward personalized medicine in this area has the potential to produce tangible improvements to the lives patients after a critical illness, including Coronavirus Disease 2019.

Intraoperative dexmedetomidine for prevention of postoperative delirium in elderly patients with mild cognitive impairment

OBJECTIVES

Delirium is the most common postoperative neurological complication and some evidence suggests that dexmedetomidine is associated with a decreased incidence of delirium. This study is designed to assess the effect of dexmedetomidine on postoperative delirium (POD) in elderly patients with mild cognitive impairment (MCI).

METHODS

Sixty geriatric patients with MCI were enrolled and ramdomly divided into two groups by a computer-generated randomisation sequence: dexmedetomidine group (D group) and normal saline group (C group). Patients in D group received a loading dose of 0.5 μg/kg dexmedetomidine over 10 minutes before anesthesia induction, followed by a continuous infusion of 0.4 μg·kg^-1·h^-1 until 30 minutes before the end of surgery; equal volume of normal saline was given in C group. Blood samples were extracted to detect the concentration of cytokines, including tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), heme oxygenase-1 (HO-1), matrix metalloproteinase-9 (MMP-9), and glial fibrillary acidic protein (GFAP) before anesthesia induction (T₁), before suture (T₂), and 30 minutes after surgery (T₃). Postoperative recovery times were recorded. Delirium was assessed with the 3-Minute Diagnostic Interview for confusion assessment method during the first 7 days postoperatively.

RESULTS

POD occurred in 10 (33.3%) of 30 patients in C group, and in 3 (10%) of 30 patients given dexmedetomidine (odds ratio [OR] 0.222, 95% CI 0.054-0.914; P = 0.028). The serum concentrations of TNF-α, MMP-9, and GFAP were significantly increased and IL-10 was decreased in the C group than in the D group at T₂ and T₃. No differences were observed between groups in the level of HO-1. Analysis using random-effect multivariable logistic regression indicated that POD was associated with GFAP (odds ratio [OR] 16.691, 95% CI 2.288-121.746; P = 0.005). The positive predictive ability of the multivariate logistic regression model tested by ROC analysis showed an area under the curve of 0.713 (95% CI, 0.584-0.842).

CONCLUSIONS

Dexmedetomidine can alleviate POD in elderly patients with MCI and may be related to reduce the neuroinflammation by lowering the permeability of blood-brain barrier.

A short delirium caregiver questionnaire for triage of elderly outpatients with cognitive impairment: a development and test accuracy study

OBJECTIVES

Delirium is often missed in older outpatients. Caregivers can give valuable information that might improve identification rates. The aim of this study was to develop a short and sensitive delirium caregiver questionnaire (DCQ) for triage of elderly outpatients with cognitive impairment by telephone.

DESIGN, SETTING, AND PARTICIPANTS

The pilot questionnaire was administered to 112 caregivers of patients who were referred for dementia screening to our clinic for geriatric psychiatry, and the final DCQ to 234 other caregivers.

MEASUREMENTS

In phase I (2013-2014), we tested a pilot questionnaire with 17 items. Health professionals who established delirium diagnoses were blinded to the results. We then used the results and other information available at referral to construct the final DCQ with seven items. During phase II (2015-2016), we investigated the test accuracy of the final DCQ in a subsequent cohort. In both phases, the patients received a structured diagnostic workup. Time between referral and first visit was a secondary outcome.

RESULTS

The final DCQ consisted of the following items: emergency visit required, sleeping disorder, fluctuating course, hallucinations, suspicious thoughts, previous delirium, and recent discharge from hospital. DCQ results indicated that urgent intake was required in 85 of 234 patients. Sensitivity was 73.5% (95% CI: 58.9-85.1%) and specificity 73.5% (95% CI: 66.5-79.7%). The mean number of days to first visit dropped from 31.6 to 11.2 in delirious patients (p = 0.001).

CONCLUSIONS

Triage with the easy-to-use DCQ among patients referred for cognitive screening leads to earlier assessment and higher detection rates of delirium.

Risk Factors for Delirium and Cognitive Decline Following Coronary Artery Bypass Grafting Surgery: A Systematic Review and Meta-Analysis

Background

Coronary artery bypass grafting (CABG) is known to improve heart function and quality of life, while rates of surgery‐related mortality are low. However, delirium and cognitive decline are common complications. We sought to identify preoperative, intraoperative, and postoperative risk or protective factors associated with delirium and cognitive decline (across time) in patients undergoing CABG.

Methods and Results

We conducted a systematic search of Medline, PsycINFO, EMBASE, and Cochrane (March 26, 2019) for peer‐reviewed, English publications reporting post‐CABG delirium or cognitive decline data, for at least one risk factor. Random‐effects meta‐analyses estimated pooled odds ratio for categorical data and mean difference or standardized mean difference for continuous data. Ninety‐seven studies, comprising data from 60 479 patients who underwent CABG, were included. Moderate to large and statistically significant risk factors for delirium were as follows: (1) preoperative cognitive impairment, depression, stroke history, and higher European System for Cardiac Operative Risk Evaluation (EuroSCORE) score, (2) intraoperative increase in intubation time, and (3) postoperative presence of arrythmia and increased days in the intensive care unit; higher preoperative cognitive performance was protective for delirium. Moderate to large and statistically significant risk factors for acute cognitive decline were as follows: (1) preoperative depression and older age, (2) intraoperative increase in intubation time, and (3) postoperative presence of delirium and increased days in the intensive care unit. Presence of depression preoperatively was a moderate risk factor for midterm (1–6 months) post‐CABG cognitive decline.

Conclusions

This meta‐analysis identified several key risk factors for delirium and cognitive decline following CABG, most of which are nonmodifiable. Future research should target preoperative risk factors, such as depression or cognitive impairment, which are potentially modifiable.

Registration

URL: https://www.crd.york.ac.uk/prosp​ero/; Unique identifier: CRD42020149276.

Methylene blue reduces incidence of early postoperative cognitive disorders in elderly patients undergoing major non-cardiac surgery: An open-label randomized controlled clinical trial

STUDY OBJECTIVE

The purpose of the present study was to investigate whether methylene blue (MB) could reduce the incidences of postoperative delirium (POD) and early postoperative cognitive dysfunction (POCD) in elderly patients undergoing major non-cardiac surgery.

DESIGN

Prospective, randomized, open-label clinical trial.

SETTING

University-affiliated hospital.

PATIENTS

Two hundred and forty-eight elderly patients scheduled for non-cardiac surgery.

INTERVENTIONS

Elderly patients undergoing non-cardiac major surgery were randomly assigned to MB group (n = 124), who receiving intravenous infusion of 2 mg/kg MB within 60 min immediately after anesthetic induction, or control group (n = 124), who receiving equal volume saline in the same way.

MEASUREMENTS

All patients were evaluated with delirium and neuropsychological batteries before and after surgery, as well as perioperative adverse events. Two plasma biomarkers superoxide dismutase (SOD) and homocysteine (HCY) were measured pre- and post-operatively.

MAIN RESULTS

There were total 39 cases(15.7%)experienced POD. The incidence of POD in MB group was significantly less than that in control group (7.3% vs. 24.2%, OR = 0.24, 95%CI: 0.11-0.53, p < 0.001). The incidence of early POCD at postoperative 7th day in MB group was also less than that in control group (16.1% vs. 40.2%, OR = 0.30, 95% CI: 0.16-0.57, p < 0.001). The adverse events were comparable in both groups. In addition, there was no significant correlation between POD/POCD and levels of SOD or HCY.

CONCLUSION

We conclude that intraoperative intravenous 2 mg/kg MB could significantly reduce the incidences of POD and early POCD in elderly surgical patients, while not remarkably increase incidence of perioperative adverse events, suggesting MB may be clinically effective and safe for prevention of early postoperative neurocognitive disorders.

Preoperative Depression and Plasma Cortisol Levels as Predictors of Delirium after Cardiac Surgery

BACKGROUND

Delirium is common in old patients who undergo cardiac surgery, and it is associated with adverse outcomes. The genesis of delirium is thought to be multi-factorial, but it is still not well understood. Symptoms of depression and elevated cortisol level have been described in some previous studies as factors associated with delirium, suggesting a shared pathophysiology.

AIMS

The objective of the present study was to determine whether preoperative depression symptoms and increased cortisol level represent risk factors for delirium after cardiac surgery.

METHODS

We performed a prospective cohort study in 183 patients aged >50 years undergoing elective cardiac surgery. The Geriatric Depression Scale (GDS) was used to assess patients for depressive symptoms before surgery. Preoperative plasma cortisol levels were available in 145 participants. Delirium was diagnosed using the Confusion Assessment Method for Intensive Care Unit (CAM-ICU) during the first 7 days after surgery. Spearman correlation was used for correlations between GDS, Mini-Mental State Examination (MMSE), Charlson comorbidity index, and age. Binary logistic regression was used to determine whether GDS and cortisol levels predict postoperative delirium.

RESULTS

Delirium occurred in 60 patients out of 183 (32.8%) included and lasted 2.3 days (SD 1.36). GDS was correlated with age (p = 0.001) and comorbidity index (p = 0.003) and inversely correlated with MMSE score (p < 0.001). Higher preoperative GDS scores were associated with incidence of delirium in the postoperative period (p = 0.002). The association was significant after controlling for age, MMSE score, history of stroke, and Charlson comorbidity index (p = 0.045). Preoperative cortisol level was not associated with the development of postoperative delirium.

CONCLUSION

Our results suggest that a higher preoperative depression score is associated with an increased risk of postoperative delirium. On the other hand, preoperative plasma cortisol level does not seem to be a predictor of delirium after surgery. Further studies are needed to determine the potential of preoperative depression treatment to prevent postoperative delirium.

Approach to the Older Adult With New Cognitive Symptoms

Dementia affects nearly 50 million people worldwide, translating into one new case every 3 seconds. Dementia syndrome is one of the leading causes of disability among older adults, yet it remains vastly underdiagnosed. A timely diagnosis of dementia is essential to ensuring optimal care and support of individuals and their loved ones. Although there is no single test for dementia, health care providers can use a structured approach to the workup and management of new cognitive symptoms. Comprehensive MEDLINE and PubMed searches were performed to develop an unbiased, practical diagnostic approach to these symptoms. This review guides primary care providers in the workup, diagnosis, delivery, and initial management of patients presenting with new cognitive symptoms.

A systematic review of the overlap of fluid biomarkers in delirium and advanced cancer-related syndromes

BACKGROUND

Delirium is a serious and distressing neurocognitive disorder of physiological aetiology that is common in advanced cancer. Understanding of delirium pathophysiology is largely hypothetical, with some evidence for involvement of inflammatory systems, neurotransmitter alterations and glucose metabolism. To date, there has been limited empirical consideration of the distinction between delirium pathophysiology and that of the underlying disease, for example, cancer where these mechanisms are also common in advanced cancer syndromes such as pain and fatigue. This systematic review explores biomarker overlap in delirium, specific advanced cancer-related syndromes and prediction of cancer prognosis.

METHODS

A systematic review (PROSPERO CRD42017068662) was conducted, using MEDLINE, PubMed, Embase, CINAHL, CENTRAL and Web of Science, to identify body fluid biomarkers in delirium, cancer prognosis and advanced cancer-related syndromes of interest. Studies were excluded if they reported delirium tremens only; did not measure delirium using a validated tool; the sample had less than 75% of participants with advanced cancer; measured tissue, genetic or animal biomarkers, or were conducted post-mortem. Articles were screened for inclusion independently by two authors, and data extraction and an in-depth quality assessment conducted by one author, and checked by two others.

RESULTS

The 151 included studies were conducted in diverse settings in 32 countries between 1985 and 2017, involving 28130 participants with a mean age of 69.3 years. Seventy-one studies investigated delirium biomarkers, and 80 studies investigated biomarkers of an advanced cancer-related syndrome or cancer prognosis. Overall, 41 biomarkers were studied in relation to both delirium and either an advanced cancer-related syndrome or prognosis; and of these, 24 biomarkers were positively associated with either delirium or advanced cancer syndromes/prognosis in at least one study. The quality assessment showed large inconsistency in reporting.

CONCLUSION

There is considerable overlap in the biomarkers in delirium and advanced cancer-related syndromes. Improving the design of delirium biomarker studies and considering appropriate comparator/controls will help to better understanding the discrete pathophysiology of delirium in the context of co-existing illness.

[Research progress of the role of postoperative pain in the development of postoperative cognitive dysfunction in geriatric patients]

Previous studies have shown that postoperative cognitive dysfunction (POCD) is related to multiple factors including age, postoperative trauma, inflammation, postoperative pain, and anesthesia, among which postoperative pain is thought to play an important role in the development of POCD. This review summarizes the recent findings in the study of the role of postoperative pain in the pathogenesis of POCD in light of nerve injuries, neural remodeling and stress, and the progress in the prevention and treatment of POCD in elderly patients. It is of vital important to assess the postoperative pain and formulate adequate analgesic regimens for effective prevention and management of POCD to protect the brain functions of elderly patients.

Effect of flurbiprofen axetil on postoperative delirium for elderly patients

OBJECTIVES

Proinflammatory cytokines triggered by surgery and postoperative pain are major causes of postoperative delirium (POD). This study investigated the effects of flurbiprofen axetil on POD when used for postoperative analgesia after major noncardiac surgery in elderly patients.

METHODS

Patients over 65 years old were randomly divided into two groups: the sufentanil group (S group), in which 150 μg of sufentanil was used in the patient-controlled analgesia (PCA) pump for 3 days; the sufentanil combined with flurbiprofen axetil group (SF group), in which 150 μg of sufentanil was combined with 300 mg of flurbiprofen axetil in the PCA pump for 3 days. The Confusion Assessment Method scale was used for POD evaluation. The pain intensity, side effects, and risk factors (age, gender, surgical position, and category of surgery) for POD were evaluated.

RESULTS

Ultimately, 140 patients were included. The overall incidence of POD was not significantly different between the S and SF groups. The incidence of POD was significantly lower in the SF group than in the S group among patients over 70 years (5.1% vs. 20.7%, p = 0.045, odds ratio = 0.146, 95% confidence interval = 0.020-1.041). The incidence of POD was no difference in patients classified by the category of surgery, surgical position, or gender between groups. Sufentanil and flurbiprofen axetil in the PCA pump was completely used within 72 hr. The pain intensity, consumed sufentanil dosage of the PCA, and the side effects was not different between groups.

CONCLUSIONS

Flurbiprofen axetil might reduce POD in patients over 70 years undergoing major noncardiac surgery.

Penehyclidine hydrochloride on postoperatively cognitive function

There are many drugs that affect postoperative cognitive function in patients under general anesthesia. Pentanethaquine hydrochloride (PHC), as a new type of anti-cholinergic drug, has been widely used. In clinical practice, many patients, especially elderly patients, have suffered from obvious postoperative cognitive dysfunction, but the incidence of pulmonary infection, reduced probably due to the decease of secretion production. Therefore, the effect of PHC on postoperative cognitive functions and inflammatory factors in elderly lung cancer patients under general anesthesia were mainly discussed to determine the clinical advantages and disadvantages. Ninety elderly patients undergoing thoracoscopic surgery for lung cancer under general anesthesia were selected and divided into PHC group (group A, n = 30), atropine group (group B, n = 30) and normal saline control group (group C, n = 30). The incidence of postoperative blurred vision was higher in group A compared to group B and C (both p < 0.05). The incidence of other adverse reactions was higher in group A compared to group C (all p < 0.05), but there was no difference between group A and group B (all p > 0.05). There was no significant difference in preoperative and day 1 post-surgery mini-mental state examination (MMSE) scores among the three groups (both p > 0.05), but the day 1 post-surgery MMSE scores of three groups were lower (all p < 0.05). PHC increased the incidence of postoperative cognitive impairment and postoperative delirium in elderly lung cancer patients undergoing thoracoscopic surgery under general anesthesia, but reduced the incidence of postoperative pulmonary complications possibly by reducing the expression of pro-inflammatory cytokines.

In a Model of Neuroinflammation Designed to Mimic Delirium, Quetiapine Reduces Cortisol Secretion and Preserves Reversal Learning in the Attentional Set Shifting Task

Quetiapine, an atypical antipsychotic medication has lacked pre-clinical validation for its purported benefits in the treatment of delirium. This laboratory investigation examined the effects of quetiapine on the attentional set shifting task (ASST), a measure of cognitive flexibility and executive functioning, in a rodent model of lipopolysaccharide (LPS) mediated neuroinflammation. 19 Sprague Dawley female rats were randomly selected to receive intraperitoneal placebo (N = 5), LPS and placebo (N = 7) or LPS and quetiapine (n = 7) and performed the ASST. We measured trials to criterion, errors, non-locomotion episodes and latency to criterion, serum cortisol and tumor necrosis factor alpha (TNF-α) levels. TNF-α levels were not different between groups at 24 h. Cortisol levels in the LPS + Quetiapine group were reduced compared to LPS + Placebo (P < 0.001) and did not differ from the placebo group (P = 0.15). Analysis between LPS + Quetiapine and LPS + Placebo treated rats demonstrated improvement in the compound discrimination reversal (CD Rev1) (P = 0.016) and the intra-dimensional reversal (ID Rev2) (P = 0.007) discriminations on trials to criterion. LPS + Quetiapine treated rats had fewer errors than LPS + Placebo treated animals in the compound discrimination (CD) (P = 0.007), CD Rev1 (P = 0.005), ID Rev2 (P < 0.001) discriminations. There was no difference in non-locomotion frequency or latency to criterion between the three groups in all discriminations (P > 0.0167). We demonstrated preserved reversal learning, no effect on attentional set shifting and normalized cortisol levels in quetiapine-treated rats in this neuroinflammatory model of delirium. This suggests that quetiapine's beneficial effects in delirium may be related to the preservation of reversal learning and potential downstream effects related to reduction in cortisol production. Graphical Abstract.

Biomarker Predictors of Delirium in Acutely Ill Patients: A Systematic Review

Delirium is a serious and common disorder that affects up to 80% of acutely ill patients, mainly the aged. In recent years, several studies pointed out possible biomarkers that could be used alone or in combination with other resources in the diagnosis and follow-up of critically ill patients who develop delirium. In this context, a systematic review was conducted to determine the predictive value of several biomarkers in acutely (critically and noncritically) ill adult patients with delirium. Studies that used the confusion assessment method (CAM) and CAM-intensive care unit as the diagnostic method were considered. The most recent search was performed in November 2017. There was no language restriction. Initially, 626 articles were screened and 39 were included in the study. A comprehensive evaluation of the abstracts resulted in the exclusion of 202 studies, leaving 39 articles as potentially relevant. Inflammatory markers, S100β and cortisol, could predict delirium occurrence in a specific subgroup population of critically ill patients.

Postoperative cognitive decline: the nurse's role in identifying this underestimated and misinterpreted condition

BACKGROUND

postoperative cognitive changes can increase morbidity and mortality, demand for postoperative care and social and health costs, and can lead to dementia.

AIM

this article discusses perioperative variables that can be used to identify patients who are more vulnerable to experiencing cognitive decline after surgery. It also highlights some screening tools that could be useful for early detection and for planning nursing care.

METHOD

a literature search was conducted using the Medline, CINAHL, PsychINFO and Cochrane Library databases from 2010 to 2018. Google Scholar was also consulted. The reference lists of relevant articles covering postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) were reviewed for further relevant papers.

CONCLUSION

assessment and evaluation of a patient's cognitive resources before and after surgery can lead to clinical interventions to support the person's coping mechanisms; health professionals can reduce the short- and long-term effects of cognitive decline. Screening tools could be used as part of a strategy to minimise postoperative cognitive changes.

Postoperative delirium in critically ill surgical patients: incidence, risk factors, and predictive scores

BACKGROUND

A common postoperative complication found among patients who are critically ill is delirium, which has a high mortality rate. A predictive model is needed to identify high-risk patients in order to apply strategies which will prevent and/or reduce adverse outcomes.

OBJECTIVES

To identify the incidence of, and the risk factors for, postoperative delirium (POD) in surgical intensive care unit (SICU) patients, and to determine predictive scores for the development of POD.

METHODS

This study enrolled adults aged over 18 years who had undergone an operation within the preceding week and who had been admitted to a SICU for a period that was expected to be longer than 24 h. The CAM - ICU score was used to determine the occurrence of delirium.

RESULTS

Of the 250 patients enrolled, delirium was found in 61 (24.4%). The independent risk factors for delirium that were identified by a multivariate analysis comprised age, diabetes mellitus, severity of disease (SOFA score), perioperative use of benzodiazepine, and mechanical ventilation. A predictive score (age + (5 × SOFA) + (15 × Benzodiazepine use) + (20 × DM) + (20 × mechanical ventilation) + (20 × modified IQCODE > 3.42)) was created. The area under the receiver operating characteristic (ROC) curve (AUC) was 0.84 (95% CI: 0.786 to 0.897). The cut point of 125 demonstrated a sensitivity of 72.13% and a specificity of 80.95%, and the hospital mortality rate was significantly greater among the delirious than the non-delirious patients (25% vs. 6%, p < 0.01).

CONCLUSIONS

POD was experienced postoperatively by a quarter of the surgical patients who were critically ill. A risk score utilizing 6 variables was able to predict which patients would develop POD. The identification of high-risk patients following SICU admission can provide a basis for intervention strategies to improve outcomes.

TRIAL REGISTRATION

Thai Clinical Trials Registry TCTR20181204006 . Date registered on December 4, 2018. Retrospectively registered.

Delirium History and Preoperative Mild Neurocognitive Disorder: An Opportunity for Multidisciplinary Patient-Centered Care

Patient: Male, 75

Final Diagnosis: Mild neurocognitive disorder

Symptoms: Apathy • irritability • reduced concentration worsening visual disturbances

Medication: —

Clinical Procedure: Preoperative workup

Specialty: Anesthesiology

Effect of Cognitive Status on the Receipt of Procedures Requiring Anesthesia and Critical Care Admissions in Older Adults

OBJECTIVE

To investigate whether older adults with mild cognitive impairment (MCI) or dementia have higher rates of procedures requiring general anesthesia or intensive care unit (ICU) admissions compared with cognitively normal (CN) patients.

PATIENTS AND METHODS

A population-based cohort, 70 to 89 years old at enrollment, underwent clinical and longitudinal neurocognitive testing to identify those with MCI and dementia. We analyzed the effects of cognitive status (CN, MCI, or dementia) at entry into the study from October 1, 2004, through December 31, 2014, on the risk of receiving procedures requiring surgical anesthesia and ICU admission.

RESULTS

Of 2436 participants, 1977 (81%) were CN, 387 (16%) had MCI, and 72 (3%) had dementia. Cognitively impaired individuals were sicker. Compared with CN individuals, the likelihood of receiving a procedure requiring anesthesia was similar in participants with MCI (adjusted hazard ratio [aHR]=0.98; P=.78). Participants with dementia were less likely to receive these procedures (aHR=0.50; P=.02). Compared with CN participants, the likelihood of ICU admission for any indication was increased for those with MCI (aHR=1.24; P=.03) and dementia (aHR=1.59; P=.04). Admissions to the ICU after procedures were not different in patients with either MCI or dementia (aHR=0.96; P=.83 and aHR=1.01; P=.98, respectively).

CONCLUSION

Patients with MCI or dementia are not more likely to undergo surgery, and neither are they more likely to require ICU admission after procedures. An increased rate of nonsurgical ICU admissions requires vigilance to prevent deterioration of nonsurgical diseases that may lead to ICU admissions.

Clinical outcomes in older surgical patients with mild cognitive impairment

INTRODUCTION

Older adults, including those with mild cognitive impairment (MCI), are increasingly undergoing surgery.

METHODS

Relative risks (RRs) of MCI alone or with delirium on adverse outcomes were estimated in an ongoing prospective, observational cohort study of 560 nondemented adults aged ≥70 years.

RESULTS

MCI (n = 61, 11%) was associated with increased RR of delirium (RR = 1.9, P < .001) and delirium severity (RR = 4.6, P < .001). Delirium alone (n = 107), but not MCI alone (n = 34), was associated with multiple adverse outcomes including more major postoperative complication(s) (RR = 2.5, P = .002) and longer length of stay (RR = 2.2, P < .001). Patients with concurrent MCI and delirium (n = 27) were more often discharged to a postacute facility (RR = 1.4, P < .001) and had synergistically increased risk for new impairments in cognitive functioning (RR = 3.6, P < .001).

DISCUSSION

MCI is associated with increased risk of delirium incidence and severity. Patients with delirium and MCI have synergistically elevated risk of developing new difficulties in cognitively demanding tasks.

Systematic review of prediction models for delirium in the older adult inpatient

OBJECTIVE

To identify existing prognostic delirium prediction models and evaluate their validity and statistical methodology in the older adult (≥60 years) acute hospital population.

DESIGN

Systematic review.

DATA SOURCES AND METHODS

PubMed, CINAHL, PsychINFO, SocINFO, Cochrane, Web of Science and Embase were searched from 1 January 1990 to 31 December 2016. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses and CHARMS Statement guided protocol development.

INCLUSION CRITERIA

age >60 years, inpatient, developed/validated a prognostic delirium prediction model.

EXCLUSION CRITERIA

alcohol-related delirium, sample size ≤50. The primary performance measures were calibration and discrimination statistics. Two authors independently conducted search and extracted data. The synthesis of data was done by the first author. Disagreement was resolved by the mentoring author.

RESULTS

The initial search resulted in 7,502 studies. Following full-text review of 192 studies, 33 were excluded based on age criteria (<60 years) and 27 met the defined criteria. Twenty-three delirium prediction models were identified, 14 were externally validated and 3 were internally validated. The following populations were represented: 11 medical, 3 medical/surgical and 13 surgical. The assessment of delirium was often non-systematic, resulting in varied incidence. Fourteen models were externally validated with an area under the receiver operating curve range from 0.52 to 0.94. Limitations in design, data collection methods and model metric reporting statistics were identified.

CONCLUSIONS

Delirium prediction models for older adults show variable and typically inadequate predictive capabilities. Our review highlights the need for development of robust models to predict delirium in older inpatients. We provide recommendations for the development of such models.

Seeking a New Paradigm for Alzheimer's Disease: Considering the Roles of Inflammation, Blood-Brain Barrier Dysfunction, and Prion Disease

There is no effective etiologic treatment for Alzheimer's disease, nor is there a prophylactic medication which delays or prevents its onset. The lack of an accurate paradigm is undoubtedly related to the lack of effective means of prophylaxis and treatment. The current paradigm of beta amyloid in Alzheimer's brains causing cognitive dysfunction must be modified. Despite failed clinical trials, research continues into amyloid-oriented treatments. The persistence of the amyloid hypothesis/paradigm is an example of anchoring and representativeness heuristics described by Kahneman and Tversky in their classic 1974 Science paper. Economic factors also contribute to the persistence of this paradigm. Paradigms impact the scientific process by the following: (1) what is studied; (2) the types of questions that are asked; (3) the structure and nature of the questions; (4) the interpretations of research findings. We review the contribution of inflammation, malfunction of the neurovascular unit, and prion disease to Alzheimer's disease manifestations. Any or all of these are candidates for inclusion into a more accurate, inclusive, and useful new paradigm. By incorporating emerging facts and understanding into a new paradigm, we will enhance our ability to move toward effective prophylaxis and therapy for this tragic disease.

Post-Operative Cognitive Dysfunction: An exploration of the inflammatory hypothesis and novel therapies

Post-Operative Cognitive Dysfunction (POCD) is a highly prevalent condition with significant clinical, social and financial impacts for patients and their communities. The underlying pathophysiology is becoming increasingly understood, with the role of neuroinflammation and oxidative stress secondary to surgery and anaesthesia strongly implicated. This review aims to describe the putative mechanisms by which surgery-induced inflammation produces cognitive sequelae, with a focus on identifying potential novel therapies based upon their ability to modify these pathways.

Alzheimer's-related cortical atrophy is associated with postoperative delirium severity in persons without dementia

Patients with dementia due to Alzheimer's disease (AD) have increased risk of developing delirium. This study investigated the relationship between a magnetic resonance imaging (MRI)-derived biomarker associated with preclinical AD and postoperative delirium. Participants were older adults (≥70 years) without dementia who underwent preoperative MRI and elective surgery. Delirium incidence and severity were evaluated daily during hospitalization. Cortical thickness was averaged across a published set of a priori brain regions to derive a measure known as the "AD signature." Logistic and linear regression was used, respectively, to test whether the AD signature was associated with delirium incidence in the entire sample (N = 145) or with the severity of delirium among those who developed delirium (N = 32). Thinner cortex in the AD signature did not predict incidence of delirium (odds ratio = 1.15, p = 0.38) but was associated with greater delirium severity among those who developed delirium (b = -1.2, p = 0.014). These results suggest that thinner cortices, perhaps reflecting underlying neurodegeneration due to preclinical AD, may serve as a vulnerability factor that increases severity once delirium occurs.

Mild Cognitive Impairment and Risk of Critical Illness

OBJECTIVES

Approximately half of ICU admissions are comprised of patients older than 65 years old. Mild cognitive impairment is a common disorder affecting 10-20% of patients in the same age group. A need exists for exploring mild cognitive impairment and risk of critical illness. As mild cognitive impairment may be a contributor to poorer overall health or be a result of it, we sought to determine whether the presence of mild cognitive impairment independently increases the risk of critical illness admissions.

DESIGN

Data from the Mayo Clinic Study of Aging were analyzed. All study participants underwent prospective comprehensive cognitive testing and expert panel consensus diagnosis of both cognitive function and clinical state at baseline and subsequent visits. Comparisons were made between those with normal cognitive function and mild cognitive impairment regarding baseline health and frequency of critical illness.

SETTING

Single-center population-based cohort out of Olmsted County, MN.

PARTICIPANTS

All individuals 70-89 years old were screened for prospective enrollment in the Mayo Clinic Study of Aging. Patients with preexisting dementia and ICU admission within 3 years of entry to the study were excluded from this analysis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 2,425 patients analyzed from the Mayo Clinic Study of Aging, 1,734 patients (71%) were included in the current study. Clinical factors associated with baseline mild cognitive impairment included age, male gender, stroke, and poorer health self-rating. Using a Cox regression model adjusting for these and a priori variables of baseline health, the presence of mild cognitive impairment remained a significant predictor of ICU admission (hazard ratio, 1.50 [1.15-1.96]; p = 0.003).

CONCLUSIONS AND RELEVANCE

The presence of mild cognitive impairment is independently associated with increased critical illness admission. Further prospective studies are needed to analyze the impact of critical illness on cognitive function.

Preoperative discussion with patients about delirium risk: are we doing enough?

Postoperative delirium is a common complication in the older surgical population, occurring in 10-50 % of cases. It is thought to be more common if an individual is identified as frail. Postoperative delirium is associated with poor outcome including higher mortality rates, prolonged length of hospital stay, increased care needs on discharge and longer term post-traumatic stress disorder. Guidelines from the American Geriatric Society and the National Institute for Health and Care Excellence highlight the importance of risk assessment at the time of the preoperative visit. This enables the perioperative team to plan a care pathway that minimises the risk of delirium occurring postoperatively. Risk assessment also informs a discussion with patient and family regarding their risk, as part of a process of informed patient consent. This is an essential step in conforming to current legal and General Medical Council guidance on the process of consent.

Undiagnosed long-term cognitive impairment in acutely hospitalised older medical patients with delirium: a prospective cohort study

BACKGROUND

delirium and dementia are common in the general hospital, being present in nearly 50% of older unselected admissions to hospital. Cognitive impairment is a risk factor for delirium, but the prevalence of previously undiagnosed cognitive impairment (dementia or mild cognitive impairment) in patients with delirium is unknown.

METHODS

we performed a prospective cohort study of people over 70 years admitted to hospital with delirium to establish the prevalence of previously unrecognised prior cognitive impairment. Delirium was diagnosed at baseline using the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). Mild cognitive impairment and dementia were diagnosed 3 months following recruitment in survivors using the International Working Group on Mild Cognitive Impairment criteria and DSM-IV criteria, respectively.

RESULTS

delirium was identified in 17.9% of older patients, and 82 participants with delirium were assessed at 3 months: 5 (6%) had persistent delirium, 14 (17%) had mild cognitive impairment and 47 (57%) had dementia. In 17 participants with prior dementia and 14 with prior mild cognitive impairment, the diagnosis had been unrecognised, amounting to 31/82 (38%) of all patients with delirium having some form of previously undiagnosed cognitive impairment.

CONCLUSION

given that over 1/3 of older patients with delirium were found to have a previously undiagnosed cognitive impairment, the development and evaluation of services to follow-up and manage patients with delirium are warranted.

Prevalence and risk factors of postoperative delirium in elderly hip fracture patients

Objective

To explore the risk factors associated with postoperative delirium (PD) in elderly patients following total hip arthroplasty (THA) for hip fracture.

Methods

This prospective study enrolled elderly patients (≥ 65 years) with hip fractures who underwent THA under general anaesthesia, and who had a complete set of postoperative observations. Detailed medical history and perioperative characteristics were recorded. During the postoperative period, patients were assessed twice daily for PD using the Confusion Assessment Method.

Results

A total of 572 patients were eligible for inclusion in the study. Of these, 120 patients (21.0%) were diagnosed with PD and 452 patients (79.0%) did not experience PD. Multivariate stepwise logistic regression analyses showed that older age, a history of stroke, lower albumin, higher blood glucose, higher total bilirubin, higher C-reactive protein, longer surgery duration and higher volume of red blood cell transfusions were independent risk factors for PD.

Conclusions

Correcting the modifiable risk factors might help prevent PD. Strategies might include nutritional support, tight blood glucose control, improvement of liver function, preoperative infection control and minimizing surgical injury or blood loss.

Cognitive and functional status predictors of delirium and delirium severity after coronary artery bypass graft surgery: an interim analysis of the Neuropsychiatric Outcomes After Heart Surgery study

BACKGROUND

Cognitive and functional impairment increase risk for post-coronary artery bypass graft (CABG) surgery delirium (PCD), but how much impairment is necessary to increase PCD risk remains unclear.

METHODS

The Neuropsychiatric Outcomes After Heart Surgery (NOAHS) study is a prospective, observational cohort study of participants undergoing elective CABG surgery. Pre-operative cognitive and functional status based on Clinical Dementia Rating (CDR) scale and neuropsychological battery are assessed. We defined mild cognitive impairment (MCI) based on either (1) CDR global score 0.5 (CDR-MCI) or (2) performance 1.5 SD below population means on any cognitive domain on neurocognitive battery (MCI-NC). Delirium was assessed daily post-operative day 2 through discharge using the confusion assessment method (CAM) and delirium index (DI). We investigate whether MCI - either definition - predicts delirium or delirium severity.

RESULTS

So far we have assessed 102 participants (mean age 65.1 ± 9; male: 75%) for PCD. Twenty six participants (25%) have MCI-CDR; 38 (62% of those completing neurocognitive testing) met MCI-NC criteria. Fourteen participants (14%) developed PCD. After adjusting for age, sex, comorbidity, and education, MCI-CDR, MMSE, and Lawton IADL score predicted PCD on logistic regression (OR: 5.6, 0.6, and 1.5, respectively); MCI-NC did not (OR [95% CI]: 11.8 [0.9, 151.4]). Using similarly adjusted linear regression, MCI-CDR, MCI-NC, CDR sum of boxes, MMSE, and Lawton IADL score predicted delirium severity (adjusted R(2): 0.26, 0.13, 0.21, 0.18, and 0.32, respectively).

CONCLUSIONS

MCI predicts post-operative delirium and delirium severity, but MCI definition alters these relationships. Cognitive and functional impairment independently predict post-operative delirium and delirium severity.

Impact of multicomponent, nonpharmacologic interventions on perioperative cortisol and melatonin levels and postoperative delirium in elderly oral cancer patients

OBJECTIVE

To investigate the impact of multicomponent, nonpharmacologic interventions (MNI) on perioperative cortisol and melatonin levels, as well as postoperative delirium (PD), in elderly oral cancer patients.

METHODS

A total of 160 elderly oral cancer patients who underwent tumor resection surgery and completed our investigation were included in this study. The cancer patients were randomly divided into 2 groups: Group U or Group I. During the perioperative period, Group U received usual care, while Group I received MNI, which is based on usual care and aims to decrease the risk of PD. MNI focused on general geriatric approaches and supportive nursing care. On the day before surgery and the first three postoperative days, nocturnal (20:00-8:00) urine samples were collected. The melatonin sulfate and cortisol levels in the urine samples were determined. Moreover, the RASS (Richmond Agitation Sedation Scale), CAM-ICU (Confusion Assessment Method for the Intensive Care Unit) and QoR40 (40-item quality of recovery score) scores were dynamically monitored.

RESULTS

There were no significant differences in the general characteristics between the 2 groups. After surgery, the melatonin sulfate levels in the nocturnal urine of Group I were higher than those in Group U. The cortisol concentrations were lower in Group I compared to those in Group U. Group I achieved better postoperative RASS and QoR40 scores than Group U. Compared to Group U, Group I also experienced less PD (incidence and duration).

CONCLUSIONS

MNI ameliorated some postoperative disturbances regarding sleep and stress, decreased the incidence of PD and improved recovery quality.