Postoperative delirium and changes in the blood-brain barrier, neuroinflammation, and cerebrospinal fluid lactate: a prospective cohort study

Exploratory randomised trial of tranexamic acid to decrease postoperative delirium in adults undergoing lumbar fusion-a trial stopped early

Background

Postoperative delirium may be mediated by systemic inflammation and neuroinflammation. By inhibiting the proinflammatory actions of plasmin, tranexamic acid (TXA) may decrease postoperative delirium. To explore this hypothesis, we modified an ongoing randomised trial of TXA on blood loss, adding measures of delirium, cognition, systemic inflammation, and astrocyte activation.

Methods

Adults undergoing elective posterior lumbar fusion randomly received intraoperative i.v. TXA (n=43: 10 mg kg-1 loading dose, 2 mg kg-1 h-1 infusion) or placebo (n=40). Blood was collected before surgery and 24 h after surgery (n=32) for biomarkers (cytokines and S100B). Participants had twice daily delirium assessments (n=65). Participants underwent four measures of cognitive function before surgery and during post-discharge follow-up.

Results

Postoperative blood loss was ∼38% less in the TXA group compared with the placebo group with medians of 128 and 207 ml level-1, respectively, P=0.013. Total blood loss in the TXA and placebo groups did not differ with medians of 305 and 333 ml level-1, respectively, P=0.472. Delirium incidence in the TXA group (7/32=22%) was not significantly less than in the placebo group (11/33=33%); P=0.408, effect size =-0.258 (95% confidence interval -0.744 to 0.229).

Conclusions

A potential 33% relative decrease in postoperative delirium incidence justifies an adequately powered clinical trial to determine if intraoperative TXA decreases delirium in adults undergoing lumbar fusion.

Clinical trial registration

NCT04272606.

Glucose-to-Albumin Ratio as a New Predictive Indicator for Postoperative Delirium in Geriatric Hip Fracture Patients

BACKGROUND

Predicting postoperative delirium (POD) in patients who have hip fractures is challenging due to its complex mechanism. Therefore, there is a critical need to explore and evaluate a novel predictive indicator.

METHODS

There were four hematological markers independently associated with POD that were utilized to construct and evaluate a more reliable predictive indicator for POD. The study employed random sampling, dividing the data into training and validation cohorts in a 7:3 ratio. The strength of association between each predictive indicator and POD was assessed using multivariable logistic analysis and propensity score matching analysis. Predictive indicators with significant correlations underwent receiver operating characteristic curve and characteristic parameter comparisons to identify the optimal predictive indicator. Subsequent validation included the assessment of discriminative ability, correlation, and predictive performance. Furthermore, subgroup analysis was conducted to explore potential interactions. A total of 1,807 patients were included in this study, with a POD incidence rate of 16.5%.

RESULTS

Multivariable logistic analysis and propensity score matching analysis demonstrated that the glucose-to-albumin ratio (GAR) was independently positively associated with POD. Specifically, for every 0.1 unit increase in preoperative GAR levels in hip fracture patients, the risk of POD increased by 1.6 times. The receiver operating characteristic curve curve indicated that the optimal cutoff value for the GAR was 0.2, with an area under the curve of 0.8, sensitivity of 81.2%, and specificity of 59.0%.

CONCLUSIONS

Preoperative GAR has a certain predictive value for the occurrence of POD and can function as a novel indicator for predicting POD in geriatric hip fracture patients.

Prostaglandin endoperoxide synthase 2 regulates neuroinflammation to mediate postoperative cognitive dysfunction in mice

Prostaglandin endoperoxide synthase 2 (PTGS2) is a rate-limiting enzyme of prostaglandin (PGs) production, mediating perioperative inflammatory response. This study aimed to explore the mechanisms underlying the involvement of PTGS2 in postoperative cognitive dysfunction (POCD). Transient bilateral common carotid artery occlusion (tBCCAO) was performed to induce POCD. The Morris water maze test was used to assess the cognitive function. PTGS2 expression in the hippocampus and plasma was measured. Hippocampal RNA sequencing was performed to determine the pathological basis of POCD. In vivo, the mice were treated with or without a selective PTGS2 inhibitor during the perioperative period. The hippocampi were isolated to detect inflammation and oxidative damage. In vitro, PTGS2 was silenced in BV2 microglial cell lines, and oxygen-glucose deprivation/reoxidation (OGD/R) was performed. Conditioned medium from BV2 cells was collected to culture HT22 hippocampal neurons. Proinflammatory factors and oxidative damage were detected in BV2 and HT22 cells, respectively. The results indicated that the expression of PTGS2 in the plasma and hippocampal tissue of POCD mice was increased and that hippocampal inflammation is an important biological process in POCD. Inhibition of PTGS2 alleviated hippocampal inflammation, and the Morris water maze test showed improved learning and memory functions that were previously impaired. In addition, the inhibition of PTGS2 prevents OGD/R-induced microglial activation and alleviates neuronal injury. In conclusion, PTGS2 may be a culprit in POCD.

A correlational study of plasma galectin-3 as a potential predictive marker of postoperative delirium in patients with acute aortic dissection

This study aimed to demonstrate whether plasma galectin-3 could predict the development of postoperative delirium (POD) in patients with acute aortic dissection (AAD). Prospective, observational study. Cardiac surgery intensive care unit. Consecutive patients who were diagnosed with AAD and operated at the Cardiac Medical Center of Fujian Province between December 2020 and December 2022. Patients were classiffed into two groups according to the Confusion Assessment Method for the Intensive Care Unit: POD group and NON-POD group. Each patient's plasma was tested before emergency surgery. Baseline demographic data and preoperative, intraoperative, and postoperative clinical data were collected. The short-term clinical outcomes were followed up daily. The rate of POD was calculated. The risk factors for POD were analyzed through univariate analysis and multivariate logistic regression. Receiver operating characteristic (ROC) curves were used to assess the ability of plasma galectin-3 to predict POD. A total of 309 study subjects were included in this study, and the rate of POD was 38.8%. Patients with AAD were categorized into the POD and NON-POD cohorts postoperatively based on their CAM-ICU scores. There was no statistically significant difference in the baseline characteristics between the two groups (P > 0.05). However, patients in the POD group had significantly elevated plasma galectin-3 levels (P < 0.001). The ROC curves showed that plasma galectin-3 had a sensitivity of 72.5% and a specificity of 70.9% as a potential biomarker for the diagnosis of POD. The critical value of plasma galectin-3 for diagnosing POD was 9.18 ng/mL. Plasma galectin-3 levels remained an independent predictor of POD after controlling for different variables (P < 0.001). Elevated plasma galectin-3 levels are associated with an increased risk of POD. Plasma galectin-3 may be a prospective biomarker for predicting POD.

The intersection of delirium and long-term cognition in older adults: the critical role of delirium prevention

Delirium, a neuropsychiatric syndrome characterized by an acute and usually reversible state of confusion, while dementia is a chronic, acquired cognitive impairment that significantly reduces a patient's ability to perform daily tasks, learn, work, and engage in social interactions. Previous studies indicates that individuals with dementia are more susceptible to delirium than the general population, and that delirium serves as an independent risk factor for the subsequent onset of dementia. However, a major controversy in this field concerns whether delirium is merely a marker of vulnerability to dementia, or whether delirium-induced adverse outcomes such as falls and functional decline contribute to dementia, or whether delirium directly causes permanent neuronal damage and lead to dementia. It is possible that all these hypotheses hold some truth. In this review, we examine the shared and distinct mechanisms of delirium and dementia by reviewing their clinical features, epidemiology, clinicopathological, biomarkers, neuroimaging, and recent experimental studies, and we discuss the importance of targeting delirium to explore new preventive and therapeutic strategies for reducing long-term cognitive impairment.

Interleukin-6 in neuroimmunological disorders: Pathophysiology and therapeutic advances with satralizumab

Interleukin-6 (IL-6) is a multifunctional cytokine produced by various cells of the innate and adaptive immune systems. It acts as a regulatory factor in immunity, inflammation, metabolism, and cellular function in multiple organs and systems. The functionality of IL-6 is achieved through multiple signal transduction pathways, such as the JAK/STAT and the NF-κB signaling pathways. In this review, we highlighted the inflammatory and non-inflammatory functions of IL-6, as well as the associated signaling pathways. The involvement of IL-6 in neuroimmunological disorders suggests that the interleukin-6 receptor (IL-6R) monoclonal antibody, satralizumab, is a potential therapeutic strategy. Phase III clinical trials have already validated the safety and efficiency of satralizumab in treating neuromyelitis optica spectrum disorders (NMOSD) and acetylcholine receptor (AChR) seropositive generalized myasthenia gravis (gMG). This review aims to elucidate the pathophysiological role of IL-6, and explore the clinical implications of satralizumab in neuroimmunological diseases, providing insights into its potential therapeutic applications.

Lipid dysregulation and delirium in older adults: A review of the current evidence and future directions

Delirium is a complex medical condition marked by acute episodes of cognitive dysfunction and behavioral disturbances, with a multifaceted etiology and challenging management across various clinical settings. Older adults, particularly in postoperative contexts, are at increased risk of developing delirium. Despite extensive research, a single underlying pathophysiological mechanism for delirium remains elusive. However, emerging evidence suggests a correlation between lipid dysregulation and delirium development in elderly patients, especially in postoperative settings. This connection has led to proposed treatments targeting dyslipidemia and associated neuroinflammatory effects in acute-phase delirium. This review aims to synthesize current literature on the relationship between lipid dysregulation and delirium in older adults, highlighting the need for further research into specific neurolipidome constituents and age-related lipid profile changes, potentially uncovering novel therapeutic strategies for delirium.

Interpretable machine learning model for predicting delirium in patients with sepsis: a study based on the MIMIC data

OBJECTIVE

The aim of this study was to construct interpretable machine learning models to predict the risk of developing delirium in patients with sepsis and to explore the impact of delirium on the 28-day survival rate of patients.

METHODS

We enrolled 10,321 patients with sepsis older than eighteen years from the MIMIC-IV (Medical Information Mart for Intensive Care) database. Sepsis is defined as the presence or suspected presence of infection, along with a SOFA (Sequential Organ Failure Assessment) score of ≥ 2. Four machine learning models, namely XGBoost (extreme gradient Boost), SVM (support vector machine), Logistic (logistic regression) and RF (random forest), were established for prediction, and the prediction model was constructed.

RESULTS

A total of 10,321 sepsis patients were included, among whom 4,691 (45.45%) developed delirium. The 28-day mortality rate was markedly elevated in the delirium group (log-rank P < 0.001). The XGBoost model has the best performance. Finally, 5 variables were selected to draw a nomogram: hypertension, SOFA score, chlorine, Hb (hemoglobin), creatinine. The receiver operating characteristic (ROC) curve of the predictive delirium model showed better predictive efficiency, with an AUC of 0.767 (95%CI (confidence interval): 0.726-0.798).

CONCLUSION

The nomogram built on the XGBoost model provides clinicians with an easy tool to quickly assess the risk of developing delirium in patients with sepsis. It provides a new idea and direction for the best model to predict delirium in patients with sepsis, so as to promote the development of delirium related research.

Association Between Plasma Amyloid-Beta 42 Ratio and Postoperative Delirium in Elderly Patients Undergoing Major Abdominal Surgery: Secondary Analysis of a Randomized Controlled Trial

INTRODUCTION

Cerebrospinal fluid Aβ42 has been proposed as a potential indicator for cerebral β-amyloidosis and may be involved in the pathophysiology of delirium. Whether perioperative plasma Aβ42 alternation is associated with postoperative delirium risk among elderly patients remains unknown.

METHODS

This was a secondary analysis of a randomized controlled trial evaluating the effects of acupuncture (intervention) compared to standard care (control) on the incidence of delirium in patients undergoing major abdominal surgery. Participants with blood samples collected were included in this cohort study. The exposure variable was the Aβ42 ratio, calculated with the plasma Aβ42 level immediately after surgery divided by the preoperative plasma Aβ42 level. The primary endpoint was the occurrence of delirium within the first 7 days following surgery or until hospital discharge, whichever happened first, evaluated using either the Confusion Assessment Method or the Confusion Assessment Method-intensive care unit for intubated patients. Delirium severity was a secondary outcome assessed by the Memorial Delirium Assessment Scale. The logistic regression models and a restricted cubic spline were performed to examine the association between the Aβ42 ratio and delirium incidence, with receiver operating characteristic curve (ROC) analysis for diagnostic power. The mediation effects of the matrix metalloproteinase-9 ratio were further explored by causal mediation analysis. The linear regression and generalized linear mixed models assessed the association between the Aβ42 ratio and delirium severity.

RESULTS

A total of 195 patients with blood samples collected were included in the final analysis. Among them, the mean age was 70.2 ± 4.2 years; 134 were female (68.7%), and 26 (13.3%) patients experienced postoperative delirium. The plasma Aβ42 ratio was positively correlated with an increased delirium risk (adjusted odds ratio 3.21, 95% confidence interval 1.71-6.05, p < 0.001) and delirium severity, as measured by the highest postoperative Memorial Delirium Assessment Scale score (adjusted β coefficient 3.04, 95% confidence interval 0.9-5.18, p = 0.006) in the fully adjusted multivariable analysis models. The restricted cubic spline indicated a linear relationship between the plasma Aβ42 ratio and delirium incidence (p = 0.202). The ROC showed that the area under the curve for the Aβ42 ratio to predict delirium risk was 0.698 (95% CI, 0.582-0.814), with the optimal cut-off point of 0.137. Mediation analyses showed that the Aβ42 ratio does not mediate postoperative delirium through the matrix metalloproteinase-9 ratio (proportion: 1.3%).

CONCLUSIONS

This cohort study showed that a higher Aβ42 ratio was associated with an increased delirium risk and severity, and the association was linear. The plasma Aβ42 ratio might be a mini-invasive biomarker to identify postoperative delirium.

Mechanisms of perioperative neuronal injury and the search for therapies

Perioperative neuronal injury includes both delirium and postoperative cognitive decline, and has profound potentially long-term effects on surgical patients and an economic cost. Recent advances have been made in the underlying biological causes of these injuries, including validation of biomarkers of neuronal damage such as neurofilament light, further understanding of the inflammatory pathways and mediators responsible for neuronal injuries, metabolic triggers, and the role of ischaemia. Several novel approaches to perioperative protection of brain health are also being trialled. We summarise the current evidence regarding the causes of neuronal injury, and work taking place related to its prevention and treatment.

The immune-inflammatory responses on the hypothalamic-pituitary-adrenal axis and the neurovascular unit in perioperative neurocognitive disorder

Perioperative neurocognitive disorders (PNDs) refer to a wide spectrum of cognitive impairment persisting days to even after a year postoperative with significant morbidity and mortality. However, despite much efforts involving perioperative managements, PNDs are still prevalent with no standard preventative and therapeutic strategy. To overcome PNDs, a better understanding of pathophysiology of PNDs is crucial and a large number of studies have proven that immune-inflammatory responses from surgical stress are involved in the abnormal activation of the hypothalamic-pituitary-adrenal (HPA) axis and destabilization of neurovascular unit (NVU) that lead to PNDs. The HPA axis is one of the key components to maintaining physiological homeostasis in response to stress. Under normal conditions, the HPA axis is involved in multiple roles from memory consolidation to regulating the circadian rhythm by activating adrenal cortex to secret cortisol. However, when overwhelmed with inflammatory response from surgical stress, HPA axis may be abnormally activated to release excessive glucocorticoids to cause PNDs. In addition, NVU, the functional unit of the brain essential for maintaining blood brain barrier and cerebral blood flow, is another possible factor that may lead to PNDs as compromised NVU from inflammatory response can result in disrupted blood brain barrier and impaired brain homeostasis. Therefore, the interaction of immune-inflammatory response with the HPA axis and the NVU seems to play a significant role and therapeutic and/or preventive strategies focused on these interactions may be promising direction for future managements of PNDs.

Associations of metabolic dysfunction-related fatty liver disease and dementia risk: A prospective study based on the UK biobank

BACKGROUND

Metabolic dysfunction-associated fatty liver disease (MAFLD) has garnered increasing attention for its potential link with dementia. This study aims to investigate the association between MAFLD and dementia, including its subtypes, to address existing knowledge gaps.

METHODS

A total of 415,116 participants from the UK Biobank were included, with standardized screening criteria used to determine MAFLD diagnosis. Cox regression was employed to assess the relationship between MAFLD and dementia risk. Subgroup analyzes were conducted to provide further insights into the impact of MAFLD on dementia risk, and the mediation effect of inflammation was evaluated.

RESULTS

Among the 150,509 MAFLD patients, there was a significantly elevated risk of dementia, with hazard ratios (HR) of 1. 526 (95 % CI = 1. 460-1. 596) for all-cause dementia, 1. 356 (95 % CI = 1. 266-1. 453) for Alzheimer's disease (AD), and 2. 206 (95 % CI = 2. 000-2. 434) for vascular dementia (VaD). MAFLD patients showed a significant reduction in gray matter volume in MAFLD patients (β = -0. 07, 95 % CI = -0. 17, -0. 01) and a marked increase in deep white matter lesion volume (P < 0. 001). Elevated inflammatory markers in MAFLD patients accounted for a mediation effect of 30. 8 %.

CONCLUSION

MAFLD substantially increases the risk of dementia, underscoring the importance of early intervention and prevention strategies targeting MAFLD to reduce dementia incidence.

Effect of stellate ganglion block on delirium after major surgery in elderly patients: protocol for a randomised controlled study

INTRODUCTION

Postoperative delirium (POD) remains a prevalent neurological complication among elderly patients following major surgeries, with limited effective preventive measures currently available. Stellate ganglion block (SGB) is widely employed in clinical practices to manage various conditions by modulating the sympathetic nervous system activity. However, there is currently a lack of clinical evidence assessing its effect on the incidence of POD. This study aims to evaluate the safety and efficacy of SGB as a preventive strategy for POD in elderly patients undergoing major surgeries.

METHODS AND ANALYSIS

This randomised controlled clinical trial will be conducted at two centres, enrolling a total of 300 elderly patients aged 65 years and older who are scheduled for elective major surgery. Participants will be randomly assigned to either the SGB group (n=150) or the control group (n=150). In the SGB group, participants will receive an ultrasound-guided SGB using 7 mL of local anaesthetic, while the control group will receive 2 mL of saline injected into the muscle tissue on the anterolateral side of the SG. The primary outcome will be the occurrence of POD within 7 days postsurgery or before discharge. POD will be assessed two times per day using either the confusion assessment method (CAM) or the CAM for the intensive care unit. Secondary outcomes will include the severity of POD, postsurgical sleep quality, overall recovery quality and the incidence of adverse events.

ETHICS AND DISSEMINATION

The trial protocol has been approved by the Ethics Committees of the Affiliated Hospital of Jiaxing University (approval number 2023-KY-479) and Sir Run Run Shaw Hospital, Zhejiang University School of Medicine (approval number 2023-0747). Written informed consent will be obtained from all participants prior to study inclusion. Data collected will be disseminated at scientific conferences and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ChiCTR 2300077883.

Relationship Between Peripheral Serum Adiponectin and Cerebrospinal Fluid TNF-α, IL-1β, Lactic Acid, Pyruvic Acid and Perioperative Neurocognitive Dysfunction in Elderly Patients Undergoing Hip Arthroplasty

Background

Postoperative neurocognitive dysfunction (PND) represents a form of cognitive impairment related to surgery and anesthesia, which may manifest hours or even weeks after the surgical procedure, persist, and potentially progress into Alzheimer's disease. The etiology of PND is intricate, with central nervous inflammation playing a crucial role. The clinical manifestations of PND are not distinctive, no obvious image alterations are observable, and the diagnosis rate is relatively low, thereby influencing prognosis and augmenting postoperative complications and mortality. The optimal treatment approach for PND lies in timely identification and management of the high-risk factors causing PND and implementing early prevention. We hypothesize that the level of peripheral blood adiponectin (APN) is correlated with PND, potentially through inhibiting the central inflammatory response and regulating brain energy metabolism.

Methods

Fifty elderly patients undergoing elective hip arthroplasty under continuous epidural spinal anesthesia (CESA) were included. Cognitive function was assessed using the Mini-Mental State Examination (MMSE) preoperatively and postoperatively at 1, 2, 3, and 7 days. Serum APN and CSF levels of TNF-α, IL-1β, lactic acid, and pyruvic acid were measured. The occurrence of PND was recorded, and the patients were divided into a PND group and a non-PND group.

Results

PND occurred in 16 patients (34.04%). The PND group had lower serum APN levels and higher cerebrospinal fluid (CSF) concentrations of TNF-α, IL-1β, and lactic acid compared to the non-PND group. CSF TNF-α and IL-1β levels were negatively correlated with serum APN concentration. These biomarkers are associated with PND occurrence and have high diagnostic value.

Conclusion

Decreases in serum APN and increases in TNF-α, IL-1β, and lactic acid in CSF may be involved in the pathophysiological process of PND in elderly patients after surgery.

Predictors of postoperative delirium in patients undergoing radical prostatectomy: a prospective study

BACKGROUND

Analyze the risk factors for postoperative delirium (POD) in elderly patients undergoing radical prostatectomy, and built a predictive nomogram model for early identification of high-risk individuals.

METHODS

A total of 156 patients was recruited and categorized based on whether the development of POD within 7 days post-surgery. After identifying independent risk factors through univariate and multivariate logistic regression analyses, predictive models were established. The discrimination and calibration were determined by C-index and calibration curve, with five-fold cross-validation executed. A nomogram model representing the optimal model was constructed based on the results.

RESULTS

POD occurred in 24 (15.38%) patients. Significant differences were observed in age, anxiety, physical status, sleep disorders, blood glucose, age-adjusted Charlson comorbidity index (ACCI), anticholinergic, blood loss, postoperative infection, and postoperative pain assessed by the numerical rating scale (NRS). Logistic regression analyses showed that sleep disorders (OR:12.931, 95% CI:1.191-140.351, P = 0.035), ACCI (OR:2.608, 95% CI:1.143-5.950, P = 0.023), postoperative infection (OR:19.298, 95% CI:2.53-147.202, P = 0.04), and NRS (OR:4.033, 95% CI:1.062-15.324, P = 0.041) were independent risk factors for POD. Model 1 (postoperative infection, ACCI, preoperative sleep disorder, NRS) showed better diagnostic performance than the others, of which the area under the curve (AUC) was 0.973. The best diagnostic performance was found in model 1 through five-fold cross-validation, with a C-index of 0.963.

CONCLUSIONS

This prospective cohort study highlighted that ACCI, preoperative sleep disorder, postoperative pain, and postoperative infection were identified as independent risk factors for POD. Furthermore, the nomogram derived from model 1 proved to be effective in predicting POD in elderly patients undergoing radical prostatectomy.

Effects of neostigmine on postoperative neurocognitive dysfunction: a systematic review and meta-analysis

Introduction

Postoperative neurocognitive dysfunction (PND) is a common and serious complication following surgery. Neostigmine, an acetylcholinesterase inhibitor commonly administered during anesthesia to reverse residual neuromuscular blockade, has been suggested in recent studies to potentially reduce the incidence of PND. However, findings have been inconsistent across studies. Therefore, this study conducts a systematic review and meta-analysis to evaluate the effect of neostigmine on PND.

Methods

We conducted a comprehensive literature search across multiple databases, including PubMed, EmBase, Web of Science, Cochrane Library, Scopus, SinoMed, and CNKI, to identify all relevant studies for inclusion. We included randomized controlled trials and cohort studies in our analysis. The risk of bias was assessed using the Risk of Bias 2 tool for randomized trials and the ROBINS-I tool for cohort studies.

Results

A total of 11 studies were included in this analysis, consisting of 8 randomized controlled trials and 3 cohort studies. The incidence of PND was significantly lower in the neostigmine group compared to the control group (log(OR): -0.54, 95% CI [-1.04, -0. 05]; OR: 0.58, 95% CI: [0.35, 0.95], p = 0.03, I2 = 81.95%). Sensitivity analysis led to the exclusion of one cohort study. Consequently, the final meta-analysis comprised 10 studies, encompassing a total of 50,881 participants. The results indicate that the incidence of PND was significantly lower in the neostigmine group compared to the control group (log(OR):-0. 27, 95% CI [-0.47, -0. 08]; OR: 0.76, 95% CI: [0.62, 0.91], p = 0.01, I2 = 2.50%). However, Meta-analysis of RCTs and cohort studies showed no significant difference. Subgroup analysis indicated that neostigmine reduced the incidence of delayed neurocognitive recovery (dNCR), but its impact on POD was unclear, with no significant association to nausea and vomiting. These findings suggest that neostigmine may reduce the risk of PND, but caution is needed in interpretation.

Conclusion

Neostigmine may have a potential positive effect in reducing the incidence of PND. However, no statistical difference was observed when meta-analyses were performed separately for randomized controlled trials (RCTs) and cohort studies. Given the limited number of studies available and the limitations of the current research, further investigation is needed to clarify the impact of neostigmine on PND.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/view/CRD42024537647, Identifier CRD42024537647.

Lactate improves postoperative cognitive function through attenuating oxidative stress and neuroinflammation in aged mice via activating the SIRT1 pathway

Postoperative cognitive dysfunction (POCD) is a recognized clinical phenomenon characterized by cognitive impairment in patients following anesthesia and surgery, especially in the elderly. However, the pathogenesis of POCD remains unclear. In the last decades, lactate's neuroprotective properties have been increasingly mentioned. The study tested the hypothesis that lactate may attenuate the cognitive impairment induced by anesthesia and surgery in aged mice through SIRT1-dependent antioxidant and anti-inflammatory effects. We used 18-month-old C57BL/6 mice to establish the POCD animal model by exploratory laparotomy with isoflurane anesthesia. For the interventional study, mice were administered lactate, with or without the potent and selective SIRT1 inhibitor EX-527. Behavioral tests including open field (OF), Y maze and fear conditioning (FC) tests were performed from 4 to 7 days after anesthesia and surgery. Immunofluorescence staining and Western blot were employed to assess oxidative damage, activation of microglia and astrocytes, levels of proinflammatory cytokines, and the expression of plasticity-related proteins. Lactate treatment can ameliorate oxidative stress, neuroinflammation, and the decreased levels of plasticity-related proteins induced by anesthesia and surgery, ultimately improving cognitive impairment in aged mice. However, co-treatment with lactate and EX-527 diminished the beneficial effects. Our study indicates that the mechanisms underlying neuroprotective properties of lactate might be related to its antioxidant and anti-inflammatory effects, and improvement of hippocampal synaptic plasticity through activation of SIRT1 pathway.

Role of glia in delirium: proposed mechanisms and translational implications

Delirium is a common acute onset neurological syndrome characterised by transient fluctuations in cognition. It affects over 20% of medical inpatients and 50% of those critically ill. Delirium is associated with morbidity and mortality, causes distress to patients and carers, and has significant socioeconomic costs in ageing populations. Despite its clinical significance, the pathophysiology of delirium is understudied, and many underlying cellular mechanisms remain unknown. There are currently no effective pharmacological treatments which directly target underlying disease processes. Although many studies focus on neuronal dysfunction in delirium, glial cells, primarily astrocytes, microglia, and oligodendrocytes, and their associated systems, are increasingly implicated in delirium pathophysiology. In this review, we discuss current evidence which implicates glial cells in delirium, including biomarker studies, post-mortem tissue analyses and pre-clinical models. In particular, we focus on how astrocyte pathology, including aberrant brain energy metabolism and glymphatic dysfunction, reactive microglia, blood-brain barrier impairment, and white matter changes may contribute to the pathogenesis of delirium. We also outline limitations in this body of work and the unique challenges faced in identifying causative mechanisms in delirium. Finally, we discuss how established neuroimaging and single-cell techniques may provide further mechanistic insight at pre-clinical and clinical levels.

The Association of Fructose Metabolism With Anesthesia/Surgery-Induced Lactate Production

BACKGROUND

In elderly individuals, excessive lactate levels in the brain may be associated with the development of cognitive impairment after surgery, including delayed neurocognitive recovery (dNCR). Since the origin of this increased lactate is unknown, here we assessed associations between metabolic pathways and postoperative dNCR.

METHODS

This study included 43 patients (≥60 years old) who had surgery under general anesthesia. We also used a mouse model in which 20-month-old mice were exposed to sevoflurane to induce postoperative dNCR, while control mice were exposed to 40% oxygen. Mice in the control group and anesthesia/surgery group were injected with fructose or glucose intracerebroventricularly, or fructose metabolism inhibitor intraperitoneally. Barnes maze test and Y maze were used to measure cognitive function in mice. Metabolomics was used to measure metabolites in the serum of patients and the brains of mice after anesthesia/surgery. Isotope labeling and metabolic flux were used to analyze flow and distribution of specific metabolites in metabolic pathways.

RESULTS

Among 43 patients, 17 developed dNCR. Metabolomics showed significantly decreased postoperative serum fructose 1-phosphate levels in dNCR compared to nondNCR patients (mean difference [×10 4 ] = -0.164 ± 0.070; P = .024). Similar results were found in the brains of mice (mean difference = -1.669 ± 0.555; * P = .014). Isotope labeling and metabolic flux experiments in mice showed fructose but not glucose entered glycolysis, increasing lactate levels in the brain after anesthesia/surgery ( P < .05). Administration of intraperitoneal fructose inhibitors to mice effectively inhibited increased lactate levels in the brain (mean difference =96.0 ± 4.36, P = .0237) and cognitive dysfunction after anesthesia/surgery (mean difference =69.0 ± 3.94, P = .0237). In a small subsample, we also found anesthesia/surgery increased interleukin-6 (IL-6) levels in the brains of mice (mean difference =88.3 ± 3.44, P = .0237) and that IL-6 may function upstream in fructose activation.

CONCLUSIONS

These results suggest that anesthesia/surgery activates fructose metabolism, producing excessive lactate in the brain that is associated with postoperative cognitive impairment. Fructose metabolism is thus a potential therapeutic target for dNCR.

Functional MRI-based machine learning strategy for prediction of postoperative delirium in cardiac surgery patients: A secondary analysis of a prospective observational study

STUDY OBJECTIVE

Delirium is a common complication after cardiac surgery and is associated with poor prognosis. An effective delirium prediction model could identify high-risk patients who might benefit from targeted prevention strategies. We introduce machine learning models that employ resting-state functional MRI datasets obtained before surgery to predict postoperative delirium.

DESIGN

A secondary analysis of a prospective observational study.

SETTING

The study was conducted at one tertiary hospital in China.

PATIENTS

The study involved 103 patients who underwent preoperative functional MRI scan and cardiac valve replacement.

INTERVENTIONS

None.

MEASUREMENTS

Delirium was assessed twice daily for the first seven postoperative days using the Confusion Assessment Method. We used three whole-brain functional connectivity (FC) measures (parcel-wise connectivity matrix, mean FC and degree of FC) and trained three machine models, namely, random forest, logistic regression, and linear support vector machine, to distinguish delirium patients from patients without delirium. The top performing model was selected for further training with functional MRI datasets and clinical variables.

MAIN RESULTS

This study included 103 participants. A total of 29 participants (28.2 %) met postoperative delirium criteria. Based solely on functional MRI datasets, the random forest model trained using the degree of FC achieved the highest accuracy (0.864), precision (0.887), specificity (0.894), F1 score (0.859) and area under the curve (0.924), and this model was further optimized for accuracy (0.879), sensitivity (0.909), F1 score (0.882) and area under the curve (0.928) by fusing clinical variables. The most discriminative nodes for predicting postoperative delirium were located in the default, cingulo-opercular, and frontoparietal networks.

CONCLUSIONS

This study found that the random forest model using preoperative functional MRI data and clinical variables was accurate in identifying patients at high risk of developing delirium after cardiac surgery.

Brain Structural and Functional Changes Associated With Postoperative Neurocognitive Disorders: Research Update

Postoperative neurocognitive disorders (PNDs) are frequent and serious perioperative complications in the elderly, and are associated with increased morbidity and mortality, length of hospital stay, and need for long-term care. At present, the pathogenesis of PND is not completely clear, and there are various risk factors including surgical trauma and stress mediating systemic inflammation towards neuroinflammation development which causes brain structural and functional changes namely PND. For elderly patients, perioperative neurological monitoring may provide insights into brain function status. Monitoring may also help clinicians identify potential risks which would ultimately allow timely and effective intervention for better perioperative safety and prognosis for elderly patients. In this review, we summarize the risk factors and potential mechanisms of PND, and discuss preliminary evidence regarding application of electroencephalography, functional near-infrared spectroscopy, functional magnetic resonance, and positron emission tomography imaging in monitoring the central nervous system during the postoperative period.

The Role of Cytokines in Perioperative Neurocognitive Disorders: A Review in the Context of Anesthetic Care

Perioperative neurocognitive disorders (PNDs), including postoperative delirium, delayed neurocognitive recovery, and long-term postoperative neurocognitive disorders, present significant challenges for older patients undergoing surgery. Inflammation is a protective mechanism triggered in response to external pathogens or cellular damage. Historically, the central nervous system (CNS) was considered immunoprivileged due to the presence of the blood-brain barrier (BBB), which serves as a physical barrier preventing systemic inflammatory changes from influencing the CNS. However, aseptic surgical trauma is now recognized to induce localized inflammation at the surgical site, further exacerbated by the release of peripheral pro-inflammatory cytokines, which can compromise BBB integrity. This breakdown of the BBB facilitates the activation of microglia, initiating a cascade of neuroinflammatory responses that may contribute to the onset of PNDs. This review explores the mechanisms underlying neuroinflammation, with a particular focus on the pivotal role of cytokines in the pathogenesis of PNDs.

Intranasal Insulin Diminishes Postoperative Delirium and Elevated Osteocalcin and Brain Derived Neurotrophic Factor in Older Patients Undergoing Joint Replacement: A Randomized, Double-Blind, Placebo-Controlled Trial

Background

Brain energy metabolism disorders, including glucose utilization disorders and abnormal insulin sensitivity, are linked to the pathogenesis of postoperative delirium. Intranasal insulin has shown significant benefits in improving glucose metabolism, insulin sensitivity and cognitive function. However, its impact on postoperative delirium and insulin sensitivity biomarkers remains unknown.

Aim

This randomized, double-blind, placebo-controlled trial was to evaluate whether intranasal insulin reduces the incidence and severity of postoperative delirium (POD) in older patients undergoing joint replacement, and its effect on insulin sensitivity-related biomarkers.

Methods

212 older patients (≥65 years) were randomly assigned to receive either 40 IU of intranasal insulin (n=106) or a placebo (n=106) for 8 days. The primary objective was to determine the incidence and severity of POD within 5 days after surgery, estimated using the Confusion Assessment Method (CAM) and the Delirium Rating Scale (DRS)-98. The secondary objective was insulin sensitivity, which was assessed using the homeostasis model Assessment of Insulin Resistance (HOMA-IR) and biomarkers, including total osteocalcin (tOC), uncarboxylated osteocalcin (ucOC), and brain-derived neurotrophic factor (BDNF).

Main Results

Compared to placebo, intranasal insulin significantly reduced the incidence of delirium within 5 days after surgery (8 [8.33%] vs 23 [23.23%], P = 0.004, odds ratio [OR] = 3.33 [95% CI 1.41-7.88]) and the severity of delirium (P<0.001). Intranasal insulin elevated the levels of tOC, ucOC, and BDNF in the CSF on D0 (all P<0.001) and tOC levels in the plasma on D0, D1 and D3 (all P<0.001). It elevated ucOC levels in the plasma of the insulin group on D0 but not on D1 and D3 (all P<0.001). Intranasal insulin administration reduced the HOMA-IR on D3 (P=0.002).

Conclusion

Intranasal insulin notably reduced the incidence and severity of POD in older patients undergoing joint replacement, which may be related to the elevation in osteocalcin and BDNF levels.

Trial Registry Numbers

Chinese Clinical Trial Registry (ChiCTR2300068073).

Chemokine associations with blood cerebrospinal fluid (CSF) barrier permeability and delirium

Delirium is a highly prevalent neuropsychiatric syndrome characterised by acute and fluctuating impairments in attention and cognition. Mechanisms driving delirium are poorly understood but it has been suggested that blood cytokines and chemokines cross the blood brain barrier during delirium, directly impairing brain function. It is not known whether these molecules reach higher brain levels when the blood cerebrospinal fluid barrier (BCSFB) is impaired. Here, in human hip-fracture patients, we tested the influence of BCSFB integrity on CSF levels of chemokines and assessed their association with delirium. CSF levels of IP-10, eotaxin, eotaxin 3 and TARC showed weak to moderate correlations with BCSFB permeability, as measured by the Qalbumin ratio, while MCP1, IL-8, MIP1α and MIP1β showed no significant correlation. Chemokines were not associated with delirium in univariate analysis or when stratified on dementia status, but exploratory analyses showed that elevated Eotaxin (CCL11) and MIP1α (CCL3) were associated with prevalent delirium. Modelling acute systemic inflammation, we used bacterial LPS (250 μg/kg) or sterile laparotomy surgery in mice to demonstrate de novo synthesis of chemokines at the choroid plexus (CP) and microvasculature. Gene expression data showed CP-enriched expression of Il1b, Tnfa, Cxcl1 and Ccl3 in both models and immunohistochemistry showed cytokine and chemokine synthesis in CP stromal (IL-1β, CCL2/MCP1) or epithelial cells (CXCL10/IP-10) cells and at the microvasculature. Larger studies are required to confirm these human findings on chemokine associations with BCSFB permeability and prevalent delirium. Preclinical studies are warranted to determine whether chemokines might play a role in the pathophysiology of delirium.

Ulinastatin treatment mitigates glycocalyx degradation and associated with lower postoperative delirium risk in patients undergoing cardiac surgery: a multicentre observational study

BACKGROUND

Ulinastatin (UTI), recognized for its anti-inflammatory properties, holds promise for patients undergoing cardiac surgery. This study aimed to investigate the relationship between intraoperative UTI administration and the incidence of delirium following cardiac surgery.

METHODS

A retrospective analysis was performed on a retrospective cohort of 6,522 adult cardiac surgery patients to evaluate the relationship between UTI treatment and the incident of postoperative delirium (POD) in patients ongoing cardiac surgery. This was followed by a prospective observational cohort study of 241 patients and an in vitro study to explore the findings and the potential role of UTI in preventing cardiac ischemia-reperfusion induced glycocalyx degradation.

RESULTS

Both univariate and multivariate logistic regression analyses in retrospective cohort indicated that intraoperative administration of UTI was associated with a significant lower risk of POD among cardiac surgery patients, a finding confirmed through employing propensity score matching. The subsequent prospective observational cohort further supported these findings (adjusted Odds Ratio = 0.392, 95% CI: 0.157-0.977, P = 0.044). Furthermore, UTI mitigated glycocalyx degradation, as demonstrated by in vitro study.

CONCLUSIONS

UTI administration may mitigate glycocalyx degradation, potentially lowering the risk of POD in cardiac surgery patients, offering valuable insights for future interventions to prevent POD and enhance patient outcomes. Trial registration number ClinicalTrials.gov (No. NCT06268249). Retrospectively registered 4 February 2024.

Recent Advances in the Mechanisms of Postoperative Neurocognitive Dysfunction: A Narrative Review

Postoperative neurocognitive dysfunction (PND) is a prevalent and debilitating complication in elderly surgical patients, characterized by persistent cognitive decline that negatively affects recovery and quality of life. As the aging population grows, the rising number of elderly surgical patients has made PND an urgent clinical challenge. Despite increasing research efforts, the pathophysiological mechanisms underlying PND remain inadequately characterized, underscoring the need for a more integrated framework to guide targeted interventions. To better understand the molecular mechanisms and therapeutic targets of PND, this narrative review synthesized evidence from peer-reviewed studies, identified through comprehensive searches of PubMed, Embase, Cochrane Library, and Web of Science. Key findings highlight neuroinflammation, oxidative stress, mitochondrial dysfunction, neurotransmitter imbalances, microvascular changes, and white matter lesions as central to PND pathophysiology, with particular parallels to encephalocele- and sepsis-associated cognitive impairments. Among these, neuroinflammation, mediated by pathways such as the NLRP3 inflammasome and blood-brain barrier disruption, emerges as a pivotal driver, triggering cascades that exacerbate neuronal injury. Oxidative stress and mitochondrial dysfunction synergistically amplify these effects, while neurotransmitter imbalances and microvascular alterations, including white matter lesions, contribute to synaptic dysfunction and cognitive decline. Anesthetic agents modulate these interconnected pathways, exhibiting both protective and detrimental effects. Propofol and dexmedetomidine demonstrate neuroprotective properties by suppressing neuroinflammation and microglial activation, whereas inhalational anesthetics like sevoflurane intensify oxidative stress and inflammatory responses. Ketamine, with its anti-inflammatory potential, offers promise but requires further evaluation to determine its long-term safety and efficacy. By bridging molecular insights with clinical practice, this review highlights the critical role of personalized anesthetic strategies in mitigating PND and improving cognitive recovery in elderly surgical patients. It aims to inform future research and clinical decision-making to address this multifaceted challenge.

Anesthesia/surgery leads to blood-brain barrier disruption via the transcellular and paracellular pathways, and postoperative delirium-like behavior: A comparative study in mice of different ages

AIMS

Postoperative delirium (POD) is a common complication of anesthesia and surgery, with a higher incidence in elderly patients. Disruption of the blood-brain barrier (BBB) is considered one of the key mechanisms underlying POD. Therefore, the present study aimed to investigate the effects of different BBB permeability alteration pathways on POD in mice of various ages.

METHODS

C57BL/6 J mice aged 4 and 16 months underwent exploratory laparotomy under sevoflurane anesthesia. Behavioral tests were conducted 24 h prior to surgery, as well as 6, 9, and 24 h postoperatively. Frontal cortex tissue was collected to detect the levels of BBB-related proteins and mRNA.

RESULTS

At 6 and 9 h after anesthesia/surgery, 4-month-old mice showed poorer performance on behavioral tests than their untreated counterparts. However, 16-month-old mice exhibited worse behavioral test results at 6, 9, and 24 h after surgery. Anesthesia/surgery 6 h postoperatively increased the expression of vesicle-associated proteins, and BBB leakage in 4-month-old mice. In 16-month-old mice, anesthesia/surgery altered the expression of tight junction proteins, vesicle-associated proteins, and BBB leakage at 6 and 24 h postoperatively.

CONCLUSION

Overall, our results suggest that anesthesia/surgery leads to age-dependent cognitive decline, and is associated with differences in the BBB injury pathways among mice of different ages. The transcellular pathway (transcytosis), compared to the paracellular pathway (tight junction), is more vulnerable to damage following anesthesia/surgery. This study provides new evidence for the improvement of POD through protection of the BBB.

Advancing Delirium Treatment Trials in Older Adults: Recommendations for Future Trials From the Network for Investigation of Delirium: Unifying Scientists (NIDUS)

OBJECTIVES

To summarize the delirium treatment trial literature, identify the unique challenges in delirium treatment trials, and formulate recommendations to address each in older adults.

DESIGN

A 39-member interprofessional and international expert working group of clinicians (physicians, nurses, and pharmacists) and nonclinicians (biostatisticians, epidemiologists, and trial methodologists) was convened. Four expert panels were assembled to explore key subtopics (pharmacological/nonpharmacologic treatment, methodological challenges, and novel research designs).

METHODS

To provide background and context, a review of delirium treatment randomized controlled trials (RCTs) published between 2003 and 2023 was conducted and evidence gaps were identified. The four panels addressed the identified subtopics. For each subtopic, research challenges were identified and recommendations to address each were proposed through virtual discussion before a live, full-day, and in-person conference. General agreement was reached for each proposed recommendation across the entire working group via moderated conference discussion. Recommendations were synthesized across panels and iteratively discussed through rounds of virtual meetings and draft reviews.

RESULTS

We identified key evidence gaps through a systematic literature review, yielding 43 RCTs of delirium treatments. From this review, eight unique challenges for delirium treatment trials were identified, and recommendations to address each were made based on panel input. The recommendations start with design of interventions that consider the multifactorial nature of delirium, include both pharmacological and nonpharmacologic approaches, and target pathophysiologic pathways where possible. Selecting appropriate at-risk patients with moderate vulnerability to delirium may maximize effectiveness. Targeting patients with at least moderate delirium severity and duration will include those most likely to experience adverse outcomes. Delirium severity should be the primary outcome of choice; measurement of short- and long-term clinical outcomes will maximize clinical relevance. Finally, plans for handling informative censoring and missing data are key.

CONCLUSIONS

By addressing key delirium treatment challenges and research gaps, our recommendations may serve as a roadmap for advancing delirium treatment research in older adults.

Association of Intravenous Neostigmine and Anticholinergics or Sugammadex with Postoperative Delirium: A Retrospective Cohort Study

BACKGROUND

Administration of cholinesterase inhibitors in combination with anticholinergic drugs for reversal of neuromuscular blocks may precipitate delirium through impairment of central cholinergic transmission, which could be avoided by using sugammadex. Therefore, we tested the primary hypothesis that postoperative delirium is less common when neuromuscular block is reversed with sugammadex than with neostigmine combined with glycopyrrolate or atropine.

METHODS

We conducted a single-center retrospective cohort study, analyzing all adult patients having general anesthesia for noncardiac surgery who received neostigmine or sugammadex from January 2016 to March 2022. Inverse propensity score weighting and propensity score calibration were used to adjust for appropriate confounders. Our primary outcome was presence of delirium within the first 4 days after surgery, defined as at least 1 positive brief Confusion Assessment Method (bCAM) screening. The secondary outcome was the presence of early delirium within 24 hours of surgery.

RESULTS

Among 49,468 cases in our analysis, 6881 received sugammadex and 42,587 received neostigmine. After propensity weighting, the incidence of delirium was 1.09% in the sugammadex group and 0.82% in the neostigmine group. The odds of postoperative delirium did not differ between the sugammadex and neostigmine groups, with an estimated odds ratio (95% confidence interval) of 1.33 (0.91-1.95), P = .147. A sensitivity analysis restricted to only include cases with at least 6 bCAM measurements over postoperative day (POD) 1 to 4 had consistent results, as sugammadex compared with neostigmine was associated with an estimated odds ratio for postoperative delirium of 1.20 (0.82-1.77), P = .346. Sugammadex was significantly associated with an increased incidence of early postoperative delirium, with an estimated odds ratio of 1.71 (1.07-2.72), P = .025. Further analysis showed no treatment-by-age interaction for either postoperative delirium ( P = .637) or postoperative early delirium ( P = .904).

CONCLUSIONS

Compared to neostigmine, use of sugammadex for reversal of neuromuscular block was not associated with an increased risk of postoperative delirium in this retrospective single-center study. Though sugammadex was associated with a statistically significant increased risk of postoperative early delirium, the difference was small and not clinically relevant, and may reflect the presence of unknown confounders.

The Effects of Transcranial Direct Current Stimulation and Exercise on Salivary S100B Protein Indicated Blood-Brain Barrier Permeability: A Pilot Study

OBJECTIVE

This study aimed to assess the effect of transcranial direct current stimulation (tDCS) and exercise on blood-brain barrier (BBB) permeability in humans as assessed through the quantification of the salivary protein biomarker S100B. It was hypothesized that active tDCS would induce a significant increase in salivary S100B concentration when compared with sham stimulation and no stimulation. It also was hypothesized that the increase in salivary S100B concentration would be greater after active tDCS and exercise than after tDCS or exercise alone.

MATERIALS AND METHODS

A total of 13 healthy adults (five male, eight female), ranging in age from 21 to 32 years, underwent three experimental conditions (active tDCS, sham tDCS, inactive control). To assess exercise- and tDCS-induced changes in BBB permeability, S100B in saliva was measured. Saliva samples were taken before tDCS, after tDCS, and immediately after a ramped cycling time-to-exhaustion (TTE) task. Active tDCS involved the application of anodal stimulation over the primary motor cortex for 20 minutes at 2 mA.

RESULTS

S100B concentrations in the control condition did not differ significantly from the active condition (estimate = 0.10, SE = 0.36, t = 0.27, p = 0.79) or the sham condition (estimate = 0.33, SE = 0.36, t = 0.89, p = 0.38). Similarly, S100B concentrations at baseline did not differ significantly from post-intervention (estimate = -0.35, SE = 0.34, t = -1.03, p = 0.31) or post-TTE (estimate = 0.66, SE = 0.34, t = 1.93, p = 0.06).

CONCLUSIONS

This research provides novel insight into the effect of tDCS and exercise on S100B-indicated BBB permeability in humans. Although the effects of tDCS were not significant, increases in salivary S100B after a fatiguing cycling task may indicate exercise-induced changes in BBB permeability.

Preoperative Blood-Brain Barrier Integrity Influence on the Impact of Anesthesia and Surgery on Mice Brain

BACKGROUND

Brain homeostasis imbalance, characterized by cognitive dysfunction and delirium, frequently occurs in the elderly after surgery. Investigating why this complication only affects part of patients undergoing the same surgery, and anesthesia remains intriguing. This study tested the role of preoperative blood-brain barrier (BBB) integrity in the occurrence of postoperative brain homeostasis imbalance using mice with conditional BBB damage.

METHODS

Preoperative BBB breakdown was induced in End-SCL-Cre-ctnnb1fl//fl (iCKO) mice by administering tamoxifen (intraperitoneal [i.p.]). This breakdown was assessed using Evans Blue (EB) leakage and immunoglobulin G (IgG) staining. Postoperative brain homeostasis imbalance was evaluated through the Novel Object Recognition test, the Barnes Maze, and neuroinflammation tests. Synapse loss was detected by colabeling synaptophysin and PSD-95, followed by Western blotting. The role of astrocytes in this pathogenesis was evaluated by comparing cognitive behaviors, hippocampal gene expression, and astrocytic phagocytosis of synaptophysin in iCKO mice with and without genetic inhibition of perioperative astrocyte activity.

RESULTS

Tamoxifen treatment (30 mg/kg/d) induced BBB breakdown of iCKO mice in a time-dependent manner (analysis of variance [ANOVA] for time, P = .0006), but not in their littermate control mice (nCKO, P > .999). A 3-day tamoxifen treatment induced slight BBB breakdown (EB leakage: 95% confidence interval [CI], 13.9-204.8, P = .013; IgG level: 95% CI, 12.6-51.4: P = .001), but did not cause significant cognitive impairment in the Novel Object Recognition test in iCKO mice (95% CI, -7.99 to 6.12; P > .999). Anesthesia and surgery-induced significant cognitive impairment (all P < .0001 for the Novel Object Recognition test, Barnes Maze test), neuroinflammation, and synaptic loss in iCKO mice with 3-day tamoxifen treatment, but not in nCKO mice with the same treatment. Inhibiting astrocyte activity alleviated the impact of anesthesia and surgery on cognitive function (all P < .0001 for the Novel Object Recognition test, Barnes Maze test), gene expression, and synapse pruning in iCKO mice with 3-day tamoxifen treatment.

CONCLUSIONS

Preoperative BBB integrity influences the impact of anesthesia and surgery on the brain, with astrocytes modulating this effect. These findings partly explain the heterogeneity in the occurrence of postoperative brain homeostasis imbalance.

Acute changes in hippocampal metabolism after anesthesia and surgery: Implications for perioperative neurocognitive disorder

BACKGROUND

The risk of developing dementia is higher in individuals who suffer from perioperative neurocognitive disorder (PND), including postoperative cognitive dysfunction (POCD) and delirium. Recent studies have indicated correlations between anesthesia, surgery and PND. Acute metabolic changes induced by anesthesia and surgery may be related to cognitive impairments. Despite a paucity of research on acute metabolic changes in the hippocampus during surgery, there are conflicting about specific metabolites.

METHODS

We developed a mouse model of cognitive impairment induced by isoflurane anesthesia and unilateral nephrectomy. Cognition was evaluated by Y maze and fear conditioning test (FCT). The hippocampus was harvested after the surgery. LC-MS (liquid chromatography-mass spectrometry) was performed. The differential metabolites involved in lipid, amino acid, nucleotide, carbohydrate metabolism were analyzed.

RESULTS

Anesthesia and surgery exposure induced cognition decline. A total of 49 metabolites were significantly up-regulated and 122 down-regulated. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway of the metabolites identified purine, glutathione, nicotinate and nicotinamide metabolism. Metabolites involved in lipid, amino acid, nucleotide, carbohydrate metabolism were identified including nicotinamide adenine dinucleotide (NAD), 1-Methylnicotinamide, propionic acid, histidine, adenosine, and guanosine cyclic monophosphate. Some metabolites exhibited a consistent change trend in the hippocampus of aging mice.

CONCLUSIONS

The study indicates that anesthesia and surgery can induce acute alterations in hippocampal metabolomics, including metabolites involved in lipid, amino acid, nucleotide, and carbohydrate metabolism. These metabolites may play a role in modulating PND through the regulation of neuroinflammation, oxidative stress, blood-brain barrier (BBB) permeability.

Association of preoperative to postoperative change in cerebrospinal fluid fibrinogen with postoperative delirium

Background

We aimed to assess perioperative changes in fibrinogen in the cerebrospinal fluid (CSF), their association with markers of blood-brain barrier breakdown and neuroinflammation, and their association with postoperative delirium severity.

Methods

We conducted a secondary analysis of the Interventions for Postoperative Delirium-Biomarker 2 (IPOD-B2, NCT02926417) study, a prospective observational cohort study. We included 24 patients aged >21 yr undergoing aortic aneurysm repair. CSF samples were obtained before (n=24) and after surgery (n=13), with some participants having multiple postoperative samples. Our primary outcome was the perioperative change in CSF fibrinogen. Delirium was assessed using the Delirium Rating Scale-Revised-98.

Results

CSF fibrinogen increased after surgery (P<0.001), and this was associated with an increase in CSF/plasma albumin ratio (β=1.09, 95% CI 0.47-1.71, P=0.004). The peak change in CSF fibrinogen was associated with the change in CSF interleukin (IL)-10 and IL-12p70. The peak change in CSF fibrinogen was associated with the change in CSF total tau (β=0.47, 95% CI 0.24-0.71, P=0.002); however, we did not observe an association with postoperative delirium severity (incidence rate ratio = 1.20, 95% CI 0.66-2.17, P=0.540).

Conclusions

Our preliminary findings support the hypothesis that fibrinogen enters the brain via blood-brain barrier disruption, promoting neuroinflammation and neuronal injury. However, we did not observe an association between cerebrospinal fluid fibrinogen and peak delirium severity in this limited cohort.

Exploring molecular mechanisms of postoperative delirium through multi-omics strategies in plasma exosomes

Currently, the diagnosis of delirium is solely based on clinical observation, lacking objective diagnostic tools, and the regulatory networks and pathological mechanisms behind it are not yet fully understood. Exosomes have garnered considerable interest as potential biomarkers for a variety of illnesses. This research aimed to delineate both the proteomic and metabolomic landscapes inherent to exosomes, assessing their diagnostic utility in postoperative delirium (POD) and understanding the underlying pathophysiological frameworks. Integrated analyses of proteomics and metabolomics were conducted on exosomes derived from plasma of individuals from both the non-postoperative delirium (NPOD) control group and the POD group. Subsequently, the study utilized the Connectivity Map (CMap) methodology for the identification of promising small-molecule drugs and carried out molecular docking assessments to explore the binding affinities with the enzyme MMP9 of these identified molecules. We identified significant differences in exosomal metabolites and proteins between the POD and control groups, highlighting pathways related to neuroinflammation and blood-brain barrier (BBB) integrity. Our CMap analysis identified potential small-molecule therapeutics, and molecular docking studies revealed two compounds with high affinity to MMP9, suggesting a new therapeutic avenue for POD. This study highlights MMP9, TLR2, ICAM1, S100B, and glutamate as key biomarkers in the pathophysiology of POD, emphasizing the roles of neuroinflammation and BBB integrity. Notably, molecular docking suggests mirin and orantinib as potential inhibitors targeting MMP9, providing new therapeutic avenues. The findings broaden our understanding of POD mechanisms and suggest targeted strategies for its management, reinforcing the importance of multidimensional biomarker analysis and molecular targeting in POD intervention.

AI-Assisted Identification of Primary and Secondary Metabolomic Markers for Postoperative Delirium

Despite considerable investigative efforts, the molecular mechanisms of postoperative delirium (POD) remain unresolved. The present investigation employs innovative methodologies for identifying potential primary and secondary metabolic markers of POD by analyzing serum metabolomic profiles utilizing the genetic algorithm and artificial neural networks. The primary metabolomic markers constitute a combination of metabolites that optimally distinguish between POD and non-POD groups of patients. Our analysis revealed L-lactic acid, inositol, and methylcysteine as the most salient primary markers upon which the prediction accuracy of POD manifestation achieved AUC = 99%. The secondary metabolomic markers represent metabolites that exhibit perturbed correlational patterns within the POD group. We identified 54 metabolites as the secondary markers of POD, incorporating neurotransmitters such as gamma-aminobutyric acid (GABA) and serotonin. These findings imply a systemic disruption in metabolic processes in patients with POD. The deployment of gene network reconstruction techniques facilitated the postulation of hypotheses describing the role of established genomic POD markers in the molecular-genetic mechanisms of metabolic pathways dysregulation, and involving the identified primary and secondary metabolomic markers. This study not only expands the understanding of POD pathogenesis but also introduces a novel technology for the bioinformatic analysis of metabolomic data that could aid in uncovering potential primary and secondary markers in diverse research domains.

Desflurane versus sevoflurane anesthesia and postoperative recovery in older adults undergoing minor- to moderate-risk noncardiac surgery - A prospective, randomized, observer-blinded, clinical trial

STUDY OBJECTIVE

The effect of volatile anesthetics on postoperative recovery in older adults is still not entirely clear. Thus, we evaluated the effect of desflurane versus sevoflurane anesthesia on speed of postoperative recovery in older adults eligible for same-day discharge. We further evaluated the incidence of postoperative nausea and vomiting (PONV), bispectral index (BIS) values, and S100B concentrations.

DESIGN

Single-center, prospective, observer-blinded, randomized clinical trial.

SETTING

Operating room.

PATIENTS

190 patients ≥65 years of age and scheduled for minor- to moderate-risk noncardiac surgeries.

INTERVENTIONS

Goal-directed administration of desflurane versus sevoflurane for maintenance of anesthesia with an intraoperative goal of BIS 50 ± 5.

MEASUREMENTS

The primary outcome was the time to anesthesia recovery, which was defined as the time between arrival at the post-anesthesia care unit (PACU) and reaching criteria for discharge from PACU, based on modified Aldrete score ≥ 12 points. Modified Aldrete scores were assessed at PACU arrival and thereafter in five-minute intervals. PONV was evaluated during PACU stay and the first three postoperative days, BIS values were recorded during PACU stay, and S100B values were measured before and after surgery, and on the second postoperative day.

MAIN RESULTS

95 patients were randomized to receive desflurane, and 95 patients to receive sevoflurane. We did not observe a significant difference in median duration of postoperative recovery between the groups (desflurane: 0 min [0;0]; sevoflurane: 0 min [0;0]; p = 0.245). 77 patients (81.1%) in the desflurane group and 84 patients (88.4%) in the sevoflurane group already had Aldrete scores ≥12 points upon arrival at PACU (p = 0.277). There was also no significant difference in the incidences of PONV (p = 0.606), postoperative BIS values (p = 0.197), and postoperative maximum S100B concentrations (p = 0.821) between the groups.

CONCLUSIONS

Despite previous reports, we did not observe significant faster recovery times after desflurane anesthesia. Both volatile anesthetics may be appropriate for same-day discharge in older adults.

Serum Albumin Level at Intensive Care Unit Admission and Delirium Duration and Severity in Critically Ill Adults

BACKGROUND

Hypoalbuminemia has been associated with an increased risk of in-hospital delirium. However, the relationship between serum albumin levels and the duration and severity of delirium is not well defined.

OBJECTIVE

To investigate the relationship between albumin levels and delirium duration and severity.

METHODS

Study data were from a randomized controlled trial involving adult intensive care unit patients (≥ 18 years old) admitted to 3 academic hospitals from 2009 to 2015 who had positive delirium screening results on the Confusion Assessment Method for the Intensive Care Unit-7. Delirium severity was defined by mean Confusion Assessment Method for the Intensive Care Unit-7 scores by day 8. Delirum duration was defined by the number of delirium-free and coma-free days by day 8. Serum albumin levels within 72 hours of intensive care unit admission were collected from electronic medical records.

RESULTS

The study included 237 patients (mean age, 60.3 years; female sex, 52.7%; receiving mechanical ventilation, 59.5%; acute respiratory failure or sepsis, 57.8%). Serum albumin levels were categorized as 3 g/dL or greater (n = 13), 2.5 to 2.99 g/dL (n = 142), and less than 2.5 g/dL (n = 82). After adjustment for demographic and clinical characteristics, no significant associations between albumin levels and delirium duration or severity were found. However, patients with normal albumin levels (≥3 g/dL) had shorter stays than did patients with hypoalbuminemia.

CONCLUSION

In patients with delirium, higher albumin levels were associated with shorter hospital stays but not with delirium duration or severity.

Low blood S-methyl-5-thioadenosine is associated with postoperative delayed neurocognitive recovery

Elderly individuals display metabolite alterations that may contribute to development of cognitive impairment following surgery and anesthesia. However, these relationships remain largely unexplored. The study aims to assess the S-methyl-5-thioadenosine (MTA) is associated with postoperative delayed neurocognitive recovery (dNCR). We assess altered metabolites following anesthesia/surgery in both mice and patients to identify blood biomarkers of dNCR. Preoperative and postoperative plasma metabolites are determined by widely targeted metabolomics. The brains of mice with anesthesia/surgery show decreased MTA and activated MTA phosphorylase. Mice also show that preoperative administration of MTA can prevent inflammation and cognitive decline. In clinical patients, we detect lower preoperative serum MTA levels in those who developed dNCR. Both low preoperative and postoperative blood MTA levels are associated with increased risk of postoperative dNCR. These results suggest that anesthesia/surgery induces cognitive decline through methionine synthesis pathways and that MTA could be a perioperative predictor of dNCR.

Exploratory Randomised Trial of Tranexamic Acid to Decrease Postoperative Delirium in Adults Undergoing Lumbar Fusion: A trial stopped early

Background

Postoperative delirium may be mediated by perioperative systemic- and neuro-inflammation. By inhibiting the pro-inflammatory actions of plasmin, tranexamic acid (TXA) may decrease postoperative delirium. To explore this hypothesis, we modified an ongoing randomised trial of TXA, adding measures of postoperative delirium, cognitive function, systemic cytokines, and astrocyte activation.

Methods

Adults undergoing elective posterior lumbar fusion randomly received intraoperative intravenous TXA (n=43: 10 mg kg-1 loading dose, 2 mg kg-1 h-1 infusion) or Placebo (n=40). Blood was collected pre- and at 24 h post-operatively (n=32) for biomarkers of systemic inflammation (cytokines) and astrocyte activation (S100B). Participants had twice daily delirium assessments using the 3-minute diagnostic interview for Confusion Assessment Method (n=65). Participants underwent 4 measures of cognitive function preoperatively and during post-discharge follow-up.

Results

Delirium incidence in the TXA group (7/32=22%) was not significantly less than in the Placebo group (11/33=33%); P=0.408, absolute difference=11%, relative difference=33%, effect size = -0.258 (95% CI -0.744 to 0.229). In the Placebo group (n=16), delirium severity was associated with the number of instrumented vertebral levels (P=0.001) and with postoperative interleukin -8 and -10 concentrations (P=0.00008 and P=0.005, respectively) and these associations were not significantly modified by TXA. In the Placebo group, delirium severity was associated with S100B concentration (P=0.0009) and the strength of the association was decreased by TXA (P=0.002).

Conclusions

A potential 33% relative decrease in postoperative delirium incidence justifies an adequately powered clinical trial to determine if intraoperative TXA decreases delirium in adults undergoing lumbar fusion.

Effect of intravenous versus inhaled anesthetics on blood-brain barrier dysfunction and neuroinflammation in elderly patients undergoing major surgery: study protocol of a randomized controlled trial

BACKGROUND

Postoperative cognitive dysfunction (POCD) is one of the major complications after surgery, with devastating clinical outcomes. Although POCD is a condition with a multifactorial pathophysiology, blood-brain barrier (BBB) dysfunction and neuronal injury have been shown to play a critical role, especially in the elderly. Previous studies have demonstrated that the choice of anesthetics affect BBB permeability and neuroinflammation. However, most studies are carried out on animals, with limited research undertaken on humans. Therefore, we will compare the effect of intravenous anesthetics and inhaled anesthetics on BBB dysfunction and the change of inflammatory markers after surgery.

METHODS

One hundred and fifty-four patients who are 60 years of age or older undergoing major surgery for more than 2 h will be randomly allocated to two anesthetics groups (intravenous, inhaled) in a 1:1 ratio. In the intravenous anesthetics group (group P), propofol will be infused with a target-controlled infusion (TCI) system throughout the entire surgery. In the inhaled anesthetics group (group G), bolus injection of propofol will be administered for loss of consciousness, and simultaneously sevoflurane will be initiated for the maintenance of anesthesia. The primary outcome is the change in serum S100 calcium binding protein β (S100β) at four time points: before induction of anesthesia, at the end of surgery, 4 h after surgery, postoperative day 1. Secondary outcomes include changes in the inflammatory markers, serum interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-α, and C-reactive protein; the incidence of delirium; and the change in the cognitive function between groups. In patients pre-scheduled for postoperative intensive care unit admission, the cerebrospinal fluid/serum albumin quotient (Qalb) between the two groups will be compared before and after surgery, and change in inflammatory markers in serum and CSF will be analyzed in relation to the Qalb.

DISCUSSION

The current study will compare the effect of intravenous versus inhaled anesthetics on blood-brain barrier permeability and, as a result, the difference in neuroinflammation in elderly patients. Also, the study results will provide additional information to develop intraoperative anesthetic strategies to reduce POCD.

TRIAL REGISTRATION

The trial was prospectively registered at Clinical Trials protocol registration with identifier 2310-117-126 on April 9, 2024.

Exploring the Neural Mechanisms of Mirrored-Self Misidentification in Alzheimer's Disease

OBJECTIVE

Alzheimer's disease (AD) is a complex neurodegenerative condition that causes a range of cognitive disturbances, including mirror-self misidentification syndrome (MSM), in which patients cannot recognize themselves in a mirror. However, the mechanism of action of MSM is not precisely known. This study aimed to explore the possible neural mechanisms of action of MSM in AD using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).

METHODS

This study included 48 AD patients, 13 in the MSM group and 35 in the non-MSM group. The permeability of the blood-brain barrier (BBB) was quantitatively monitored by measuring the transfer rate (Ktrans) of the contrast agent from the vasculature to the surrounding tissue using DCE-MRI. The concentration of contrast agents in different brain regions was measured, and the Patlak model was used to calculate Ktrans. Ktrans values were compared between the left and right cerebral hemispheres in different brain areas between the MSM and non-MSM groups. Additionally, the difference in Ktrans values between mild and severe MSM was assessed. Logistic regression analysis was used to examine the risk factors for MSM.

RESULTS

The Mann‒Whitney U test was used to compare two groups and revealed elevated Ktrans values in the left thalamus, left putamen, left globus pallidus, left corona radiata, and right caudate in the MSM group (p < 0.05). Logistic regression analysis revealed that increased Ktrans values in the left putamen (OR = 1.53, 95% CI = 1.04, 2.26) and left globus pallidus (OR = 1.54, 95% CI = 1.02, 2.31) may be risk factors for MSM. After dividing MSM patients into mild and moderate-severe groups, the Ktrans values of the thalamus in the moderate-severe group were greater than those in the mild group (p < 0.05).

CONCLUSION

Our study revealed the relationship between BBB permeability and MSM in AD. MSM is associated with BBB breakdown in the left putamen and globus pallidus. The left putamen and globus pallidus may function in mirror self-recognition. Higher BBB permeability in the thalamus may reflect the severity of AD in MSM.

Effect of intranasal insulin on perioperative cognitive function in older adults: a randomized, placebo-controlled, double-blind clinical trial

BACKGROUND

Postoperative cognitive impairment are common neural complications in older surgical patients and exacerbate the burden of medical care on families and society.

METHODS

A total of 140 older patients who were scheduled for elective orthopaedic surgery or pancreatic surgery with general anaesthesia were randomly assigned to Group S or Group I with a 1:1 allocation. Patients in Group S and Group I received intranasal administration of 400 μL of normal saline or 40 IU/400 μL of insulin, respectively, once daily from 5 minutes before anaesthesia induction until 3 days postoperatively. Perioperative cognitive function was assessed using the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment-Basic (MoCA-B) at 1 day before and 3 days after surgery and postoperative delirium (POD) incidence was assessed using the 3-minute Diagnostic Interview for CAM (3D-CAM) on postoperative days 1-3. Serum levels of interleukin-6 (IL-6), tumour necrosis factor α (TNF-α), S100-β and C-reactive protein (CRP) were measured on the first day after surgery.

RESULTS

Insulin treatment significantly increased postoperative MMSE and MoCA-B scores in group I than in group S (P < 0.001, P = 0.001, respectively), decreased the incidence of POD within the 3-day postoperative period in Group I than in Group S (10.9% vs 26.6%, P = 0.024), and inhibited postoperative IL-6 and S100-β levels in Group I compared to Group S (P = 0.034, P = 0.044, respectively).

CONCLUSIONS

Intranasal insulin administration is thus suggested as a potential therapy to improve postoperative cognition in older patients undergoing surgery. However, a more standardized multi-centre, large-sample study is needed to further validate these results.

The Thalamus in Perioperative Neurocognitive Disorders

Thalamus function and structure are known predictors of individual differences in the risk of age-related neurocognitive disorders (NCD), such as dementia. However, to date, little is known about their role in the perioperative setting. Here, we provide a narrative review of brain-imaging studies of preoperative and postoperative thalamus scanning parameters associated with risks of developing perioperative NCD, such as postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) during the postoperative phase. These findings are discussed in light of the concept of reserve capacity.

Association between surgical admissions, cognition, and neurodegeneration in older people: a population-based study from the UK Biobank

BACKGROUND

Previous studies have shown that major surgical and medical hospital admissions are associated with cognitive decline in older people (aged 40-69 years at recruitment), which is concerning for patients and caregivers. We aimed to validate these findings in a large cohort and investigate associations with neurodegeneration using MRI.

METHODS

For this population-based study, we analysed data from the UK Biobank collected from March 13, 2006, to July 16, 2023, linked to the National Health Service Hospital Episode Statistics database, excluding participants with dementia diagnoses. We constructed fully adjusted models that included age, time, sex, Lancet Commission dementia risk factors, stroke, and hospital admissions with a participant random effect. Primary outcomes were hippocampal volume and white matter hyperintensities, both of which are established markers of neurodegeneration, and exploratory analyses investigated the cortical thickness of Desikan-Killiany-Tourville atlas regions. The main cognitive outcomes were reaction time, fluid intelligence, and prospective and numeric memory. Surgeries were calculated cumulatively starting from 8 years before the baseline evaluation.

FINDINGS

Of 502 412 participants in the UK Biobank study, 492 802 participants were eligible for inclusion in this study, of whom 46 706 underwent MRI. Small adverse associations with cognition were found per surgery: reaction time increased by 0·273 ms, fluid intelligence score decreased by 0·057 correct responses, prospective memory (scored as correct at first attempt) decreased (odds ratio 0·96 [95% CI 0·95 to 0·97]), and numeric memory maximum correct matches decreased by 0·025 in fully adjusted models. Surgeries were associated with smaller hippocampal volume (β=-5·76 mm³ [-7·89 to -3·64]) and greater white matter hyperintensities volume (β=100·02 mm³ [66·17 to 133·87]) in fully adjusted models. Surgeries were also associated with neurodegeneration of the insula and superior temporal cortex.

INTERPRETATION

This population-based study corroborates that surgeries are generally safe but cumulatively are associated with cognitive decline and neurodegeneration. Perioperative brain health should be prioritised for older and vulnerable patients, particularly those who have multiple surgical procedures.

FUNDING

The Australian and New Zealand College of Anaesthetists (ANZCA) Foundation and the University of Sydney.

Effects of intraoperative body temperature, blood pressure, cerebral tissue oxygenation, and anesthesia type on postoperative cognitive functions in geriatric arthroplasty surgery for hip fracture

OBJECTIVES

This study aimed to explore the effects of cerebral oxygenation, body temperature, hemodynamic changes, and anesthesia type on postoperative cognitive dysfunction (POCD) in geriatric patients undergoing hip fracture surgery.

PATIENTS AND METHODS

One hundred five elderly patients (59 males, 46 females; mean age: 76.7±8.8 years; range, 65 to 95 years) who were scheduled for hip fracture surgery under general or spinal anesthesia between March 2021 and March 2023 were enrolled in the prospective observational study. The cognitive functions were evaluated using the Mini-Mental State Examination (MMSE). Postoperative MMSE values <24 were considered indicative of POCD. Cerebral oxygenation was evaluated before and during the operation using near-infrared spectroscopy (NIRS), and body temperature was measured using a tympanic thermometer, with values <36℃ considered hypothermia. The relationship between decreases in blood pressure ≥30% and POCD was investigated. The relationship between decreases in NIRS of 25% and POCD was also investigated.

RESULTS

Postoperative cognitive dysfunction was observed in 29 (27.25%) of the 105 patients. The MMSE value was 24 in 67.06% of 29 patients, and all these patients developed POCD. The incidence of POCD in patients with a preoperative MMSE1 score of 30 was 12.30% (p=0.001). No relationship was identified between MMSE changes and anesthesia type, hypotension, and decreases in the NIRS (p=0.439, p=0.399). Hypothermia was found to be significantly related to POCD (p=0.013). The degree of hypothermia decreased the postoperative MMSE value at different rates. A 1°C body temperature decrease caused a 16.7%, 44.4%, and 50% decrease in MMSE scores of one, one, and two patients, respectively.

CONCLUSION

Hypothermia was found to be significantly related to POCD. The same degree of hypothermia caused different MMSE changes. Since the number of patients with POCD was very low, the effect of amounts of body temperature changes on clinically significant MMSE changes could not be supported by logistic regression. The preoperative MMSE values, MMSE change rates, and age were found to be effective in POCD. Maintaining the body temperature throughout the operation will ensure the preservation of postoperative cognitive functions.

Blood-brain barrier disruption: a culprit of cognitive decline?

Cognitive decline covers a broad spectrum of disorders, not only resulting from brain diseases but also from systemic diseases, which seriously influence the quality of life and life expectancy of patients. As a highly selective anatomical and functional interface between the brain and systemic circulation, the blood-brain barrier (BBB) plays a pivotal role in maintaining brain homeostasis and normal function. The pathogenesis underlying cognitive decline may vary, nevertheless, accumulating evidences support the role of BBB disruption as the most prevalent contributing factor. This may mainly be attributed to inflammation, metabolic dysfunction, cell senescence, oxidative/nitrosative stress and excitotoxicity. However, direct evidence showing that BBB disruption causes cognitive decline is scarce, and interestingly, manipulation of the BBB opening alone may exert beneficial or detrimental neurological effects. A broad overview of the present literature shows a close relationship between BBB disruption and cognitive decline, the risk factors of BBB disruption, as well as the cellular and molecular mechanisms underlying BBB disruption. Additionally, we discussed the possible causes leading to cognitive decline by BBB disruption and potential therapeutic strategies to prevent BBB disruption or enhance BBB repair. This review aims to foster more investigations on early diagnosis, effective therapeutics, and rapid restoration against BBB disruption, which would yield better cognitive outcomes in patients with dysregulated BBB function, although their causative relationship has not yet been completely established.

Effects of esketamine on postoperative negative emotions and early cognitive disorders in patients undergoing non-cardiac thoracic surgery: A randomized controlled trial

STUDY OBJECTIVE

To investigate whether a single dosage of esketamine injection in the anesthesia period could improve postoperative negative emotions and early cognitive function in patients undergoing non-cardiac thoracic surgery.

DESIGN

A prospective single center double blinded randomized placebo-controlled trial.

SETTING

Perioperative period; operating room, post anesthesia care unit and hospital ward.

PATIENTS

129 adult patients that underwent elective non-cardiac thoracic surgery under general anesthesia.

INTERVENTIONS

During the operation, pharmacologic prevention of postoperative negative emotion and early cognitive disorder with 0.2 mg/kg (Low esketamine group) and 0.5 mg/kg esketamine (High esketamine group) vs. placebo.

MEASUREMENTS

Emotion and early cognitive performance were assessed on the day before surgery (POD-1), postoperative day 1 (POD1) and day 3 (POD3) using HADS-A, HADS-D, Pain Visual Analogue Scale (VAS), Confusion Assessment Method (CAM), Mini-Mental State Examination (MMSE), and serum biomarkers (S100β, BDNF, IL-6, acetylcholine, and norepinephrine).

MAIN RESULTS

The high esketamine group showed significantly lower HADS-A and HADS-D scores than control group on POD1 and POD3. No significant differences were observed between the low esketamine group and the control group. The esketamine-treated groups showed lower pain VAS scores than the control group at 2 h and on the first day after operation. There were no significant differences among the three groups in CAM and MMSE scores. However, the high esketamine group had lower S100β and IL-6 levels, and higher BDNF levels postoperatively, while serum acetylcholine and norepinephrine were not significantly different.

CONCLUSIONS

A single intraoperative injection of 0.5 mg/kg esketamine can alleviate postoperative anxiety, depression, and pain to some extent. Although cognitive function behavioral evaluation did not show obvious benefits, it can also reduce the production of pro-inflammatory and brain injury-related factors while promoting the generation of brain-derived neurotrophic factor. Registration Trial registry: http://www.chictr.org.cn/; Identifier: ChiCTR2100047067.

Geriatric nutritional risk index predicts postoperative delirium in elderly: A meta-analysis

OBJECTIVES

To review current evidence on using the geriatric nutritional risk index (GNRI) in predicting postoperative delirium (POD) in elderly patients.

METHODS

The literature search was performed in core databases to include all the cohort studies on the association between GNRI and risk of POD for further meta-analysis.

RESULTS

A total of 6 studies with 4242 patients underwent this meta-analysis, which showed that the risk of POD was higher in patients with moderate and high GNRI than the ones with low GNRI (odds ratio [OR]=2.04, 95% confidence interval [CI] [1.58, 2.64], p<0.001), and moderate and high GNRI significantly increased the risk of POD in patients of 60 to 75 years or above [OR=1.98, 95%CI (1.49, 2.62), p<0.001; OR=2.79, 95%CI (1.38, 5.64), p=0.004, respectively].

CONCLUSION

Therefore, moderate and high GNRI increased the risk of POD in elderly patients.

Cognitive dysfunction in older patients undergoing non-neurosurgery in the immediate postoperative period: A systematic review

AIM

To explore the risk factors associated with postoperative cognitive dysfunction in older patients within the first 7 days after non-neurosurgical surgery and anaesthesia.

DESIGN

A systematic review.

METHODS

Following, PRISMA 2020 (Preferred Reporting Items for Systematic Reviews and Meta-analyses). Checklist, a systematic review of studies published from January 2018 to January 2024. The literature search was conducted across six electronic online databases, including PubMed, EMBASE, Scopus, Ovid, MEDLINE and Science Direct, and the Johns Hopkins Nursing Evidence-Based Practice Evidence Rating Scale was used for study appraisal.

RESULTS

The initial search yielded 1750 studies. The review included 19 studies which comprised prospective observational, case-control and retrospective studies. The prevalence of postoperative cognitive dysfunction ranged from 19% to 64% among older adults undergoing non-neurosurgery. The identified risk factors were classified into three phases including preoperative, intraoperative and postoperative. Preoperative risk factors were found in age, educational attainment, malnutrition, preoperative biomarkers and co-morbidities. Intraoperative risk factors were the duration of the operation, blood loss during the operation and anaesthesia used. Postoperative risk factors consisted of postoperative biomarkers and postoperative pain.

PATIENT OR PUBLIC CONTRIBUTION

The result from this review may assist researchers and healthcare providers in assessing the underlying causes and risk factors of postoperative cognitive dysfunction, and in formulating suitable preventative and therapeutic strategies for older adults with non-neurosurgery during the short-term postoperative period.

Correlation of preoperative inflammatory factors and emotional disorders with postoperative delirium in patients with craniocerebral trauma

BACKGROUND

Traumatic brain injury (TBI) imposes a substantial societal and familial burden due to its high disability and fatality rates, rendering it a serious public health problem. Some patients with TBI have poor treatment outcomes and are prone to postoperative delirium (POD), which affects their quality of life. Anxiety has been linked to increased POD incidence in some studies, while others have found no correlation.

AIM

To investigate the correlation of POD risk factors, preoperative inflammatory factors, and mood disorders in patients with TBI.

METHODS

We retrospectively collected data on the treatment of 80 patients with TBI from November 2021 to September 2023. Patients were grouped as POD and non-POD, according to their POD status, and the general data of the two groups were compared. Inflammatory factor levels were detected preoperatively, and the Hamilton Depression Scale (HAMD) and Hamilton Anxiety Scale (HAMA) were used to investigate the risk factors associated with POD in these patients. Logistic regression was used to identify the independent risk factors.

RESULTS

Twenty-one patients (26.25%) developed POD, including 7, 10, and 4 cases of the excitatory, inhibitory, and mixed types, respectively. There were 59 cases (73.75%) in the non-POD group. Compared with the non-POD group, the POD group had a significantly higher proportion of patients with low Glasgow Coma Scale (GCS) scores before admission, unilateral mydriasis, preoperative hemorrhagic shock, intraventricular hemorrhage (IVH), and postoperative hyperglycemic hyperosmolar disease (P < 0.05). In the POD group, interleukin-6 (IL-6), human tumor necrosis factor-α (TNF-α), myeloperoxidase levels, HAMA, and HAMD scores were higher than those in the non-POD group (all P < 0.05). Logistic multivariate analysis showed that GCS score at admission, IVH, IL-6, TNF-α, HAMA, and HAMD were independent risk factors for POD in patients with TBI (P < 0.05).

CONCLUSION

Low GCS score at admission, IVH, elevated IL-6 and TNF-α, other inflammatory indicators, anxiety, and depression, can increase the risk of POD in patients with TBI after surgery.