Postoperative neurocognitive disorders: A clinical guide

Advances in research on the pathogenesis and signaling pathways associated with postoperative delirium (Review)

Postoperative delirium (POD) is a common postoperative complication, characterized by acute, transient and fluctuating declines in consciousness and attention, with an incidence that increases with age. POD is associated with various adverse postoperative outcomes, including prolonged hospital stays, higher medical costs and increased morbidity and mortality rates. Moreover, it has been suggested that POD, as an early manifestation of postoperative cognitive impairment, may serve as a precursor to long‑term cognitive dysfunction. Given its considerable clinical impact, the prevention and management of POD are of critical importance. However, the mechanisms underlying POD remain insufficiently understood. Current hypotheses primarily implicate neuroinflammation, oxidative stress, neurotransmitter dysregulation and pathological protein changes, such as β‑amyloid deposition and tau hyperphosphorylation. Disruptions in the sleep‑wake cycle, electroencephalographic burst suppression, the microbiota‑gut‑brain axis, the olfactory‑brain axis and genetic susceptibility to delirium may also contribute to POD occurrence. Multiple signaling pathways are involved in POD, including the Wnt/β‑catenin, PI3K/AKT, brain‑derived neurotrophic factor/tropomyosin receptor kinase B, toll‑like receptor and NF‑κB pathways. These findings not only elucidate potential mechanisms but also highlight essential therapeutic targets and theoretical foundations for clinical management. However, due to the complexity and multifactorial nature of the pathogenesis of POD, no comprehensive or widely accepted clinical measures have yet been established for its prevention and treatment. Both non‑pharmacological and pharmacological interventions have a role in POD prevention and treatment. Non‑pharmacological strategies are currently prioritized, such as cognitive training, the Hospital Elder Life Program and comprehensive geriatric assessment. Pharmacological interventions include dexmedetomidine, melatonin and non‑steroidal anti‑inflammatory drugs, with intranasal insulin emerging as a promising preventive approach. Additionally, anesthesia management strategies, including depth of anesthesia monitoring, blood pressure regulation and multimodal postoperative analgesia, have also been recognized as effective measures for reducing the risk of POD. The present review provides a comprehensive overview of the pathogenesis of POD, relevant signaling pathways and available preventive and therapeutic strategies. By deepening the understanding of POD, the present review aims to offer practical guidance for clinicians in optimizing prevention and management approaches.

Association Between Allostatic Load and Delirium in ICU Patients: A Retrospective Analysis of the MIMIC-IV Database

Background: Allostatic load reflects the cumulative physiological effects of chronic and repeated stress on the body and is associated with dysregulation of multiple systems. This study aimed to examine the association between the allostatic load score (ALS) and the development of delirium in intensive care unit (ICU) patients. Method: The adult patients from the Medical Information Mart for Intensive Care (MIMIC-IV) database were screened and included in this study. Allostatic load was scored by hemoglobin A1c, high-density lipoprotein, total cholesterol, systolic blood pressure, diastolic blood pressure, body mass index, C-reactive protein, and serum albumin, and varied from 0 to 8. Restricted cubic spline and multivariate logistic regression were used to assess the relationship between ALS and delirium risk in the ICU. The threshold of the ALS was determined by the decision tree approach. A sensitivity analysis was also conducted. Results: A total of 656 patients were included in the study, and the incidence of delirium was 50.6% (n = 332). In a fully adjusted restricted cubic spline model, an increase in ALS was linearly positively correlated with the occurrence of delirium in the ICU (p-overall = 0.039, p-nonlinear = 0.506). The threshold for ALS was determined to be 3. ALS ≥ 3 was associated with increased delirium rates (p < 0.001), longer hospital stays (p < 0.001), and higher in-hospital mortality (p = 0.002). Subgroup analyses revealed no significant interactions (all p values for interactions > 0.05). Conclusions: Higher ALS was linearly associated with increased risk of ICU delirium. An ALS ≥ 3 identified patients with greater delirium incidence, longer hospital stays, and higher mortality.

Advancing electroencephalography education in anesthesiology

PURPOSE OF REVIEW

Electroencephalography (EEG) monitoring is a powerful tool for optimizing anesthesia depth and improving perioperative neurocognitive outcomes. Despite its potential, EEG adoption remains limited in anesthesiology due to training gaps, perceived complexity, and reliance on processed EEG indices. This review examines current educational strategies and highlights the need for structured EEG education in anesthesia training.

RECENT FINDINGS

Emerging educational methodologies include short, focused teaching sessions, electronic learning modules, simulation-based practice, real-time clinical application with feedback, and self-directed study resources. Deliberate practice, spaced repetition, and competency-based progression have shown significant promise in improving EEG interpretation skills among anesthesiologists. Research remains sparse, but existing evidence indicates that even brief, structured interventions can meaningfully enhance clinical proficiency.

SUMMARY

Structured, accessible EEG training programs are critical to demystifying EEG interpretation and integrating its use into standard anesthetic practice. Embedding EEG education into residency curricula by relying on modern educational techniques and promoting faculty development will be essential to ensure anesthesiologists are equipped to use EEG monitoring effectively, ultimately improving patient outcomes.

Impact of perioperative esketamine on the perioperative neurocognitive dysfunction: a systematic review and meta-analysis of randomised controlled studies

OBJECTIVES

The effect of esketamine on perioperative neurocognitive dysfunction (PND) remains controversial. This systematic review and meta-analysis aimed to evaluate the impact of perioperative esketamine administration on PND.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, EMBASE, Web of Science and Cochrane Library were searched from their inception to 25 April 2024.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

We included the randomised controlled trials (RCTs) that compared single or continuous intravenous infusion of esketamine to saline among adult surgical patients without pre-existing neurocognitive disorders.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently extracted pertinent information from the included studies. Risk of bias was assessed using Cochrane's risk of bias criteria. Risk ratios (RRs) and their corresponding 95% CIs were synthesised using a random-effects model. The overall evidence quality was appraised using the Grading of Recommendations Assessment, Development and Evaluation framework.

RESULTS

10 RCTs were included in our meta-analysis, involving 854 surgical patients. Perioperative esketamine was associated with a reduced risk of postoperative delirium (POD) (relative risk (RR): 0.46, 95% CI: 0.30 to 0.71, p<0.001) and delayed neurocognitive recovery (dNCR) (RR: 0.41, 95% CI: 0.21 to 0.78, p<0.001). However, no statistically significant difference was found in the risk of postoperative neurocognitive disorder (post-NCD) at 3 months postsurgery between the esketamine and control groups (RR: 0.57, 95% CI: 0.19 to 1.73, p=0.40). Additionally, pain severity was reduced on postoperative day 1, with no difference in the risk of adverse events or length of hospital stay.

CONCLUSION

Perioperative esketamine reduces the risk of short-term PND, including POD and dNCR, without significantly affecting the incidence of adverse events or length of hospital stay. However, no significant differences were observed in the risk of post-NCD at 3 months following surgery. This systematic review and meta-analysis offers valuable data for PND research and clinical drug intervention strategies.

PROSPERO REGISTRATION NUMBER

CRD42024538438.

Brain-targeted goal-directed therapy in high-risk patients undergoing major elective surgery: Study protocol for the BRAIN-PROMISE randomized trial

BACKGROUND

Perioperative complications can lead to increased morbidity and mortality, diminished patient's quality of life, and substantial economic burden. Elderly and frail patients are particularly vulnerable, facing higher risks of postoperative cognitive dysfunction and delirium. Perioperative choices and anaesthesia management, including hemodynamic monitoring, anaesthesia depth, and fluid therapy can significantly impact long-term outcomes. Near-infrared spectroscopy (NIRS) is a technique for measuring regional oxygen saturation of brain tissue (rSO2) during surgery. Monitoring cerebral perfusion through rSO2 could estimate perfusion changes, identify early tissue hypoxia, and mitigate postoperative complications. Nonetheless, there is a lack of studies exploring NIRS-based hemodynamic optimization protocols in high-risk surgical populations.

OBJECT

This prospective randomized controlled trial has been designed to evaluate whether NIRS-targeted goal-directed therapy can reduce rSO2 drop episodes and improve outcomes in high-risk elderly patients undergoing major surgery.

METHODS

This randomized controlled trial will enroll hypertensive elderly patients aged ≥65 or with a clinical frailty score ≥ 5, undergoing moderate to high-risk surgery under general anaesthesia. Participants will be randomized 1:1 to either NIRS-targeted management or standard care, with NIRS monitoring applied to both groups but only guiding intervention in the experimental group, and with anesthesiologist blinded to NIRS value in control group. Primary outcomes include the overall incidence of perioperative complications at 30 days, secondary outcomes assess cognitive dysfunction, delirium, length of stay and mortality at 90 days.

CONCLUSIONS

This study presents an innovative approach on the effectiveness of NIRS-targeted goal directed for improving perioperative outcomes in high-risk elderly patients undergoing general anaesthesia.

TRIAL REGISTRATION

clinicaltrials.gov registration, n. NCT04266574.

Anaesthesia modality on endovascular therapy outcomes in patients with large infarcts: a post hoc analysis of the ANGEL-ASPECT trial

OBJECTIVES

Endovascular therapy (EVT) now penetrates the once obscure realm of large infarct core volume acute ischaemic stroke (LICV-AIS). This research aimed to investigate the potential correlation between different anaesthetic approaches and post-EVT outcomes in LICV-AIS patients.

METHODS

Between October 2020 and May 2022, the China ANGEL-Alberta Stroke Programme Early CT Score (ASPECT) trial studied patients with LICV-AIS, randomly assigning them to the best medical management (BMM) or BMM with EVT. This post hoc subgroup analysis categorised subjects receiving BMM with EVT into general anaesthesia (GA) and non-GA groups based on anaesthesia type. We applied multivariable logistic regression to evaluate the relationship between anaesthesia during EVT and patient functional outcomes, as measured by the modified Rankin scale (mRS), in addition to the occurrence of complications. Further adjustment for selection bias was achieved through propensity score matching (PSM).

RESULTS

In total, 230 patients with LICV-AIS were enrolled (GA 84 vs Non-GA 146). No significant difference was observed between the two groups in terms of the proportion of patients who achieved an mRS score of 0-2 at 90 days (27.4% for the GA group vs 31.5% for the non-GA group, p=0.51). However, the GA group had significantly longer median surgical times (142 min vs 122 min, p=0.03). Furthermore, GA was associated with an increased risk of postoperative pneumonia (adjusted OR 2.03, 95% CI 1.04 to 3.98). The results of PSM analysis agreed with the results of the multivariate regression analysis. No significant difference in intracranial haemorrhage incidence or mortality rate was observed between the groups.

CONCLUSION

This post hoc analysis of subgroups of the ANGEL-ASPECT trial suggested that there may be no significant association between the choice of anaesthesia and neurological outcomes in LICV-AIS patients. However, compared with non-GA, GA prolongs the duration of EVT and is associated with a greater postoperative pneumonia risk.

TRIAL REGISTRATION NUMBER

NCT04551664.

Role of modified enhanced recovery after surgery (mERAS) in awake craniotomy performed under monitored anesthesia care (MAC); a single center retrospective study

BACKGROUND

This study aims to explore the safety and efficacy of awake craniotomy procedures under monitored anesthesia care (MAC), focusing on the impact of modified Enhanced Recovery after Surgery (ERAS) protocols on patient outcomes.

METHODS

Patients undergoing elective awake craniotomy between 2017 and 2022 were divided into two groups: those receiving the ERAS protocol after 2020 and a control group of pre-2020 patients. Factors examined included demographics, intraoperative awakening time, procedure durations, pain management, hospital stay length, complications, discharge disposition, and follow-up symptoms.

RESULTS

From 2017 to 2022, 61 patients underwent awake craniotomy using MAC anesthesia at University Hospitals Cleveland Medical Center, with 23 receiving the ERAS protocol after 2020. Demographics were comparable between the control and ERAS groups. Total awake time, time to wake up, and total procedure time showed no significant differences (P > 0.05). Awake craniotomy was discontinued in 8 cases due to anxiety and pain (mERAS = 1, Control = 7). The mERAS group experienced fewer cases of awake failure, nausea/vomiting, and postoperative cognitive and speech deficits, though these differences were not statistically significant. No significant differences were found in postoperative pain medication consumption, complications, or length of hospital stay (P > 0.05).

CONCLUSIONS

Awake craniotomy under MAC with a modified ERAS protocol is feasible but did not show statistically significant improvements in patient outcomes. Further research with larger sample sizes and multi-center collaboration is necessary to draw more definitive conclusions.

The effect of neuromuscular blocking reversal agents on perioperative neurocognitive function after general anaesthesia: a systematic review and meta-analysis

BACKGROUND

Perioperative neurocognitive dysfunction (PND) is influenced by various perioperative factors. Recent studies suggest that neuromuscular blocking reversal agents (NMBRs) may impact on PND. However, the results have been inconsistent. Therefore, we aimed to compare the effects of perioperative NMBRs on PND through this systematic review and meta-analysis.

METHODS

We searched PubMed, CENTRAL, Embase, Web of Science, Scopus, and China Biology Medicine from their inception until May 2024. Two reviewers independently identified randomized controlled trials (RCTs) that compared the perioperative use of NMBRs with either a placebo or other NMBRs in patients undergoing general anaesthesia. We assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. The primary outcome was the incidence of PND within 7 days following surgery, while the secondary outcomes included the time required to achieve a Train-of-Four ratio (TOF) ≥ 0.9 after administration of NMBRs, length of stay (LOS) in both the post-anaesthesia care unit (PACU) and the hospital, as well as the risk of adverse events (i.e. postoperative nausea and vomiting (PONV) and mortality).

RESULTS

A total of 10 randomized controlled trials involving 1705 patients compared the effects of NMBRs on PND. Neostigmine and sugammadex are the most commonly used NMBRs in clinical anaesthesia practice. In the primary analyses of all regimens, sugammadex significantly reduced the incidence of PND compared to neostigmine (risk ratio [RR] 0.67; 95% confidence interval [CI]:0.48-0.94; I2 = 0%; P = 0.02; moderate quality). However, the results indicated that there is no significant association between neostigmine and PND when compared to placebo (RR 0.76; 95% CI: 0.55-1.05; I2 = 35%; P = 0.09; moderate quality). The secondary outcomes revealed that sugammadex could significantly shorten the time of TOF ≥ 0.9 compared to neostigmine (mean difference [MD] -4.52; 95%CI: -5.04 to -3.99; I2 = 80%; P < 0.01; Moderate quality). Furthermore, no significant differences were observed in the incidence of adverse events or hospital LOS.

CONCLUSIONS

This meta-analysis demonstrated that the use of sugammadex was associated with improved early perioperative neurocognitive function compared to neostigmine when used to reverse neuromuscular blockade, without an increase in the incidence of adverse events.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO CRD42024520287.

Hemoglobin to red cell distribution width ratio predicts postoperative delirium in older patients undergoing hip fracture surgery: A retrospective cohort study

AIM

This study aimed to investigate the predictive effect of hemoglobin to red cell distribution width ratio (HRR) on postoperative delirium (POD) in older patients undergoing hip fracture surgery.

METHODS

POD was diagnosed by capturing descriptive words from the medical records. The correlation between POD and HRR was determined using logistic regression analysis, and the receiver operating characteristic curve was used to further evaluate the value of HRR in predicting POD.

RESULTS

In total, 202 older patients accepting hip fracture surgery were included in our study. The result of multiple logistic regression analysis presented HRR (odds ratio, 0.504 [95% confidence interval, 0.340-0.747]; P < 0.001), American Society of Anesthesiologists physical status >2, and neutrophils were independently correlated with POD. The area under the curve of HRR was 0.746 (95% confidence interval, 0.676-0.815), and the optimal cutoff value was 8.322.

CONCLUSIONS

HRR, American Society of Anesthesiologists physical status >2 and neutrophils could independently predict POD in older patients undergoing hip fracture surgery, and HRR had satisfactory predictive value. However, further research is needed to confirm our findings. Geriatr Gerontol Int 2025; 25: 565-571.

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.

Preoperative Sleep Deprivation Exacerbates Anesthesia/Surgery-induced Abnormal GABAergic Neurotransmission and Neuronal Damage in the Hippocampus in Aged Mice

Older adults with anesthesia and surgery often suffer from postoperative cognitive dysfunction (POCD), which puts a heavy burden on rehabilitation. Preoperative sleep disorder, a common phenomenon in elderly anesthesia patients, is closely associated with POCD, but the underlying mechanism is still not fully understood. Hippocampal gamma-aminobutyric acid (GABA)ergic neurotransmission has been reported to play an important role in sleep disorder and cognitive impairment. The aim of this study was to elucidate the effect of preoperative acute sleep deprivation (SD) on anesthesia/surgery-induced POCD and the potential mechanism of hippocampal GABAergic neurotransmission. In the aged (18-20-month-old) male mice, we used a rotating rod to deprive sleep for 24 h and induced a POCD model using sevoflurane exposure combined with laparotomy exploration. A sequential set of behavioral tests, including open field test (OFT), Y-maze, and novel object recognition (NOR), was conducted to assess cognitive performances. In vivo magnetic resonance imaging (MRI) technique was used to observe hippocampal axonal microstructural changes. The levels of GABAergic neurotransmitter markers glutamic acid decarboxylase (GAD) 67, vesicular GABA transporter (VGAT), GABA transporter (GAT)-1, and GABA in the hippocampus were detected with enzyme-linked immunosorbent assay (ELISA). The reactivity of GABAergic neurons and neuronal damage in different subregions of the hippocampus were observed by immunofluorescence and Nissl staining, respectively. Compared the anesthesia/surgery (A/S) mice, 24-h SD combined with A/S induced shorter stay time in the central area of the open field, less the percent of novel arm preference in the Y maze, and lower recognition index in the NOR, as well as significantly enhanced hippocampal GABAergic neurotransmission, decreased hippocampal axonal integrity and density, and increased GAD67 reactivity and reduced the number of neurons in hippocampal CA1. Preoperative 24-h SD exacerbated anesthesia/surgery-induced POCD in aged mice, with the cumulative effect of abnormal GABAergic neurotransmission and neuronal damage in the hippocampus.

Development and validation comparison of multiple models for perioperative neurocognitive disorders during hip arthroplasty

This study aims to develop optimal predictive models for perioperative neurocognitive disorders (PND) in hip arthroplasty patients, thereby advancing clinical practice. Data from all hip arthroplasty patients in the MIMIC-IV database were utilized to predict PND. With 62 variables, we applied multiple logistic regression, artificial neural network (ANN), Naive Bayes, support vector machine, and decision tree (XgBoost) algorithms to forecast PND. Feature analysis, receiver operating characteristic curve (ROC) and calibration curve plotting, and sensitivity, specificity, and F-measure β = 1 (F1-score) assessments were conducted on both training and validation sets for classifying models' effectiveness. Brier score and Index of prediction accuracy (IPA) were employed to compare prediction capabilities in both sets. Among 3,292 hip arthroplasty patients in the MIMIC database, 331 developed PND. Five models using different algorithms were constructed. After thorough comparison and validation, the ANN model emerged as the most effective model. Performance metrics on the training set for the ANN model were: ROC: 0.954, Accuracy: 0.938, Precision: 0.758, F1-score: 0.657, Brier Score: 0.048, IPA: 90.8%. On the validation set, the ANN model performed as follows: ROC: 0.857, Accuracy: 0.903, Precision: 0.539, F1-score: 0.432, Brier Score: 0.071, IPA: 71.4%. An online visualization tool was developed ( https://xyyy.pythonanywhere.com/ ).

Postoperative neurocognitive disorders in the elderly: how can we stop the harm? A literature review

Postoperative neurocognitive disorders (PND) represent a significant challenge affecting patients undergoing surgical procedures, particularly in the elderly population. These disorders can lead to profound impairments in cognitive function, impacting memory, attention, and overall quality of life. Despite ongoing research efforts to identify risk factors and improve management strategies, PND remains underdiagnosed and poorly understood, complicating postoperative recovery and rehabilitation. This review aims to explore the recent advancement in the literature about PND, focusing on the underlying mechanisms, risk factors, and potential therapeutic approaches. We highlight recent advancements in the understanding of neuroinflammation, and it is implications for novel therapies to prevent PND. By synthesizing the latest research, we hope to provide insights that could lead to improved outcomes for patients at risk for PND and foster a shift towards more effective preventive measures in such population.

Effectiveness of perioperative remimazolam in preventing postoperative delirium: a systematic review and meta-analysis

BACKGROUND

To compare the POD rates in patients undergoing non-cardiac surgery who received remimazolam perioperatively versus placebo or other sedatives.

METHODS

We systematically searched four major databases (Cochrane Central Register of Controlled Trials, Web of Science, Embase, and PubMed) for relevant randomized controlled trials (RCTs) up to July 11, 2024. Literature quality evaluation was used the bias risk table in Review Manager 5.4. The primary outcome of interest was POD, and secondary outcomes were the hypotension risk, bradycardia and, nausea and vomiting.

RESULTS

Across 11 trials involving 1985 participants, we recorded 309 cases of POD during follow-up. In trials where the control group received saline, remimazolam decrease the risk of POD significantly by 70% (RR 0.30, 95% CI [0.19, 0.46]; p < 0.00001). Statistical analysis did not show significant difference in the risk of POD between the remimazolam group and the groups receiving either dexmedetomidine (RR 1.23 [0.64, 2.37]; p = 0.53) or propofol (RR 0.83 [0.60, 1.16]; p = 0.28). Regarding adverse events, remimazolam significantly reduces the morbidity of hypotension compared to dexmedetomidine (RR 0.25 [0.10, 0.65]; p = 0.004) and propofol (RR 0.45 [0.33, 0.60]; p < 0.00001). In addition, there were no significant differences in the incidence of bradycardia (RR 0.85; 95% CI [0.34-2.12], p = 0.72) and nausea and vomiting (RR 1.06; 95% CI [0.74-1.51], p = 0.77) between remimazolam and the control group.

CONCLUSIONS

During the perioperative period, using remimazolam can lower POD risk after surgery for patients who had non-cardiac surgery, but remimazolam does not work better than dexmedetomidine or propofol. Compared with the dexmedetomidine and propofol, remimazolam also has apparent advantages in preventing intraoperative hypotension.

Effect of combination of multiple anti-inflammatory drugs strategy on postoperative delirium among older patients undergoing hip fracture surgery: a pilot randomized controlled trial

BACKGROUND

Postoperative delirium is the most common complication in older patients and is associated with surgery-induced inflammation. Although inflammation plays a key role in delirium, the potential benefits of a comprehensive anti-inflammatory approach to managing perioperative systemic inflammation remain underexplored. This study evaluated whether a perioperative anti-inflammatory bundle strategy, combining dexmedetomidine, glucocorticoids, ulinastatin, and nonsteroidal anti-inflammatory drugs, reduces the risk of postoperative delirium in older patients undergoing hip fracture surgery.

METHODS

This dual-center, double-blind, placebo-controlled, parallel-group, pilot study was conducted from August 2023 to January 2024 at two tertiary university hospitals. A total of 132 patients aged ≥ 65 years with an American Society of Anesthesiologists physical status of 2 or 3 scheduled for elective hip fracture surgery were screened and randomized to receive either an anti-inflammatory drug bundle or a placebo. The primary outcome was postoperative delirium, identified within the first three postoperative days. Postoperative blood inflammatory markers and acute pain were measured for mediation analysis.

RESULTS

Of the 132 patients randomized, 123 (93%) completed the trial (mean age, 82 years; 75% women). The prevalence of postoperative delirium was significantly lower in the anti-inflammatory bundle group (15%, 9/62) compared to the placebo group (44%, 27/61) (risk difference, - 30 percentage points [95% CI, - 45 to - 15]; relative risk [RR], 0.33 [95% CI, 0.17 to 0.64]; P = 0.001). No major adverse events were reported in either group. The postoperative CRP level in the anti-inflammatory bundle group was significantly lower (predicted mean difference: - 29.4 [95% CI: - 46.5, - 12.2] mg·L-1; adjusted P < 0.001). Mediation analysis showed a significant indirect association between the anti-inflammatory bundle and postoperative delirium through reduced systemic inflammation (odds ratio [OR], 0.61 [95% CI, 0.26 to 0.87]).

CONCLUSIONS

This study demonstrates that a perioperative anti-inflammatory bundle significantly reduces the prevalence of postoperative delirium in older patients undergoing hip fracture surgery, without major side effects. Systemic inflammation mediates the protective effect of the intervention. These findings provide preliminary evidence supporting the anti-inflammatory bundle strategy, paving the way for large-scale multicenter trials to optimize postoperative delirium prevention strategies.

TRIAL REGISTRATION

This study was registered in the Chinese Clinical Trial Registry (ChiCTR2300074303) by Ayixia Nawan on August 3, 2023, prior to patient enrollment.

Environmental enrichment attenuates sevoflurane anesthesia-induced learning deficits in aged mice through regulating TTBK1 and phosphorylated Tau expression

Perioperative neurocognitive disorders (PND) are a prevalent complication in elderly patients undergoing surgery with general anesthesia. Sevoflurane, a commonly used anesthetic, has been associated with cognitive impairment and neurotoxicity. In this study, we aim to explore the mechanisms through which sevoflurane impairs cognitive function in aged mice and hence identify potential therapeutic strategies. Female C57BL/6 J mice were treated with 2-h-daily Environmental enrichment (EE) for 4 weeks before being exposed to single 3% sevoflurane plus 60% oxygen inhalation for 2 h. WHI-P180, a TTBK1 inhibitor, was administered 5 min prior to anesthesia. Cognitive function, TTBK1, Tau p-Ser422, AT8 (Tau p-Ser202/p-Thr205), TNF-ɑ, IL-6, and IL-1β were measured. The results indicated that sevoflurane inhalation induced cognitive dysfunction, elevated TTBK1 expression and phosphorylated Tau levels, and increased inflammatory factors in the hippocampus of aged mice. However, EE treatment reduced elevated TTBK1, phosphorylated Tau, and inflammatory factor levels in the hippocampus. Additionally, EE alleviated cognitive impairment caused by sevoflurane in aged mice. Furthermore, WHI-P180 mitigated cognitive dysfunction by decreasing Tau phosphorylation and inflammatory cytokine levels in the hippocampus of aged mice. In conclusion, TTBK1 plays a crucial role in cognitive impairment induced by sevoflurane in aged mice, and EE mitigates sevoflurane-induced cognitive dysfunction by inhibiting TTBK1 and Tau protein phosphorylation in the hippocampus of old mice. These findings suggest that EE could be a potential therapeutic strategy for preventing or treating PND in elderly patients undergoing general surgery with sevoflurane anesthesia.

Postoperative delirium under general anaesthesia by remimazolam versus propofol: A systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Remimazolam, an ultra-short-acting benzodiazepine, has similar clinical effects to propofol for sedation in general anaesthesia. However, it remains uncertain whether remimazolam could increase postoperative delirium (POD) compared with propofol.

OBJECTIVES

The purpose of our study was to compare the incidence of POD between remimazolam and propofol as sedative agents in general anaesthesia.

STUDY DESIGN

Systematic review and meta-analysis of randomised controlled trials (RCTs).

METHODS

PubMed, Embase, Cochrane Library, and Web of Science databases were searched for prospective RCTs published through September 16, 2024. RCTs reporting the incidence of POD and comparing remimazolam with propofol for general anaesthesia were included. Odds ratio (ORs) were calculated using a random-effects model. The primary outcome was the incidence of POD. The secondary outcomes included time to extubation, awakening time, and adverse events such as intraoperative hypotension.

RESULTS

A total of six RCTs involving 1107 patients were included in this meta-analysis. For the primary outcome, the incidence of POD did not differ between the remimazolam and propofol groups (OR, 0.92; 95 % confidence interval [CI], 0.58-1.44). Regarding the secondary outcomes, remimazolam was associated with a lower incidence of intraoperative hypotension compared with propofol (OR, 0.31; 95 % CI, 0.21-0.46). There were no significant differences in other secondary outcomes. In the sensitivity analysis on three RCTs including only older patients (≥60 years old), there was no significant difference in the incidence of POD (OR, 1.00; 95 % CI, 0.52-1.93).

CONCLUSION

Perioperative remimazolam administration did not increase POD and reduced the risk of intraoperative hypotension compared to propofol. Further large-scale RCTs are warranted to explore the association of remimazolam and POD. Systematic review protocol: PROSPERO CRD42024544122.

The Role of the Intestinal Flora and Its Derivatives in Neurocognitive Disorders: A Narrative Review from Surgical Perspective

Perioperative neurocognitive dysfunction is a significant concern for population health, impacting postoperative recovery and increasing the financial burden on patients. With an increasing number of surgical procedures being performed, the prevention and management of perioperative neurocognitive dysfunction have garnered significant attention. While factors such as age, lifestyle, genetics, and education are known to influence the development of cognitive dysfunction, recent research has highlighted the role of the gut microbiota in neurological health. An increased abundance of pro-inflammatory gut microbiota can trigger and worsen neuroinflammation, neuronal cell damage, and impaired cellular autophagy. Moreover, the inflammation-promoting gut microbiota can disrupt immune function, impair neuroautophagy, and affect the production and circulation of extracellular vesicles and neurotransmitters. These factors collectively play a role in the onset and advancement of cognitive impairment. This narrative review delves into the molecular mechanisms through which gut microbiota and their derivatives contribute to cognitive impairment, focusing on the impact of anesthesia surgery, changes in gut microbial populations, and perioperative cognitive impairment associations. The study suggests that alterations in the abundance of various bacterial species and their metabolites pre- and post-surgery may be linked to postoperative cognitive impairment. Furthermore, the potential of probiotics or prebiotics in addressing cognitive impairment is discussed, offering a promising avenue for investigating the treatment of perioperative neurocognitive disorders.

Intravenous dexmedetomidine for delirium prevention in elderly patients following orthopedic surgery: a meta-analysis of randomized controlled trials

OBJECTIVES

We conducted a meta-analysis to investigate the effect of dexmedetomidine on postoperative delirium in elderly orthopedic surgery patients.

METHODS

A meta-analysis was conducted to identify randomized controlled trials of dexmedetomidine in elderly patients undergoing orthopedic surgery. The data was published on October 25, 2024. PubMed, Embase, and Cochrane Library databases were searched. Outcome measures included incidence of delirium, length of hospital stay, visual analogue scale, and postoperative complications. Estimates are expressed as relative risk (RR) or mean difference (MD) with a 95% confidence interval (CI). The publications were reviewed according to the guidelines of the Cochrane Handbook and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

This study was registered with INPLASY (number INPLASY2024110004). A total of 3159 patients were included in 9 randomized controlled trials. The results showed that dexmedetomidine exhibited a preventive effect on delirium compared with the control group in elderly patients after orthopedic surgery (RR: 0.55, 95% CI: 0.45-0.66, P < 0.01, I2 = 0%). Subgroup analysis suggested that dexmedetomidine was significantly different from saline(RR: 0.56; 95% CI: 0.44-0.73, P<0.01, I²=31%) and propofol(RR: 0.52; 95% CI: 0.39-0.70, P<0.01, I²=0%) in reducing postoperative delirium in elderly fracture patients. No statistically significant differences were observed in length of hospital stay, visual analogue scale, and postoperative complications (P > 0.05). Certainty of evidence for postoperative delirium was moderate.

CONCLUSIONS

Dexmedetomidine has been shown to have a protective effect on postoperative delirium in elderly patients following orthopedic surgery.

Bibliometric Analysis of Neuroinflammation and Postoperative Cognitive Dysfunction

BACKGROUND

The occurrence and development of postoperative cognitive dysfunction (POCD) are closely linked to neuroinflammation. This bibliometric analysis aims to provide novel insights into the research trajectory, key research topics, and potential future development trends in the field of neuroinflammation-induced POCD.

METHODS

The Web of Science Core Collection (WoSCC) database was searched to identify publications from 2012 to 2023 on neuroinflammation-induced POCD. Bibliometric analysis, involving both statistical and visual analyses, was conducted using CiteSpace, VOSviewer, and the R software.

RESULTS

Research on neuroinflammation-induced POCD has exhibited an increasing trend over the past 12 years. China had the highest number of publications, Nanjing Medical University had the most collaboration with other institutions, Zhiyi Zuo was the most published author, and the Journal of Neuroinflammation served as the primary publication in the field of neuroinflammation-induced POCD. The most frequent keyword was POCD. Keyword clustering analysis indicated that the predominant cluster is dexmedetomidine. Burst detection revealed that postoperative delirium (POD), perioperative neurocognitive disorders (PND), apoptosis, and epigenetic modifications were the future research trends.

CONCLUSIONS

Our analysis identified the following key research areas associated with neuroinflammation-induced POCD: anesthesia, surgery, dexmedetomidine, NLRP3 inflammasome, and mechanism of neuroinflammation-induced POCD. The potential future research topics comprise POD, PND, apoptosis, and epigenetic modifications.

Current Progress on Postoperative Cognitive Dysfunction: An Update

Postoperative cognitive dysfunction (POCD) represents a significant clinical concern, particularly among elderly surgical patients. It is characterized by a decline in cognitive performance, affecting memory, attention, coordination, orientation, verbal fluency, and executive function. This decline in cognitive abilities leads to longer hospital stays and increased mortality. This review provides a comprehensive overview of the current progress in understanding the relevant pathogenic factors, possible pathogenic mechanisms, diagnosing, prevention and treatment of POCD, as well as suggesting future research directions. It discusses neuronal damage, susceptible genes, central cholinergic system, central nervous system (CNS) inflammation, stress response and glucocorticoids, and oxidative stress in the development of POCD, aiming to uncover the pathological mechanism and develop effective treatment strategies for POCD.

Preventive Effect of Hydroxyzine on Postoperative Nausea and Vomiting: A Single-Center, Retrospective, Observational Cohort Study

Background/Objectives: Postoperative nausea and vomiting (PONV) is a common and distressing complication after surgery. Hydroxyzine, an affordable histamine H1 receptor antagonist with anxiolytic, moderate sedative, and antiemetic properties, is often used perioperatively; however, few studies have investigated its effect on PONV. In this study, we examined the efficacy of hydroxyzine in preventing PONV. Methods: This single-center, retrospective, observational cohort study included 647 female patients at risk of PONV between July 2021 and September 2022. The primary endpoint was PONV incidence on the day of surgery, and secondary endpoints included PONV incidence up to postoperative day 2 and emergence time, analyzed using propensity score matching. Results: The patients were categorized into two groups: 71 received hydroxyzine 25 mg (HYD group), and 576 received no prophylactic antiemetic treatment (NOT group). After adjustment for confounders, PONV incidence on the day of surgery was significantly lower in the HYD (n = 69) group compared to the NOT (n = 193) group (34.8% vs. 57.0%, p = 0.002), and similar results were observed up to postoperative day 2 (47.8% vs. 65.3%, p = 0.016). Emergence time did not differ between groups. Conclusions: Prophylactic administration of hydroxyzine could be effective in decreasing PONV incidence, though further randomized controlled trials are warranted to confirm these results.

The potential risk factors of postoperative cognitive dysfunction for endovascular therapy in acute ischemic stroke with general anesthesia

Background

Postoperative cognitive dysfunction (POCD) frequently occurs following endovascular therapy for acute ischemic stroke (AIS). Given the complexity of predicting AIS clinically, there is a pressing need to develop a preemptive prediction model and investigate the impact of anesthesia depth on AIS.

Methods

A total of 333 patients diagnosed with AIS were included in the study, comprising individuals with non-POCD (n = 232) or POCD (n = 101). Univariate and multivariate logistic regression analyses were utilized to examine the independent risk factors associated with POCD. A calibration, decision curve analysis, and precision-recall curves were employed to assess the model's goodness of fit.

Results

Multivariate regression analysis identified two inflammatory indicators, high-sensitivity C reactive protein (hs-CRP) and systemic immune inflammatory index (SII), and three brain injury indicators, National Institute of Health Stroke Scale (NIHSS) score, N-terminal pro-brain natriuretic peptide (NT-proBNP), and soluble protein-100 β (S100-β), which were used to construct a nomogram model.

Conclusion

The composite predictive model incorporating NIHSS score, hs-CRP, SII, NT-proBNP, and S100-β demonstrated efficacy in predicting POCD following AIS. Additionally, our results suggest a potential association between depth of anesthesia, cognitive impairment, and inflammatory response in AIS patients.

Brain health: A concern for anaesthesiologists and intensivists

Damage to the brain can have disastrous and long-lasting consequences. The European Society of Anaesthesiology and Intensive Care (ESAIC) is aware of the importance of taking good care of the brain, both of patients and of anaesthesia and intensive care unit (ICU) caregivers, and has organised a complete learning track on brain health to bring this concern to the attention of practitioners. This learning track included an online Focus Meeting on Brain Health (November 25, 2023). We here provide readers with a digest of the information that was delivered during that meeting in an opinion paper driven by the authors' own reading of the literature. It is divided according to the meeting's sessions, including how to improve the health of an injured brain, how to keep a young or old brain healthy, how to keep a healthy adult brain unimpaired, how monitoring can impact brain health in the operating room and in the intensive care unit, and how to keep the anaesthesia and ICU caregivers' brain healthy. Each part is a brief and focused summary. The main delivered messages are that the management of injured brain patients involves an adequate choice of sedation, adequate brain monitoring, and focused attention to specific points depending on the underlying pathology; that several measures can be undertaken to protect the brain of the very young needing anaesthesia; that it is possible to detect older patients at risk of postoperative neurocognitive disorders, and that dedicated perioperative management by a multidisciplinary expert team may improve their outcomes; that apparently healthy adult brains may suffer during anaesthesia; that the electroencephalogram may track peri-operative brain dysfunction, and that female patients should be given special care in this respect; that multimodal brain monitoring helps to detect pathological processes and to maintain brain homeostasis; and that burnout in anaesthesiologists can be effectively fought using personal, organisational, managerial and legal approaches.

Intraoperative use of processed electroencephalogram in a quaternary center: a quality improvement audit

Although intraoperative electroencephalography (EEG) is not consensual among anesthesiologists, growing evidence supports its use to titrate anesthetic drugs, assess the level of arousal/consciousness, and detect ischemic cerebrovascular events; in addition, intraoperative EEG monitoring may decrease the incidence of postoperative neurocognitive disorders. Based on the known and potential benefits of intraoperative EEG monitoring, an educational program dedicated to staff anesthesiologists, residents of Anesthesiology and anesthesia technicians was started at Cleveland Clinic Abu Dhabi in May 2022 and completed in June 2022, aiming to have all patients undergoing general anesthesia with adequate brain monitoring and following international initiatives promoting perioperative brain health. All the surgical cases performed under General Anesthesia at 24 daily locations were prospectively inspected during 15 consecutive working days in March 2023. The use or absence of a processed EEG monitor was registered. Of 379 surgical cases distributed by 24 locations under General Anesthesia, 233 cases (61%) had processed EEG monitoring. The specialty with the highest use of EEG monitoring was Cardiothoracic Surgery, with 100% of cases, followed by interventional Cardiology (90%) and Vascular Surgery (75%). Otorhinolaryngology (29%), Gastrointestinal Endoscopy (25%), and Interventional Pulmonology (20%) were the areas with the lowest use of EEG monitoring. Of note, in the Neuroradiology suite, no processed EEG monitor was used in cases under General Anesthesia. We identified a reasonable use of EEG monitoring during general anesthesia, unfortunately not reaching our target of 100%. The educational and support program previously implemented within the Anesthesiology Institute needs to be continued and improved, including workshops, online discussions, and journal club sessions, to increase the use of EEG monitoring in underused areas.

Depth of anesthesia monitoring: an argument for its use for patient safety

PURPOSE OF REVIEW

There have been significant advancements in depth of anesthesia (DoA) technology. The Anesthesia Patient Safety Foundation recently published recommendations to use a DoA monitor in specific patient populations receiving general anesthesia. However, the universal use of DoA monitoring is not yet accepted. This review explores the current state of DoA monitors and their potential impact on patient safety.

RECENT FINDINGS

We reviewed the current evidence for using a DoA monitor and its potential role in preventing awareness and preserving brain health by decreasing the incidence of postoperative delirium and postoperative cognitive dysfunction or decline (POCD). We also explored the evidence for use of DoA monitors in improving postoperative clinical indicators such as organ dysfunction, mortality and length of stay. We discuss the use of DoA monitoring in the pediatric population, as well as highlight the current limitations of DoA monitoring and the path forward.

SUMMARY

There is evidence that DoA monitoring may decrease the incidence of awareness, postoperative delirium, POCD and improve several postoperative outcomes. In children, DoA monitoring may decrease the incidence of awareness and emergence delirium, but long-term effects are unknown. While there are key limitations to DoA monitoring technology, we argue that DoA monitoring shows great promise in improving patient safety in most, if not all anesthetic populations.

Effect of Low-Dose Esketamine on Postoperative Delirium in Elderly Patients Undergoing Total Hip or Knee Arthroplasty: A Randomized Controlled Trial

Purpose

Postoperative delirium (POD) is a prevalent and severe complication in elderly patients undergoing major surgery, associated with increased morbidity and mortality. This randomized controlled trial aimed to investigate the effects of low-dose esketamine on the incidence of POD in elderly patients underwent total hip or knee arthroplasty.

Patients and Methods

Two hundred and sixty elderly participants were randomly assigned to either the esketamine group (Group E) (0.20mg/kg loading, 0.125mg/kg/h infusion, 0.5 mg/kg for postoperative analgesia) or the placebo group (Group P) (received normal saline). The primary outcome was the incidence of POD, with secondary outcomes including delirium subtypes, duration, intraoperative analgesic consumption, operative and anesthesia times, hemodynamic changes, postoperative pain scores, sleep quality, and common postoperative adverse events.

Results

There was no significant difference in the incidence of POD between Group E (8.5%) and Group P (10.8%). No significant differences were observed for the time of delirium onset, duration of delirium, and delirium subtype between the two groups. Patients in the esketamine group had more stable hemodynamic profile after induction and reduced the pain score of motion on the first two days postoperatively but increased the incidence of postoperative dizziness.

Conclusion

The repeated infusion of low-dose esketamine did not reduce the incidence of POD during the initial three postoperative days in elderly patients following total hip or knee arthroplasty.

Postoperative Delirium and Neurocognitive Disorders: A Comprehensive Review of Pathophysiology, Risk Factors, and Management Strategies

Postoperative delirium (POD) and neurocognitive disorders (NCDs) are common and serious complications that can occur after surgery, particularly in older adults and those with preexisting cognitive impairments. These conditions are associated with significant morbidity, increased healthcare costs, and reduced quality of life. Understanding the underlying mechanisms, risk factors, and effective management strategies for POD and NCDs is critical for improving patient outcomes and reducing the burden on healthcare systems. This comprehensive review aims to synthesize current knowledge on the pathophysiology, risk factors, and management strategies for POD and NCDs. It explores the neurobiological and molecular mechanisms contributing to these conditions, identifies the patient-related, surgical, and environmental factors that increase risk, and evaluates pharmacological and non-pharmacological approaches to prevention and treatment. A thorough literature review was conducted using recent studies, clinical guidelines, and expert consensus to provide a detailed overview of the pathophysiology, risk factors, clinical presentation, prevention, and management of POD and NCDs. The pathophysiology of POD and NCDs involves complex interactions between neuroinflammatory processes, neurotransmitter imbalances, and brain network disruptions. Risk factors include advanced age, preexisting cognitive impairment, type and duration of surgery, and perioperative complications. Management strategies emphasize a multidisciplinary approach, incorporating preoperative optimization, careful intraoperative management, and postoperative interventions. Pharmacological treatments, such as antipsychotics, and non-pharmacological approaches, including environmental modifications and cognitive rehabilitation, play crucial roles in management. Postoperative delirium and NCDs are multifactorial conditions with significant impacts on surgical outcomes. Effective management requires a comprehensive understanding of their pathophysiology and risk factors and the implementation of targeted prevention and treatment strategies. Future research should focus on personalized approaches to prevention and treatment, further elucidation of mechanisms, and developing predictive models to enhance care for patients at risk of these neurocognitive complications.

The Effect of Low-Dose Dexmedetomidine on Perioperative Neurocognitive Dysfunction in Elderly Patients Undergoing Endoscopic Retrograde Cholangiopancreatography (ERCP): A Randomized, Controlled, Double-Blind Trial

Objective

This study investigates the effect of low-dose dexmedetomidine infusion on perioperative neurocognitive function in elderly patients undergoing endoscopic retrograde cholangiopancreatography (ERCP).

Patients and Methods

This double-blind trial enrolled 80 elderly ERCP patients randomized to receive dexmedetomidine (Group D) or placebo (Group S). Group D received dexmedetomidine at 0.4 μg·kg-1·h-1 starting 15 minutes before surgery until completion, along with propofol at 1.5 mg/kg for anesthesia. Group S received saline and propofol in a similar manner. Anesthesia was maintained with dexmedetomidine at 0.4 μg·kg-1·h-1 and propofol at 1-2 mg/kg during surgery. Cognitive function was assessed using the Mini-Mental State Examination (MMSE) preoperatively and on postoperative days 1, 3, and 5. Primary outcome was perioperative neurocognitive disorder (PND) incidence on day 5; secondary outcomes included changes in perioperative IL-6, cortisol, S100-β, hemodynamics, anesthesia parameters, postoperative pain, agitation scores, and adverse events.

Results

All 80 patients completed the trial. On postoperative day 5, the cumulative probability of PND incidence was significantly lower in Group D than in Group S (12.5% vs 35%, P=0.018). Group D also had lower levels of IL-6 (F=199.472, P<0.001), S100-β (F=2681.964, P<0.001), and cortisol (F=137.637, P<0.001). Propofol doses were lower in Group D (706.1 ± 202.4 vs 1003.3 ± 203.7, P<0.001), and bradycardia rates were higher (45% vs 15%, P=0.003), though atropine use did not significantly differ between groups. Group D showed greater stability in mean arterial pressure. Postoperative complications and adverse reactions were similar across groups.

Conclusion

Perioperative low-dose dexmedetomidine infusion with propofol in elderly ERCP patients ensures safe and effective monitored anesthesia care (MAC), reducing PND incidence by mitigating peripheral inflammation and stress responses. Long-term follow-up is needed to fully evaluate PND incidence.

The influence of sleep disorders on perioperative neurocognitive disorders among the elderly: A narrative review

This review comprehensively assesses the epidemiology, interaction, and impact on patient outcomes of perioperative sleep disorders (SD) and perioperative neurocognitive disorders (PND) in the elderly. The incidence of SD and PND during the perioperative period in older adults is alarmingly high, with SD significantly contributing to the occurrence of postoperative delirium. However, the clinical evidence linking SD to PND remains insufficient, despite substantial preclinical data. Therefore, this study focuses on the underlying mechanisms between SD and PND, underscoring that potential mechanisms driving SD-induced PND include uncontrolled central nervous inflammation, blood-brain barrier disruption, circadian rhythm disturbances, glial cell dysfunction, neuronal and synaptic abnormalities, impaired central metabolic waste clearance, gut microbiome dysbiosis, hippocampal oxidative stress, and altered brain network connectivity. Additionally, the review also evaluates the effectiveness of various sleep interventions, both pharmacological and nonpharmacological, in mitigating PND. Strategies such as earplugs, eye masks, restoring circadian rhythms, physical exercise, noninvasive brain stimulation, dexmedetomidine, and melatonin receptor agonists have shown efficacy in reducing PND incidence. The impact of other sleep-improvement drugs (e.g., orexin receptor antagonists) and methods (e.g., cognitive-behavioral therapy for insomnia) on PND is still unclear. However, certain drugs used for treating SD (e.g., antidepressants and first-generation antihistamines) may potentially aggravate PND. By providing valuable insights and references, this review aimed to enhance the understanding and management of PND in older adults based on SD.

Advancing Perioperative Neurocognitive Health: A Critical Review of Predictive Tools, Diagnostic Methods, and Interventional Strategies

Perioperative neurocognitive disorders (PNDs) affect a large percentage of people who undergo surgeries that need general anesthesia. There is an increased risk of death and a major disruption to postoperative self-care as a result of this. This study compiles all the relevant materials that the authors have found to investigate postnatal depression and its causes, as well as the methods used to determine the probability and severity of PNDs and how to reduce their risk before surgery. Postnatal depression can have many causes, and this text explores some of them. These include a history of alcohol or opiate use, immunological dysregulation, advanced age, educational background, infections, neurocognitive impairment, and pre-existing chronic inflammatory disorders. It also delves into various methods used to gauge the likelihood and severity of postpartum depression. The following assessment tools were covered: the Clock Drawing Test, Domain-Specific Tests, the Mini-Mental State Examination, and the Montreal Cognitive Assessment. In addition to biochemical markers, neuroimaging techniques play an important role in diagnosis. The Frailty Fried assessment, which measures inertia, sluggishness, lack of physical activity, fatigue, and unintentional weight loss, is a key prognostic sign that is highlighted. There is strong evidence that the index, which is derived from these five characteristics, may accurately predict the likelihood of PNDs. Risk mitigation strategies are also covered in this research. Preoperative brain plasticity-based therapies, such as physical exercise and intensive cognitive training, can significantly reduce the incidence and severity of postoperative neurocognitive disorders. A peripheral nerve block, monitoring cerebral oxygen saturation, dexmedetomidine, and a reduction in anesthesia depth are all ways to improve anesthetic procedures. Methods that lower blood pressure should be avoided, the body temperature should be kept down during surgery, or the time without liquids should be lengthened; all of these raise the risk of postoperative nausea and vomiting and make it worse. Potential approaches include a Mediterranean diet, physical activity, cognitive stimulation, smoking cessation, alcohol reduction, avoidance of anticholinergic medications, and non-steroidal anti-inflammatory drug stewardship, although there is no definitive evidence for successful postoperative neurocognitive rehabilitation procedures. More standardized diagnostic criteria, evaluation methods, and PND classification are urgently needed, according to this study. Different cases of PNDs are characterized by different combinations of tests, cutoff values, and methods because there is a broad variety of diagnostic tests used to make the diagnosis. Until now, PNDs and pre-existing neurocognitive disorders have been diagnosed using the Diagnostic and Statistical Manual of Mental Disorders (DSM-V). With an aging population comes an increase in the occurrence and prevalence of PNDs, which calls for a specific way to classify and describe the condition.

Itaconate alleviates anesthesia/surgery-induced cognitive impairment by activating a Nrf2-dependent anti-neuroinflammation and neurogenesis via gut-brain axis

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a common neurological complication of anesthesia and surgery in aging individuals. Neuroinflammation has been identified as a hallmark of POCD. However, safe and effective treatments of POCD are still lacking. Itaconate is an immunoregulatory metabolite derived from the tricarboxylic acid cycle that exerts anti-inflammatory effects by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. In this study, we investigated the effects and underlying mechanism of 4-octyl itaconate (OI), a cell-permeable itaconate derivative, on POCD in aged mice.

METHODS

A POCD animal model was established by performing aseptic laparotomy in 18-month-old male C57BL/6 mice under isoflurane anesthesia while maintaining spontaneous ventilation. OI was intraperitoneally injected into the mice after surgery. Primary microglia and neurons were isolated and treated to lipopolysaccharide (LPS), isoflurane, and OI. Cognitive function, neuroinflammatory responses, as well as levels of gut microbiota and their metabolites were evaluated. To determine the mechanisms underlying the therapeutic effects of OI in POCD, ML385, an antagonist of Nrf2, was administered intraperitoneally. Cognitive function, neuroinflammatory responses, endogenous neurogenesis, neuronal apoptosis, and Nrf2/extracellular signal-related kinases (ERK) signaling pathway were evaluated.

RESULTS

Our findings revealed that OI treatment significantly alleviated anesthesia/surgery-induced cognitive impairment, concomitant with reduced levels of the neuroinflammatory cytokines IL-1β and IL-6, as well as suppressed activation of microglia and astrocytes in the hippocampus. Similarly, OI treatment inhibited the expression of IL-1β and IL-6 in LPS and isoflurane-induced primary microglia in vitro. Intraperitoneal administration of OI led to alterations in the gut microbiota and promoted the production of microbiota-derived metabolites associated with neurogenesis. We further confirmed that OI promoted endogenous neurogenesis and inhibited neuronal apoptosis in the hippocampal dentate gyrus of aged mice. Mechanistically, we observed a decrease in Nrf2 expression in hippocampal neurons both in vitro and in vivo, which was reversed by OI treatment. We found that Nrf2 was required for OI treatment to inhibit neuroinflammation in POCD. The enhanced POCD recovery and promotion of neurogenesis triggered by OI exposure were, at least partially, mediated by the activation of the Nrf2/ERK signaling pathway.

CONCLUSIONS

Our findings demonstrate that OI can attenuate anesthesia/surgery-induced cognitive impairment by stabilizing the gut microbiota and activating Nrf2 signaling to restrict neuroinflammation and promote neurogenesis. Boosting endogenous itaconate or supplementation with exogenous itaconate derivatives may represent novel strategies for the treatment of POCD.

Postoperative cognitive dysfunction in elderly patients with colorectal cancer: A randomized controlled study comparing goal-directed and conventional fluid therapy

To investigate the impact of goal-directed fluid therapy (GDFT) on postoperative cognitive dysfunction (POCD) in elderly patients with colorectal cancer, we conducted a randomized controlled trial. Eighty elderly patients who underwent elective laparoscopic radical resection of colorectal cancer were randomly assigned to either the GDFT group or the conventional fluid therapy group. The primary outcome was the incidence of POCD during the initial 7 postoperative days, while secondary outcomes included inflammatory marker levels such as interleukin-6 (IL-6) and S100β protein, hemodynamics, level of lactic acid, postoperative functional recovery, and complications. Among 88 randomized patients, 80 were evaluable for the primary outcome. The incidence of POCD was significantly lower in the GDFT group (15.0%) compared to the conventional fluid therapy group (30.0%), with the highest occurrence observed on day 3 postoperatively in both groups (P < 0.05). IL-6 and S100β concentrations were consistently lower in the GDFT group than in the conventional fluid therapy group at the corresponding time points (P < 0.05). The GDFT group exhibited more stable perioperative hemodynamics and lower lactate levels (P < 0.05). Moreover, patients in the GDFT group exhibited better postoperative functional recovery indicators and a lower incidence of postoperative complications (P < 0.05). In summary, GDFT appears to reduce the incidence of early POCD, accelerate postoperative recovery, and enhance overall prognosis.

Post-Anesthesia Cognitive Dysfunction in Mice Is Associated with an Age-Related Increase in Neuronal Intracellular [Ca2+]-Neuroprotective Effect of Reducing Intracellular [Ca2+]: In Vivo and In Vitro Studies

Background: Postoperative cognitive dysfunction (POCD) is a common disorder after general anesthesia in elderly patients, the precise mechanisms of which remain unclear. Methods: We investigated the effect of isoflurane with or without dantrolene pretreatment on intracellular calcium concentration ([Ca2+]i), reactive oxygen species (ROS) production, cellular lactate dehydrogenase (LDH) leak, calpain activity, and cognitive function using the Morris water maze test of young (3 months), middle-aged (12-13 months), and aged (24-25 months) C57BL6/J mice. Results: Aged cortical and hippocampal neurons showed chronically elevated [Ca2+]i compared to young neurons. Furthermore, aged hippocampal neurons exhibited higher ROS production, increased LDH leak, and elevated calpain activity. Exposure to isoflurane exacerbated these markers in aged neurons, contributing to increased cognitive deficits in aged mice. Dantrolene pretreatment reduced [Ca2+]i for all age groups and prevented or significantly mitigated the effects of isoflurane on [Ca2+]i, ROS production, LDH leak, and calpain activity in aged neurons. Dantrolene also normalized or improved age-associated cognitive deficits and mitigated the cognitive deficits caused by isoflurane. Conclusions: These findings suggest that isoflurane-induced cytotoxicity and cognitive decline in aging are linked to disruptions in neuronal intracellular processes, highlighting the reduction of [Ca2+]i as a potential therapeutic intervention.