Perioperative Vascular Biomarker Profiling in Elective Surgery Patients Developing Postoperative Delirium: A Prospective Cohort Study

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.

Accumulating the key proteomic signatures associated with delirium: Evidence from systematic review

Delirium is a severe neuropsychiatric illness that occurs frequently in intensive care and postoperative units which results in prolonged hospital stays and increases patient's mortality and morbidity rates. This review focused on accumulating the common key proteomic signatures significantly associated with delirium. We carried out a systematic literature review of studies on delirium proteomic biomarkers published between 1st January 2000 and 31st December 2023 from the following electronic bibliographic databases including PubMed, Scopus, and EBSCOhost (CINAHL, Medline). A total of 1746 studies were identified and reviewed, and 78 studies were included in our review. The PRISMA guidelines, the PEO framework, and JBI quality assessment method were followed in this review to maintain the inclusion and exclusion criteria and risk of bias assessment. Most of the included studies were of the cohort (68%) and case-control (23%) design. We have accumulated a total of 313 proteins or gene encoded proteins of which 189 were unique. Among the unique proteins, we focused on the top 13 most investigated proteins (IL-6, CRP, IL-8, S100B, IL-10, TNF-a, IL-1b, Cortisol, MCP-1, GFAP, IGF-1, IL-1ra, and NFL) that are significantly associated with delirium. Most of these are cytokines and inflammatory proteins indicating a strong interconnection with delirium. There was remarkable inconsistency among the studies in reporting the specific potential proteomic biomarker. No single proteomic biomarker can be solely used to diagnose and predict delirium. The current review provides a rationale for further molecular investigation of delirium-related proteomic biomarkers. Also, it's recommended to conduct further in-depth molecular research to decipher drug target biomolecules for potential prognostic, diagnostic, and therapeutic development against delirium.

Intraoperative Use of Sodium Bicarbonate Ringer's Solution Instead of Sodium Lactate Ringer's Solution to Reduce Endothelial Glycocalyx Degradation and Improve Postoperative Recovery During Cardiopulmonary Bypass Cardiac Surgery: A Single-Center Prospective Cohort Study

Objective

To investigate the effect of sodium bicarbonate Ringer's solution (BRS) on the degradation of endothelial glycocalyx components in patients undergoing cardiopulmonary bypass (CPB) during cardiac surgery, and to evaluate its impact on endothelial glycocalyx preservation and postoperative recovery.

Patients and Methods

A total of eight patients scheduled for elective CPB heart surgery were included and randomly divided into two groups: the sodium lactate Ringer's solution (LRS) group and the BRS group. ELISA was used to measure plasma concentrations of syndecan-1, matrix metalloproteinase-9 (MMP-9), matrix metalloproteinase-3 (MMP-3), IL-6, IL-8, TNF-α, and TGF-β at predefined time points: T0 (before induction of anesthesia), T3 (immediately after weaning from CPB), T5 and T6 (24 and 72 hours postoperatively). Serum creatinine concentrations were measured within 48 hours postoperatively. The incidence of postoperative delirium (POD) was assessed three days after surgery. Postoperative mechanical ventilation time, duration of stay in the intensive care unit and hospital stay were also documented.

Results

The BRS group had significantly lower plasma concentrations of syndecan-1 at T3 (7.98 [7.43, 8.92] ng/mL vs 9.54 [8.4, 10.73] ng/mL, P < 0.001) and T5 (4.20 [3.31, 4.96] ng/mL vs 5.40 [3.95, 6.55] ng/mL, P = 0.001) in comparison with the LRS group (P<0.01). Syndecan-1 levels in both groups were similar at T6 (3.18 [2.88, 3.5]ng/mL vs 3.12 [2.77, 3.45] ng/mL, P > 0.05). Additionally, MMP-9, MMP-3, IL-6 and IL-8 were significantly lower at T3 and T5 in the BRS group (P<0.05 and P<0.01, respectively). However, no significant differences were observed between the two groups in the incidence of acute kidney injury (AKI) or POD (P > 0.05).

Conclusion

BRS has the potential to reduce glycocalyx degradation in patients undergoing heart valve surgery with CPB. However, both groups demonstrated similar post-postoperative clinical outcomes, including the rates of AKI and POD.

The association of pre-operative biomarkers of endothelial dysfunction with the risk of post-operative neurocognitive disorders: results from the BioCog study

INTRODUCTION

Endothelial dysfunction (ED) promotes the development of atherosclerosis, and studies suggest an association with age-related neurocognitive disorders. It is currently unclear whether ED is also associated with the risk of perioperative neurocognitive disorders.

METHOD

We included 788 participants aged ≥ 65 years of the BioCog study. Patients were scheduled to undergo elective surgery with expected duration > 60 min. Blood was collected before surgery for measurement of 5 biomarkers of ED: asymmetric and symmetric dimethylarginine (ADMA; SDMA), intercellular and vascular adhesion molecule (ICAM-1, VCAM-1), and von Willebrand factor (vWF). Patients were monitored for the occurrence of postoperative delirium (POD) daily until the 7th postoperative day. 537 (68.1%) patients returned for a 3-month follow-up. Post-operative cognitive dysfunction (POCD) was defined from the change in results on a battery of 6 neuropsychological tests between baseline and 3 months, compared to the change in results of a control group during the 3-month interval. The associations of each of the 5 ED biomarkers with POD and POCD respectively were determined using multiple logistic regression analyses with adjustment for age, sex, surgery type, pre-morbid IQ, body mass index, hypertension, diabetes, HbA1C, triglyceride, total and HDL cholesterol.

RESULTS

19.8% of 788 patients developed POD; 10.1% of 537 patients had POCD at 3 months. Concentrations of ED biomarkers were not significantly associated with a POD. A higher VCAM-1 concentration was associated with a reduced POCD risk (adjusted odds ratio 0.55; 95% CI: 0.35-0.86). No further statistically significant results were found.

CONCLUSION

Pre-operative concentrations of ED biomarkers were not associated with POD risk. We unexpectedly found higher VCAM-1 to be associated with a reduced POCD risk. Further studies are needed to evaluate these findings.

Sleep and circadian biomarkers of postoperative delirium (SLEEP-POD): protocol for a prospective and observational cohort study

INTRODUCTION

Surgical patients over 70 experience postoperative delirium (POD) complications in up to 50% of procedures. Sleep/circadian disruption has emerged as a potential risk factor for POD in epidemiological studies. This protocol presents a single-site, prospective observational study designed to examine the relationship between sleep/circadian regulation and POD and how this association could be moderated or mediated by Alzheimer's disease (AD) pathology and genetic risk for AD.

METHODS AND ANALYSIS

Study staff members will screen for eligible patients (age ≥70) seeking joint replacement or spinal surgery at Massachusetts General Hospital (MGH). At the inclusion visit, patients will be asked a series of questionnaires related to sleep and cognition, conduct a four-lead ECG recording and be fitted for an actigraphy watch to wear for 7 days before surgery. Blood samples will be collected preoperatively and postoperatively and will be used to gather information about AD variant genes (APOE-ε4) and AD-related pathology (total and phosphorylated tau). Confusion Assessment Method-Scale and Montreal Cognitive Assessment will be completed twice daily for 3 days after surgery. Seven-day actigraphy assessments and Patient-Reported Outcomes Measurement Information System questionnaires will be performed 1, 3 and 12 months after surgery. Relevant patient clinical data will be monitored and recorded throughout the study.

ETHICS AND DISSEMINATION

This study is approved by the IRB at MGH, Boston, and it is registered with the US National Institutes of Health on ClinicalTrials.gov (NCT06052397). Plans for dissemination include conference presentations at a variety of scientific institutions. Results from this study are intended to be published in peer-reviewed journals. Relevant updates will be made available on ClinicalTrials.gov.

TRIAL REGISTRATION NUMBER

NCT06052397.

[Postoperative Delirium in Patients on Cardiopulmonary Bypass for Cardiovascular Surgeries: Incidence and Influencing Factors]

Objective

To investigate the incidence and influencing factors of postoperative delirium (POD) and subsyndromal delirium (SSD) in patients connected to cardiopulmonary bypass during cardiovascular surgeries.

Methods

We collected the general data and the data for the perioperative hematological, physiological, and biochemical indicators and the surgical and therapeutic conditions of patients connected to cardiopulmonary bypass during the course of cardiovascular surgeries conducted at a tertiary-care hospital in Hubei province between May 2022 and September 2022. The outcome indicators, including the incidence of POD and SSD, were assessed with the Nursing Delirium Screening Scale (Nu-DESC). Multinomial logistic regression was performed to analyze the influencing factors of patients with different statuses of POD and SSD.

Results

Among the 202 patients, the incidence of SSD, SSD progressing to POD, and no POD or SSD (ND) progressing to POD were 13.4%, 6.4%, and 34.2%, respectively. Regression analysis showed that, with ND patients as the controls, the influencing factors for SSD were preoperative blood glucose (odds ratio [ OR]=0.38, 95% confidence interval [ CI]: 0.19-0.76), intraoperative platelet transfusion ( OR=0.37, 95% CI: 0.15-0.92), intraoperative etomidate ( OR=0.93, 95% CI: 0.87-0.98), and postoperative total bilirubin level ( OR=1.04, 95% CI: 1.01-1.07). For the progression of SSD to POD, the influencing factors were age ( OR=1.09, 95% CI: 1.01-1.17), ASA classification of IV and above ( OR=10.72, 95% CI: 1.85-62.08), intraoperative dexmedetomidine ( OR=1.01, 95% CI: 1.003-1.02), and the duration of mechanical ventilation ( OR=1.04, 95% CI: 1.01-1.07). For the progression of ND to POD, the influencing factors were age ( OR=1.06, 95% CI: 1.02-1.10), middle or high school education ( OR=0.35, 95% CI: 0.15-0.83), and the duration of mechanical ventilation ( OR=1.04, 95% CI: 1.01-1.07).

Conclusion

Age, education, ASA classification, preoperative blood glucose, intraoperative platelet transfusion, intraoperative etomidate, intraoperative dexmedetomidine, postoperative total bilirubin, and the duration of mechanical ventilation are influencing factors for different statuses of POD and SSD among patients connected to cardiopulmonary bypass when they are undergoing cardiovascular surgeries. The influencing factors vary across groups of patients with different statuses of POD and SSD. Therefore, we should accurately assess the risk factors of patients with different statuses of POD and SSD and carry out corresponding interventions, thereby preventing or reducing the occurrence of POD and SSD, and ultimately promoting enhanced recovery after surgery.

Intraoperative plasma proteomic changes in cardiac surgery: In search of biomarkers of post-operative delirium

PURPOSE

Delirium presents a significant healthcare burden. It complicates post-operative care in up to 50% of cardiac surgical patients with worse outcomes, longer hospital stays and higher cost of care. Moreover, the nature of delirium following cardiac surgery with cardiopulmonary bypass (CPB) remains unclear, the underlying pathobiology is poorly understood, status quo diagnostic methods are subjective, and diagnostic biomarkers are currently lacking.

OBJECTIVE

To identify diagnostic biomarkers of delirium and for insights into possible neuronal pathomechanisms.

EXPERIMENTAL DESIGN

Comparative proteomic analyses were performed on plasma samples from a nested matched cohort of patients who underwent cardiac surgery. Validation by targeted proteomics was performed in an independent set of samples. Biomarkers were assessed for biological functions and diagnostic accuracy.

RESULTS

Forty-seven percent of subjects demonstrated delirium. Of 3803 proteins identified from patient samples by multiplexed quantitative proteomics, 16 were identified as signatures of exposure to CPB, and 11 biomarkers distinguished delirium cases from non-cases (AuROC = 93%). Notable among these biomarkers are C-reactive protein, serum amyloid A-1 and cathepsin-B.

CONCLUSIONS AND CLINICAL RELEVANCE

The interplay of systemic and central inflammatory markers sheds new light on delirium pathogenesis. This work suggests that accurate identification of cases may be achievable using panels of biomarkers.

Preclinical and translational models for delirium: Recommendations for future research from the NIDUS delirium network

Delirium is a common, morbid, and costly syndrome that is closely linked to Alzheimer's disease (AD) and AD-related dementias (ADRD) as a risk factor and outcome. Human studies of delirium have advanced our knowledge of delirium incidence and prevalence, risk factors, biomarkers, outcomes, prevention, and management. However, understanding of delirium neurobiology remains limited. Preclinical and translational models for delirium, while challenging to develop, could advance our knowledge of delirium neurobiology and inform the development of new prevention and treatment approaches. We discuss the use of preclinical and translational animal models in delirium, focusing on (1) a review of current animal models, (2) challenges and strategies for replicating elements of human delirium in animals, and (3) the utility of biofluid, neurophysiology, and neuroimaging translational markers in animals. We conclude with recommendations for the development and validation of preclinical and translational models for delirium, with the goal of advancing awareness in this important field.

Identification of risk factors for delirium, cognitive decline, and dementia after cardiac surgery (FINDERI-find delirium risk factors): a study protocol of a prospective observational study

Background

Postoperative delirium is a common complication of cardiac surgery associated with higher morbidity, longer hospital stay, risk of cognitive decline, dementia, and mortality. Geriatric patients, patients undergoing cardiac surgery, and intensive care patients are at a high risk of developing postoperative delirium. Gold standard assessments or biomarkers to predict risk factors for delirium, cognitive decline, and dementia in patients undergoing cardiac surgery are not yet available.

Methods

The FINDERI trial (FINd DElirium RIsk factors) is a prospective, single-center, observational study. In total, 500 patients aged ≥ 50 years undergoing cardiac surgery at the Department of Cardiovascular and Thoracic Surgery of the University of Göttingen Medical Center will be recruited. Our primary aim is to validate a delirium risk assessment in context of cardiac surgery. Our secondary aims are to identify specific preoperative and perioperative factors associated with delirium, cognitive decline, and accelerated dementia after cardiac surgery, and to identify blood-based biomarkers that predict the incidence of postoperative delirium, cognitive decline, or dementia in patients undergoing cardiac surgery.

Discussion

This prospective, observational study might help to identify patients at high risk for delirium prior to cardiac surgery, and to identify important biological mechanisms by which cardiac surgery is associated with delirium. The predictive value of a delirium screening questionnaire in cardiac surgery might be revealed. Finally, the identification of specific blood biomarkers might help to predict delirium, cognitive decline, and dementia in patients undergoing cardiac surgery.

Trial registration: Ethics approval for this study was obtained from the IRB of the University of Göttingen Medical Center. The investigators registered this study in the German Clinical Trials Register (DRKS; https://www.drks.de) (DRKS00025095) on April 19th, 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02732-4.

Elevated neuron-specific enolase level is associated with postoperative delirium and detection of phosphorylated neurofilament heavy subunit: A prospective observational study

BACKGROUND

Delirium is the most common central nervous system complication after surgery. Detection of phosphorylated neurofilament heavy subunit in the serum reflects axonal damage within the central cervous system and is associated with the severity of postoperative delirium. Neuron-specific enolase and S100 calcium-binding protein β have been identified as possible serum biomarkers of postoperative delirium. This study examined the association of the levels of these markers with incidence of postoperative delirium and detection of phosphorylated neurofilament heavy subunit.

METHODS

This study represents a post hoc analysis of 117 patients who participated in a prospective observational study of postoperative delirium in patients undergoing cancer surgery. Patients were clinically assessed for development of postoperative delirium within the first five days of surgery. Serum levels of phosphorylated neurofilament heavy subunit, neuron-specific enolase, and S100 calcium-binding protein β levels were measured on postoperative day 3.

RESULTS

Forty-one patients (35%) were clinically diagnosed with postoperative delirium. Neuron-specific enolase level (P < 0.0001) and the proportion of patients positive for phosphorylated neurofilament heavy subunit (P < 0.0001) were significantly higher in the group of patients with postoperative delirium. Neuron-specific enolase level discriminated between patients with and without clinically diagnosed postoperative delirium with significantly high accuracy (area under the curve [AUC], 0.87; 95% confidence interval [CI], 0.79-0.95; P < 0.0001). Neuron-specific enolase level was associated with incidence of postoperative delirium independently of age (adjusted odds ratio, 8.291; 95% Cl, 3.506-33.286; P < 0.0001). The AUC for the serum neuron-specific enolase level in detecting phosphorylated neurofilament heavy subunit was significant (AUC, 0.78; 95% CI, 0.66-0.90; P < 0.0001).

CONCLUSION

Elevated serum neuron-specific enolase was associated with postoperative delirium independent of age as well as detection of phosphorylated neurofilament heavy subunit in serum. Serum neuron-specific enolase and phosphorylated neurofilament heavy subunit might be useful as biomarkers of postoperative delirium.

TRIAL REGISTRATION

University Medical Information Network (UMIN) trial ID: UMIN000010329; https://clinicaltrials.gov/.

Neural autoantibodies in delirium

BACKGROUND

Delirium in hospitalized and intensive care unit patients is an emerging condition due to its rapid-onset requiring fast action to mitigate a worse clinical outcome. Although several causes and conditions are known, the association between delirium and neural autoantibodies has often been neglected in cohort studies and reviews as causing delirium. The aim of our review is to delineate the occurrence and type of neural autoantibodies and to depict other biological markers of autoimmunity in relationship to delirium.

METHODS

For this narrative review Pubmed research was done to select articles about delirium and neural autoantibodies.

RESULTS

We can report on several cell-surface autoantibodies such as anti-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors, anti-contactin associated protein 2, anti-Leucin rich glioma inactivated protein 1, anti-dipeptidyl-peptidase-like 6 protein, anti-glycine receptor and anti-myelin autoantibodies, as well as intracellular autoantibodies such as anti-glutamic acid decarboxylase 65 (GAD65), anti-CV2 and anti-Hu associated with delirium in patients. Our case reports and case series screening revealed that 20 of 63 patients with delirium presented neural autoantibodies, thus revealing a 32% frequency of autoantibody-associated delirium in delirium patients. Our main finding is that delirium's hyperactive form is associated with neural autoantibodies. Diagnosing delirium differentially is difficult, as in patients with delirium and GAD65 autoantibodies, as it must be distinguished from other psychopathological excitation states such as mania. We also describe autoimmune delirium's potential pathophysiologic pathways.

CONCLUSIONS

The existence of neural autoantibodies in delirious patients is scientifically and clinically highly relevant in its diagnosis, therapy, and pathogenesis. More large-scale studies should be conducted to evaluate their significance and prevalence in delirium.