C-reactive Protein Predicts Postoperative Delirium Following Vascular Surgery

The Pathophysiology and Biomarkers of Delirium

Delirium is a major disturbance in the mental state characterized by fluctuations in arousal, deficits in attention, distorted perception, and disruptions in memory and cognitive processing. Delirium affects approximately 18% to 25% of hospital inpatients, with even higher rates observed during critical illness. To develop therapies to shorten the duration and limit the adverse effects of delirium, it is important to understand the mechanisms underlying its presentation. Neuroimaging modalities such as magnetic resonance imaging (MRI), positron emission tomography, functional MRI, and near-infrared spectroscopy point to global atrophy, white matter changes, and disruptions in cerebral blood flow, oxygenation, metabolism, and connectivity as key correlates of delirium pathogenesis. Electroencephalography demonstrates generalized slowing of normal background activity, with pathologic decreases in variability of oscillatory patterns and disruptions in functional connectivity among specific brain regions. Elevated serum biomarkers of inflammation, including interleukin-6, C-reactive protein, and S100B, suggest a role of dysregulated inflammatory processes and cellular metabolism, particularly in perioperative and sepsis-related delirium. Emerging animal models that can mimic delirium-like clinical states will reveal further insights into delirium pathophysiology. The combination of clinical and basic science methods of exploring delirium shows great promise in elucidating its underlying mechanisms and revealing potential therapeutic targets.

Incidence and relative risk of delirium after major surgery for patients with pre-operative depression: a systematic review and meta-analysis

BACKGROUND

Delirium is a common and potentially serious complication after major surgery. A previous history of depression is a known risk factor for experiencing delirium in patients admitted to the hospital, but the generalised risk has not been estimated in surgical patients.

METHODS

We conducted a systematic review and meta-analysis of studies reporting the incidence or relative risk (or relative odds) of delirium in the immediate postoperative period for adults with pre-operative depression. We included studies that defined depression as either a formal pre-existing diagnosis or having clinically important depressive symptoms measured using a patient-reported instrument before surgery. Multilevel random effects meta-analyses were used to estimate the pooled incidences and pooled relative risks. We also conducted subgroup analyses by various study-level characteristics to identify important moderators of pooled estimates.

RESULTS

Forty-two studies (n = 4,664,051) from five continents were included. The pooled incidence of postoperative delirium for patients with pre-operative depression was 29% (95%CI 17-43%, I2 = 99.0%), compared with 15% (95%CI 6-28%, I2 = 99.8%) in patients without pre-operative depression and 21% (95% CI 11-33%, I2 = 99.8%) in the cohorts overall. For patients with pre-operative depression, the risk of delirium was 1.91 times greater (95%CI 1.68-2.17, I2 = 42.0%) compared with patients without pre-operative depression.

CONCLUSIONS

Patients with a previous diagnosis of depression or clinically important depressive symptoms before surgery have substantially greater risk of experiencing delirium after surgery. Clinicians and patients should be informed of these increased risks. Robust screening and other risk mitigation strategies for postoperative delirium are warranted, especially for patients with pre-operative depression.

The interrelationship between multiple long-term conditions (MLTC) and delirium: a scoping review

INTRODUCTION

Delirium and multiple long-term conditions (MLTC) share numerous risk factors and have been shown individually to be associated with adverse outcomes following hospitalisation. However, the extent to which these common ageing syndromes have been studied together is unknown. This scoping review aims to summarise our knowledge to date on the interrelationship between MLTC and delirium.

METHODS

Searches including terms for delirium and MLTC in adult human participants were performed in PubMed, EMBASE, Medline, Psycinfo and CINAHL. Descriptive analysis was used to summarise findings, structured according to Synthesis Without Meta-analysis reporting guidelines.

RESULTS

After removing duplicates, 5256 abstracts were screened for eligibility, with 313 full-texts sought along with 17 additional full-texts from references in review articles. In total, 140 met inclusion criteria and were included in the final review. Much of the literature explored MLTC as a risk factor for delirium (n = 125). Fewer studies explored the impact of MLTC on delirium presentation (n = 5), duration (n = 3) or outcomes (n = 6) and no studies explored how MLTC impacts the treatment of delirium or whether having delirium increases risk of developing MLTC. The most frequently used measures of MLTC and delirium were the Charlson Comorbidity Index (n = 98/140) and Confusion Assessment Method (n = 81/140), respectively.

CONCLUSION

Existing literature largely evaluates MLTC as a risk factor for delirium. Major knowledge gaps identified include the impact of MLTC on delirium treatment and the effect of delirium on MLTC trajectories. Current research in this field is limited by significant heterogeneity in defining both MLTC and delirium.

Intraoperative Dexmedetomidine for Prevention of Postoperative Cognitive Dysfunction and Delirium in Elderly Patients with Lobectomy: A Propensity Score-Matched, Retrospective Study

Purpose

This study aims to investigate whether dexmedetomidine could prevent postoperative cognitive dysfunction and delirium in patients with lobectomy.

Patients and Methods

Patients with lung cancer who underwent thoracoscopic lobectomy under general anesthesia were enrolled in this study and divided into dexmedetomidine group or control group. Propensity-score match (PSM) was used to reduce the bias and imbalance of confounding variables. After PSM, 87 patients in each group were included. Primary outcomes were postoperative cognitive function and delirium. Secondary outcomes include plasma TNF-α, IL-6, and S100 β protein concentrations. Adverse events were also collected.

Results

There were no significant differences in the demographic characteristics and hemodynamic parameters between the two groups. Compared with the control group, the MoCA scores were significantly higher (P<0.01), while the incidence of delirium (P<0.01) and the plasma TNF-α (P<0.01), IL-6 (P<0.01), and S100 β protein (P<0.01) concentrations were significantly lower in the dexmedetomidine group at 7 days post-operatively. The incidences of adverse events were similar between the two groups.

Conclusion

Dexmedetomidine could prevent postoperative cognitive dysfunction and delirium in patients with lobectomy by decreasing neuroinflammation.

Risk factors and associated outcomes of postoperative delirium after open abdominal aortic aneurysm repair

OBJECTIVE

Open abdominal aortic aneurysm repair (OAR) is a major vascular procedure that incurs a large physiologic demand, increasing the risk for complications such as postoperative delirium (POD). We sought to characterize POD incidence, identify delirium risk factors, and evaluate the effect of delirium on postoperative outcomes. We hypothesized that POD following OAR would be associated with increased postoperative complications and resource utilization.

METHODS

This was a retrospective study of all OAR cases from 2012 to 2020 at a single tertiary care center. POD was identified via a validated chart review method based on key words and Confusion Assessment Method assessments. The primary outcome was POD, and secondary outcomes included length of stay, non-home discharge, 90-day mortality, and 1-year survival. Bivariate analysis as appropriate to the data was used to assess the association of delirium with postoperative outcomes. Multivariable binary logistic regression was used to identify risk factors for POD and Cox regression for variables associated with worse 1-year survival.

RESULTS

Overall, 198 OAR cases were included, and POD developed in 34% (n = 67). Factors associated with POD included older age (74 vs 69 years; P < .01), frailty (50% vs 28%; P < .01), preoperative dementia (100% vs 32%; P < .01), symptomatic presentation (47% vs 27%; P < .01), preoperative coronary artery disease (44% vs 28%; P = .02), end-stage renal disease (89% vs 32%; P < .01) and Charlson Comorbidity Index score >4 (42% vs 26%; P = .01). POD was associated with 90-day mortality (19% vs 5%; P < .01), non-home discharge (61% vs 30%; P < .01), longer median hospital length of stay (14 vs 8 days; P < .01), longer median intensive care unit length of stay (6 vs 3 days; P < .01), postoperative myocardial infarction (7% vs 2%; P = .045), and postoperative pneumonia (19% vs 8%; P = .01). On multivariable analysis, risk factors for POD included older age, history of end-stage renal disease, lack of epidural, frailty, and symptomatic presentation. A Cox proportional hazards model revealed that POD was associated with worse survival at 1 year (hazard ratio, 3.8; 95% confidence interval, 1.6-9.0; P = .003).

CONCLUSIONS

POD is associated with worse postoperative outcomes and increased resource utilization. Future studies should examine the role of improved screening, implementation of delirium prevention bundles, and multidisciplinary care for the most vulnerable patients undergoing OAR.

Postoperative neurocognitive disorders: A clinical guide

For years, postoperative cognitive outcomes have steadily garnered attention, and in the past decade, they have remained at the forefront. This prominence is primarily due to empirical research emphasizing their potential to compromise patient autonomy, reduce quality of life, and extend hospital stays, and increase morbidity and mortality rates, especially impacting elderly patients. The underlying pathophysiological process might be attributed to surgical and anaesthesiological-induced stress, leading to subsequent neuroinflammation, neurotoxicity, burst suppression and the development of hypercoagulopathy. The beneficial impact of multi-faceted strategies designed to mitigate the surgical and perioperative stress response has been suggested. While certain potential risk factors are difficult to modify (e.g., invasiveness of surgery), others - including a more personalized depth of anaesthesia (EEG-guided), suitable analgesia, and haemodynamic stability - fall under the purview of anaesthesiologists. The ESAIC Safe Brain Initiative research group recommends implementing a bundle of non-invasive preventive measures as a standard for achieving more patient-centred care. Implementing multi-faceted preoperative, intraoperative, and postoperative preventive initiatives has demonstrated the potential to decrease the incidence and duration of postoperative delirium. This further validates the importance of a holistic, team-based approach in enhancing patients' clinical and functional outcomes. This review aims to present evidence-based recommendations for preventing, diagnosing, and treating postoperative neurocognitive disorders with the Safe Brain Initiative approach.

Application of Multiple Omics to Understand Postoperative Delirium Pathophysiology in Humans

Delirium, an acute change in cognition, is common, morbid, and costly, particularly among hospitalized older adults. Despite growing knowledge of its epidemiology, far less is known about delirium pathophysiology. Initial work understanding delirium pathogenesis has focused on assaying single or a limited subset of molecules or genetic loci. Recent technological advances at the forefront of biomarker and drug target discovery have facilitated application of multiple "omics" approaches aimed to provide a more complete understanding of complex disease processes such as delirium. At its basic level, "omics" involves comparison of genes (genomics, epigenomics), transcripts (transcriptomics), proteins (proteomics), metabolites (metabolomics), or lipids (lipidomics) in biological fluids or tissues obtained from patients who have a certain condition (i.e., delirium) and those who do not. Multi-omics analyses of these various types of molecules combined with machine learning and systems biology enable the discovery of biomarkers, biological pathways, and predictors of delirium, thus elucidating its pathophysiology. This review provides an overview of the most recent omics techniques, their current impact on identifying delirium biomarkers, and future potential in enhancing our understanding of delirium pathogenesis. We summarize challenges in identification of specific biomarkers of delirium and, more importantly, in discovering the mechanisms underlying delirium pathophysiology. Based on mounting evidence, we highlight a heightened inflammatory response as one common pathway in delirium risk and progression, and we suggest other promising biological mechanisms that have recently emerged. Advanced multiple omics approaches coupled with bioinformatics methodologies have great promise to yield important discoveries that will advance delirium research.

Towards experimental models of delirium utilizing zebrafish

Delirium is an acute neuropsychiatric condition characterized by impaired behavior and cognition. Although the syndrome has been known for millennia, its CNS mechanisms and risk factors remain poorly understood. Experimental animal models, especially rodent-based, are commonly used to probe various pathogenetic aspects of delirium. Complementing rodents, the zebrafish (Danio rerio) emerges as a promising novel model organism to study delirium. Zebrafish demonstrate high genetic and physiological homology to mammals, easy maintenance, robust behaviors in various sensitive behavioral tests, and the potential to screen for pharmacological agents relevant to delirium. Here, we critically discuss recent developments in the field, and emphasize the developing utility of zebrafish models for translational studies of delirium and deliriant drugs. Overall, the zebrafish represents a valuable and promising aquatic model species whose use may help understand delirium etiology, as well as develop novel therapies for this severely debilitating disorder.

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.

Postoperative C-Reactive Protein Predicts Postoperative Delirium in Colorectal Cancer Following Surgery

Background

Postoperative delirium (POD) is a common complication in operative patients. Neuroinflammation has been reported to be a potential mechanism associated with the development of POD. Identifying available inflammatory markers such as C-reactive protein (CRP) would aid clinicians in early detection of POD. Previous studies have demonstrated that CRP may be a promising predictive marker for POD. Thus, this study aimed to explore the association between CRP and POD among those elderly colorectal cancer (CRC) patients.

Methods

643 patients with CRC were included in this study. CRP levels were measured before operation and on postoperative day 1. The univariate and multivariate regression analyses were used to identify risk factors for POD.

Results

Of 643 patients with CRC, 112 cases (17.4%) had POD. CRC patients with POD showed older age, higher CRP level on postoperative day 1, and higher percentage of smoking, diabetes mellitus, and chronic obstructive pulmonary disease (COPD) than CRC patients without POD. Preoperative CRP level was not associated with the POD. Univariate and multivariate regression analyses showed that older age (> 70 years), diabetes mellitus, COPD, and higher CRP level on postoperative day 1 (> 48 mg/L) were risk factors for POD in CRC patients.

Conclusion

Postoperative CRP level is an independent indicator for POD among CRC patients, suggesting the predictive role of postoperative CRP levels for POD in elderly CRC patients undergoing surgery.

Proteomics for the Discovery of Clinical Delirium Biomarkers: A Systematic Review of Major Studies

Delirium represents a significant health care burden, diagnosed in more than 2 million elderly Americans each year. In the surgical population, delirium remains the most common complication among elderly patients, and is associated with longer hospital stays, higher costs of care, increased mortality, and functional impairment. The pathomechanism of disease is poorly understood, with current diagnostic approaches somewhat subjective and arbitrary, and definitive diagnostic biomarkers are currently lacking. Despite the recent interest in delirium research, biomarker discovery for it remains new. Most attempts to discover biomarkers are targeted studies that seek to assess the involvement of one or more members of a focused panel of candidates in delirium. For a more unbiased, system-biology view, we searched literature from Medical Literature Analysis and Retrieval System Online (MEDLINE), Cochrane Central, Web of Science, SCOPUS, and Dimensions between 2016 and 2021 for untargeted proteomic discovery studies for biomarkers of delirium conducted on human geriatric subjects. Two reviewers conducted an independent review of all search results and resolved discordance by consensus. From an overall search of 1172 publications, 8 peer-reviewed studies met our defined inclusion criteria. The 370 unique perioperative biomarkers identified in these reports are enriched in pathways involving activation of the immune system, inflammatory response, and the coagulation cascade. The most frequently identified biomarker was interleukin-6 (IL-6). By reviewing the distribution of protein biomarker candidates from these studies, we conclude that a panel of proteins, rather than a single biomarker, would allow for discriminating delirium cases from noncases. The paucity of hypothesis-generating studies in the peer-reviewed literature also suggests that a system-biology view of delirium pathomechanisms has yet to fully emerge.

Association of C-reactive protein to albumin ratio with postoperative delirium and mortality in elderly patients undergoing hip fracture surgery: A retrospective cohort study in a single large center

BACKGROUND

Postoperative delirium is a common complication in elderly patients who have undergone hip fracture surgery. Since postoperative delirium is associated with poor outcomes and the treatment is very complicated, identifying the patients at high risk for delirium and providing more attentive care to prevent postoperative delirium is essential. In this study, we aimed to assess the association of an elevated C-reactive protein (CRP)/albumin ratio with the increased incidence of postoperative delirium in elderly people who had undergone hip fracture surgery.

METHODS

A total of 629 patients who underwent hip fracture surgery between January 2014 and December 2018 were retrospectively analyzed. Patients were classified into two groups according to preoperative CRP/albumin cut-off levels (<1.5 and ≥1.5). We performed a propensity score matching analysis to compare the incidence of postoperative delirium and overall mortality between the two groups. Multivariate logistic regression and Cox regression analyses were performed to examine the association of the preoperative CRP/albumin ratio with postoperative delirium and overall mortality.

RESULTS

There were significant differences in the incidence of postoperative delirium (18.0 % vs. 35.8 %, P < 0.001) and overall mortality (26.7 % vs. 46.9 %, P < 0.001) between the groups before matching. We also observed significant differences in the incidence of postoperative delirium (20.7 % vs. 32.7 %, P = 0.019) and overall mortality (34.7 % vs. 46.0 %, P = 0.046) between the groups after matching. A high CRP/albumin ratio (≥1.5) was significantly associated with a higher incidence of postoperative delirium (adjusted odds ratio [OR]: 2.11, 95 % confidence interval [CI]: 1.40-3.18, P < 0.001) and a higher rate of overall mortality (adjusted hazard ratio [HR]: 1.44, 95 % CI: 1.07-1.93, P = 0.015).

CONCLUSION

Preoperative CRP/albumin ratio might be an independent risk factor of postoperative delirium and surgical prognosis in elderly patients undergoing hip fracture surgery.

Correlation Analysis of Inflammatory Markers CRP and IL-6 and Postoperative Delirium (POD) in Elderly Patients: A Meta-Analysis of Observational Studies

Background

Postoperative delirium (POD) is very common in the elderly surgical population, and its occurrence is associated with multiple factors such as preoperative, intraoperative, and postoperative factors, and the increase of serum inflammatory markers such as C-reactive protein (CRP) and interleukin-6 (IL-6) is considered to be associated with the occurrence of POD, but the results of multiple studies are inconsistent. In this study, we investigated the correlation between inflammatory markers CRP and IL-6 and POD in elderly patients by literature search and meta-analysis.

Methods

We searched PubMed, Web of Science, the Cochrane library, Embase, Ovid, and Springer Link for cohort studies or case-control studies that investigated the factors involved in the occurrence of POD, used the Newcastle-Ottawa Scale (NOS) to assess the quality of the selected literature, and combined the differences in serum CRP and IL-6 levels between POD and non-POD patients after surgery to evaluate the predictive value of CRP and IL-6 for the occurrence of POD.

Results

This research comprised 16 papers for quantitative analysis, with a total of 2967 patients, 758 with POD and 2209 with non-POD. There were 16 cohort studies (100%) and 0 case-control studies (0%) across all the collected literatures; there were 15 prospective cohort studies and 1 retrospective cohort research. A meta-analysis revealed a statistically significant difference in serum IL-6 levels between POD patients after surgery and non-POD patients [MD = 115.68, 95% CI (25.70, 206.66), Z = 2.52, P = 0.012], as well as a statistically significant difference in serum CRP levels [MD = 27.67, 95% CI (12.77, 42.58), Z = 3.64, P = 0.0003]. Discussion. Early after surgery, serum IL-6 and CRP levels were considerably higher in POD patients than in non-POD patients, indicating that early serum inflammatory variables are likely to be predictors of POD. After surgery, the levels of the aforementioned inflammatory factors should be actively monitored to forecast the emergence of delirium, and active treatment should be used to limit the creation and release of the aforementioned inflammatory factors.

The C-reactive protein/albumin ratio predicts postoperative delirium in patients older than 60 years following total knee arthroplasty

Purpose

This study aimed to investigate the relationship between serum C-reactive protein (CRP)/Albumin ratio (CAR) and postoperative delirium (POD) in patients older than 60 years following total knee arthroplasty (TKA).

Methods

From January 2019 to January 2021, 268 patients were recruited in this prospective observational investigation. Patients with serum CRP, Alb, CAR, delirious status and delirious score were assessed. The effect of CRP, Alb, CAR on predicting delirium was assessed with the area under the receiver operating characteristic (ROC) curve (AUC).

Results

The study found that higher CRP level (P < 0.001), low Alb level (P < 0.001), and higher CAR (P < 0.001) were independently associated with POD. The AUC of CAR for POD was 0.782, with the cut-off value of 0.117, a sensitivity of 83.3% and a specificity of 65.9% respectively (P < 0.001), suggesting that CAR had moderate efficacy on predicting POD occurrence than CRP (AUC: 0.761) and Alb (AUC: 0.300). The results also showed that age, ASA and the operation time was an independent predictor for patients with POD.

Conclusions

Our findings demonstrated CAR may be an effective biomarker to predict postoperative delirium in patients over 60 years of age with TKA, which provides potential recommendations for early intervention in delirium care.

Clinical Predictors and Outcomes Associated with Postoperative Delirium Following Infrainguinal Bypass Surgery

OBJECTIVES

Postoperative delirium (POD) is common yet often underdiagnosed following vascular surgery. Elderly patients with advanced peripheral artery disease may be at particular risk for POD yet understanding of the clinical predictors and impact of POD is incomplete. We sought to identify POD predictors and associated resource utilization after infrainguinal lower extremity bypass.

METHODS

This single center retrospective analysis included all infrainguinal bypass cases performed for peripheral arterial disease from 2012-2020. The primary outcome was inpatient post-operative delirium. Delirium sequelae were also evaluated. Key secondary outcomes were length of stay, non-home discharge, readmission, 30-day amputation, postoperative myocardial infarction, mortality, and 2-year survival. Regression analysis was used to evaluate risk factors for delirium in addition to association with 2-year survival and amputation free survival.

RESULTS

Among 420 subjects undergoing infrainguinal lower extremity bypass, 105 (25%) developed POD. Individuals with POD were older and more likely to have non-elective surgery (p<0.05). On multivariable analysis, independent predictors of POD were age 60-89 years old, chronic limb threatening ischemia, female sex, and non-elective procedure. Consultations for POD took place for 25 cases (24%); 13 (52%) were with pharmacists, and only 4 (16%) resulted in recommendations. The average length of stay for those with POD was higher (17 days vs 9 days; p<.001). POD was associated with increased non-home discharge (61.8% vs 22.1%; p<.001), 30-day major amputation (6.7% vs 1.6%; p<0.01), 30-day postoperative myocardial infarction (11.4% vs 4.1%; p<0.01), and 90-day mortality (7.6% vs 2.9%; p=0.03). Survival at 2 years was lower in those with delirium (89% vs 75%; p<.001). In a Cox proportional hazards model, delirium was independently associated with decreased survival (HR=2.0; 95% CI=1.15-3.38; p=0.014) and decreased major-amputation free survival (HR=1.9; 95% CI=1.18-2.96; p=0.007).

CONCLUSIONS

Postoperative delirium is common following infrainguinal lower extremity bypass and is associated with other adverse post-operative outcomes and increased resource utilization, including increased hospital length of stay, non-home discharge, and worse 2-year survival. Future studies should evaluate the role of routine multidisciplinary care for high-risk patients to improve perioperative outcomes for vulnerable older adults undergoing infrainguinal lower extremity bypass.

Serum Biomarkers in Postoperative Delirium After Esophagectomy

BACKGROUND

Esophagectomy is associated with postoperative delirium, but its pathophysiology is not well defined. We conducted this study to measure the relationship among serum biomarkers of inflammation and neuronal injury and delirium incidence and severity in a cohort of esophagectomy patients.

METHODS

Blood samples were obtained from patients preoperatively and on postoperative days 1 and 3 and were analyzed for S100 calcium-binding protein B, C-reactive protein (CRP), interleukin (IL) 8 and IL-10, tumor necrosis factor-α, and insulin-like growth factor 1. Delirium was assessed twice daily using the Richmond Agitation Sedation Scale and Confusion Assessment Method for Intensive Care Unit. Delirium severity was assessed once daily with the Delirium Rating Scale-Revised-98.

RESULTS

Samples from 71 patients were included. Preoperative biomarker concentrations were not associated with postoperative delirium. Significant differences in change in concentrations from preoperatively to postoperative day 1 were seen in IL-8 (delirium, 38.6; interquartile range [IQR], 29.3-69.8; no delirium, 24.8; IQR, 16.0-41.7, P = .022), and IL-10 (delirium, 26.1; IQR, 13.9-36.7; no delirium, 12.4; IQR, 7.7-25.7; P = .025). Greater postoperative increase in S100 calcium-binding protein B (Spearman r = 0.289, P = .020) and lower levels of insulin-like growth factor 1 were correlated with greater delirium severity (Spearman r = -0.27, P = .040). Greater CRP change quartiles were associated with higher delirium incidence adjusting for severity of illness (odds ratio, 1.68; 95% confidence interval, 1.03-2.75; P = .037) or comorbidities (odds ratio, 1.70; 95% confidence interval, 1.05-2.76, P = .030).

CONCLUSIONS

Differences in change in serum CRP, IL-8, and IL-10 concentrations were associated with postoperative delirium, suggesting biomarker measurement early in the postoperative course is associated with delirium.

Accuracy of delirium risk factors in adult intensive care unit patients

OBJECTIVE

To assess the accuracy measurements for predisposing and precipitating Risk Factors for delirium in an adult Intensive Care Unit.

METHOD

Cohort, prospective study with patients over 18 who had been hospitalized for over 24 hours and were able to communicate. The patients were assessed once a day until the onset of delirium or permanence in the Intensive Care Unit. Instruments were employed to track delirium, characterize the sample, and identify the risk factors. Descriptive statistics was employed for sample characterization and accuracy tests for risk factors.

RESULTS

The included patients amounted to 102, 31 of which presented delirium. The predisposing predictive risk factors were hypoalbuminemia, American Society of Anesthesiology over three, severity, altered tissue perfusion, dehydration, and being a male, whereas precipitating predictive factors were physical restraint, infection, pharmacological agent, polypharmacy, anemia, altered renal function, dehydration, invasive devices, altered tissue perfusion and altered quality and quantity of sleep.

CONCLUSION

An accurate identification of predisposing and precipitating risk factors may contribute to planning preventive measures against delirium.

Progress of research in postoperative cognitive dysfunction in cardiac surgery patients: A review article

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a common complication of central nervous system in middle-aged and elderly patients after cardiac surgery. The purpose of this study was to review the progress in diagnosis, pathogenesis and risk factors and control strategy of POCD.

METHODS

A systematic literature search was conducted using Pubmed and EMBASE, using the Mesh terms and key words "POCD", "diagnostic criteria", "pathogenesis", "influencing factors" and "prevention strategies". Studies were retained for review after meeting strict inclusion criteria that included only prospective studies evaluating risk factors for POCD in patients who had elective cardiac surgery. Diagnosis of POCD needed to be confirmed using the Diagnostic and Statistical Manual of Montreal Cognitive Assessment (MoCA) Scale and other criteria.

RESULTS

"Twenty two articles were selected for inclusion. The incidence of POCD across the studies ranged from 9% to 54%. Multiple factors have been associated with the pathogenesis and increased risk of POCD, including neuroinflammation, dysfunction of cholinergic system, abnormal protein function (β-amyloid), old age, anesthetic, surgical and other factors."

CONCLUSIONS

POCD is a common complication after cardiac surgery in elderly. The highest POCD incidence was observed after open aortic, TAVI and CABG surgery. Age, cognitive function, depression, CPB and anesthetic use are leading risk factors. Further research is needed in determining interventions that will be effective in preventing and treating POCD in cardiac surgical setting.

Biomarkers in delirium: A systematic review

BACKGROUND

Delirium is a common neuropsychiatric disorder associated with prolonged hospital stays, and increased morbidity and mortality. Diagnosis is frequently missed due to varying disease presentation and lack of standardized testing. We examined biomarkers as diagnostic or prognostic indicators of delirium, and provide a rational basis for future studies.

METHOD

Systematic review of literature published between Jan 2000 and June 2019. Searches included: PubMed; Web of Science; CINAHL; EMBASE; COCHRANE and Medline. Additional studies were identified by searching bibliographies of eligible articles.

RESULTS

2082 relevant papers were identified from all sources. Seventy-three met the inclusion criteria, all of which were observational. These assessed a range of fourteen biomarkers. All papers included were in the English language. Assessment methods varied between studies, including: DSM criteria; Confusion Assessment Method (CAM) or CAM-Intensive Care Unit (ICU). Delirium severity was measured using the Delirium Rating Scale (DRS). Delirium was secondary to post-operative dysfunction or acute medical conditions.

CONCLUSION

Evidence does not currently support the use of any one biomarker. However, certain markers were associated with promising results and may warrant evaluation in future studies. Heterogeneity across study methods may have contributed to inconclusive results, and more clarity may arise from standardization of methods of clinical assessment. Adjusting for comorbidities may improve understanding of the pathophysiology of delirium, in particular the role of confounders such as inflammation, cognitive disorders and surgical trauma. Future research may also benefit from inclusion of other diagnostic modalities such as EEG as well as analysis of genetic or epigenetic factors.

Association between ankle brachial index and development of postoperative intensive care unit delirium in patients with peripheral arterial disease

Patients with vascular diseases are prone to developing postoperative delirium (POD). Ankle brachial index (ABI) is a non-invasive clinical indicator of lower-extremities peripheral arterial disease (PAD) and has been identified as an indicator of cognitive impairment. We investigated the association between ABI and POD. 683 PAD patients who underwent elective leg arterial bypass surgery between October 1998 and August 2019 were collected for retrospective analysis. Demographic information, comorbidities, preoperative ABI and the Rutherford classification within one month prior to surgery were obtained. POD was assessed using the Confusion assessment method -intensive care unit. Logistic regression and receiver operating characteristics (ROC) curve analysis were used to assess the association between ABI and POD. The mean value of ABI was significantly lower in patients with POD than it was those without POD. Older age, more medical comorbidities, longer length of surgery, decreased ABI, and higher Rutherford class were all significantly associated with POD. The area under ROC (0.74) revealed that ABI below 0.35 was associated with development of POD. Lower preoperative ABI was associated with POD in PAD patients who underwent arterial bypass surgery.

Association of Carotid Plaque and Serum Lipoprotein-Associated Phospholipase A2 (LP-PLA2) with Postoperative Delirium in Geriatric Patients Undergoing Hip Replacement: A Prospective Cohort Study

BACKGROUND The aim of this study was to investigate the relationships among carotid plaque (CP), serum lipoprotein-associated phospholipase (LP-PLA2), and POD in elderly patients. MATERIAL AND METHODS Sixty-two elderly patients undergoing hip replacement with spinal-epidural anesthesia were divided into CP and non-CP groups based on the preoperative presence or absence of carotid atherosclerotic plaques, as assessed by ultrasound. POD was diagnosed by means of the Confusion Assessment Method (CAM). Blood samples were collected (preoperatively, postoperatively, and postoperative day 2) for the assessment of serum LP-PLA2 by enzyme-linked immunosorbent assay. The CP group was further divided into POD and no-POD subgroups based on the occurrence of POD. RESULTS The incidence of POD was higher in the CP group than in the non-CP group (P0.05), it was higher in the CP group than in the non-CP group postoperatively and on postoperative day 2 (P0.05), but was significantly higher in the POD subgroup than in the no-POD subgroup on postoperative day 2 (P<0.05). Furthermore, the LP-PLA2 level on postoperative day 2 was an independent risk factor for POD (odds ratio: 1.03, 95% confidence interval: 1.00-1.07). CONCLUSIONS The preoperative presence of carotid plaque is closely associated with a higher incidence of POD. The potential mechanism may involve the increased expression of LP-PLA2 in the serum, which can lead to plaque destabilization and subsequent inflammatory cascades.

Preoperative Acute Pain Is Associated with Postoperative Delirium

Background

Studies have provided some evidence that pain is a risk factor for postoperative delirium (POD). Therefore, we investigated the relationship between preoperative pain and POD after noncardiac surgery.

Methods

POD was assessed with the Montreal Cognitive Assessment, and preoperative cognition was assessed with the Mini-Mental State Examination. Plasma C-reactive protein (CRP) was detected by enzyme-linked immunosorbent assay before surgery. Preoperative pain was classified by its duration before surgery as chronic pain (lasting more than 1 month), acute pain (lasting less than 1 month), or no pain (no obvious pain). Multiple linear regression was used to adjust for confounding.

Results

From October 15, 2018, through August 12, 2019, a total of 67 patients were randomized; 7 were excluded because they were discharged before the seventh postoperative day. The prevalence of POD was significantly higher in the acute pain group (13 of 20; 65%) than in the chronic pain group (5 of 20; 25%) or the no pain group (6 of 20; 30%) (P = 0.019), indicating that delirium is associated with preoperative acute pain. The plasma level of preoperative CRP was also higher in the acute pain group than in the other two groups (mean [interquartile range]: 10.7 [3.3, 29.3] vs 1 [0.5, 3.8]mg/l; P &lt; 0.001), suggesting that elevated preoperative plasma levels of CRP were associated with delirium.

Conclusions

Preoperative acute pain was associated with POD, and increased plasma levels of CRP provide a marker. In addition, we found that illiteracy and advanced age were risk factors for POD.

Preoperative Circulating MiR-210, a Risk Factor for Postoperative Delirium Among Elderly Patients with Gastric Cancer Undergoing Curative Resection

BACKGROUND

Postoperative delirium (POD) is a very common complication in elderly patients with gastric cancer (GC) and associated with poor prognosis. MicroRNAs (miRNAs) serve as key post-transcriptional regulators of gene expression via targeting mRNAs and play important roles in the nervous system. This study aimed to investigate the potential predictive role of miRNAs for POD.

METHODS

Elderly GC patients who were scheduled to undergo elective curative resection were consequently enrolled in this study. POD was assessed at 1 day before surgery and 1-7 days after surgery following the guidance of the 5th edition of Diagnostic and Statistical Manual of Mental Disorders (DSM V, 2013). The demographics, clinicopathologic characteristics and preoperative circulating miRNAs by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) were compared between patients with or without POD. Risk factors for POD were assessed via univariate and multivariate logistic regression analyses.

RESULTS

A total of 370 participants were enrolled, of which 63 had suffered from POD within postoperative 7 days with an incidence of 17.0%. Preoperative miR-210 was a predictor for POD with an area under the curve (AUC) of 0.921, a cut-off value of 1.67, a sensitivity of 95.11%, and a specificity of 92.06%, (P<0.001). In the multivariate logistic regression model, the relative expression of serum miR-210 was an independent risk factor for POD (OR: 3.37, 95%CI: 1.98-5.87, P=0.003).

CONCLUSIONS

In conclusion, the present study highlighted that preoperative miR-210 could serve as a potential predictor for POD in elderly GC patients undergoing curative resection.

Identification of distinct clinical phenotypes in mechanically ventilated patients with acute brain dysfunction using cluster analysis

Acute brain dysfunction (ABD) is a frequent and severe syndrome occurring in critically ill patients and early identification of high-risk patients is paramount. In the present analysis, we propose a clinically applicable model for early phenotype identification of ABD at the bedside in mechanically ventilated patients, improving the recognition of patients with prolonged ABD.Prospective cohort with 629 mechanically ventilated patients in two medical-surgical intensive care units at academic centers. We applied cluster analysis to identify phenotypes using clinical and biological data. We then tested the association of phenotypes and its respective clinical outcomes. We performed a validation on a new cohort of patients select on subsequent patients admitted to the participants intensive care units.A model with 3 phenotypes best described the study population. A 4-variable model including medical admission, sepsis diagnosis, simplified acute physiologic score II and basal serum C-reactive protein (CRP) accurately classified each phenotype (area under curve 0.82; 95% CI, 0.79-0.86). Phenotype A had the shorter duration of ABD (median, 1 day), while phenotypes B and C had progressively longer duration of ABD (median, 3 and 6 days, respectively; P < .0001). There was an association between the duration of ABD and the baseline CRP levels and simplified acute physiology score II score (sensitivity and specificity of 80%). To increase the sensitivity of the model, we added CRP kinetics. By day 1, a CRP < 1.0 times the initial level was associated with a shorter duration of ABD (specificity 0.98).A model based on widely available clinical variables could provide phenotypes associated with the duration of ABD. Phenotypes with longer duration of ABD (phenotypes B and C) are characterized by more severe inflammation and by significantly worse clinical outcomes.

Preoperative C-Reactive Protein/Albumin Ratio, a Risk Factor for Postoperative Delirium in Elderly Patients After Total Joint Arthroplasty

BACKGROUND

Postoperative delirium (POD), as an acute brain failure, is widely reported as a very common postoperative complication, and it is closely associated with increased morbidity and mortality. This study aimed to investigate potential risk factors including C-reactive protein/albumin ratio (CAR) for POD in elderly subjects after total joint arthroplasty (TJA).

METHODS

A total of 272 elderly patients (aged 65∼85 years) who were scheduled to undergo elective TJA with epidural anesthesia were consecutively recruited. The data of baseline characteristics, operation-associated indexes, and preoperative laboratory tests were collected. POD assessment was performed daily within postoperative 7 days. Receiver operating characteristic curve analysis was utilized for evaluating the predictive and cut-off value of CAR for POD. Risk factors for POD were evaluated by the binary univariate and multivariate logistic regression analyses.

RESULTS

Within postoperative 7 days, there were 55 patients who had suffered POD with an incidence of 20.2% (55/272). The area under the curve of CAR for POD was 0.804, with the cut-off value of 2.35, a sensitivity of 66.82%, and a specificity of 80.00%, respectively (95% confidence interval [CI]: 0.737-0.872, P < .001). Age (odds ratio: 2.02, 95% CI: 1.03-3.96, P = .038) and preoperative CAR level (odds ratio: 3.04, 95% CI: 1.23-7.23, P = .016) were 2 independent risk factors for POD in elderly subjects undergoing TJA.

CONCLUSIONS

Preoperative CAR level may be a promising predictor for POD in elderly subjects following TJA.

The trajectory of C-reactive protein serum levels in older hip fracture patients with postoperative delirium

OBJECTIVES

Important precipitating risk factors for delirium such as infections, vascular disorders, and surgery are accompanied by a systemic inflammatory response. Systemic inflammatory mediators can induce delirium in susceptible individuals. Little is known about the trajectory of systemic inflammatory markers and their role in the development and outcome of delirium.

METHODS

This is a prospective cohort study of older patients undergoing acute surgery for hip fracture. Baseline characteristics were assessed preoperatively. During hospital admission, presence of delirium was assessed daily according to the Confusion Assessment Method criteria. This study compared the trajectory of serum levels of the C-reactive protein (CRP) between people with and without postoperative delirium. Blood samples were taken at baseline and at postoperative day 1 through postoperative day 5.

RESULTS

Forty-one out of 121 patients developed postoperative delirium after hip fracture surgery. Longitudinal analysis of the trajectory of serum CRP levels using the Generalized Estimating Equations (GEE) method identified that higher CRP levels were associated with postoperative delirium. CRP levels were higher from postoperative day 2 through postoperative day 5. No significant differences in serum CRP levels were found when we compared patients with short (1-2 days) and more prolonged delirium (3 days or more).

CONCLUSIONS

Delirium is associated with an increased systemic inflammatory response, and our results suggest that CRP plays a role in the underlying (inflammatory-vascular) pathological pathway of postoperative delirium.

Dexmedetomidine suppresses sevoflurane anesthesia-induced neuroinflammation through activation of the PI3K/Akt/mTOR pathway

Background

Sevoflurane, an inhalational general anesthetic, has become one of the most widely used inhalational anesthetics in surgery. However, previous studies have found that sevoflurane anesthesia can trigger an inflammatory response, resulting in secondary damage. Dexmedetomidine (DEX), a highly-selective α adrenergic receptor agonist, is widely used as an anesthetic adjuvant in the clinic. In this study we investigated whether DEX was able to suppress sevoflurane-induced neuroinflammation.

Methods

The aim was to determine the mechanism of action of the suppressive effect of DEX using a rat model. Rats were randomly divided into a control group (n = 10), low-dose sevoflurane group (L-Sev; n = 10), high-dose sevoflurane group (H-Sev; n = 10), vehicle group (n = 10), DEX group (n = 10) and DEX + LY294002 (a specific inhibitor of PI3K) group (n = 10). The rats in vehicle, DEX and DEX + LY294002 groups were in the presence of high-dose sevoflurane exposure. Western blotting was used to measure the expression of proinflammatory cytokines (IL-6, IL-8, TNF-α) and the activity level of the phosphatidylinositol 3-hydroxy kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway.

Results

We found that sevoflurane anesthesia induced an increase in the levels of pro-inflammatory cytokines, while decreasing activation of the PI3K/Akt/mTOR pathway in both the cortex and hippocampus of rats. Treatment with DEX reduced pro-inflammatory cytokine levels and prevented inactivation of the PI3K/Akt/mTOR pathway. Moreover, LY294002, an inhibitor of the PI3K/Akt/mTOR pathway, reduced the anti-inflammatory activity of DEX.

Conclusions

These data suggest that the PI3K/Akt/mTOR pathway contributes to sevoflurane-induced neuroinflammation and that activation of PI3K/Akt/mTOR signaling by DEX could help reduce the neuroinflammatory effects of sevoflurane.

The Association Between C-Reactive Protein and Postoperative Delirium Differs by Catechol-O-Methyltransferase Genotype

OBJECTIVE

Catechol-O-methyltransferase (COMT), a key enzyme in degrading catecholamines associated with the stress response, may influence susceptibility to delirium. Individuals with the COMT (rs4680) Val/Val genotype (designated "warriors") withstand the onset of neuropsychiatric disorders and cognitive decline, whereas individuals with Met/Met and Val/Met genotypes ("nonwarriors") are more susceptible to these conditions. We evaluated whether COMT genotype modifies the established association between acute phase reactant (stress marker) C-reactive protein (CRP) and postoperative delirium.

METHODS

This was a prospective cohort study conducted at two academic medical centers. The study involved 547 patients aged 70 or older undergoing major noncardiac surgery. We collected blood, extracted DNA, and performed COMT genotyping using allele-specific polymerase chain reaction assays, considering warriors versus nonwarriors. High plasma CRP, measured on postoperative day 2 using enzyme-linked immunosorbent assay, was defined by the highest sample-based quartile (≥234.12 mg/L). Delirium was determined using the Confusion Assessment Method, augmented by a validated chart review. We used generalized linear models adjusted for age, sex, surgery type, and race/ethnicity, stratified by COMT genotype, to determine whether the association between CRP and delirium differed by COMT.

RESULTS

Prevalence of COMT warriors was 26%, and postoperative delirium occurred in 23%. Among COMT warriors, high CRP was not associated with delirium (relative risk [RR] 1.0, 95% confidence interval [CI] 0.4-2.6). In contrast, among nonwarriors, we found the expected relationship of high CRP and delirium (RR 1.5, 95% CI 1.1-2.2).

CONCLUSION

COMT warriors may be protected against the increased risk of delirium associated with high CRP on postoperative day 2. With further confirmation, COMT genotype may help target interventions for delirium prevention in the vulnerable nonwarrior group.

Anesthetic Immunomodulation of the Neuroinflammation in Postoperative Cognitive Dysfunction

Postoperative delirium and cognitive dysfunction are phenomena that are associated with increases in morbidity, mortality, and resource utilization after surgery. This review scrutinized a number of studies in order to better characterize the biochemical basis for associated cognitive dysfunction and delirium, with particular focus paid to the interactions of the cholinergic system with innate immunity and how the modulation of the immune system contributes to associated neuroinflammation. Despite the clinical impact of postoperative cognitive dysfunction, evidence-based protocols for the prevention and treatment of these disorders are still lacking. Several previous trials have attempted to prevent or treat clinical manifestation by modulation of the cholinergic system with acetylcholinesterase inhibitors, the results of which have been largely ambiguous at best. As the biochemical basis of postoperative cognitive dysfunction becomes more clearly defined, future research into therapeutics based on immune modulation and treatment of neuroinflammation may prove to be very promising.

Postoperative delirium in elderly patients with critical limb ischemia undergoing major leg amputation: a retrospective study

BACKGROUND

Critical limb ischemia has been identified as a risk factor for the incidence of postoperative delirium in elderly patients. Limb amputation is the last option in critical limb ischemia treatments. We investigated the incidence and predisposing factors of postoperative delirium in patients undergoing major leg amputation.

METHODS

From January 2012 to December 2016, 121 patients aged over 60 years who had undergone major leg amputation were enrolled in this study. Various factors related to the patients' outcomes were assessed, including demographic, preoperative laboratory, anesthetic, surgical, and postoperative indicators.

RESULTS

Twenty two patients were excluded and 99 patients were assigned to either the delirium group or no delirium group. Forty of them (40%) developed a delirium during 30 days postoperatively. Univariate analysis implied that end-stage renal disease on hemodialysis, alcohol consumption, C-reactive protein, staying in an intensive care unit (ICU), duration of an ICU stay, occurrence of complications, and mortality during six months, were the factors that accounted for significant differences between the two groups. In multivariate analysis, three factors were significantly related to the development of delirium: mortality during six months (odds ratio [OR] = 13.86, 95% CI [2.10-31.90]), alcohol (OR = 8.18, 95% CI [1.13-16.60]), and hemodialysis (OR = 4.34, 95% CI [2.06-93.08]).

CONCLUSIONS

Approximately 40% of the elderly patients suffered from postoperative delirium in major leg amputation. Identifying those with risk factors for postoperative delirium and intervening at the early stage will be of great benefit in major leg amputations for the elderly population.

Preoperative C-Reactive Protein as a Risk Factor for Postoperative Delirium in Elderly Patients Undergoing Laparoscopic Surgery for Colon Carcinoma

Background

Postoperative delirium (POD) is a very common complication in operative disciplines, especially in those elderly patients after cardiac surgery. This study aimed to investigate the relationship between C-reactive protein (CRP) and POD in elderly patients undergoing laparoscopic surgery for colon carcinoma.

Methods

160 elderly patients scheduled to undergo selective laparoscopic surgery for colon carcinoma were prospectively recruited in this present study. The preoperative demographic and medical characteristics, intraoperative variables, and postoperative complications were all recorded in detail. POD assessment was performed once a day for the first 3 days and at 7th day after surgery, respectively. CRP concentrations preoperatively and on postoperative days 1, 2, and 3 were measured by using human enzyme linked immunosorbent assay (ELISA).

Results

Of all the 160 enrolled patients, 39 had suffered POD with a POD incidence of 24.4% within the first week after the operation. The univariate analysis and multiple logistic regression analysis suggested preoperative CRP concentrations as the only independent predicator for POD in patients undergoing laparoscopic surgery for colon carcinoma (OR: 5.87; 95% CI: 2.22-11.4; P = 0.018).

Conclusions

This present study highlighted the predictive role of preoperative CRP concentrations for POD in elderly patients undergoing laparoscopic surgery for colon carcinoma.

A systematic review and meta-analysis of factors for delirium in vascular surgical patients

BACKGROUND

Delirium is a common syndrome responsible for a large burden of morbidity and mortality. In surgical settings, research into risk factors for postoperative delirium has largely focused on elective orthopedic patients. We performed a systematic review and meta-analysis to evaluate the evidence surrounding risk factors for delirium in vascular surgical populations.

METHODS

Two independent reviewers searched five databases (MEDLINE, Web of Science, Embase, Cumulative Index to Nursing and Allied Health Literature, and PsycINFO) from January 1987 to December 2015. We included primary research studies for incident delirium that used validated delirium assessment tools in exclusively vascular surgical populations.

RESULTS

We identified 16 studies (3817 patients) that met the inclusion criteria. There was substantial clinical heterogeneity in the populations included under a heading of "vascular surgery." Studies were high quality, with an average Newcastle-Ottawa Scale score of 6.9. Summary incidence of delirium was 23.4% (range, 4.8%-39%). Across all studies, 157 separate risk factors were examined. Ten of the included studies used multivariable models in their analysis of risk factors. Meta-analysis of risk factors with data from more than three studies identified the following factors as conferring an increased risk of delirium: American Society of Anesthesiologists score >2 (odds ratio [OR], 3.44), renal failure (OR, 2.09), previous stroke (OR, 1.87), history of neurologic comorbidity (OR, 1.57), and male sex (OR, 1.30). Delirious patients were older (mean difference [MD], +4.99 years), had lower preoperative hemoglobin levels (MD, -0.66 g/dL), and stayed longer in intensive care units (MD, +1.06 days).

CONCLUSIONS

Delirium is common in vascular surgery settings. Meta-analysis has identified significant risk factors relating to the patient, the presentation, and the pathway of care. Better understanding of these risk factors may help in prediction, prevention, and early identification of delirium.

Risk factors for postoperative delirium in patients undergoing vascular surgery

OBJECTIVE

Postoperative delirium (PODE) remains a common complication after vascular surgery procedures although the exact pathogenesis remains unclear, mainly because of its multifactorial character. The aim of this systematic review was to evaluate pooled data on potential risk factors for PODE in patients undergoing vascular surgery procedures.

METHODS

A systematic literature review was conducted conforming to established criteria to identify eligible articles published from 1990 to 2016. Eligible studies evaluated potential risk factors for PODE after vascular surgery procedures, using both univariate and multivariate analysis. PODE was defined as a disturbance of consciousness with reduced ability to focus, sustain, or shift attention after vascular surgery procedures and was diagnosed in all studies using well-established criteria. Only risk factors reported in at least four studies were included in this review. Pooled results were calculated, and further multivariate regression analysis was conducted.

RESULTS

Overall, nine studies (published from 2003 to 2015) including 2388 patients in total were evaluated (457 with and 1931 without PODE). Patients with PODE were older (73.27 vs 69.87 years; P < .0001) and showed a higher male sex rate (78.1% vs 73.5%; P = .043). Open aortic surgery was the most frequent procedure in this analysis, followed by lower limb revascularization. Patients with PODE also showed higher rates of diabetes mellitus, hypertension, cardiac disease, and neurologic disease; lower hemoglobin level; larger duration of surgery; longer hospital and intensive care unit stay; and higher blood loss. Mean age (odds ratio [OR], 3.44; 95% confidence interval [CI], 2.933-4.034; P < .0001), hypertension (OR, 1.94; 95% CI, 1.469-2.554; P < .0001), cardiac disease (OR, 3.16; 95% CI, 2.324-4.284; P < .0001), open aortic surgery (OR, 1.74; 95% CI, 1.421-2.143; P < .0001), blood loss (OR, 1.01; 95% CI, 1.007-1.010; P < .0001), hospital stay (OR, 2.26; 95% CI, 1.953-2.614; P <. 0001), and intensive care unit stay (OR, 6.12; 95% CI, 4.699-7.957; P < .0001) were identified as the strongest risk predictors for PODE, followed by male sex, diabetes mellitus, neurologic disease, and history of smoking. However, body mass index, renal failure, preoperative hemoglobin level, and general anesthesia were not found to be risk factors for PODE in such patients.

CONCLUSIONS

This study has confirmed that PODE after vascular surgery procedures is a multifactorial disease, and several independent risk factors have been identified. However, pooled data regarding the effect of PODE on primary outcomes after vascular surgery procedures are still lacking. The results of this review could contribute to the designation of future prediction models and improve prevention of PODE in these patients.

High C-Reactive Protein Predicts Delirium Incidence, Duration, and Feature Severity After Major Noncardiac Surgery

OBJECTIVES

To examine associations between the inflammatory marker C-reactive protein (CRP) measured preoperatively and on postoperative day 2 (POD2) and delirium incidence, duration, and feature severity.

DESIGN

Prospective cohort study.

SETTING

Two academic medical centers.

PARTICIPANTS

Adults aged 70 and older undergoing major noncardiac surgery (N = 560).

MEASUREMENTS

Plasma CRP was measured using enzyme-linked immunosorbent assay. Delirium was assessed from Confusion Assessment Method (CAM) interviews and chart review. Delirium duration was measured according to number of hospital days with delirium. Delirium feature severity was defined as the sum of CAM-Severity (CAM-S) scores on all postoperative hospital days. Generalized linear models were used to examine independent associations between CRP (preoperatively and POD2 separately) and delirium incidence, duration, and feature severity; prolonged hospital length of stay (LOS, >5 days); and discharge disposition.

RESULTS

Postoperative delirium occurred in 24% of participants, 12% had 2 or more delirium days, and the mean ± standard deviation sum CAM-S was 9.3 ± 11.4. After adjusting for age, sex, surgery type, anesthesia route, medical comorbidities, and postoperative infectious complications, participants with preoperative CRP of 3 mg/L or greater had a risk of delirium that was 1.5 times as great (95% confidence interval (CI) = 1.1-2.1) as that of those with CRP less than 3 mg/L, 0.4 more delirium days (P < .001), more-severe delirium (3.6 CAM-S points higher, P < .001), and a risk of prolonged LOS that was 1.4 times as great (95% CI = 1.1-1.8). Using POD2 CRP, participants in the highest quartile (≥235.73 mg/L) were 1.5 times as likely to develop delirium (95% CI = 1.0-2.4) as those in the lowest quartile (≤127.53 mg/L), had 0.2 more delirium days (P < .05), and had more severe delirium (4.5 CAM-S points higher, P < .001).

CONCLUSION

High preoperative and POD2 CRP were independently associated with delirium incidence, duration, and feature severity. CRP may be useful to identify individuals who are at risk of developing delirium.

Prevalence and risk factors for postoperative delirium in total joint arthroplasty patients: A prospective study

BACKGROUND

The aim of this prospective study was to investigate the incidence and clinical features of delirium after total joint arthroplasty, and to establish the potential risk factors for postoperative delirium.

METHODS

A total of 212 consecutive patients undergoing hip or knee arthroplasty, who met the inclusion and exclusive criteria were enrolled. The general characteristics, preoperative and postoperative hematological variables were documented respectively. According to the presence of delirium, all patients were divided into the delirium group and non-delirium group. Univariate and multivariate logistic regression were performed to identify the possible predictors for postoperative delirium.

RESULTS

At a minimum of 6months of follow-up, 35 patients were observed with postoperative delirium at an estimated total incidence of 16.5%. The incidence of delirium was statistically higher in hip arthroplasty (22.8%) than that in knee arthroplasty (7.1%). The multivariate regression analysis identified older age (OR=1.590, P=0.023), a history of stroke (OR=190.23, P=0.036), preoperative PaO₂ (OR=1.277, P=0.018) and equivalent fentanyl dose (OR=1.010, P=0.012) as the predictive factors for postoperative delirium after total joint arthroplasty.

CONCLUSIONS

The incidence of postoperative delirium after total joint arthroplasty is higher than expected. Based on our findings, we suggest that the surgeons should focus on those patients who have these risk factors and ensure the appropriate management to avoid postoperative delirium.

Higher C-Reactive Protein Levels Predict Postoperative Delirium in Older Patients Undergoing Major Elective Surgery: A Longitudinal Nested Case-Control Study

BACKGROUND

Delirium is a common, morbid, and costly postoperative complication. We aimed to identify blood-based postoperative delirium markers in a nested case-control study of older surgical patients using a proteomics approach followed by enzyme-linked immunosorbent assay (ELISA) validation.

METHODS

The Successful Aging after Elective Surgery study enrolled dementia-free adults ≥70 years old undergoing major scheduled noncardiac surgery (N = 566; 24% delirium). Plasma was collected at four time points: preoperative, postanesthesia care unit, postoperative day 2, and 1 month postoperative. Matched pairs were selected for the independent discovery (39 pairs) and replication cohorts (36 pairs), which were subsequently combined into the pooled cohort (75 pairs). Isobaric tags for relative and absolute quantitation-based relative quantitation mass spectrometry proteomics were performed to identify the strongest delirium-related protein, which was selected for ELISA validation. Using the ELISA results, statistical analyses using nonparametric signed rank tests were performed in all cohorts examining the association between the identified protein and delirium.

RESULTS

C-reactive protein emerged from the proteomics analysis as the strongest delirium-related protein. Validation by ELISA confirmed that compared with controls, cases had significantly higher C-reactive protein levels in the discovery, replication, and pooled cohorts at the preoperative (median paired difference [MPD] 1.97 mg/L [p < .05], 0.29 mg/L, 1.56 mg/L [p < .01]), postanesthesia care unit (MPD 2.83 mg/L, 2.22 mg/L [p < .05], 2.53 mg/L [p < .01]) and postoperative day 2 (MPD 71.97 mg/L [p < .01], 35.18 mg/L [p < .05], 63.76 mg/L [p < .01]) time points, but not 1 month postoperative (MPD 2.72 mg/L, -0.66 mg/L, 1.10 mg/L).

CONCLUSIONS

Elevated preoperative and postoperative plasma levels of C-reactive protein were associated with delirium, suggesting that a preinflammatory state and heightened inflammatory response to surgery are potential pathophysiologic mechanisms of delirium.

Risk Factors for Delirium During Acute and Subacute Stages of Various Disorders in Patients Admitted to Rehabilitation Units

OBJECTIVE

To assess the risk factors for delirium in patients admitted to a rehabilitation unit for acute or subacute neurological or musculoskeletal disorders.

METHODS

We reviewed the medical records of 537 patients admitted to a rehabilitation unit and selected 398 patients in the acute or subacute stage of various neurological or musculoskeletal disorders. Among them, patients who had suffered from delirium were categorized into the delirium group (n=65), and the other patients were categorized into the non-delirium group (n=333). As potential risk factors for delirium, the patients' diagnosis, underlying disease, demographic data, hospital stay duration, surgery, and laboratory findings were reviewed, and the differences between the two groups with respect to independent risk factors were analyzed.

RESULTS

The average age in the delirium group was higher; the hospital stay and pre-transfer periods were longer. A large proportion of the patients were admitted for musculoskeletal disorders, and many patients had diabetes mellitus, dementia, and depression as underlying diseases. Laboratory tests revealed increases in the white blood cells (WBC), glucose, blood urea nitrogen (BUN), total bilirubin, aspartate transaminase (AST), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) levels in the delirium group, while the hemoglobin, calcium, phosphorus, protein, albumin, and potassium levels were decreased. Depression, musculoskeletal disorders, traumatic brain injury, elevated WBC, BUN, AST, and CRP levels, and decreased potassium and phosphorus levels were identified as independent risk factors for delirium.

CONCLUSION

Risk factors treatable before delirium onset were identified in rehabilitation patients in acute and subacute stages of various disorders. Early diagnosis and prevention of these risk factors could decrease delirium occurrence and increase rehabilitation effectiveness.

Risk factors of post-operative delirium after elective vascular surgery in the elderly: A systematic review

BACKGROUND

Postoperative delirium is a common and serious adverse event in the elderly patient and is associated with significant morbidity and mortality. It is of great importance to identify patients at risk for delirium, in order to focus preventive strategies. The aim of this article is to systematically review current available literature on pre-operative risk factors for delirium after vascular surgery.

METHODS

A systematic literature search was conducted using PubMed and EMBASE, using the MeSH terms and key words "delirium", "surgery" and "risk factor". Studies were retained for review after meeting strict inclusion criteria that included only prospective studies evaluating risk factors for delirium in patients who had elective vascular surgery. Diagnosis of delirium needed to be confirmed using the Diagnostic and Statistical Manual of Mental Disorders (DSM) or ICD-10.

RESULTS

Fifteen articles were selected for inclusion, incidence of delirium across the studies ranged from 5% to 39%. Many factors have been associated with increased risk of delirium, including age, cognitive impairment, comorbidity, depression, smoking, alcohol, visual and hearing impairment, ASA-score, biochemical abnormalities, operative strategies and blood loss.

CONCLUSIONS

Delirium is a common complication after elective vascular surgery in elderly. The highest delirium incidence was observed after open aortic surgery as well as after surgery for critical limb ischemia. A picture starts to form of which predisposing factors lead to increased risk of delirium. The leading risk factors consistently identified in this systematic review were advanced age and cognitive impairment. Multi-disciplinary specialist-led interventions in the preoperative phase could decrease incidence and severity of delirium and should be focused on identified high-risk patients.

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

Objective

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

Methods

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

Results

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

Conclusions

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

The major risk factors for delirium in a clinical setting

OBJECTIVE

We aimed to determine the major risk factors for the development of delirium in patients at a single general hospital by comparison with a control group.

SUBJECTS AND METHODS

We reviewed the medical records of 260 delirium patients and 77 control patients. We investigated age, sex, and risk factors for delirium in the total delirium group (n=260), the delirium medical subgroup (n=142), and the delirium surgical subgroup (n=118). Logistic regression analysis adjusting for age and sex was performed to identify the odds ratio.

RESULTS

The mean age and the percentage of males were significantly higher in the delirium group compared with the control group (68.9 vs 54.3 years and 70% vs 41.6%, respectively). Risk factors for the delirium group were lower plasma albumin, hypertension, mechanical ventilation, and antipsychotic drug use. Plasma sodium level and hypertension were important risk factors for the delirium medical subgroup. Stroke history, hypertension, ICU care, and medication were important risk factors for the delirium surgical subgroup.

CONCLUSION

Lower plasma albumin, hypertension, mechanical ventilation, and antipsychotic drug use are important risk factors for delirium.

Cytokines and Postoperative Delirium in Older Patients Undergoing Major Elective Surgery

BACKGROUND

A proinflammatory state has been associated with several age-associated conditions; however, the inflammatory mechanisms of delirium remain poorly characterized.

METHODS

Using the Successful Aging after Elective Surgery Study of adults age ≥70 undergoing major noncardiac surgery, 12 cytokines were measured at four timepoints: preoperative, postanesthesia care unit, postoperative day 2 (POD2) and 30 days later (POD1M). We conducted a nested, longitudinal matched (on age, sex, surgery type, baseline cognition, vascular comorbidity, and Apolipoprotein E genotype) case-control study: delirium cases and no-delirium controls were selected from the overall cohort (N = 566; 24% delirium). Analyses were independently conducted in discovery, replication, and pooled cohorts (39, 36, 75 matched pairs, respectively). Nonparametric signed-rank tests evaluating differences in cytokine levels between matched pairs were used to identify delirium-associated cytokines.

RESULTS

In the discovery and replication cohorts, matching variables were similar in cases and controls. Compared to controls, cases had (*p < .05, **p < .01) significantly higher interleukin-6 on POD2 in the discovery, replication, and pooled cohorts (median difference [pg/mL] 50.44**, 20.17*, 39.35**, respectively). In the pooled cohort, cases were higher than controls for interleukin-2 (0.99*, 0.77*, 1.07**, 0.73* at preoperative, postanesthesia care unit, POD2, POD1M, respectively), vascular endothelial growth factor (4.10* at POD2), and tumor necrosis factor-alpha (3.10* at POD1M), while cases had lower interleukin-12 at POD1M (-4.24*).

CONCLUSIONS

In this large, well-characterized cohort assessed at multiple timepoints, we observed an inflammatory signature of delirium involving elevated interleukin-6 at POD2, which may be an important disease marker for delirium. We also observed preliminary evidence for involvement of other cytokines.

Biomarkers of postoperative delirium and cognitive dysfunction

Elderly surgical patients frequently experience postoperative delirium (POD) and the subsequent development of postoperative cognitive dysfunction (POCD). Clinical features include deterioration in cognition, disturbance in attention and reduced awareness of the environment and result in higher morbidity, mortality and greater utilization of social financial assistance. The aging Western societies can expect an increase in the incidence of POD and POCD. The underlying pathophysiological mechanisms have been studied on the molecular level albeit with unsatisfying small research efforts given their societal burden. Here, we review the known physiological and immunological changes and genetic risk factors, identify candidates for further studies and integrate the information into a draft network for exploration on a systems level. The pathogenesis of these postoperative cognitive impairments is multifactorial; application of integrated systems biology has the potential to reconstruct the underlying network of molecular mechanisms and help in the identification of prognostic and diagnostic biomarkers.

Predicting postoperative delirium after vascular surgical procedures

OBJECTIVE

The objective of this study was to determine the incidence of and specific preoperative and intraoperative risk factors for postoperative delirium (POD) in electively treated vascular surgery patients.

METHODS

Between March 2010 and November 2013, all vascular surgery patients were included in a prospective database. Various preoperative, intraoperative, and postoperative risk factors were collected during hospitalization. The primary outcome variable was the incidence of POD. Secondary outcome variables were any surgical complication, hospital length of stay, and mortality.

RESULTS

In total, 566 patients were prospectively evaluated; 463 patients were 60 years or older at the time of surgery and formed our study cohort. The median age was 72 years (interquartile range, 66-77), and 76.9% were male. Twenty-two patients (4.8%) developed POD. Factors that differed significantly by univariate analysis included current smoking (P = .001), increased comorbidity (P = .001), hypertension (P = .003), diabetes mellitus (P = .001), cognitive impairment (P < .001), open aortic surgery or amputation surgery (P < .001), elevated C-reactive protein level (P < .001), and blood loss (P < .001). Multivariate logistic regression analysis revealed preoperative cognitive impairment (odds ratio [OR], 16.4; 95% confidence interval [CI], 4.7-57.0), open aortic surgery or amputation surgery (OR, 14.0; 95% CI, 3.9-49.8), current smoking (OR, 10.5; 95% CI, 2.8-40.2), hypertension (OR, 7.6; 95% CI, 1.9-30.5) and age ≥80 years (OR, 7.3; 95% CI, 1.8-30.1) to be independent predictors of the occurrence of POD. The combination of these parameters allows us to predict delirium with a sensitivity of 86% and a specificity of 92%. The area under the curve of the corresponding receiver operating characteristics was 0.93. Delirium was associated with longer hospital length of stay (P < .001), more frequent and increased intensive care unit stays (P = .008 and P = .003, respectively), more surgical complications (P < .001), more postdischarge institutionalization (P < .001), and higher 1-year mortality rates (P = .0026).

CONCLUSIONS

In vascular surgery patients, preoperative cognitive impairment and open aortic or amputation surgery were highly significant risk factors for the occurrence of POD. In addition, POD was significantly associated with a higher mortality and more institutionalization. Patients with these risk factors should be considered for high-standard delirium care to improve these outcomes.