Preoperative cognitive dysfunction in older elective noncardiac surgical patients in South Africa

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

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

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

AIM

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

DESIGN

A systematic review.

METHODS

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

RESULTS

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

PATIENT OR PUBLIC CONTRIBUTION

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

Research progress of postoperative cognitive dysfunction in cardiac surgery under cardiopulmonary bypass

Cardiopulmonary bypass (CPB) is often used in cardiothoracic surgery because its nonphysiological state causes pathophysiological changes in the body, causing multiorgan and multitissue damage to varying degrees. Postoperative cognitive dysfunction (POCD) is a common central nervous system complication after cardiac surgery. The etiology and mechanism of POCD are not clear. Neuroinflammation, brain mitochondrial dysfunction, cerebral embolism, ischemia, hypoxia, and other factors are related to the pathogenesis of POCD. There is a close relationship between CPB and POCD, as CPB can cause inflammation, hypoxia and reperfusion injury, and microemboli formation, all of which can trigger POCD. POCD increases medical costs, seriously affects patients' quality of life, and increases mortality. Currently, there is a lack of effective treatment methods for POCD. Commonly used methods include preoperative health management, reducing inflammation response during surgery, preventing microemboli formation, and implementing individualized rehabilitation programs after surgery. Strengthening preventive measures can minimize the occurrence of POCD and its adverse effects.

Effects of Different Injection Rates of Propofol on Postoperative Cognition in Elderly Patients Undergoing Laparoscopic Inguinal Hernia Repair

Purpose

This study aimed to explore the effects of different injection rates of propofol on postoperative cognition in elderly patients undergoing laparoscopic inguinal hernia repair.

Methods

A total of 180 elderly patients who planned to undergo laparoscopic inguinal hernia repair were randomly divided into three groups: slow injection of propofol (V_S-Group, 30 mg kg^-1 h^-1); medium injection of propofol (V_M-Group, 100 mg kg^-1 h^-1) or fast injection of propofol (V_F-Group, 300 mg kg^-1 h^-1). Propofol was induced by microinfusion pump, and the depth of anesthesia was monitored by bispectral index (BIS). Propofol and remifentanil were continuously infused during anesthesia maintenance and adjusted according to BIS. The primary outcome was the use of the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) to measure the incidence of postoperative cognitive decline (POCD) in elderly patients on the first and seventh postoperative day. Secondary outcomes included induced dose of propofol, incidence of burst suppression and maximum electroencephalographic (EEG) effect of propofol (BIS-min) during induction.

Results

The incidence of POCD on the first and seventh day postoperatively was similar among the three groups (P > 0.05). However, with the increase of propofol injection rate, induced dose of propofol, incidence of burst suppression and BIS-min during induction, the number of patients requiring vasoactive agents were significantly increased (P < 0.001). Multivariate regression analysis showed that the brief duration of burst suppression during induction did not affect the occurrence of POCD, while age and duration of hospitalization were risk factors for POCD.

Conclusion

For elderly patients undergoing laparoscopic inguinal hernia repair, lowering the injection rate of propofol (such as 30 mg kg^-1 h^-1) cannot decrease the incidence of early POCD, but reduces induction dose of propofol and use of vasoactive drugs, making the patient's hemodynamics more stable.

Prevalence of pre-operative undiagnosed cognitive impairment and its association with handgrip strength, oral hygiene, and nutritional status in older elective surgical patients in Japan

PURPOSE

Preoperative cognitive impairment is a significant factor influencing post-operative delirium. We have been performing routine pre-operative comprehensive assessments, including evaluation of cognitive function, handgrip strength, oral hygiene, and nutritional status, in patients aged ≥ 65 years since April 2021. This study aimed to examine the completion rate of pre-operative comprehensive assessment and assess the prevalence of pre-operative undiagnosed cognitive impairment.

METHODS

In this prospective observational study including patients aged ≥ 65 years scheduled for elective surgery with general or regional anesthesia, cognitive impairment was defined as a Mini-Cog score ≤ 2, and its associations with handgrip strength, oral hygiene, and nutritional status were evaluated. Oral hygiene and nutritional status were assessed using an oral frailty self-checklist and the Mini Nutritional Assessment-Short Form, respectively. The incidence of pre-operative undiagnosed cognitive impairment was estimated, and its associated factors were explored with multiple logistic regression.

RESULTS

Among 331 eligible patients, the completion rate was 97.7% (305/312). The mean age was 74.8 years, and 13.1% (40/305) (95% confidence interval [CI], 9.7-17.3%) of the patients had pre-operative undiagnosed cognitive impairment. Multiple logistic regression revealed that handgrip strength (odds ratio [OR] = 0.94, 95%CI = 0.89-0.99) and oral frailty self-checklist score (OR = 1.19, 95%CI = 1.02-1.40) were associated with pre-operative undiagnosed cognitive impairment, while the Mini Nutritional Assessment-Short Form score was not significantly associated (OR = 0.97, 95%CI = 0.82-1.14).

CONCLUSIONS

Preoperative comprehensive assessment was feasible. The prevalence of pre-operative undiagnosed cognitive impairment was 13%, and poor handgrip strength and worse oral hygiene were significantly associated factors.

Identification of individuals at risk for postoperative cognitive dysfunction (POCD)

Postoperative cognitive dysfunction (POCD) is common, occurring in around 10-54% of individuals within first few weeks after surgery. Although the majority of POCD is less commonly persistent later than 3 months following surgery, the condition increases length of stay (LOS), mortality and long-term cognitive decline, raising the need for a broad screening to identify individuals at risk for POCD during the perioperative period. In this narrative review, we summarize preoperative, intraoperative and postoperative risk factors for POCD reported in last 5 years and discuss neuropsychological tools and potential biomarkers and time points for assessment that might be suitable for clinical use. We aim to provide crucial information for developing a strategy of routine screening for POCD, which may assist with better identification of at-risk individuals for early interventions. Very importantly, the utilization of a standardized strategy may also allow higher consistency and comparability across different studies.

Geriatric assessment and medical preoperative screening (GrAMPS) program for older hernia patients

PURPOSE

The incidence of older adults undergoing inguinal and ventral hernia repairs is increasing. Older adults are disproportionately affected by age-related risk factors, which are often under-recognized and may adversely affect surgical outcomes. These age-related risk factors often termed "geriatric syndromes," include multimorbidity, frailty, cognitive impairment, depression, obesity, functional impairment, polypharmacy, and poor subjective health. The aim of this study was to identify the prevalence of age-related risk factors in older patients undergoing elective hernia repair.

METHODS

Patients aged 60 years or older with a planned elective surgical repair of a ventral or inguinal hernia were prospectively enrolled in a clinic. Subjects completed several validated screening tools for geriatric syndromes.

RESULTS

Seventy patients completed preoperative assessments (mean age: 68.5 years). In total, 24 (34.3%) screened positive for previously unrecognized objective cognitive impairment (Mini-Cog) and 33 (47.1%) for a subjective memory concern. Sixty patients (85.7%) met criteria for polypharmacy. Additionally, 48 (68.6%) screened positive for either pre-frailty (37, 52.9%) or frailty (11, 15.7%), and 66 (94.3%) had multimorbidity. Twenty-five (35.7%) patients self-rated their health as "poor" or "fair," and 18 (25.7%) patients endorsed some functional impairment.

CONCLUSIONS

There is a high prevalence of age-related risk factors in older patients undergoing elective hernia repair. Further, these factors are often unrecognized and underappreciated despite their potential to significantly impact informed consent and shared decision making. Additional study is required to define the impact of these age-related risk factors on surgical outcomes, which will inform preoperative risk assessment and optimization through modifiable risk reduction.

Postoperative outcomes in older surgical patients with preoperative cognitive impairment: A systematic review and meta-analysis

STUDY OBJECTIVE

To determine the effect of cognitive impairment (CI) and dementia on adverse outcomes in older surgical patients.

DESIGN

A systematic review and meta-analysis of observational studies and randomized controlled trials (RCTs). Various databases were searched from their inception dates to March 8, 2021.

SETTING

Preoperative assessment.

PATIENTS

Older patients (≥ 60 years) undergoing non-cardiac surgery.

MEASUREMENTS

Outcomes included postoperative delirium, mortality, discharge to assisted care, 30-day readmissions, postoperative complications, and length of hospital stay. Effect sizes were calculated as Odds Ratio (OR) and Mean Difference (MD) based on random effect model analysis. The quality of included studies was assessed using the Cochrane Risk Bias Tool for RCTs and Newcastle-Ottawa Scale for observational cohort studies.

RESULTS

Fifty-three studies (196,491 patients) were included. Preoperative CI was associated with a significant risk of delirium in older patients after non-cardiac surgery (25.1% vs. 10.3%; OR: 3.84; 95%CI: 2.35, 6.26; I²: 76%; p < 0.00001). Cognitive impairment (26.2% vs. 13.2%; OR: 2.28; 95%CI: 1.39, 3.74; I²: 73%; p = 0.001) and dementia (41.6% vs. 25.5%; OR: 1.96; 95%CI: 1.34, 2.88; I²: 99%; p = 0.0006) significantly increased risk for 1-year mortality. In patients with CI, there was an increased risk of discharge to assisted care (44.7% vs. 38.3%; OR 1.74; 95%CI: 1.05, 2.89, p = 0.03), 30-day readmissions (14.3% vs. 10.8%; OR: 1.36; 95%CI: 1.00, 1.84, p = 0.05), and postoperative complications (40.7% vs. 18.8%; OR: 1.85; 95%CI: 1.37, 2.49; p < 0.0001).

CONCLUSIONS

Preoperative CI in older surgical patients significantly increases risk of delirium, 1-year mortality, discharge to assisted care, 30-day readmission, and postoperative complications. Dementia increases the risk of 1-year mortality. Cognitive screening in the preoperative assessment for older surgical patients may be helpful for risk stratification so that appropriate management can be implemented to mitigate adverse postoperative outcomes.

Delirium in Older Adults: What a Surgeon Needs to Know

Delirium remains a challenging clinical problem in hospitalized older adults, especially for postoperative patients. This complication, with a high risk of postoperative mortality and an increased length of stay, frequently occurs in older adult patients. This brief narrative paper aims to review the recent literature regarding delirium and its most recent update. We also offer physicians a brief and essential clinical practice guide to managing this acute and common disease.

Does Preoperative Cognitive Optimization Improve Postoperative Outcomes in the Elderly?

Perioperative neurocognitive disorder (PND) is a growing concern, affecting several million elderly patients each year in the United States, but strategies for its effective prevention have not yet been established. Humeidan et al. recently demonstrated that preoperative brain exercise resulted in a decrease in postoperative delirium incidence in elderly surgical patients, suggesting the potential of presurgical cognitive optimization to improve postoperative cognitive outcomes. This brief review summarizes the current knowledge regarding preoperative cognitive optimization and highlights landmark studies, as well as current ongoing studies, as the field is rapidly growing. This review further discusses the benefit of cognitive training in non-surgical elderly populations and the role of cognitive training in patients with preexisting cognitive impairment or dementia. The review also examines preclinical evidence in support of cognitive training, which can facilitate understanding of brain plasticity and the pathophysiology of PND. The literature suggests positive impacts of presurgical cognitive optimization, but further studies are encouraged to establish effective cognitive training programs for elderly presurgical patients.

Prevalence of preoperative cognitive impairment in older surgical patients.: A systematic review and meta-analysis

STUDY OBJECTIVE

Older surgical patients with cognitive impairment are at an increased risk for adverse perioperative outcomes, however the prevalence of preoperative cognitive impairment is not well-established within this population. The purpose of this review is to determine the pooled prevalence of preoperative cognitive impairment in older surgical patients.

DESIGN

Systematic review and meta-analysis.

SETTING

MEDLINE (Ovid), PubMed (non-MEDLINE records only), Embase, Cochrane Central, Cochrane Database of Systematic Reviews, PsycINFO, and EMCare Nursing for relevant articles from 1946 to April 2021.

PATIENTS

Patients aged ≥60 years old undergoing surgery, and preoperative cognitive impairment assessed by validated cognitive assessment tools.

INTERVENTIONS

Preoperative assessment.

MEASUREMENTS

Primary outcomes were the pooled prevalence of preoperative cognitive impairment in older patients undergoing either elective (cardiac or non-cardiac) or emergency surgery.

MAIN RESULTS

Forty-eight studies (n = 42,498) were included. In elective non-cardiac surgeries, the pooled prevalence of unrecognized cognitive impairment was 37.0% (95% confidence interval [CI]: 30.0%, 45.0%) among 27,845 patients and diagnosed cognitive impairment was 18.0% (95% CI: 9.0%, 33.0%) among 11,676 patients. Within the elective non-cardiac surgery category, elective orthopedic surgery was analyzed. In this subcategory, the pooled prevalence of unrecognized cognitive impairment was 37.0% (95% CI: 26.0%, 49.0%) among 1117 patients, and diagnosed cognitive impairment was 17.0% (95% CI: 3.0%, 60.0%) among 6871 patients. In cardiac surgeries, the unrecognized cognitive impairment prevalence across 588 patients was 26.0% (95% CI: 15.0%, 42.0%). In emergency surgeries, the unrecognized cognitive impairment prevalence was 50.0% (95% CI: 35.0%, 65.0%) among 2389 patients.

CONCLUSIONS

A substantial number of surgical patients had unrecognized cognitive impairment. In elective non-cardiac and emergency surgeries, the pooled prevalence of unrecognized cognitive impairment was 37.0% and 50.0%. Preoperative cognitive screening warrants more attention for risk assessment and stratification.

Atorvastatin attenuates surgery-induced BBB disruption and cognitive impairment partly by suppressing NF-κB pathway and NLRP3 inflammasome activation in aged mice

In clinic, perioperative neurocognitive disorder is becoming a common complication of surgery in old patients. Neuroinflammation and blood-brain barrier (BBB) disruption are important contributors for cognitive impairment. Atorvastatin, as a strong HMG-CoA reductase inhibitor, has been widely used in clinic. However, it remains unclear whether atorvastatin could prevent anesthesia and surgery-induced BBB disruption and cognitive injury by its anti-inflammatory property. In this study, aged C57BL/6J mice were used to address this question. Initially, the mice were subject to atorvastatin treatment for 7 days (10 mg/kg). After a simple laparotomy under 1.5% isoflurane anesthesia, Morris water maze was performed to assess spatial learning and memory. Western blot analysis, immunohistochemistry, and enzyme-linked immunosorbent assay were used to examine the inflammatory response, BBB integrity, and cell apoptosis. Terminal-deoxynucleotidyl transferase mediated nick end labeling assay was used to assess cell apoptosis. The fluorescein sodium and transmission electron microscopy were used to detect the permeability and structure of BBB. The results showed that anesthesia and surgery significantly injured hippocampal-dependent learning and memory, which was ameliorated by atorvastatin. Atorvastatin could also reverse the surgery-induced increase of systemic and hippocampal cytokines, including IL-1β, TNF-α, and IL-6, accompanied by inhibiting the nuclear factor kappa-B (NF-κB) pathway and Nucleotide-Binding Oligomerization Domain, or Leucine Rich Repeat and Pyrin Domain Containing 3 (NLRP3) inflammasome activation, as well as hippocampal neuronal apoptosis. In addition, surgery triggered an increase of BBB permeability, paralleled by a decrease of the ZO-1, occludin, and Claudin 5 proteins in the hippocampus. However, atorvastatin treatment could protect the BBB integrity from the impact of surgery, by up-regulating the expressions of ZO-1, occludin, and Claudin 5. These findings suggest that atorvastatin exhibits neuroprotective effects on cognition in aged mice undergoing surgery.

Neuroanesthesiology Update

This review summarizes the literature published in 2020 that is relevant to the perioperative care of neurosurgical patients and patients with neurological diseases as well as critically ill patients with neurological diseases. Broad topics include general perioperative neuroscientific considerations, stroke, traumatic brain injury, monitoring, anesthetic neurotoxicity, and perioperative disorders of cognitive function.

Preexisting Dementia Is Associated with Increased Risks of Mortality and Morbidity Following Major Surgery: A Nationwide Propensity Score Matching Study

Patients with dementia are predisposed to multiple physiological abnormalities. It is uncertain if dementia associates with higher rates of perioperative mortality and morbidity. We used reimbursement claims data of Taiwan’s National Health Insurance and conducted propensity score matching analyses to evaluate the risk of mortality and major complications in patients with or without dementia undergoing major surgery between 2004 and 2013. We applied multivariable logistic regressions to calculate adjusted odds ratios (aORs) with 95% confidence intervals (CIs) for the outcome of interest. After matching to demographic and clinical covariates, 7863 matched pairs were selected for analysis. Dementia was significantly associated with greater risks of 30-day in-hospital mortality (aOR: 1.71, 95% CI: 1.09–2.70), pneumonia (aOR: 1.48, 95% CI: 1.16–1.88), urinary tract infection (aOR: 1.59, 95% CI: 1.30–1.96), and sepsis (OR: 1.77, 95% CI: 1.34–2.34) compared to non-dementia controls. The mortality risk in dementia patients was attenuated but persisted over time, 180 days (aOR: 1.49, 95% CI: 1.23–1.81) and 365 days (aOR: 1.52, 95% CI: 1.30–1.78) after surgery. Additionally, patients with dementia were more likely to receive blood transfusion (aOR: 1.32, 95% CI: 1.11–1.58) and to need intensive care (aOR: 1.40, 95% CI: 1.12–1.76) compared to non-dementia controls. Senile dementia and Alzheimer’s disease were independently associated with higher rates of perioperative mortality and complications, but vascular dementia was not affected. We found that preexisting dementia was associated with mortality and morbidity after major surgery.