Obesity and post-operative cognitive dysfunction: a systematic review and meta-analysis

Impact of butorphanol versus sufentanil on postoperative cognition and inflammation in elderly: a pilot study

Background

This randomized controlled trial aimed to compare the effects of butorphanol and sufentanil on early post-operative cognitive dysfunction (POCD) and systemic inflammation in older surgical patients.

Methods

Patients (aged 65 years or above) undergoing surgeries with general anesthesia were randomized to either the butorphanol group (40 μg/kg during anesthesia induction) or the sufentanil group (0.4 μg/kg). Cognitive function changes during the perioperative period were assessed using the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) scale up to 3 days after surgery. POCD was defined as a Z-score or composite Z-score greater than 1.96 for both MMSE and MoCA scores. Circulating inflammatory factors, including tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL-1β), and interleukin 10 (IL-10), were measured using enzyme-linked immunosorbent assay.

Results

The study included 114 patients (median age: 71 years, 57.7% male). Compared to sufentanil, butorphanol significantly reduced the incidence of POCD on the first (11.5% versus 32.7%, p = 0.017) and third day (3.8% versus 15.4%, p = 0.046) after surgery. Additionally, patients receiving butorphanol had significantly lower circulating levels of TNF-α and IL-1β at the time of discharge from the post-anesthesia care unit and on the first and third day after surgery (p < 0.05 for all comparisons). Furthermore, circulating IL-10 levels were significantly higher in patients receiving butorphanol (p < 0.05 for all comparisons).

Conclusion

Administration of butorphanol during anesthesia induction, as opposed to sufentanil, was associated with a significant reduction in the early incidence of POCD in older surgical patients, possibly attributed to its impact on systemic inflammation.Clinical trial registration: The present study was registered in the China Clinical Trial Center (ChiCTR2300070805, 24/04/2023).

The Association of Plasma Leptin, Soluble Leptin Receptor and Total and High-Molecular Weight Adiponectin With the Risk of Perioperative Neurocognitive Disorders

BACKGROUND

Perioperative neurocognitive disorders (NCD) are poorly characterized in terms of their risk factor profiles. Leptin and adiponectin are adipose-tissue-derived hormones with a role in inflammation and atherosclerosis whose function in perioperative NCD is unclear. Here, we used a cohort of older adults to examine the association of preoperative plasma concentrations of these biomarkers with the risk of perioperative NCD.

METHODS

Prospective analysis of 768 participants aged ≥ 65 years of the BioCog study. Blood was collected before surgery for measurement of plasma total and high-molecular-weight (hmw) adiponectin, leptin, and soluble leptin receptor (sOB-R). The free leptin index (FLI, leptin:sOB-R) was calculated. Postoperative delirium (POD) was assessed twice daily until postoperative day 7/discharge. Five hundred twenty-six patients (68.5%) returned for 3-month follow-up and provided data on postoperative cognitive dysfunction (POCD). POCD was defined as a decline on six neuropsychological tests that exceeded that of a nonsurgical control group. Logistic regression analyses examined the associations of each exposure with POD and POCD risk, in separate models adjusted for age, sex, fasting, surgery type, and body mass index (BMI).

RESULTS

Of 768 patients, 152 (19.8%) developed POD. Of 526 attendants of the follow-up, 54 (10.3%) had developed POCD. Leptin, sOB-R, and total and hmw adiponectin were each not associated with POD. For POCD, we observed reduced risk in patients in FLI quartile 4 compared with quartile 1 (odds ratio, 0.26; 95% CI 0.08, 0.89). Sensitivity analyses for the outcome POD revealed statistically significant interaction terms of sOB-R and total adiponectin with obesity (BMI≥30kg/m2 versus BMI<30kg/m2). For the outcome POCD, a higher sOB-R was associated with an increased risk in the obese subgroup (odds ratio, 4.00; 95% CI 1.01, 15.86).

CONCLUSIONS

We did not find consistent evidence for the role of leptin, its receptor, and total and hmw adiponectin in POD and POCD risk. Future research should be used to support or refute our findings and to fully characterize any differences in the associations of these hormones with POD/POCD between obese and nonobese individuals.

Post-operative cognitive dysfunction is exacerbated by high-fat diet via TLR4 and prevented by dietary DHA supplementation

Post-operative cognitive dysfunction (POCD) is an abrupt decline in neurocognitive function arising shortly after surgery and persisting for weeks to months, increasing the risk of dementia diagnosis. Advanced age, obesity, and comorbidities linked to high-fat diet (HFD) consumption such as diabetes and hypertension have been identified as risk factors for POCD, although underlying mechanisms remain unclear. We have previously shown that surgery alone, or 3-days of HFD can each evoke sufficient neuroinflammation to cause memory deficits in aged, but not young rats. The aim of the present study was to determine if HFD consumption before surgery would potentiate and prolong the subsequent neuroinflammatory response and memory deficits, and if so, to determine the extent to which these effects depend on activation of the innate immune receptor TLR4, which both insults are known to stimulate. Young-adult (3mo) & aged (24mo) male F344xBN F1 rats were fed standard chow or HFD for 3-days immediately before sham surgery or laparotomy. In aged rats, the combination of HFD and surgery caused persistent deficits in contextual memory and cued-fear memory, though it was determined that HFD alone was sufficient to cause the long-lasting cued-fear memory deficits. In young adult rats, HFD + surgery caused only cued-fear memory deficits. Elevated proinflammatory gene expression in the hippocampus of both young and aged rats that received HFD + surgery persisted for at least 3-weeks after surgery. In a separate experiment, rats were administered the TLR4-specific antagonist, LPS-RS, immediately before HFD onset, which ameliorated the HFD + surgery-associated neuroinflammation and memory deficits. Similarly, dietary DHA supplementation for 4 weeks prior to HFD onset blunted the neuroinflammatory response to surgery and prevented development of persistent memory deficits. These results suggest that HFD 1) increases risk of persistent POCD-associated memory impairments following surgery in male rats in 2) a TLR4-dependent manner, which 3) can be targeted by DHA supplementation to mitigate development of persistent POCD.

Protective effect of intranasal insulin on postoperative cognitive dysfunction in elderly patients with metabolic syndrome undergoing noncardiac surgery: a randomized clinical trial

BACKGROUND

Insulin plays a crucial and multifactorial role in cognitive activity, with insulin resistance appearing in neurodegenerative and metabolic diseases. Insulin resistance contributes to the pathobiology of postoperative cognitive dysfunction (POCD) in experimental models, which can be rescued by intranasal insulin administration.

AIMS

To test the effect of intranasal insulin on the incidence of POCD in elderly patients with metabolic syndrome.

METHODS

The study was designed as a randomized, double-blind, placebo-controlled clinical trial. 116 elderly participants were randomly assigned to receive either 40 IU insulin (n = 58) or placebo (n = 58) for 7 days. The primary outcome was the incidence of POCD at 7 days and 3 months after surgery. Secondary outcomes included the degree of peripheral insulin resistance postoperatively, changes in peripheral inflammation levels and the safety of interventions.

RESULTS

The results showed that POCD occurred in the insulin group on the 7th postoperative day in 11 (20.8%) patients, which was fewer than the 23 (45.1%) patients in the placebo group (P = 0.008). The insulin group indicated better cognitive functional performance on language and memory test than the placebo group (P < 0.05). Mean peripheral plasma concentration of TNF-α (P < 0.05) and CRP (P < 0.001) in the insulin group was significantly declined compared with the placebo group on D3 and D7.

CONCLUSIONS

Intranasal insulin administration reduced the incidence of POCD and alleviated peripheral inflammatory levels in elderly patients with metabolic syndrome.

TRIAL REGISTRY

Chinese Clinical Trial Registry (ChiCTR1800015502).

Effects of bariatric surgery on cognitive function in older adults: a prospective longitudinal study

BACKGROUND

Obesity is now well-recognized as an independent risk factor for cognitive decline. Although extensive research has been conducted on cognitive outcomes following bariatric surgery in young adults, very little is known about the impact of advanced age on the cognitive benefits of weight-loss procedures.

OBJECTIVES

This study aimed to assess cognitive function in older Iranian patients before and after bariatric surgery.

SETTING

University Hospital METHODS: In this prospective longitudinal study, 24 older adults were examined before and 4 months after bariatric surgery using the Digit Span Test (DGS), the computerized version of the Wisconsin Card Sorting Test-64 (WCST-64), and the paper-and-pencil versions of the Trail Making Test (TMT), parts A and B, spanning the 4 cognitive domains of attention, working memory, processing speed, and executive functioning. The bariatric surgery group was simultaneously compared to a waiting list control group.

RESULTS

At 4 months of follow-up, comparisons between the groups revealed that the surgical group performed significantly better than the control group on the forward DGS, WCST, and TMT parts A and B. In contrast, there was no significant difference between groups on the backward DGS. Further within-group comparisons demonstrated significant improvements from baseline in forward DGS, WCST, and TMT components A and B. Nevertheless, the same variables did not alter significantly over time in the control group.

CONCLUSIONS

The study suggests measurable cognitive benefits following bariatric surgery in older adults.

Effects of perioperative cognitive function training on postoperative cognitive dysfunction and postoperative delirium: a systematic review and meta-analysis

Background

Randomized controlled trials (RCTs) have shown conflicting results regarding the effects of perioperative cognitive training (CT) on the incidence of postoperative cognitive dysfunction (POCD) and postoperative delirium (POD). We, therefore, performed a meta-analysis to assess the overall effects of studies on this topic.

Methods

We searched PubMed, Embase, the Cochrane Library, and Web of Science for all RCTs and cohort studies that investigated the effects of perioperative CT on the incidence of POCD and POD. Data extraction and quality assessment were conducted independently by two researchers.

Results

This study included nine clinical trials with a total of 975 patients. The results showed that perioperative CT significantly reduced the incidence of POCD compared with the control group [risk ratio (RR) = 0.5, 95% CI (confidence interval): 0.28-0.89, P = 0.02]. Nevertheless, for the incidence of POD, the difference between the two groups was not statistically significant (RR = 0.64; 95% CI: 0.29-1.43, P = 0.28). In addition, the CT group had less postoperative decline in the cognitive function scores compared with the control group [mean differences (MD): 1.58, 95% CI: 0.57-2.59, P = 0.002]. In addition, there were no statistically differences in length of hospital stay between the two groups (MD: -0.18, 95% CI: -0.93-0.57, P = 0.64). Regarding CT adherence, the proportion of patients in the cognitive training group who completed the planned duration of CT was 10% (95% CI: 0.05-0.14, P = 0.258).

Conclusion

Our meta-analysis revealed that perioperative cognitive training is possibly an effective measure to reduce the incidence of POCD, but not for the incidence of POD.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022371306, identifier: CRD42022371306.

Metabolic syndrome and the risk of postoperative delirium and postoperative cognitive dysfunction: a multi-centre cohort study

BACKGROUND

Metabolic syndrome and its components are risk factors for cognitive impairment, but their contribution to perioperative neurocognitive disorders is unknown. We examined their associations with the risk of postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) in older patients.

METHODS

In 765 male and female participants aged ≥65 years, we measured preoperative metabolic parameters and screened for POD for 7 days or until discharge. POCD was defined through comparison of cognitive change on six neuropsychological tests with non-surgical controls. Multiple logistic regression analyses examined the association of metabolic parameters with risk of POD and POCD with adjustment for age, sex, and surgery type.

RESULTS

A total of 149 patients (19.5% of 765) developed POD and 53 (10.1% of 520 attendees) had POCD at 3 months. Patients with metabolic syndrome were at 1.85-fold higher risk of POD (95% confidence interval [CI] 1.26-2.70). Each 1 mmol L^-1 higher high-density lipoprotein cholesterol (HDL-C) was associated with a 0.47-fold lower POD risk (95% CI 0.30-0.74). Each 1 kg m^-2 higher body mass index (BMI) was associated with a 1.09-fold higher POCD risk (95% CI 1.02- 1.16).

CONCLUSIONS

Older surgical patients with metabolic syndrome were at increased risk of POD. Only reduced HDL-C was significantly associated with POD. For POCD, a higher preoperative BMI was identified as a risk factor. These findings add to mounting evidence of a distinct epidemiology of POD and POCD. Screening programmes taking advantage of HDL-C and BMI measurements and of metabolic interventions in reducing perioperative neurocognitive disorders should be evaluated.

CLINICAL TRIAL REGISTRATION

NCT02265263.

Early prediction of delirium upon intensive care unit admission: Model development, validation, and deployment

STUDY OBJECTIVE

To develop, validate, and deploy models for predicting delirium in critically ill adult patients as early as upon intensive care unit (ICU) admission.

DESIGN

Retrospective cohort study.

SETTING

Single university teaching hospital in Taipei, Taiwan.

PATIENTS

6238 critically ill patients from August 2020 to August 2021.

MEASUREMENTS

Data were extracted, pre-processed, and split into training and testing datasets based on the time period. Eligible variables included demographic characteristics, Glasgow Coma Scale, vital signs parameters, treatments, and laboratory data. The predicted outcome was delirium, defined as any positive result (a score ≥ 4) of the Intensive Care Delirium Screening Checklist that was assessed by primary care nurses in each 8-h shift within 48 h after ICU admission. We trained models to predict delirium upon ICU admission (ADM) and at 24 h (24H) after ICU admission by using logistic regression (LR), gradient boosted trees (GBT), and deep learning (DL) algorithms and compared the models' performance.

MAIN RESULTS

Eight features were extracted from the eligible features to train the ADM models, including age, body mass index, medical history of dementia, postoperative intensive monitoring, elective surgery, pre-ICU hospital stays, and GCS score and initial respiratory rate upon ICU admission. In the ADM testing dataset, the incidence of ICU delirium occurred within 24 h and 48 h was 32.9% and 36.2%, respectively. The area under the receiver operating characteristic curve (AUROC) (0.858, 95% CI 0.835-0.879) and area under the precision-recall curve (AUPRC) (0.814, 95% CI 0.780-0.844) for the ADM GBT model were the highest. The Brier scores of the ADM LR, GBT, and DL models were 0.149, 0.140, and 0.145, respectively. The AUROC (0.931, 95% CI 0.911-0.949) was the highest for the 24H DL model and the AUPRC (0.842, 95% CI 0.792-0.886) was the highest for the 24H LR model.

CONCLUSION

Our early prediction models based on data obtained upon ICU admission could achieve good performance in predicting delirium occurred within 48 h after ICU admission. Our 24-h models can improve delirium prediction for patients discharged >1 day after ICU admission.

Peri-Operative Risk Factors Associated with Post-Operative Cognitive Dysfunction (POCD): An Umbrella Review of Meta-Analyses of Observational Studies

This umbrella review aimed to systematically identify the peri-operative risk factors associated with post-operative cognitive dysfunction (POCD) using meta-analyses of observational studies. To date, no review has synthesised nor assessed the strength of the available evidence examining risk factors for POCD. Database searches from journal inception to December 2022 consisted of systematic reviews with meta-analyses that included observational studies examining pre-, intra- and post-operative risk factors for POCD. A total of 330 papers were initially screened. Eleven meta-analyses were included in this umbrella review, which consisted of 73 risk factors in a total population of 67,622 participants. Most pertained to pre-operative risk factors (74%) that were predominantly examined using prospective designs and in cardiac-related surgeries (71%). Overall, 31 of the 73 factors (42%) were associated with a higher risk of POCD. However, there was no convincing (class I) or highly suggestive (class II) evidence for associations between risk factors and POCD, and suggestive evidence (class III) was limited to two risk factors (pre-operative age and pre-operative diabetes). Given that the overall strength of the evidence is limited, further large-scale studies that examine risk factors across various surgery types are recommended.

Age-Related Perioperative Neurocognitive Disorders: Experimental Models and Druggable Targets

With the worldwide increase in life span, surgical patients are becoming older and have a greater propensity for postoperative cognitive impairment, either new onset or through deterioration of an existing condition; in both conditions, knowledge of the patient's preoperative cognitive function and postoperative cognitive trajectory is imperative. We describe the clinical utility of a tablet-based technique for rapid assessment of the memory and attentiveness domains required for executive function. The pathogenic mechanisms for perioperative neurocognitive disorders have been investigated in animal models in which excessive and/or prolonged postoperative neuroinflammation has emerged as a likely contender. The cellular and molecular species involved in postoperative neuroinflammation are the putative targets for future therapeutic interventions that are efficacious and do not interfere with the surgical patient's healing process.

Difference in GFAP Levels in POCD and Non-POCD Patients After on Pump CABG

Introduction

On-pump, coronary artery bypass grafting (CABG) is the most common cause of postoperative cognitive dysfunction (POCD) after cardiac surgery. Previous studies showed that the incidence of POCD after cardiac surgery was 60%, higher than non-cardiac surgery with 11.7%. Glial fibrillary acid protein (GFAP) is one of the sensitive biomarkers of brain damage. Previous studies have found that elevated GFAP serum is associated with cognitive impairment. This study aims to measure the difference in GFAP levels in POCD and non-POCD patients after CABG on-pump surgery.

Methods

This study is a retrospective cohort design study. The data were obtained from 56 subjects undergoing elective CABG on the pump surgery enrolled into two groups consisting of 28 POCD as a case group and 28 non-POCD as a control group. In this study, the ELISA method measured the levels of GFAP biomarkers within 24 hours after surgery. After 72 hours, the patient received a MoCA-INA examination to determine cognitive impairment. Data analysis was carried out by SPSS 23.00 software.

Results

The mean age of patients in both groups was 60 years and was dominated by males (>85%). POCD patients were found to have a significantly longer duration of cardiopulmonary bypass (CPB) and cross-clamp surgery than non-POCD patients (p = 0.002 and p = 0.004). Postoperative GFAP levels in POCD patients were significantly higher than in non-POCD patients (12.95 ± 7.47 vs 3.80 ± 2.77, p < 0.001). There was a significant increase in GFAP levels compared with non-POCD (8.28 ± 7.24 vs -1.5 ± 3.03, p < 0.001). The area under the curve (AUC) value of GFAP against POCD was 0.887, cut-off GFAP 4.750 with a sensitivity of 92.9% and a specificity of 71.4%.

Conclusion

POCD patients had higher GFAP levels than non-POCD patients. There are differences in GFAP levels in patients with POCD and non-POCD post-CABG surgery.

Nomogram to predict postoperative cognitive dysfunction in elderly patients undergoing gastrointestinal tumor resection

OBJECTIVE

To establish a nomogram model for the prediction of postoperative cognitive dysfunction (POCD) in elderly patients undergoing gastrointestinal tumor resection.

METHODS

A total of 369 elderly patients scheduled for elective gastrointestinal tumor resection under general anesthesia were included. The cognitive function of each participant was assessed by the Mini-Mental State Examination (MMSE) 1 day before surgery and 7 days after surgery for the diagnosis of POCD. According to the results, patients were divided into a POCD group and a non-POCD group. The differences in hospitalization data and examination results between the two groups were compared. A logistic regression model was used to explore the risk factors for POCD in elderly patients undergoing gastrointestinal tumor resection, and a nomogram was then constructed based on these factors. The diagnostic performance of the nomogram was evaluated using the area under the receiver operating characteristic curve (AUROC) and a calibration plot. The clinical usefulness of the nomogram was estimated using decision curve analysis (DCA).

RESULTS

Among the 369 patients undergoing gastrointestinal tumor resection, 79 patients had POCD, with a positive rate of 21.4%. The nomogram model comprised the following variables: age, body mass index (BMI), history of cerebrovascular disease, preoperative white blood cell (WBC) count, preoperative hemoglobin (Hb) level, intra-operative blood loss, and operation time. The model showed good discrimination, with an area under the curve (AUC) of 0.710 (95% CI = 0.645-0.775), and good calibration (Hosmer-Lemeshow test, χ2 = 5.133, p = 0.274). Internal validation also maintained ideal discrimination and calibration. Decision curves indicated that when the threshold probability was above 0.1, the nomogram achieved more benefit than both the treat-all and treat-none policies.

CONCLUSION

This scoring system is the first nomogram model developed for the prediction of POCD in elderly patients undergoing gastrointestinal tumor resection. It has good efficacy in the prediction of POCD risk and could provide an important reference for the prevention, management, and treatment of POCD.

Prehabilitative resistance exercise reduces neuroinflammation and improves mitochondrial health in aged mice with perioperative neurocognitive disorders

Background

Postoperative neurocognitive dysfunction remains a significant problem in vulnerable groups such as the elderly. While experimental data regarding its possible pathogenic mechanisms accumulate, therapeutic options for this disorder are limited. In this study, we evaluated the neuroprotective effect of a period of preconditioning resistant training on aged mice undergoing abdominal surgery. Further, we examined the underlying mechanisms from the perspective of neuroinflammatory state and synaptic plasticity in the hippocampus.

Methods

18-month-old C57BL/6N mice were trained for 5 weeks using a ladder-climbing protocol with progressively increasing weight loading. Preoperative baseline body parameters, cognitive performance and neuroinflammatory states were assessed and compared between sedentary and trained groups of 9-month-old and 18-month-old mice. To access the neuroprotective effect of resistance training on postoperative aged mice, both sedentary and trained mice were subjected to a laparotomy under 3% sevoflurane anesthesia. Cognitive performance on postoperative day 14, hippocampal neuroinflammation, mitochondrial dysfunction and synaptic plasticity were examined and compared during groups.

Results

18-month-old mice have increased body weight, higher peripheral and central inflammatory status, reduction in muscle strength and cognitive performance compared with middle-aged 9-month-old mice, which were improved by resistance exercise. In the laparotomy group, prehabilitative resistant exercise improved cognitive performance and synaptic plasticity, reduced inflammatory factors and glial cells activation after surgery. Furthermore, resistance exercise activated hippocampal PGC-1α/BDNF/Akt/GSK-3β signaling and improved mitochondrial biogenesis, as well as ameliorated mitochondrial dynamics in postoperative-aged mice.

Conclusions

Resistance exercise reduced risk factors for perioperative neurocognitive disorders such as increased body weight, elevated inflammatory markers, and pre-existing cognitive impairment. Accordantly, preoperative resistance exercise improved surgery-induced adverse effects including cognitive impairment, synaptic deficit and neuroinflammation, possibly by facilitate mitochondrial health through the PGC1-a/BDNF pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02483-1.

Meta-Analysis of the Correlation between Postoperative Cognitive Dysfunction and Intraoperative Cerebral Oxygen Saturation

Objective

This study is aimed at performing a meta-analysis for discussing the association between postoperative cognitive dysfunction (POCD) and cerebral cortical oxygen saturation after surgery (rSO2).

Method

Search common English databases such as Cochrane Library, PubMed, and Embase databases to evaluate the quality of all references. According to the normalized mean difference (SMD) and 95% confidence interval calculated by the revman5 software, the correlation between reported POCD and rSO2 was evaluated. The retrieval time is up to February 1, 2021.

Results

A total of 7 randomized controlled trials and 564 POCD patients were included in the study, with follow-up duration of 1-12 months. All patients were divided into control and operation subgroups. In the subgroup analysis of elderly patients, abdominal surgery, and orthopedic surgery, the mean intraoperative cerebral oxygen saturation of patients with POCD was significantly lower than those of patients without POCD (I 2 = 55%, SMD = -0.57).

Conclusion

Lower intraoperativersO2 was associated with reduced incidence of neurological complications and renal alure as well as the length of stay in the intensive care unit and the total hospital stay.

A review on the anesthetic management of obese patients undergoing surgery

There has been an observed increase in theprevalence of obesity over the past few decades. The prevalence of anesthesiology related complications is also observed more frequently in obese patients as compared to patients that are not obese. Due to the increased complications that accompany obesity, obese patients are now more often requiring surgical interventions. Therefore, it is important that anesthesiologists be aware of this development and is equipped to manage these patients effectively and appropriately. As a result, this review highlights the effective management of obese patients undergoing surgery focusing on the preoperative, perioperative and postoperative care of these patients.

Preoperative preparation and premedication of bariatric surgical patient

The prevalence of obesity has tripled worldwide over the past four decades. The United States has the highest rates of obesity, with 88% of the population being overweight and 36% obese. The UK has the sixth highest prevalence of obesity. The problem of obesity is not isolated to the developed world and has increasingly become an issue in the developing world as well. Obesity carries an increased risk of many serious diseases and health conditions, including type 2 diabetes, heart disease, stroke, sleep apnea, and certain cancers. Our ability to take care of this population safely throughout the perioperative period begins with a thorough and in-depth preoperative assessment and meticulous preparation. The preoperative assessment begins with being able to identify patients who suffer from obesity by using diagnostic criteria and, furthermore, being able to identify patients whose obesity is causing pathologic and physiologic changes. A detailed and thorough anesthesia assessment should be performed, and the anesthesia plan individualized and tailored to the specific patient's risk factors and comorbidities. The important components of the preoperative anesthesia assessment and patient preparation in the patient suffering from obesity include history and physical examination, airway assessment, medical comorbidities evaluation, functional status determination, risk assessment, preoperative testing, current weight loss medication, and review of any prior weight loss surgeries and their implications on the upcoming anesthetic. The preoperative evaluation of this population should occur with sufficient time before the planned operation to allow for modifications of the preoperative management without needing to delay surgery as the perioperative management of patients suffering from obesity presents significant practical and organizational challenges.

Construction and Application of a Model for Predicting the Risk of Delirium in Postoperative Patients With Type a Aortic Dissection

Background: Postoperative delirium (POD), an alteration in a patient's consciousness pattern, can affect the treatment and prognosis of a disease.

Objective: To construct a prediction model for delirium in patients with type A aortic dissection after surgery and to validate its effectiveness.

Methods: A retrospective cohort design was used to study 438 patients undergoing surgical treatment for type A aortic dissection from April 2019 to June 2020 in tertiary care hospitals. POD (n = 78) and non-delirium groups (n = 360) were compared and analyzed for each index in the perioperative period. A prediction model was established using multifactorial logistic regression, and 30 patients' perioperative data were collected for model validation.

Results: Eight predictors were included in this study: smoking, diabetes, previous cardiovascular surgery, ejection fraction (EF), time to aortic block, acute kidney injury, low cardiac output syndrome, and pulmonary complications. The area under the receiver operating characteristic (ROC) curve of the constructed prediction model was 0.98 ± 0.005, and the Youden index was 0.91. The validation results showed 97% sensitivity, 100% specificity, and 93% accuracy. The expression of the model was Z = Smoking assignment^* – 2.807 – 6.009^*Diabetes assignment – 2.994^*Previous cardiovascular surgery assignment – 0.129^*Ejection fraction assignment + 0.071^*Brain perfusion time assignment – 2.583^*Acute kidney injury assignment – 2.916^*Low cardiac output syndrome assignment – 3.461^*Pulmonary related complications assignment + 20.576.

Conclusion: The construction of an effective prediction model for the risk of delirium in patients after type A aortic stratification can help identify patients at high risk of POD early. It also provides a reference for healthcare professionals in the prevention and care of these patients.

Long sleep duration is associated with cognitive frailty among older community-dwelling adults: results from West China Health and Aging Trend study

OBJECTIVE

To investigate the association between sleep duration and cognitive frailty among older adults dwelling in western China.

METHODS

We used the baseline data from West China Health and Aging Trend (WCHAT) study. Sleep duration was classified as short sleep duration (< 6 h), normal sleep duration (6-8 h) and long sleep duration (≥ 9 h). Fried frailty criteria and Short Portable Mental Status Questionnaire were used to measure cognitive frailty. Multinomial logistic regression was conducted to estimate odds ratio (OR) and 95% confidence interval (CI).

RESULTS

A total of 4093 older adults (age = 67.8 ± 5.9 years, 1708 males and 2385 females) were included in the analysis. The prevalence of cognitive frailty was 11.8% among older adults in western China. Approximately 11.9% participants had short sleep duration (< 6 h); 22.2% had a long sleep duration (≥ 9 h). After adjusting for covariates, only long sleep duration was significantly associated with high risk of cognitive frailty (OR = 2.07, 95%CI = 1.60-2.68, P <  0.001) in western China older adults compared to normal sleep duration.

CONCLUSIONS

Long sleep duration was significantly related to cognitive frailty in older adults. Intervention for long sleep duration may be helpful to prevent cognitive frailty.

TRIAL REGISTRATION

Chinese Clinical Trial Registry: ChiCTR1800018895 .

High-Mobility Group Box-1 and Its Potential Role in Perioperative Neurocognitive Disorders

Aseptic surgical trauma provokes the release of HMGB1, which engages the innate immune response after binding to pattern-recognition receptors on circulating bone marrow-derived monocytes (BM-DM). The initial systemic inflammation, together with HMGB1, disrupts the blood-brain barrier allowing penetration of CCR2-expressing BM-DMs into the hippocampus, attracted by the chemokine MCP-1 that is upregulated by HMGB1. Within the brain parenchyma quiescent microglia are activated and, together with the translocated BM-DMs, release proinflammatory cytokines that disrupt synaptic plasticity and hence memory formation and retention, resulting in postoperative cognitive decline (PCD). Neutralizing antibodies to HMGB1 prevents the inflammatory response to trauma and PCD.

The risk factors of postoperative delirium in general anesthesia patients with hip fracture: Attention needed

Delirium is a common postoperative complication of patients with hip fracture, yet the risk factors for postoperative delirium in patients with hip fracture remain unclear. We aimed to evaluate the associated risk factors of postoperative delirium in patients with hip fracture, to provide evidence for formulating coping measures of postoperative delirium prevention and treatment in clinical practice.Patients undergoing surgery for hip fracture from March 1, 2018 to September 30, 2020 in our hospital were included. The related characteristics and related lab examination results were reviewed and collected. The univariate and logistic regression analyses were performed to identify the potential risk factors.A total of 462 patients were included, the incidence of postoperative delirium in patients with hip fracture was 16.02%. Logistic regression analyses indicated that history of delirium (OR = 4.38, 1.15-9.53), diabetes mellitus (OR = 5.31, 1.23-10.75), hypoalbuminemia (OR = 4.97, 1.37-9.86), postoperative hypoxemia (OR = 5.67, 2.24-13.42), and body mass index (BMI) (kg/m2) (OR = 3.03, 1.36-6.18) were the independent risk factors for the delirium in patients with hip fracture surgery (all P < 0.05). The cutoff value of postoperative blood sugar, albumin, and BMI for delirium prediction was 8.05 (mmol/L), 32.26 (g/L), and 19.35 (kg/m2), respectively, and the area under curve of postoperative blood sugar, albumin, and BMI was 0.792, 0.714, and 0.703, respectively.Those patients with a history of delirium, postoperative hypoxemia, blood glucose ≥8.05 mmol/L, albumin ≤32.26 g/L, and BMI ≤19.35 kg/m2 particularly need the attention of healthcare providers for the prevention of delirium.

The Impact of Monitoring Depth of Anesthesia and Nociception on Postoperative Cognitive Function in Adult Multiple Trauma Patients

Background and Objectives: Patients with traumatic injuries have often been excluded from studies that have attempted to pinpoint modifiable factors to predict the transient disturbance of the cognitive function in the postoperative settings. Anesthetists must be aware of the high risk of developing postoperative delirium and cognitive dysfunction (POCD) in patients undergoing emergency surgery. Monitoring the depth of anesthesia in order to tailor anesthetic delivery may reduce this risk. The primary aim of this study was to improve the prevention strategies for the immediate POCD by assessing anesthetic depth and nociception during emergency surgery. Material and Methods: Of 107 trauma ASA physical status II-IV patients aged over 18 years undergoing emergency noncardiac surgery, 95 patients were included in a prospective randomized study. Exclusion criteria were neurotrauma, chronic use of psychoactive substances or alcohol, impaired preoperative cognitive function, pre-existing psychopathological symptoms, or expected surgery time less than 2 h. Entropy and Surgical Pleth Index (SPI) values were constantly recorded for one group during anesthesia. POCD was assessed 24 h, 48 h, and 72 h after surgery using the Neelon and Champagne (NEECHAM) Confusion Scale. Results: Although in the intervention group, fewer patients experienced POCD episodes in comparison to the control group, the results were not statistically significant (p < 0.08). The study showed a statistically significant inverse correlation between fentanyl and the NEECHAM Confusion Scale at 24 h (r = -0.32, p = 0.0005) and 48 h (r = -0.46, p = 0.0002), sevoflurane and the NEECHAM Confusion Scale at 24 h (r = -0.38, p = 0.0014) and 48 h (r = -0.52, p = 0.0002), and noradrenaline and POCD events in the first 48 h (r = -0.46, p = 0.0013 for the first 24 h, respectively, and r = -0.46, p = 0.0002 for the next 24 h). Conclusions: Entropy and SPI monitoring during anesthesia may play an important role in diminishing the risk of developing immediate POCD after emergency surgery.

Stability of neuropsychological test performance in older adults serving as normative controls for a study on postoperative cognitive dysfunction

OBJECTIVE

Studies of postoperative cognitive dysfunction (POCD) rely on repeat neuropsychological testing. The stability of the applied instruments, which are affected by natural variability in performance and measurement imprecision, is often unclear. We determined the stability of a neuropsychological test battery using a sample of older adults from the general population. Forty-five participants aged 65 to 89 years performed six computerized and non-computerized neuropsychological tests at baseline and again at 7 day and 3 months follow-up sessions. Mean scores on each test were compared across time points using repeated measures analyses of variance (ANOVA) with pairwise comparison. Two-way mixed effects, absolute agreement analyses of variance intra-class correlation coefficients (ICC) determined test-retest reliability.

RESULTS

All tests had moderate to excellent test-retest reliability during 7-day (ICC range 0.63 to 0.94; all p < 0.01) and 3-month intervals (ICC range 0.60 to 0.92; all p < 0.01) though confidence intervals of ICC estimates were large throughout. Practice effects apparent at 7 days eased off by 3 months. No substantial differences between computerized and non-computerized tests were observed. We conclude that the present six-test neuropsychological test battery is appropriate for use in POCD research though small sample size of our study needs to be recognized as a limitation. Trial registration ClinicalTrials.gov Identifier NCT02265263 (15th October 2014).

Perioperative care of the obese patient

Background

Obesity has become an increasing problem worldwide during the past few decades. Hence, surgeons and anaesthetists will care for an increasing number of obese patients in the foreseeable future, and should be prepared to provide optimal management for these individuals. This review provides an update of recent evidence regarding perioperative strategies for obese patients.

Methods

A search for papers on the perioperative care of obese patients (English language only) was performed in July 2019 using the PubMed, Scopus, Web of Science and Cochrane Library electronic databases. The review focused on the results of RCTs, although observational studies, meta-analyses, reviews, guidelines and other reports discussing the perioperative care of obese patients were also considered. When data from obese patients were not available, relevant data from non-obese populations were used.

Results and conclusion

Obese patients require comprehensive preoperative evaluation. Experienced medical teams, appropriate equipment and monitoring, careful anaesthetic management, and an adequate perioperative ventilation strategy may improve postoperative outcomes. Additional perioperative precautions are necessary in patients with severe morbid obesity, metabolic syndrome, untreated or severe obstructive sleep apnoea syndrome, or obesity hypoventilation syndrome; patients receiving home ventilatory support or postoperative opioid therapy; and obese patients undergoing open operations, long procedures or revisional surgery.

Current Perspectives on Postoperative Cognitive Dysfunction in the Ageing Population

Postoperative cognitive dysfunction (POCD) is defined as a prolonged cognitive function impairment that occurs within weeks to months of a surgical procedure. It is especially prevalent in the elderly population, leading to increased morbidity and mortality. As anaesthetic and surgical care continues to improve and become increasingly safer, a significantly greater number of older patients have elective surgical procedures today, yet this comes with an increased POCD risk as they go through the perioperative phases. Although the pathophysiology behind the development of POCD is still under investigation, current causative mechanisms include the mode of anaesthesia administered, anaesthetic used, cerebral hypoperfusion, hyperventilation and neuroinflammation. These findings lend an insight into the importance of being cognisant of the higher likelihood of POCD in at-risk patients, including the elderly, and taking precautions to include preoperative and postoperative cognitive testing, careful monitoring during anaesthesia, blood pressure control and early treatment of postoperative complications as they arise. In this review, we provide an update on the current understanding of the pathophysiology leading to POCD, identifying risk factors, prevention and treatment strategies, with a specific focus on the elderly population.

Insulin Resistance Predicts Postoperative Cognitive Dysfunction in Elderly Gastrointestinal Patients

Background

Members of the aging population who undergo surgery are at risk of postoperative cognitive dysfunction (POCD). Exploring an effective and reliable early predictor of POCD is essential to the identification of high-risk patients and to making prospective decisions. The purpose of this study was to examine whether preoperative insulin resistance is an independent predictor of POCD.

Methods

A total of 124 patients aged 60 years and older and who were scheduled for gastrointestinal surgery were enrolled in a prospective observational clinical study. All participants completed a battery of neuropsychological tests before surgery and 7 days later. POCD was defined as a decline of at least 1.5 SD on two or more of neuropsychological tests. Plasma concentration of the tumor necrosis factor α (TNF-α), C-reactive protein (CRP), and S-100β protein were measured. The status of insulin resistance was assessed by Homeostasis Model Assessment–Insulin Resistance (HOMA-IR). The relationship between HOMA-IR and POCD was assessed by Multivariable logistic regression models and the receiver operating characteristic (ROC) curve.

Results

Fifty one patients (41.1%) were diagnosed with POCD at 7 days after surgery. Preoperative HOMA-IR values of the POCD group were significantly higher than the non-POCD group. Furthermore, CRP and TNF-α levels of the POCD group were significantly higher at each postoperative time point (P < 0.05). The preoperative HOMA-IR value was an independent predictor of POCD (adjusted OR 1.88, 95% CI, 1.18–2.99) even after adjust for confounding variables, and when dichotomized, individuals above the HOMA-IR threshold (HOMA-IR > 2.6) had a three-times higher risk of POCD (OR 3.26; 95% CI, 1.07–9.91) compared to individuals below the threshold. The areas under the ROC curve of HOMA-IR was 0.804 (95% CI, 0.725–0.883; P < 0.001). The optimal cut-off value was found to be 0.583, with a sensitivity of 84.3% and specificity of 74%. The HOMA-IR value was positively associated with the TNF-α concentration at baseline (R² = 0.43, P < 0.01) and 1 day after surgery (R² = 0.3861, P < 0.01).

Conclusion

Preoperative insulin resistance is an effective predictor for the occurrence of POCD. Targeted prevention and treatment strategies of insulin resistance may be effective interventions of patients at risk for POCD.

Neuropsychological Functioning in Older Adults with Obesity: Implications for Bariatric Surgery

Bariatric surgery is the most effective approach to treating morbid obesity, resulting in decreased morbidity, mortality, and improved quality of life. Research on outcomes has generally been restricted to young and middle-aged adults, despite a growing epidemic of obesity in older adults. The use of bariatric surgery has been limited in older individuals, in part due to concerns that preexisting cognitive dysfunction increases the risk of poor post-surgical outcomes, including cognitive decline. The literature on the relationship between obesity and cognition in older adults is emerging, but fraught by several methodological limitations. While there is insufficient research to determine the nature of cognitive outcomes following bariatric surgery in older adults, the aim of this paper is to review the existing evidence and make the case for further study.

Diabetes, but Not Hypertension and Obesity, Is Associated with Postoperative Cognitive Dysfunction

BACKGROUND/AIMS

Older people undergoing surgery are at risk of developing postoperative cognitive dysfunction (POCD), but little is known of risk factors predisposing patients to POCD. Our objective was to estimate the risk of POCD associated with exposure to preoperative diabetes, hypertension, and obesity.

METHODS

Original data from 3 randomised controlled trials (OCTOPUS, DECS, SuDoCo) were obtained for secondary analysis on diabetes, hypertension, baseline blood pressure, obesity (BMI ≥30 kg/m2), and BMI as risk factors for POCD in multiple logistic regression models. Risk estimates were pooled across the 3 studies.

RESULTS

Analyses totalled 1,034 patients. POCD occurred in 5.2% of patients in DECS, in 9.4% in SuDoCo, and in 32.1% of patients in OCTOPUS. After adjustment for age, sex, surgery type, randomisation, obesity, and hypertension, diabetes was associated with a 1.84-fold increased risk of POCD (OR 1.84; 95% CI 1.14, 2.97; p = 0.01). Obesity, BMI, hypertension, and baseline blood pressure were each not associated with POCD in fully adjusted models (all p > 0.05).

CONCLUSION

Diabetes, but not obesity or hypertension, is associated with increased POCD risk. Consideration of diabetes status may be helpful for risk assessment of surgical patients.

Association Between Insulin Resistance, Plasma Leptin, and Neurocognition in Vascular Cognitive Impairment

BACKGROUND

Greater body weight has been associated impairments in neurocognition and greater dementia risk, although the mechanisms linking weight and neurocognition have yet to be adequately delineated.

OBJECTIVE

To examine metabolic mechanisms underlying the association between obesity and neurocognition.

METHODS

We conducted a secondary analysis of weight, neurocognition, and the potentially mediating role of metabolic and inflammatory biomarkers among 160 participants from the ENLIGHTEN trial of vascular cognitive impairment, no dementia (CIND). Neurocognition was assessed using a 45-minute assessment battery assessing Executive Function, Verbal and Visual Memory. We considered three metabolic biomarkers: insulin resistance (homeostatic model assessment [HOMA-IR]), plasma leptin, and insulin-like growth factor (IGF-1). Inflammation was assessed using C-reactive protein. Multiple regression analyses were used.

RESULTS

Participants included 160 sedentary older adults with CIND. Participants tended to be overweight or obese (mean BMI = 32.5 [SD = 4.8]). Women exhibited higher BMI (p = 0.043), CRP (p < 0.001), and leptin (p < 0.001) compared with men. Higher BMI levels were associated with worse performance on measures of Executive Function (β= -0.16, p = 0.024) and Verbal Memory (β= -0.16, p = 0.030), but not Visual Memory (β= 0.05, p = 0.500). Worse metabolic biomarker profiles also were associated with lower Executive Function (β= -0.12, p = 0.050). Mediation analyses suggested leptin was a plausible candidate as a mediator between BMI and Executive Function.

CONCLUSIONS

In overweight and obese adults with vascular CIND, the association between greater weight and poorer executive function may be mediated by higher leptin resistance.

Sirt1 mediates improvement of isoflurane-induced memory impairment following hyperbaric oxygen preconditioning in middle-aged mice

Hyperbaric oxygen (HBO) preconditioning (PC) has been suggested as a feasible method to provide neuroprotection from postoperative cognitive dysfunction (POCD). However, whether HBO-PC can ameliorate cognitive deficits induced by isoflurane, and the possible mechanism by which it may exert its effect, has not yet been clarified. In the present study, middle-aged mice were exposed to isoflurane anesthesia (1.5 minimal alveolar concentration [MAC]) for 2 h to establish a POCD model. After HBO preconditioning, cognitive function and expression of hippocampal sirtuin 1 (Sirt1), nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) were evaluated 24 h following isoflurane treatment, in the presence or absence of Sirt1 knockdown by short hairpin RNA (shRNA). HBO preconditioning increased the expression of Sirt1, Nrf2, and HO-1 and ameliorated memory dysfunction. Meanwhile, Sirt1 knockdown inhibited the expression of Nrf2 and HO-1 and attenuated the HBO preconditioning-associated memory improvement. Our results suggest that the application of HBO preconditioning is a useful treatment for POCD, and that Sirt1 may be a potential molecular target for POCD therapy.

Impact on the brain of the inflammatory response to surgery

The brain is both the orchestrator as well as the target of the innate immune system's response to the aseptic trauma of surgery. When trauma-induced inflammation is not appropriately regulated persistent neuro-inflammation interferes with the synaptic plasticity that underlies the learning and memory aspects of cognition. The complications that ensue, include postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) at two poles of a constellation that is now termed perioperative neurocognitive disorders. While the relationship of acute POD to the more indolent POCD is not completely understood both can be further complicated by earlier-onset of dementia and higher mortality. How and why these disorders occur is the focus of this report. The innate immune system response to peripheral trauma signals to the brain through a regulated cascade of cellular and molecular actors producing a teleological defense mechanism, "sickness behavior," to curtail further injury and initiate repair. Sickness behavior, including disordered cognition, is terminated by neural and humoral pathways that restore homeostasis and launch the organism on a path to good health. With so many "moving parts" the innate immune system is vulnerable in clinical settings that include advanced age and lifestyle-induced diseases such as "unhealthy" obesity and the inevitable insulin resistance. Under these conditions, inflammation may become exaggerated and long-lived. Consideration is provided how to identify the high-risk surgical patient and both pharmacological (including biological compounds) and non-pharmacological strategies to customize care.

TREK-1 pathway mediates isoflurane-induced memory impairment in middle-aged mice

Post-operative cognitive dysfunction (POCD) has been widely reported, especially in elderly patients. An association between POCD and inhalational anesthetics, such as isoflurane, has been suggested. The TWIK-related K⁺ channel-1 (TREK-1) controls several major cellular responses involved in memory formation and is believed to participate in the development of depression, cerebral ischemia and blood-brain barrier dysfunction. However, the specific role of TREK-1 in mediating anesthesia-induced POCD remains unknown. In the current study, we determined that exposure to isoflurane affected memory in middle-aged mice and altered TREK-1 expression. In addition, TREK-1 over-expression exacerbated isoflurane-induced memory impairment, while TREK-1 silence attenuated the impairment. Taken together, our data demonstrate that inhibition of TREK-1 protects mice from cognitive impairment induced by anesthesia and TREK-1 is a potential therapeutic target against memory impairment induced by volatile anesthetics.

Hypertension and Risk of Post-Operative Cognitive Dysfunction (POCD): A Systematic Review and Meta-Analysis

Background:

Post-operative cognitive dysfunction (POCD) occurs frequently after major surgery. Hypertension is well-established as a risk factor for age-related cognitive impairment, but it is unclear whether or not it also increases the risk of POCD.

Objective:

To evaluate the role of hypertension in POCD risk in a systematic review and meta-analysis.

Method:

PubMed, Ovid SP and the Cochrane Database of Systematic Reviews were searched for longitudinal studies of adults undergoing surgery with reporting of hypertension, blood pressure and/or anti-hypertensive treatment associations with POCD as relative risks or odds ratios. Fixed-effects meta-analyses were performed using Review Manager (version 5.3).

Results:

Twenty-four studies on 4317 patients (mean age 63 years) were included. None of the studies had set out to assess hypertension as a risk factor for POCD. Hypertension was used as a categorical predictor throughout and only 2 studies adjusted for potential confounders. Across all 24 studies, hypertension was not significantly associated with POCD risk (RR 1.01; 95% CI 0.93, 1.09; p=0.82), though among 8 studies with >75% males, we found hypertension associations with a 27% increased risk of POCD (RR 1.27, 95% CI 1.07, 1.49; p=0.005).

Conclusion:

Our findings do not support the hypothesis that hypertension is a risk factor for POCD. However, since none of the studies included in our analysis were hypothesis-driven and most did not adjust for potential confounders, further systematic investigations are needed to evaluate the role of hypertension in the epidemiology of POCD.

Spies C, Pischon T. Cognitive Reserve and the Risk of Postoperative Cognitive Dysfunction

BACKGROUND

Post-operative cognitive dysfunction (POCD) occurs in 10 to 54% of older patients during the first few weeks after surgery, but little is known about risk factors predisposing to POCD.

METHODS

Systematic literature review and meta-analysis of cognitive reserve indicators and POCD risk.

RESULTS

Fifteen studies on 5104 patients were included. Follow-up periods spanned 1 day to 6 months. Educational level was the most commonly assessed cognitive reserve indicator, and a longer time spent in education was associated with a reduced risk of POCD (relative risk [RR] per year increment 0.90; 95% confidence interval: [0.87; 0.94]), i.e. each year increase in education was associated with a 10% reduced risk. Similar findings were made for some analyses on education as a categorical predictor (high school versus further/higher education, RR 1.71, [1.30; 2.25]; lower than high school versus further/higher education, RR 1.69, [1.17; 2.44]) though risk was equivalent for patients with high school education and those with lower than high school education (RR 1.02; [0.78; 1.32]).

CONCLUSION

Patients with a relatively higher level of education are at reduced risk of POCD. Risk stratification of surgical patients according to educational level may prove useful.