Perioperative Brain Health in the Older Adult: A Patient Safety Imperative

Prevalence of postoperative neurocognitive disorders in older non-cardiac surgical patients: A systematic review and meta-analysis

STUDY OBJECTIVE

The growing number of older persons undergoing surgery are at a higher risk of neurocognitive disorder due to multimorbidity and age-related changes. Previous reviews estimated postoperative neurocognitive disorder or cognitive dysfunction (POCD) prevalence without accounting for the sample size or study quality. The prevalence of POCD in this population requires further investigation. This systematic review and meta-analysis applies systematic weighting to estimate the pooled prevalence of POCD in older non-cardiac surgical patients.

DESIGN

Systematic review and meta-analysis.

SETTING

MEDLINE, MEDLINE ePub, Embase, Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews for relevant articles.

PATIENTS

Non-cardiac surgical patients aged ≥60 years old.

INTERVENTIONS

Perioperative cognitive assessments.

MEASUREMENT

The primary outcome was the prevalence of POCD.

MAIN RESULTS

Thirty-nine studies (n = 12,921) were included with mean age of 70.0 ± 8.9 years and 44.3 % women. The overall prevalence of POCD was 23 % (95 % CI: 20 %, 27 %) at day 7, 16 % (95 % CI: 7 %, 25 %) at 1 month, 10 % (95 % CI: 8 %, 13 %) at 3 months and 3 % (95 % CI: 2 %, 4 %) at 1 year. Our meta-regression showed a higher prevalence of POCD in abdominal surgeries at day 7 (β = 0.13, 95 % CI: 0.03-0.22, P = 0.01) and 3 months (β = 0.49, 95 % CI: 0.40-0.58, P < 0.001), versus orthopedic surgeries.

CONCLUSIONS

The overall prevalence of POCD in older non-cardiac surgical populations was 23 %, 16 %, 10 %, and 3 % at day 7, 1 month, 3 months, and 1 year, respectively. Abdominal surgery had a higher prevalence of POCD than orthopedic surgery. The substantial risk of POCD calls for cognitive screening, risk mitigation and interventions to improve surgical outcomes. Through routine preoperative cognitive screening and addressing modifiable risk factors, the incidence and impact of POCD can be markedly reduced, enhancing patient outcomes and recovery.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

SYSTEMATIC REVIEW PROTOCOL

PROSPERO CRD42024520287.

The Role of the Glymphatic System in Perioperative Neurocognitive Disorders

BACKGROUND

The glymphatic system plays a crucial role in clearing metabolic waste from the central nervous system and is most active during sleep. Patients with obstructive sleep apnea (OSA) have a dysfunctional glymphatic system that correlates with disease severity. In addition, these patients have worse outcomes after surgery. The status of the glymphatic system during the perioperative period is unclear and can be examined with magnetic resonance imaging (MRI)-based diffusion tensor imaging (DTI). This study assessed perioperative glymphatic system changes in OSA surgical patients and possible relationships with perioperative neurocognitive disorders.

METHODS

DTI data from 13 OSA patients having laparoscopic abdominal surgery with general anesthesia were acquired and analyzed using a 3.0-T MRI scanner. Diffusivity maps in the x -axis (D xx ), y -axis (D yy ), z -axis (D zz ), x - y axis (D xy ), y - z axis (D yz ), and x - z axis (D xz ) were calculated. Diffusion values for the projection and association fibers were extracted, and DTI analysis along the perivascular space (ALPS) was performed. The patients' cognition was assessed using the Montreal Cognitive Assessment tool. Evaluations were carried out within 5 days before surgery and within the first 48 hours after surgery.

RESULTS

The ALPS index decreased after surgery, and this correlated with a decrease in general cognition scores and specific memory domains, including visuospatial and delayed recall.

CONCLUSIONS

The glymphatic system in OSA patients is worsened after surgery and this may contribute to an increased risk for long-term postoperative cognitive disorders. This study suggest that the glymphatic system might play a role in the pathophysiology of perioperative neurocognitive disorders and be a potential therapeutic target.

Perioperative neurocognitive dysfunction and role of dexmedetomidine in radical colon cancer surgery in elderly patients

This article explored the application of dexmedetomidine (Dex), a highly selective alpha-2 agonist, in managing postoperative cognitive dysfunction (POCD) in elderly patients undergoing radical colon cancer surgery. Aging is associated with a progressive decline in physiological functions and an increased risk of adverse surgical outcomes, including POCD, which encompasses many neurocognitive disorders that manifest during the perioperative period. The aging population is at a higher risk for POCD, which can lead to prolonged hospital stays, delayed recovery, and increased healthcare costs. Dex has neuroprotective, opioid-sparing, and sympatholytic properties, which reduces the incidence and severity of POCD. Dex was introduced for sedation in patients receiving mechanical ventilation but has since been adopted in anesthesia due to its multifaceted benefits. Its application extends to sedation, analgesia, maintenance of anesthesia, and controlling delirium. Its neuroprotective and anti-inflammatory effects have been explored in managing POCD. This article discussed the broad range of patient and procedure-related risk factors for POCD. Early identification and intervention are crucial to prevent the progression of POCD, which can have severe physical, psychological, and economic consequences. The article underscored the importance of a multidisciplinary approach in managing POCD, involving the optimization of comorbidities, depth of anesthesia monitoring, hemodynamic stability, and cerebral oxygenation monitoring.

Preoperative biomarkers associated with delayed neurocognitive recovery

To identify baseline biomarkers of delayed neurocognitive recovery (dNCR) using monitors commonly used in anesthesia. In this sub-study of observational prospective cohorts, we evaluated adult patients submitted to general anesthesia in a tertiary academic center in the United States. Electroencephalographic (EEG) features and cerebral oximetry were assessed in the perioperative period. The primary outcome was dNCR, defined as a decrease of 2 scores in the global Montreal Cognitive Assessment (MoCA) between the baseline and postoperative period. Forty-six adults (median [IQR] age, 65 [15]; 57% females; 65% American Society of Anesthesiologists (ASA) 3 were analyzed. Thirty-one patients developed dNCR (67%). Baseline higher EEG power in the lower alpha band (AUC = 0.73 (95% CI 0.48-0.93)) and lower alpha peak frequency (AUC = 0.83 (95% CI 0.48-1)), as well as lower cerebral oximetry (68 [5] vs 72 [3], p = 0.011) were associated with dNCR. Higher EEG power in the lower alpha band, lower alpha peak frequency, and lower cerebral oximetry values can be surrogates of baseline brain vulnerability.

Efficiency, Safety, Quality, and Empathy: Balancing Competing Perioperative Challenges in the Older Adults

Although baby boomer generation accounts for a little more than 15% of the US population, the cohort represents a disproportionate percentage of patients undergoing surgery. As this group continues to age, a multitude of challenges have arisen in health care regarding the safest and most effective means of providing anesthesia services to these patients. Many older adults patients may be exquisitely sensitive to the effects of anesthesia and surgery and may experience cognitive and physical decline before, during, or after hospital admission. In this review article, the authors briefly examine the physiologic processes underlying aging and explore steps necessary to deliver safe, empathetic care.

Perioperative approaches to prevent delayed neurocognitive recovery and postoperative neurocognitive disorder in older surgical patients: A systematic review and meta-analysis of randomized controlled trials

Background and Aims

Delayed neurocognitive recovery (DNR) and postoperative neurocognitive disorder (P-NCD) are common postoperative complications affecting older patients. This review evaluates perioperative approaches for preventing DNR and P-NCD in older noncardiac surgical patients.

Material and Methods

We searched databases for relevant articles from inception through June 2022 and updated in May 2023 (PROSPERO ID CRD42022359289). Randomized controlled trials (RCTs) utilizing intervention for DNR and/or P-NCD were included.

Results

We included 39 RCTs involving anesthetic (25 RCTs, 7422 patients) and other pharmacological and nonpharmacological approaches (14 RCTs, 2210 patients). Seventeen trials investigating four interventions were included in the meta-analysis for DNR. Perioperative dexmedetomidine (relative risk [RR]: 0.59, 95% confidence interval [CI]: 0.35-0.97; P = 0.04) and propofol-based total intravenous anesthesia (TIVA) (RR: 0.81, 95% CI: 0.66-0.98; P = 0.03) significantly decreased the risk of DNR versus control. There was no significant decrease in the risk of DNR with regional anesthesia (RA) versus general anesthesia (GA) (RR: 0.89, 95% CI: 0.63-1.26) or bispectral index (BIS) monitoring (RR: 0.79, 95% CI: 0.60-1.04) versus the control groups. Evidence regarding the effects of interventions on P-NCD is limited. Although all included trials were at low risk of bias, the quality of meta-analysis pooled estimates was low.

Conclusions

Our meta-analysis of RCTs showed that dexmedetomidine and TIVA decrease the risk of DNR in older patients undergoing noncardiac surgery by 41% and 20%, respectively, versus control. Further RCTs of adequate power and methodology on the effects of interventions on DNR and P-NCD are warranted.

Electroencephalogram monitoring during anesthesia and critical care: a guide for the clinician

Perioperative anesthetic, surgical and critical careinterventions can affect brain physiology and overall brain health. The clinical utility of electroencephalogram (EEG) monitoring in anesthesia and intensive care settings is multifaceted, offering critical insights into the level of consciousness and depth of anesthesia, facilitating the titration of anesthetic doses, and enabling the detection of ischemic events and epileptic activity. Additionally, EEG monitoring can aid in predicting perioperative neurocognitive disorders, assessing the impact of systemic insults on cerebral function, and informing neuroprognostication. This review provides a comprehensive overview of the fundamental principles of electroencephalography, including the foundations of processed and quantitative electroencephalography. It further explores the characteristic EEG signatures associated wtih anesthetic drugs, the interpretation of the EEG data during anesthesia, and the broader clinical benefits and applications of EEG monitoring in both anesthetic practice and intensive care environments.

Brain health: A concern for anaesthesiologists and intensivists

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

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

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

Distinct brain and neurocognitive transformations after bariatric surgery: a pilot study

Background

Obese patients have worse outcomes after surgery and are at increased risk for perioperative neurocognitive disorders (PND). Our aim was to detail the cognitive trajectories of patients undergoing bariatric surgery (BS) and map distinct structural brain changes using magnetic resonance imaging (MRI) to better understand the association between the vulnerable brain, surgery, and the arc of PND.

Methods

Prospective pilot study with longitudinal comprehensive cognitive assessments and MRI were performed on obese patients scheduled for BS. We analyzed baseline cognitive function and high-resolution T1-/T2-weighted brain images on 19 obese patients [age, 54 (9) years, BMI, 40 (36, 42) kg m-2] and compared with 50 healthy control subjects [age, 52 (6) years; BMI, 25 (24, 27) kg m-2]. Patients were evaluated within five days of BS (baseline), immediately after (within 48h), and follow up at six months.

Results

At baseline, obese patients had significant brain tissue changes seen in MRI and decreased cognitive scores compared to controls (MoCA 26 vs 28, P = 0.017). Surgery induced further gray matter volume and brain tissue changes along with reduced cognitive scores within the immediate postoperative period (MoCA 26 vs 24, P < 0.001). At six months, we observed reversal of brain alterations for most patients and a concomitant rebound of cognitive scores to patient's baseline status.

Conclusions

Bariatric surgery resulted in worsening of preexisting brain structural integrity and lower cognitive function for obese patients compared to baseline. These distinct brain lesions are consistent with specific domains of cognition. Most of these changes reverted to patient's baseline condition within six months after surgery.

Perioperative Considerations in Older Kidney and Liver Transplant Recipients: A Review

With the growth of the older adult population, the number of older adults waitlisted for and undergoing kidney and liver transplantation has increased. Transplantation is an important and definitive treatment for this population. We present a contemporary review of the unique preoperative, intraoperative, and postoperative issues that patients older than 65 y face when they undergo kidney or liver transplantation. We focus on geriatric syndromes that are common in older patients listed for kidney or liver transplantation including frailty, sarcopenia, and cognitive dysfunction; discuss important considerations for older transplant recipients, which may impact preoperative risk stratification; and describe unique challenges in intraoperative and postoperative management for older patients. Intraoperative challenges in the older adult include using evidence-based best anesthetic practices, maintaining adequate perfusion pressure, and using minimally invasive surgical techniques. Postoperative concerns include controlling acute postoperative pain; preventing cardiovascular complications and delirium; optimizing immunosuppression; preventing perioperative kidney injury; and avoiding nephrotoxicity and rehabilitation. Future studies are needed throughout the perioperative period to identify interventions that will improve patients' preoperative physiologic status, prevent postoperative medical complications, and improve medical and patient-centered outcomes in this vulnerable patient population.

Cognitive prehabilitation for older adults undergoing elective surgery: a systematic review and narrative synthesis

Background

Perioperative cognitive maintenance and protection in older adults is an important patient safety imperative. In addition to foundational care, one area of growing interest is integrating cognitive prehabilitation into the surgical trajectory. This review aimed to evaluate the effectiveness and safety of cognitive prehabilitation on cognitive functional capacity and postoperative cognitive outcomes among older adults undergoing elective surgery.

Methods

The MEDLINE, Embase, CENTRAL, CINAHL, PsycINFO, PEDro, CBM, CNKI, WANFANG, and VIP databases were systematically searched up to September 5, 2024, to identify randomized controlled trials published for English or Chinese. Two authors independently completed the study selection process, data extraction process and methodological quality assessment. The Patient, Intervention, Comparison, Outcome, Study design framework was used to construct the search strategy. The predefined primary outcomes of interest included the incidence of postoperative delirium (POD) and the incidence of delayed neurocognitive recovery (dNCR). The quality of the studies was evaluated by the PEDro scale. Owing to the small number of trials and clinical and methodological diversity, a narrative synthesis was undertaken in accordance with the Synthesis Without Meta-analysis guidelines. This study was conducted and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. The certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation system.

Results

Six studies were analysed. These trials involved 645 total participants, with 316 in the intervention group (mean age, 66.0-73.8 years; 38.4-77.8% male) and 329 in the comparator group (mean age, 67.5-72.6 years; 31.8-88.9% male). The effects of preoperative cognitive training on reducing the incidence of dNCR, the incidence of POD, the length of hospital stay and the incidence of postsurgical complications as well as improving postoperative global cognitive function and activities of daily living are quite uncertain. The results of this study should be interpreted with caution owing to the limited number of trials and low to very low certainty of evidence.

Conclusion

Current evidence on the effectiveness and safety of cognitive prehabilitation on cognitive and noncognitive outcomes in older patients undergoing elective surgery is limited and unclear.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=277191, Identifier CRD42021277191.

The utility of remote cognitive screening tools in identifying cognitive impairment in older surgical patients: An observational cohort study

STUDY OBJECTIVES

To determine the prevalence of suspected cognitive impairment using the Centers for Disease Control and Prevention (CDC) cognitive question, Ascertain Dementia Eight-item Questionnaire (AD8), Modified Telephone Interview for Cognitive Status (TICS-M), and Telephone Montreal Cognitive Assessment (T-MoCA), the agreement between each tool beyond chance, and the risk factors associated with a positive screen.

DESIGN

Multicenter prospective study.

SETTING

Remote preoperative assessments.

PATIENTS

307 non-cardiac surgical patients aged ≥65 years.

MEASUREMENTS

Prevalence, Cohen's kappa (κ).

MAIN RESULTS

The T-MoCA detected the highest prevalence of suspected cognitive impairment (28%), followed by the AD8 (17%), CDC cognitive question (9%), and TICS-M (6%). The four screening tools showed poor agreement beyond chance with one another, with the CDC cognitive question and AD8 approaching the threshold for weak agreement (κ = 0.39). Depression was associated with screening positive on the CDC cognitive question (OR: 2.81; 95% CI: 1.04, 7.68). Obstructive sleep apnea (OSA) (OR: 3.10; 95% CI: 1.26, 7.71) and functional disability (OR: 3.74; 95% CI: 1.34, 11.11) were associated with a positive AD8 screen. Older age (OR: 1.56; 95% CI: 1.01, 2.41), male sex (OR: 3.08; 95% CI: 1.09, 9.40), and higher pain level (OR: 1.21; 95% CI: 1.01, 1.47) were associated with a positive TICS-M screen. Similarly, older age (OR: 1.33; 95% CI: 1.03, 1.73), male sex (OR: 2.02; 95% CI: 1.09, 3.83), and higher pain level (OR: 1.15; 95% CI: 1.02, 1.30) were associated with a positive T-MoCA screen.

CONCLUSIONS

The CDC cognitive question, AD8, TICS-M, and T-MoCA were easily implemented during preoperative assessment among older surgical patients. OSA, functional disability, and depression were associated with complaints on the CDC cognitive question and AD8. Older age, male sex, and higher pain level were associated with screening positive on the TICS-M and T-MoCA. Early remote cognitive screening may enhance risk stratification of vulnerable patients.

Association Between Oxidative Stress Markers and Postoperative Delirium in Elderly Patients Undergoing Oncologic Surgery

INTRODUCTION

Postoperative delirium is a frequent complication associated with various types of surgery, particularly among older adults. It is thought that postoperative delirium is the result from an imbalance caused by the overproduction of free oxygen radicals.

OBJECTIVE

To determine an oxidative stress marker that can predict the onset of postoperative delirium in patients undergoing laparoscopic urological surgery for malignant conditions.

MATERIALS AND METHODS

The study involved 29 male and female patients who underwent transperitoneal laparoscopic radical surgery for localized kidney cancer between 2021 and 2024. Blood samples were collected at three intervals: before general anesthesia induction, immediately after surgery, and 24 hours postoperatively. The levels of malondialdehyde (MDA), glutathione peroxidase (GSH) and superoxide dismutase (SOD) were measured. The occurrence of postoperative delirium was evaluated using the Confusion Assessment Method for the ICU (CAM-ICU).

RESULTS

All cases of postoperative delirium emerged within the first seven days after surgery. Out of 29 patients, 11 developed postoperative delirium. Patients in the delirium group exhibited significantly higher malondialdehyde levels at the end of surgery compared to those without delirium (p<0.05). Additionally, superoxide dismutase levels measured before anesthesia induction differed significantly between the delirium and nondelirium groups (p<0.05). Also, glutathione peroxidase (GSH) at the end of surgery significantly decreased in delirium group (p<0.05).

CONCLUSION

The likelihood of developing postoperative delirium in patients undergoing laparoscopic urological surgery for malignant conditions can be anticipated by evaluating oxidative stress markers levels.

Electroencephalographic guided propofol-remifentanil TCI anesthesia with and without dexmedetomidine in a geriatric population: electroencephalographic signatures and clinical evaluation

Elderly and multimorbid patients are at high risk for developing unfavorable postoperative neurocognitive outcomes; however, well-adjusted and EEG-guided anesthesia may help titrate anesthesia and improve postoperative outcomes. Over the last decade, dexmedetomidine has been increasingly used as an adjunct in the perioperative setting. Its synergistic effect with propofol decreases the dose of propofol needed to induce and maintain general anesthesia. In this pilot study, we evaluate two highly standardized anesthetic regimens for their potential to prevent burst suppression and postoperative neurocognitive dysfunction in a high-risk population. Prospective, randomized clinical trial with non-blinded intervention. Operating room and post anesthesia care unit at Hospital Base San José, Osorno/Universidad Austral, Valdivia, Chile. 23 patients with scheduled non-neurologic, non-cardiac surgeries with age > 69 years and a planned intervention time > 60 min. Patients were randomly assigned to receive either a propofol-remifentanil based anesthesia or an anesthetic regimen with dexmedetomidine-propofol-remifentanil. All patients underwent a slow titrated induction, followed by a target controlled infusion (TCI) of propofol and remifentanil (n = 10) or propofol, remifentanil and continuous dexmedetomidine infusion (n = 13). We compared the perioperative EEG signatures, drug-induced changes, and neurocognitive outcomes between two anesthetic regimens in geriatric patients. We conducted a pre- and postoperative Montreal Cognitive Assessment (MoCa) test and measured the level of alertness postoperatively using a sedation agitation scale to assess neurocognitive status. During slow induction, maintenance, and emergence, burst suppression was not observed in either group; however, EEG signatures differed significantly between the two groups. In general, EEG activity in the propofol group was dominated by faster rhythms than in the dexmedetomidine group. Time to responsiveness was not significantly different between the two groups (p = 0.352). Finally, no significant differences were found in postoperative cognitive outcomes evaluated by the MoCa test nor sedation agitation scale up to one hour after extubation. This pilot study demonstrates that the two proposed anesthetic regimens can be safely used to slowly induce anesthesia and avoid EEG burst suppression patterns. Despite the patients being elderly and at high risk, we did not observe postoperative neurocognitive deficits. The reduced alpha power in the dexmedetomidine-treated group was not associated with adverse neurocognitive outcomes.

Postoperative Delirium and the Older Adult: Untangling the Confusion

Postoperative delirium is one of the most prevalent postoperative complications, affecting mostly older adults. Its incidence is expected to rise because of surgical advances, shifting demographics, and increased life expectancy. Although an acute alteration in brain function, postoperative delirium is associated with adverse outcomes, including progressive cognitive decline and dementia, that place significant burdens on patients' lives and healthcare systems. This has prompted efforts to understand the mechanisms of postoperative delirium to provide effective prevention and treatment. There are multiple mechanisms involved in the etiology of postoperative delirium that share similarities with the physiological changes associated with the aging brain. In addition, older patients often have multiple comorbidities including increased cognitive impairment that is also implicated in the genesis of delirium. These tangled connections pinpointed a shift toward creation of a holistic model of the pathophysiology of postoperative delirium. Scientific advancements integrating clinical risk factors, possible postoperative delirium biomarkers, genetic features, digital platforms, and other biotechnical and information technological innovations, will become available in the near future. Advances in artificial intelligence, for example, will aggregate cognitive testing platforms with patient-specific postoperative delirium risk stratification studies, panels of serum and cerebrospinal fluid molecules, electroencephalogram signatures, and gut microbiome features, along with the integration of novel polygenetic variants of sleep and cognition. These advances will allow for the enrollment of high-risk patients into prevention programs and help uncover new pharmacologic targets.

Cognitive trajectories after surgery: Guideline hints for assessment and treatment

Elderly patients who undergo major surgery (not-neurosurgical) under general anaesthesia frequently complain about cognitive difficulties, especially during the first weeks after surgical "trauma". Although recovery usually occurs within a month, about one out of four patients develops full-blown postoperative Neurocognitive disorders (NCD) which compromise quality of life or daily autonomy. Mild/Major NCD affect approximately 10% of patients from three months to one year after major surgery. Neuroinflammation has emerged to have a critical role in the postoperative NCDs pathogenesis, through microglial activation and the release of pro-inflammatory cytokines which increase blood-brain-barrier permeability, enhance movement of leukocytes into the central nervous system (CNS) and favour the neuronal damage. Moreover, pre-existing Mild Cognitive Impairment, alcohol or drugs consumption, depression and other factors, together with several intraoperative and post-operative sequelae, can exacerbate the severity and duration of NCDs. In this context it is crucial rely on current progresses in serum and CSF biomarker analysis to frame neuroinflammation levels, along with establishing standard protocol for neuropsychological assessment (with specific set of tools) and to apply cognitive training or neuromodulation techniques to reduce the incidence of postoperative NCDs when required. It is recommended to identify those patients who would need such preventive intervention early, by including them in pre-operative and post-operative comprehensive evaluation and prevent the development of a full-blown dementia after surgery. This contribution reports all the recent progresses in the NCDs diagnostic classification, pathogenesis discoveries and possible treatments, with the aim to systematize current evidences and provide guidelines for multidisciplinary care.

Comparing analog and digital neurocognitive tests with older adults: a study of the ISPOCD battery vs. a digital test battery from Mindmore

BACKGROUND

Delayed neurocognitive recovery and neurocognitive disorder are common postoperative complications among older adults. The assessment of these complications traditionally relies on analog neurocognitive tests, predominantly using the test battery from the ISPOCD-study as the standard approach. However, analog tests are time-consuming and necessitate trained staff which poses limitations. The potential availability of a digital neurocognitive test as an alternative to the ISPOCD remains unknown. We conducted a comparative study between the analog test battery from ISPOCD and the self-administrated digital test battery developed by Mindmore.

METHODS

We conducted a crossover study with 50 cognitively healthy older adults ≥ 60 years of age recruited in Stockholm Sweden, between February and April 2022. The primary outcome focused on measuring comparability between the two test batteries. Our secondary outcomes included assessing participants' perceptions and attitudes about the tests with qualitative interviews and their usability experiences.

RESULTS

Fifty older adults, mean age 76, female 56%, with a university or college degree 48% participated in the study. The sub tests in two test batteries demonstrated a medium-large correlation (r = 0.3-0.5), except for one measure. For four out of six measures, significant differences were found with medium to large effect sizes, ranging from 0.57-1.43. Two categories were recognized in the qualitative analysis: self-competing in a safe environment, and experience with technology. Participants expressed feeling safe and at ease during the assessment, with some preferring the digital test over the analog. Participants reported a high level of usability with the digital test and a majority participants (n = 47) reported they would undergo the digital test for a potential future surgery.

CONCLUSIONS

The digital test battery developed by Mindmore offers several advantages, including rapid access to test results, easy comprehension, and use for participants, thereby increased accessibility of cognitive screening.

TRIAL REGISTRATION NUMBER

NCT05253612; ClinicalTrials.gov, 24/02/2022.

α5GABAA receptor: A potential therapeutic target for perioperative neurocognitive disorders, a review of preclinical studies

Perioperative neurocognitive disorders (PND) are a common complication in elderly patients following surgery, which not only prolongs the recovery period but also affects their future quality of life and imposes a significant burden on their family and society. Multiple factors, including aging, vulnerability, anesthetic drugs, cerebral oxygen desaturation, and severe pain, have been associated with PND. Unfortunately, no effective drug is currently available to prevent PND. α5 γ-aminobutyric acid subtype A (α5GABAA) receptors have been implicated in cognitive function modulation. Positive or negative allosteric modulators of α5GABAA receptors have been found to improve cognitive impairment under different conditions. Therefore, targeting α5GABAA receptors may represent a promising treatment strategy for PND. This review focuses on preclinical studies of α5GABAA receptors and the risk factors associated with PND, primarily including aging, anesthetics, and neuroinflammation. Specifically, positive allosteric modulators of α5GABAA receptors have improved cognitive function in aged experimental animals. In contrast, negative allosteric modulators of α5GABAA receptors have been found to facilitate cognitive recovery in aged or adult experimental animals undergoing anesthesia and surgery but not in aged experimental animals under anesthesia alone. The reasons for the discordant findings have yet to be elucidated. In preclinical studies, different strategies of drug administration, as well as various behavioral tests, may influence the stability of the results. These issues need to be carefully considered in future studies.

Research progress of microglial surface receptors in perioperative neurocognitive disorders

Perioperative neurocognitive disorder (PND) is a common complication in the perioperative period, which not only prolongs the hospitalization of patients, increases the cost of treatment, but even increases the postoperative mortality of patients, bringing a heavy burden to families and society. Mechanism exploration involves anesthesia and surgery that lead to microglial activation, promote the synthesis and secretion of inflammatory factors, cause an inflammatory cascade, aggravate nerve cell damage, and lead to cognitive dysfunction. It is believed that microglia-mediated neuroinflammatory responses play a vital role in the formation of PND. Microglia surface receptors are essential mediators for microglia to receive external stimuli, regulate microglial functional status, and carry out intercellular signal transmission. Various microglial surface receptors trigger neuroinflammation, damage neurons, and participate in the development and progression of PND by activating microglia. In this study, the roles of immunoglobulin receptors, chemokine receptors, purinergic receptors, and pattern recognition receptors in microglia surface receptors in PND were reviewed, to provide a reference for the mechanism research, prevention, and treatment of PND.

Association between postoperative delirium and adverse outcomes in older surgical patients: A systematic review and meta-analysis

STUDY OBJECTIVE

To assess the incidence of postoperative delirium and its outcomes in older non-cardiac surgical patients.

DESIGN

A systematic review and meta-analysis with multiple databases searched from inception to February 22, 2022.

SETTING

Postoperative assessments.

PATIENTS

Non-cardiac and non-neurological surgical patients aged ≥60 years with and without postoperative delirium. Included studies must report ≥1 postoperative outcome. Studies with a small sample size (N < 100 subjects) were excluded.

MEASUREMENTS

Outcomes comprised the pooled incidence of postoperative delirium and its postoperative outcomes, including mortality, complications, unplanned intensive care unit admissions, length of stay, and non-home discharge. For dichotomous and continuous outcomes, OR and difference in means were computed, respectively, with a 95% CI.

MAIN RESULTS

Fifty-four studies (20,988 patients, 31 elective studies, 23 emergency studies) were included. The pooled incidence of postoperative delirium was 19% (95% CI: 16%, 23%) after elective surgery and 32% (95% CI: 25%, 39%) after emergency surgery. In elective surgery, postoperative delirium was associated with increased mortality at 1-month (OR: 6.60; 95% CI: 1.58, 27.66), 6-month (OR: 5.69; 95% CI: 2.33, 13.88), and 1-year (OR: 2.87; 95% CI: 1.63, 5.06). The odds of postoperative complications, unplanned intensive care unit admissions, prolonged length of hospital stay, and non-home discharge were also higher in delirium cases. In emergency surgery, patients with postoperative delirium had greater odds of mortality at 1-month (OR: 3.56; 95% CI: 1.77, 7.15), 6-month (OR: 2.60; 95% CI: 1.88, 3.61), and 1-year (OR: 2.30; 95% CI: 1.77, 3.00).

CONCLUSIONS

Postoperative delirium was associated with higher odds of mortality, postoperative complications, unplanned intensive care unit admissions, length of hospital stay, and non-home discharge. Prevention and perioperative management of delirium may optimize surgical outcomes.

Efficiency, Safety, Quality, and Empathy: Balancing Competing Perioperative Challenges in the Elderly

Although baby boomer generation accounts for a little more than 15% of the US population, the cohort represents a disproportionate percentage of patients undergoing surgery. As this group continues to age, a multitude of challenges have arisen in health care regarding the safest and most effective means of providing anesthesia services to these patients. Many elderly patients may be exquisitely sensitive to the effects of anesthesia and surgery and may experience cognitive and physical decline before, during, or after hospital admission. In this review article, the authors briefly examine the physiologic processes underlying aging and explore steps necessary to deliver safe, empathetic care.

The future of ambulatory surgery for geriatric patients

The elderly segment of the population is growing rapidly worldwide. Older patients comprise a disproportionate percentage of the surgical caseload. Physiological changes are inevitable with aging; some may impact a patient's response to anesthesia and surgery. Careful evaluation of an elderly patient preoperatively is vital to proper patient selection for ambulatory surgeries, particularly for complex and lengthy procedures. Cognitive issues, frailty, and geriatric syndromes make a patient vulnerable and sometimes unsuitable for certain ambulatory procedures. Preoperative planning and interventions may improve outcomes for the elderly patient undergoing ambulatory surgery.

Usability and feasibility of a digital cognitive screening tool measuring older adults' early postoperative neurocognitive recovery: a protocol for a pilot study

INTRODUCTION

Delayed neurocognitive recovery, also identified as early postoperative cognitive decline (POCD), is a common complication after surgery, with advanced age being the most important risk factor. As the geriatric population is increasing worldwide, and number of older adults undergoing surgery continues to rise, so will the incidence of POCD. Only a small proportion use digital cognitive tests for measuring postoperative neurocognitive performance compared with analogue tests. This study aims to evaluate a digital cognitive screening tool, Mindmore Postoperative version (Mindmore-P), in a perioperative setting to determine its feasibility and usability, and to compare preoperative cognition with early postoperative neurocognitive performance. Further, to determine associations between neurocognitive performance and perioperative factors as well as to explore patients' experiences of early neurocognitive recovery.

METHODS AND ANALYSIS

We will include 50 patients (aged ≥60 years) undergoing elective abdominal surgery under general anaesthesia. Cognitive functions will be measured with Mindmore-P preoperatively and on postoperative day (POD) 1 or 2 as well as 2-3 weeks after surgery. Preoperatively, frailty, (Clinical Frailty Scale), depression (Geriatric Depression Scale-15), functional status (12-item WHO Disability Assessment Schedule 2.0) and pre-recovery status (Swedish web version Quality of Recovery Scale, SwQoR) will be measured. Delirium will be assessed by Nu-DESC (Nursing Delirium Screening Scale) twice a day, with start on POD 1 and until the patient is discharged from the hospital. Outcomes at 2-3 weeks postoperatively are postoperative recovery (SwQoR), depression, functional status and usability (System Usability Scale) of Mindmore-P. Postoperative recovery will also be measured POD 1 or 2. We will also explore feasibility and experience of early postoperative neurocognitive recovery with interviews approximately 1 month after surgery.

ETHICS AND DISSEMINATION

This study is approved by the Swedish Ethical Review Authority (REC Reference: 2022-03593-01) and will follow the principles outlined in the 1964 Helsinki Declaration and its later amendments. Results from this study will be disseminated in peer-reviewed journals, scientific conferences and in social media.

TRIAL REGISTRATION NUMBER

NCT05564195.

Postoperative delirium: identifying the patient at risk and altering the course: A narrative review

Postoperative delirium (POD) is a common neurocognitive syndrome seen in older patients after major surgery. POD is linked to longer stays in hospital and intensive care, a greater incidence of postoperative complications, worse functional outcome, and higher mortality. Researchers have not yet fully elucidated the exact pathophysiology of POD. Several risk factors that contribute to the development of POD have been identified, such as advanced age, cardiac or hip surgery, preoperative cognitive decline or delirium, disturbances in brain levels of neurotransmitters and information processing, oxidative stress and neuro-inflammation. Identifying patients at risk for POD enables a more precise and efficient allocation of medical resources and facilitates POD prevention and management. The present review addresses how to identify patients at risk of POD and summarizes the currently available evidence and best-practice recommendations for peri-operative management and prevention of POD.

Intergenerational Perioperative Neurocognitive Disorder

Accelerated neurocognitive decline after general anesthesia/surgery, also known as perioperative neurocognitive disorder (PND), is a widely recognized public health problem that may affect millions of patients each year. Advanced age, with its increasing prevalence of heightened stress, inflammation, and neurodegenerative alterations, is a consistent contributing factor to the development of PND. Although a strong homeostatic reserve in young adults makes them more resilient to PND, animal data suggest that young adults with pathophysiological conditions characterized by excessive stress and inflammation may be vulnerable to PND, and this altered phenotype may be passed to future offspring (intergenerational PND). The purpose of this narrative review of data in the literature and the authors' own experimental findings in rodents is to draw attention to the possibility of intergenerational PND, a new phenomenon which, if confirmed in humans, may unravel a big new population that may be affected by parental PND. In particular, we discuss the roles of stress, inflammation, and epigenetic alterations in the development of PND. We also discuss experimental findings that demonstrate the effects of surgery, traumatic brain injury, and the general anesthetic sevoflurane that interact to induce persistent dysregulation of the stress response system, inflammation markers, and behavior in young adult male rats and in their future offspring who have neither trauma nor anesthetic exposure (i.e., an animal model of intergenerational PND).

The role of TREM1 in regulating microglial polarization in sevoflurane-induced perioperative neurocognitive disorders

Microglia-mediated neuroinflammatory responses play a key role in perioperative neurocognitive disorders (PND). Triggering receptor expressed on myeloid cells-1 (TREM1) has been shown to be a key regulator of inflammation. However, its role in PND remains largely unknown. This study aimed to evaluate the role of TREM1 in sevoflurane-induced PND. We applied AAV knockdown TREM1 in hippocampal microglia in aging mice. The mice were then subjected to neurobehavioral and biochemical testing after the intervention of sevoflurane. We found that sevoflurane inhalation can cause PND in mice, increase hippocampal TREM1 expression, polarize microglia to M1 type, upregulate TNF-α and IL-1β expression (pro-inflammatory), and inhibit TGF-β and IL-10 expression (anti-inflammatory). Knocking down TREM1 can improve sevoflurane-induced cognitive dysfunction, reduce M1 type marker iNOS, and increase M2 type marker ARG, improving the neuroinflammation. TREM1 is a target for sevoflurane-induced PND prevention.

Postoperative Outcomes in Elderly Patients Undergoing Cardiac Surgery With Preoperative Cognitive Impairment: A Systematic Review and Meta-Analysis

BACKGROUND

Older patients with preoperative cognitive impairment are at risk for increased postoperative complications after noncardiac surgery. This systematic review and meta-analysis aimed to determine the association between preoperative cognitive impairment and dementia and postoperative outcomes in older surgical patients after cardiac surgery.

METHODS

Eight electronic databases were searched from inception to January 4, 2022. Inclusion criteria were cardiac surgery patients ≥60 years of age; preoperative cognitive impairment; ≥1 postoperative complication reported; comparator group with no preoperative cognitive impairment; and written in English. Using a random-effects model, we calculated effect sizes as odds ratio (OR) and standardized mean differences (SMDs). Risk of random error was assessed by applying trial sequential analysis.

RESULTS

Sixteen studies (62,179 patients) were included. Preoperative cognitive impairment was associated with increased risk of delirium in older patients after cardiac surgery (70.0% vs 20.5%; OR, 8.35; 95% confidence interval [CI], 4.25-16.38; I2, 0%; P < .00001). Cognitive impairment was associated with increased hospital length of stay (LOS; SMD, 0.36; 95% CI, 0.20-0.51; I2, 22%; P < .00001) and intensive care unit (ICU) LOS (SMD, 0.39; 95% CI, 0.09-0.68; I2, 70%; P = .01). No significant association was seen for 30-day mortality (1.7% vs 1.1%; OR, 2.58; 95% CI, 0.64-10.44; I2, 55%; P = .18).

CONCLUSIONS

In older patients undergoing cardiac surgery, cognitive impairment was associated with an 8-fold increased risk of delirium, a 5% increase in absolute risk of major postoperative bleeding, and an increase in hospital and ICU LOS by approximately 0.4 days. Further research on the feasibility of implementing routine neurocognitive testing is warranted.