Does anaesthesia cause postoperative cognitive dysfunction? A randomised study of regional versus general anaesthesia in 438 elderly patients

National survey on perioperative cognitive dysfunction

BACKGROUND

Perioperative cognitive dysfunction (PCD) is a very prevalent clinical syndrome due to the progressive aging of the surgical population.The aim of our study is to evaluate the clinical practice of Spanish anesthesiologists surveyed regarding this entity.

MATERIAL AND METHODS

Prospective online survey conducted by the Neurosciences Section and distributed by SEDAR.

RESULTS

544 responses were obtained, with a participation rate of 17%. 54.4% of respondents never make a preoperative assessment of cognitive impairment, only 7.5% always do it. 79.6% lack an intraoperative management protocol for the patient at risk of PCD. In the anesthetic planning, only 23.3% of the patients was kept in mind. Eighty-nine percent considered regional anesthesia with or without sedation preferable to general anesthesia for the prevention of PCD. 88.8% considered benzodiazepines to present a high risk of PCD. 71.7% considered that anesthetic depth monitoring could prevent postoperative cognitive deficit. Routine evaluation of postoperative delirium is low, only 14%. More than 80% recognize that PCD is underdiagnosed.

CONCLUSIONS

Among Spanish anesthesiologists surveyed, PCD is still a little known and underappreciated entity. It is necessary to raise awareness of the need to detect risk factors for PCD, as well as postoperative assessment and diagnosis. Therefore, the development of guidelines and protocols and the implementation of continuing education programs in which anesthesiologists should be key members of multidisciplinary teams in charge of perioperative care are suggested.

Comparison of regional vs. general anesthesia on the risk of dementia: a systematic review and meta-analysis

Background

Dementia is a gradual and ongoing cognitive decline due to damage to nerve cells in the brain. This meta-analysis aimed to assess the potential relationship between regional anesthesia (RA) and the risk of dementia.

Methods

Electronic databases including Embase, Medline, Google Scholar, and Cochrane Library were searched for studies investigating the association between RA and dementia risk from inception to March 2022. The primary outcome was the risk of dementia in patients who underwent RA (RA group) and those who received general anesthesia (GA group). Secondary outcomes included identifying other potential risk factors for dementia and comparing dementia risk between individuals receiving RA and those not receiving surgery/anesthesia (placebo group).

Results

Eight cohort studies published between 2014 and 2023 were included in this analysis. A meta-analysis of the available data demonstrated no differences in baseline characteristics and morbidities (i.e., age, male proportion, hypertension, diabetes, depression, and severe comorbidities) between the RA and GA groups (all p > 0.05). Initial analysis revealed that the risk of dementia was higher in the GA group than in the RA group (HR = 1.81, 95% CI = 1.29-2.55, p = 0.007, I 2 = 99%, five studies). However, when a study featuring a relatively younger population was excluded from the sensitivity analysis, the results showed a similar risk of dementia (HR, 1.17; p = 0.13) between the GA and RA groups. The pooled results revealed no difference in dementia risk between the RA and placebo groups (HR = 1.2, 95% CI = 0.69-2.07, p = 0.52, I 2 = 68%, three studies). Sensitivity analysis revealed that the evidence was not stable, suggesting that limited datasets precluded strong conclusions on this outcome. Anxiety, stroke history, hypertension, diabetes, hyperlipidemia, and diabetes are potential predictors of dementia.

Conclusion

Our results emphasize that, while RA could be protective against dementia risk compared to GA, the association between the type of anesthesia and dementia risk might vary among different age groups. Owing to the significant prevalence of dementia among older people and their surgical needs, further investigations are warranted to clarify the association between dementia risk and regional anesthesia.Systematic review registration: https://www.crd.york.ac.uk/prospero/, CRD42023411324.

Longitudinal study on the trajectory and influencing factors of cognitive dysfunction in lung transplantation patients

INTRODUCTION

Lung transplantation is an effective method for treating end-stage lung disease. It prolongs the survival time of patients, improves the quality of life, and prevents the degree of mental disability. In particular, postoperative cognitive dysfunction (POCD) is one of the complications after lung transplantation. Despite this, longitudinal studies on the identification and heterogeneity of cognitive dysfunction subgroup trajectories in transplant patients are lacking. Therefore, our study aimed to evaluate the factors that influence POCD in lung transplant patients.

METHODS

This prospective longitudinal study included patients who underwent lung transplantation at the transplant center of Wuxi People's Hospital from September 2022 to September 2023. Patients with lung transplants were evaluated at 8 days (T1), 1 month (T2), 3 months (T3), and 6 months (T4) after the operation. The general information questionnaire evaluated cognitive functions using the Montreal Cognitive Assessment (MoCA) numerical rating scale (NRS) and the digital pain assessment to obtain the POCD values. Latent category growth model (LCGM) analysis was used to identify heterogeneous POCD subgroups in the four observation periods. Univariate and logistic regression analyses were used to identify factors affecting POCD classification and independent risk factors.

RESULTS

Based on clinical outcomes, 79 patients completed all four surveys, of whom 16 were lost during the follow-up period (loss rate, 16.8%). The cognitive function by MoCA NRS score was 14.18 ± 5.32 points on day 8 (T1), 22.51 ± 5.13 points at 1 month (T2), 25.44 ± 3.61 at 3 months (T3), and 27.04 ± 3.03 points at 6 months (T4) after lung transplantation, showing an increasing trend. The LCGM, used to fit the trajectory of MoCA scores, observed a heterogeneous trajectory of changes in lung transplant patients. Based on this analysis, patients could be divided into two categories: those with high risk (25,32%) and those with low risk (54,68%). The single-factor analysis identified that POCD values were affected by early postoperative rehabilitation exercise, degree of pain, intensive care unit (ICU) stay time, and donor lung cold ischemia time (all P < 0.05). Using the low-risk group as the reference class, logistic regression analysis showed that the model could correctly classify the subjects.

CONCLUSION

Our 6-month observation of lung transplant patients showed that the degree of cognitive dysfunction had an overall downward trend and that patients could be divided into two trajectories of high and low risk for POCD. Early postoperative rehabilitation exercise, degree of pain, ICU stay time, and donor lung cold ischemia time were all influencing factors for POCD in lung transplant patients.

Anesthesia, Anesthetics, and Postoperative Cognitive Dysfunction in Elderly Patients

Postoperative cognitive dysfunction (POCD) remains a major issue that worsens the prognosis of elderly surgery patients. This article reviews the current research on the effect of different anesthesia methods and commonly utilized anesthetics on the incidence of POCD in elderly patients, aiming to provide an understanding of the underlying mechanisms contributing to this condition and facilitate the development of more reasonable anesthesia protocols, ultimately reducing the incidence of POCD in elderly surgery patients.

Transforaminal Full-Endoscopic Ventral Facetectomy: Midterm Results and Factors Associated with Poor Surgical Outcomes

BACKGROUND

 Full-endoscopic spine surgery (FESS) is a well-established procedure for herniated nucleus pulposus. It is a minimally invasive surgery that can be performed under local anesthesia through only an 8-mm skin incision. With improvements in surgical equipment such as high-speed drills, the indications for FESS have expanded to include lumbar spinal stenosis (LSS). We perform a transforaminal full-endoscopic ventral facetectomy (TF-FEVF) for unilateral nerve root-type lateral recess stenosis (LRS) using a transforaminal approach under local anesthesia.The aim of this study was to examine the postoperative results of TF-FEVF for LRS and to identify factors associated with poor surgical outcomes. 85 patients who underwent TF-FEVF for LRS under local anesthesia. Clinical outcomes were determined by visual analog scale (VAS) and the modified MacNab criteria. Evaluation was performed using magnetic resonance imaging (MRI), computed tomography (CT), and flexion-extension radiographs.

METHODS

 This study involved 85 patients (47 males and 38 females) who underwent TF-FEVF for LRS. The mean age was 70.5 years and the mean follow-up duration was 14.8 months. Data were collected on sex, age, level of operation, diagnosis, history of spine surgery at the same level, and duration of follow-up. The diagnosis was categorized as LSS with or without disk bulging. Clinical evaluation was performed using the VAS and modified MacNab criteria. MRI was used to evaluate the degree of disk degeneration, vertebral endplate degeneration, disk height, thickening of the ligamentum flavum, and stenosis. Bony stenosis was evaluated using CT. Sagittal translation and sagittal angulation were also measured by flexion-extension radiographs, and the Cobb angle was measured using a standing front view radiograph. All variables were compared between patients with excellent/good outcomes (E/G group) and those with fair/poor outcomes (F/P group) using the modified MacNab criteria.

RESULTS

 Postoperative VAS showed that leg pain decreased from 59.0 ± 28.6 preoperatively to 17.9 ± 27.2 at the final follow-up (p < 0.01) and that lower back pain also decreased from 60.7 ± 26.6 preoperatively to 27.3 ± 28.6 at final follow-up (p < 0.01). According to the modified MacNab criteria, the results during the final follow-up were excellent in 39 cases, good in 21 cases, fair in 13 cases, and poor in 12 cases. There were no significant differences in sex, age, diagnosis, history of spine surgery, and duration of follow-up periods between the 60 cases (70.6%) in the E/G group and the 25 cases (29.4%) in the F/P group. Imaging evaluation revealed statistically significant differences between the E/G group and the F/P group in intervertebral angle flexion (3.2 vs. 0.4 degrees; p < 0.05), sagittal angulation (4.3 vs. 8.1 degrees; p < 0.05), slip in flexion (0.9 vs. 2.8 mm; p < 0.05), sagittal translation (0.7 vs. 1.6 mm; p < 0.05), and Cobb angle (-0.5 vs. -1.9 degrees; p < 0.05).

CONCLUSION

 Midterm results of TF-FEVF were generally favorable; factors contributing to good or poor TF-FEVF outcomes were large sagittal angulation, large sagittal translation, and concave side.

Long-term cognitive outcomes after surgery and anesthesia: what we find depends on where we look

Purpose of review

To review how anecdote and narrative medicine, primary cohort studies, epidemiological studies, and the dementia literature can be bridged to understand long-term postoperative cognitive decline.

Recent findings

Primary cohort studies have measured recoverable declines in memory and executive function after major surgery, but less-appreciated sources also offer critical insights. Anecdote reveals that functionally-impactful cognitive decline may persist after physical recovery in some patients despite modern medications and monitoring, and that physicians are unprepared to address patients' cognitive concerns. However, epidemiological studies reproducibly demonstrate that elective surgery has no, or a negligible, average impact on cognition in older patients. Cognitively provocative factors - like medical hospital admissions or health factors like diabetes and smoking - are common in late life, and surgery likely contributes minimally to long-term cognitive change for most patients.

Summary

Patients should be reassured that, while anecdotes of durable cognitive change after surgery are easily accessible, most patients experience cognitive recovery after major surgery. However, those who do not recover deserve characterization of their symptoms and investigation of modifiable causes to facilitate cognitive recovery.

Postoperative cognitive dysfunction after beach chair positioning compared to supine position in orthopaedic surgery in the elderly

INTRODUCTION

Postoperative cognitive dysfunction (POCD) occurs in up to 26% of patients older than 60 years 1 week after non-cardiac surgery. Intraoperative beach chair positioning (BCP) is advantageous for some types of shoulder surgery. However, this kind of positioning leads to a downward bound redistribution of blood volume, with possible hypoperfusion of the brain. We hypothesized that patients > 60 years undergoing orthopaedic shoulder surgery in a BCP might experience more POCD than patients operated in the supine position (SP).

MATERIAL AND METHODS

A single-centre, prospective observational trial of 114 orthopaedic patients was performed. Study groups were established according to the type of intraoperative positioning. Anaesthesiological management was carried out similarly in both groups, including types of anaesthetics and blood pressure levels. POCD was evaluated using the Trail Making Test, the Letter-Number Span and the Regensburger Word Fluency Test. The frequency of POCD 1 week after surgery was considered primary outcome.

RESULTS

Baseline characteristics, including duration of surgery, were comparable in both groups. POCD after 1 week occurred in 10.5% of SP patients and in 21.1% of BCP patients (p = 0.123; hazard ratio 2.0 (CI 95% 0.794-5.038)). After 4 weeks, the incidence of POCD decreased (SP: 8.8% vs. BCP: 5.3%; p = 0.463). 12/18 patients with POCD showed changes in their Word Fluency Tests. Near-infrared spectroscopy (NIRS) values were not lower in patients with POCD compared to those without POCD (54% (50/61) vs. 57% (51/61); p = 0.671).

CONCLUSION

POCD at 1 week after surgery tended to occur more often in patients operated in beach chair position compared to patients in supine position without being statistically significant.

Factors associated with postoperative quality of life in patients with intertrochanteric fracture

Introduction

Intertrochanteric fractures, which make up the majority of hip fractures, are a common and serious injury that can greatly impact quality of life. Treatment of such fractures comprises nearly half of the costs contributed to hip fractures. Identifying the factors affecting the functional outcomes of patients after intertrochanteric fracture can help to reduce burden of disease for the patient and healthcare system. The present study investigated the factors underlying the worsening of short form-36 score (SF-36) scores for intertrochanteric fracture patients.

Materials and methods

This retrospective cohort study was designed based on data from our clinic. All consecutive patients with intertrochanteric fractures from November 2016 to September 2020 were reviewed. The exclusion criteria included patients having a second injury or having had previous surgery related to the hip and those with incomplete data. Baseline characteristics of patients were extracted from annotated records. The lab data were acquired from the electronic hospital system. The outcomes were SF-36 scores obtained by phone contact with patients or their families. Statistical analysis was conducted in SPSS.

Results

A total of 310 patients were included in the current study. The female gender, advanced age, history of diabetes, thyroid malfunction, cancer, osteoporosis, anticoagulant use and blood transfusion were identified as risk factors for lower SF-36 scores. Low levels of haemoglobin before surgery, blood urea nitrogen (BUN), BUN/Creatinine, and white blood count values correlated with lower SF-36 scores.

Conclusion

Numerous contextual variables affected the functional outcomes of the patients. Consideration of these factors could be helpful in reducing costs and improving the quality of life for intertrochanteric fracture patients.

Full-endoscopic spine surgery in oldest old patients aged over 90 years:A case report

BACKGROUND

Transforaminal full-endoscopic spine surgery (FESS) is the least invasive spinal surgery and can be performed under local anesthesia. In Japan, the population is rapidly aging and the number of spinal surgeries performed in the elderly is also increasing.

OBJECT

In this report, we describe 3 patients aged 90 years or older in whom we performed FESS under local anesthesia.

CASE

The first case was a 90-year-old man who presented with severe leg pain. He had multiple medical comorbidities and was unsuitable for general anesthesia. We performed FESS. After surgery, the leg pain resolved with full recovery of muscle strength. He was discharged with no perioperative complications. The second case was a 90-year-old man who presented with severe leg pain. MRI showed a herniated nucleus pulposus and foraminal stenosis at L4/5. We performed FESS. The leg pain improved immediately after surgery. The third case was a 91-year-old woman in whom we diagnosed left L5 radiculopathy due to foraminal stenosis at L5/S1. After surgery, her leg pain was relieved.

CONCLUSION

FESS is a good surgical procedure for elderly patients who are in a poor general condition because it is minimally invasive and can be performed under local anesthesia with early mobilization. J. Med. Invest. 71 : 169-173, February, 2024.

Postoperative Delirium and Cognitive Dysfunction after General and Regional Anesthesia: A Systematic Review and Meta-Analysis

Background: Perioperative disorders of neurocognitive function are a set of heterogeneous conditions, which include transient post-operative delirium (POD) and more prolonged post-operative cognitive dysfunction (POCD). Since the number of annually performed surgical procedures is growing, we should identify which type of anesthesia is safer for preserving neurocognitive function. The purpose of this study was to compare the effect of general anesthesia (GA) and regional anesthesia (RA) in patients undergoing surgical procedures under general anesthesia and regional anesthesia. Material and methods: We searched for randomized controlled studies, which studied post-operative cognitive outcomes after general and regional anesthesia in the adult patient population. Results: Thirteen articles with 3633 patients: the RA group consisted of 1823 patients, and the GA group of 1810 patients, who were selected for meta-analysis. The overall effect of the model shows no difference between these two groups in terms of risk for post-operative delirium. The result is insensitive to the exclusion of any study. There was no difference between RA and GA in terms of post-operative cognitive dysfunction. Conclusions: There was no statistically significant difference between GA and RA in the incidence of POD. There was no statistically significant difference in the incidence of POCD per-protocol analysis, psychomotor/attention tests (preoperative/baseline, post-operative), memory tests (postoperatively, follow up), mini-mental state examination score 24 h postoperatively, post-operative reaction time three months postoperatively, controlled oral word association test, and digit copying test. There were no differences in the incidence of POCD in general and regional anesthesia at one week postoperatively, three months postoperatively, or total events (one week or three months). The incidence of post-operative mortality also did not differ between two groups.

Association between endocrine therapy and cognitive decline in older women with early breast cancer: Findings from the prospective CLIMB study

INTRODUCTION

Studies investigating the long-term effects of breast cancer treatment on cognition in older women with breast cancer are lacking, even though preserving cognition is highly valued by the older population. Specifically, concerns have been raised regarding the detrimental effects of endocrine therapy (ET) on cognition. Therefore, we investigated cognitive functioning over time and predictors for cognitive decline in older women treated for early breast cancer.

METHODS

We prospectively enrolled Dutch women aged ≥70 years with stage I-III breast cancer in the observational CLIMB study. The Mini-Mental State Examination (MMSE) was performed before ET initiation and after 9, 15 and 27 months. Longitudinal MMSE scores were analysed and stratified for ET. Linear mixed models were used to identify possible predictors of cognitive decline.

RESULTS

Among the 273 participants, the mean age was 76 years (standard deviation 5), and 48% received ET. The mean baseline MMSE score was 28.2 (standard deviation 1.9). Cognition did not decline to clinically meaningful differences, irrespective of ET. MMSE scores of women with pre-treatment cognitive impairments slightly improved over time (significant interaction terms) in the entire cohort and in women receiving ET. High age, low educational level and impaired mobility were independently associated with declining MMSE scores over time, although the declines were not clinically meaningful.

CONCLUSION

Cognition of older women with early breast cancer did not decline in the first two years after treatment initiation, irrespective of ET. Our findings suggest that the fear of declining cognition does not justify the de-escalation of breast cancer treatment in older women.

The Management of Postoperative Cognitive Dysfunction in Cirrhotic Patients: An Overview of the Literature

Background and objectives: Postoperative cognitive dysfunction (POCD) represents a decreased cognitive performance in patients undergoing general anesthesia for major surgery. Since liver cirrhosis is associated with high mortality and morbidity rates, cirrhotic patients also assemble many risk factors for POCD. Therefore, preserving cognition after major surgery is a priority, especially in this group of patients. The purpose of this review is to summarize the current knowledge regarding the effectiveness of perioperative therapeutic strategies in terms of cognitive dysfunction reduction. Data Collection: Using medical search engines such as PubMed, Google Scholar, and Cochrane library, we analyzed articles on topics such as: POCD, perioperative management in patients with cirrhosis, hepatic encephalopathy, general anesthesia in patients with liver cirrhosis, depth of anesthesia, virtual reality in perioperative settings. We included 115 relevant original articles, reviews and meta-analyses, and other article types such as case reports, guidelines, editorials, and medical books. Results: According to the reviewed literature, the predictive capacity of the common clinical tools used to quantify cognitive dysfunction in cirrhotic settings is reduced in perioperative settings; however, novel neuropsychological tools could manage to better identify the subclinical forms of perioperative cognitive impairments in cirrhotic patients. Moreover, patients with preoperative hepatic encephalopathy could benefit from specific preventive strategies aimed to reduce the risk of further neurocognitive deterioration. Intraoperatively, the adequate monitoring of the anesthesia depth, appropriate anesthetics use, and an opioid-sparing technique have shown favorable results in terms of POCD. Early recovery after surgery (ERAS) protocols should be implemented in the postoperative setting. Other pharmacological strategies provided conflicting results in reducing POCD in cirrhotic patients. Conclusions: The perioperative management of the cognitive function of cirrhotic patients is challenging for anesthesia providers, with specific and targeted therapies for POCD still sparse. Therefore, the implementation of preventive strategies appears to remain the optimal attitude. Further research is needed for a better understanding of POCD, especially in cirrhotic patients.

Efficiency of probiotics in elderly patients undergoing orthopedic surgery for postoperative cognitive dysfunction: a study protocol for a multicenter, randomized controlled trial

BACKGROUND

Postoperative cognitive dysfunction (POCD) refers to a neurological dysfunction after a major surgery and anesthesia. It is common in elderly patients and is characterized by impairment in consciousness, orientation, thinking, memory, and executive function after surgical anesthesia. However, at present, there is no definite preventive or treatable strategy for it. Previous animal experiments showed that giving probiotics to mice before operation can prevent POCD, but there is a lack of clinical evidence. This study aims to intervene with the intestinal flora imbalance using probiotics during the perioperative period to reduce the incidence of POCD in elderly patients after orthopedic surgery and to provide new ideas and methods for the clinical prevention and treatment of POCD.

METHODS

A multicenter, double-blind, placebo-controlled clinical trial will be performed to evaluate the efficacy of probiotics in elderly patients undergoing orthopedic surgery. Participants (n = 220) will receive probiotics (Peifeikang, Live Combined Bifidobacterium, 210 mg per capsule, twice a day, four capsules each time, which contains Bifidobacterium longum, Lactobacillus acidophilus and Streptococcus faecalis no less than 1.0 × 10⁷ CFU viable bacteria respectively) or placebo from 1 day before surgery to 6 days after surgery. Neuropsychological tests will be performed 1 day before surgery and 1 week and 1 month after surgery. The main outcome of this study is the incidence of POCD 7 days after surgery. Our secondary objective is to assess the incidence of POCD 1 month after surgery; the cognitive status will be determined based on a telephone interview and will be evaluated via TICS-m; postoperative delirium will be assessed 7 days after surgery using the Confusion Assessment Method (CAM).

DISCUSSION

Discovering the correlation between the intestinal microbiota and POCD is an important breakthrough. Based on the key role of the intestinal microbiota in other cognitive disorders, we hope that probiotics can reduce its incidence in elderly orthopedic patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04017403. Registered on August 15, 2019.

Microglia participate in postoperative cognitive dysfunction by mediating the loss of inhibitory synapse through the complement pathway

BACKGROUND

Elderly patients after surgery are prone to cognitive decline known as postoperative cognitive dysfunction (POCD). Several studies have shown that the microglial activation and the increase of complement protein expression in hippocampus induced by surgery may be related to the pathogenesis of POCD. The purpose of this study was to determine whether microglia and complement system were involved in cognitive dysfunction in aged mice.

METHODS

The POCD model was established by exploratory laparotomy in 15-month-old male C57BL/6J mice and animal behavioral tests were performed to test hippocampal-dependent memory capacity. Minocycline was used to suppress the activation of microglia, and complement 3 receptor inhibitor was used to suppress the association between microglia and complement 3. Western blot and immunofluorescence were used to detect the microglial activation, complement protein, and synaptic protein expressions.

RESULTS

Operation induced hippocampal-dependent memory impairment (P < 0.01), which was accompanied by microglial activation (P < 0.01). There was also a significant reduction in inhibitory synaptic protein expression in the hippocampus of mice in the surgery group (P < 0.01). However, minocycline, a microglia inhibitor, rescued all the above changes. In addition, C3RI intervention inhibited the phagocytosis of inhibitory synapses by microglia (P < 0.05) and improved the cognitive function of mice (P < 0.01).

CONCLUSION

Microglia participate in postoperative cognitive dysfunction by mediating inhibitory synaptic loss through the complement pathway.

A Single Episode of Cortical Spreading Depolarization Increases mRNA Levels of Proinflammatory Cytokines, Calcitonin Gene-Related Peptide and Pannexin-1 Channels in the Cerebral Cortex

Cortical spreading depolarization (CSD) is the neuronal correlate of migraine aura and the reliable consequence of acute brain injury. The role of CSD in triggering headaches that follow migraine aura and brain injury remains to be uncertain. We examined whether a single CSD occurring in awake animals modified the expression of proinflammatory cytokines (Il1b, TNF, and Il6) and endogenous mediators of nociception/neuroinflammation-pannexin 1 (Panx1) channel and calcitonin gene-related peptide (CGRP), transforming growth factor beta (TGFb) in the cortex. Unilateral microinjury of the somatosensory cortex triggering a single CSD was produced in awake Wistar rats. Three hours later, tissue samples from the lesioned cortex, intact ipsilesional cortex invaded by CSD, and homologous areas of the contralateral sham-treated cortex were harvested and analyzed using qPCR. Three hours post-injury, intact CSD-exposed cortexes increased TNF, Il1b, Panx1, and CGRP mRNA levels. The strongest upregulation of proinflammatory cytokines was observed at the injury site, while CGRP and Panx1 were upregulated more strongly in the intact cortexes invaded by CSD. A single CSD is sufficient to produce low-grade parenchymal neuroinflammation with simultaneous overexpression of Panx1 and CGRP. The CSD-induced molecular changes may contribute to pathogenic mechanisms of migraine pain and post-injury headache.

Considerations for Corneal Surgery With Patients in the 10th Decade of Life

PURPOSE

The purpose of this study was to report the indications, ocular and systemic comorbidities, and surgical outcomes of corneal transplantation in patients older than 90 years.

METHODS

A retrospective review was conducted to identify individuals 90 years and older who underwent corneal transplantation surgery at the Bascom Palmer Eye Institute between January 2013 and October 2020. Outcomes included best-corrected visual acuity and graft survival over time. Paired t tests were used to compare visual acuity preoperatively versus postoperatively. Graft survival was evaluated with Kaplan-Meier curves.

RESULTS

Fifty-eight eyes of 52 consecutive individuals were included. The mean age of individuals was 92 ± 2 years; 26.9% were male; and 48.1% self-identified as non-Hispanic White and 38.5% as Hispanic. Postoperative follow-up was 14.7 ± 12.1 months. Of the 58 eyes, 44.8% (26/58) underwent penetrating keratoplasty, 46.6% (27/58) Descemet stripping automated endothelial keratoplasty, and 6.9% (4/58) keratoprosthesis. All surgeries were performed under monitored local anesthesia, without major complications. Surgical indications included pseudophakic bullous keratopathy (36.2%), glaucoma-associated corneal decompensation (27.6%), Fuchs endothelial dystrophy (25.9%), and perforated corneal ulceration (19.0%). The best-corrected visual acuity improved by 0.32 (95% confidence interval 0.14-0.50; P < 0.01) as early as 1 month postoperatively, and vision gains were sustained for at least 12 months. Graft survival probability at 12 months was 88%.

CONCLUSIONS

Corneal transplantation is a safe and successful procedure in restoring the visual acuity for patients older than 90 years after careful preoperative evaluation. Further research is needed to evaluate the impact of corneal transplantation on quality of life in patients in the 10th decade of life.

Electroacupuncture Stimulation Suppresses Postoperative Inflammatory Response and Hippocampal Neuronal Injury

Postoperative cognitive dysfunction (POCD) is consequence of anesthesia and surgery that primarily affects older people. The prevention and treatment of POCD has drawn an increasing attention in recent decades. Here, we established the animal model mimicked POCD after femoral fracture surgery, and analyze the effect of acupuncture stimulation on postoperative cognitive function after femoral fracture surgery. Compared with the mock group, the cognitive function performance was significantly decreased both in the anaesthesia group and the surgery group, between which the symptoms were more severe in the surgery group. The peripheral inflammation response and the neuron impairment and inflammation response in the hippocampus were observed in the surgery group, but only peripheral inflammation response was detected in the anaesthesia group. These findings indicated the POCD was the synergistic outcome of anaesthesia and surgical stimulation but with different pathogenic mechanism. The surgery with mental tri-needles (surgery+MTN) group outperformed the surgery group in terms of cognitive function performance. The peripheral inflammation response and the neuron impairment and inflammation response in the hippocampus was significantly reduced by the electroacupuncture stimulation. Our findings indicated the protection of electroacupuncture form POCD after femoral fracture surgery is related to the inhibition of inflammation response and neuron impairment.

The impact of regional versus general anesthesia on postoperative neurocognitive outcomes in elderly patients undergoing hip fracture surgery: A systematic review and meta-analysis

BACKGROUND

Randomized trials have shown conflicting results regarding differences in outcomes according to anesthesia type on the prevalence of postoperative delirium (POD) or postoperative cognitive dysfunction (POCD) in hip surgery patients. The aim of this Meta analysis is to compare the effect of general and regional anesthesia in older patients undergoing hip fracture surgery.

METHODS

A literature search for meta-analysis was performed using Pubmed, The Cochrane Library, Embase and Web of Science citation index for randomized controlled trials (RCTs) to compare the regional anesthesia (RA) to general anesthesia (GA) for postoperative outcomes in elderly undergoing hip fracture surgery till June 2022. The primary outcomes were the incidence of POD or POCD at 24 h, 3 days and 7 days postoperatively. The secondary outcomes were 30 days mortality rate and other adverse events. The risk of bias was assessed using the Cochrane methodology.

RESULTS

Eight studies including 3555 elderly patients over 65 years old showed that there was no significant difference in the prevalence of POD or POCD between RA and GA at 24 h [OR 0.73; 95% coincidence interval (CI) 0.19, 2.71, I2 = 53%; n = 452; P = 0.63], at 3 days [OR 1.03; 95% CI 0.79, 1.35, I2 = 0%; n = 1362; P = 0.82], at 7 days [OR 0.79; 95% CI 0.41, 1.52, I2 = 51%; n = 1336; P = 0.47], respectively. No significant differences were observed in the incidence of other adverse events.

CONCLUSIONS

No significant difference was found in the incidence of cognitive dysfunction after either general or regional anesthesia in elderly patients. Our finding of similar outcomes at 24 h, 3 days and 7 days postoperatively with either technique suggests that anesthesia choices for hip-fracture surgery may be based on the individual characteristics of each patient rather than on anticipated differences in clinical outcomes.

Early Postoperative Cognitive Dysfunction in Women Undergoing Elective and Emergent Caesarian Section under General Anaesthesia: A Comparative Study

Background

Postoperative cognitive dysfunction (POCD) following cesarean section (CS) is a growing and underestimated problem with unknown mechanisms. Studies suggest that general anesthesia (GA) plays a role in the development of early POCD.

Objectives

This study aimed to assess the incidence of early POCD after elective and emergent CS under GA.

Methods

We assessed the difference between the elective and emergent groups regarding the mini-mental state examination (MMSE), hemodynamic effects such as mean blood pressure (MBP), and heart rate (HR). Paired t-test was applied for intragroup comparison, and Student's t-test (or Mann-Whitney U test, as appropriate) for intergroup comparison.

Results

MMSE one hour after the operation was significantly lower than preoperative MMSE in the emergent group, and the MMSE tended to return to normal values faster in the elective than in the emergent group. Moreover, we found a significantly lower MBP and higher HR (at 15, 30, and 45 minutes) in both groups compared to preoperative values. Regarding intergroup comparison, MBP (at 30 minutes) significantly decreased in the elective group compared to the emergent group.

Conclusions

There was a significantly lower POCD, especially at the first hour postoperatively, in the elective CS than in the emergent CS. Elective CS might have a positive effect on the women's health as a mode of delivery.

Transient neuroinflammation following surgery contributes to long-lasting cognitive decline in elderly rats via dysfunction of synaptic NMDA receptor

Background

Perioperative neurocognitive disorders (PNDs) are considered the most common postoperative complication in geriatric patients. However, its pathogenesis is not fully understood. Surgery-triggered neuroinflammation is a major contributor to the development of PNDs. Neuroinflammation can influence N-methyl-D-aspartate receptor (NMDAR) expression or function which is closely associated with cognition. We, therefore, hypothesized that the persistent changes in NMDAR expression or function induced by transient neuroinflammation after surgery were involved in the development of PNDs.

Methods

Eighteen-month-old male Sprague–Dawley rats were subjected to abdominal surgery with sevoflurane anesthesia to establish the PNDs animal model. Then, we determined the transient neuroinflammation by detecting the protein levels of proinflammatory cytokines and microglia activation using ELISA, western blot, immunohistochemistry, and microglial morphological analysis from postoperative days 1–20. Persistent changes in NMDAR expression were determined by detecting the protein levels of NMDAR subunits from postoperative days 1–59. Subsequently, the dysfunction of synaptic NMDAR was evaluated by detecting the structural plasticity of dendritic spine using Golgi staining. Pull-down assay and western blot were used to detect the protein levels of Rac1-GTP, phosphor-cofilin, and Arp3, which contribute to the regulation of the structural plasticity of dendritic spine. Finally, glycyrrhizin, an anti-inflammatory agent, was administered to further explore the role of synaptic NMDAR dysfunction induced by transient neuroinflammation in the neuropathogenesis of PNDs.

Results

We showed that transient neuroinflammation induced by surgery caused sustained downregulation of synaptic NR2A and NR2B subunits in the dorsal hippocampus and led to a selective long-term spatial memory deficit. Meanwhile, the detrimental effect of neuroinflammation on the function of synaptic NMDARs was shown by the impaired structural plasticity of dendritic spines and decreased activity of the Rac1 signaling pathways during learning. Furthermore, anti-inflammatory treatment reversed the downregulation and hypofunction of synaptic NR2A and NR2B and subsequently rescued the long-term spatial memory deficit.

Conclusions

Our results identify sustained synaptic NR2A and NR2B downregulation and hypofunction induced by transient neuroinflammation following surgery as important contributors to the development of PNDs in elderly rats.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02528-5.

Functional MRI Changes in Patients after Thyroidectomy under General Anesthesia

Cognitive changes affecting elderly patients following surgery under anesthesia have drawn significant attention and have been investigated in considerable depth. Resting-state functional magnetic resonance imaging (rs-fMRI) can be used to assess changes in brain functional connectivity (FC) associated with postoperative changes in cognition, a common complication in seniors undergoing surgery. In this study, we recruited 20 patients over 55 of age and scheduled an elective thyroidectomy under general anesthesia to assess perioperative changes in brain FC density (FCD) in patients undergoing thyroidectomy under general anesthesia using rs-fMRI. All 20 patients underwent a series of clinical, quantitative, neurological, and neuropsychological tests and fMRI examinations on the day before surgery (Day 0) and 7 days after surgery (Day 7). The following tests were conducted on all patients: the Minimental State Examination (MMSE), the digit symbol substitution test (DSST), the trail making test (part A), the verbal fluency test, and Warrington's recognition memory test (WRMT). FMRI data were acquired using a 3T MR system; the FCD values were calculated using the REST software package. We used paired t-tests to compare the FCD between Day 7 and Day 0. A value of p < 0.05 was considered to reflect statistical significance. The postoperative FCD was significantly reduced in the supplementary motor area (SMA). Analyses of the percentage changes of errors in the WRMT revealed a significant and negative correlation with the mean percentage change of FCD in the SMA (Spearman's r = −0.54, 95% CI: (-0.80, -0.12), p = 0.014). Postoperative changes in FCD in the SMA may be associated with the perioperative neurocognitive changes in patients undergoing partial thyroidectomy under general anesthesia.

Effect of Dexmedetomidine on Early Postoperative Cognitive Function in Patients Undergoing Arthroscopic Shoulder Surgery in Beach Chair Position: A Randomized Double-Blind Study

This study sought to determine whether intraoperative dexmedetomidine infusion might reduce the incidence of postoperative cognitive dysfunction (POCD) and alleviate the neuroinflammatory response in patients who have undergone arthroscopic shoulder surgery. A total of 80 patients over 60 years of age who had undergone arthroscopic shoulder surgery in the beach chair position were randomly allocated to either the dexmedetomidine group (Group D) or the control group (Group C). Dexmedetomidine (0.6 μg/kg/h) or a comparable amount of normal saline was infused into each group during the surgery. The early incidence of POCD was assessed by comparing cognitive tests on the day before and 1 d after surgery. The neuroinflammatory response with the S100 calcium-binding protein B (S100β) assay was compared prior to anesthetic induction and 1 h following surgery. The incidence of POCD was comparable between groups D (n = 9, 22.5%) and C (n = 9, 23.7%) (p = 0.901). However, the results of the cognitive test revealed a significant difference between the groups after surgery (p = 0.004). Although the S100β levels measured at the end of surgery were significantly higher than those at baseline in both groups (p < 0.001), there was no difference between the groups after the surgery (p = 0.236). Our results suggest that intraoperative dexmedetomidine infusion neither reduce the incidence of early POCD nor alleviated the neuroinflammatory response in patients undergoing arthroscopic shoulder surgery.

Cognitive Impairment Following Clinical or Recreational Use of Gammahydroxybutyric Acid (GHB): A Systematic Review

BACKGROUND

GHB (gamma-hydroxybutyric acid; sodium oxybate) is a general anaesthetic that is clinically used for the treatment of narcolepsy, cataplexy, alcohol withdrawal and alcohol relapse prevention. In addition, GHB is recreationally used. Most clinical and recreational users regard GHB as an innocent drug devoid of adverse effects, despite its high dependence potential and possible neurotoxic effects. At high doses, GHB may lead to a comatose state. This paper systematically reviews possible cognitive impairments due to clinical and recreational GHB use.

METHODS

PubMed and PsychINFO were searched for literature data about the acute and residual cognitive deficits following GHB use. This review is conducted using the PRISMA protocol.

RESULTS

A total of 43 reports covering human and animal data on GHB-induced cognitive impairments were eligible and reviewed. This systematic review found no indication for cognitive impairments after clinical GHB use. However, it supports the view that moderate GHB use may result in acute short-term cognitive impairments, whereas regular high-dose GHB use and/or multiple GHB-induced comas are probably neurotoxic resulting in long-term residual cognitive impairments.

CONCLUSION

These results emphasize the need for awareness among clinicians and recreational users to minimize negative health consequences of recreational GHB use, particularly when high doses are used and GHB-induced comas occur.

Neuroinflammation as the Underlying Mechanism of Postoperative Cognitive Dysfunction and Therapeutic Strategies

Postoperative cognitive dysfunction (POCD) is a common neurological complication following surgery and general anesthesia, especially in elderly patients. Severe cases delay patient discharge, affect the patient’s quality of life after surgery, and are heavy burdens to society. In addition, as the population ages, surgery is increasingly used for older patients and those with higher prevalences of complications. This trend presents a huge challenge to the current healthcare system. Although studies on POCD are ongoing, the underlying pathogenesis is still unclear due to conflicting results and lack of evidence. According to existing studies, the occurrence and development of POCD are related to multiple factors. Among them, the pathogenesis of neuroinflammation in POCD has become a focus of research in recent years, and many clinical and preclinical studies have confirmed the correlation between neuroinflammation and POCD. In this article, we reviewed how central nervous system inflammation occurred, and how it could lead to POCD with changes in peripheral circulation and the pathological pathways between peripheral circulation and the central nervous system (CNS). Furthermore, we proposed some potential therapeutic targets, diagnosis and treatment strategies at the cellular and molecular levels, and clinical applications. The goal of this article was to provide a better perspective for understanding the occurrence of POCD, its development, and preventive strategies to help manage these vulnerable geriatric patients.

Cytokine changes in cerebrospinal fluid and plasma after emergency orthopaedic surgery

Neuroinflammation after surgery and its contribution to peri-operative neurocognitive disorders (PND) is not well understood. Studying the association between central and peripheral cytokines and neuroinflammation is a prelude to the development of treatments for PND. Here, we investigate the hypotheses that there is a greater cytokine response in cerebrospinal fluid (CSF) than plasma after orthopaedic surgery, and that plasma cytokine levels are directly related to CSF cytokine levels, indicating that plasma cytokine levels may have potential as biomarkers of neuroinflammation. Patients admitted with a fractured neck of femur were invited to participate in this study. Participants had a spinal catheter inserted just prior to induction of anaesthesia. Samples of blood and CSF were taken before, immediately after, and on the first day following emergency surgery. The catheter was then removed. Samples were analysed for the presence of ten cytokines by immunoassay. A spinal catheter was successfully inserted in 11 participants during the 18-month study period. Five plasma cytokines (IL-4, IL-6, IL-10, IL-12p70 and IL-13) rose significantly following surgery, whereas all ten CSF cytokines rose significantly (IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, IFN-γ and TNF-α) (adjusted-p < 0.05). Central (CSF) cytokine levels were consistently higher than their peripheral (plasma) counterparts after surgery, with some patients having a particularly marked neuroinflammatory response. The greatest increases occurred in IL-8 in CSF and IL-6 in plasma. There were significant, strong positive correlations between several of the measured cytokines in the CSF after surgery, but far fewer in plasma. There was no significant correlation between cytokine levels in the plasma and CSF at each of the three time points. To our knowledge, this is the first study to analyse paired samples of plasma and CSF for cytokine levels before and after emergency orthopaedic surgery. This study demonstrates that following surgery for a fractured neck of femur, there is a far greater rise in cytokines in the CSF compared to plasma. The lack of correlation between peripheral and central cytokines suggests measurement of peripheral cytokines are not necessarily related to which patients may have a large neuroinflammatory response.

Cognitive Recovery by Decade in Healthy 40- to 80-Year-Old Volunteers After Anesthesia Without Surgery

BACKGROUND

Postoperative delirium and postoperative cognitive dysfunction are the most common complications for older surgical patients. General anesthesia may contribute to the development of these conditions, but there are little data on the association of age with cognitive recovery from anesthesia in the absence of surgery or underlying medical condition.

METHODS

We performed a single-center cohort study of healthy adult volunteers 40 to 80 years old (N = 71, mean age 58.5 years, and 44% women) with no underlying cognitive dysfunction. Volunteers underwent cognitive testing before and at multiple time points after 2 hours of general anesthesia consisting of propofol induction and sevoflurane maintenance, akin to a general anesthetic for a surgical procedure, although no procedure was performed. The primary outcome was time to recovery to cognitive baseline on the Postoperative Quality of Recovery Scale (PQRS) within 30 days of anesthesia. Secondary cognitive outcomes were time to recovery on in-depth neuropsychological batteries, including the National Institutes of Health Toolbox and well-validated paper-and-pencil tests. The primary hypothesis is that time to recovery of cognitive function after general anesthesia increases across decades from 40 to 80 years of age. We examined this with discrete-time logit regression (for the primary outcome) and linear mixed models for interactions of age decade with time postanesthesia (for secondary outcomes).

RESULTS

There was no association between age group and recovery to baseline on the PQRS; 36 of 69 (52%) recovered within 60-minute postanesthesia and 63 of 69 (91%) by day 1. Hazard ratios (95% confidence interval) for each decade compared to 40- to 49-year olds were: 50 to 59 years, 1.41 (0.50-4.03); 60 to 69 years, 1.03 (0.35-3.00); and 70 to 80 years, 0.69 (0.25-1.88). There were no significant differences between older decades relative to the 40- to 49-year reference decade in recovery to baseline on secondary cognitive measures.

CONCLUSIONS

Recovery of cognitive function to baseline was rapid and did not differ between age decades of participants, although the number in each decade was small. These results suggest that anesthesia alone may not be associated with cognitive recovery in healthy adults of any age decade.

Global research trends in perioperative care for the elderly: a bibliometric and visualized study

PURPOSE

Aged surgical patients are at a relatively higher risk of morbidity and mortality than younger surgical patients. The present study aimed to investigate the trends and research status of perioperative care for the elderly in the anesthesiology field.

METHODS

We screened manuscripts published between May 31, 1991, and May 31, 2020, from the Web of Science Core Collection (WoSCC). A clustered network was derived from all references cited in all of the included manuscripts. The top authors, journals, institutions, countries, keywords, co-cited articles, and trends were identified through bibliometric analysis and visualization using CiteSpace 5.8.R3 and VOSviewer 1.6.15.

RESULTS

We included a total of 1860 manuscripts published between 1991 and 2020. The number of publications on perioperative care for the elderly sharply increased from 2014 onwards. The United States of America and the University of California, San Francisco were the leading publication country (24.8%, 461/1860) and institution (2.6%, 48/1860), respectively. High-frequency keywords in cluster analysis included the type of anesthesia, postoperative pain management, postoperative cognitive dysfunction, and postoperative delirium, indicating postoperative cognitive dysfunction and postoperative delirium remain the focus areas for research in perioperative care for the elderly. Organ function protection was the new research focus according to the burst detection analysis of top keywords.

CONCLUSIONS

The number of studies on perioperative care for the elderly has increased apparently worldwide. Postoperative cognitive dysfunction and postoperative delirium remain primary research focus areas. Organ function protection appears to be the second most highly researched topic in the perioperative care for the elderly.

A Comparative Study on the Effects of Ketofol, Dexmedetomidine, and Isofol in Anesthesia of Candidates for Dilatation and Curettage

Background

Dilatation and curettage (D & C) is one of the relatively common surgeries among women. Familiarity with the analgesics, along with their different uses and specific characteristics, can help to determine the best and most appropriate drug to control pain in the patients.

Objectives

This study aimed to compare the effects of ketofol, dexmedetomidine, and isofol in anesthesia of candidates for D & C.

Methods

In this double-blind clinical trial, 150 candidates for D & C surgeries with ASA class 1 and 2 were included. Patients were randomly divided into three groups. The first group received ketamine + propofol, the second group received dexmedetomidine, and the third group received isofol (isoflurane + propofol). Any hemodynamic changes or respiratory disorders, including apnea or hypoventilation, drop in the level of blood oxygen saturation, and the need for respiratory support, were recorded and compared.

Results

Hypoventilation was observed in 47 patients in isofol group, 18 in the dexmedetomidine group, and 42 in ketofol group. Also, 48 patients in the isofol group, eight in the dexmedetomidine group, and 33 in the ketofol group experienced apnea. Moreover, 17 patients in the dexmedetomidine group, 35 in the ketofol group, and eight in the isofol group experienced bradycardia. The rate of bradycardia was significantly higher in the dexmedetomidine group (70%) compared to the other two groups, and the rate of hypotension was significantly higher in the isofol group (P = 0.001).

Conclusions

According to the results, dexmedetomidine was associated with fewer complications during general anesthesia in D & C surgery.

Propofol Versus Sevoflurane General Anaesthesia for Selective Impairment of Attention Networks After Gynaecological Surgery in Middle-Aged Women: A Randomised Controlled Trial

PURPOSE

Attention is an essential component of cognitive function that may be impaired after surgery with anaesthesia. Propofol intravenous anaesthesia and sevoflurane inhalational anaesthesia are frequently used in gynaecological surgery. However, which type of anaesthetic has fewer cognitive effects postoperatively remains unclear. We compared the differences in attention network impairment after surgery in women receiving propofol versus sevoflurane general anaesthesia.

PATIENTS AND METHODS

Eighty-three patients with gynaecological diseases who were 40-60 years of age were involved in the study. All patients underwent elective gynaecological surgery under either total intravenous anaesthesia or sevoflurane inhalational anaesthesia, depending on randomisation. The efficiencies of the three attention networks were captured using the attention network test preoperatively and on the 1st and 5th postoperative days.

RESULTS

Both groups of patients showed differences in impairments on the 1st and 5th postoperative days. Pairwise comparisons indicated that the alerting and orienting networks of patients in the propofol group were impaired to a greater extent than those of patients in the sevoflurane group on the 1st postoperative day, while the executive control network was impaired to a lesser extent. On the 5th postoperative day, the alerting networks of both groups recovered to the baseline level. Patients in the propofol group still showed impairment of the orienting network, while patients in the sevoflurane group recovered to baseline. For the executive control network, patients in the sevoflurane group still exhibited more severe impairment than those in the propofol group.

CONCLUSION

In middle-aged women, propofol impaired orienting and alerting networks more than sevoflurane, while sevoflurane showed more residual impairment of the executive control network.

Cognitive behavioral therapy cannot relieve postoperative pain and improve joint function after total knee arthroplasty in patients aged 70 years and older

PURPOSE

A randomized controlled trial was conducted to investigate whether cognitive behavioral therapy (CBT) can improve postoperative pain, knee function, and negative emotion in patients aged 70 years and older who underwent total knee arthroplasty (TKA).

METHODS

This study used randomized, parallel group, controlled trial to divide the included 90 patients into CBT group and usual care group. The primary outcome measure of the study was the Visual Analogue Scale (VAS) at activity. The secondary outcome measures included the Self-Rating Anxiety Scale (SAS), Self-Rating Depression Scale (SDS), Knee Range of Motion (ROM), Oxford Knee Score (OKS), Hospital for Special Surgery Knee Rating Scale (HSS), analgesics dose, and postoperative complications.

RESULTS

83 patients who met the criteria were randomized into CBT group and usual care group. In the SAS, score of the CBT group decreased by 4.3 points at 7th day and 8.2 at 14th day after surgery with respect to preoperative SAS score, the usual care group increased by 1.5 at 7th day and decreased 1.1 at 14th day, and tended to be similar at 3rd month after surgery. There were no significant differences at 7th and 14th day in SDS, however, score of the CBT group was 5.8 and the usual care group was 1.9 at 3rd month after surgery. No statistically significant differences in VAS at activity, ROM, OKS, HSS, analgesics frequency, and postoperative complications between two groups.

CONCLUSIONS

CBT was superior to usual care group in relieving anxiety at 7th day and 14th day, and depression at 3rd month, however, CBT cannot relieve postoperative pain and improve joint function after TKA in patients aged 70 years and older.

Sleep, Pain, and Cognition: Modifiable Targets for Optimal Perioperative Brain Health

The prevention of perioperative neurocognitive disorders is a priority for patients, families, clinicians, and researchers. Given the multiple risk factors present throughout the perioperative period, a multicomponent preventative approach may be most effective. The objectives of this narrative review are to highlight the importance of sleep, pain, and cognition on the risk of perioperative neurocognitive disorders and to discuss the evidence behind interventions targeting these modifiable risk factors. Sleep disruption is associated with postoperative delirium, but the benefit of sleep-related interventions is uncertain. Pain is a risk factor for postoperative delirium, but its impact on other postoperative neurocognitive disorders is unknown. Multimodal analgesia and opioid avoidance are emerging as best practices, but data supporting their efficacy to prevent delirium are limited. Poor preoperative cognitive function is a strong predictor of postoperative neurocognitive disorder, and work is ongoing to determine whether it can be modified to prevent perioperative neurocognitive disorders.

Surgery Trauma Severity but not Anesthesia Length Contributes to Postoperative Cognitive Dysfunction in Mice

BACKGROUND

Perioperative, modifiable factors contributing to perioperative neurocognitive disorders (PND) have not been clearly defined.

OBJECTIVE

To determine the contribution of anesthesia lengths and the degrees of surgical trauma to PND and neuroinflammation, a critical process for PND.

METHODS

Three-month-old C57BL/6J mice were subjected to 2 h or 6 h isoflurane anesthesia plus a 5 min or 15 min left common carotid artery exposure (surgery) in a factorial design (two factors: anesthesia with two levels and surgery with three levels). Their learning and memory were tested by Barnes maze and novel object recognition paradigms. Blood, spleen, and hippocampus were harvested for measuring interleukin (IL)-6 and IL-1β. Eighteen-month-old C57BL/6J mice (old mice) were subjected to 6 h isoflurane anesthesia or 2 h isoflurane anesthesia plus 15 min surgery and then had learning and memory tested.

RESULTS

Three-month-old mice with 15 min surgery (long surgery) under 2 h or 6 h anesthesia performed poorly in the learning and memory tests compared with controls. Anesthesia alone or anesthesia plus 5 min surgery did not affect mouse performance in these tests. Similarly, only mice with long surgery but not mice with other experimental conditions had increased IL-6 and IL-1β in the blood, spleen, and hippocampus and decreased spleen weights. Splenocytes were found in the hippocampus after surgery. Similarly, old mice with long surgery but not the mice with isoflurane anesthesia alone had poor performance in the Barnes maze and novel object recognition tests.

CONCLUSION

Surgical trauma, but not anesthesia, contributes to the development of PND and neuroinflammation. Splenocytes may modulate these processes.

Transcutaneous electrical acupoint stimulation for postoperative cognitive dysfunction in geriatric patients with gastrointestinal tumor: a randomized controlled trial

Background

This study aimed to evaluate the effect of perioperative transcutaneous electrical acupoint stimulation (TEAS) on postoperative cognitive dysfunction (POCD) in older patients who were diagnosed with gastrointestinal tumor and received radical resection of gastrointestinal tumors under general anesthesia.

Methods

A total of 68 patients who received radical resection of gastrointestinal tumors under general anesthesia were randomly divided into two groups. TEAS group patients received TEAS treatment. The treatment time was 30 min before the induction of anesthesia until the end of the surgery, 1 day before operation and from the first day to the third day after the operation. Except on the day of surgery, we treated the patients for 30 min once a day. In the sham TEAS group, the electronic stimulation was not applied and the treatment was the same as the TEAS group. The primary outcome was perioperative cognition evaluated by the Mini-Mental State Examination (MMSE) and secondary outcomes were the perioperative level of interleukin-6 (IL-6), S100 calcium-binding protein β (S100β), and C-reactive protein (CRP).

Results

The postoperative score of MMSE, orientation, memory, and short-term recall in the sham TEAS group was significantly lower than the preoperative and TEAS group (P < 0.05). The incidence of POCD in the TEAS group (21.88%) was lower than those in the sham TEAS group (40.63%). S100β, IL-6, and CRP in the TEAS group were significantly lower than those in the sham TEAS group on the third day after the operation (P< 0.05). Postoperative S100β, IL-6, and CRP in two groups were significantly higher than those before operation except for S100β on the third day after the operation in the TEAS group (P < 0.05).

Conclusions

Perioperative TEAS treatment reduced the postoperative inflammatory response and increased the postoperative cognitive function score and decrease the incidence of POCD in geriatric patients with gastrointestinal tumor.

Trial registration

ClinicalTrials.gov NCT04606888. Registered on 27 October 2020. https://register.clinicaltrials.gov.

Assessment of a digital game as a neuropsychological test for postoperative cognitive dysfunction

OBJECTIVE

Postoperative cognitive dysfunction may result from worsening in a condition of previous impairment. It causes greater difficulty in recovery, longer hospital stays, and consequent delay in returning to work activities. Digital games have a potential neuromodulatory and rehabilitation effect. In this study, a digital game was used as a neuropsychological test to assess postoperative cognitive dysfunction, with preoperative patient performance as control.

METHODS

It was a non-controlled study, with patients selected among candidates for elective non-cardiac surgery, evaluated in the pre- and postoperative periods. The digital game used has six phases developed to evaluate selective attention, alternating attention, visuoperception, inhibitory control, short-term memory, and long-term memory. The digital game takes about 25 minutes. Scores are the sum of correct answers in each cognitive domain. Statistical analysis compared these cognitive functions pre- and post-surgery using a generalized linear mixed model (ANCOVA).

RESULTS

Sixty patients were evaluated, 40% male and 60% female, with a mean age of 52.7 ± 13.5 years. Except for visuoperception, a reduction in post-surgery scores was found in all phases of the digital game.

CONCLUSION

The digital game was able to detect decline in several cognitive functions postoperatively. As its completion is faster than in conventional tests on paper, this digital game may be a potentially recommended tool for assessing patients, especially the elderly and in the early postoperative period.

Effects of dopamine transporter changes in the ventral tegmental area of the midbrain on cognitive function in aged rats

The pathogenesis of Perioperative neurocognitive disorders (PND) is a synergistic effect of many factors. Up to now, the exact mechanism remains unclear. The dopamine pathway in the brain is one of the paths involved in the means of cognitive function. Therefore, the purpose of this study was to investigate the relationship between changes in dopamine transporters in the ventral tegmental area (VTA) of the midbrain and postoperative cognitive dysfunction in elderly rats. In this study, a mental dysfunction model in elderly rats was established after splenectomy under general anesthesia. Eighty male SD rats, aged 18-20 months, with a body mass of 300-500 g. Randomly divided into eight groups: Normal group (Normal, N) and Sham group (sham, S), Model 3 day group(PND, P3), Model 7 day group(PND, P7), Virus 3 days AAV·DAT·RNAi (AAV3), Virus 7 days AAV·DAT·RNAi (AAV7), Virus control for three days AAV·NC(NC3), Virus control for seven days AAV·NC(NC7). The results show that knockdown of dopamine transporter in the VTA region can significantly improve the cognitive dysfunction of elderly rats after surgery. These results suggest that dopamine transporter in the VTA region is involved in cognitive dysfunction in elderly rats. The effect of DAT changes in the VTA region on postoperative cognitive function in elderly rats may be related to the regulation of α-syn and Aβ1-42 protein aggregation in the hippocampus.

[Perioperative Medicine in Visceral Surgery in the Elderly Patient from an Anaesthesiological Perspective]

Demographic change is leading to an increasing number of old patients both in our society and in hospitals. With increasing age, not only the number of pre-existing conditions increases, but also the postoperative complication rate and mortality. Ultimately, however, it is not age that is decisive, but the condition of the patient and his or her capacity to face the physical and mental challenges of a surgical procedure. Frail patients are particularly at risk of complications, and an essential strategy - known as prehabilitation - is to put them in a better state pre-operatively through physical and mental training, as well as nutritional counselling. Delirium is one of the most frequent postoperative complications. Measures such as refraining from premedication with benzodiazepines, measuring the depth of anaesthesia, refraining from long-acting opioids, performing fast-track surgery, and providing glasses/hearing aids quickly postoperatively can reduce the risk of delirium. Close interdisciplinary consultation between surgeons, anaesthetists, geriatricians and physiotherapists is essential to coordinate the perioperative procedure and reduce the perioperative risk for elderly patients.

Effects of Apolipoprotein Ε ε4 allele on early postoperative cognitive dysfunction after anesthesia

BACKGROUND

Postoperative cognitive dysfunction (POCD) is one of the main causes of morbidity after noncardiac surgery; however, the pathogenic mechanisms of POCD have remained unclear until now. In this study, we performed a pilot study to investigate the association between apolipoprotein E (ApoE) ε4 and POCD in older patients undergoing intravenous anesthesia (IVA) and inhalation anesthesia (IAA).

METHODS

In total, 180 patients from Shenzhen People's Hospital were recruited and randomly divided into an IVA group and an IAA group. The IVA group and IAA group received propofol and sevoflurane treatment, respectively. Within 7 days after surgery, the mini-mental state examination (MMSE) was used daily to assess the cognitive function of both groups of patients. The genotypes of the ApoE gene were detected using the restriction fragment length polymorphism technique. In addition, the serum levels of (soluble protein-100β) S‑100β and (Interleukin- 6) L‑6 were also analyzed.

RESULTS

Compared to the preoperative and IVA groups, the MMSE score in the IAA group significantly decreased at 3 days after surgery. Furthermore, the IAA group had a higher percentage of patients who scored less than 25 points than the IVA group at 3 days after surgery. The decrease in the MMSE score was closely related to the ApoE ε4 allele in the IAA group, but this correlation was not observed in the IVA group. The levels of S‑100β and IL‑6 were increased sharply in patients with the ε4/ε4 genotype who received IAA compared with IVA at 1 day after surgery.

CONCLUSION

The results of the study indicated that the ApoΕ ε4/ε4 genotype was a risk factor for early POCD in older patients undergoing sevoflurane anesthesia.

Neuropsychological Tests in Post-operative Cognitive Dysfunction: Methods and Applications

Post-operative cognitive dysfunction (POCD) is a neurological complication that relatively frequently occurs in older people after anesthesia/surgery, with varying durations and significant differences in the severity of cognitive impairment. POCD is mainly characterized by memory loss mostly without consciousness disorders, accompanied by abnormal emotions, behaviors, and language, mostly without consciousness disorder. The clinical performance of POCD lacks specificity but can reflect the severity of cognitive impairment in patients. The diagnosis of POCD cannot be separated from the evaluation of perioperative cognitive function of patients, and the more popular and accepted method is neuropsychological tests (NPTs).

The international ENIGMA-II substudy on postoperative cognitive disorders (ISEP)

There is a large controversy as to whether nitrous oxide (N₂O) added to the anaesthetic gas mixture is harmful or harmless for postoperative cognitive function recovery. We performed a nested study in the ENIGMA-II trial and compared postoperative neurocognitive recovery of patients randomly receiving N₂O (70%) or Air (70%) in 30% O₂ during anesthesia. We included adults having non cardiac surgery. We compared recovery scores for episodic memory, decision making/processing speed and executive functions measured with the computerised Cambridge Neuropsychological Test Automated Battery (CANTAB). Assessments were performed at baseline, seven and ninety days. At first interim analysis, following recruitment of 140 participants, the trial was suspended. We found that the mean (95%CI) changes of scores for episodic memory were in the Pocock futility boundaries. Decision making/processing speed did not differ either between groups (P > 0.182). But for executive functions at seven days, the mean number (95% CI) of problems successfully solved and the number of correct box choices made was higher in the N2O group, P = 0.029. N₂O with the limitations of an interim analysis appears to have no harmful effect on cognitive functions (memory/processing speed). It may improve the early recovery process of executive functions. This preliminary finding warrants further investigations.

Outcome of Organ Dysfunction in the Perioperative Period

While intraoperative mortality has diminished greatly over the last several decades, the risk of death within 30 days of surgery remains stubbornly high and is ultimately related to perioperative organ failure. Perioperative strokes, while rare (<2% in noncardiac surgery), are associated with a more than 10-fold increase in mortality. Rapid identification and treatment are key to maximizing long-term outcomes. Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) are separate but related perioperative neurological disorders, both of which are associated with poor long-term outcomes. To date, there are few known interventions that can ameliorate the risk of perioperative central nervous system dysfunction. Major adverse cardiac events (MACE) are a major contributor to adverse clinical outcomes following surgical procedures. Recently, advances in diagnostic strategies (eg, high-sensitivity cardiac troponin [hs-cTn] assays) have improved our understanding of MACE. Recently, the dabigatran in patients with myocardial injury after noncardiac surgery (MINS; Management of myocardial injury After NoncArdiac surGEry) trial demonstrated that a direct thrombin inhibitor could improve outcomes following MINS. While the risk of acute respiratory distress syndrome (ARDS) after surgery is approximately 0.2%, other less severe complications (eg, pneumonia, reintubation) are closer to 2%. While intensive care unit (ICU) concepts related to ARDS have migrated into the operating room, whether or not adverse pulmonary outcomes impact long-term outcomes in surgical patients remains a matter of debate. The standardization of acute kidney injury (AKI) definition has improved the ability of clinicians to measure and study the incidence of this important source of perioperative morbidity. AKI is associated with increased mortality as well as nonrenal morbidity (eg, myocardial infarction) after major surgery. Gastrointestinal complications after surgery range from ileus (common in abdominal procedures and associated with an increased length of stay) to less common complications such as mesenteric ischemia and gastrointestinal bleeding, both of which are associated with very high mortality. Outside of cardiothoracic surgery, the incidence of perioperative hepatic injury is not well described but, in this population, is associated with worsened long-term outcomes. Hyperglycemia is a common perioperative complication and occurs in patients undergoing both cardiac and noncardiac surgery. Both hyper- and hypoglycemia are associated with worsened long-term outcomes in cardiac and noncardiac surgery. Better diagnosis and increased understanding of perioperative organ injury has led to an increased appreciation for the specific role that particular organ systems play in poor long-term outcomes and has set the stage for targeted therapeutic interventions.

Cerebral Hypoxia: Its Role in Age-Related Chronic and Acute Cognitive Dysfunction

Postoperative cognitive dysfunction (POCD) has been reported with widely varying frequency but appears to be strongly associated with aging. Outside of the surgical arena, chronic and acute cerebral hypoxia may exist as a result of respiratory, cardiovascular, or anemic conditions. Hypoxia has been extensively implicated in cognitive impairment. Furthermore, disease states associated with hypoxia both accompany and progress with aging. Perioperative cerebral hypoxia is likely underdiagnosed, and its contribution to POCD is underappreciated. Herein, we discuss the various disease processes and forms in which hypoxia may contribute to POCD. Furthermore, we outline hypoxia-related mechanisms, such as hypoxia-inducible factor activation, cerebral ischemia, cerebrovascular reserve, excitotoxicity, and neuroinflammation, which may contribute to cognitive impairment and how these mechanisms interact with aging. Finally, we discuss opportunities to prevent and manage POCD related to hypoxia.

Cognitive decline among older adults: A hidden preexisting condition and its role in 'brain-at-risk' surgical patients

Preexisting cognitive impairment is an important, but underrecognized, predictor of postoperative neurocognitive dysfunction, a common and important sequela of surgery. We have applied computerized neuropsychological testing as an efficient and reliable means of detecting preexisting cognitive impairment in two studies of cardiac and noncardiac surgical populations and propose that this tool has great potential in routine clinical diagnosis.

Anesthetic Consideration for Geriatric Patients

The geriatric population experiences significant alterations of numerous organ systems as a result of the aging process. They also have several co-morbidities including hypertension, cardiac disease, diabetes, cerebrovascular disease and renal dysfunction. Geriatric patients are considerably vulnerable and especially sensitive to the stress of trauma, surgery and anesthesia. A high incidence of postoperative complications in this population is observed. Appropriate perioperative care was required for geriatric patients. To date, development in anesthesia and surgical techniques has substantially reduced morbidity and mortality in the geriatric patients. Several anesthetic techniques have been utilized for these patients. However, anesthesia-related mortality in geriatric patients is quiet high. All geriatric patients undergoing surgical procedures require a preprocedural evaluation and preparation, monitoring patients during intraprocedural and postprocedural periods as well as postprocedural management. This chapter highlights the physiological changes, preprocedure assessment and preparation, anesthetic techniques, intraprocedural and postprocedural management in geriatric population.

Isoflurane affects brain functional connectivity in rats 1 month after exposure

Isoflurane, the most commonly used preclinical anesthetic, induces brain plasticity and long-term cellular and molecular changes leading to behavioral and/or cognitive consequences. These changes are most likely associated with network-level changes in brain function. To elucidate the mechanisms underlying long-term effects of isoflurane, we investigated the influence of a single isoflurane exposure on functional connectivity, brain electrical activity, and gene expression. Male Wistar rats (n = 22) were exposed to 1.8% isoflurane for 3 h. Control rats (n = 22) spent 3 h in the same room without exposure to anesthesia. After 1 month, functional connectivity was evaluated with resting-state functional magnetic resonance imaging (fMRI; n = 6 + 6) and local field potential measurements (n = 6 + 6) in anesthetized animals. A whole genome expression analysis (n = 10+10) was also conducted with mRNA-sequencing from cortical and hippocampal tissue samples. Isoflurane treatment strengthened thalamo-cortical and hippocampal-cortical functional connectivity. Cortical low-frequency fMRI power was also significantly increased in response to the isoflurane treatment. The local field potential results indicating strengthened hippocampal-cortical alpha and beta coherence were in good agreement with the fMRI findings. Furthermore, altered expression was found in 20 cortical genes, several of which are involved in neuronal signal transmission, but no gene expression changes were noted in the hippocampus. Isoflurane induced prolonged changes in thalamo-cortical and hippocampal-cortical function and expression of genes contributing to signal transmission in the cortex. Further studies are required to investigate whether these changes are associated with the postoperative behavioral and cognitive symptoms commonly observed in patients and animals.

Intravenous versus Volatile Anesthetic Effects on Postoperative Cognition in Elderly Patients Undergoing Laparoscopic Abdominal Surgery

BACKGROUND

Delayed neurocognitive recovery after surgery is associated with poor outcome. Most surgeries require general anesthesia, of which sevoflurane and propofol are the most commonly used inhalational and intravenous anesthetics. The authors tested the primary hypothesis that patients with laparoscopic abdominal surgery under propofol-based anesthesia have a lower incidence of delayed neurocognitive recovery than patients under sevoflurane-based anesthesia. A second hypothesis is that there were blood biomarkers for predicting delayed neurocognitive recovery to occur.

METHODS

A randomized, double-blind, parallel, controlled study was performed at four hospitals in China. Elderly patients (60 yr and older) undergoing laparoscopic abdominal surgery that was likely longer than 2 h were randomized to a propofol- or sevoflurane-based regimen to maintain general anesthesia. A minimum of 221 patients was planned for each group to detect a one-third decrease in delayed neurocognitive recovery incidence in propofol group compared with sevoflurane group. The primary outcome was delayed neurocognitive recovery incidence 5 to 7 days after surgery.

RESULTS

A total of 544 patients were enrolled, with 272 patients in each group. Of these patients, 226 in the propofol group and 221 in the sevoflurane group completed the needed neuropsychological tests for diagnosing delayed neurocognitive recovery, and 46 (20.8%) in the sevoflurane group and 38 (16.8%) in the propofol group met the criteria for delayed neurocognitive recovery (odds ratio, 0.77; 95% CI, 0.48 to 1.24; P = 0.279). A high blood interleukin-6 concentration at 1 h after skin incision was associated with an increased likelihood of delayed neurocognitive recovery (odds ratio, 1.04; 95% CI, 1.01 to 1.07; P = 0.007). Adverse event incidences were similar in both groups.

CONCLUSIONS

Anesthetic choice between propofol and sevoflurane did not appear to affect the incidence of delayed neurocognitive recovery 5 to 7 days after laparoscopic abdominal surgery. A high blood interleukin-6 concentration after surgical incision may be an independent risk factor for delayed neurocognitive recovery.

EDITOR’S PERSPECTIVE

[Effects of different postoperative analgesic strategies on postoperative neurocognitive function and quality of recovery in elderly patients undergoing one lung ventilation]

OBJECTIVE

To evaluate the effects of different postoperative analgesic strategies on neurocognitive function and quality of recovery in elderly patients at 7 days after thoracic surgery with one lung ventilation.

METHODS

Ninety elderly patients undergoing video-assisted thoracic surgery were randomized into 3 groups (n=30) to receive postoperative analgesia with thoracic paravertebral block analgesia (TA), epidural analgesia (EA) and intravenous analgesia (GA). Before and at 7 days after the surgery, the patients' cognitive function was assessed using Mini-Mental State Examination (MMSE), and their early recovery at 7 days postoperatively was evaluated using Quality of Recovery-40 items (QoR-40).

RESULTS

The patients in TA and EA groups had significantly higher MMSE scores and lower incidence of postoperative neurocognitive dysfunction (PNCD) than those in GA group without significant difference between the former two groups. At 7 days after the surgery, serum levels of S100-β and MMP-9 were significantly higher in GA group than in TA and EA group, and did not differ significantly between the latter two groups. QoR-40 scores were significantly higher in TA and EA groups than in GA group, and were higher in TA group than in EA group. The chest intubation time and length of hospital stay were significantly shorter in TA and EA groups than in GA group.

CONCLUSIONS

In elderly patients undergoing surgeries with one lung ventilation, general anesthesia combined with either postoperative continuous thoracic paravertebral block or epidural analgesia can significantly improve postoperative neurocognitive function and quality of recovery, but continuous thoracic paravertebral block analgesia can be more advantageous for improving postoperative quality of recovery.

Major Surgery Affects Memory in Individuals with Cerebral Amyloid-β Pathology

BACKGROUND

Major surgery has been associated with perioperative neurocognitive disorders (PND), but the contributing factors and long-term prognosis are uncertain. We hypothesize that preclinical Alzheimer's disease (AD) might predispose to cognitive deterioration after surgery.

OBJECTIVE

To analyze the effect of amyloid-β on the cognitive trajectory after orthopedic surgery in a sample of non-demented subjects.

METHODS

Non-demented individuals older than 65 years that were on the waiting list for orthopedic surgery with spinal anesthesia underwent a neuropsychological assessment before and after surgery. During surgery, cerebrospinal fluid samples were obtained to determine AD biomarkers.

RESULTS

Cumulative incidence of PND was 55.2%during a mean follow-up of nine months. The most affected cognitive domains were executive function and constructional praxis. The presence of abnormal levels of amyloid-β was associated to a postoperative impairment in verbal and visual memory tests. According to their AD biomarker profile, participants were categorized as either Amyloid Positive (A+) or Amyloid Negative (A-). The incidence of PND did not differ between both groups. The A- group showed a tendency similar to the global sample, worsening in executive function tests and improving on memory scales due to practice effects. In contrast, the A + group showed a notable worsening on memory performance.

CONCLUSION

Our findings support the hypothesis that surgery may promote or accelerate memory decline in cognitively asymptomatic subjects with brain amyloid-β deposits.