Anesthesiology and cognitive impairment: a narrative review of current clinical literature

The propofol-induced mitochondrial damage in fetal rat hippocampal neurons via the AMPK/P53 signaling pathway

BACKGROUND

Propofol is a commonly used general anesthetic that may cause neuronal damage, especially in infants and young children. Mitochondria play an essential role in cellular metabolism and signal transduction. Propofol may cause neurotoxicity by inhibiting mitochondrial function, but the mechanism by this which occurs remains unclear.

METHODS

First, the primary rat hippocampal neurons were cultured for 7 days in vitro. The neurons were incubated with propofol at different times or different concentrations, and then the adenosine triphosphate (ATP), reactive oxygen species (ROS), mitochondrial membrane potential, and apoptosis-related proteins were analyzed. Based on the results of the 1st phase, the neurons were then incubated with propofol (100 µM) or corresponding reagents, including 5-aminoimidazole-4-carboxamide ribonucleotide, tenovin-1, and pifithrin-α. Subsequently, the ATP, ROS, mitochondrial membrane potential, phospho-adenosine 5'-monophosphate-activated protein kinase (p-AMPK), protein 53 (p53), and related apoptosis proteins were analyzed.

RESULTS

Higher propofol concentrations or longer incubation times were associated with more pronounced decreases in ATP, B-cell lymphoma 2 (Bcl-2), and mitochondrial membrane potential, and more pronounced increases in ROS, BCL2-associated X (Bax), Cytochrome C (CytC), and cleaved caspase-9. Additionally, after incubation with propofol (100 µM), neuronal Bcl-2, p-AMPK, ATP, and mitochondrial membrane potential were downregulated, and ROS, p53, CytC, Bax, cleaved caspase-3, and cleaved caspase-9 were upregulated. AMPK activators or p53 inhibitors reversed the above-mentioned changes.

CONCLUSIONS

Propofol (100 µM)-induced mitochondrial damage in fetal rat hippocampal neurons may be mediated by the AMPK/p53 signaling pathway. Propofol (100 µM) was shown to inhibit the activity of AMPK in neurons, upregulate the expression of p53, and then activate the mitochondrial-dependent apoptosis pathway, which may lead to neuronal apoptosis.

Persistent Depletion of Neuroprotective Factors Accompanies Neuroinflammatory, Neurodegenerative, and Vascular Remodeling Spectra in Serum Three Months after Non-Emergent Cardiac Surgery

We hypothesized that the persistent depletion of neuroprotective markers accompanies neuroinflammation and neurodegeneration in patients after cardiac surgery. A total of 158 patients underwent elective heart surgery with their blood collected before surgery (t_baseline) and 24 h (t_24hr), seven days (t_7d), and three months (t_3m) post-surgery. The patients’ serum was measured for markers of neurodegeneration (τau, τaup181–183, amyloid β1-40/β2-42, and S100), atypical neurodegeneration (KLK6 and NRGN), neuro-injury (neurofilament light/heavy, UC-HL, and GFAP), neuroinflammation (YKL-40 and TDP-43), peripheral nerve damage (NCAM-1), neuroprotection (apoE4, BDNF, fetuin, and clusterin), and vascular smoldering inflammation (C-reactive protein, CCL-28 IL-6, and IL-8). The mortality at 28 days, incidence of cerebrovascular accidents (CVA), and functional status were followed for three months. The levels of amyloid β1-40/β1-42 and NF-L were significantly elevated at all time points. The levels of τau, S100, KLK6, NRGN, and NCAM-1 were significantly elevated at 24 h. A cluster analysis demonstrated groupings around amyloids, KLK6, and NCAM-1. YKL-40, but not TDP-43, was significantly elevated across all time points. BDNF, apoE4, fetuin, and clusterin levels were significantly diminished long-term. IL-6 and IL-8 levles returned to baseline at t_3m. The levels of CRP, CCL-28, and Hsp-70 remained elevated. At 3 months, 8.2% of the patients experienced a stroke, with transfusion volume being a significant variable. Cardiac-surgery patients exhibited persistent peripheral and neuronal inflammation, blood vessel remodeling, and the depletion of neuroprotective factors 3 months post-procedure.

Recent Updates on Risk and Management Plans Associated with Polypharmacy in Older Population

The concept of polypharmacy encompasses adverse drug reactions and non-adherence factors in elderly individuals. It also leads to the increased use of healthcare services and negative health outcomes. The problem is further alleviated by the odds of potentially inappropriate medications (PIM), which lead to the development of drug-related problems. Since polypharmacy is more commonly observed in the elderly population, urgency is required to introduce operative protocols for preventing and managing this problem. The family medicine model of care can be associated with favorable illness outcomes regarding satisfaction with consultation, treatment adherence, self-management behaviors, adherence to medical advice, and healthcare utilization. Hence, interventions built on family medicine models can provide significant support in improving the outcomes of the older population and their quality of life. In this regard, the authors have taken up the task of explaining the accessible resources which can be availed to improve the application of health care services in the field of geriatric medicine.

Young plasma reverses anesthesia and surgery-induced cognitive impairment in aged rats by modulating hippocampal synaptic plasticity

We investigated the protective effect of young plasma on anesthesia- and surgery-induced cognitive impairment and the potential underlying mechanism using bioinformatics, functional enrichment analysis, gene set enrichment analysis, Golgi-Cox staining, dendritic spine analysis, immunofluorescence assay, western blot analysis, and transmission electron microscopy. Furthermore, we performed behavioral assessments using the open field test, the novel object recognition test, and the Morris water maze test. We identified 1969 differentially expressed genes induced by young plasma treatment, including 800 upregulated genes and 1169 downregulated genes, highlighting several enriched biological processes (signal release from synapse, postsynaptic density and neuron to neuron synapse). Anesthesia- and surgery-induced cognitive impairment in aged rats was comparatively less severe following young plasma preinfusion. In addition, the decreased levels of synapse-related and tyrosine kinase B/extracellular signal-regulated protein kinase/cyclic adenosine monophosphate response element-binding protein (TrkB/ERK/CREB) signaling pathway-related proteins, dendritic and spine deficits, and ultrastructural changes were ameliorated in aged mice following young plasma preinfusion. Together, these findings suggest that young plasma reverses anesthesia- and surgery-induced cognitive impairment in aged rats and that the mechanism is associated with the activation of the TrkB/ERK/CREB signaling pathway and improvement in hippocampal synaptic plasticity.

The Mechanism of TNF-α-Mediated Accumulation of Phosphorylated Tau Protein and Its Modulation by Propofol in Primary Mouse Hippocampal Neurons: Role of Mitophagy, NLRP3, and p62/Keap1/Nrf2 Pathway

Background

Neuroinflammation-induced phosphorylated Tau (p-Tau) deposition in central nervous system contributes to neurodegenerative disorders. Propofol possesses neuroprotective properties. We investigated its impacts on tumor necrosis factor-α (TNF-α)-mediated p-Tau deposition in neurons.

Methods

Mouse hippocampal neurons were exposed to propofol followed by TNF-α. Cell viability, p-Tau, mitophagy, reactive oxygen species (ROS), NOD-like receptor protein 3 (NLRP3), antioxidant enzymes, and p62/Keap1/Nrf2 pathway were investigated.

Results

TNF-α promoted p-Tau accumulation in a concentration- and time-dependent manner. TNF-α (20 ng/mL, 4 h) inhibited mitophagy while increased ROS accumulation and NLRP3 activation. It also induced glycogen synthase kinase-3β (GSK3β) while inhibited protein phosphatase 2A (PP2A) phosphorylation. All these effects were attenuated by 25 μM propofol. In addition, TNF-α-induced p-Tau accumulation was attenuated by ROS scavenger, NLRP3 inhibitor, GSK3β inhibitor, or PP2A activator. Besides, compared with control neurons, 100 μM propofol decreased p-Tau accumulation. It also decreased ROS and NLRP3 activation, modulated GSK3β/PP2A phosphorylation, leaving mitophagy unchanged. Further, 100 μM propofol induced p62 expression, reduced Keap1 expression, triggered the nuclear translocation of Nrf2, and upregulated superoxide dismutase (SOD) and heme oxygenase-1 (HO-1) expression, which was abolished by p62 knockdown, Keap1 overexpression, or Nrf2 inhibitor. Consistently, the inhibitory effect of 100 μM propofol on ROS and p-Tau accumulation was mitigated by p62 knockdown, Keap1 overexpression, or Nrf2 inhibitor.

Conclusions

In hippocampal neurons, TNF-α inhibited mitophagy, caused oxidative stress and NLRP3 activation, leading to GSK3β/PP2A-dependent Tau phosphorylation. Propofol may reduce p-Tau accumulation by reversing mitophagy and oxidative stress-related events. Besides, propofol may reduce p-Tau accumulation by modulating SOD and HO-1 expression through p62/Keap1/Nrf2 pathway.

Association of markers of tumor aggressivity and cognition in women with breast cancer before adjuvant treatment: The Thinking and Living with Cancer Study

PURPOSE

Tumor features associated with aggressive cancers may affect cognition prior to systemic therapy. We evaluated associations of cognition prior to adjuvant therapy and tumor aggressivity in older breast cancer patients.

METHODS

Women diagnosed with non-metastatic breast cancer (n = 705) ages 60-98 were enrolled from August 2010-March 2020. Cognition was measured post-surgery, pre-systemic therapy using self-reported (FACT-Cog Perceived Cognitive Impairment [PCI]) and objective tests of attention, processing speed, and executive function (APE domain) and learning and memory [LM domain]. Linear regression tested associations of pre-treatment tumor features and cognition, adjusting for age, race, and study site. HER2 positivity and higher stage (II/III vs. 0/I) were a priori predictors of cognition; in secondary analyses we explored associations of other tumor features and cognitive impairment (i.e., PCI score < 54 or having 2 tests < 1.5 SD or 1 test < 2 SD from the mean APE or LM domain score).

RESULTS

HER2 positivity and the hormone receptor negative/HER2 + molecular subtype were associated with lower adjusted mean self-reported cognition scores and higher impairment rates (p values < .05). Higher stage of disease was associated with lower objective performance in APE. Other tumor features were associated with cognition in unadjusted and adjusted models, including larger tumor size and lower PCI scores (p = 0.02). Tumor features were not related to LM.

CONCLUSIONS

Pre-adjuvant therapy cognition was associated with HER2 positivity and higher stage of disease and other features of aggressive tumors. Additional research is needed to confirm these results and assess potential mechanisms and clinical management strategies.

Perioperative outcomes of general versus spinal anesthesia in the lumbar spine surgery population: A systematic review and meta-analysis of data from 2005 through 2021

STUDY DESIGN

Meta-analysis.

OBJECTIVES

Perform a systematic review and meta-analysis to determine the perioperative utility of general versus spinal anesthesia in the lumbar spine surgery population.

METHODS

PubMed and Embase were queried for manuscripts reporting perioperative outcomes for patients undergoing one to three-level lumbar spine surgery (including decompression, fusion, and decompression with fusion) using either general or spinal anesthesia. Inclusion criteria included studies published from 2005 to 2021, in English, involving primary data from human subjects. Studies were further screened for data on total operative time, blood loss, intraoperative hypotension, pain scores, postoperative nausea and vomiting, time required in post-anesthesia care unit (PACU), PACU pain anesthetic requirement, and length of stay. Risk of bias for each study was assessed using standardized tools (i.e., RoB 2, ROBINS-I, NOS, as appropriate). Potential predictors of outcome were compared using univariate analysis, and variables potentially associated with outcome were subjected to meta-analysis using Cochran-Mantel-Haenszel testing to produce standard mean differences (SMD) or odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

In total, 12 studies totaling 2796 patients met inclusion criteria. 1414 (50.6%) and 1382 (49.4%) patients underwent lumbar spine surgery with general anesthesia and spinal anesthesia, respectively. Patients undergoing spinal anesthesia were statistically more likely to have coronary artery disease and respiratory dysfunction. Total operative time (SMD: 12.62 min, 95% CI -18.65 to -6.59), estimated blood loss (SMD: 0.57 mL, 95% CI -0.68 to -0.46), postoperative nausea and vomiting (OR = 0.20, 95% CI 0.15 to 0.26), time required in PACU (SMD = -0.20 min, 95% CI -0.32 to -0.08), and length of stay (SMD = -0.14 day, 95% CI -0.18 to -0.10), all statistically significantly favored spinal anesthesia over general anesthesia (p < 0.05).

CONCLUSION

In one to three-level lumbar spine surgery, current literature supports spinal anesthesia as a viable alternative to general anesthesia. As this was a heterogeneous patient population, prospective randomized trials are needed to corroborate findings.

Screening for Mild Cognitive Impairment in the Preoperative Setting: A Narrative Review

Cognitive impairment predisposes patients to the development of delirium and postoperative cognitive dysfunction. In particular, in older patients, the adverse sequelae of cognitive decline in the perioperative period may contribute to adverse outcomes after surgical procedures. Subtle signs of cognitive impairment are often not previously diagnosed. Therefore, the aim of this review is to describe the available cognitive screeners suitable for preoperative screening and their psychometric properties for identifying mild cognitive impairment, as preoperative workup may improve perioperative care for patients at risk for postoperative cognitive dysfunction. Electronic systematic and snowball searches of PubMed, PsycInfo, ClinicalKey, and ScienceDirect were conducted for the period 2015–2020. Major inclusion criteria for articles included those that discussed a screener that included the cognitive domain ‘memory’, that had a duration time of less than 15 min, and that reported sensitivity and specificity to detect mild cognitive impairment. Studies about informant-based screeners were excluded. We provided an overview of the characteristics of the cognitive screener, such as interrater and test-retest reliability correlations, sensitivity and specificity for mild cognitive impairment and cognitive impairment, and duration of the screener and cutoff points. Of the 4775 identified titles, 3222 were excluded from further analysis because they were published prior to 2015. One thousand four hundred and forty-eight titles did not fulfill the inclusion criteria. All abstracts of 52 studies on 45 screeners were examined of which 10 met the inclusion criteria. For these 10 screeners, a further snowball search was performed to obtain related studies, resulting in 20 articles. Screeners included in this review were the Mini-Cog, MoCA, O3DY, AD8, SAGE, SLUMS, TICS(-M), QMCI, MMSE2, and Mini-ACE. The sensitivity and specificity range to detect MCI in an older population is the highest for the MoCA, with a sensitivity range of 81–93% and a specificity range of 74–89%. The MoCA, with the highest combination of sensitivity and specificity, is a feasible and valid routine screening of pre-surgical cognitive function. This warrants further implementation and validation studies in surgical pathways with a large proportion of older patients.

MiR-128-3p Attenuates the Neurotoxicity in Rats Induced by Isoflurane Anesthesia

Isoflurane (ISO) has been widely used in clinical anesthesia, and exposure to ISO leads to cognitive dysfunction. Our paper aimed to investigate the effect of miR-128-3p on cognitive impairment, inflammation, and oxidative stress elicited by ISO anesthesia in Sprague-Dawley (SD) rats. The SD rats were treated with ISO to mimic the ISO-injured situation, and the concentration of miR-128-3p was quantified utilizing real-time PCR. The miR-128-3p's impacts in ISO-engendered rat models on the respects of inflammatory condition and oxidative activities were measured by the commercial kits. The Morris water maze test was adopted to measure the neuro-function regarding miR-128-3p. Additionally, the target was tested by the alternation of luciferase activity. The irritation of ISO suppressed miR-128-3p expression in rats, which was enhanced by the injection of miR-128-3p agomir. The adverse roles of ISO on inflammation, oxidative stress, and cognitive disorders were partially abrogated by an increment of miR-128-3p. A miR-128-3p's interconnection with specificity protein 1 (SP1) was pinpointed, and aggrandized mRNA levels of SP1 were found under ISO state. MiR-128 acted as a regulator in ISO damage in the respects of cognition, inflammation, and oxidative stress. The SP1's link of miR-128-3p was showcased.

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.

Dexmedetomidine reduces propofol-induced hippocampal neuron injury by modulating the miR-377-5p/Arc pathway

BACKGROUND

Propofol and dexmedetomidine (DEX) are widely used in general anesthesia, and exert toxic and protective effects on hippocampal neurons, respectively. The study sought to investigate the molecular mechanisms of DEX-mediated neuroprotection against propofol-induced hippocampal neuron injury in mouse brains.

METHODS

Hippocampal neurons of mice and HT22 cells were treated with propofol, DEX, and propofol+DEX. In addition, transfection of miR-377-5p mimics or inhibitors was performed in HT22 cells. Neuronal apoptosis was evaluated by a means of terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) or Hochest 33,258 staining; Arc positive expression in hippocampus tissues was detected using a microscope in immunohistochemistry assays; miRNA-377-5p expression was quantified by RT-qPCR; the protein levels of Arc, DNMT3A, and DNMT3B were determined using western blot; Cell Counting Kit-8 (CCK-8) assay was used to detect the viability and apoptotic rate of the neurons; methylation analysis in the miR-377-5p promoter was performed through methylated DNA immunoprecipitation (MeDIP) assay; dual luciferase reporter assay was performed to confirm whether Arc was under targeted regulation of miR-377-5p.

RESULTS

In the current study, both in vitro and in vivo, propofol treatment induced hippocampal neuron apoptosis and suppressed cell viability. DNMT3A and DNMT3B expression levels were decreased following propofol treatment, resulting in lowered methylation in the miR-377-5p promoter region and then enhanced expression of miR-377-5p, leading to a decrease in the expression of downstream Arc. Conversely, the expression levels of DNMT3A and DNMT3B were increased following DEX treatment, thus methylation in miR-377-5p promoter region was improved, and miR-377-5p expression was decreased, leading to an increase in the expression of downstream Arc. Eventually, DEX pretreatment protected hippocampal neurons against propofol-induced neurotoxicity by recovering the expression levels of DNMT3A, miR-377-5p, and Arc to the normal levels. Additionally, DNMT3A knockdown improved miR-377-5p expression but reduced Arc expression, and DNMT3A overexpression exerted the opposite effects. Dual luciferase reporter assay revealed a binding target between miR-377-5p and Arc 3'UTR. The neuroprotective effect of DEX against propofol-induced neuronal apoptosis was diminished after Arc knockdown. Silencing Arc independently triggered the apoptosis of HT22 cells, which was alleviated through transfection of miR-377-5p inhibitors.

CONCLUSIONS

DEX reduced propofol-induced hippocampal neuron injury via the miR-377-5p/Arc signaling pathway.

Navigation strategies in patients with vestibular loss tested in a virtual reality T-maze

During navigation, humans mainly rely on egocentric and allocentric spatial strategies, two different frames of reference working together to build a coherent representation of the environment. Spatial memory deficits during navigation have been repeatedly reported in patients with vestibular disorders. However, little is known about how vestibular disorders can change the use of spatial navigation strategies. Here, we used a new reverse T-maze paradigm in virtual reality to explore whether vestibular loss specifically modifies the use of egocentric or allocentric spatial strategies in patients with unilateral (n = 23) and bilateral (n = 23) vestibular loss compared to healthy volunteers (n = 23) matched for age, sex and education level. Results showed that the odds of selecting and using a specific strategy in the T-maze were significantly reduced in both unilateral and bilateral vestibular loss. An exploratory analysis suggests that only right vestibular loss decreased the odds of adopting a spatial strategy, indicating an asymmetry of vestibular functions. When considering patients who used strategies to navigate, we observed that a bilateral vestibular loss reduced the odds to use an allocentric strategy, whereas a unilateral vestibular loss decreased the odds to use an egocentric strategy. Age was significantly associated with an overall lower chance to adopt a navigation strategy and, more specifically, with a decrease in the odds of using an allocentric strategy. We did not observe any sex difference in the ability to select and use a specific navigation strategy. Findings are discussed in light of previous studies on visuo-spatial abilities and studies of vestibulo-hippocampal interactions in peripheral vestibular disorders. We discuss the potential impact of the history of the disease (chronic stage in patients with a bilateral vestibulopathy vs. subacute stage in patients with a unilateral vestibular loss), of hearing impairment and non-specific attentional deficits in patients with vestibular disorders.

Application of different doses of fentanyl combined with ketorolac tromethamine for painless gastroscopy in elderly obese patients

BACKGROUND

Painless gastroscopy is carried out under general anesthesia, with advantages of painlessness, short time, and safety. Advanced analgesia has been advocated in recent years, and analgesia program, such as ketorolac ammonia buttriol, has a strong analgesic effect, can reduce the central sensitization caused by the introduction of harmful stimulus, and relieve acute and chronic pain, which is especially suitable for perioperative analgesia.

AIM

To investigate the efficacy of different doses of sufentanil combined with ketorolac tromethamine for painless gastroscopy in elderly obese patients and its influence on neurocognitive disorders.

METHODS

A total of 163 elderly obese who would undergo painless gastroscopy at our hospital from March 2019 to March 2021 were randomly divided into group A (n = 55), group B (n = 54), and group C (n = 54), and they were given low-dose sufentanil + ketorolac tromethamine, medium-dose sufentanil + ketorolac tromethamine, and high-dose sufentanil + ketorolac tromethamine, respectively. Vital signs [mean arterial pressure (MAP) and heart rate (HR)], Ramsay sedation score, visual analog scale (VAS) score, mini-mental state examination (MMSE) score, anesthesia-related indicators (anesthesia onset time, painless gastroscopy, recovery time, and anesthesia recovery time), satisfaction, and adverse reactions were compared among the three groups.

RESULTS

At the time of inserting gastroscope (T2) and the time of gastroscope entering the opening of the duodenal papilla (T3), the MAP in group A was lower than that of groups B and C, and HR was higher than that of groups B and C (P < 0.05); there was no statistical difference in MAP or HR between groups B and C at T2 and T3. The BIS value of group A was lower than those of group B and group C (P < 0.05); there was no statistically significant difference in the BIS value between group B and group C during the examination (P > 0.05). The VAS score of group A after waking up was higher than those of group B and group C (P < 0.05); there was no statistically significant difference in VAS score between group B and group C after waking up (P > 0.05). The MMSE scores in groups A and B after waking up were higher than that of group C (P < 0.05); there was no statistically significant difference in MMSE score between group A and group B (P > 0.05). Anesthesia onset time, painless gastroscopy, awakening time, and anesthesia recovery time were shorter in group B than in group A and group C (P < 0.05). The incidence of severe apnea events in group A and group B were lower than that of group C (P < 0.05).

CONCLUSION

Sufentanil 0.15 μg/kg combined with ketorolac tromethamine can stabilize vital signs, relieve pain, reduce severe apnea events, shorten anesthesia recovery time, and be effective in painless gastrointestinal endoscopy in elderly obese patients, with minimal impact on neurocognitive disorders.

Polypharmacy in Older Adults Undergoing Major Surgery: Prevalence, Association With Postoperative Cognitive Dysfunction and Potential Associated Anesthetic Agents

BACKGROUND

Polypharmacy, which is defined as the use of 5 or more medications, can exert significant adverse impact on older adult patients. The objective of this study was to determine the prevalence of polypharmacy, and to investigate its association with postoperative cognitive dysfunction (POCD) in older adult patients who underwent elective major surgery at Siriraj Hospital-Thailand's largest national tertiary referral center.

METHODS

This prospective study included older adult patients aged ≥65 years who were scheduled for elective major surgery during December, 2017 to December, 2019 study period. Patient demographic, sociodemographic, anthropometric, clinical, comorbidity, anesthetic, surgical, and medication data were collected and compared between the polypharmacy and non-polypharmacy groups. Postoperative cognitive dysfunction (POCD) was diagnosed in patients with at least a 2-point decrease in their Montreal Cognitive Assessment score after surgery. Multivariate logistic regression analysis was used to identify independent predictors of POCD.

RESULTS

A total of 250 patients (141 males, 109 females) with an average age of 72.88 ± 6.93 years were included. The prevalence of polypharmacy was 74%. Preoperative data showed the polypharmacy group to be more likely to be receiving potentially inappropriate medications, to be scheduled for cardiovascular thoracic surgery, and to have more comorbidities. There was a non-significant trend in the association of polypharmacy and POCD (crude odds ratio (OR): 2.11, 95% confidence interval [CI]: 0.90-4.94; p = 0.08). Benzodiazepine, desflurane, or isoflurane administration during surgery were all significantly associated with POCD in univariate analysis. Multivariate analysis revealed intraoperative benzodiazepine (adjusted OR [aOR]: 2.24, 95% CI: 1.10-4.68; p = 0.026) and isoflurane (aOR: 2.80, 95% CI: 1.35-5.81; p = 0.006) as two independent variables associated with the development of POCD. Desflurane was found to be a protective factor for POCD with a crude OR of 0.17 (95% CI: 0.03-0.74, p = 0.019); however, independent association was not found in multivariate analysis.

CONCLUSION

There was a high prevalence of polypharmacy in this study; however, although close (p = 0.08), significant association was not found between polypharmacy and POCD. Benzodiazepine and isoflurane were both identified as independent predictors of the development of POCD among older adult patients undergoing elective major surgery, especially among those classified as polypharmacy.

Spine Surgery Under Spinal vs General Anesthesia: Prospective Analysis of Quality of Life, Fatigue, and Cognition

BACKGROUND

There has recently been increasing interest in the use of spinal anesthesia (SA) for spine surgery. The literature that compared spine surgery under SA vs general anesthesia (GA) focused on safety, perioperative outcomes, and costs.

OBJECTIVE

To test if SA is associated with less postoperative fatigue, cognitive dysfunction, and better quality of life in patients undergoing lumbar spine surgery compared with GA.

METHODS

We conducted a prospective nonrandomized study in patients undergoing elective lumbar spine surgery under SA or GA by a single surgeon. Fatigue was assessed with the fatigue visual analog scale scale (0-10) and Chalder Fatigue Scale, quality of life with Medical Outcomes Study 12-item Short Form (SF-12), and differences in cognition with Mini-Mental State Examination. Patients were baselined before surgery and assessed again 1 mo after surgery.

RESULTS

Fifty patients completed the study, 25 underwent surgery under SA and 25 under GA. The groups were homogeneous for baseline clinical characteristics, with no differences in preoperative fatigue, quality of life, and cognition. At 1 mo after surgery, SA compared with GA had better fatigue scores: fatigue visual analog scale (2.9 ± 1.5 vs 5.9 ± 2.3 [P < .0001]) and Chalder Fatigue Scale (11.2 ± 3.1 vs 16.9 ± 3.9 [P < .0001]). One month postoperatively, we observed a significant difference in the SF-12 physical component, with SA having 38.8 ± 8.9 vs 29.4 ± 10.3 (P = .002). We did not observe significant postoperative differences in the SF-12 mental component or Mini-Mental State Examination.

CONCLUSION

Our study demonstrates that SA offers unique patient-centered advantages to GA for elective spine surgery. One month after surgery, patients who received SA had less postoperative fatigue and better quality of life.

Awake Plastic Surgery Procedures: The Use of a Sufentanil Sublingual Tablet to Improve Patient Experience

Background

Awake plastic surgery performed under minimal sedation has advantages including patient preference, affordability, and easier recovery compared to when performed under deeper sedation. Commonly used oral analgesics may not be adequate for awake procedures resulting in moderate to severe pain. Sufentanil sublingual tablet (SST) 30 mcg has been shown to provide timely analgesia with a safety profile appropriate for minimal-sedation settings.

Objectives

To examine perioperative outcomes in patients who underwent awake plastic surgery with local anesthesia and SST 30 mcg for pain control.

Methods

This study was a prospective single-group cohort study conducted at a single plastic surgery center. SST 30 mcg was administered approximately 30 minutes prior to the procedure. Outcome measures included the number of patients with adverse events, the number of patients requiring medications in the post-anesthesia care unit (PACU), and recovery time.

Results

Among the 31 patients, the most common procedures were liposuction (71%), facelift (10%), and blepharoplasty (6%). The mean (± standard error [SE]) procedural duration was 81 ± 9 minutes. No vital sign instability or oxygen desaturation was observed. Three patients (10%) experienced nausea, only one of which required treatment with oral ondansetron 4 mg in the PACU. One patient (3%) experienced dizziness that did not require treatment. No patients required opioids or other analgesics in the PACU for pain. The mean (±SE) recovery time was 15 ± 4 minutes.

Conclusions

Awake plastic surgery can be performed using SST 30 mcg with minimal side effects and a rapid recovery time.

Level of Evidence: 4

Does Preoperative Cognitive Optimization Improve Postoperative Outcomes in the Elderly?

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

Propofol alleviates postoperative cognitive dysfunction by inhibiting inflammation via up-regulating miR-223-3p in aged rats

OBJECTIVE

Postoperative cognitive dysfunction (POCD) affects 15-25% of surgical patients and causes significant morbidity and mortality. This study aims to investigate the mechanism of propofol reducing POCD in aged rats.

METHOD

Rats in Operate group and Propofol group were anesthetized with isoflurane and propofol, respectively, and then underwent cardiac surgery. Rats in Antagomir group were anesthetized with propofol and underwent cardiac surgery with preoperative injection of miR-223-3p antagomir. Barnes maze and Morris water maze (MWM) were used to test spatial learning and memory of rats. Immunofluorescence was used to detect the level of microglial cell marker IBA1. In addition, qRT-PCR was performed to measure the expression of miR-223-3p and inflammatory factors TNF-α, IL-1β and IL-6. Western blotting was conducted to detect the protein expression of Foxo1, TNF-α, IL-1β and IL-6.

RESULT

Isoflurane-anesthetized rats undergoing cardiac surgery showed significantly reduced spatial learning and memory, promoted microglia activation, decreased miR-223-3p expression and increased inflammatory response in the hippocampus, while isoflurane-anesthetized rats without surgery showed insignificant changes in these indices. Compared to isoflurane anesthesia, propofol anesthesia exhibited less effect on spatial learning and memory of rats with cardiac surgery and contributed to a relative reduction in activated microglia in the hippocampus, a notable increase in miR-223-3p expression, and a decrease in inflammation. The results were reversed after miR-223-3p antagomir was injected into propofol-anesthetized surgical rats. miR-223-3p negatively regulated Foxo1 to suppress the expression of inflammatory factors.

CONCLUSION

Propofol reduced inflammation by up-regulating miR-223-3p, thereby reducing POCD in aged rats.

Mirtazapine prevents cell activation, inflammation, and oxidative stress against isoflurane exposure in microglia

Mirtazapine is an antidepressant drug that has been proven to possess a cognitive enhancer efficiency. In this study, we evaluated the potential protective effects of mirtazapine on BV2 microglia in response to isoflurane exposure. Our results show that mirtazapine attenuated isoflurane-induced expression of microglia-specific protein Iba1 in BV2 microglia. Mirtazapine prevented isoflurane-induced production of the pro-inflammatory factors interleukin (IL)-1β and IL-18 by inhibiting the activation of the nod-like receptor family protein 3 (NLRP3) inflammasome in BV2 microglia. The increased reactive oxygen species (ROS) production and elevated expression level of NADPH oxidase 4 (NOX4) in isoflurane-induced BV2 microglia were mitigated by mirtazapine. Isoflurane exposure reduced triggering receptor expressed on myeloid cells 2 (TREM2) expression in BV2 microglia, which was restored by mirtazapine. Moreover, silencing of TREM2 abolished the inhibitory effects of mirtazapine on ionized calcium-binding adapter molecule 1 (Iba1) expression and inflammation in BV2 microglia. From these results, we could infer that mirtazapine exerted a protective effect on BV2 microglia against isoflurane exposure-caused microglia activation, neuroinflammation, and oxidative stress via inducing TREM2 activation. Hence, mirtazapine might be a potential intervention strategy to prevent isoflurane exposure-caused cognitive dysfunction in clinical practice.

Catalpol Alleviates Isoflurane-Induced Hippocampal Learning and Memory Dysfunction and Neuropathological Changes in Aged Mice

INTRODUCTION

Isoflurane-associated perioperative neurocognitive disorders (PNDs) is a common complication that occurs commonly in elderly patients characterized by deterioration of hippocampus-dependent cognitive function. Mounting evidence has shown that hippocampal impairment and inflammatory processes are implicated in the pathogenesis of PNDs. Catalpol has been suggested to play a role in the modulation of neuroprotection and neurotransmission. Therefore, we surmised that catalpol may play a similar role during isoflurane-induced PNDs.

METHODS

In our current study, aged mice were exposed to isoflurane to develop a mouse model of PNDs and preconditioned with catalpol for 2 weeks before modeling. Three weeks after isoflurane exposure, behavioral, histological, biochemical, electrophysiological, and immunofluorescent assays were performed.

RESULTS

Our results showed that catalpol preadministration significantly alleviated cognitive impairment in the Morris water maze, novel object recognition, and Y-maze behavioral tests. Neuropathological analyses showed that catalpol preadministration reduced the loss of neurons and synapses; in line with this, it is revealed that hippocampal synaptic plasticity was restored. Mechanistically, catalpol preadministration suppressed the activation of microglia and decreased the expression of NLRP3 inflammasome.

CONCLUSION

Our results indicate that catalpol preadministration could effectively alleviate cognitive impairment and neuropathological damage in isoflurane-exposed aged mice with its neuroprotective effects via modulation of the NLRP3 inflammatory pathway. Furthermore, the NLRP3 inflammatory pathway was revealed to be involved in these effects.

Role of Different Doses of Ketamine in Postoperative Neurocognitive Function in Aged Mice Undergoing Partial Hepatectomy by Regulating the Bmal1/NMDA/NF-Κb Axis

BACKGROUND

The current study set out to probe the function of different doses of ketamine in postoperative neurocognitive disorder (PND) in aged mice undergoing partial hepatectomy (PH) with the involvement of the brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein 1 (Bmal1)/n-methyl-D-aspartate (NMDA)/nuclear factor-kappa B (NF-κB) axis.

METHODS

First, aged mice were intraperitoneally injected with different doses of ketamine prior to surgery, followed by hepatic lobectomy. Afterward, mice cognitive function was assessed. In addition, Bmal1 mRNA expression patterns were quantified, while NMDA 2B receptor, NF-κB p65, synapsin 1, and postsynaptic density 95 (PSD95) levels were determined; the release of inflammatory factors was detected, and ionized calcium-binding adapter molecule-1 expression was measured to quantify microglia activation. In addition, Bmal1-knockout (Bmal1-KO) mice were intraperitoneally injected with a subanesthetic dose of ketamine to verify the mechanism of Bmal1 in regulating the NMDA 2B subunit (NR2B)/NF-κB axis to affect PH in aged patients.

RESULTS

After PH, hippocampal-dependent memory was impaired, and synapsin 1 and PSD95 levels were downregulated. On the other hand, PH diminished Bmal1 expression but elevated NR2B and NF-κB p65 levels and anesthetic doses of ketamine further regulated the Bmal1/NMDA/NF-κB axis. In Bmal1-KO mice, the NMDA/NF-κB axis was activated, the release of inflammatory cytokines was promoted, and hippocampus-dependent memory was impaired, which were reversed by a subanesthetic dose of ketamine.

CONCLUSION

Altogether, findings obtained in our study indicated that a subanesthetic dose of ketamine activated Bmal1, downregulated the NMDA/NF-κB axis, and reduced inflammation and microglia activation to alleviate PND in aged mice undergoing PH.

Age-related differences in cognition and postoperative quality of recovery after beach chair position shoulder surgery

We examined the influence of age in beach chair position shoulder surgery and postoperative quality of recovery by conducting a single-site, observational, cohort study comparing younger aged (18-40 years) versus older aged (at least 60 years) patients admitted for elective shoulder surgery in the beach chair position. Endpoints were dichotomous return of function to each patient's individual preoperative baseline as assessed using the postoperative quality of recovery scale; measuring cognition, nociception, physiological, emotional, functional activities and overall perspective. We recruited 112 (41 younger and 71 older aged) patients. There was no statistical difference in cognitive recovery at day three postoperatively (primary outcome): 26/32 younger patients (81%) versus 43/60 (72%) older patients, P=0.45. Rates of recovery were age-dependent on domain and time frame (secondary outcomes), with older patients recovering faster in the nociceptive domain (P=0.02), slower in the emotional domain (P=0.02) and not different in the physiological, functional activities and overall perspective domains (all P >0.35). In conclusion, we did not show any statistically significant difference in cognitive outcomes between younger and older patients using our perioperative anaesthesia and analgesia management protocol. Irrespective of age, 70% of patients recovered by three months in all domains.

Longitudinal Study of the Association between General Anesthesia and Increased Risk of Developing Dementia

The association between exposure to general anesthesia (GA) and the risk of dementia is still undetermined. To investigate a possible link to the development of dementia in older people who have undergone GA, we analyzed nationwide representative cohort sample data from the Korean National Health Insurance Service. The study cohort comprised patients over 55 years of age who had undergone GA between January 2003 and December 2004 and consisted of 3100 patients who had undergone GA and 12,400 comparison subjects who had not received anesthesia. After the nine-year follow-up period, we found the overall incidence of dementia was higher in the patients who had undergone GA than in the comparison group (10.5 vs. 8.8 per 1000 person-years), with the risk being greater for women (adjusted HR of 1.44; 95% CI, 1.19–1.75) and those with comorbidities (adjusted HR of 1.39; 95% CI, 1.18–1.64). Patients who underwent GA showed higher risks for Alzheimer’s disease and vascular dementia (adjusted HR of 1.52; 95% CI, 1.27–1.82 and 1.64; 95% CI, 1.15–2.33, respectively). This longitudinal study using a sample cohort based on a nationwide population sample demonstrated a significant positive association between GA and dementia, including Alzheimer’s disease and vascular dementia.

ACSL4 contributes to sevoflurane-induced ferroptotic neuronal death in SH-SY5Y cells via the 5' AMP-activated protein kinase/mammalian target of rapamycin pathway

Background

Acyl-CoA synthetase long chain family member 4 (ACSL4) has been reported to serve as a major player in the progress of ferroptosis in various diseases. Nevertheless, the functional role and mechanism of ACSL4 in sevoflurane (sev)-induced neuronal death has never been elucidated.

Methods

Cell viability was assessed using Cell Counting Kit-8 (CCK-8). Iron levels, reactive oxygen species (ROS) production, and malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), and glutathione (GSH) content were determined to assess ferroptosis level. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blot were undertaken for the measurement of gene expression.

Results

Sev hindered the viability of SH-SY5Y cells and suppression of ferroptosis by ferrostatin-1 (Fer-1) mitigated sev-induced inhibition of SH-SY5Y cell viability. Sev treatment increases the Fe²⁺ level and decreases the mRNA levels of SLC7A11 and GPX4 in SH-SY5Y cells. Sev increased the expression of ACSL4. Moreover, silencing of ACSL4 could abrogate sev-induced cell damage, as evidenced by increases in cell viability, GPX4 protein levels, and decreases in iron levels, ROS production, and MDA and 4-HNE content. Remarkably, sev hindered the activation of the 5' AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) signaling, which was diminished by knockdown of ACSL4. Moreover, inhibition of the AMPK/mTOR signaling by compound C could mitigate the protective effect of ACSL4 silencing against sev-induced ferroptotic cell death.

Conclusions

Downregulation of ACSL4 restrained sev-induced ferroptotic cell death via AMPK/mTOR signaling, providing the basis for an approach to alleviate sev-induced postoperative cognitive dysfunction (POCD).

Major surgery leads to a proinflammatory phenotype: Differential gene expression following a laparotomy

BACKGROUND

The trauma of surgery is a neglected area of research. Our aim was to examine the differential expression of genes of stress, metabolism and inflammation in the major organs of a rat following a laparotomy.

MATERIALS AND METHODS

Anaesthetised Sprague-Dawley rats were randomised into baseline, 6-hr and 3-day groups (n = 6 each), catheterised and laparotomy performed. Animals were sacrificed at each timepoint and tissues collected for gene and protein analysis. Blood stress hormones, cytokines, endothelial injury markers and coagulation were measured.

RESULTS

Stress hormone corticosterone significantly increased and was accompanied by significant increases in inflammatory cytokines, endothelial markers, increased neutrophils (6-hr), higher lactate (3-days), and coagulopathy. In brain, there were significant increases in M1 muscarinic (31-fold) and α-1A-adrenergic (39-fold) receptor expression. Cortical expression of metabolic genes increased ∼3-fold, and IL-1β by 6-fold at 3-days. Cardiac β-1-adrenergic receptor expression increased up to 8.4-fold, and M2 and M1 muscarinic receptors by 2 to 4-fold (6-hr). At 3-days, cardiac mitochondrial gene expression (Tfam, Mtco3) and inflammation (IL-1α, IL-4, IL-6, MIP-1α, MCP-1) were significantly elevated. Haemodynamics remained stable. In liver, there was a dramatic suppression of adrenergic and muscarinic receptor expression (up to 90%) and increased inflammation. Gut also underwent autonomic suppression with 140-fold increase in IL-1β expression (3-days).

CONCLUSIONS

A single laparotomy led to a surgical-induced proinflammatory phenotype involving neuroendocrine stress, cortical excitability, immune activation, metabolic changes and coagulopathy. The pervasive nature of systemic and tissue inflammation was noteworthy. There is an urgent need for new therapies to prevent hyper-inflammation and restore homeostasis following major surgery.

Enriched Environment Prevents Surgery-Induced Persistent Neural Inhibition and Cognitive Dysfunction

Perioperative neurocognitive disorders (PND) encompass short-term delirium and long-term cognitive dysfunction. Aging increases the susceptibility to PND, yet the neural mechanism is not known. In this study, we monitored the dynamic changes of neuronal activity in the prelimbic cortex before and after surgery. We found that anesthesia combined with surgery, but not anesthesia alone, induced a prolonged decrease in neuronal activity during the post-operation period in the aged mice, but not in the adult mice. The prolonged decrease in neuronal activity was accompanied by surgery-induced microglial activation and proinflammatory cytokines expression. Importantly, we found that the enriched environment (EE) completely prevented both the prolonged neural inhibition and neuroinflammation, and improved cognitive function in the aged mice. These results indicate that the prolonged neural inhibition correlated to PND and that EE before the surgery could effectively alleviate the surgery- induced cognitive dysfunction.

Preoperative Peripheral Nerve Blocks in Orthopaedic Trauma Surgery: A Guide to Diagnosis-Based Treatment

Perioperative pain management remains an important focus of both patient and provider attention in orthopaedic trauma surgery. There is a constant effort to improve pain management while decreasing opioid consumption, and peripheral nerve blocks are a safe and effective way to achieve these two goals. This is particularly relevant because more procedures are being done in outpatient surgery centers, and the need to safely provide analgesia without the systemic risk of opioid medications is paramount. The primary goal of this article was to describe the diagnosis-based approach for the utilization of preoperative peripheral nerve blocks in perioperative care for orthopaedic trauma surgery procedures based on the experience and current practice at our center.

Overexpression of miR-133b protects against isoflurane-induced learning and memory impairment

A number of microRNAs (miRs) have been identified as being involved in the regulation of anesthesia-induced cognitive impairment. The aim of the present study was to investigated the role and potential mechanism of miR-133b in isoflurane-induced learning and memory impairment. An animal model of isoflurane exposure was established using neonatal Sprague-Dawley rats. The rats were trained for Morris water maze (MWM) testing to assess their spatial learning and memory ability. Reverse transcription-quantitative polymerase chain reaction was used for the measurement of miR-133b expression in hippocampal tissues and primary hippocampal neuron cultures. Cell viability was assessed using a Cell Counting Kit-8 assay, and flow cytometric analysis was used to determine the rate of apoptosis. The MWM test results indicated that during the training period, the time required to locate the platform was significantly increased for rats exposed to isoflurane, and this increased time was reduced by the overexpression of miR-133b. The results of a probe trial indicated that isoflurane exposure increased escape latency and decreased the time spent in the platform area for isoflurane-treated rats; however, these effects were reversed by the injection of miR-133b agomir. The in vitro experiments demonstrated that the overexpression of miR-133b attenuated the reduction of neuronal cell viability induced by isoflurane, and inhibited the isoflurane-induced apoptosis of hippocampal neurons. In conclusion, the present study revealed that the overexpression of miR-133b attenuated isoflurane-induced learning and memory impairment in rats. Furthermore, miR-133b overexpression promoted the viability of hippocampal neurons and their resistance to apoptosis when exposed to isoflurane.

Postoperative cognitive dysfunction after endovascular treatments for unruptured intracranial aneurysms: A pilot study

OBJECTIVE

Post operative cognitive dysfunction (POCD) has been widely observed after major surgery, particularly in elderly patients with general anesthesia (GA). However, a specific unanswered question is whether different approaches to anesthetic managements are associated with different cognitive outcomes after endovascular treatments for unruptured intracranial aneurysms (UIAs). The purpose of this study is to assess the correlation of POCD with GA versus monitored anesthesia care (MAC).

METHODS

We performed a pragmatic, prospective study to assess the association between different anesthetic approaches and POCD. We compared the pre- and post-procedural Montreal Cognitive Assessment (MoCA) scores in patients with normal cognition who underwent treatments of UIAs with various endovascular methods, using either GA or MAC.

RESULTS

A total of 23 patients with UIAs were enrolled in the study. Seven (30.4%) and sixteen (69.6%) UIAs were treated without perioperative complications under GA or MAC, respectively. There was a significant decline in the post-procedural MoCA score under GA (mean difference  =  1.14; 95% confidence interval  =  [0.42-1.87], P < 0.01). By contrast, there was no significant difference of MoCA score between pre- and post-procedure under MAC (mean difference  =  0.19; 95% confidence interval  =  [-0.29-0.67], P  =  0.59).

CONCLUSIONS

Treating UIAs using MAC was associated with a decrease in POCD as compared to GA in patients undergoing endovascular treatments for UIAs with normal cognition. Larger randomized studies are needed to confirm these findings.

Comparing the effect of xenon and sevoflurane anesthesia on postoperative neural injury biomarkers: a randomized controlled trial

General anesthesia and surgery are associated with an increase in neural injury biomarkers. Elevations of these neural injury biomarkers in the perioperative period are associated with postoperative delirium. Xenon has been shown to be protective against a range of neurological insults in animal models. It remains to be seen if xenon anesthesia is neuroprotective in the perioperative setting in humans. Twenty-four participants scheduled for lithotripsy were randomized to receive either xenon or sevoflurane general anesthesia. There was no statistically significant difference in the concentrations of postoperative neural injury biomarkers between the xenon and sevoflurane group. Following the procedure there was a significant increase in the concentration from baseline of all three biomarkers at 1 hour post-induction with a return to baseline at 5 hours. General anesthesia for lithotripsy was associated with a significant increase at 1 hour post-induction in the neural injury biomarkers total tau, neurofilament light and tau phosphorylated at threonine 181, a marker of tau phosphorylation. The protocol was approved by the St. Vincent’s Hospital Melbourne Ethics Committee (approval No. HREC/18/SVHM/221) on July 20, 2018 and was registered with the Australia New Zealand Clinical Trials Registry (registration No. ACTRN12618000916246) on May 31, 2018.

Preventing Delirium and Promoting Long-Term Brain Health: A Clinical Trial Design for the Perioperative Cognitive Enhancement (PROTECT) Trial

BACKGROUND

Perioperative neurocognitive disorders (PND), including postoperative delirium (POD), are common in older adults and, for many, precipitate functional decline and/or dementia.

OBJECTIVE

In this protocol, we describe a novel multidisciplinary, multicomponent perioperative intervention that seeks to prevent or reduce POD and associated cognitive decline.

METHODS

We will conduct a prospective, single-blind, pragmatic, randomized-controlled trial to compare our tailored multi-disciplinary perioperative pathway against current standard of care practices. We will recruit a total of 692 elective surgical patients aged 65 years or more and randomize them in a 1:1 design. Our perioperative intervention targets delirium risk reduction strategies by emphasizing the importance of early mobilization, nutrition, hydration, cognitive orientation, sensory aids, and avoiding polypharmacy. To promote healthy behavior change, we will provide a tailored psychoeducation program both pre- and postoperatively, focusing on cardiovascular and psychosocial risks for cognitive and functional decline.

RESULTS

Our primary outcome is the incidence of any PND (encapsulating POD and mild or major postoperative neurocognitive disorder) at three months postoperative. Secondary outcomes include any incidence of POD or neurocognitive disorder at 12 months. A specialized delirium screening instrument, the Confusion Assessment Method (3D-CAM), and a neuropsychological test battery, will inform our primary and secondary outcomes.

CONCLUSION

Delirium is a common and debilitating postoperative complication that contributes to the cognitive and functional decline of older adults. By adopting a multicomponent, multidisciplinary approach to perioperative delirium prevention, we seek to reduce the burden of delirium and subsequent dementia in older adults.

Tricaine Methanesulfonate (MS222) Has Short-Term Effects on Young Adult Zebrafish (Danio rerio) Working Memory and Cognitive Flexibility, but Not on Aging Fish

Exposure to anesthetic drugs is common in biomedical sciences being part of routine procedures in different translational species, however its impacts on memory and cognition are still debated, having different impacts depending on drug and age. The zebrafish (Danio rerio) is a translational species widely used in behavioral neuroscience, where tricaine methanesulfonate (MS222) is the most acceptable and used drug when conducting routine procedures. Based on this, we investigated the effects of MS222 (100 mg/l) in young adults and aging zebrafish 1, 2, 3, and 7 days after exposure. Animals' were submitted to the anesthetic procedure until loss of body posture, slowing of opercular movements and lack of response to tail touch with a plastic pipette were achieved, then further left in the drug for 3 min. After that, animals (6 mpf vs. 24 mpf) were transferred to a recovery tank until fully recovered and transferred back to their housing system until further testing in the free movement pattern (FMP) Y-maze, which assesses zebrafish working memory and cognitive lexibility. Young animals had significant impairment in their working memory and cognitive flexibility 1 and 2 days after the exposure to MS222, being fully recovered by day 3 and with no effects 7 days post drug exposure. Increased repetitions were also observed for animals exposed to MS222 which could indicate increased stress-related response in animals up to 2 days after drug exposure. No drug effect was observed in aging animals besides their natural decreased alternations and working memory. Overall, behavioral experiments after routine procedures using MS222 should be performed with caution and need to be delayed, at least 3 days after exposure where working memory, cognitive flexibility, and repetitive behavior are back to normal.

The effects of anaesthetics and sedatives on brain inflammation

Microglia are involved in many dynamic processes in the central nervous system (CNS) including the development of inflammatory processes and neuromodulation. Several sedative, analgesic or anaesthetic drugs, such as opioids, ∝2-adrenergic agonists, ketamine, benzodiazepines and propofol can cause both neuroprotective and harmful effects on the brain. The purpose of this review is to present the main findings on the use of these drugs and the mechanisms involved in microglial activation. Alpha 2-adrenergic agonists, propofol and benzodiazepines have several pro- or anti-inflammatory effects on microglia. Long-term use of benzodiazepines and propofol causes neuroapoptotic effects and α2-adrenergic agonists may attenuate these effects. Conversely, morphine and fentanyl may have proinflammatory effects, causing behavioural changes in patients and changes in cell viability in vitro. Conversely, chronic administration of morphine induces CCL5 chemokine expression in microglial cells that promotes their survival.

Anesthesiology: Resetting Our Sights on Long-term Outcomes: The 2020 John W. Severinghaus Lecture on Translational Science

Anesthesiologists have worked relentlessly to improve intraoperative anesthesia care. They are now well positioned to expand their horizons and address many of the longer-term adverse consequences of anesthesia and surgery. Perioperative neurocognitive disorders, chronic postoperative pain, and opioid misuse are not inevitable adverse outcomes; rather, they are preventable and treatable conditions that deserve attention. The author's research team has investigated why patients experience new cognitive deficits after anesthesia and surgery. Their animal studies have shown that anesthetic drugs trigger overactivity of "memory-blocking receptors" that persists after the drugs are eliminated, and they have discovered new strategies to preserve brain function by repurposing available drugs and developing novel therapeutics that inhibit these receptors. Clinical trials are in progress to examine the cognitive outcomes of such strategies. This work is just one example of how anesthesiologists are advancing science with the goal of improving the lives of patients.

Update on the Mechanism and Treatment of Sevoflurane-Induced Postoperative Cognitive Dysfunction

Sevoflurane is one of the most widely used anesthetics for the induction and maintenance of general anesthesia in surgical patients. Sevoflurane treatment may increase the incidence of postoperative cognitive dysfunction (POCD), and patients with POCD exhibit lower cognitive abilities than before the operation. POCD affects the lives of patients and places an additional burden on patients and their families. Understanding the mechanism of sevoflurane-induced POCD may improve prevention and treatment of POCD. In this paper, we review the diagnosis of POCD, introduce animal models of POCD in clinical research, analyze the possible mechanisms of sevoflurane-induced POCD, and summarize advances in treatment for this condition.

Effect of general anesthesia combined with epidural anesthesia on circulation and stress response of patients undergoing hysterectomy

OBJECTIVE

To investigate the effect of general anesthesia combined with epidural anesthesia on circulation and stress response of patients undergoing hysterectomy.

METHODS

A total of 97 patients undergoing hysterectomy in our hospital from December 2017 to December 2019 were recruited as the research participants, of whom 44 patients (general anesthesia group) received general anesthesia and 53 patients (joint group) received general anesthesia combined with epidural anesthesia during operation. The hemodynamic indexes, anesthetic effect, anesthetic recovery effect, cognitive function, and stress substance levels of the two groups were compared.

RESULTS

Compared with the general anesthesia group, the SBP and HR of the patients in the joint group were more stable, and the anesthesia effect and recovery effect in the joint group were better. The MMSE score of the joint group at 6 h and 12 h after anesthesia was significantly higher than that of the general anesthesia group (P < 0.001). There was no significant difference in the levels of adrenaline and norepinephrine between the two groups before operation (P > 0.05). The levels of stress substances in the two groups increased at 30 min after operation (P < 0.001), and those in the joint group were significantly lower than those in the control group (P < 0.001).

CONCLUSION

Compared with general anesthesia, general anesthesia combined with epidural anesthesia produces better anesthetic effect in hysterectomy, has less influence on patients' circulatory response and can reduce stress response.

Surgery Performed Under Propofol Anesthesia Induces Cognitive Impairment and Amyloid Pathology in ApoE4 Knock-In Mouse Model

Background: Postoperative cognitive dysfunction (POCD) following anesthesia and surgery is a common and severe complication, especially in elderly patients. A pre-existing cognitive impairment may impart susceptibility to further cognitive dysfunction; the mechanism remains unclear. We hypothesized that the specific impacts of anesthesia and surgery on individuals with preclinical Alzheimer’s disease (AD) may render them more susceptible to an increase in the risk of cognitive impairment. The aim of this study was to compare the cognitive impairment between normal adult mice and those with preclinical AD after propofol anesthesia and surgery.

Methods: We performed abdominal surgery in cognitively pre-symptomatic, 5-month-old male mice with sporadic AD (apolipoprotein E4 allele, ApoE4-KI) and age-matched (C57BL/6J) controls. Propofol anesthesia (170 mg/kg) was induced via retro-orbital injection over 2 h. Morris water maze (MWM) and Y-maze tests were conducted 2 days before and 2, 4, and 7 days after surgery. The mean escape latencies and spontaneous alternation percentages were the major outcomes. Neuronal apoptosis in hippocampal sections was evaluated using the terminal dUTP nick-end labeling (TUNEL) assay. Hippocampal amyloid beta (Aβ) levels were assessed via quantitative immunohistochemistry (IHC).

Results: The control mice exhibited increased mean escape latencies of MWM at postoperative 2 and 4, but not at day 7; ApoE4-KI mice exhibited such increases at postoperative days 2, 4 and 7. Significant differences between ApoE4-KI and control mice in terms of the mean escape latencies were evident at days 2 and 7 (both P < 0.05). However, performance on a non-hippocampal memory tasks (Y-maze test) did not differ. More TUNEL-positive neurons were evident in the hippocampal CA3 region of ApoE4-KI mice at postoperative days 2 and 4, but not at day 7 compared to the control group (both P < 0.05). IHC revealed significantly elevated Aβ deposition in the hippocampal CA3 region of ApoE4-KI mice at postoperative days 4 and 7 compared to control mice (both P < 0.05).

Conclusions: Propofol anesthesia followed by surgery induced persistent changes in cognition, and pathological hippocampal changes in pre-symptomatic, but vulnerable AD mice. It would be appropriate to explore whether preclinical AD patients are more vulnerable to POCD development.

Longitudinal assessment of preoperative dexamethasone administration on cognitive function after cardiac surgery: a 4-year follow-up of a randomized controlled trial

Background

The pathogenesis of postoperative cognitive decline (POCD) is still poorly understood; however, the inflammatory response to surgical procedures seems likely to be involved. In addition, our recent randomized controlled trial showed that perioperative corticosteroid treatment may ameliorate early POCD after cardiac surgery. To assess the long-term effect of dexamethasone administration on cognitive function, we conducted a 4-year follow-up.

Methods

The patients were randomized to receive a single intravenous bolus of 0.1 mg kg^− 1 dexamethasone or placebo 10 h before elective cardiac surgery. The endpoint in both groups was POCD incidence on the 6th day and four years postoperatively.

Results

Of the 161 patients analyzed previously, the current follow-up included 116 patients. Compared to the 62 patients in the placebo group, the 54 patients in the dexamethasone group showed a lower incidence of POCD on the 6th day (relative risk (RR), 0.510; 95 % confidence interval (CI), 0.241 to 1.079; p = 0.067, time interval also analyzed previously) and four years (RR, 0.459; 95 % CI, 0.192 to 1.100; p = 0.068) after cardiac surgery. The change in cognitive status between the two postoperative measurements was not significant (p = 0.010) among the patients in the dexamethasone group, in contrast to patients in the placebo group (p = 0.673).

Conclusions

Although statistical significance was not reached in the current study, the prophylactic administration of dexamethasone seems to be useful to prevent POCD development following cardiac surgery. However, further large multicenter research is needed to confirm these directions.

Trial registration

ClinicalTrials.gov identifier: NCT02767713 (10/05/2016).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01348-z.

[Effects of dexmedetomidine doses on postoperative cognitive dysfunction and serum β- amyloid and cytokine levels in elderly patients after spine surgery: a randomized controlled trial]

OBJECTIVE

To explore the immunomodulatory mechanism and optimal dose of dexmedetomidine (DEX) for preventing postoperative cognitive dysfunction (POCD) in elderly patients undergoing spinal surgery.

OBJECTIVE

A total of 120 elderly patients undergoing elective spinal surgery with general anesthesia were randomized into 4 groups to receive a loading dose of 0.3 μg/kg DEX for 10 min before anesthesia induction followed by maintenance doses of 0.2, 0.5, and 0.8 μg · kg^-1·h^-1 (low-, medium-, and high-dose DEX groups, respectively) or an equal volume of normal saline (control group). DEX and saline was discontinued 40 min before the end of the surgery. Before induction (D₀) and on day 1 (D₁), day 3 (D₂) and day 7 (D₃) after the operation, the cognitive function of the patients was assessed using the MMSE scale and their serum levels of β-amyloid (Aβ), TNF-α, IL-1β and IL-6 were measured. The occurrence of adverse effects including bradycardia and hypotension and the recovery time of the patients were recorded.

OBJECTIVE

Compared with those on D₀, serum levels of Aβ, IL-1β, IL-6, and TNF-α on D₁ were markedly increased in all the groups (P < 0.05); the levels of Aβ decreased to the baseline level on D₃ in medium- and high-dose DEX groups (P > 0.05) but remained high in the other two groups. On D₂, TNF-α, L-1β and IL-6 recovered their baseline levels in medium- and high-dose DEX groups (P > 0.05) but remained elevated in the other two groups. The incidences of POCD in medium- and high-dose DEX groups were comparable but significantly lower than that in the control group (P < 0.05). The incidences of hypotension and bradycardia were the highest in high-dose DEX group (P < 0.01), which also had longer recovery time than the other 3 groups (P < 0.05).

OBJECTIVE

With a loading dose of 0.3 μg/kg followed by a maintenance doses of 0.5 μg · kg^-1·h^-1, DEX can effectively reduce the incidence of POCD in elderly patients undergoing spinal surgery by inhibiting the production of Aβ and pro-inflammatory cytokines.

Analysis of Brain Functions in Men with Prostate Cancer under Androgen Deprivation Therapy: A One-Year Longitudinal Study

The relationship between cognitive decline and androgen deprivation therapy (ADT) under luteinizing hormone-releasing hormone (LHRH) analogues is unclear, and there is a scarcity of longitudinal studies considering the interaction between cognition, depressive symptoms and sleep quality in men with prostate cancer (PCa) treated with ADT. This study aimed to determine if there were differences in the scores obtained in cognitive assessment, depressive symptoms, and sleep quality after one year of ADT and determine the interrelations between sleep, mood, and cognitive status. A prospective longitudinal observational study was designed, in which a cohort of men (mean age was 70.8 years) newly treated with androgen-deprivation therapy was assessed in the first six months of treatment and 12 months later. Analysis of cognitive function by the Mini-Mental State Examination (MMSE) scores indicated a significant (p < 0.05) increase after one year of treatment and by the Brief Scale for Cognitive Evaluation (BCog) scores indicated no changes in the scores before and after one year of treatment. Analysis of depressive symptoms with the Geriatric Depression Scale and sleep quality with the Athens Insomnia Scale (AIS) scores showed significant (p < 0.05) changes after one year of treatment with ADT, with men describing more depressive symptoms and more sleep disturbances. No statistically significant differences were found in the cognitive performance between men with impaired sleep or depression results and those without them. Our study showed no clinical evidence of the relationship between ADT under luteinizing hormone-releasing hormone (LHRH) analogues and cognitive deterioration in 1-year follow-up, but there are impairments in the sleep quality in men with PCa undergoing ADT and an increase in depressive symptoms which has important implications for clinicians as they would impair quality of life and adherence to treatment.

Gut microbiota: a new player in the pathogenesis of perioperative neurocognitive disorder?

Perioperative neurocognitive disorder (PND), including postoperative delirium and postoperative cognitive dysfunction (POCD), is a common postoperative complication in elderly patients, who represent an expanding segment of our population. PND is a multifactorial disease resulting in higher morbidity and mortality. The precise mechanism of PND is yet to be fully delineated. Identifying the modifiable risk factors and mechanisms for PND would be an important step forward in preventing such adverse events and thus improving patients' outcomes. It is increasingly recognized that gut microbiota also manifest effects in the central nervous system via the microbiota-gut-brain axis, which has emerged as an important player in shaping aspects of behavior and cognitive function. Recent studies have found that patients with cognitive dysfunction after surgery and anesthesia have obvious gut microbiome disorders. These findings are paralleled by a growing body of preclinical investigations aimed at better understanding how surgery and anesthesia affect the central nervous system and possibly contribute to cognitive decline. Here, we present a broad topical review of the literature supporting the role of gut microbiota in PND. We provide an overview of the mechanisms underlying the pathogenesis of PND from pre-clinical and human studies. Therefore, gut microbiota could be a putative therapeutic target for PND in the future.

Inhibition of cAMP-phosphodiesterase 4 (PDE4) potentiates the anesthetic effects of Isoflurane in mice

Despite major advances, there remains a need for novel anesthetic drugs or drug combinations with improved efficacy and safety profiles. Here, we show that inhibition of cAMP-phosphodiesterase 4 (PDE4), while not inducing anesthesia by itself, potently enhances the anesthetic effects of Isoflurane in mice. Treatment with several distinct PAN-PDE4 inhibitors, including Rolipram, Piclamilast, Roflumilast, and RS25344, significantly delayed the time-to-righting after Isoflurane anesthesia. Conversely, treatment with a PDE3 inhibitor, Cilostamide, or treatment with the potent, but non-brain-penetrant PDE4 inhibitor YM976, had no effect. These findings suggest that potentiation of Isoflurane hypnosis is a class effect of brain-penetrant PDE4 inhibitors, and that they act by synergizing with Isoflurane in inhibiting neuronal activity. The PDE4 family comprises four PDE4 subtypes, PDE4A to PDE4D. Genetic deletion of any of the four PDE4 subtypes in mice did not affect Isoflurane anesthesia per se. However, PDE4D knockout mice are largely protected from the effect of pharmacologic PDE4 inhibition, suggesting that PDE4D is the predominant, but not the sole PDE4 subtype involved in potentiating Isoflurane anesthesia. Pretreatment with Naloxone or Propranolol alleviated the potentiating effect of PDE4 inhibition, implicating opioid- and β-adrenoceptor signaling in mediating PDE4 inhibitor-induced augmentation of Isoflurane anesthesia. Conversely, stimulation or blockade of α₁-adrenergic, α₂-adrenergic or serotonergic signaling did not affect the potentiation of Isoflurane hypnosis by PDE4 inhibition. We further show that pretreatment with a PDE4 inhibitor boosts the delivery of bacteria into the lungs of mice after intranasal infection under Isoflurane, thus providing a first example that PDE4 inhibitor-induced potentiation of Isoflurane anesthesia can critically impact animal models and must be considered as a factor in experimental design. Our findings suggest that PDE4/PDE4D inhibition may serve as a tool to delineate the exact molecular mechanisms of Isoflurane anesthesia, which remain poorly understood, and may potentially be exploited to reduce the clinical doses of Isoflurane required to maintain hypnosis.

Understanding the Effects of Anesthesia on Cortical Electrophysiological Recordings: A Scoping Review

General anesthesia in animal experiments is an ethical must and is required for all the procedures that are likely to cause more than slight or momentary pain. As anesthetics are known to deeply affect experimental findings, including electrophysiological recordings of brain activity, understanding their mechanism of action is of paramount importance. It is widely recognized that the depth and type of anesthesia introduce significant bias in electrophysiological measurements by affecting the shape of both spontaneous and evoked signals, e.g., modifying their latency and relative amplitude. Therefore, for a given experimental protocol, it is relevant to identify the appropriate anesthetic, to minimize the impact on neuronal circuits and related signals under investigation. This review focuses on the effect of different anesthetics on cortical electrical recordings, examining their molecular mechanisms of action, their influence on neuronal microcircuits and, consequently, their impact on cortical measurements.

The risk factors for cognitive dysfunction in elderly patients after laparoscopic surgery: A retrospective analysis

Postoperative cognitive dysfunction (POCD) is very common in clinical settings, it is necessary to analyze the risk factors for POCD in elderly patients after laparoscopic surgery to provide insights into clinical surgery management.Elderly patients undergone laparoscopy between September 1, 2018 and March 31, 2020 were included. The mini-mental state examination (MMSE) scale was used to evaluate the POCD, and the characteristics and clinical data of patients with and without POCD were collected and compared. Logistic regression was used to analyze the potential influencing factors.A total of 572 patients with laparoscopic surgery were included. The incidence of POCD was 11.89%. There were significant differences in the history of cerebral infarction, preemptive analgesia, preoperative use of dexmedetomidine, general anesthesia combined with continuous epidural block, duration of surgery, low SpO2 during anesthesia induction, PaCO2 after pneumoperitoneum, postoperative PCEA and VAS score at the third day after operation (all P < .05). Logistic regression analysis revealed that history of cerebral infarction (OR3.12, 1.02∼5.13), low SpO2 during anesthesia induction (OR2.03, 1.19∼4.47), Longer duration of surgery (OR1.82, 1.01∼3.16) were risk factors for POCD in elderly patients with laparoscopic surgery, while postoperative PCEA (OR0.43, 0.01∼0.91), General anesthesia combined with continuous epidural block (OR0.59, 0.04∼0.87), preoperative use of dexmedetomidine (OR0.70, 0.08∼0.94) and preemptive analgesia (OR0.75, 0.13-0.90) were the protective factors for POCD in elderly patients with laparoscopic surgery.For the elderly patients undergoing laparoscopic surgery, the health care providers should be fully alert to the POCD based on those relevant factors.

Gene-Specific DNA Methylation Linked to Postoperative Cognitive Dysfunction in Apolipoprotein E3 and E4 Mice

BACKGROUND

Geriatric surgical patients are at higher risk of developing postoperative neurocognitive disorders (NCD) than younger patients. The specific mechanisms underlying postoperative NCD remain unknown, but they have been linked to genetic risk factors, such as the presence of APOE4, compared to APOE3, and epigenetic modifications caused by exposure to anesthesia and surgery.

OBJECTIVE

To test the hypothesis that compared to E3 mice, E4 mice exhibit a more pronounced postoperative cognitive impairment associated with differential DNA methylation in brain regions linked to learning and memory.

METHODS

16-month-old humanized apolipoprotein-E targeted replacement mice bearing E3 or E4 were subjected to surgery (laparotomy) under general isoflurane anesthesia or sham. Postoperative behavioral testing and genome-wide DNA methylation were performed.

RESULTS

Exposure to surgery and anesthesia impaired cognition in aged E3, but not E4 mice, likely due to the already lower cognitive performance of E4 prior to surgery. Cognitive impairment in E3 mice was associated with hypermethylation of specific genes, including genes in the Ephrin pathway implicated in synaptic plasticity and learning in adults and has been linked to Alzheimer's disease. Other genes, such as the Scratch Family Transcriptional Repressor 2, were altered after surgery and anesthesia in both the E3 and E4 mice.

CONCLUSION

Our findings suggest that the neurocognitive and behavioral effects of surgery and anesthesia depend on baseline neurocognitive status and are associated with APOE isoform-dependent epigenetic modifications of specific genes and pathways involved in memory and learning.