Effect of inhalational anaesthetic on postoperative cognitive dysfunction following radical rectal resection in elderly patients with mild cognitive impairment

Postoperative neurocognitive disorders in ambulatory surgery: a narrative review

Postoperative neurocognitive disorders (PoNCDs), such as postoperative delirium and cognitive dysfunction or decline can occur after surgery, especially in older patients. This significantly affects patient morbidity and surgical outcomes. Among various risk factors, recent studies have shown that preoperative frailty is associated with developing these conditions. Although the mechanisms underlying PoNCDs remain unclear, neuroinflammation appears to play an important role in their development. For the prevention and treatment of PoNCDs, medication modification, a balanced diet, and prehabilitation and rehabilitation programs have been suggested. The risk of developing PoNCDs is thought to be lower in ambulatory patients. However, owing to technological advancements, an increasing number of older and sicker patients are undergoing more complex surgeries and are often not closely monitored after discharge. Therefore, equal attention should be paid to all patient populations. This article presents an overview of PoNCDs and highlights issues of particular interest for ambulatory surgery.

Current perspectives on postoperative cognitive dysfunction in geriatric patients: insights from clinical practice

Postoperative cognitive dysfunction (POCD) is a common and serious postoperative complication in elderly patients, affecting cognitive function and quality of life. Its pathophysiology is complex, involving age-related cognitive decline, surgical and anesthetic factors, systemic and neuroinflammation, as well as genetic and environmental contributors. Comprehensive preoperative assessment and optimization, the selection of appropriate anesthetic agents, minimally invasive surgical techniques, and early postoperative rehabilitation and cognitive training are effective strategies to reduce the incidence of POCD. Recent research suggests that anti-inflammatory drugs and neuroprotective agents may be promising in preventing POCD. Additionally, non-pharmacological interventions, including cognitive and physical training, have shown positive effects. Future research directions should include large-scale clinical trials and mechanistic studies to further understand and manage POCD, along with integrating new findings into clinical practice. Continuous education and training for healthcare professionals are essential to ensure the effective application of the latest research findings in patient care. Through multidisciplinary collaboration and ongoing improvements, these efforts can significantly enhance the cognitive function and quality of life of elderly surgical patients.

Peripheral inflammation as a potential mechanism and preventive strategy for perioperative neurocognitive disorder under general anesthesia and surgery

General anesthesia, as a commonly used medical intervention, has been widely applied during surgical procedures to ensure rapid loss of consciousness and pain relief for patients. However, recent research suggests that general anesthesia may be associated with the occurrence of perioperative neurocognitive disorder (PND). PND is characterized by a decline in cognitive function after surgery, including impairments in attention, memory, learning, and executive functions. With the increasing trend of population aging, the burden of PND on patients and society's health and economy is becoming more evident. Currently, the clinical consensus tends to believe that peripheral inflammation is involved in the pathogenesis of PND, providing strong support for further investigating the mechanisms and prevention of PND.

Effects of different anesthetic regimens on postoperative cognitive function of elderly patients undergoing thoracic surgery: a double-blinded randomized controlled trial

OBJECTIVE

Postoperative cognitive dysfunction (POCD) is a serious surgical complication. We assessed the different POCD incidences between anesthesia using sevoflurane and sevoflurane combined with dexmedetomidine, with propofol-based sedation in elderly patients who underwent a thoracic surgical procedure.

METHODS

A total of 90 patients aged 65 to 80 years old who underwent a thoracic surgical procedure at our hospital and 15 nonsurgical participants as controls, were enrolled in this study. Patients were divided in a randomized 1:1:1 ratio into 3 groups. All participants were randomized into a trial with three anesthesia groups (P, PS, PSD) or a control group (C) of healthy matches. All trial groups received distinct anesthetic combinations during surgery, while controls mirrored patient criteria.Group P (propofol and remifentanil were maintained during the surgery), Group PS (propofol, remifentanil, and sevoflurane were maintained during the surgery), and Group PSD (propofol, remifentanil, sevoflurane, and dexmedetomidine were maintained during the surgery).All participants were rated using a series of cognitive assessment scales before and three days after surgery. All participants were interviewed over the telephone, 7 days, 30 days, and 90 days postoperatively.

RESULTS

POCD incidences in the PSD (combined anesthetization with propofol, sevoflurane, and dexmedetomidine) group was significantly lower than that in the PS (combined anesthetization with propofol and sevoflurane) group, 1 day post-surgery (10.0% vs. 40.0%, P = 0.008), and the results were consistent at 3 days post-surgery. When the patients were assessed 7 days, 30 days, and 90 days postoperatively, there was no significant difference in POCD incidence among the three groups. Multivariate logistic regression analysis of POCD one day after surgery showed that education level was negatively correlated with incidence of POCD (P = 0.018) and single lung ventilation time was positively correlated with incidence of POCD (P = 0.001).

CONCLUSION

For elderly patients who underwent a thoracic surgical procedure, dexmedetomidine sedation shows an obvious advantage on improving short-term POCD incidence, which is caused by sevoflurane.

Melatonin Ameliorates Sevoflurane Anesthesia-Induced Deficits in Learning and Memory of Aged Mice Through Nrf2 Signaling Related Ferroptosis

Our research aimed at investigating the protective effects in aged mice exposed to sevoflurane anesthesia. To assess learning and memory abilities and exploratory behavior, the novel object recognition (NOR) test, Morris water maze (MWM) test, and open field test were employed. Commercial kits were used to measure levels of malondialdehyde, nicotinamide adenine dinucleotide phosphate oxidase activity, superoxide dismutase activity, catalase activity, and iron. The messenger RNA and protein levels of ferritin heavy chain 1, nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1, and glutathione peroxidase 4 in the hippocampus were detected. Treatment with melatonin significantly ameliorated the decrease in exploration time of novel objects and the discrimination index induced by sevoflurane anesthesia. Melatonin also reduced escape latencies and increased the time spent in the target quadrant in the MWM test. In the open field test, melatonin-treated mice exhibited greater exploratory activity, including longer distances traveled and a higher number of rearing events. Further, melatonin treatment markedly decreased the levels of oxidative stress markers and iron in the hippocampus of aged mice exposed to sevoflurane anesthesia. However, the beneficial effects of melatonin were significantly attenuated following treatment with the Nrf2 inhibitor ML385. Our results suggest that melatonin could alleviate learning and memory impairment induced by sevoflurane anesthesia in aged mice through its antioxidant properties, partially through the Nrf2 pathway.

The effect of intravenous and inhalation anesthesia in general on the cognition of elderly patients undergoing non-cardiac surgery: a systematic review and meta-analysis

Background

Postoperative cognitive dysfunction (POCD) is a postoperative complication that often occurs in the elderly. This systematic review and meta-analysis aimed to compare intravenous anesthetics (propofol) with inhalation anesthetics (sevoflurane) regarding the occurrence of POCD in the elderly who underwent non-cardiac surgery.

Methods

The investigators searched for published articles from the PubMed, Embase, Web of Science, Scopus, Cochrane, and Clinicalkey databases. Clinical studies comparing the incidence of POCD in elderly patients undergoing intravenous or inhalation anesthesia in general were selected. Primary outcomes included the occurrence of POCD at 1, 3, and 7 days. The secondary outcomes were the patient's plasma S-100β protein levels (pg*mL-1) and delayed neurocognitive recovery incidence 5-7 days after surgery.

Results

Fifteen studies including 3,817 patients were enrolled in the systematic review. Ten studies involving 1,829 patients were enrolled in the meta-analysis. The results demonstrate that there was no difference between the intravenous and inhalation groups in the incidence of POCD within 1-7 days (95% CI 0.73-1.26, p = 0.77) and the occurrence of delayed neurocognitive recovery 5-7 days after surgery (95% CI -353.15 to -295.44, p = 0.28). Plasma S-100β protein levels in the intravenous anesthesia group were lower than those in the inhalation group (95% CI 0.48-1.24, p < 0.001).

Conclusion

For elderly patients undergoing non-cardiac surgery, inhalation anesthesia was comparable to intravenous anesthesia in terms of the occurrence of short-term POCD. Inhalation anesthesia may cause greater damage to the nervous system, with delayed recovery of cognitive function after 5-7 days showing no difference.

Systematic review

identifier (CRD42021251317).

Incidence and Factors Related to Prolonged Postoperative Cognitive Decline (POCD) in Elderly Patients Following Surgery and Anaesthesia: A Systematic Review

Aim

The aim of this systematic review is to explore the current literature to provide evidence regarding the incidence and risk factors of prolonged POCD in elderly patients following cardiac and non-cardiac surgical interventions.

Methods

The PubMed and Google Scholar databases were searched using appropriate keywords and search engines for adequate evidence from studies meeting the inclusion criteria so as to reveal the end-point, which was the presence of prolonged POCD in elderly patients following surgery and anaesthesia. The incidence of POCD at different time intervals and the variables predicting the occurrence of POCD were analysed.

Results

The results of 23 articles covering 5077 patients (3694 non cardiac and 1383 cardiac surgeries) were carefully analysed. POCD occurs from the first postoperative day and lasts for potentially long periods. The incidence of POCD in this review ranged from 2.2% to 35.7%. More specifically, it ranged from 2.2% to 31.5% in non-cardiac surgeries and 11.8% to 35.7% in patients who had undergone cardiac surgeries. Some of the independent risk factors (predictors) for the development of POCD were advanced age, high concentration of neuroinflammatory mediators detectable in plasma, low SpO2, longer anaesthetic and surgical duration, and depth of anaesthesia.

Conclusion

This review can only provide limited evidence of prolonged POCD (more than a year) and further research that involves better study designs, larger samples, involving longer follow-up, and at different sites (multicentre) is highly advised. This in turn may help researchers and clinicians to discover the actual causes and risk factors and develop appropriate preventive and treatment protocols to tackle POCD in the ageing surgical population.

Risk factors for postoperative cognitive dysfunction in elderly patients undergoing surgery for oral malignancies

We aimed to analyse postoperative cognitive dysfunction (POCD) incidence and risk factors in elderly adults who underwent surgery for oral malignancies. A total of 112 elderly patients (aged ≥ 55 years) were selected for expanded resection of oral malignancy and cervical lymphatic dissection at our institution from December 2020 to December 2021. Participants were cognitively evaluated using the neuropsychological test scale 1 day before and 7 days after surgery to determine whether they had developed POCD. Based on whether POCD occurred 7 days after surgery, patients were classified into the POCD and non-POCD groups. Logistic regression was applied to perioperative factors to analyse the risk factors for POCD onset. Seven days after surgery for oral malignancy, there were 37 (33.1%) POCD morbidities. Multiple factor logistic regression analysis revealed that venerable age (odds ratio [OR] = 1.269, 95% confidence interval [CI] 1.056-1.525, P < 0.05), low education levels (OR = 0.792, 95% CI 0.644-0.974, P < 0.05), hypertension (OR = 4.153, 95% CI 1.335-12.732, P < 0.05), dyssomnia (OR = 1.272, 95% CI 1.001-1.617, P < 0.05), prolonged anaesthesia (OR = 1.009, 95% CI 1.001-1.018, P < 0.05), and intraoperative hypotension (OR = 5.512, 95% CI 1.240-24.506, P < 0.05) increased the POCD risk in elderly patients who underwent surgery for oral malignancies. Venerable age, low knowledge reserve, hypertension, dyssomnia, prolonged anaesthesia, and intraoperative hypotension are independent risk factors for POCD in elderly patients with oral malignancies.

Cognitive function and delirium following sevoflurane or propofol anesthesia for valve replacement surgery: A multicenter randomized controlled trial

Cognitive dysfunction is a common postoperative neurological complication in patients undergoing valve replacement surgery. This study aimed to compare the effects of sevoflurane versus propofol-based total intravenous anesthesia on the incidence of cognitive dysfunction following valve replacement surgery. This multicenter, randomized, controlled double-blinded study was conducted in three teaching hospitals in China. Patients receiving on-pump valve replacement surgery were enrolled. Stratified block randomization was used to randomly assign patients 1:1 to receive sevoflurane (1.0-1.5 MAC) or propofol (2.0-3.0 mg/kg/h) for anesthesia maintenance. The primary outcome was the incidence of cognitive dysfunction assessed by four cognitive tests before, as well as 7-14 days after surgery. Patients were randomly assigned to receive sevoflurane anesthesia (n = 144) or propofol-based total intravenous anesthesia (n = 145). The incidence of postoperative cognitive dysfunction in the sevoflurane anesthesia group (31.9%) was significantly lower than that in the total intravenous anesthesia group (43.4%; relative risk 0.61, 95% confidence interval [CI]: 0.38-0.97, p = 0.044). There was no difference in the incidence of delirium between patients receiving sevoflurane and total intravenous anesthesia (27.8% [35/144] vs. 25.9% [35/145], 1.10, 95% CI: 0.64 to 1.90, p = 0.736). There was a significant difference in the Katz Index on day 3 after surgery (3 [0.9) vs. 3 (1.0], 0.095, 95% CI: 0.05 to 0.43, p = 0.012). No difference was observed in other outcomes between the two groups. For patients undergoing on-pump valve replacement surgery, sevoflurane anesthesia had a smaller effect on cognitive function and independence in daily life activities compared with propofol anesthesia.

Preventing postoperative cognitive dysfunction using anesthetic drugs in elderly patients undergoing noncardiac surgery: a systematic review and meta-analysis

Postoperative cognitive dysfunction (POCD) is a common neurological system disorder in surgical patients. The choice of anesthetic can potentially reduce POCD. The authors performed this network meta-analysis to compare different anesthetic drugs in reducing the incidence of POCD for elderly people undergoing noncardiac surgery. We searched MEDLINE, EMBASE, the Cochrane Library, and the Web of Science for randomized controlled trials comparing the different anesthetic drugs for noncardiac surgery in elderly from inception until July, 2022. The protocol was registered on the PROSPERO database (CRD#42020183014). A total of 34 trials involving 4314 patients undergoing noncardiac surgery in elderly were included. The incidence of POCD for each anesthetic drug was placebo (27.7%), dexmedetomidine (12.9%), ketamine (15.2%), propofol (16.8%), fentanyl (23.9%), midazolam (11.3%), sufentanil (6.3%), sevoflurane (24.0%), and desflurane (28.3%). Pairwise and network meta-analysis showed dexmedetomidine was significantly reducing the incidence of POCD when compared with placebo. Network meta-analysis also suggested dexmedetomidine was significantly reducing the incidence of POCD when compared with sevoflurane. Sufentanil and dexmedetomidine ranked the first and second in reducing the incidence of POCD with the surface under the cumulative ranking curve value of 87.4 and 81.5%. Sufentanil and dexmedetomidine had the greatest possibility to reduce the incidence of POCD for elderly people undergoing noncardiac surgery.

Tau protein plays a role in the mechanism of cognitive disorders induced by anesthetic drugs

Cognitive disorders are mental health disorders that can affect cognitive ability. Surgery and anesthesia have been proposed to increase the incidence of cognitive dysfunction, including declines in memory, learning, attention and executive function. Tau protein is a microtubule-associated protein located in the axons of neurons and is important for microtubule assembly and stability; its biological function is mainly regulated by phosphorylation. Phosphorylated tau protein has been associated with cognitive dysfunction mediated by disrupting the stability of the microtubule structure. There is an increasing consensus that anesthetic drugs can cause cognitive impairment. Herein, we reviewed the latest literature and compared the relationship between tau protein and cognitive impairment caused by different anesthetics. Our results substantiated that tau protein phosphorylation is essential in cognitive dysfunction caused by anesthetic drugs, and the possible mechanism can be summarized as "anesthetic drugs-kinase/phosphatase-p-Tau-cognitive impairment".

Amelioratory Effect of Melatonin on Cognition Dysfunction Induced by Sevoflurane Anesthesia in Aged Mice

Background

Postoperative cognitive dysfunction (POCD) can be described as a clinical phenomenon characterized by cognitive impairment in patients, particularly elderly patients, after anesthesia and surgery. Researchers have focused on the probable effect of general anesthesia drugs on cognitive functioning status in older adults. Melatonin is an indole-type neuroendocrine hormone with broad biological activity and potent anti-inflammatory, anti-apoptotic, and neuroprotective effects. This study investigated the effects of melatonin on cognitive behavior in aged mice anesthetized with sevoflurane. In addition, melatonin's molecular mechanism was determined.

Objectives

This study aimed to investigate the mechanisms of melatonin against sevoflurane-induced neurotoxicity.

Methods

A total of 94 aged C57BL/6J mice were categorized into different groups, namely control (control + melatonin (10 mg/kg)), sevoflurane (sevoflurane + melatonin (10 mg/kg)), sevoflurane + melatonin (10 mg/kg) + phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) inhibitor LY294002 (30 mg/kg), and sevoflurane + melatonin (10 mg/kg) + mammalian target of rapamycin (mTOR) inhibitor (10 mg/kg). The open field and Morris water maze tests were utilized to assess the neuroprotective effects of melatonin on sevoflurane-induced cognitive impairment in aged mice. The expression levels of the apoptosis-linked proteins, PI3K/Akt/mTOR signaling pathway, and pro-inflammatory cytokines in the brain's hippocampus region were determined using the Western blotting technique. The apoptosis of the hippocampal neurons was observed using the hematoxylin and eosin staining technique.

Results

Neurological deficits in aged, sevoflurane-exposed mice were significantly decreased after melatonin treatment. Mechanistically, melatonin treatment restored sevoflurane-induced down-regulated PI3K/Akt/mTOR expression and significantly attenuated sevoflurane-induced apoptotic cells and neuroinflammation.

Conclusions

The findings of this study have highlighted the neuroprotective effect of melatonin on sevoflurane-induced cognitive impairment via regulating the PI3K/Akt/mTOR pathway, which might be effective in the clinical treatment of elderly patients with anesthesia-induced POCD.

A novel predictive strategy for the incidence of postoperative neurocognitive dysfunction in elderly patients with mild cognitive impairment

Objective: Preoperative levels of cognition-related biomarkers and intraoperative cerebral ischemia and hypoxia might cause postoperative neurocognitive dysfunction (PND). The aim of this study was to evaluate the predictive ability of preoperative plasma biomarkers along with cerebral oxygen saturation (SctO₂) for the incidence of PND in elderly patients with mild cognitive impairment (MCI).

Methods: A total of 210 patients aged 65–80 years undergoing spinal surgery were randomly assigned to three groups (n = 70 each): propofol, sevoflurane, and propofol/sevoflurane as anesthesia maintenance protocols. Propofol was administrated target-controlled infusion of 4 μg/ml (group P), the minimum alveolar concentration (MAC) of inhalation anesthetic sevoflurane was 1.3 (group S), and propofol was injected with a target-controlled plasma concentration of 1.2 μg/ml, accompanied by sevoflurane inhalation 0.7 MAC (group PS). Cognitive function was evaluated 1 day preoperatively and on the 7th day postoperatively. Preoperative levels of amyloidβ-40 (Aβ-40), Aβ-42, total tau protein (T-tau), phosphorylated tau protein (P-tau), and triggering receptors on myeloid cells-2 (TREM2) were investigated. SctO₂ was monitored intraoperatively.

Results: Aβ-42 had the strongest significant correlation with preoperative MoCA score. The value of Aβ-42 associated with a high risk of PND was 28.34 pg/ml, and the area under the curve (AUC) was predicted to be 0.711. When the preoperative level of Aβ-42 was 28.34 pg/ml, SctO_2max% was 9.92%. The AUC was predicted to be 0.872, and the sensitivity and specificity were 0.833 and 0.841, respectively.

Conclusion: Under the conditions of preoperative Aβ-42 less than 28.34 pg/ml, the intraoperative fluctuation range of cerebral oxygen saturation should be maintained within 9.92% to reduce the occurrence of PND in geriatric patients with MCI.

Effects of Sevoflurane Anesthesia on Cerebral Lipid Metabolism in the Aged Brain of Marmosets and Mice

Objective

In the lipid-rich brain, lipids performed signaling processes associated with the control system of the cell cycle, stress, and inflammatory reactions, as well as maintained brain and cellular homeostasis. The effects of general anesthesia on brain impairment in the elderly were controversial and complex. The study sought to evaluate the effect of lipid metabolism in the brain of aged marmosets and mice under long-term exposure to sevoflurane.

Methods

A total of 6 marmosets over 8-year-old and 10 mice aged 18 months were divided into the sevoflurane anesthesia and control groups, respectively. Marmosets in the sevoflurane anesthesia group were exposed to 1.5–2.5% sevoflurane and 100% O₂ for 6 h. Mice anesthetized with sevoflurane were exposed to 3% sevoflurane and 60% O₂ for 6 h. All prefrontal cortex tissues of marmosets and mice were harvested for the analysis of lipidomics.

Results

Compared to the control group, we found that phosphatidylethanolamine (PE) (18:0/22:5), PE (16:0/22:5), PE (18:2/22:5), PE (14:0/22:5), and PE (18:1/22:5) increased in the prefrontal cortex of marmosets in the sevoflurane group, while triglyceride (TAG)56:5-fatty acid (FA) 20:4, TAG58:10-FA22:6, and TAG60:10-FA22:6 decreased. For aged mice, we indicated that lipid components phosphatidic acid (PA) (18:1/20:2) and TAG52:5-FA20:4 in the sevoflurane group increased, but PE (14:0/22:4), diglyceride (DAG) (16:1/18:2), and lysophosphatidylcholine (LPC) (16:1) + AcO decreased. More deeply, sevoflurane anesthesia resulted in the presence of 70 specific lipids in mice and marmosets. The enriched lipid subclasses were mainly monoacylglycerophosphoethanolamines and five other subclasses.

Conclusion

Sevoflurane caused slight changes in lipid metabolism both in the aged brain of marmosets and mice. However, the pathways of lipid metabolism were not affected. The effects of sevoflurane on lipid metabolism in aged brains may differ among species.

The Effect of Propofol versus Sevoflurane on Postoperative Delirium in Parkinson's Disease Patients Undergoing Deep Brain Stimulation Surgery: An Observational Study

BACKGROUND

The selection of the maintenance of general anesthesia may affect the development of postoperative delirium (POD), notably for Parkinson's disease (PD) patients, due to their lower cognitive reserve. The present study was designed to compare the potential impact of propofol vs. sevoflurane based general anesthesia maintenance methods on the development of POD in PD patients following deep brain stimulation (DBS) surgery.

METHODS

A total of 125 PD patients who were scheduled to undergo DBS surgery were randomly divided into the propofol (n = 63) and the sevoflurane groups (n = 62). The patients in the two groups randomly received propofol- or sevoflurane-based general anesthesia. The Confusion Assessment Method (CAM) was employed by an investigator who was blinded to the anesthesia regimen and was administered twice per day from postoperative day 1 until discharge.

RESULTS

The incidence of POD was 22.22% (14/63) with propofol anesthesia and 20.97% (13/62) with sevoflurane anesthesia (p = 0.865). In addition, no difference was noted in the duration and severity of delirium between the propofol and sevoflurane groups.

CONCLUSIONS

In the present study, propofol- and sevoflurane-based general anesthesia exhibited comparable results with regard to the POD incidence in PD patients undergoing deep brain stimulation surgery.

Comparison of Intravenous and Inhalational Anesthetic on Postoperative Cognitive Outcomes in Elderly Patients Undergoing Cancer Surgery: Systematic Review and Meta-analysis

PURPOSE

Previous studies have documented consistent findings on the long-term cognitive effects such as postoperative cognitive dysfunction (POCD), delirium and delayed recovery among elderly undergoing cancer surgery. This review was conducted to compare the effect of intravenous and inhalational anesthetic on the postoperative cognitive outcomes among elderly patients undergoing cancer surgery.

DESIGN

Systematic review and meta-analysis METHODS: We searched Medline, EMBASE, PubMed Central, ScienceDirect, Google Scholar, and Cochrane library from inception until May 2021. We carried out a meta-analysis with a random-effects model and reported pooled risk ratio (RR) or standardized mean difference (SMD) with 95% confidence interval (CI) depending on the type of outcome.

FINDINGS

In total, we analyzed 10 studies including 2,333 participants. Half of the studies had high risk of bias. For the cognitive score, the pooled SMD was -0.87 [95% CI: -3.97 to 2.24] indicating no statistically significant difference between inhalational and intravenous anesthetic. For POCD, the pooled RR was 1.24 (95% CI: 0.83-1.84); for postoperative delirium, the pooled RR was 2.26 (95% CI: 0.79-6.44); for delayed neurocognitive recovery, the pooled RR was 1.49 (95% CI: 1.09-2.03).

CONCLUSION

Inhalational anesthetics did not show a significant difference in postoperative cognitive outcomes, except delayed neurocognitive recovery, compared to intravenous anesthetic following cancer surgery.

Incidence of Postoperative Cognitive Dysfunction Following Inhalational vs Total Intravenous General Anesthesia: A Systematic Review and Meta-Analysis

Postoperative cognitive dysfunction (POCD) has been increasingly recognized as a contributor to postoperative complications. A consensus-working group recommended that POCD should be distinguished between delayed cognitive recovery, ie, evaluations up to 30 days postoperative, and neurocognitive disorder, ie, assessments performed between 30 days and 12 months after surgery. Additionally, the choice of the anesthetic, either inhalational or total intravenous anesthesia (TIVA) and its effect on the incidence of POCD, has become a focus of research. Our primary objective was to search the literature and conduct a meta-analysis to verify whether the choice of general anesthesia may impact the incidence of POCD in the first 30 days postoperatively. As a secondary objective, a systematic review of the literature was conducted to estimate the effects of the anesthetic on POCD between 30 days and 12 months postoperative. For the primary objective, an initial review of 1913 articles yielded ten studies with a total of 3390 individuals. For the secondary objective, four studies with a total of 480 patients were selected. In the first 30 days postoperative, the odds-ratio for POCD in TIVA group was 0.46 (95% CI = 0.26-0.81; p = 0.01), compared to the inhalational group. TIVA was associated with a lower incidence of POCD in the first 30 days postoperatively. Regarding the secondary objective, due to the small number of selected articles and its high heterogeneity, a metanalysis was not conducted. Given the heterogeneity of criteria for POCD, future prospective studies with more robust designs should be performed to fully address this question.

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.

Medicolegal Implications of Mild Neurocognitive Disorder

INTRODUCTION

The syndromes of mild cognitive impairment (MCI) or mild neurocognitive disorder (MiND), often prodromal to dementia (Major Neurocognitive Disorder), are characterized by acquired clinically significant changes in one or more cognitive domains despite preserved independence. Mild impairment has significant medicolegal consequences for an affected person and their care system. We review the more common etiologies of MiND and provide a systematic review of its medicolegal implications.

METHODS

We conducted a systematic review of the peer-reviewed English literature on medicolegal aspects of MCI or MiND using comprehensive search terms and expanding our review to include sources cited by these reports.

RESULTS

Impairment of memory, executive function, social cognition, judgment, insight or abstraction can alter an individual's abilities in a variety of areas that include decision making, informed consent, designation of a surrogate decision-maker such as a health care proxy, understanding and management of financial affairs, execution of a will, or safe driving.

CONCLUSION

Even mild cognitive impairment can have significant behavioral consequences. Clinicians can assist care partners and persons with MCI or MiND by alerting them to the medicolegal concerns that often accompany cognitive decline. Early recognition and discussion can help a care system manage medicolegal risk more effectively and promote thoughtful advance planning.

Effects of inhalation and propofol anaesthesia on postoperative cognitive dysfunction in elderly noncardiac surgical patients: A systematic review and meta-analysis

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a very common event in elderly noncardiac surgical patients. The effects of inhalational anaesthetics and propofol on the incidence of POCD and postoperative cognitive status at different time points after surgery are currently unclear.

METHODS

We searched the Embase, Medline, Cochrane Library, and Web of Science databases for randomized controlled trials (RCTs), in which inhalation anaesthesia and propofol anaesthesia were compared. The incidence of POCD or postoperative cognitive status was assessed in elderly patients undergoing noncardiac surgery.

RESULTS

Fifteen RCTs with 1854 patients were included in this meta-analysis. The incidence of POCD on postoperative Days 2-6 after propofol anaesthesia was markedly lower than that after inhalation anaesthesia (risk ratio (RR): 0.37, 95% confidence interval (CI): 0.15-0.88, P = .025), and Mini-Mental State Examination (MMSE) scores after propofol anaesthesia were substantially higher than those after inhalation anaesthesia (standard mean difference (SMD): 0.59, 95% CI: 0.07-1.11, P = .026). The levels of interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) were much lower after propofol anaesthesia than after inhalation anaesthesia (SMD: -2.027, 95% CI: -3.748- -0.307, P = .021; SMD: -0.68, 95% CI: -0.93- -0.43, P < .001).

CONCLUSIONS

The moderate evidence from this meta-analysis shows that, in elderly noncardiac surgical patients, propofol anaesthesia is superior to inhalation anaesthesia for attenuating of early POCD incidence, and low-level evidence shows that cognitive status is higher and systemic inflammation is less severe after propofol anaesthesia in the early days after surgery.

LIMITATIONS

The sample size was not sufficiently large for systemic inflammation, and the tools to identify POCD were not uniform in the included studies.

Lovastatin attenuates sevoflurane-induced cognitive disorder in aged rats via reducing Aβ accumulation

As a general anesthetic widely used in surgical, sevoflurane has been shown to cause cognitive and memory deficits in the elderly. It's important to find out agents that can counteract sevoflurane-induced cognitive dysfunction. This study is aimed to investigate the effect of lovastatin on sevoflurane-induced cognitive impairment in aged rats and reveal the potential mechanisms. BV-2 cells, rat hippocampal neurons or male aged rats were exposed to 2% sevoflurane for 5 h. The cells were pretreated with 10 μM lovastatin. The rats were intraperitoneally injected with 5 mg/kg/day lovastatin for three days. The results showed that lovastatin enhanced exosomal IDE secretion from sevoflurane-exposed BV-2 cells and promoted Aβ degradation. Lovastatin treatment also inhibited the increased expressions of β-secretase 1 (BACE1) and γ-secretase in hippocampal neurons under sevoflurane exposure in vitro. In animal experiments, the discrimination index in novel object recognition test and percentage of spontaneous alternation in Y-maze test were significantly elevated after lovastatin administration. In addition, Aβ plaque area and contents of soluble Aβ1-40 and Aβ1-42 in the hippocampal tissues were decreased upon lovastatin treatment. Furthermore, lovastatin reversed sevoflurane-induced Aβ accumulation via up-regulating IDE expression, and down-regulating amyloid precursor protein (APP)-related protein expression (β-C-terminal fragment (CTF), BACE1 and γ-secretase). In conclusion, lovastatin alleviates sevoflurane-induced cognitive deficient in aged rats via promoting Aβ degradation and reducing Aβ production. Lovastatin may be beneficial in preventing anesthetic-induced cognitive impairment.

Association Between Anesthesia Delivered During Tumor Resection and Cancer Survival: a Systematic Review of a Mixed Picture with Constant Themes

BACKGROUND

Surgery is required for cure of most solid tumors, and general anesthesia is required for most cancer surgery. The vast majority of cancer surgery is facilitated by general anesthesia using volatile inhalational agents such as isoflurane and sevoflurane. Only recently have the immunologic and oncologic effect of inhalational agents, and their alternative, propofol-based total intravenous anesthesia (TIVA), come under investigation.

METHODS

Between January 2019 and June 2020, English language articles on PubMed were searched for the keywords "Propofol" "TIVA" or "IV anesthesia" and either "cancer surgery" or "surgical oncology." Duplicates were removes, manuscripts classified as either in vitro, animal, translational, or clinical studies, and their results summarized within these categories.

RESULTS

In-vitro and translational data suggest that inhalational anesthetics are potent immunosuppressive and tumorigenic agents that promote metastasis, while propofol is anti-inflammatory, anti-tumorigenic, and prevents metastasis development. Clinically there is a recurring association, based largely on retrospective, single institution series, that TIVA is associated with significant improvements in disease-free interval and overall survival in a number of, but not all, solid tumors. The longer the surgery is, the more intense the surgical trauma is, the more aggressive the malignancy is, and the higher likelihood of an association is.

DISCUSSION

Prospective randomized trials, coupled with basic science and translational studies, are needed to further define this association.

Develop a Clinical Prediction Model for Postoperative Cognitive Dysfunction after Major Noncardiac Surgery in Elderly Patients: A Protocol for a Prospective Observational Study

Perioperative neurocognitive disorders (PNDs) refer to cognitive decline identified in the preoperative or postoperative period. It has been reported that the incidence of postoperative neurocognitive impairment after noncardiac surgery in patients older than 65 at 1 week was 25.8∼41.4%, and at 3 months 9.9∼12.7%. PNDs will last months or even develop to permanent dementia, leading to prolonged hospital stays, reduced quality of life, and increased mortality within 1 year. Despite the high incidence and poor prognosis of PNDs in the aged population, no effective clinical prediction model has been established to predict postoperative cognitive decline preoperatively. To develop a clinical prediction model for postoperative neurocognitive dysfunction, a prospective observational study (Clinical trial registration number: ChiCTR2000036304) will be performed in the Shanghai General Hospital during January 2021 to October 2022. A sample size of 675 patients aged >65 years old, male or female, and scheduled for elective major noncardiac surgery will be recruited. A battery of neuropsychological tests will be used to test the cognitive function of patients at 1 week, 1 month, and 3 months postoperatively. We will evaluate the associations of PNDs with a bunch of candidate predictors including general characteristics of patients, blood biomarkers, indices associated with anesthesia and surgery, retinal nerve-fiber layer thickness, and frailty index to develop the clinical prediction model by using multiple logistic regression analysis and least absolute shrinkage and the selection operator (LASSO) method. The k-fold cross-validation method will be utilized to validate the clinical prediction model. In conclusion, this study was aimed to develop a clinical prediction model for postoperative cognitive dysfunction of old patients. It is anticipated that the knowledge gained from this study will facilitate clinical decision-making for anesthetists and surgeons managing the aged patients undergoing noncardiac surgery.

The Effects of Propofol and Sevoflurane on Postoperative Delirium in Older Patients: A Randomized Clinical Trial Study

BACKGROUND

Postoperative delirium is associated with adverse postoperative outcomes. However, whether intravenous and inhalation anesthetics are associated with different risks of postoperative delirium remains unknown.

OBJECTIVE

We set up to determine the incidence and duration of postoperative delirium in older patients who had surgery under the intravenous anesthetic propofol or the inhalational anesthetic sevoflurane.

METHODS

Participants were patients who had total hip/knee replacements and were randomized to propofol (N = 106) or sevoflurane (N = 103) anesthesia group. The Confusion Assessment Method was employed by investigators who were blinded to the anesthesia regimen to assess the incidence and duration (days of postoperative delirium per person) of postoperative delirium on postoperative days 1, 2, and 3.

RESULTS

A total of 209 participants (71.2±6.7 years old, 29.2% male) were included in the final data analysis. The incidence of postoperative delirium was 33.0% with propofol anesthesia and 23.3% with sevoflurane anesthesia (p = 0.119, Chi-square test), and we estimated that we would need 316 participants in each arm to detect a potential statistically significant difference. Days of postoperative delirium per person were higher in the propofol (0.5±0.8) anesthesia group compared to the sevoflurane anesthesia group (0.3±0.5, p = 0.049, Student's t-test).

CONCLUSION

This pilot study established a system to compare effects of different anesthetics and generated a hypothesis that propofol trended to have a higher incidence and had longer duration of postoperative delirium than sevoflurane. Additional studies with a larger sample size are needed to test this hypothesis.

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

[Postoperative cognitive disorder]

Cognitive impairment or delirium occurs in about 40% of elderly patients after surgery. The increasing number of elderly people has led to a significant increase in the number of cases of postoperative cognitive dysfunction (POCD). This is one of the most important medical and social problems, the analysis of which is especially difficult, since it requires the coordination of a large number of specialties: anesthesiology, surgery, neurology, psychiatry, neuropsychology, as well as fundamental neurosciences. Thus, a systematic multidisciplinary approach that takes into account all possible factors affecting the condition of patients should be considered. The article is devoted to the main aspects of the pathogenesis, prevention and treatment of POCD.

Effects of different anesthesia and analgesia on cellular immunity and cognitive function of patients after surgery for esophageal cancer

BACKGROUND

The study intends to analyze influences of different anesthesia and analgesia on cellular immune and cognitive functions of patients undergoing thoracotomy for esophageal cancer (EsC).

METHODS

Patients undergoing thoracotomy for EsC were divided into four groups: Group A (received general anesthesia [GA]) and postoperative intravenous analgesia); B (received GA and postoperative epidural analgesia); C (received GA combined with thoracic epidural anesthesia [TEA]) and postoperative intravenous analgesia); D (received GA combined with TEA and postoperative epidural analgesia). The T-lymphocyte subsets were determined at 30 min before anesthesia induction (T<inf>0</inf>), 2 h after skin incision (T<inf>1</inf>), and at 4 h (T<inf>2</inf>), 24 h (T<inf>3</inf>), and 48 h (T<inf>4</inf>) after operation. Besides, visual analogue scale (VAS) and mini-mental state examination (MMSE) were assessed.

RESULTS

The percentage of CD3⁺ and CD4⁺ cells in groups B and C were higher than group A from T<inf>1</inf> to T<inf>3</inf>. The ratio of CD4⁺/CD8⁺ in group B and C were higher than in group A at T<inf>3</inf>. Compared with group A, group D had increased percentages of CD3⁺ and CD4⁺ from T<inf>1</inf> to T<inf>4</inf>, and elevated ratio of CD4⁺/CD8⁺ from T<inf>2</inf> to T<inf>4</inf> VAS scores were lower and MMSE scores were higher in groups B, C, and D than in group A, and group D had relatively lower VAS and higher MMSE scores as compared to group B.

CONCLUSIONS

The intraoperative general anesthesia combined with thoracic epidural anesthesia and postoperative epidural analgesia may reduce adverse effect on cellular immune and cognitive functions of patients undergoing thoracotomy for EsC.

A New Rat Model of Chronic Cerebral Hypoperfusion Resulting in Early-Stage Vascular Cognitive Impairment

Objective

Currently, most models of vascular cognitive impairment are established by occluding the carotid arteries uni- or bilaterally to reduce the cerebral blood flow mimicking chronic cerebral hypoxia. Due to the sudden blood flow interruption, a gradual narrowing of the carotid artery cannot be completely imitated. This paper aims to establish a bilateral carotid stenosis model with mild cognitive dysfunction and mild white matter changes to simulate patients with vascular predementia.

Methods

Aged Wistar rats (18 months old) underwent either bilateral common carotid artery stenosis (BCAS) or occlusion (BCAO) surgery or a sham operation (control group). The cerebral blood flow in the frontal cortex was measured using Doppler flowmetry. Thirty days after surgery, cognitive function impairments were determined with the Morris water maze; cerebral magnetic resonance imaging was performed to detect changes in fractional anisotropy to assess white matter injuries, and histological studies were performed.

Results

The aged rats in the BCAS group showed a more gradual cerebral blood flow reduction and a lower mortality rate (11%) compared to rats in the BCAO group. The water maze test revealed a more marginal impairment affecting spatial learning and memory in rats with BCAS than in rats with BCAO. Diffusion tensor imaging detected white matter injuries in the hippocampus and cerebral cortex of BCAS rats. Particularly, a small portion of nerve fibers of the lateral somatosensory cortex was significantly different between rats of the BCAO and BCAS groups. In the BCAS group, the microscopic structure of the hippocampal CA1 region changed slightly after 30 days and sustained a slight mitochondrial crista crack. Fluorescence staining indicated that the number of GFAP-positive cells was increased in rat brains of the BCAS group, and this phenomenon was even more pronounced in the BCAO group. The hnRNPA2/B1 and GABA_AR-α1 expression levels were significantly decreased in the hippocampus of rats with BCAS compared to those of controls.

Conclusion

Severe bilateral carotid stenosis induced mild cognitive dysfunction and slight structural changes in the brains of aged rats. Thus, a chronic cerebral hypoperfusion model was successfully established.

Impact of Sevoflurane Versus Propofol Anesthesia on Post-Operative Cognitive Dysfunction in Elderly Cancer Patients: A Double-Blinded Randomized Controlled Trial

Background

Research on the clinical outcomes of surgical patients anaesthetized with sevoflurane and the association of sevoflurane with post-operative cognitive dysfunction (POCD) is scarce. We evaluated whether sevoflurane-based anesthesia increased the incidence of POCD and worsened prognosis compared to propofol-based anesthesia in elderly cancer patients.

Material/Methods

This single-center, prospective, double-blind randomized controlled trial included 234 patients aged 65 to 86 years undergoing tumor resection who received sevoflurane-based (Group S) or propofol-based (Group P) anesthesia during surgery. A series of neuropsychological tests was performed to evaluate cognitive function before surgery and at 7 days and 3 months post-operation, and the results were compared to those of healthy controls.

Results

At 7 days post-operation there were no significant differences in the incidence of POCD between patients who received sevoflurane-based or propofol-based anesthesia during surgery: Group S was at 29.1% (32 out of 110 patients) versus Group P at 27.3% (30 out of 110), P=0.764. At 3 months, Group S was at 11.3% (12 out of 106 patients) versus Group P at 9.2% (10 out of 109), P=0.604. During the first 2 days post-operation, the QoR-40 global score was significantly lower in Group S compared to Group P [POD 1: P=0.004; POD 2: P=0.001]. There were no significant differences in in-hospital post-operative complications, post-operative length of hospital stay, all-cause mortality at 30 days, and 3 months post-operation, or post-operative quality of life at 3 months between patients in Group S and Group P.

Conclusions

Sevoflurane-based anesthesia did not increase the incidence of POCD compared to propofol-based anesthesia at 7 days or 3 months post-operation or impact short-term post-operative prognosis.

Ampelopsin alleviates sevoflurane-induced cognitive dysfunction by mediating NF-κB pathway in aged rats

BACKGROUND

Cancer-induced bone pain (CIBP) is the pain caused by bone metastasis from malignant tumors, and the largest source of pain for cancer patients. miR-300 is an important miRNA in cancer. It has been shown that miR-300 regulates tumorigenesis of various tumors.

PURPOSE

This study aims to investigate the role of miR-300 in CIBP and its underlying molecular mechanisms in vitro and in vivo.

METHODS

We constructed CIBP model in rats and investigated the mechanism through which miR-300 affects CIBP. We first examined expression level of miR-300 in CIBP rats and then tested the effect of its overexpression. Next, we identified the target of miR-300 using TargetScan analysis and double luciferase assay. Finally, we studied genetic interactions between miR-300 and its target and their roles in CIBP.

RESULTS

We found that miR-300 was downregulated in CIBP rats. Overexpression of miR-300 significantly attenuated cancer-induced neuropathic pain (p < 0.01). Furthermore, TargetScan analysis and double luciferase assay show High Mobility Group Box 1 (HMGB1) is a target of miR-300. Notably, HMGB1 is overexpressed in CIBP rats, while up-regulation of miR-300 significantly suppresses expression of HMGB1 (p < 0.01). Moreover, knockdown of HMGB1 by siRNA significantly relieves cancer-induced neuropathic pain in rats (p < 0.01). On the other hand, HMGB1 overexpression partially blocked the effect of miR-300 on cancer-induced nerve pain.

CONCLUSION

miR-300 relieves cancer-induced neuropathic pain by inhibiting HMGB1 expression. These results may be beneficial for the treatment of CIBP in clinical practice.

Anesthetic management of geriatric patients

The number of elderly patients who frequently access health care services is increasing worldwide. While anesthesiologists are developing the expertise to care for these elderly patients, areas of concern remain. We conducted a comprehensive search of major international databases (PubMed, Embase, and Cochrane) and a Korean database (KoreaMed) to review preoperative considerations, intraoperative management, and postoperative problems when anesthetizing elderly patients. Preoperative preparation of elderly patients included functional assessment to identify preexisting cognitive impairment or cardiopulmonary reserve, depression, frailty, nutrition, polypharmacy, and anticoagulation issues. Intraoperative management included anesthetic mode and pharmacology, monitoring, intravenous fluid or transfusion management, lung-protective ventilation, and prevention of hypothermia. Postoperative checklists included perioperative analgesia, postoperative delirium and cognitive dysfunction, and other complications. A higher level of perioperative care was required for older surgical patients, as multiple chronic diseases often makes them prone to developing postoperative complications, including functional decline and loss of independence. Although the guiding evidence remains poor so far, elderly patients have to be provided optimal perioperative care through close interdisciplinary, interprofessional, and cross-sectional collaboration to minimize unwanted postoperative outcomes. Furthermore, along with adequate anesthetic care, well-planned postoperative care should begin immediately after surgery and extend until discharge.

General Anesthetic Use in Fragile X Spectrum Disorders

The fragile X premutation is characterized by a repeat expansion mutation (between 55 to 200 CGG repeats) in the fragile X mental retardation 1 (FMR1) gene, which leads to RNA toxicity at the cellular level. This may cause patients with the premutation to be particularly susceptible to environmental toxins, which could manifest clinically as new or worsening ataxia and memory loss. Multiple published case reports have also suggested general anesthetics as a potential toxin leading to negative side effects when used in patients with fragile X-associated disorders. However, at this time, there have been no formal research studies regarding cellular changes or long-term clinical manifestations after general anesthetic use in this population. This review aims to highlight previous case reports regarding sequelae related to general anesthetic use in fragile X-associated disorders. New case reports related to this phenomenon are also included.

Postoperative cognitive dysfunction after sevoflurane or propofol general anaesthesia in combination with spinal anaesthesia for hip arthroplasty

It is unknown if the type of general anaesthetic used for maintenance of anaesthesia affects the incidence of postoperative cognitive dysfunction (POCD). The aim of this study was to compare the incidence of POCD in patients administered either sevoflurane or propofol for maintenance of anaesthesia during total hip replacement surgery. Following administration of a spinal anaesthetic, patients received either sevoflurane (n=121) or propofol (n=171) at the discretion of the anaesthetist for maintenance of general anaesthesia to maintain the processed electroencephalogram (bispectral index, BIS) under 60. POCD was assessed postoperatively at day 7, three months, and 12 months using a neurocognitive test battery. There was no statistically significant difference between the incidence of POCD at any timepoint with sevoflurane compared to propofol. The mean BIS was significantly lower in the sevoflurane group than in the propofol group (mean BIS 44.3 [standard deviation, SD 7.5] in the sevoflurane group versus 53.7 [SD 8.1] in the propofol group, <i>P</i>=0.0001). However, there was no statistically significant association between intraoperative BIS level and the incidence of POCD at any timepoint. Our results suggest that the incidence of POCD is not strongly influenced by the type of anaesthesia used in elderly patients.

Effects of propofol and surgery on neuropathology and cognition in the 3xTgAD Alzheimer transgenic mouse model

Background

Previous work suggests that anaesthesia and surgery amplify the pathology and cognitive impairment of animals made vulnerable via age or specific transgenes. We hypothesized that surgery under propofol anaesthesia, a widely used i.v. general anaesthetic, has minimal delayed cognitive and neuroinflammatory sequelae in a vulnerable mouse transgenic model.

Methods

We conducted caecal ligation and excision surgery in cognitively presymptomatic (11-month-old) 3xTgAD mice under i.p. propofol anaesthesia. Age-matched 3xTgAD control mice received vehicle or propofol without surgery. Morris water maze testing was conducted 3 and 15 weeks later. Brains were examined with quantitative immunohistochemistry for amyloid β plaques, tau pathology, and microglial activation. Acute changes in neuroinflammatory cytokines were assessed in separate cohorts at 6 h.

Results

We detected no significant differences between groups in escape latencies at either 3 or 15 weeks, but detected a significant effect of surgery in the probe test at both 3 and 15 weeks. Spatial working memory was unaffected at 16 weeks in any group. No effects of either propofol alone or propofol with surgery were detected on plaque formation, tau aggregates, or neuroinflammation. Acute biochemical assays detected no effects in brain interleukin-10 or interleukin-6 concentrations.

Conclusions

Surgery in a vulnerable transgenic mouse under propofol anaesthesia was associated with minimal to no changes in short- and long-term behaviour and no changes in neuropathology. This suggests that propofol anaesthesia is associated with better cognitive outcomes in the aged, vulnerable brain compared with inhalation anaesthesia.

(‑)Epigallocatechin‑3‑gallate attenuates anesthesia‑induced memory deficit in young mice via modulation of nitric oxide expression

(−)Epigallocatechin-3-gallate (EGCG) is a type of polyphenol monomer and is the predominant component of catechin compounds extractable from green tea. Previous studies have demonstrated that EGCG exhibits numerous bioactivities both in vitro and in vivo, including antitumor, antioxidant and anti-inflammatory activities, as well as lowering blood lipid levels and protecting against radiation. The present study aimed to investigate whether administration of EGCG may attenuate anesthesia-induced memory deficit in young mice and to reveal the associated underlying mechanisms. The present study revealed that EGCG administration significantly attenuated memory deficit, oxidative stress and cell apoptosis exhibited by anesthesia-induced mice, as determined by Morris water maze testing and ELISA analysis. Furthermore, the results of ELISA and western blot analysis demonstrated that EGCG administration restored acetylcholinesterase activity and modulated the expression levels of neuronal nitric oxide synthase (nNOS), β-amyloid and amyloid precursor protein in anesthesia-induced mice. The present study also employed L-arginine as an nNOS substrate and 7-nitroindazole as an nNOS inhibitor, which were demonstrated to inhibit or potentiate the effects of EGCG, respectively, on anesthesia-induced memory deficit in mice. Therefore, the present study demonstrated that the administration of EGCG attenuated anesthesia-induced memory deficit in young mice, potentially via the modulation of nitric oxide expression and oxidative stress.

Intravenous versus inhalational maintenance of anaesthesia for postoperative cognitive outcomes in elderly people undergoing non-cardiac surgery

BACKGROUND

The use of anaesthetics in the elderly surgical population (more than 60 years of age) is increasing. Postoperative delirium, an acute condition characterized by reduced awareness of the environment and a disturbance in attention, typically occurs between 24 and 72 hours after surgery and can affect up to 60% of elderly surgical patients. Postoperative cognitive dysfunction (POCD) is a new-onset of cognitive impairment which may persist for weeks or months after surgery.Traditionally, surgical anaesthesia has been maintained with inhalational agents. End-tidal concentrations require adjustment to balance the risks of accidental awareness and excessive dosing in elderly people. As an alternative, propofol-based total intravenous anaesthesia (TIVA) offers a more rapid recovery and reduces postoperative nausea and vomiting. Using TIVA with a target controlled infusion (TCI) allows plasma and effect-site concentrations to be calculated using an algorithm based on age, gender, weight and height of the patient.TIVA is a viable alternative to inhalational maintenance agents for surgical anaesthesia in elderly people. However, in terms of postoperative cognitive outcomes, the optimal technique is unknown.

OBJECTIVES

To compare maintenance of general anaesthesia for elderly people undergoing non-cardiac surgery using propofol-based TIVA or inhalational anaesthesia on postoperative cognitive function, mortality, risk of hypotension, length of stay in the postanaesthesia care unit (PACU), and hospital stay.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 11), MEDLINE (1946 to November 2017), Embase (1974 to November 2017), PsycINFO (1887 to November 2017). We searched clinical trials registers for ongoing studies, and conducted backward and forward citation searching of relevant articles.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) with participants over 60 years of age scheduled for non-cardiac surgery under general anaesthesia. We planned to also include quasi-randomized trials. We compared maintenance of anaesthesia with propofol-based TIVA versus inhalational maintenance of anaesthesia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, extracted data, assessed risk of bias, and synthesized findings.

MAIN RESULTS

We included 28 RCTs with 4507 randomized participants undergoing different types of surgery (predominantly cardiovascular, laparoscopic, abdominal, orthopaedic and ophthalmic procedures). We found no quasi-randomized trials. Four studies are awaiting classification because we had insufficient information to assess eligibility.All studies compared maintenance with propofol-based TIVA versus inhalational maintenance of anaesthesia. Six studies were multi-arm and included additional TIVA groups, additional inhalational maintenance or both. Inhalational maintenance agents included sevoflurane (19 studies), isoflurane (eight studies), and desflurane (three studies), and was not specified in one study (reported as an abstract). Some studies also reported use of epidural analgesia/anaesthesia, fentanyl and remifentanil.We found insufficient reporting of randomization methods in many studies and all studies were at high risk of performance bias because it was not feasible to blind anaesthetists to study groups. Thirteen studies described blinding of outcome assessors. Three studies had a high of risk of attrition bias, and we noted differences in the use of analgesics between groups in six studies, and differences in baseline characteristics in five studies. Few studies reported clinical trials registration, which prevented assessment of risk of selective reporting bias.We found no evidence of a difference in incidences of postoperative delirium according to type of anaesthetic maintenance agents (odds ratio (OR) 0.59, 95% confidence interval (CI) 0.15 to 2.26; 321 participants; five studies; very low-certainty evidence); we noted during sensitivity analysis that using different time points in one study may influence direction of this result. Thirteen studies (3215 participants) reported POCD, and of these, six studies reported data that could not be pooled; we noted no difference in scores of POCD in four of these and in one study, data were at a time point incomparable to other studies. We excluded one large study from meta-analysis because study investigators had used non-standard anaesthetic management and this study was not methodologically comparable to other studies. We combined data for seven studies and found low-certainty evidence that TIVA may reduce POCD (OR 0.52, 95% CI 0.31 to 0.87; 869 participants).We found no evidence of a difference in mortality at 30 days (OR 1.21, 95% CI 0.33 to 4.45; 271 participants; three studies; very low-certainty evidence). Twelve studies reported intraoperative hypotension. We did not perform meta-analysis for 11 studies for this outcome. We noted visual inconsistencies in these data, which may be explained by possible variation in clinical management and medication used to manage hypotension in each study (downgraded to low-certainty evidence); one study reported data in a format that could not be combined and we noted little or no difference between groups in intraoperative hypotension for this study. Eight studies reported length of stay in the PACU, and we did not perform meta-analysis for seven studies. We noted visual inconsistencies in these data, which may be explained by possible differences in definition of time points for this outcome (downgraded to very low-certainty evidence); data were unclearly reported in one study. We found no evidence of a difference in length of hospital stay according to type of anaesthetic maintenance agent (mean difference (MD) 0 days, 95% CI -1.32 to 1.32; 175 participants; four studies; very low-certainty evidence).We used the GRADE approach to downgrade the certainty of the evidence for each outcome. Reasons for downgrading included: study limitations, because some included studies insufficiently reported randomization methods, had high attrition bias, or high risk of selective reporting bias; imprecision, because we found few studies; inconsistency, because we noted heterogeneity across studies.

AUTHORS' CONCLUSIONS

We are uncertain whether maintenance with propofol-based TIVA or with inhalational agents affect incidences of postoperative delirium, mortality, or length of hospital stay because certainty of the evidence was very low. We found low-certainty evidence that maintenance with propofol-based TIVA may reduce POCD. We were unable to perform meta-analysis for intraoperative hypotension or length of stay in the PACU because of heterogeneity between studies. We identified 11 ongoing studies from clinical trials register searches; inclusion of these studies in future review updates may provide more certainty for the review outcomes.

Effects of intravenous anesthetics on the phosphorylation of cAMP response element‑binding protein in hippocampal slices of adult mice

cAMP response‑element binding protein (CREB) functions in hippocampal synaptic plasticity and memory formation. However, it remains unknown whether intravenous anesthetics modulate CREB. The present study aimed to examine the effects of intravenous anesthetics on CREB phosphorylation in the mouse hippocampus. CREB phosphorylation was examined in hippocampal slices with and without pharmacological or intravenous anesthetics via immunoblotting. In a dose‑response experiment, the concentrations of intravenous anesthetics ranged from 10‑9 to 10‑4 mol/l for 1 h. For the time‑response experiment, these slices were incubated with 5x10‑6 mol/l of propofol for 0, 1, 2, 5, 7, 9, 12, 15, 30 and 60 min. In order to examine whether CREB phosphorylation could be recovered following washing out the propofol, the slices were incubated in plain artificial cerebrospinal fluid at different time durations following 5 min incubation with propofol. Propofol, etomidate, ketamine and midazolam inhibited CREB phosphorylation (P<0.05) in a time‑ and dose‑dependent manner. This inhibition was reversible following the removal of propofol, and was rescued by CREB phosphorylation (P<0.05). The decrease in CREB phosphorylation revealed additive effects with 100 µM of chelerythrine and 20 µM of PD‑98059, and the etomidate‑induced decrease in CREB phosphorylation was blocked by 1 mM of NMDA. However, 0.1 µM of phorbol 12‑myristate 13‑acetate, 50 µM of U 73122, 100 µM of carbachol and 10 µM of MK801 were ineffective in the anesthetic‑induced decrease in CREB phosphorylation. Intravenous anesthetics markedly decreased CREB phosphorylation in the mouse hippocampus, which was most likely via the protein kinase C and mitogen activated protein kinase pathways. This suggests that CREB represents a target for anesthetic action in the brain.

Role of the hippocampal 5-HT1A receptor-mediated cAMP/PKA signalling pathway in sevoflurane-induced cognitivedysfunction in aged rats

Objective

This study aimed to evaluate the role of the hippocampal 5-hydroxytryptamine-1A (5-HT1A)-mediated cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) signalling pathway in sevoflurane-induced cognitive dysfunction in aged rats.

Methods

Sixty 18-month-old Sprague–Dawley rats were divided into the control (n = 30) and experimental (Sev, n = 30) groups. The experimental group inhaled 50% air/oxygen mixture (2 L/min) and 2% sevoflurane for 4 hours. The control group inhaled 50% air/oxygen mixture (2 L/min) for 4 hours. The Morris water maze test was performed The mRNA expression of 5-HT1A receptor, and cAMP PKA, cAMP response element-binding protein (CREB), and phosphorylated CREB (p-CREB) protein expression were determined.

Results

The escape latency and swimming distance were greater, and the number of crossings of the platform location and time spent in the platform quadrant were less in the Sev group compared with the control group. cAMP, PKA, CREB, and p-CREB protein expression was downregulated in the Sev group 1 day after anaesthesia compared with the control group. Hippocampal 5-HT1A receptor mRNA expression was higher 7 days after anaesthesia compared with the control group.

Conclusion

Sevoflurane-induced cognitive dysfunction in aged rats may be related to inhibited expression of the hippocampal 5-HT1A receptor-mediated cAMP/PKA signalling pathway.

Neurocognitive Adverse Effects of Anesthesia in Adults and Children: Gaps in Knowledge

Numerous preclinical and clinical studies investigating the neurodevelopmental and neurocognitive effects of exposure to anesthesia and the combination of anesthesia and surgery have demonstrated histopathological and both temporary and long-term cognitive and behavioral effects at the extremes of the human age spectrum. Increasing coverage in the lay press for both our youngest and oldest patient populations has led to heightened concerns regarding the potential harmful side effects of almost all commonly used anesthetic drug regimens. Although the majority of information regarding anesthetic risks in the developing brain derives from preclinical work in rodents, research involving the aged brain has identified a well-defined postoperative cognitive phenotype in humans. While preclinical and clinical data appear to support some association between anesthesia and surgery and the development of detrimental cognitive changes in both the developing and the aged brain, correlation between anesthesia and surgery and poor neurological outcomes does not imply causation. Given this information, no single anesthetic or group of anesthetics can be recommended over any other in terms of causing or preventing negative neurocognitive outcomes in either population. This review summarizes the growing body of preclinical and clinical literature dedicated to the detrimental effects of anesthesia on both the developing and the aging brain.

Impact of inhalational versus intravenous anaesthesia on early delirium and long-term survival in elderly patients after cancer surgery: study protocol of a multicentre, open-label, and randomised controlled trial

INTRODUCTION

Elderly patients who have solid organ cancer often receive surgery. Some of them may develop delirium after surgery and delirium development is associated with worse outcomes. Furthermore, despite all of the advances in medical care, the long-term survival in cancer patients is far from optimal. Evidences suggest that choice of anaesthetics during surgery, that is, either inhalational or intravenous anaesthetics, may influence outcomes. However, the impact of general anaesthesia type on the occurrence of postoperative delirium is inconclusive. Although retrospective studies suggest that propofol-based intravenous anaesthesia was associated with longer survival after cancer surgery when compared with inhalational anaesthesia, prospective studies as such are still lacking. The purposes of this randomised controlled trial are to test the hypotheses that when compared with sevoflurane-based inhalational anaesthesia, propofol-based intravenous anaesthesia may reduce the incidence of early delirium and prolong long-term survival in elderly patients after major cancer surgery.

METHODS AND ANALYSIS

This is a multicentre, open-label, randomised controlled trial with two parallel arms. 1200 elderly patients (≥65 years but <90 years) who are scheduled to undergo major cancer surgery (with predicted duration ≥2 hours) are randomised to receive either sevoflurane-based inhalational anaesthesia or propofol-based intravenous anaesthesia. Other anaesthetics and supplemental drugs including sedatives, opioids and muscle relaxants are administered in both arms according to routine practice. The primary early outcome is the incidence of 7-day delirium after surgery and the primary long-term outcome is the duration of 3-year survival after surgery.

ETHICS AND DISSEMINATION

The study protocol has been approved by the Clinical Research Ethics Committees of Peking University First Hospital (2015[869]) and all participating centres. The results of early and long-term outcomes will be analysed and reported separately.

TRIAL REGISTRATION NUMBER

ChiCTR-IPR-15006209; NCT02662257; NCT02660411.

Does Propofol Anesthesia Lead to Less Postoperative Pain Compared With Inhalational Anesthesia?: A Systematic Review and Meta-analysis

BACKGROUND

Many studies have compared propofol-based anesthesia with inhalational anesthesia. Results from several studies have shown improved postoperative analgesia after propofol anesthesia, but other studies showed contradictory results. There are no large prospective studies that compare postoperative pain after propofol versus inhalational anesthesia. This meta-analysis was designed to focus on this question.

METHODS

A systematic literature search for randomized controlled trials that compared propofol-based anesthesia with volatile agents-based anesthesia in adults undergoing surgery was conducted. Published data were pooled for the meta-analysis with Review Manager (ie, RevMan). The main outcomes included postoperative pain intensity, opioid consumption, need for rescue analgesics, and time to first analgesia.

RESULTS

Thirty-nine clinical trials with a combined subject population of 4520 patients came within the purview of this meta-analysis. The investigated volatile agents included isoflurane, sevoflurane, and desflurane. Compared with inhalational anesthetics, the propofol use was associated with a reduced postoperative pain intensity at rest at 30 minutes, 1 hour, and 12 hours (mean difference in pain scores, 30 minutes, -0.48 [visual analog scale, 0-10]; 99% confidence interval [CI], -1.07 to 0.12, P = 0.04) and reduced morphine-equivalent consumption 0 to 24 hours postoperatively (mean difference in morphine-equivalent consumption, -2.68 mg; 99% CI, -6.17 to 0.82; P = 0.05). Fewer patients required postoperative rescue analgesics during 0 to 24 hours after surgery under propofol anesthesia (risk ratio, 0.87; 99% CI, 0.74-1.03; P = 0.04). In addition, patients anesthetized with propofol required administration of postoperative analgesia later than those anesthetized with volatiles (mean difference in time to first analgesic administration, 6.12 minutes; 99% CI, 0.02-12.21; P = 0.01). Considering that Z statistic in RevMan 5.3 does not perform optimally in highly heterogeneous samples among groups or many combinations of groups with small sample sizes, a P value of <.01 was considered statistically significant. On the basis of this threshold, none of the aforementioned results are statistically significant.

CONCLUSIONS

The current results are affected by substantial heterogeneity, which makes it difficult to predict significant differences in postoperative pain control between propofol anesthesia and inhalational anesthesia. Further large, randomized controlled trials are needed to corroborate these results and to detect differences (if any) between propofol and inhalational anesthesia on postoperative pain.

A clinical review of inhalation anesthesia with sevoflurane: from early research to emerging topics

A large number of studies during the past two decades have demonstrated the efficacy and safety of sevoflurane across patient populations. Clinical researchers have also investigated the effects of sevoflurane, its hemodynamic characteristics, its potential protective effects on several organ systems, and the incidence of delirium and cognitive deficiency. This review examines the clinical profiles of sevoflurane and other anesthetic agents, and focuses upon emerging topics such as organ protection, postoperative cognitive deficiency and delirium, and novel ways to improve postanesthesia outcomes.

Postoperative Cognitive Dysfunction: Minding the Gaps in Our Knowledge of a Common Postoperative Complication in the Elderly

Postoperative cognitive dysfunction (POCD) is a common complication associated with significant morbidity and mortality in elderly patients. There is much interest in and controversy about POCD, reflected partly in the increasing number of articles published on POCD recently. Recent work suggests surgery may also be associated with cognitive improvement in some patients, termed postoperative cognitive improvement (POCI). As the number of surgeries performed worldwide approaches 250 million per year, optimizing postoperative cognitive function and preventing/treating POCD are major public health issues. In this article, we review the literature on POCD and POCI, and discuss current research challenges in this area.