Methylene blue reduces incidence of early postoperative cognitive disorders in elderly patients undergoing major non-cardiac surgery: An open-label randomized controlled clinical trial

Characteristics associated with effectiveness in postoperative delirium research: a systematic review of randomised controlled trials with meta-regression and meta-analysis

BACKGROUND

Postoperative delirium remains prevalent despite extensive research through randomised trials aimed at reducing its incidence. Understanding trial characteristics associated with interventions' effectiveness facilitates data interpretation.

METHODS

Trial characteristics were extracted from eligible trials identified through two systematic literature searches. Multivariable meta-regression was used to investigate trial characteristics associated with effectiveness estimated using odds ratios. Meta-analysis was used to investigate pooled effectiveness.

RESULTS

We identified 201 eligible trials. Compared with China, trials from the USA/Canada (ratio of odds ratio, 1.89; 95% confidence interval, 1.45-2.45) and Europe/Australia/New Zealand (1.67; 1.29-2.18) had an 89% and 67% higher odds ratio, respectively, suggesting reduced effectiveness. The effectiveness was enhanced when the incidence of postoperative delirium increased (0.85; 0.79-0.92, per 10% increase). Trials with concerns related to deviations from intended interventions reported increased effectiveness compared with those at low risk (0.69; 0.53-0.90). Compared with usual care, certain interventions appeared to have reduced the incidence of postoperative delirium in low-risk trials with low-to-moderate certainty of evidence. However, these findings should be considered inconclusive because of challenges in grouping heterogeneous interventions, the limited number of eligible trials, the prevalence of small-scale studies, and potential publication bias.

CONCLUSIONS

The effectiveness of postoperative delirium trials varied based on the region of trial origin, the incidence of delirium, and the risk of bias. The limitations caution against drawing definitive conclusions from different bodies of evidence. These findings highlight the imperative need to improve the quality of research on a global scale.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO (CRD42023413984).

Exercise attenuates the perioperative neurocognitive disorder induced by hyperhomocysteinemia in mice

The perioperative neurocognitive disorder (PND) is a severe complication that affects millions of surgical patients each year. Homocysteine (Hcy) is known to increase the risk of developing PND in both young and elderly mice. However, whether Hcy alone can induce cognitive deficits in middle-aged mice (12-month-old), whether exercise can attenuate Hcy-induced hippocampus-related cognitive deficits after surgery through suppressing neuroinflammation, synaptic elimination, and the level of Hcy remains unknown. The present study aimed to answer these questions through testing the possibility of establishing a PND model using 12-month-old mice which received homocysteine injections before exploratory laparotomy and the therapeutic mechanism of exercise. In the present study, it was found that levels of serum homocysteine were age-dependently increased in mice with a significant difference between that of 18-month-old mice and 6-week, 6-month, and 12-month-old mice. PND occurred in 18-month but not in 12-month-old mice after exploratory laparotomy under isoflurane anesthesia. Intraperitoneal injection of Hcy for 3 consecutive days before surgery rendered 12-month-old mice to develop PND after abdominal laparotomy under isoflurane anesthesia at a minimal dosage of 20 mg/kg. Neuroinflammation and synaptic elimination was present in 12-month-old preoperative Hcy-injected mice. Preoperative voluntary wheel exercise could prevent PND in 12-month-old mice that have received Hcy injection before surgery, which might be related to the decreased level of serum Hcy. Activation of glial cells, proinflammatory phenotype markers and synaptic elimination were attenuated in the hippocampus of 12-month-old preoperative Hcy-injected mice by this exercise. These results provide direct evidence that hyperhomocysteinemia can induce postoperative cognitive deficits in middle-aged mice. Pre-surgery exercise can effectively prevent Hcy-precipitated postoperative cognitive dysfunction.

Update of the European Society of Anaesthesiology and Intensive Care Medicine evidence-based and consensus-based guideline on postoperative delirium in adult patients

Postoperative delirium (POD) remains a common, dangerous and resource-consuming adverse event but is often preventable. The whole peri-operative team can play a key role in its management. This update to the 2017 ESAIC Guideline on the prevention of POD is evidence-based and consensus-based and considers the literature between 01 April 2015, and 28 February 2022. The search terms of the broad literature search were identical to those used in the first version of the guideline published in 2017. POD was defined in accordance with the DSM-5 criteria. POD had to be measured with a validated POD screening tool, at least once per day for at least 3 days starting in the recovery room or postanaesthesia care unit on the day of surgery or, at latest, on postoperative day 1. Recent literature confirmed the pathogenic role of surgery-induced inflammation, and this concept reinforces the positive role of multicomponent strategies aimed to reduce the surgical stress response. Although some putative precipitating risk factors are not modifiable (length of surgery, surgical site), others (such as depth of anaesthesia, appropriate analgesia and haemodynamic stability) are under the control of the anaesthesiologists. Multicomponent preoperative, intra-operative and postoperative preventive measures showed potential to reduce the incidence and duration of POD, confirming the pivotal role of a comprehensive and team-based approach to improve patients' clinical and functional status.

Ultrasound-guided serratus anterior plane block to prevent neurocognitive impairment in elderly patients after thoracoscopic lobectomy: protocol for a single-centre, double-blind, randomised controlled trial

INTRODUCTION

Postoperative neurocognitive dysfunction (PND), including postoperative delirium (POD), is a common complication in elderly patients after major surgeries, often leading to poor postoperative recovery. Although the pathological mechanism underlying PND is still unclear, postoperative pain is strongly associated with the development of PND. The ultrasound-guided serratus anterior plane block (SAPB) has been reported to relieve postoperative pain in thoracic surgery. Therefore, this prospective trial hypothesises that SAPB may reduce the incidence of PND in the elderly undergoing thoracoscopic lobectomy.

METHODS AND ANALYSIS

This study is designed as a single-centre, double-blind, randomised controlled clinical trial. A total of 256 elderly patients scheduled to undergo thoracoscopic lobectomy at Shanghai Pulmonary Hospital will be randomly assigned to general anaesthesia group or SAPB group. The primary outcome is the incidence of PND 7 days postoperatively or before discharge from hospital. The secondary outcomes include the occurrence of POD, the postoperative pain scores, Quality of Recovery at 1-2 days postoperatively and incidence of PND at 3 months postoperatively. The levels of fasting blood glucose in peripheral blood will be examined before and 1-2 days postoperatively.

ETHICS AND DISSEMINATION

The trial has been approved by the Clinical Research Ethics Committee of Shanghai Pulmonary Hospital (identifier: K20-290). All participants will be required to provide written informed consent before any protocol-specific procedures. Findings will be disseminated in a peer-reviewed journal and in national and/or international meetings to guide future practice.

TRIAL REGISTRATION NUMBER

ChiCTR2100052633.

Lactate: A Theranostic Biomarker for Metabolic Psychiatry?

Alterations in neurometabolism and mitochondria are implicated in the pathophysiology of psychiatric conditions such as mood disorders and schizophrenia. Thus, developing objective biomarkers related to brain mitochondrial function is crucial for the development of interventions, such as central nervous system penetrating agents that target brain health. Lactate, a major circulatory fuel source that can be produced and utilized by the brain and body, is presented as a theranostic biomarker for neurometabolic dysfunction in psychiatric conditions. This concept is based on three key properties of lactate that make it an intriguing metabolic intermediate with implications for this field: Firstly, the lactate response to various stimuli, including physiological or psychological stress, represents a quantifiable and dynamic marker that reflects metabolic and mitochondrial health. Second, lactate concentration in the brain is tightly regulated according to the sleep-wake cycle, the dysregulation of which is implicated in both metabolic and mood disorders. Third, lactate universally integrates arousal behaviours, pH, cellular metabolism, redox states, oxidative stress, and inflammation, and can signal and encode this information via intra- and extracellular pathways in the brain. In this review, we expand on the above properties of lactate and discuss the methodological developments and rationale for the use of functional magnetic resonance spectroscopy for in vivo monitoring of brain lactate. We conclude that accurate and dynamic assessment of brain lactate responses might contribute to the development of novel and personalized therapies that improve mitochondrial health in psychiatric disorders and other conditions associated with neurometabolic dysfunction.

Postoperative serum CHI3L1 level is associated with postoperative cognitive dysfunction in elderly patients after hip fracture surgery: A prospective observational study

Objectives

Postoperative cognitive dysfunction (POCD) is a common postoperative complication in older patients. Chitinase-3-like-1 protein (CHI3L1) is identified as a neuroinflammatory biomarker and impairs cognitive function. This study aimed to evaluate the association between serum levels of CHI3L1 and POCD and explore the levels of interleukin-6 (IL-6), IL-1β and C-reactive protein (CRP) in the elderly after total hip arthroplasty (THA).

Patients and methods

A total of 76 elderly patients undergoing THA were enrolled in the prospective observational study. Serum CHI3L1 levels were measured 1 day before and 1 day after surgery and other perioperative factors were also noted. The correlations between mediators of inflammation in the two groups were compared via Spearman correlation coefficients. The receiver operating characteristic (ROC) curves were implemented to analyze the predictive values of serum CHI3L1 and other inflammatory factors for POCD. And factors associated with POCD were analyzed by univariate and multivariate logistics.

Results

POCD was observed in 31.6% of patients 1 week after surgery. Postoperative serum CHI3L1 levels were higher in POCD patients than in non-POCD patients [1348.26(778.46-1889.77) VS 2322.86(1686.88-2517.35) ng/ml, P < 0.001]. Postoperative serum CHI3L1 level was positively correlated with postoperative IL-6 level (r = 0.284, P = 0.013). Compared with IL-6, IL-1β, and CRP, postoperative CHI3L1 level has the highest predictive value for POCD with the area under the curve (AUC) value of 0.779 according to the ROC curve. By the multivariate logistic regression analysis, elevated postoperative serum CHI3L1 level was found to be an independent risk factor for POCD 1 week after surgery (odds ratio = 1.204, 95% confidence interval = 1.087-1.332, P = 0.001).

Conclusion

Postoperative elevated serum CHI3L1 level was significantly associated with the incident of POCD, and positively correlated with postoperative IL-6 level in the elderly after THA. This biomarker may have potential utility for further elucidating the etiology of POCD.

Effects of single-use alfentanil versus propofol on cognitive functions after colonoscopy: A randomized controlled trial

Purpose

Colonoscopy is often accompanied by short-term postoperative cognitive decline. We aimed to explore whether single-use alfentanil for patients undergoing elective colonoscopy could reduce cognitive impairment at discharge compared with propofol.

Patients and methods

172 adult patients undergoing elective colonoscopy were randomized to receive intravenous propofol at 2 mg/kg (group P) or alfentanil at 10 μg/kg (group A); 40 healthy volunteers were included in the blank group. Cognitive function was considered the primary outcome and was measured using five neuropsychological tests before sedation and discharge. The z-score method was used to determine cognitive dysfunction according to z-score >1.96 in two types of neuropsychological tests. Other outcomes included discharge time, vital signs, associated adverse events during colonoscopy, and the satisfaction level of patients and endoscopic physicians.

Results

164 patients (78 in group A and 86 in group P) completed the study protocol. At discharge, the incidence of cognitive dysfunction in group P was 23% and was significantly lower in the alfentanil group (2.5%), with a relative risk of 0.11 (95% confidence interval: 0.03-0.46, P < 0.001). The incidence of hypotension in group A was lower than that in group P (3.8% vs 22.1%, relative risk = 0.17 [95% confidence interval: 0.05-0.46, P = 0.001]), and the discharge time in group A was shorter than that in group P (5 [(Rutter and et al., 2016; Zhang and et al., 2013; Hirsh and et al., 2006; Zhou and et al., 2021; Singh and et al., 2008; Ko and et al., 2010; Sargin et al., 2019) 3-93-9 vs 13 [(Ekmekci and et al., 2017; Eberl and et al., 2012; Eberl and et al., 2014; N'Kaoua and et al., 2002; Chung et al., 1995; Berger and et al., 2019; Quan and et al., 2019; Deng and et al., 2021; Gualtieri and Johnson, 2006) 10-1810-18 min, P < 0.001).

Conclusion

For patients undergoing colonoscopy, single-use alfentanil causes less damage to postoperative cognitive function, less risk of hypotension, and shorter discharge time than propofol.

Preoperative Risk Factors Associated with Increased Incidence of Postoperative Delirium: Systematic Review of Qualified Clinical Studies

Postoperative delirium (POD) is an acute alteration of mental state, characterized by reduced awareness and attention, occurring up to five postoperative days after recovery from anesthesia. Several original studies and reviews have identified possible perioperative POD risk factors; however, there is no comprehensive review of the preoperative risk factors in patients diagnosed with POD using only validated diagnostic scales. The aim of this systematic review was to report the preoperative risk factors associated with an increased incidence of POD in patients undergoing non-cardiac and non-brain surgery. The reviewed studies included original research papers that used at least one validated diagnostic scale to identify POD occurrence for more than 24 h. A total of 6475 references were retrieved from the database search, with only 260 of them being suitable for further review. Out of the 260 reviewed studies, only 165 that used a validated POD scale reported one or more preoperative risk factors. Forty-one risk factors were identified, with various levels of statistical significance. The extracted risk factors could serve as a preoperative POD risk assessment workup. Future studies dedicated to the further evaluation of the specific preoperative risk factors' contributions to POD could help with the development of a weighted screening tool.

Perioperative probiotics attenuates postoperative cognitive dysfunction in elderly patients undergoing hip or knee arthroplasty: A randomized, double-blind, and placebo-controlled trial

Background

Postoperative cognitive dysfunction (POCD) is a common complication in elderly patients following surgery. The preventive and/or treatment strategies for the incidence remain limited.

Objective

This study aimed to investigate the preventive effect of perioperative probiotic treatment on POCD in elderly patients undergoing hip or knee arthroplasty.

Methods

After obtaining ethical approval and written informed consent, 106 patients (age ≥60 years) were recruited, who scheduled elective hip or knee arthroplasty, from 16 March 2021 to 25 February 2022 for this randomized, double-blind, and placebo-controlled trial. They were randomly assigned with a 1:1 ratio to receive either probiotics or placebo treatment (four capsules, twice/day) from hospital admission until discharge. Cognitive function was assessed with a battery of 11 neuropsychological tests on the admission day and the seventh day after surgery, respectively.

Results

A total of 96 of 106 patients completed the study, and their data were finally analyzed. POCD occurred in 12 (26.7%) of 45 patients in the probiotic group and 29 (56.9%) of 51 patients in the placebo group (relative risk [RR], 0.47 [95% confidence interval [CI], 0.27 to 0.81]; P = 0.003). Among them, mild POCD occurred in 11 (24.4%) in the probiotic group and 24 (47.1%) in the placebo group (RR, 0.52 [95% CI, 0.29 to 0.94]; P = 0.022). No significant difference in severe POCD incidence was found between the two groups (P = 0.209). Compared with the placebo group, the verbal memory domain cognitive function was mainly improved in the probiotic group.

Conclusion

Probiotics may be used perioperatively to prevent POCD development and improve verbal memory performance in elderly patients receiving hip or knee arthroplasty.

Clinical trial registration

www.chictr.org.cn, identifier: ChiCTR2100045620.

Fluoxetine for reducing postoperative cognitive dysfunction in elderly patients after total knee replacement: study protocol for a single-centre, double-blind, randomised, parallel-group, superiority, placebo-controlled trial

INTRODUCTION

Postoperative cognitive dysfunction (POCD) is a common complication following major surgical procedures. The underlying pathophysiology is poorly understood, but the role of neuroinflammation is strongly implicated. Given the antineuroinflammatory and neuroprotective effects of fluoxetine, we hypothesise that fluoxetine may reduce the cumulative incidence of POCD in elderly patients undergoing total knee arthroplasty (TKA).

METHODS AND ANALYSIS

This is a prospective, randomised, double-blind, parallel-group, placebo-controlled, superiority trial. Five hundred elderly patients undergoing unilateral TKA will be randomly assigned to the fluoxetine and placebo groups. The fluoxetine group will receive fluoxetine 20 mg daily 8 weeks preoperatively, and the placebo group will receive placebo capsules daily 8 weeks preoperatively. The primary outcome is the cumulative incidence of POCD at 1 month postoperatively. The secondary outcomes include the occurrence of delirium, the area under the curve of the Numeric Rating Scale pain scores over time, and sleep disturbance. Data on all the results, risk factors and adverse events will also be collected and analysed.

ETHICS AND DISSEMINATION

The Fujian Provincial Hospital Ethics Board has approved the protocol for this trial (identifier number: K2021-01-009). All participants will be required to provide written informed consent before any protocol-specific procedures.

TRIAL REGISTRATION NUMBER

ChiCTR2100050424.

The Association Between Systemic Immune-Inflammation Index and Postoperative Cognitive Decline in Elderly Patients

Purpose

Postoperative cognitive decline (POCD) is highly prevalent in elderly patients who received surgery. The systemic immune-inflammation index (SII) has been shown to be an independent predictor of many diseases associated with inflammation, but the relationship between the SII and POCD is unknown. We aimed to investigate the association between POCD and SII levels to examine the potential of SII in predicting POCD in elderly patients.

Patients and Methods

The present study was carried out among elderly patients who underwent elective orthopedics operation in our hospital, and SII, neutrophil to lymphocyte ratio (NLR), monocyte to lymphocyte ratio (MLR) were calculated from the admission blood sample. POCD was measured by Mini-mental State Examination (MMSE) in elderly patients. The association between SII levels and POCD was analyzed by binary logistic regression analysis.

Results

Finally, 19 (25%) of 76 patients were diagnosed with POCD. Compared with Non-POCD patients, POCD patients showed significantly higher levels of NLR, MLR, SII, especially SII at admission. SII was independently associated with the occurrence of POCD through the logistic regression analysis. Receiver operating characteristic curve analysis indicated that preoperative SII was a significant predictor for POCD, and the area under the curve was 0.909.

Conclusion

Our data suggest that preoperative NLR, MLR, SII levels in the blood are related to the occurrence of POCD. Preoperative SII level is a prognostic biomarker of POCD in elderly patients after orthopedics operation. More clinical studies are needed to further verify the value of SII in POCD.

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

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

Ultrasound-Guided Continuous Thoracic Paravertebral Infusion of Methylene Blue in the Treatment of Postherpetic Neuralgia: A Prospective, Randomized, Controlled Study

Introduction

Postherpetic neuralgia (PHN) is the most common complication of herpes zoster. Methylene blue (MB) is an inhibitor of nitric oxide synthesis with potentially analgesic and anti-inflammatory properties. Studies have demonstrated that thoracic paravertebral single MB injection is effective in treating chronic pain. However, there are rare reports of the efficacy of continuous thoracic paravertebral infusion of MB for pain management in PHN patients. The purpose of this study was to evaluate the therapeutic effects of continuous thoracic paravertebral infusion of MB on PHN.

Methods

A total of 104 PHN patients were randomly divided into two groups: the control group (continuous thoracic paravertebral infusion of 5% lidocaine in a total volume of 300 ml) and the MB group (continuous thoracic paravertebral infusion of 5% lidocaine plus 0.2% MB in a total volume of 300 ml). All patients were evaluated using the Numerical Rating Scale (NRS), Insomnia Severity Index (ISI), Patient Health Questionnaire-9 (PHQ-9), 36-Item Short-Form Health Survey (SF-36), and medication doses before and after the procedure. The effective treatment rate and adverse complications were recorded 6 months after the procedure.

Results

In both groups, the NRS scores, ISI scores, PHQ-9 scores, and rescue medication dosages were significantly decreased at different time points after treatment compared to baseline, while the SF-36 scores were evidently improved at different time points after treatment compared to baseline. Compared with the control group, the MB group had significantly reduced NRS scores, ISI scores, PHQ-9 scores, and rescue medication dosages at each observation time point. Furthermore, the SF-36 scores in the MB group were significantly higher than those in the control group at each observation time point. The total effective treatment rate of the MB group was higher than that of the control group 6 months after the procedure. No severe adverse complications were observed in either group.

Conclusions

Ultrasound-guided continuous thoracic paravertebral infusion with MB is a safe and effective therapy for PHN. Continuous infusion with MB can significantly reduce pain intensity, improve pain-related depression, increase quality of life, and decrease the amount of rescue medicine with no serious adverse complications.