Postoperative serum thioredoxin concentrations correlate with delirium and cognitive dysfunction after hip fracture surgery in elderly patients

Comparative evaluation of isoflurane and desflurane for postoperative cognitive decline in elderly patients: A prospective observational pilot study

BACKGROUND

Approximately 16%-62% of patients undergoing non cardiac surgeries develop postoperative cognitive dysfunction. We compared the incidence of postoperative cognitive dysfunction in older adults aged 60-80 years who underwent open abdominal surgeries under general anaesthesia using isoflurane or desflurane and correlated it with the serum concentration of interleukin 1, interleukin 6, tumour necrosis factor alpha, amyloid β and S100 on postoperative day 3.

METHOD

Forty American Association of Anesthesiologists Physical Classification I or II patients were included after acquiring institutional ethics committee approval, registering in the Clinical Trials Registry - India, and informed written consent. They underwent open abdominal surgery under general anaesthesia and epidurals between 2017 and 2019. Patients with substance abuse or any disorder affecting cognition were excluded. Postoperative cognitive dysfunction was assessed by Stroop test, Wisconsin Card Sorting Test, Trail making test - B, Porteus Maze test, PGI memory scale, mini-mental state examination, and Bender Gestalt test the day before surgery and on the third postoperative day along with blood samples.

RESULTS

Thirty-seven percent of the patients developed postoperative cognitive dysfunction. The risk was similar to isoflurane in comparison with desflurane (risk ratio: 0.65, 95% confidence interval: 0.30, 1.40). A significant percentage increase in reaction time for Porteus Maze test and Trail making test - B was noted with isoflurane (6.69 (4.20-8.94) and 8.01 (2.08-12.5), respectively) in comparison with desflurane group (13.01 (9.09-17.33), p = 0.003 and 11.62 (7.5-17.5), p = 0.017, respectively).

CONCLUSION

Isoflurane and desflurane had a similar impact on the elderly for developing postoperative cognitive dysfunction and no correlation with any of the biomarkers used in the study on postoperative day 3.

Research progress on the association between MicroRNA and postoperative cognitive dysfunction

Postoperative cognitive dysfunction (POCD) is a significant complication following surgery. The precise mechanisms underlying POCD remain elusive, although it is speculated that they involve central nervous system inflammation, oxidative stress and cellular apoptosis. MicroRNAs (miRNAs), a class of non-coding RNAs widely distributed in eukaryotes, have been implicated in the pathogenesis of neurodegenerative disorders and could potentially impact POCD. This review explores the association between miRNAs and POCD and provides an overview of the progress of current research on miRNAs in the pathogenesis, diagnosis, and treatment of POCD.

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.

Identification of individuals at risk for postoperative cognitive dysfunction (POCD)

Postoperative cognitive dysfunction (POCD) is common, occurring in around 10-54% of individuals within first few weeks after surgery. Although the majority of POCD is less commonly persistent later than 3 months following surgery, the condition increases length of stay (LOS), mortality and long-term cognitive decline, raising the need for a broad screening to identify individuals at risk for POCD during the perioperative period. In this narrative review, we summarize preoperative, intraoperative and postoperative risk factors for POCD reported in last 5 years and discuss neuropsychological tools and potential biomarkers and time points for assessment that might be suitable for clinical use. We aim to provide crucial information for developing a strategy of routine screening for POCD, which may assist with better identification of at-risk individuals for early interventions. Very importantly, the utilization of a standardized strategy may also allow higher consistency and comparability across different studies.

The impact of glutathione metabolism in autism spectrum disorder

This paper reviews the potential role of glutathione (GSH) in autism spectrum disorder (ASD). GSH plays a key role in the detoxification of xenobiotics and maintenance of balance in intracellular redox pathways. Recent data showed that imbalances in the GSH redox system are an important factor in the pathophysiology of ASD. Furthermore, ASD is accompanied by decreased concentrations of reduced GSH in part caused by oxidation of GSH into glutathione disulfide (GSSG). GSSG can react with protein sulfhydryl (SH) groups, thereby causing proteotoxic stress and other abnormalities in SH-containing enzymes in the brain and blood. Moreover, alterations in the GSH metabolism via its effects on redox-independent mechanisms are other processes associated with the pathophysiology of ASD. GSH-related regulation of glutamate receptors such as the N-methyl-D-aspartate receptor can contribute to glutamate excitotoxicity. Synergistic and antagonistic interactions between glutamate and GSH can result in neuronal dysfunction. These interactions can involve transcription factors of the immune pathway, such as activator protein 1 and nuclear factor (NF)-κB, thereby interacting with neuroinflammatory mechanisms, ultimately leading to neuronal damage. Neuronal apoptosis and mitochondrial dysfunction are recently outlined as significant factors linking GSH impairments with the pathophysiology of ASD. Moreover, GSH regulates the methylation of DNA and modulates epigenetics. Existing data support a protective role of the GSH system in ASD development. Future research should focus on the effects of GSH redox signaling in ASD and should explore new therapeutic approaches by targeting the GSH system.

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

STUDY OBJECTIVE

The purpose of the present study was to investigate whether methylene blue (MB) could reduce the incidences of postoperative delirium (POD) and early postoperative cognitive dysfunction (POCD) in elderly patients undergoing major non-cardiac surgery.

DESIGN

Prospective, randomized, open-label clinical trial.

SETTING

University-affiliated hospital.

PATIENTS

Two hundred and forty-eight elderly patients scheduled for non-cardiac surgery.

INTERVENTIONS

Elderly patients undergoing non-cardiac major surgery were randomly assigned to MB group (n = 124), who receiving intravenous infusion of 2 mg/kg MB within 60 min immediately after anesthetic induction, or control group (n = 124), who receiving equal volume saline in the same way.

MEASUREMENTS

All patients were evaluated with delirium and neuropsychological batteries before and after surgery, as well as perioperative adverse events. Two plasma biomarkers superoxide dismutase (SOD) and homocysteine (HCY) were measured pre- and post-operatively.

MAIN RESULTS

There were total 39 cases(15.7%)experienced POD. The incidence of POD in MB group was significantly less than that in control group (7.3% vs. 24.2%, OR = 0.24, 95%CI: 0.11-0.53, p < 0.001). The incidence of early POCD at postoperative 7th day in MB group was also less than that in control group (16.1% vs. 40.2%, OR = 0.30, 95% CI: 0.16-0.57, p < 0.001). The adverse events were comparable in both groups. In addition, there was no significant correlation between POD/POCD and levels of SOD or HCY.

CONCLUSION

We conclude that intraoperative intravenous 2 mg/kg MB could significantly reduce the incidences of POD and early POCD in elderly surgical patients, while not remarkably increase incidence of perioperative adverse events, suggesting MB may be clinically effective and safe for prevention of early postoperative neurocognitive disorders.

Incidence and risk factors for acute delirium in older patients with a hip fracture: A retrospective cohort study

This retrospective cohort study aimed to determine the incidence, and preoperative, intraoperative, and postoperative risk factors for postoperative delirium in older patients undergoing surgical fixation of a hip fracture. Electronic medical records were examined of 260 patients who underwent a surgical fixation of a hip fracture between June 2017 and October 2018 at a university-affiliated tertiary care hospital in Victoria, Australia. Demographic, clinical, and perioperative data were examined for potential risk factors for postoperative delirium. Of the 260 patients, 63 patients (24.2%) developed delirium postoperatively. Univariate logistic regression analysis indicated that advanced age, comorbidity, cognitive impairment, dementia, American Society of Anesthesiologists score, and antipsychotic usage were significant risk factors for delirium, while doses of paracetamol, fentanyl, and diazepam showed complex associations. Multivariate logistic regression analysis determined comorbidity and cognitive impairment as independent risk factors for the development of delirium. This study demonstrates the importance of evaluation of medications prescribed in the perioperative period as modifiable risk factors, in order to identify patients at high risk of delirium and enable targeted monitoring and treatment during patients' hospitalization.

Preoperative prognostic nutritional index predicts postoperative delirium in elderly patients after hip fracture surgery

BACKGROUND

Postoperative delirium (POD) is a very common complication in elderly patients after hip fracture surgery, which has poorly understood pathophysiology. This study aimed to investigate potential risk factors for POD.

METHODS

Elderly patients (aged ≥65 years) scheduled to undergo selective surgery in our hospital were consecutively recruited. Patient characteristics, preoperative laboratory tests and prognostic nutritional index (PNI) levels were compared between patients with or without POD. The risk factors for POD were evaluated by univariate and multivariate logistic regression analyses. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the predictive value of PNI and age for POD.

RESULTS

Fifty-seven of the 163 enrolled patient had suffered POD within postoperative day 7 with an incidence of 35.0%. Multivariate logistic analyses revealed that an advanced age (cut-off value: 71.5 years, sensitivity: 48.1%, specificity: 75.4%, odds ratio (OR): 3.24, 95% CI: 1.16-8.69, P = 0.026) and lower PNI level (cut-off value: 47.45, sensitivity: 86.0%, specificity: 51.9%, OR: 2.88, 95% CI: 1.25-6.64, P = 0.012) were two independent predictive factors associated with POD. According to the ROC curve analysis, preoperative PNI level was a predictor for POD with an area under the curve of 0.686 (95% CI: 0.604-0.767, P < 0.001).

CONCLUSIONS

Advanced age and lower preoperative PNI level were significantly associated with POD in elderly patients after hip fracture surgery.

Postoperative cognitive dysfunction in elderly patients undergoing hip arthroplasty

Even after successful hip arthroplasty, elderly patients who have undergone this procedure remain subject to cognitive decline and may collectively develop postoperative cognitive dysfunction (POCD). However, no consensus exists as to the risk factors resulting in a higher likelihood that a patient may present with this complication, and the aetiology of POCD is not well understood. We conducted a systematic review of papers concerning the influence of POCD-related risk factors in patients undergoing hip arthroplasty but limited the literature search to papers in English. A systematic and electronic search for manuscripts in the PubMed database was performed in order to identify all studies in which the risk factors for POCD were investigated. Articles were also obtained from the authors' files. Keywords for the search were postoperative cognitive dysfunction/change/impairment/decline/deficit, elderly/older/aged patients, and hip arthroplasty/replacement surgery. The evidence published to date suggests that POCD is a multifactorial disease, which includes an individual patient's characteristics, surgery, type of anaesthesia, and pain levels. All of these factors can increase the risk of POCD incidence. There are a number of factors that appear to influence the risk of early cognitive dysfunction after hip arthroplasty. Nevertheless, the specific mechanism and explicit risk factors associated with this cognitive dysfunction are not completely understood. Hip arthroplasty has made it possible for older patients to find relief from pain and improve their function, whereas it also increases the risk for suffering POCD that may affect these patients' quality of life and increase their mortality. Therefore, it is worthwhile investigating the mechanism of POCD in future studies in order to prevent and treat this condition.

Serum biomarkers of delirium in the elderly: a narrative review

Delirium after surgery and in the intensive care unit (ICU) remains a challenge for patients, families, and caregivers. Over the years, many promising biomarkers have been investigated as potential instruments for risk stratification of delirium. This review aimed to identify and assess the clinical usefulness of candidate serum biomarkers associated with hospital delirium in patients aged 60 years and older. We performed a time-unlimited review of publications indexed in PubMed, Cochrane, Embase, and MEDLINE databases until June 2019 that evaluated baseline and/or longitudinal biomarker measurements in patients suffering from delirium at some point during their hospital stay. A total of 32 studies were included in this review reporting information on 7610 patients. Of these 32 studies, twenty-four studies reported data from surgical patients including four studies in ICU cohorts, five studies reported data from medical patients (1026 patients), and three studies reported data from a mixed cohort (1086 patients), including one study in an ICU cohort. Findings confirm restricted clinical usefulness to predict or diagnose delirium due to limited evidence on which biomarkers can be used and limited availability due to non-routine use.

Protocol for a prospective cohort study of assessing postoperative cognitive changes after total hip and knee arthroplasty in the Greater Toronto area

INTRODUCTION

Cognitive changes after anaesthesia and surgery, such as delirium and postoperative cognitive dysfunction (POCD), are common and lead to poor outcomes and increased healthcare costs. While several interventions for delirium exist, there are no effective treatment strategies for POCD. Understanding the risks and contributing factors may offer clinicians unique opportunities to better identify and develop preventative interventions for those at higher risk. Elderly patients undergoing orthopaedic surgery are at high risk of developing postoperative delirium (PD) and POCD. The incidence of POCD has not been rigorously studied in the total hip and knee arthroplasty (THA/TKA) population. Therefore, we have designed a prospective, observational cohort study to assess POCD in patients undergoing THA/TKA, both increasingly common procedures. The incidence of PD and POCD in a high volume, tertiary care arthroplasty centre will be determined and associated risk factors will be identified.

METHODS AND ANALYSIS

Cognitive function will be tested with a computer-based cognitive assessment tool [CogState Brief Battery], preoperatively at baseline and postoperatively while in hospital at (<3 days), 6 weeks and 4.5 months. The primary outcome is the incidence of postoperative cognitive decline at 4.5 months. Logistic regression analysis is planned to test the association of POCD with several potential risk factors. In addition, delirium will be assessed preoperatively and postoperatively in the hospital using the Confusion Assessment Method (3D-CAM).

ETHICS AND DISSEMINATION

The protocol for this prospective observational study was approved by the Sunnybrook Health Sciences Centre Research Ethics Board (REB#: 040-2017). Recruitment commenced in May 2017 and will continue until 2019. The results will be disseminated in a peer-reviewed journal and in scientific meetings.

TRIAL REGISTRATION NUMBER

NCT03147937.