Post-operative delirium associated with metabolic alterations following hemi-arthroplasty in older patients

Decreased DTI-ALPS index in delirium: a preliminary MRI study

PURPOSE

Delirium is linked to brain abnormalities, yet the role of the glymphatic system is not well understood. This study aims to examine alterations in brain physiology in delirium by using diffusion-tensor imaging (DTI) to assess water diffusion along the perivascular space (ALPS) and to explore its correlation with clinical symptoms.

METHODS

We examined 15 patients with delirium and 15 healthy controls, measuring water diffusion metrics along the x-, y-, and z-axes in both projection and association fibers to determine the DTI-ALPS index. We used a general linear model, adjusted for age and sex, to compare the DTI-ALPS index between groups. We also investigated the relationship between the DTI-ALPS index and clinical symptoms using partial correlations.

RESULTS

Patients with delirium exhibited significantly lower DTI-ALPS indices compared to healthy controls (1.25 ± 0.15 vs. 1.38 ± 0.10, t = 2.903, p = 0.007; 1.27 ± 0.16 vs. 1.39 ± 0.08, 1.22 ± 0.16 vs. 1.37 ± 0.14, t = 2.617, p = 0.014; t = 2.719, p = 0.011; respectively). However, there was no significant correlation between the DTI-ALPS index and clinical symptoms.

CONCLUSION

Our findings indicate a decreased DTI-ALPS index in patients with delirium, suggesting potential alterations in brain physiology that may contribute to the pathophysiology of delirium. This study provides new insights into the mechanisms underlying delirium.

The interrelationship between multiple long-term conditions (MLTC) and delirium: a scoping review

INTRODUCTION

Delirium and multiple long-term conditions (MLTC) share numerous risk factors and have been shown individually to be associated with adverse outcomes following hospitalisation. However, the extent to which these common ageing syndromes have been studied together is unknown. This scoping review aims to summarise our knowledge to date on the interrelationship between MLTC and delirium.

METHODS

Searches including terms for delirium and MLTC in adult human participants were performed in PubMed, EMBASE, Medline, Psycinfo and CINAHL. Descriptive analysis was used to summarise findings, structured according to Synthesis Without Meta-analysis reporting guidelines.

RESULTS

After removing duplicates, 5256 abstracts were screened for eligibility, with 313 full-texts sought along with 17 additional full-texts from references in review articles. In total, 140 met inclusion criteria and were included in the final review. Much of the literature explored MLTC as a risk factor for delirium (n = 125). Fewer studies explored the impact of MLTC on delirium presentation (n = 5), duration (n = 3) or outcomes (n = 6) and no studies explored how MLTC impacts the treatment of delirium or whether having delirium increases risk of developing MLTC. The most frequently used measures of MLTC and delirium were the Charlson Comorbidity Index (n = 98/140) and Confusion Assessment Method (n = 81/140), respectively.

CONCLUSION

Existing literature largely evaluates MLTC as a risk factor for delirium. Major knowledge gaps identified include the impact of MLTC on delirium treatment and the effect of delirium on MLTC trajectories. Current research in this field is limited by significant heterogeneity in defining both MLTC and delirium.

Discovery of Delirium Biomarkers through Minimally Invasive Serum Molecular Fingerprinting

Delirium presents a significant clinical challenge, primarily due to its profound impact on patient outcomes and the limitations of the current diagnostic methods, which are largely subjective. During the COVID-19 pandemic, this challenge was intensified as the frequency of delirium assessments decreased in Intensive Care Units (ICUs), even as the prevalence of delirium among critically ill patients increased. The present study evaluated how the serum molecular fingerprint, as acquired by Fourier-Transform InfraRed (FTIR) spectroscopy, can enable the development of predictive models for delirium. A preliminary univariate analysis of serum FTIR spectra indicated significantly different bands between 26 ICU patients with delirium and 26 patients without, all of whom were admitted with COVID-19. However, these bands resulted in a poorly performing Naïve-Bayes predictive model. Considering the use of a Fast-Correlation-Based Filter for feature selection, it was possible to define a new set of spectral bands with a wider coverage of molecular functional groups. These bands ensured an excellent Naïve-Bayes predictive model, with an AUC, a sensitivity, and a specificity all exceeding 0.92. These spectral bands, acquired through a minimally invasive analysis and obtained rapidly, economically, and in a high-throughput mode, therefore offer significant potential for managing delirium in critically ill patients.

Lower alpha frequency of intraoperative frontal EEG is associated with postoperative delirium: A secondary propensity-matched analysis

BACKGROUND

Postoperative delirium (POD) is a serious complication of surgery, especially in the elderly patient population. It has been proposed that decreasing the amount of anesthetics by titrating to an EEG index will lower POD rate, but clear evidence is missing. A strong age-dependent negative correlation has been reported between the peak oscillatory frequency of alpha waves and end-tidal anesthetic concentration, with older patients generating slower alpha frequencies. We hypothesized, that slower alpha oscillations are associated with a higher rate of POD.

METHOD

Retrospective analysis of patients` data from a prospective observational study in cardiac surgical patients approved by the Bernese Ethics committee. Frontal EEG was recorded during Isoflurane effect-site concentrations of 0.7 to 0.8 and peak alpha frequency was measured at highest power between 6 and 17 Hz. Delirium was assessed by chart review. Demographic and clinical characteristics were compared between POD and non-POD groups. Selection bias was addressed using nearest neighbor propensity score matching (PSM) for best balance. This incorporated 18 variables, whereas patients with missing variable information or without an alpha oscillation were excluded.

RESULT

Of the 1072 patients in the original study, 828 were included, 73 with POD, 755 without. PSM allowed 328 patients into the final analysis, 67 with, 261 without POD. Before PSM, 8 variables were significantly different between POD and non-POD groups, none thereafter. Mean peak alpha frequency was significantly lower in the POD in contrast to non-POD group before and after matching (7.9 vs 8.9 Hz, 7.9 vs 8.8 Hz respectively, SD 1.3, p < 0.001).

CONCLUSION

Intraoperative slower frontal peak alpha frequency is independently associated with POD after cardiac surgery and may be a simple intraoperative neurophysiological marker of a vulnerable brain for POD. Further studies are needed to investigate if there is a causal link between alpha frequency and POD.

Dexmedetomidine adjunct to ropivacaine for ultrasound-guided transversus abdominis plane block for open inguinal hernia repair in the older adults: A randomised clinical trial

OBJECTIVE

The aim of this study was to evaluate the effect of adding dexmedetomidine to ropivacaine on pain relief and quality of recovery in older patients undergoing open inguinal hernia repair surgeries.

METHODS

This was a prospective and randomised clinical trial of 102 patients aged over 65 years who received an ultrasound-guided transversus open mesh herniorrhaphy abdominis plane (TAP) block with either 0.375% ropivacaine 20 ml (Group R, n = 47) or 0.375% ropivacaine combined with 1 μg/kg dexmedetomidine 20 ml (Group RD, n = 45) in the pre-anaesthesia care unit before elective open inguinal hernia surgeries. The primary outcome measure was Visual Analogue Scale (VAS) pain scores at rest and on movement at 2, 4, 8, 12 and 24 h and at 1 and 3 months' postoperatively. The secondary outcome measures were the incidence of post-operative delirium (POD), nausea and vomiting and the occurrence of side effects or complications on post-operative day 1.

RESULTS

Group RD had lower VAS scores at rest and on movement at 8 and 12 h postoperatively and a lower incidence of POD on the post-operative day 1 than Group R. Transient bradycardia was more frequent in Group RD than in Group R, and side effects or post-operative complications were reported in either group.

CONCLUSION

The addition of dexmedetomidine to ropivacaine in a TAP block enhances postoperative analgesia during hospitalisation and improves the quality of recovery without affecting chronic pain in older patients undergoing open inguinal hernia repair surgery.

Predictive value of the geriatric nutrition risk index for postoperative delirium in elderly patients undergoing cardiac surgery

AIMS

The aims of the study were to determine the relationship between preoperative geriatric nutritional risk index (GNRI) and the occurrence of postoperative delirium (POD) in elderly patients after cardiac surgery and to evaluate the additive value of GNRI for predicting POD.

METHODS

The data were extracted from the Multiparameter Intelligent Monitoring in Intensive Care (MIMIC-IV) database. Patients who underwent cardiac surgery and were aged 65 or older were included. The relationship between preoperative GNRI and POD was investigated using logistic regression. We determined the added predictive value of preoperative GNRI for POD by measuring the changes in the area under the receiver operating characteristic curve (AUC) and calculating the net reclassification improvement (NRI) and integrated discrimination improvement (IDI).

RESULTS

A total of 4286 patients were included in the study, and 659 (16.1%) developed POD. Patients with POD had significantly lower GNRI scores than patients without POD (median 111.1 vs. 113.4, p < 0.001). Malnourished patients (GNRI ≤ 98) had a significantly higher risk of POD (odds ratio, 1.83, 90% CI, 1.42-2.34, p < 0.001) than those without malnutrition (GNRI > 98). This correlation remains after adjusting for confounding variables. The addition of GNRI to the multivariable models slightly but not significantly increases the AUCs (all p > 0.05). Incorporating GNRI increases NRIs in some models and IDIs in all models (all p < 0.05).

CONCLUSIONS

Our results showed a negative association between preoperative GNRI and POD in elderly patients undergoing cardiac surgery. The addition of GNRI to POD prediction models may improve their predictive accuracy. However, these findings were based on a single-center cohort and will need to be validated in future studies involving multiple centers.

Fish oil omega-3 Fatty Acids Alleviate Postoperative delirium-like Behavior in aged mice by Attenuating Neuroinflammation and Oxidative Stress

Postoperative delirium (POD) is a common and serious neuropsychiatric syndrome among older patients, and lacks effective therapies. Omega-3 fatty acids, possessing anti-inflammatory and antioxidant properties, have shown potent neuroprotective effects in several diseases. The present study investigated whether omega-3 fatty acids could exert a neuroprotective role against POD in aged mice. A mouse model of POD was established to explore the role of omega-3 fatty acids in laparotomy-induced delirium-like behavior by evaluating systemic inflammatory changes, neuroinflammation, oxidative stress, and behavior at different time points in aged mice. Oral gavage with omega-3 fatty acids (300 mg/kg) for 3 weeks before surgery significantly attenuated anesthesia/surgery-induced POD-like behavior and the accumulation of proinflammatory cytokines from the peripheral blood in aged mice. Moreover, it also remarkably mitigated neuroinflammation and the oxidative stress response (malondialdehyde [MDA] and superoxide dismutase [SOD]) in the prefrontal cortex and hippocampus of surgical mice. Our findings provided evidence that pretreatment with omega-3 fatty acids may play a vital role in the treatment of POD through mechanisms involving its anti-inflammatory and antioxidant effects, which may be a promising prevention strategy for POD in aged patients.

Gene networks for use in metabolomic data analysis of blood plasma from patients with postoperative delirium

Postoperative delirium (POD) is considered one of the most severe complications, resulting in impaired cognitive function, extended hospitalization, and higher treatment costs. The challenge of early POD diagnosis becomes particularly significant in cardiac surgery cases, as the incidence of this complication exceeds 50 % in certain patient categories. While it is known that neuroinflammation, neurotransmitter imbalances, disruptions in neuroendocrine regulation, and interneuronal connections contribute significantly to the development of POD, the molecular, genetic mechanisms of POD in cardiac surgery patients, along with potential metabolomic diagnostic markers, remain inadequately understood. In this study, blood plasma was collected from a group of patients over 65 years old after cardiac surgery involving artificial circulation. The collected samples were analyzed for sphingomyelin content and quantity using high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS) methods. The analysis revealed four significantly different sphingomyelin contents in patients with POD compared to those who did not develop POD (control group). Employing gene network reconstruction, we perceived a set of 82 regulatory enzymes affiliated with the genetic coordination of the sphingolipid metabolism pathway. Within this set, 47 are assumed to be regulators of gene expression, governing the transcription of enzymes pivotal to the metabolic cascade. Complementing this, an additional assembly of 35 regulators are considered to be regulators of activity, degradation, and translocation dynamics of enzymes integral to the aforementioned pathway. Analysis of the overrepresentation of diseases with which these regulatory proteins are associated showed that the regulators can be categorized into two groups, associated with cardiovascular pathologies (CVP) and neuropsychiatric diseases (NPD), respectively. The regulators associated with CVP are expectedly related to the effects on myocardial tissue during surgery. It is hypothesized that dysfunction of NPD-associated regulators may specifically account for the development of POD after cardiac surgery. Thus, the identified regulatory genes may provide a basis for planning further experiments, in order to study disorders at the level of expression of these genes, as well as impaired function of proteins encoded by them in patients with POD. The identified significant sphingolipids can be considered as potential markers of POD.

Molecular-genetic pathways of hepatitis C virus regulation of the expression of cellular factors PREB and PLA2G4C, which play an important role in virus replication

The participants of Hepatitis C virus (HCV) replication are both viral and host proteins. Therapeutic approaches based on activity inhibition of viral non-structural proteins NS3, NS5A, and NS5B are undergoing clinical trials. However, rapid mutation processes in the viral genome and acquisition of drug resistance to the existing drugs remain the main obstacles to fighting HCV. Identifying the host factors, exploring their role in HCV RNA replication, and studying viral effects on their expression is essential for understanding the mechanisms of viral replication and developing novel, effective curative approaches. It is known that the host factors PREB (prolactin regulatory element binding) and PLA2G4C (cytosolic phospholipase A2 gamma) are important for the functioning of the viral replicase complex and the formation of the platforms of HCV genome replication. The expression of PREB and PLA2G4C was significantly elevated in the presence of the HCV genome. However, the mechanisms of its regulation by HCV remain unknown. In this paper, using a text-mining technology provided by ANDSystem, we reconstructed and analyzed gene networks describing regulatory effects on the expression of PREB and PLA2G4C by HCV proteins. On the basis of the gene network analysis performed, we put forward hypotheses about the modulation of the host factors functions resulting from protein-protein interaction with HCV proteins. Among the viral proteins, NS3 showed the greatest number of regulatory linkages. We assumed that NS3 could inhibit the function of host transcription factor (TF) NOTCH1 by protein-protein interaction, leading to upregulation of PREB and PLA2G4C. Analysis of the gene networks and data on differential gene expression in HCV-infected cells allowed us to hypothesize further how HCV could regulate the expression of TFs, the binding sites of which are localized within PREB and PLA2G4C gene regions. The results obtained can be used for planning studies of the molecular-genetic mechanisms of viral-host interaction and searching for potential targets for anti-HCV therapy.

Postoperative delirium in geriatric patients with hip fractures

Postoperative delirium (POD) is a frequent complication in geriatric patients with hip fractures, which is linked to poorer functional recovery, longer hospital stays, and higher short-and long-term mortality. Patients with increased age, preoperative cognitive impairment, comorbidities, perioperative polypharmacy, and delayed surgery are more prone to develop POD after hip fracture surgery. In this narrative review, we outlined the latest findings on postoperative delirium in geriatric patients with hip fractures, focusing on its pathophysiology, diagnosis, prevention, and treatment. Perioperative risk prediction, avoidance of certain medications, and orthogeriatric comprehensive care are all examples of effective interventions. Choices of anesthesia technique may not be associated with a significant difference in the incidence of postoperative delirium in geriatric patients with hip fractures. There are few pharmaceutical measures available for POD treatment. Dexmedetomidine and multimodal analgesia may be effective for managing postoperative delirium, and adverse complications should be considered when using antipsychotics. In conclusion, perioperative risk intervention based on orthogeriatric comprehensive care is the most effective strategy for preventing postoperative delirium in geriatric patients with hip fractures.

Preoperative homocysteine modifies the association between postoperative C-reactive protein and postoperative delirium

Background

Homocysteine and C-reactive protein (CRP) may serve as biomarkers of postoperative delirium. We set out to compare the role of blood concentration of homocysteine versus CRP in predicting postoperative delirium in patients.

Materials and methods

In this prospective observational cohort study, the plasma concentration of preoperative homocysteine and postoperative CRP was measured. Delirium incidence and severity within 3 days postoperatively were determined using the Confusion Assessment Method and Confusion Assessment Method-Severity algorithm.

Results

Of 143 participants [69% female, median (interquartile range, 25th–75th) age of 71 (67–76) years] who had knee or hip surgery under general anesthesia, 44 (31%) participants developed postoperative delirium. Postoperative plasma concentration of CRP was associated with postoperative delirium incidence [adjusted odds ratio (OR) per one standard deviation change in CRP: 1.51; 95% Confidence Interval (CI): 1.05, 2.16; P = 0.026], and severity [in which each one standard deviation increase in postoperative CRP was associated with a 0.47 point (95% CI: 0.18–0.76) increase in the severity of delirium, P = 0.002] after adjusting age, sex, preoperative Mini-Mental State Examination score and the days when postoperative CRP was measured. A statistically significant interaction (adjusted P = 0.044) was also observed, in which the association between postoperative plasma concentration of CRP and postoperative delirium incidence was stronger in the participants with lower preoperative plasma concentrations of homocysteine compared to those with higher preoperative levels.

Conclusion

Pending validation studies, these data suggest that preoperative plasma concentration of homocysteine modifies the established association between postoperative plasma concentration of CRP and postoperative delirium incidence.

Cytokine profiles in intensive care unit delirium

Background

Neuroinflammation causing disruption of the blood-brain barrier and immune cell extravasation into the brain parenchyma may cause delirium; however, knowledge of the exact pathophysiologic mechanism remains incomplete. The purpose of our study was to determine whether cytokine profiles differ depending on whether delirium occurs in the setting of sepsis, coronavirus disease 2019 (COVID-19), or recent surgery.

Methods

This prospective observational cohort study involved 119 critically ill patients admitted to a multidisciplinary intensive care unit (ICU) during 2019 and 2020. Delirium was identified using the validated confusion assessment method for the ICU. Multiple delirium risk factors were collected daily including clinical characteristics, hospital course, lab values, vital signs, surgical exposure, drug exposure, and COVID-19 characteristics. Serums samples were collected within 12 hours of ICU admission and cytokine levels were measured.

Results:

The following proinflammatory cytokines were elevated in our delirium population: tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-18, C-C motif ligand (CCL) 2, CCL3, C-X-C motif chemokine ligand (CXCL)1, CXCL10, IL-8, IL-1 receptor antagonist, and IL-10. Analysis of relative cytokine levels in those patients that developed delirium in the setting of sepsis, COVID-19, and recent surgery showed elevations of CCL2, CXCL10, and TNF-α in both the sepsis and COVID-19 group in comparison to the postsurgical population. In the postsurgical group, granulocyte colony-stimulating factor was elevated and CXCL10 was decreased relative to the opposing groups.

Conclusions

We identify several cytokines and precipitating factors known to be associated with delirium. However, our study suggests that the cytokine profile associated with delirium is variable and contingent upon delirium precipitating factors.

The Influence of Orthopedic Surgery on Circulating Metabolite Levels, and their Associations with the Incidence of Postoperative Delirium

The mechanisms underlying the occurrence of postoperative delirium development are unclear and measurement of plasma metabolites may improve understanding of its causes. Participants (n = 54) matched for age and gender were sampled from an observational cohort study investigating postoperative delirium. Participants were ≥65 years without a diagnosis of dementia and presented for primary elective hip or knee arthroplasty. Plasma samples collected pre- and postoperatively were grouped as either control (n = 26, aged: 75.8 ± 5.2) or delirium (n = 28, aged: 76.2 ± 5.7). Widespread changes in plasma metabolite levels occurred following surgery. The only metabolites significantly differing between corresponding control and delirium samples were ornithine and spermine. In delirium cases, ornithine was 17.6% higher preoperatively, and spermine was 12.0% higher postoperatively. Changes were not associated with various perioperative factors. In binary logistic regression modeling, these two metabolites did not confer a significantly increased risk of delirium. These findings support the hypothesis that disturbed polyamine metabolism is an underlying factor in delirium that warrants further investigation.

Early Serum Metabolism Profile of Post-operative Delirium in Elderly Patients Following Cardiac Surgery With Cardiopulmonary Bypass

Background

Cardiac surgery with cardiopulmonary bypass (CPB) is considered to be one of the surgical types with the highest incidence of post-operative delirium (POD). POD has been associated with a prolonged intensive care and hospital stay, long-term neurocognitive deterioration, and increased mortality. However, the specific pathogenesis of POD is still unclear. Untargeted metabolomics techniques can be used to understand the changes of serum metabolites in early POD to discover the relationship between serum metabolites and disease.

Materials and Methods

The present study recruited 58 elderly patients undergoing cardiac surgery with CPB. Serum was collected within the first 24 h after surgery. The Confusion Assessment Method (CAM) and ICU-CAM assessments were used to identify patients who experienced POD. All patients with normal post-operative cognitive assessment were included in the non-POD groups. Moreover, we collected serum from 20 healthy adult volunteers. We performed untargeted analyses of post-operative serum metabolites in all surgical groups, as well as serum metabolites in healthy non-surgical adults by using liquid chromatography mass spectrometry (LC/MS) and analyzed metabolic profiles and related metabolites.

Results

The probability of POD after cardiac surgery were 31%. There were statistically significant differences in post-operative mechanical ventilation time, ICU stay time and post-operative hospital stay between POD and non-POD group (P < 0.05). And ICU stay time was an independent risk factor for POD. The analysis revealed that a total of 51 differentially expressed metabolites (DEMs) were identified by comparing the POD and non-POD group, mostly lipids and lipid-like molecules. Three phosphatidylinositol (PI) were down-regulated in POD group, i.e., PI [18:0/18:2 (9Z, 12Z)], PI [20:4 (8Z, 11Z, 14Z, 17Z)/18:0], and PI [18:1 (9Z)/20:3 (8Z, 11Z, 14Z)]. The receiver operating characteristic (ROC) curve analysis showed that three kinds of PI metabolites had the highest area under the curve (AUC), which were 0.789, 0.781, and 0.715, respectively. Correlation analysis showed that the expression of three PIs was negatively correlated with the incidence of POD.

Conclusion

Our findings suggest that lipid metabolism plays an important role in the serum metabolic profile of elderly patients with POD in the early post-operative period. Low serum lipid metabolic PI was associated with incidence of POD in elderly following cardiac bypass surgery, which may provide new insights into the pathogenesis of POD.

Early Intervention of Perioperative Delirium in Older Patients (>60 years) with Hip Fracture: A Randomized Controlled Study

Objective

To explore the effect of early intervention for perioperative delirium in older (> 60 years) hip fracture patients.

Methods

This prospective study enrolled hip fracture patients aged ≥60 years who were admitted into our hospital between July 2011 and August 2019. Hip fractures were classified according to the Arbeitsgemeinschaft für Osteo‐synthesefragen (AO) classification. This study included patients with isolated hip fracture and excluded patients with pathological or peri prosthetic fracture or patients with multiple traumatic injuries and high‐energy trauma. They were randomized to receive conventional orthopedic care group (n = 65) or comprehensive orthopedic care group including preoperative psychological counseling and preventative risperidone (n = 63). Daily assessment was based on patient interview with the CAM‐CR, and delirium was diagnosed by the Delirium Rating Scale (DRS‐R‐98). The rate, severity and duration of perioperative delirium and the length of postoperative stay were analyzed.

Results

Totally 200 patients were screened for eligibility. Twenty patients were excluded due to alcohol abuse and 40 were excluded because of brain lesions on head CT. In addition, 12 patients were excluded because of impaired cognition. Finally 128 patients were enrolled. Their mean age was 75.3 ± 2.2 years for the comprehensive orthopedic care group and 73.5 ± 6.1 years for the conventional orthopedic care group, and 53.9% of the patients were female. Sixty‐eight (53.1%) patients had intertrochanteric fracture, 39.8% patients had femoral head fracture, and 7.0% patients had subtrochanteric fracture. In addition, 58.6% patients underwent internal fixation and 41.4% patients received arthroplasty. In this study, 63 patients were randomized to the comprehensive orthopedic care group and 65 patients to the conventional orthopedic care group. The two groups were comparable in demographic and baseline characteristics (P > 0.05). The rate of perioperative delirium was significantly lower in the comprehensive care group vs the conventional care group (15.9% vs. 30.8%; P < 0.05). The comprehensive care group had significantly reduced length of postoperative hospital stay vs the conventional care group (11.3 ± 2.5 days vs. 14.2 ± 2.2 days, P < 0.01). The mean DRS‐R‐98 score was 7.1 ± 2.7 for the comprehensive care group, and was significantly lower than that of the conventional orthopedic care group (11.2 ± 3.0; P < 0.05).

Conclusions

Our early intervention may reduce the incidence of perioperative delirium in elderly hip fracture patients (>60 years).

Review of Postoperative Delirium in Geriatric Patients After Hip Fracture Treatment

Introduction

Postoperative delirium (POD) is a serious complication occurring in 4–53.3% of geriatric patients undergoing surgeries for hip fracture. Incidence of hip fractures is projected to grow 11.9% from 258,000 in 2010 to 289,000 in 2030 based on 1990 to 2010 data. As prevalence of hip fractures is projected to increase, POD is also anticipated to increase.

Signficance

Postoperative delirium remains the most common complication of emergency hip fracture surgery leading to high morbidity and mortality rates despite significant research conducted regarding this topic. This study reviews literature from 1990 to 2021 regarding POD in geriatric hip fracture management.

Results

Potentially modifiable and non-modifiable risk factors for developing POD include, but are not limited to, male gender, older age, multiple comorbidities, specific comorbidities (dementia, cognitive impairment, diabetes, vision impairment, and abnormal blood pressure), low BMI, preoperative malnutrition, low albumin, low hematocrit, blunted preoperative cytokines, emergency surgery, time to admission and surgery, preoperative medical treatment, polypharmacy, delirium-inducing medications, fever, anesthesia time, and sedation depth and type. Although the pathophysiology remains unclear, the leading theories suggest neurotransmitter imbalance, inflammation, and electrolyte or metabolic derangements as the underlying cause of POD. POD is associated with increased length of hospital stay, cost, morbidity, and mortality. Prevention and early recognition are key factors in managing POD. Methods to reduce POD include utilizing interdisciplinary teams, educational programs for healthcare professionals, reducing narcotic use, avoiding delirium-inducing medications, and multimodal pain control.

Conclusion

While POD is a known complication after hip fracture surgery, further exploration in prevention is needed. Early identification of risk factors is imperative to prevent POD in geriatric patients. Early prevention will enhance delivery of health care both pre- and post-operatively leading to the best possible surgical outcome and better quality of life after hip fracture treatment.

Risk of Dementia in Patients Who Underwent Surgery under Neuraxial Anesthesia: A Nationwide Cohort Study

The incidence of dementia in patients with surgery under neuraxial anesthesia and the possibility of surgery under neuraxial anesthesia as a risk factor for dementia were investigated. We performed a retrospective matched cohort study with nationwide, representative cohort sample data of the Korean National Health Insurance Service in South Korea between 1 January 2003, and 31 December 2004. The participants were divided into control (n = 4488) and neuraxial groups (n = 1122) using propensity score matching. After 9 years of follow-up, the corresponding incidences of dementia were 11.5 and 14.8 cases per 1000 person-years. The risk of dementia in the surgery under neuraxial group was 1.44-fold higher (95% confidence interval [95%CI], 1.17-1.76) than that in the control group. In the subgroup analysis of dementia, the risk of Alzheimer's disease in those who underwent surgery under neuraxial anesthesia was 1.48-fold higher (95%CI, 1.17-1.87) than that in those who did not undergo surgery under anesthesia. Our findings suggest that patients who underwent surgery under neuraxial anesthesia had a higher risk of dementia and Alzheimer's disease than those who did not undergo surgery under neuraxial anesthesia.

Predictive Value of Preoperative Profiling of Serum Metabolites for Emergence Agitation After General Anesthesia in Adult Patients

Background: Emergence agitation (EA) in adult patients under general anesthesia leads to increased postoperative complications and heavy medical burden. Unfortunately, its pathogenesis has not been clarified until now. The purpose of the present study was to explore the relationship between preoperative serum metabolites and EA. Methods: We used an untargeted metabolic analysis method to investigate the different metabolomes in the serum of EA patients and non-EA patients undergoing elective surgical procedures after the induction of general anesthesia. A Richmond Agitation-Sedation Scale score ≥ +2 was diagnosed as EA during postoperative emergence. Non-EA patients were matched with EA patients according to general characteristics. Preoperative serum samples of the two groups were collected to investigate the association between serum metabolites and EA development. Results: The serum samples of 16 EA patients with 34 matched non-EA patients were obtained for metabolic analysis. After screening and alignment with databases, 31 altered metabolites were detected between the two groups. These metabolites were mainly involved in the metabolism of lipids, purines, and amino acids. Analyses of receiver-operating characteristic curves showed that the preoperative alterations of choline, cytidine, glycerophosphocholine, L-phenylalanine, oleamide, and inosine may be associated with adult EA. Conclusion: Multiple metabolic abnormalities (including those for lipids, purines, and amino acids) and other pathological processes (e.g., neurotransmitter imbalance and oxidative stress) may contribute to EA. Several altered metabolites in serum before surgery may have predictive value for EA diagnosis. This study might afford new metabolic clues for the understanding of EA pathogenesis.

Metabolomics Analysis of the Development of Sepsis and Potential Biomarkers of Sepsis-Induced Acute Kidney Injury

Sepsis-induced acute kidney injury (SI-AKI) is a serious condition in critically ill patients. Currently, the diagnosis is based on either elevated serum creatinine levels or oliguria, which partially contribute to delayed recognition of AKI. Metabolomics is a potential approach for identifying small molecule biomarkers of kidney diseases. Here, we studied serum metabolomics alterations in rats with sepsis to identify early biomarkers of sepsis and SI-AKI. A rat model of SI-AKI was established by intraperitoneal injection of lipopolysaccharide (LPS). Thirty Sprague-Dawley (SD) rats were randomly divided into the control (CT) group and groups treated for 2 hours (LPS2) and 6 hours (LPS6) with LPS (10 rats per group). Nontargeted metabolomics screening was performed on the serum samples from the control and SI-AKI groups. Combined multivariate and univariate analysis was used for pairwise comparison of all groups to identify significantly altered serum metabolite levels in early-stage AKI in rats with sepsis. Orthogonal partial least squares discriminant analysis (OPLS-DA) showed obvious separation between the CT and LPS2 groups, CT and LPS6 groups, and LPS2 and LPS6 groups. All comparisons of the groups identified a series of differential metabolites according to the threshold defined for potential biomarkers. Intersections and summaries of these differential metabolites were used for pathway enrichment analysis. The results suggested that sepsis can cause an increase in systemic aerobic and anaerobic metabolism, an impairment of the oxygen supply, and uptake and abnormal fatty acid metabolism. Changes in the levels of malic acid, methionine sulfoxide, and petroselinic acid were consistently measured during the progression of sepsis. The development of sepsis was accompanied by the development of AKI, and these metabolic disorders are directly or indirectly related to the development of SI-AKI.

Risk factors of postoperative delirium in the knee and hip replacement patients: a systematic review and meta-analysis

BACKGROUND

The risk factors of postoperative delirium (POD), a serious while preventable complication, developed by patients undergoing knee and replacement surgery are still under investigation. In this systematic review and meta-analysis, we identified risk factors associated with POD in knee and hip replacement.

METHODS

PubMed, Ovid MEDLINE, and Ovid EMBASE were used to identify original researches. The studies evaluating the risk factors of POD after knee and hip replacement were reviewed, and the qualities of the included studies were assessed with Newcastle-Ottawa Scale. Data were extracted, pooled, and a meta-analysis was completed RESULT: Twenty-two studies were finally included with a total of 11934 patients who underwent knee or hip replacement and 1841 developed POD with an incidence of 17.6% (95% confidential interval (CI) 13.2-22.0%). Eighteen significant risk factors were identified including advanced age (odds ratio (OR) 1.15 95% CI 1.08-1.22), cognitive impairment (OR 6.84, 95% CI 3.27-14.33), history of cerebrovascular events (OR 2.51, 95% CI 1.28-4.91), knee replacement (OR 1.42, 95% CI 1.00-2.02), blood loss (standardized mean difference (SMD) 0.30, 95% CI 0.15-0.44), dementia (OR 3.09, 95% CI 2.10-4.56), neurologic disorders (OR 2.26, 95% CI 1.23-4.15), psychiatric illness (OR 2.74, 95% CI 1.34-5.62), and obstructive sleep apnea (OR 4.17, 95% CI 1.72-10.09) along with several comorbidity evaluation scores and laboratory markers.

CONCLUSION

We identified risk factors consistently associated with the incidence of POD in knee and hip replacement. Strategies and interventions should be implemented to the patients receiving knee or hip replacement with potential risk factors identified in this meta-analysis.

Targeted metabolomics analysis of postoperative delirium

Postoperative delirium is the most common complication among older adults undergoing major surgery. The pathophysiology of delirium is poorly understood, and no blood-based, predictive markers are available. We characterized the plasma metabolome of 52 delirium cases and 52 matched controls from the Successful Aging after Elective Surgery (SAGES) cohort (N = 560) of patients ≥ 70 years old without dementia undergoing scheduled major non-cardiac surgery. We applied targeted mass spectrometry with internal standards and pooled controls using a nested matched case-control study preoperatively (PREOP) and on postoperative day 2 (POD2) to identify potential delirium risk and disease markers. Univariate analyses identified 37 PREOP and 53 POD2 metabolites associated with delirium and multivariate analyses achieved significant separation between the two groups with an 11-metabolite prediction model at PREOP (AUC = 83.80%). Systems biology analysis using the metabolites with differential concentrations rendered "valine, leucine, and isoleucine biosynthesis" at PREOP and "citrate cycle" at POD2 as the most significantly enriched pathways (false discovery rate < 0.05). Perturbations in energy metabolism and amino acid synthesis pathways may be associated with postoperative delirium and suggest potential mechanisms for delirium pathogenesis. Our results could lead to the development of a metabolomic delirium predictor.