The stress response to surgery and postoperative delirium: evidence of hypothalamic-pituitary-adrenal axis hyperresponsiveness and decreased suppression of the GH/IGF-1 Axis

Low peripheral levels of insulin growth factor-1 are associated with high incidence of delirium among elderly patients: A systematic review and meta-analysis

INTRODUCTION

Delirium, a serious condition observed in critically ill patients, clinically presents with impaired cognition and consciousness. The relationship between delirium and peripheral levels of insulin growth factor-1 (IGF-1) is unclear. Thus we conducted a meta-analysis to address this issue.

METHODS

Seven major electronic databases were searched from inception until October 2, 2017 to obtain relevant clinical variables to compare the difference in IGF-1 levels between delirious and non-delirious elderly in-patients. A random effects meta-analysis was conducted.

RESULTS

We studies 10 articles involving 294 delirious patients (mean age 73.0 years) and 604 non-delirious patients (mean age 76.9 years). We found that peripheral levels of IGF-1 in patients with delirium were significantly lower than in those without delirium (Hedges' g = -0.209, 95% confidence interval [CI] = -0.393 to -0.026, p = 0.025). Meta-regression analyses found that no variables such as percentage of cognitive impairment, mean age, and female proportion contribute to heterogeneity in terms of the entire population.

CONCLUSIONS

Our data suggests that lower peripheral levels of IGF-1 could be associated with a higher incidence of delirium among elderly patients. Further prospective studies with larger sample sizes are needed to investigate the association between peripheral levels of IGF-1 and delirium.

Intraoperative electroencephalogram suppression at lower volatile anaesthetic concentrations predicts postoperative delirium occurring in the intensive care unit

BACKGROUND

Postoperative delirium is a common complication associated with increased morbidity and mortality. A recently-reported association between intraoperative electroencephalogram suppression and postoperative delirium might be mediated in some patients by a heightened sensitivity to volatile anaesthetics.

METHODS

This retrospective cohort study included 618 elective surgery patients with planned intensive care unit admission, who also received intraoperative electroencephalogram monitoring and had delirium assessments documented in the medical record. Sensitivity to volatile anaesthetics was assessed using a mixed effects model predicting the likelihood of electroencephalogram suppression at each time point based on the current end-tidal anaesthetic concentration. Patients with a random intercept above the population median (electroencephalogram suppression at lower anaesthetic concentrations) were classified as having heightened sensitivity to volatile anaesthetics. Delirium was defined as a positive Confusion Assessment Method for the Intensive Care Unit assessment anytime in the first five postoperative days.

RESULTS

Postoperative delirium was observed in 162 of 618 patients (26%). Patients who experienced electroencephalogram suppression at lower volatile anaesthetic concentrations had a higher incidence of postoperative delirium [109/309 (35%)] than other patients [53/309 (17%)] [unadjusted odds ratio 2.63; 95% confidence interval (CI), 1.81-3.84, P<0.001]. This association remained significant after adjusting for patient characteristics, surgical variables, and duration of electroencephalogram suppression (adjusted odds ratio 2.13; 95% CI 1.24-3.65, P=0.006).

CONCLUSIONS

These data support the hypothesis that patients with electroencephalogram suppression at lower volatile anaesthetic concentrations have an increased incidence of postoperative delirium. Such patients appear to exhibit a phenotype of anaesthetic sensitivity, which might predispose them to adverse cognitive outcomes.

Relationship between general anesthesia and Alzheimer disease: A protocol for a systematic review and meta-analysis

BACKGROUND

Alzheimer disease (AD) entails a long-term progressive decline in the cognitive ability to think and remember, and it has become a major concern for patients receiving surgery and anesthesia. However, studies investigating the relationship between general anesthesia and AD have yielded inconsistent results. Therefore, we plan to perform a systematic review and meta-analysis to determine the relationship between general anesthesia and AD, and to verify whether general anesthesia is an independent risk factor for AD.

METHODS

A systematic and comprehensive search will be performed using MEDLINE, EMBASE, and Google scholar from their inception to August 2017. Peer-reviewed cohort and case-control studies including nested case-control studies reporting the relationship between general anesthesia and AD will be eligible for inclusion. The quality of included studies will be assessed using the Newcastle-Ottawa scale. Heterogeneity of estimates across studies as well as publication bias will be assessed. This systematic review and meta-analysis will be performed according to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines and reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines. All statistical analyses will be conducted using the Stata SE version 15.0.

RESULTS

The results of this systematic review and meta-analysis will be published in a peer-reviewed journal.

CONCLUSION

Our study will provide the evidence for the relationship between general anesthesia and dementia. The review will benefit patients and anesthesiologists, surgeons, and policymakers.

ETHICS AND DISSEMINATION

Ethical approval and informed consent are not required, as the study will be a literature review and will not involve direct contact with patients or alterations to patient care.

TRIAL REGISTRATION

The protocol for this review has been registered in the PROSPERO network (registration number: CRD42017073790).

Preoperative C-Reactive Protein as a Risk Factor for Postoperative Delirium in Elderly Patients Undergoing Laparoscopic Surgery for Colon Carcinoma

Background

Postoperative delirium (POD) is a very common complication in operative disciplines, especially in those elderly patients after cardiac surgery. This study aimed to investigate the relationship between C-reactive protein (CRP) and POD in elderly patients undergoing laparoscopic surgery for colon carcinoma.

Methods

160 elderly patients scheduled to undergo selective laparoscopic surgery for colon carcinoma were prospectively recruited in this present study. The preoperative demographic and medical characteristics, intraoperative variables, and postoperative complications were all recorded in detail. POD assessment was performed once a day for the first 3 days and at 7th day after surgery, respectively. CRP concentrations preoperatively and on postoperative days 1, 2, and 3 were measured by using human enzyme linked immunosorbent assay (ELISA).

Results

Of all the 160 enrolled patients, 39 had suffered POD with a POD incidence of 24.4% within the first week after the operation. The univariate analysis and multiple logistic regression analysis suggested preoperative CRP concentrations as the only independent predicator for POD in patients undergoing laparoscopic surgery for colon carcinoma (OR: 5.87; 95% CI: 2.22-11.4; P = 0.018).

Conclusions

This present study highlighted the predictive role of preoperative CRP concentrations for POD in elderly patients undergoing laparoscopic surgery for colon carcinoma.

High C-Reactive Protein Predicts Delirium Incidence, Duration, and Feature Severity After Major Noncardiac Surgery

OBJECTIVES

To examine associations between the inflammatory marker C-reactive protein (CRP) measured preoperatively and on postoperative day 2 (POD2) and delirium incidence, duration, and feature severity.

DESIGN

Prospective cohort study.

SETTING

Two academic medical centers.

PARTICIPANTS

Adults aged 70 and older undergoing major noncardiac surgery (N = 560).

MEASUREMENTS

Plasma CRP was measured using enzyme-linked immunosorbent assay. Delirium was assessed from Confusion Assessment Method (CAM) interviews and chart review. Delirium duration was measured according to number of hospital days with delirium. Delirium feature severity was defined as the sum of CAM-Severity (CAM-S) scores on all postoperative hospital days. Generalized linear models were used to examine independent associations between CRP (preoperatively and POD2 separately) and delirium incidence, duration, and feature severity; prolonged hospital length of stay (LOS, >5 days); and discharge disposition.

RESULTS

Postoperative delirium occurred in 24% of participants, 12% had 2 or more delirium days, and the mean ± standard deviation sum CAM-S was 9.3 ± 11.4. After adjusting for age, sex, surgery type, anesthesia route, medical comorbidities, and postoperative infectious complications, participants with preoperative CRP of 3 mg/L or greater had a risk of delirium that was 1.5 times as great (95% confidence interval (CI) = 1.1-2.1) as that of those with CRP less than 3 mg/L, 0.4 more delirium days (P < .001), more-severe delirium (3.6 CAM-S points higher, P < .001), and a risk of prolonged LOS that was 1.4 times as great (95% CI = 1.1-1.8). Using POD2 CRP, participants in the highest quartile (≥235.73 mg/L) were 1.5 times as likely to develop delirium (95% CI = 1.0-2.4) as those in the lowest quartile (≤127.53 mg/L), had 0.2 more delirium days (P < .05), and had more severe delirium (4.5 CAM-S points higher, P < .001).

CONCLUSION

High preoperative and POD2 CRP were independently associated with delirium incidence, duration, and feature severity. CRP may be useful to identify individuals who are at risk of developing delirium.

Higher C-Reactive Protein Levels Predict Postoperative Delirium in Older Patients Undergoing Major Elective Surgery: A Longitudinal Nested Case-Control Study

BACKGROUND

Delirium is a common, morbid, and costly postoperative complication. We aimed to identify blood-based postoperative delirium markers in a nested case-control study of older surgical patients using a proteomics approach followed by enzyme-linked immunosorbent assay (ELISA) validation.

METHODS

The Successful Aging after Elective Surgery study enrolled dementia-free adults ≥70 years old undergoing major scheduled noncardiac surgery (N = 566; 24% delirium). Plasma was collected at four time points: preoperative, postanesthesia care unit, postoperative day 2, and 1 month postoperative. Matched pairs were selected for the independent discovery (39 pairs) and replication cohorts (36 pairs), which were subsequently combined into the pooled cohort (75 pairs). Isobaric tags for relative and absolute quantitation-based relative quantitation mass spectrometry proteomics were performed to identify the strongest delirium-related protein, which was selected for ELISA validation. Using the ELISA results, statistical analyses using nonparametric signed rank tests were performed in all cohorts examining the association between the identified protein and delirium.

RESULTS

C-reactive protein emerged from the proteomics analysis as the strongest delirium-related protein. Validation by ELISA confirmed that compared with controls, cases had significantly higher C-reactive protein levels in the discovery, replication, and pooled cohorts at the preoperative (median paired difference [MPD] 1.97 mg/L [p < .05], 0.29 mg/L, 1.56 mg/L [p < .01]), postanesthesia care unit (MPD 2.83 mg/L, 2.22 mg/L [p < .05], 2.53 mg/L [p < .01]) and postoperative day 2 (MPD 71.97 mg/L [p < .01], 35.18 mg/L [p < .05], 63.76 mg/L [p < .01]) time points, but not 1 month postoperative (MPD 2.72 mg/L, -0.66 mg/L, 1.10 mg/L).

CONCLUSIONS

Elevated preoperative and postoperative plasma levels of C-reactive protein were associated with delirium, suggesting that a preinflammatory state and heightened inflammatory response to surgery are potential pathophysiologic mechanisms of delirium.

Regulator Versus Effector Paradigm: Interleukin-10 as Indicator of the Switching Response

The interleukin-10 (IL-10) is generally considered as the most important cytokine with anti-inflammatory properties and one of the key cytokines preventing inflammation-mediated tissue damage. In this respect, IL-10 producing cells play a crucial role in the outcome of infections, allergy, autoimmune reactions, tumor development, and transplant tolerance. Based on recent findings with regard to the mentioned clinical conditions, this review attempts to shed some light on the IL-10 functions, considering this cytokine as inherent inducer of the switching immunity. While acute infections and vaccinations are associated by IL-10 enhanced during few weeks, chronic parasitoses, tumor diseases, allergen-specific immunotherapy, transplants, and use of immune-suppressor drugs show an increased IL-10 level along months or years. With regard to autoimmune pathologies, the IL-10 increase is prevalently observed during early stages, whereas the successive stages are characterized by reaching of immune equilibrium independently to disease's activity. Together, these findings indicate that IL-10 is mainly produced during transient immune conditions and the persistent IL-10-related effect is the indication/prediction (and maybe effectuation) of the switching immunity. Actual knowledge emphasizes that any manipulation of the IL-10 response for treatment purposes should be considered very cautiously due to its potential hazards to the immune system. Probably, the IL-10 as potential switcher of immunity response should be used in association with co-stimulatory immune effectors that are necessary to determine the appropriate deviation during treatment of respective pathologies. Hopefully, further findings would open new avenues to study the biology of this "master switch" cytokine and its therapeutic potential.

Lack of Association between Pre-Operative Insulin-Like Growth Factor-1 and the Risk of Post-Operative Delirium in Elderly Chinese Patients

OBJECTIVE

Postoperative delirium (POD) is a highly prevalent complex neuropsychiatric syndrome in elderly patients. However, its pathophysiology is currently unknown. Early detection and prevention of POD is important; therefore, the aim of this study was to investigate the link between preoperative insulin growth factor 1 (IGF-1) levels in the serum and POD in the Chinese elderly patients.

METHODS

One hundred and three patients who were undergoing an orthopedic operation took part in the study. Preoperative serum IGF-1 levels were measured. POD was determined daily using the Confusion Assessment Method (CAM) and DSM-IV TR. Baseline serum IGF-1 levels were compared between patients who did and did not develop POD. Correlation coefficients were calculated to evaluate relationship between baseline characteristics and serum IGF-1 levels. The relationship between baseline biomarkers and delirium status was investigated using logistic regression analysis, adjusting for potential confounding variables.

RESULTS

Twenty-three patients developed POD. The POD group had lower MMSE scores and higher CCI scores and proportions of acute admission. Preoperative serum IGF-1 levels were correlated with MMSE scores and age (MMSE: r=0.230, p<0.05; age: r=-0.419, p<0.001). Baseline serum IGF-1 levels did not differ between patients who did and did not develop POD, even after adjusting for potential confounding factors, MMSE score, and age.

CONCLUSION

No association was found between preoperative IGF-1 levels and POD, suggesting that they are not direct biomarkers of the incidence of POD among the Chinese elderly population. Further research with larger sample sizes is warranted to clarify the relationship.

Prevalence and risk factors of postoperative delirium in elderly hip fracture patients

Objective

To explore the risk factors associated with postoperative delirium (PD) in elderly patients following total hip arthroplasty (THA) for hip fracture.

Methods

This prospective study enrolled elderly patients (≥ 65 years) with hip fractures who underwent THA under general anaesthesia, and who had a complete set of postoperative observations. Detailed medical history and perioperative characteristics were recorded. During the postoperative period, patients were assessed twice daily for PD using the Confusion Assessment Method.

Results

A total of 572 patients were eligible for inclusion in the study. Of these, 120 patients (21.0%) were diagnosed with PD and 452 patients (79.0%) did not experience PD. Multivariate stepwise logistic regression analyses showed that older age, a history of stroke, lower albumin, higher blood glucose, higher total bilirubin, higher C-reactive protein, longer surgery duration and higher volume of red blood cell transfusions were independent risk factors for PD.

Conclusions

Correcting the modifiable risk factors might help prevent PD. Strategies might include nutritional support, tight blood glucose control, improvement of liver function, preoperative infection control and minimizing surgical injury or blood loss.

Anesthesia Exposure and Risk of Dementia and Alzheimer's Disease: A Prospective Study

OBJECTIVES

To evaluate the associations between anesthesia and dementia or Alzheimer's disease (AD) risk using prospectively collected data.

DESIGN

Cohort study.

PARTICIPANTS

Community-dwelling members of the Adult Changes in Thought cohort aged 65 and older and free of dementia at baseline (N = 3,988).

MEASUREMENTS

Participants self-reported all prior surgical procedures with general or neuraxial (spinal or epidural) anesthesia at baseline and reported new procedures every 2 years. People undergoing high-risk surgery with general anesthesia, other surgery with general anesthesia, and other surgery with neuraxial anesthesia exposures were compared with those with no surgery and no anesthesia. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for dementia and AD associated with time-varying lifetime and recent (past 5 years) anesthesia exposures.

RESULTS

At baseline, 254 (6%) people reported never having anesthesia; 248 (6%) had had one or more high-risk surgeries with general anesthesia, 3,363 (84%) had had one or more other surgeries with general anesthesia, and 123 (3%) had had one or more surgeries with neuraxial anesthesia. High-risk surgery with general anesthesia was not associated with greater risk of dementia (HR = 0.86, 95% CI = 0.58-1.28) or AD (HR = 0.95, 95% CI = 0.61-1.49) than no history of anesthesia. People with any history of other surgery with general anesthesia had a lower risk of dementia (HR = 0.63, 95% CI = 0.46-0.85) and AD (HR = 0.65, 95% CI = 0.46-0.93) than people with no history of anesthesia. There was no association between recent anesthesia exposure and dementia or AD.

CONCLUSION

Anesthesia exposure was not associated with of dementia or AD in older adults.

Association between Serum IGF-I levels and Postoperative Delirium in Elderly Subjects Undergoing Elective Knee Arthroplasty

Evidence is mixed for an association between serum insulin-like growth factor-I (IGF-I) levels and postoperative delirium (POD). The current study assessed preoperative serum IGF-I levels as a predictor of incident delirium in non-demented elderly elective knee arthroplasty patients. Preoperative serum levels of total IGF-I were measured using a commercially available Human IGF-I ELISA kit. POD incidence and severity were determined using DSM-IV criteria and the Delirium Rating Scale-Revised-98 (DRS-R98), respectively. Median IGF-I levels in delirious (62.6 ng/ml) and non-delirious groups (65.9 ng/ml) were not significantly different (p = 0.141). The ratio (95% CI) of geometric means, D/ND, was 0.86 (0.70, 1.06). The Hodges-Lehmann median difference estimate was 7.23 ng/mL with 95% confidence interval (−2.32, 19.9). In multivariate logistic regression analysis IGF-I level was not a significant predictor of incident POD after correcting for medical comorbidities. IGF-I levels did not correlate with DRS-R98 scores for delirium severity. In conclusion, we report no evidence of association between serum IGF-I levels and incidence of POD, although the sample size was inadequate for a conclusive study. Further efforts to investigate IGF-I as a delirium risk factor in elderly should address comorbidities and confounders that influence IGF-I levels.

Impact of multicomponent, nonpharmacologic interventions on perioperative cortisol and melatonin levels and postoperative delirium in elderly oral cancer patients

OBJECTIVE

To investigate the impact of multicomponent, nonpharmacologic interventions (MNI) on perioperative cortisol and melatonin levels, as well as postoperative delirium (PD), in elderly oral cancer patients.

METHODS

A total of 160 elderly oral cancer patients who underwent tumor resection surgery and completed our investigation were included in this study. The cancer patients were randomly divided into 2 groups: Group U or Group I. During the perioperative period, Group U received usual care, while Group I received MNI, which is based on usual care and aims to decrease the risk of PD. MNI focused on general geriatric approaches and supportive nursing care. On the day before surgery and the first three postoperative days, nocturnal (20:00-8:00) urine samples were collected. The melatonin sulfate and cortisol levels in the urine samples were determined. Moreover, the RASS (Richmond Agitation Sedation Scale), CAM-ICU (Confusion Assessment Method for the Intensive Care Unit) and QoR40 (40-item quality of recovery score) scores were dynamically monitored.

RESULTS

There were no significant differences in the general characteristics between the 2 groups. After surgery, the melatonin sulfate levels in the nocturnal urine of Group I were higher than those in Group U. The cortisol concentrations were lower in Group I compared to those in Group U. Group I achieved better postoperative RASS and QoR40 scores than Group U. Compared to Group U, Group I also experienced less PD (incidence and duration).

CONCLUSIONS

MNI ameliorated some postoperative disturbances regarding sleep and stress, decreased the incidence of PD and improved recovery quality.

Anesthesia, surgical stress, and "long-term" outcomes

An increasing body of evidence shows that the choice of anesthetic can strongly influence more than simply the quality of anesthesia. Regional and general anesthesia have often been compared to ascertain whether one provides benefits through dampening the stress response or harms by accelerating cancer progression. Regional anesthesia offers considerable advantages, by suppressing cortisol and catecholamine levels and reducing muscle breakdown postoperatively. It also has less immunosuppressive effect and potentially reduces the proinflammatory cytokine response. As such, vital organ functions (e.g., brain and kidney) may be better preserved with regional anesthetics, however, further study is needed. Volatile general anesthetics appear to promote cancer malignancy in comparison to regional and intravenous general anesthetics, and reduce the body's ability to act against cancer cells by suppression of natural killer cell activity. There is not sufficient evidence to support an alteration of current clinical practice, however, further research into this area is warranted due to the potential implications elicited by current studies.

Postoperative Delirium in the Geriatric Patient

Postoperative delirium, a common complication in older surgical patients, is independently associated with increased morbidity and mortality. Patients older than 65 years receive greater than one-third of the more than 40 million anesthetics delivered yearly in the United States. This number is expected to increase with the aging of the population. Thus, it is increasingly important that perioperative clinicians who care for geriatric patients have an understanding of the complex syndrome of postoperative delirium.

Biomarkers of postoperative delirium and cognitive dysfunction

Elderly surgical patients frequently experience postoperative delirium (POD) and the subsequent development of postoperative cognitive dysfunction (POCD). Clinical features include deterioration in cognition, disturbance in attention and reduced awareness of the environment and result in higher morbidity, mortality and greater utilization of social financial assistance. The aging Western societies can expect an increase in the incidence of POD and POCD. The underlying pathophysiological mechanisms have been studied on the molecular level albeit with unsatisfying small research efforts given their societal burden. Here, we review the known physiological and immunological changes and genetic risk factors, identify candidates for further studies and integrate the information into a draft network for exploration on a systems level. The pathogenesis of these postoperative cognitive impairments is multifactorial; application of integrated systems biology has the potential to reconstruct the underlying network of molecular mechanisms and help in the identification of prognostic and diagnostic biomarkers.

IGF-I in major depression and antidepressant treatment response

We analyzed insulin-like growth factor I (IGF-I) in serum of 78 inpatients with depression and 92 healthy controls. Patients were selected according to remission status after 6 weeks of antidepressant treatment with remission defined by Hamilton depression rating scale (HAM-D) 21-item score <10 (39 remitters and 39 non-remitters). IGF-I was analyzed in patients at admission and after 6 weeks of psychopharmacological treatment. IGF-I levels were compared between patients and controls and between remitters and non-remitters with general linear model using age, gender, and body mass index as covariates. In patients, IGF-I levels were significantly higher at admission (p=3.29E-04) and in week 6 (p=0.002) compared to controls. Furthermore, non-remitters showed significantly higher IGF-I levels at admission (p=0.046) and a trend for higher IGF-I levels in week 6 (p=0.11) compared to remitters. In remitters change in IGF-I levels during treatment was significantly correlated with change in cortisol levels (p=0.019). A genetic association analysis of polymorphisms in 10 genes contributing to the IGF-I system (IGF1, IGF1R, IGFBP1 to IGFBP7, and IGFBPL1) in the currently largest genetic databases for major depression (Psychiatric Genomics Consortium) revealed nominal associations with susceptibility for depression and treatment response, although results did not remain significant after multiple testing correction. In our study, elevated IGF-I levels were significantly associated with depression and impaired treatment response. Based on these findings IGF-I signaling could play a role in the pathophysiology of depression and could possibly influence the response to antidepressant treatment.

Yokukansan, a traditional Japanese medicine, decreases head-twitch behaviors and serotonin 2A receptors in the prefrontal cortex of isolation-stressed mice

ETHNOPHARMACOLOGICAL RELEVANCE

Yokukansan, a traditional Japanese (Kampo) medicine, has recently been used to treat the behavioral and psychological symptoms of dementia (BPSD), including aggressiveness, excitability, and hallucination. The present study was designed to investigate the mechanisms underlying the ameliorative effects of yokukansan on BPSD using animals exhibiting hallucination-like behaviors. For this purpose, we initially examined whether chronic isolation stress increases the frequency of hallucination in response to a psychedelic drug. Using this animal model, we next examined the effects of yokukansan on drug-induced hallucination-like behaviors. Finally, we examined the density and mRNA levels of serotonin 2A (5-HT2A) receptors.

MATERIALS AND METHODS

Male mice were subjected to isolation stress for six weeks. Yokukansan was incorporated into food pellets, and administered to the mice for six weeks. In some experiments, yokukansan and each of seven constituent herbs were administered orally to the mice for the last two weeks during the six-week period of isolation stress. A 5-HT2A receptor agonist, 2,5-dimethoxy-4-iodoamphetamine (DOI, 2.5mg/kg), was injected into the mice, and head-twitch behaviors were quantified. The binding sites of 5-HT2A receptors on the plasma membrane of the prefrontal cortex (PFC) were assessed by a receptor-binding assay using tritium-labeled ketanserin, and the density and affinity were calculated from a Scatchard plot. The level of mRNAs was measured by PCR analyses.

RESULTS

Isolation stress enhanced the frequency of the DOI-induced head-twitch response, and yokukansan treatment by feeding significantly reduced this enhancement. Isolation stress significantly increased the 5-HT2A receptor density in the PFC, and yokukansan treatment by feeding as well as administration significantly down-regulated this increase. Isolation stress and yokukansan did not affect the affinity. Among seven constituent herbs, Bupleurum Root, Uncaria Hook, Japanese Angelica Root, and Glycyrrhiza down-regulated the increase, but statistically not significant, in which their efficacies were over 50% relative to yokukansan. Neither isolation stress nor yokukansan affected mRNA levels of 5-HT2A receptors.

CONCLUSION

Yokukansan attenuated drug-induced hallucination-like behaviors in isolated mice, which is suggested to be mediated by 5-HT2A receptor down-regulation in the PFC. This mechanism may underlie the ameliorative effects of yokukansan on hallucination.

Incidence of delirium following total joint replacement in older adults: a meta-analysis

OBJECTIVE

Delirium is common in older adults following total joint replacement (TJR) of the hip and knee. However, reports of the incidence of delirium vary widely, limiting their usefulness. The current meta-analysis therefore examined (1) the incidence of delirium in older patients who underwent TJR and (2) whether these rates vary according to the (a) joint (hip/knee replacement), (b) inclusion/exclusion of patients who underwent simultaneous bilateral surgery, (c) inclusion/exclusion of patients with preexisting cognitive impairments, (d) type of anesthesia (regional/general), (e) method/frequency of assessment, and (f) postoperative interval.

METHOD

Data from 24 studies (2,895 patients) that measured postsurgical delirium following TJR were analyzed. Mean weighted proportions were calculated using a random-effects model to assess the overall incidence of delirium and whether the rate varied according to the aforementioned variables.

RESULTS

Overall, 17% of patients who underwent TJR developed delirium during hospital admission. Individual estimates varied from 0% to 82%, but this variability was not adequately explained by the variables that were examined.

CONCLUSIONS

Delirium is relatively common following TJR; however, it remains unclear why individual estimates vary so widely. Health professionals working with these patients should remain alert to the presentation, diagnosis and management of delirium to optimize postsurgical outcomes.

The protocol of the Oslo Study of Clonidine in Elderly Patients with Delirium; LUCID: a randomised placebo-controlled trial

Background

Delirium affects 15% of hospitalised patients and is linked with poor outcomes, yet few pharmacological treatment options exist. One hypothesis is that delirium may in part result from exaggerated and/or prolonged stress responses. Dexmedetomidine, a parenterally-administered alpha2-adrenergic receptor agonist which attenuates sympathetic nervous system activity, shows promise as treatment in ICU delirium. Clonidine exhibits similar pharmacodynamic properties and can be administered orally. We therefore wish to explore possible effects of clonidine upon the duration and severity of delirium in general medical inpatients.

Methods/Design

The Oslo Study of Clonidine in Elderly Patients with Delirium (LUCID) is a randomised, placebo-controlled, double-blinded, parallel group study with 4-month prospective follow-up. We will recruit 100 older medical inpatients with delirium or subsyndromal delirium in the acute geriatric ward. Participants will be randomised to oral clonidine or placebo until delirium free for 2 days (Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria), or after a maximum of 7 days treatment. Assessment of haemodynamics (blood pressure, heart rate and electrocardiogram) and delirium will be performed daily until discharge or a maximum of 7 days after end of treatment. The primary endpoint is the trajectory of delirium over time (measured by Memorial Delirium Assessment Scale). Secondary endpoints include the duration of delirium, use of rescue medication for delirium, pharmacokinetics and pharmacodynamics of clonidine, cognitive function after 4 months, length of hospital stay and need for institutionalisation.

Discussion

LUCID will explore the efficacy and safety of clonidine for delirium in older medical inpatients.

Trial registration

ClinicalTrials.gov NCT01956604. EudraCT Number: 2013-000815-26

Postoperative plasma copeptin levels independently predict delirium and cognitive dysfunction after coronary artery bypass graft surgery

Copeptin can reflect individual's stress state and are correlated with poor outcome of critical illness. The occurrence of postoperative delirium (POD) and cognitive dysfunction (POCD) is associated with worse outcome after coronary artery bypass graft (CABG) surgery. The present study aimed to investigate the ability of postoperative plasma copeptin level to predict POD and POCD in patients undergoing CABG surgery. Postoperative plasma copeptin levels of 108 patients were measured by an enzyme-linked immunosorbent assay. It was demonstrated that plasma copeptin levels were substantially higher in patients with POD than without POD (1.8±0.6 ng/mL vs. 1.1±0.3 ng/mL; P<0.001) and in patients with POCD than without POCD (1.9±0.6 ng/mL vs. 1.1±0.4 ng/mL; P<0.001). Plasma copeptin level and age were identified as independent predictors for POD [odds ratio (OR), 67.386; 95% confidence interval (CI), 12.031-377.426; P<0.001 and OR, 1.202; 95% CI, 1.075-1.345; P=0.001] and POCD (OR, 28.814; 95% CI, 7.131-116.425; P<0.001 and OR, 1.151; 95% CI, 1.030-1.285; P=0.003) using a multivariate analysis. For prediction of POD, the area under receiver operating characteristic curve (AUC) of the copeptin concentration (AUC, 0.883; 95% CI, 0.807-0.937) was markedly higher than that of age (AUC, 0.746; 95% CI, 0.653-0.825; P=0.020). For prediction of POCD, the AUC of the copeptin concentration (AUC, 0.870; 95% CI, 0.792-0.927) was markedly higher than that of age (AUC, 0.735; 95% CI, 0.641-0.815; P=0.043). Thus, postoperative plasma copeptin level may be a useful, complementary tool to predict POD and POCD in patients undergoing CABG surgery.

Delirium and cognitive decline: more than a coincidence

PURPOSE OF REVIEW

To review the recent findings on the relationships between delirium and cognitive decline in the elderly.

RECENT FINDINGS

Current advances in the field include substantial new evidence that delirium increases the risk of dementia in patients without previous cognitive impairment and accelerates cognitive decline in patients with Alzheimer's disease. Findings on cognitive trajectories and domains affected contribute to better understanding of the clinical nature of cognitive impairment after delirium. Volume loss and disruption of white matter integrity may represent early MRI markers for long-term cognitive impairment. Neurodegenerative and low-level chronic inflammatory processes predispose to exaggerated response to incident stimuli that may precipitate both acute brain dysfunction and persisting cerebral damage.

SUMMARY

Still little is known about the relationship between delirium and cognitive trajectories in the elderly, and the underlying pathophysiological mechanisms. The association of neurodegenerative and inflammatory processes appears to play an important role in the pathogenesis and the clinical course of cognitive impairment after delirium. The hypothetical role of several other factors remains to be clarified. Further clinical studies are needed to evaluate whether prevention and treatment approaches that proved to be useful to reduce delirium incidence and severity may also improve long-term outcomes, and prevent cognitive decline.

The immunology of delirium

Delirium is an acute neuropsychiatric syndrome characterized by acute-onset global cognitive deficits, perceptual and behavioural disturbances affecting mainly elderly subjects with underlying medical or surgical conditions. The pathophysiology of delirium is complex and inflammation is a relevant precipitant factor of this syndrome, although it remains unclear how acute systemic inflammation induces the clinical picture of delirium. The central nervous system is able to detect peripheral infection or tissue destruction through circulating immune mediators and neural ascending signs. Activated microglia is responsible for an acute neuroinflammatory reaction underlying the symptoms of sickness. In healthy conditions descending pathways from the paraventricular nucleus, locus coeruleus and dorsal motor nucleus organize a centralized response to influence the immune response at the periphery and restore homeostasis. In the context of ageing and chronic neurodegeneration, adaptive changes to acute insults are characterized by exaggerated production of pro-inflammatory cytokines by primed microglia coupled with dysfunction of brain-to-immune pathways. In animal models, these changes underlie a more severe manifestation of sickness behaviour with working memory deficits suggesting that inattention, a core feature of delirium, can be a clinical correlate of an increased neuroinflammatory reaction. In patients with delirium, higher levels of pro-inflammatory cytokines and cortisol were identified in plasma and cerebrospinal fluid. However, to date it has not been clarified how peripheral inflammatory or endocrine biomarkers can reflect the likelihood or severity of delirium symptoms. In the future, a better understanding of the interaction between the brain and peripheral organs and the exact mechanism by which systemic inflammation can lead to delirium, will allow the development of new therapeutic agents.

Do stress markers and anesthetic technique predict delirium in the elderly?

BACKGROUND

Postoperative delirium (PD) is a prevalent complication of elderly surgical patients, which predisposes to worsened cognitive recovery and dementia. Risk of PD has been associated with increasing magnitude of the hypothalamic-pituitary-adrenal stress response (serum cortisol, epinephrine and norepinephrine) to surgery. Anesthetics suppress this response; however, some (total intravenous anesthesia, TIVA) more than others (anesthetic gases). Prior comparisons of anesthetics have been equivocal but have not included stress markers. We hypothesized that TIVA would decrease serum stress markers and the incidence of PD.

METHODS

We performed a prospective cohort study of 76 elderly major surgical patients. Patients received TIVA or sevoflurane gas, and blood was drawn for serum markers pre-, intra-, and postoperatively. PD was assessed with the Confusion Assessment Method. We compared stress markers and PD between patients who received TIVA versus sevoflurane, and then modeled PD including stress and anesthetic.

RESULTS

The group that received TIVA during surgery demonstrated lower levels of all stress markers compared to the gas group, but no difference in PD. However, across groups, the postoperative norepinephrine level was much higher in patients who developed PD. Other markers and other times had no effect.

CONCLUSION

The development of PD depends more on postoperative stress than intraoperative stress or anesthetic.