Prevention and treatment options for postoperative delirium in the elderly

Anesthesia, the developing brain, and dexmedetomidine for neuroprotection

Anesthesia-induced neurotoxicity is a set of unfavorable adverse effects on central or peripheral nervous systems associated with administration of anesthesia. Several animal model studies from the early 2000's, from rodents to non-human primates, have shown that general anesthetics cause neuroapoptosis and impairment in neurodevelopment. It has been difficult to translate this evidence to clinical practice. However, some studies suggest lasting behavioral effects in humans due to early anesthesia exposure. Dexmedetomidine is a sedative and analgesic with agonist activities on the alpha-2 (ɑ₂) adrenoceptors as well as imidazoline type 2 (I2) receptors, allowing it to affect intracellular signaling and modulate cellular processes. In addition to being easily delivered, distributed, and eliminated from the body, dexmedetomidine stands out for its ability to offer neuroprotection against apoptosis, ischemia, and inflammation while preserving neuroplasticity, as demonstrated through many animal studies. This property puts dexmedetomidine in the unique position as an anesthetic that may circumvent the neurotoxicity potentially associated with anesthesia.

The Efficacy of Low-Dose Risperidone Treatment for Post-Surgical Delirium in Elderly Orthopedic Patients

Background: Delirium is an acute and typically reversible failure of essential cognitive and attentional functions and is a growing public health concern, with an incidence of 20-50% in patients older than 65 after major surgery and 61% in patients undergoing hip fracture surgery. Numerous treatment strategies have been examined with no conclusive results. The purpose of this study is to assess the efficacy of a three-day low-dose risperidone treatment protocol, 0.5 mg BID, in treating delirium in elderly hospitalized orthopedic surgery department patients. Methods: This study is a prospective non-randomized study involving the senior patient population, older than 65, in an Orthopedic Surgery Department in 2019 and 2020. Delirium was diagnosed by a confusion assessment method (CAM) questionnaire. A three-day 0.5 mg risperidone BID treatment protocol was initiated following diagnosis. Patient data collected included age, gender, chronic diseases, type of surgery and anesthesia and delirium characteristics. Results: The delirium study group included 47 patients with an average age of 84.4 years (±8.6), of whom 53.2% were females. Delirium incidence was 3.7% in all patients older than 65 (1759 patients) and 9.3% in the proximal femoral fracture group. We did not correlate electrolyte imbalance, anemia, polypharmacy and chronic diseases to delirium onset characteristics. Following the three-day low-dose risperidone treatment protocol, 0.5 mg BID, 14.9% of the patients showed CAM score normalization after one day of treatment, and 93.6% within two days. Conclusions: We found our rigid three-day low-dose risperidone treatment protocol, 0.5 mg BID, efficacious in fast delirium resolution, without side effects.

Potential Value of Serum Uric Acid in the Identification of Postoperative Delirium in Geriatric Patients Undergoing Knee Replacement

Objectives

The relationship between preoperative serum uric acid (SUA) and cerebrospinal fluid (CSF) Alzheimer-related biomarkers were investigated to determine whether high SUA is a potential risk factor for postoperative delirium (POD) and to evaluate its predictive efficacy.

Methods

The participants were selected from the Perioperative Neurocognitive Disorder Risk Factor and Prognosis (PNDRFAP) study and the Perioperative Neurocognitive Disorder and Biomarker Lifestyle (PNDABLE) study. The logistic regression equation was used to analyze the risk factors and protective factors of POD. The interaction term (SUA × Sex) was introduced into the linear model to explore the potential modification effects of sex on the identified correlations. We analyzed the mediating effects of Alzheimer-related biomarkers. Finally, we constructed the receiver operating characteristic (ROC) curve and the nomogram model to evaluate the efficacy of SUA and Alzheimer-related biomarkers in predicting POD.

Results

Patients with POD had elevated SUA level (PNDRFAP: p = 0.002, PNDABLE: p < 0.001). Preoperative SUA level was positively correlated with CSF phosphorylated tau (P-tau) (p = 0.027) and β-amyloid42 (Aβ₄₂)/P-tau (p = 0.023). Interaction analysis did not find any modification effect of sex. The relationship between SUA and POD was partially mediated by CSF P-tau (15.3%). ROC curve showed that the model combining SUA and Alzheimer-related biomarkers had better performance in predicting POD [area under the curve (AUC) = 0.880; p < 0.001], and the predictive model is accurate.

Conclusions

High SUA may enhance CSF P-tau level, thus increasing the risk of POD, and the model combining SUA and Alzheimer-related biomarkers can accurately predict the occurrence of POD.

Association between delirium and cognitive impairment: there is a link?

BACKGROUND

Delirium and dementia are both disorders involving global cognitive impairment that can occur separately or at the same time in the elderly.

OBJECTIVE

The aim of this study was to examine the frequency, correlation and relative risk between delirium and cognitive impairment in a prospective population study starting at basal line (onset of delirium) over a period of five years. The secondary aim was to determine any possible correlation between the kind of delirium and a specific type of dementia.

MATERIAL AND METHODS

We studied 325 patients, diagnosed according to the DSM-IV. The neuropsychological, moods and delirium disorders were evaluated with Hamilton Depression Rating Scale, Delirium Rating Scale-Revised-98, MMSE, Rey auditory-verbal learning test, Digit Span, Symbol Digit Modalities Test, Raven Progressive Matrices, ADL and IADL.

RESULTS

The prevalence of delirium in our population was 89 cases (27.4%): 78 patients (48 women and 30 men) showed evolution toward dementia (mean age was 67.9 ± 6.1 years for men and 68.4 ± 9.1 for women), and 11 patients (5 men and 6 women) presented only isolated delirium without evolution toward cognitive impairment (mean age of men was 68.1 ± 5.1 years and of women 66.4 ± 7.1). The neuropsychological study of the patients with delirium with dementia evolution revealed statistically significant differences over time with statistically significant intergroup difference and predisposition toward depression.

CONCLUSION

The association between delirium and cognitive impairment and the possible role of delirium as an early marker of neurodegenerative diseases need to be future investigated.

Related Factors and Treatment of Postoperative Delirium in Old Adult Patients: An Integrative Review

“Postoperative delirium” is defined as delirium occurring in the hospital up to one week after a procedure or before discharge (whichever occurs first) that meets the DSM-5 diagnostic criteria. Objectives: To describe the risk factors related to this pathology and identify effective non-pharmacological forms of treatment. An integrative review of the available literature was performed. The search results considered included all quantitative studies published between 2011 and 2019 in both English and Spanish. A total of 117 studies were selected. Advanced age was identified as the principal risk factor for postoperative delirium. Nursing interventions appear to be the key to preventing or reducing the seriousness of delirium after an anaesthetic episode. The aetiology of postoperative delirium remains unknown, and no treatment exists to eliminate this pathology. The role of nursing staff is fundamental in the prevention, diagnosis, and management of the pathology.

Does cognitive decline/dementia increase Delirium risk after stroke?

BACKGROUND

Delirium is a common contributor to mortality and hospital costs in stroke patients. Different observational studies have showed inconsistent results regarding the association between cognitive decline/dementia and delirium after acute stroke. Therefore, we performed this meta-analysis with the aim of determining whether cognitive decline/dementia is related to the risk of delirium after acute stroke.

METHODS

We systematically searched PubMed, Embase, Google Scholar, and Web of Science for relevant studies from inception to September 2020. We calculated the pooled odds ratio (OR) with 95% confidence interval (CI) by using fixed or random effects models based on heterogeneity measured by the I² index.

RESULTS

The association between cognitive decline/dementia and post-stroke delirium was examined in 13 studies with 3183 participants. After pooled analysis, we found that cognitive decline/dementia was significantly associated with susceptibility to delirium in post-stroke patients (OR = 3.70, 95%CI: 2.90-4.71, P < 0.001). Subgroup analysis suggested that cognitive decline/dementia was associated with an increased risk of delirium in Caucasians (OR = 3.73, 95%CI: 2.73-5.11, P < 0.001), non-Caucasians (OR = 3.65, 95%CI: 2.50-5.33, P < 0.001), samples with <200 subjects (OR = 3.70, 95%CI: 2.17-6.31, P < 0.001), samples with ≥200 subjects (OR = 3.70, 95%CI: 2.82-4.85, P < 0.001), studies published in 1990-2009 (OR = 3.17, 95%CI: 1.48-6.77, P = 0.003), and studies published in 2010-2020 (OR = 3.76, 95%CI: 2.92-4.86, P < 0.001).

CONCLUSIONS

We identified an association between cognitive decline/dementia and the risk of developing delirium. Cognitive decline/dementia may be a promising predictor for delirium in post-stroke patients.

Delirium risk prediction models for intensive care unit patients: A systematic review

OBJECTIVE

To systematically review the delirium risk prediction models for intensive care unit (ICU) patients.

METHODS

A systematic review was conducted. The Cochrane Library, PubMed, Ovid and Web of Science were searched to collect studies on delirium risk prediction models for ICU patients from database establishment to 31 March 2019. Two reviewers independently screened the literature according to the pre-determined inclusion and exclusion criteria, extracted the data and evaluated the risk of bias of the included studies using the CHARMS (CHecklist for critical Appraisal and data extraction for systematic Reviews of prediction Modelling Studies) checklist. A descriptive analysis was used to describe and summarise the data.

RESULTS

A total of six models were included. All studies reported the area under the receiver operating characteristic curve (AUROC) of the prediction models in the derivation and (or) validation datasets as over 0.7 (from 0.75 to 0.9). Five models reported calibration metrics. Decreased cognitive reserve and the Acute Physiology and Chronic Health Evaluation II (APACHE-II) score were the most commonly reported predisposing and precipitating factors, respectively, of ICU delirium among all models. The small sample size, lack of external validation and the absence of or unreported blinding method increased the risk of bias.

CONCLUSION

According to the discrimination and calibration statistics reported in the original studies, six prediction models may have moderate power in predicting ICU delirium. However, this finding should be interpreted with caution due to the risk of bias in the included studies. More clinical studies should be carried out to validate whether these tools have satisfactory predictive performance in delirium risk prediction for ICU patients.

Development and validation of a dynamic delirium prediction rule in patients admitted to the Intensive Care Units (DYNAMIC-ICU): A prospective cohort study

BACKGROUND

Delirium is one of the most common cognitive complications among patients admitted to the intensive care units (ICU).

OBJECTIVE

To develop and validate a DYNAmic deliriuM predICtion rule for ICU patients (DYNAMIC-ICU) and to stratify patients into different risk levels among patients in various types of ICUs.

DESIGN

Prospective cohort study.

SETTING AND PARTICIPANTS

A total of 560 (median age of 66 years, 62.5% male) consecutively enrolled patients from four ICUs were included in the study. The patients were randomly assigned into either the derivation (n = 336, 60%) or the validation (n = 224, 40%) cohort by stratified randomization based on delirium/non-delirium and types of ICU.

METHODS

The simplified Chinese version of the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) was used to assess delirium until patients were discharged from the ICUs. Potential predisposing, disease-related, and iatrogenic and environmental risk factors as well as data on patients' outcomes were collected prospectively.

RESULTS

Of the enrolled patients, 20.2% and 20.5% developed delirium in the derivation and validation cohorts, respectively. Predisposing factors (history of chronic diseases, hearing deficits), disease-related factors (infection, higher APACHE II scores at admission), and iatrogenic and environmental factors (the use of sedatives and analgesics, indwelling catheter, and sleep disturbance) were identified as independent predictors of delirium. Points were assigned to each predictor according to their odds ratio to create a prediction rule which was internally validated based on total scores and by bootstrapping (AUCs of 0.907 [95% CI 0. 871 -0.944], 0.888 [95% CI 0.845-0.932], and 0.874 [95% CI 0.828-0.920]), respectively. The total score of the DYNAMIC-ICU ranged from 0 to 33 and patients were divided into low risk (0-9), moderate risk (10-17), high risk (18-33) groups in developing delirium according to their total score with incidence of delirium at 2.8%, 16.8% and 75.9% in the derivation group, respectively. The DYNAMIC-ICU and its performance of risk level stratification were further validated in the validation cohort (AUC = 0.900 [95% CI 0.858-0.941]). The all-cause mortality was increased and the length of hospital stay was prolonged dramatically with the increase of delirium risk levels in both derivation (p = 0.034, p < 0.001) and validation cohorts (p < 0.001, p < 0.001).

CONCLUSIONS

Seven predictors for ICU delirium were identified to create DYNAMIC-ICU, which could well stratify ICU patients into three different delirium risk levels, tailor risk level changes, and predict in-hospital outcomes by a dynamic assessment approach.

Incidence and risk factors for delirium development in ICU patients - a prospective observational study

BACKGROUND AND AIMS

Delirium is an acute brain dysfunction and a frequent complication in critically ill patients. When present it significantly worsens the prognosis of patients. The aim of this study was to evaluate the incidence of delirium and risk factors for delirium in a mixed group of trauma, medical and surgical ICU patients.

METHODS

A prospective observational study was conducted in one of the six-bed Intensive Care Units of the University Hospital Ostrava in the Czech Republic during a 12-month period. We evaluated the incidence of delirium and its predisposing and precipitating risk factors. All patients were assessed daily using the Confusion Assessment Method for the ICU (CAM-ICU).

RESULTS AND CONCLUSIONS

Of the total of 332 patients with a median APACHE II (the Acute Physiology and Chronic Health Evaluation) score of 12, who were evaluated for delirium, 48 could not be assessed using CAM-ICU (47 due to prolonged coma, 1 due to language barriers). The incidence of delirium was 26.1%, with trauma and medical patients being more likely to develop delirium than surgical patients. Risk of delirium was significantly associated with age ≥ 65 years, and alcohol abuse in their anamnesis, with APACHE II score on admission, and with the use of sedatives and/or vasopressors. Delirious patients who remained in the ICU for a prolonged period showed a greater need for ventilator support and had a greater ICU-mortality.

Delirium in the elderly: Current problems with increasing geriatric age

Delirium is an acute disorder of attention and cognition seen relatively commonly in people aged 65 yr or older. The prevalence is estimated to be between 11 and 42 per cent for elderly patients on medical wards. The prevalence is also high in nursing homes and long term care (LTC) facilities. The consequences of delirium could be significant such as an increase in mortality in the hospital, long-term cognitive decline, loss of autonomy and increased risk to be institutionalized. Despite being a common condition, it remains under-recognised, poorly understood and not adequately managed. Advanced age and dementia are the most important risk factors. Pain, dehydration, infections, stroke and metabolic disturbances, and surgery are the most common triggering factors. Delirium is preventable in a large proportion of cases and therefore, it is also important from a public health perspective for interventions to reduce further complications and the substantial costs associated with these. Since the aetiology is, in most cases, multfactorial, it is important to consider a multi-component approach to management, both pharmacological and non-pharmacological. Detection and treatment of triggering causes must have high priority in case of delirium. The aim of this review is to highlight the importance of delirium in the elderly population, given the increasing numbers of ageing people as well as increasing geriatric age.

Pre-surgical Geriatric Syndromes, Frailty, and Risks for Postoperative Delirium in Older Patients Undergoing Gastrointestinal Surgery: Prevalence and Red Flags

OBJECTIVE

We sought to identify and evaluate red flags for pre-surgical geriatric conditions (geriatric syndromes, frailty, and risks for postoperative delirium) in older patients undergoing gastrointestinal surgery.

METHODS

Older individuals (≥65 years) undergoing major elective gastrointestinal surgery from 2009 to 2012 were enrolled and assessed preoperatively.

RESULTS

Participants (N=379; mean age=74.5 ± 5.9 years) primarily underwent colorectal (54.3 %), gastric (21.9 %), and pancreatobiliary (12.6 %) surgery. Overall, 30.9 % had existing geriatric syndromes, 26.7 % were frail, and 22.8 % had >3 risk factors for postoperative delirium. The largest proportion (45.7 %) presented with at least one geriatric condition. Patients with or without geriatric conditions were discriminated with adequate sensitivity (67 %), specificity (84 %), and positive predictive value (77 %) by eight red flags: age ≥75 years (OR, 2.86; P<0.001), eating soft food (OR, 3.63; P=0.001), reported hypertension (OR, 2.8; P=0.001), weight loss >3 kg (OR, 4.79; P<0.001), fair-to-weak grip strength (OR, 2.53; P=0.001), sleeplessness (OR, 2.57; P=0.001), no-better-than-peer perceived health (OR, 1.88; P=0.022), and short-term inability to recall two of three common words (OR, 1.81; P=0.025).

CONCLUSIONS

Eight red flags covered as part of history and physical examination are well suited to screen patients for geriatric conditions indicating the need for preoperative geriatric assessments and optimization.

Hepatectomy in elderly patients: does age matter?

BACKGROUND

With the increase in average life expectancy in recent decades, the proportion of elderly patients requiring liver surgery is rising. The aim of the meta-analysis reported here was to evaluate the safety and efficacy of hepatectomy in elderly patients.

METHODS

An extensive electronic search was performed for relevant articles that compare the outcomes of hepatectomy in patients ≥70 years of age with those in younger patients prior to October 2012. Analysis of pooled data was performed with RevMan 5.0.

RESULTS

Twenty-eight observational studies involving 15,480 patients were included in the analysis. Compared with the younger patients, elderly patients experienced more complications (31.8 vs 28.7 %; P = 0.002), mainly as a result of increased cardiac complications (7.5 vs 1.9 %; P < 0.001) and delirium (11.7 vs 4.5 %; P < 0.001). Postoperative major surgical complications (12.6 vs 11.3 %; P = 0.55) and mortality (3.6 vs 3.3 %; P = 0.68) were comparable between elderly and younger patients. For patients with malignancies, both the 5-year disease-free survival (26.5 vs 26.3 %; P = 0.60) and overall survival (39.5 vs 40.7 %; P = 0.29) did not differ significantly between the two groups.

CONCLUSIONS

Postoperative major surgical complications, mortality, and long-term results in elderly patients seem to be comparable with those in younger patients, suggesting that age alone should not be considered a contraindication for hepatectomy.

Do antipsychotics prevent postoperative delirium? A systematic review and meta-analysis

OBJECTIVE

To summarize the effect of antipsychotics for preventing postoperative delirium.

DESIGN

We conducted a literature search using Medline, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews and clinicaltrials.gov. We included randomized controlled trials of adults undergoing surgery who were given antipsychotics to prevent postoperative delirium. Quality was assessed via the Cochrane risk of bias tool. Random-effects meta-analysis and meta-regression were conducted. Q-statistics and I(2) were used for assessment of heterogeneity. The main outcome was delirium incidence using validated definitions.

RESULTS

A total of 1710 subjects were included, with a mean age ranging from 60.7 to 86.4 years. Antipsychotics reduced the incidence of postoperative delirium with the global effect-size estimate (weighted odds ratio) using the random effects model of 0.44 (95% confidence interval: 0.28-0.70; N = 6; Q-value: 16, p-value 0.0005; I(2) = 69%). Significant heterogeneity existed with the pooled global effect of delirium incidence; however, meta-regression allowed us to test both treatment-level and patient-level explanations for significant between-study variance. Baseline risk for delirium was found to be a significant contributor to study heterogeneity, and meta-regression suggested that antipsychotic type and dosage were two of the several treatment-level factors that also may have led to heterogeneity. Our analysis implied the presence of a breakeven baseline level of delirium risk below which preventive treatment with antipsychotics might prove ineffective.

CONCLUSIONS

Within the limits of few randomized controlled trials, antipsychotics appeared to reduce the incidence of postoperative delirium in several surgical settings, predominantly orthopedic and for those at higher risk for delirium.

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.

Intravenous Patient-controlled Analgesia Has a Positive Effect on the Prognosis of Delirium in Patients Undergoing Orthopedic Surgery

BACKGROUND

Postoperative delirium is relatively common. However, the relationship between intravenous patient-controlled analgesia (IV-PCA) and delirium has not been thoroughly investigated. The aim of this study was to evaluate the effects of IV-PCA on the prognosis of postoperative delirium in patients undergoing orthopedic surgery.

METHODS

Medical records of 129 patients with postoperative delirium were reviewed. Patients were divided into two groups according to whether they used IV-PCA with fentanyl and ketorolac. The IV-PCA group consisted of 73 patients who were managed with IV-PCA; the NO-PCA group consisted of 56 patients who were managed without PCA.

RESULTS

Incidences of multiple psychiatric consultations and prolonged delirium were significantly lower in patients using IV-PCA with fentanyl and ketorolac than in those without PCA.

CONCLUSIONS

We recommend the use of IV-PCA for pain control and management of delirium in patients with postoperative delirium.

Strategies for prevention of postoperative delirium: a systematic review and meta-analysis of randomized trials

INTRODUCTION

The ideal measures to prevent postoperative delirium remain unestablished. We conducted this systematic review and meta-analysis to clarify the significance of potential interventions.

METHODS

The PRISMA statement guidelines were followed. Two researchers searched MEDLINE, EMBASE, CINAHL and the Cochrane Library for articles published in English before August 2012. Additional sources included reference lists from reviews and related articles from 'Google Scholar'. Randomized clinical trials (RCTs) on interventions seeking to prevent postoperative delirium in adult patients were included. Data extraction and methodological quality assessment were performed using predefined data fields and scoring system. Meta-analysis was accomplished for studies that used similar strategies. The primary outcome measure was the incidence of postoperative delirium. We further tested whether interventions effective in preventing postoperative delirium shortened the length of hospital stay.

RESULTS

We identified 38 RCTs with interventions ranging from perioperative managements to pharmacological, psychological or multicomponent interventions. Meta-analysis showed dexmedetomidine sedation was associated with less delirium compared to sedation produced by other drugs (two RCTs with 415 patients, pooled risk ratio (RR)=0.39; 95% confidence interval (CI)=0.16 to 0.95). Both typical (three RCTs with 965 patients, RR=0.71; 95% CI=0.54 to 0.93) and atypical antipsychotics (three RCTs with 627 patients, RR=0.36; 95% CI=0.26 to 0.50) decreased delirium occurrence when compared to placebos. Multicomponent interventions (two RCTs with 325 patients, RR=0.71; 95% CI=0.58 to 0.86) were effective in preventing delirium. No difference in the incidences of delirium was found between: neuraxial and general anesthesia (four RCTs with 511 patients, RR=0.99; 95% CI=0.65 to 1.50); epidural and intravenous analgesia (three RCTs with 167 patients, RR=0.93; 95% CI=0.61 to 1.43) or acetylcholinesterase inhibitors and placebo (four RCTs with 242 patients, RR=0.95; 95% CI=0.63 to 1.44). Effective prevention of postoperative delirium did not shorten the length of hospital stay (10 RCTs with 1,636 patients, pooled SMD (standard mean difference)=-0.06; 95% CI=-0.16 to 0.04).

CONCLUSIONS

The included studies showed great inconsistencies in definition, incidence, severity and duration of postoperative delirium. Meta-analysis supported dexmedetomidine sedation, multicomponent interventions and antipsychotics were useful in preventing postoperative delirium.