Prevalence and Risk Factors for Postoperative Delirium in a Cardiovascular Intensive Care Unit

Relationship Between Delirium Development and Its Causative Factors in the Intensive Care Unit After Cardiac Surgery

Background

Delirium is a clinical symptom that can have serious side effects in patients, and it develops acutely and shows reversibility. Postoperative delirium is an important neuropsychological complication after surgery that directly or indirectly affects patients.

Cardiac surgery increases the risk of delirium due to the complexity of surgical procedures, use of intraoperative and postoperative anesthetics and other pharmacologic agents, and possible postoperative complications. This study aims to determine the relationship between the development of delirium and its causative factors after cardiac surgery and its associated postoperative complications, and identify the high-relevance risk factors of postoperative delirium.

Methods

The participants comprised 730 patients who were admitted to the intensive care unit and underwent cardiac surgery. The collected data included 19 risk factors based on the patients' medical information records. As a delirium diagnostic tool, we used the Intensive Care Delirium Screening Checklist, with four or more points indicating delirium. For statistical analysis, the dependent variables were determined based on the presence or absence of delirium, while the independent variables were determined based on the risk factors of delirium. A t-test, χ² test, and logistic regression analysis were performed on risk factors between the two groups-the delirium group and no delirium group.

Results

Postoperative delirium was observed in 126 (17.3%) of 730 patients after cardiac surgery. Postoperative complications were more common in the delirium group. Independent risk factors associated with postoperative delirium were identified in 7 of the 12 factors.

Conclusion

As cardiac surgery is invasive and affects the development and severity of delirium, efforts and intervention methods are necessary to predict the risk factors for the development of delirium before surgery, and to prevent its occurrence after surgery. In the future, it is necessary to further investigate factors associated with delirium that can be directly intervened.

Association between obstructive sleep apnea and atrial fibrillation and delirium after cardiac surgery. Sub-analysis of DECADE trial

BACKGROUND

Atrial fibrillation and delirium are common complications after cardiac surgery. Both are associated with increased Intensive Care Unit (ICU) and hospital length of stay, functional decline, 30-day mortality and increase in health care costs. Obstructive Sleep Apnea (OSA) induces deleterious effects in the cardiovascular and nervous systems. We hypothesized that adult patients with preoperative OSA have a higher incidence of postoperative atrial fibrillation and delirium than patients without OSA, after cardiac surgery.

METHODS

Sub-analysis of the DECADE trial at Cleveland Clinic hospitals. Our exposure was OSA, defined by STOP-BANG questionnaire score higher than 5 and/or a preoperative diagnosis of OSA. The primary outcome was atrial fibrillation, defined by clinician diagnosis or documented arrhythmia. The secondary outcome was delirium assessed twice during the initial five postoperative days using the Confusion Assessment Method for ICU. We assessed the association between OSA, and atrial fibrillation and delirium using a logistic regression model adjusted for confounders using inverse probability of treatment weighting.

RESULTS

590 patients were included in the final analysis. 133 were diagnosed with OSA and 457 had no OSA. Satisfactory balance between groups for most confounders (absolute standardized difference < 0.10) was achieved after weighting. The atrial fibrillation incidence was 37% (n = 49) in the patients with OSA and 33% (n = 150) in the non-OSA patients. OSA was not associated with atrial fibrillation with an estimated odds ratio of 1.22 (95% CI: 0.75,1.99;p = 0.416). The delirium incidence was 17% (n = 22) in patients with OSA and 15% (n = 67) in the non-OSA patients. OSA was not associated with delirium with an estimated odds ratio of 0.93 (95% CI: 0.51,1.69;p = 0.800).

CONCLUSION

In adult patients having cardiac surgery, OSA is not associated with a higher incidence of postoperative atrial fibrillation and delirium. These results suggest different prominent factors rather than OSA affect the incidence of these postoperative outcomes.

Associations of albumin and nutritional index factors with delirium in patients admitted to the cardiac intensive care unit

Background

Limited data are available on the association of malnutrition with the occurrence of delirium in the cardiac intensive care unit (CICU). Thus, we aimed to analyze whether nutritional indices and their components can predict the development of delirium in CICU.

Methods

We enrolled 2,783 patients admitted to the CICU of Samsung Medical Center for more than 24 h between September 2012 and December 2018. We assessed the nutritional status at admission using three indices, the Prognostic Nutrition Index (PNI), the Geriatric Nutritional Risk Index (GNRI), and the Controlling Nutritional Status (CONUT). Then, we compared predictive performances for the occurrence of delirium among nutritional indices using Delong's test.

Results

Delirium developed in 678 patients (24.3%) assessed three times daily for 7 days of CICU stay. Nutritional indices had fair predictive performance for development of delirium in critically ill cardiac patients using the area under the receiver-operating characteristic curve (AUROC: 0.729 for the GNRI, 0.728 for PNI, and 0.762 for CONUT). Furthermore, the AUROC of albumin alone (0.77, 95% CI, 0.75-0.79) was significantly greater than that of either GNRI (p < 0.001) or PNI (p < 0.001). In a multivariable analysis including each component of nutritional indices, albumin was a significant predictor for delirium but not absolute lymphocyte count, bodyweight/ideal bodyweight, or total cholesterol level as a component of nutritional indices.

Conclusion

Predictive performances of nutritional indices for the occurrence of delirium were acceptable in patients admitted to CICU. Albumin alone might be a helpful and straightforward indicator for the occurrence of delirium.

Self-efficacy of caring for patients in the intensive care unit with delirium: Development and validation of a scale for intensive care unit nurses

BACKGROUND

Improving the self-efficacy of intensive care unit nurses for delirium care could help them adapt to the changing situation of delirium patients. Validated measures of nurses' self-efficacy of delirium care are lacking OBJECTIVES: The objective of this study was to develop a Delirium Care Self-Efficacy Scale for assessing nurses' confidence about caring for patients in the intensive care unit and to examine the scale's psychometric properties.

METHODS

Draft scale items were generated from a review of relevant literature and face-to-face interviews with intensive care unit nurses; content validity was conducted with a panel of five experts in delirium. A group of nurses were recruited by convenience sampling from intensive care units (N = 299) for item analysis of the questionnaire, assessment of validity, and reliability of the scale. Nurse participants were recruited from nine adult critical care units affiliated with a hospital in Taiwan. Data were collected from August 2020 to July 2021.

RESULTS

Content validity index was 0.98 for the initial 26 items, indicating good validity. The critical ratio for item discrimination was 14.47-19.29, and item-to-total correlations ranged from 0.67 to 0.81. Principal component analysis reduced items to 13 and extracted two factors, confidence in delirium assessment and confidence in delirium management, which explained 66.82% of the total variance. Cronbach's alpha for internal consistency was 0.94 with good test-retest reliability (r = 0.92). High scale scores among participants were significantly associated with age (≥40 years), work experience in an intensive care unit (≥10 years), delirium education, and willingness to use delirium assessment tools.

CONCLUSIONS

The newly developed Delirium Care Self-Efficacy Scale demonstrated acceptable reliability and validity as a measure of confidence for intensive care nurses caring for and managing patients with delirium in the intensive care unit.

What is the impact of perioperative cerebral oxygen desaturation on postoperative delirium in old population: a systemic review and meta-analysis

BACKGROUND

Perioperative cerebral oxygen saturation (ScO₂) has been reported to associate with postoperative delirium (POD) which is a common postoperative complication, however, the results were inconclusive. Therefore, we aimed to conduct an up-to-date review and meta-analyze the relationship between perioperative ScO₂ and POD.

METHODS

We systematically searched PubMed, Embase and Web of science through January 13, 2022. The pooled results were estimated through a random-effects model meta-analysis and expressed as odds ratios (ORs) and standard mean differences (SMDs), accompanied with 95% confident intervals (CIs).

RESULTS

Finally, of 467 searched articles, ten articles were included. A total of six studies reported the baseline ScO₂ value and the pooled result showed that preoperative baseline ScO₂ was lower in POD groups (SMD = - 0.41, 95% CI - 0.64 to - 0.18). And beyond that, the pooled OR across four literatures about preoperative low ScO₂ on POD was 3.44 (95% CI 1.69, 7.02). In contrast, insignificant differences were detected in baseline/lowest ScO₂ value during intraoperative and postoperative period. Additionally, there were no statistically significant associations for intraoperative and postoperative low ScO₂ effect on POD risk. Meta-regress analysis has found no significant impact factors.

CONCLUSIONS

Based on current evidence, POD patients have a lower ScO₂, and ScO₂ desaturation may increase POD incidence, indicating the role of ScO₂ underlying pathological mechanisms. For generalizability of evidence, we should rely on high-quality, considering more comprehensively longitudinal, interdisciplinary studies.

Relationship between preoperative anxiety and onset of delirium after cardiovascular surgery in elderly patients: focus on personality and coping process

BACKGROUND

Postoperative delirium is associated with increased mortality. Therefore, it is important to manage delirium during the entire perioperative period. Preoperative anxiety is associated with poor prognosis in postoperative patients who have undergone cardiovascular surgery. This study aims to investigate the relationship between preoperative anxiety and onset of delirium after cardiovascular surgery in elderly patients (aged 65 years or older), considering the individual psychological characteristics, such as personality and stress coping skills in response to anxiety, as confounding factors.

METHODS

This prospective study included patients aged >65 years in a preoperative state before undergoing cardiovascular surgery. Subjects were divided into two groups based on whether they experienced postoperative delirium, or not. We compared clinical and demographic factors, preoperative psychiatric and psychological factors, and intraoperative and perioperative physical factors between the control and delirium groups. Multiple imputations were used to account for missing data.

RESULTS

Out of 168 subjects enrolled in this study, 26 (15.5%) developed postoperative delirium. Univariate analysis showed significant differences in age (P = 0.027), cognitive function (P = 0.007), agreeableness (P = 0.029), and the Acute Physiology and Chronic Health Evaluation-II (APACHE-II) score (P = 0.023) between the delirium and control groups. Multiple logistic regression analysis did not identify a significant association between preoperative anxiety and the onset of postoperative delirium. However, age (odds ratio (OR) = 1.114, P = 0.018), agreeableness (OR = 0.555, P = 0.008), and the APACHE-II score (OR = 1.227, P = 0.008) were identified as risk factors for postoperative delirium.

CONCLUSION

Agreeableness, one of the personality traits associated with preoperative anxiety, appears to be involved in the development of postoperative delirium as an independent psychological factor, regardless of age or physical factors.

Albumin/fibrinogen ratio, an independent risk factor for postoperative delirium after total joint arthroplasty

AIM

Postoperative delirium (POD) is a very common and serious complication after total joint arthroplasty (TJA), which is closely associated with many adverse consequences and a poor prognosis. This study aimed to establish the potential risk factors for POD.

METHODS

In total, 336 patients who underwent elective TJA under general anesthesia between 2018 and 2021 were included and deemed eligible for inclusion. POD was diagnosed based on the criteria by the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM V). The receiver operating characteristic curve was drawn to evaluate the predictive and cut-off values of continuous variables for POD. Potential risk factors for POD were evaluated by binary univariate and multivariate analysis with the "Enter" method.

RESULTS

According to the criteria by DSM V, 43 patients were categorized into the POD group, with an incidence of 12.8% (43 of 336). The receiver operating characteristic curve showed that albumin/fibrinogen ratio (AFR) was a good predictor for POD with an area under the curve of 0.754, cut-off value of 9.65, sensitivity of 57.00% and specificity of 83.72% (P <0.001). A low preoperative AFR level (<9.65) was determined as the only independent risk factor for POD by the univariate and multivariate logistic regression analyses (OR: 2.45, 95% CI: 2.01-2.94, P = 0.008).

CONCLUSIONS

Our results indicate that a low AFR is an independent risk factor for POD in elderly subjects after TJA. Geriatr Gerontol Int 2022; 22: 412-417.

Delirium Prevention in Postcardiac Surgical Critical Care

This review provides an overview for health care teams involved in the perioperative care of cardiac surgery patients. The intention is to summarize key determinants of delirium, its impact on short- and long-term outcomes as well as to discuss effective management strategies. The first component of this review examines the prevalence and the factors associated with an increased risk of postoperative delirium. A multitude of predisposing (eg, baseline vulnerability and comorbidities) and precipitating (eg, type of cardiac surgery and postoperative care) factors that contribute to the occurrence of delirium are discussed.

Delirium and depression in cardiac surgery: A comprehensive review of risk factors, pathophysiology, and management

BACKGROUND

Mental health and wellbeing continue to gain more attention as they are inextricably associated with clinical outcomes, particularly quality of life. Many medical ailments and major surgeries affect patients' mental health, including depression and delirium.

AIMS

The objective of this manuscript was to comprehensively review and critically examine the literature pertaining to cardiac surgery, depression, and delirium.

METHODS

This is a narrative review article. We performed our search analysis by using the following key words: "Cardiac Surgery", "Depression", "Delirium", "Clinical outcomes", and "Mental Health". Search analysis was done on MedLine PubMed, accessing indexed peer-reviewed publications.

RESULTS

Cardiac Surgery is a life-altering intervention indicated to improve morbidity and mortality in patients with cardiovascular diseases. Psychiatric conditions before and after cardiac surgery worsen patient prognosis and increase mortality rate. Specifically, preoperative depression increases postoperative depression and is associated with impaired functional status, slow physical recovery, and an increased readmission rate.

DISCUSSION

Although the exact pathophysiology between depression and cardiovascular disease (CVD) is unknown, several pathways have been implicated. Unmanaged depression can also lead to other psychological conditions such as delirium. Like depression, the exact association between delirium and CVD is not well understood, but believed to be multifactorial.

CONCLUSION

Herein, we provide a comprehensive review of the links between depression, delirium, and cardiovascular surgery. We critically examine the current data that pertains to the pathophysiology of these debilitating mental health issues in the context of cardiac surgery. Finally, we summarize the various treatment options available for managing depression and delirium in the cardiac surgery patient population.

A survey about postoperative delirium in older patients among nurses and anaesthetists: implications for future practice and policy

BACKGROUND

Postoperative delirium is a major complication associated with anaesthesia and surgery, more commonly seen in older people.

AIMS

The aims of this study were to explore the knowledge and understanding of anaesthetists and nurses involved in anaesthesia through their responses to two case scenarios of postoperative delirium experienced by older people.

METHODS

A 30-item online survey was sent to 500 potential respondents.

RESULTS

Two hundred and twenty-six practitioners from Australia, New Zealand and Scotland responded. Most had no workplace protocols for anaesthesia planning in older people. There was substantial variability in practice in relation to postoperative delirium screening, detection, prevention and management.

CONCLUSIONS

Improvements in education and awareness, together with a more coherent approach, for example, as recommended in the European Society of Anaesthesiology Guidelines, could help to reduce the impact of postoperative delirium in older people. This should be combined with ongoing research into perioperative optimisation of detection, prevention and management of postoperative delirium.

Diagnosis, prevention, and management of delirium in the intensive cardiac care unit

Delirium is a frequent complication in patients admitted to intensive cardiac care units (ICCU) with potentially severe consequences including increased risks of mortality, cognitive impairment and dependence at discharge, and longer times on mechanical ventilation and hospital stay. Delirium has been widely documented and studied in general intensive care units and in patients after cardiac surgery, but it has barely been studied in acute nonsurgical cardiac patients. Moreover, delirium (especially in its hypoactive form) is commonly misdiagnosed. We propose a protocol for delirium prevention and management in ICCUs. A daily comprehensive assessment to improve detection should be done using validated scales (ie, confusion assessment method). Preventive measures are particularly relevance and constitute the basis of treatment as well, acting on reversible risk factors, including environmental interventions, such as quiet time, sleep promotion, family support, communication, and adequate treatment of pain and dyspnea. Pharmacological prophylaxis is not indicated with the exception of patients at risk of withdrawal syndrome but should only be used in patients with confirmed delirium. Dexmedetomidine is the drug of choice in patients with severe agitation, and those weaning from invasive mechanical ventilation. As the complexity of ICCUs increases, clinical scenarios posing challenges for the management of delirium become more frequent. Efforts should be done to improve the identification of patients at risk during admission in order to establish preventive interventions to avoid this complication. Patient-centered protocols will increase the awareness of the healthcare professionals for better prevention and earlier diagnosis and will positively impact on prognosis.

Dexmedetomidine in Adult Patients in Cardiac Surgery Critical Care: An Evidence-Based Review

Although several options are available for postoperative sedation in the intensive care unit, the selective α2-adrenoceptor agonist dexmedetomidine may offer advantages for patients after cardiac surgery. The author conducted a review of the literature on the use of dexmedetomidine in the cardiac surgery population to determine possible advantages and disadvantages in this patient population. Although the use of dexmedetomidine has not been conclusively shown to change overall morbidity and mortality and may be associated with higher drug cost, its other demonstrated effects offer advantages for postoperative cardiac surgery patients that other forms of sedation cannot match.

Preoperative C-Reactive Protein/Albumin Ratio, a Risk Factor for Postoperative Delirium in Elderly Patients After Total Joint Arthroplasty

BACKGROUND

Postoperative delirium (POD), as an acute brain failure, is widely reported as a very common postoperative complication, and it is closely associated with increased morbidity and mortality. This study aimed to investigate potential risk factors including C-reactive protein/albumin ratio (CAR) for POD in elderly subjects after total joint arthroplasty (TJA).

METHODS

A total of 272 elderly patients (aged 65∼85 years) who were scheduled to undergo elective TJA with epidural anesthesia were consecutively recruited. The data of baseline characteristics, operation-associated indexes, and preoperative laboratory tests were collected. POD assessment was performed daily within postoperative 7 days. Receiver operating characteristic curve analysis was utilized for evaluating the predictive and cut-off value of CAR for POD. Risk factors for POD were evaluated by the binary univariate and multivariate logistic regression analyses.

RESULTS

Within postoperative 7 days, there were 55 patients who had suffered POD with an incidence of 20.2% (55/272). The area under the curve of CAR for POD was 0.804, with the cut-off value of 2.35, a sensitivity of 66.82%, and a specificity of 80.00%, respectively (95% confidence interval [CI]: 0.737-0.872, P < .001). Age (odds ratio: 2.02, 95% CI: 1.03-3.96, P = .038) and preoperative CAR level (odds ratio: 3.04, 95% CI: 1.23-7.23, P = .016) were 2 independent risk factors for POD in elderly subjects undergoing TJA.

CONCLUSIONS

Preoperative CAR level may be a promising predictor for POD in elderly subjects following TJA.

Diagnostic Performance and Utility of Quantitative EEG Analyses in Delirium: Confirmatory Results From a Large Retrospective Case-Control Study

Background. The lack of objective disease markers is a major cause of misdiagnosis and nonstandardized approaches in delirium. Recent studies conducted in well-selected patients and confined study environments suggest that quantitative electroencephalography (qEEG) can provide such markers. We hypothesize that qEEG helps remedy diagnostic uncertainty not only in well-defined study cohorts but also in a heterogeneous hospital population. Methods. In this retrospective case-control study, EEG power spectra of delirious patients and age-/gender-matched controls (n = 31 and n = 345, respectively) were fitted in a linear model to test their performance as binary classifiers. We subsequently evaluated the diagnostic performance of the best classifiers in control samples with normal EEGs (n = 534) and real-world samples including pathologic findings (n = 4294). Test reliability was estimated through split-half analyses. Results. We found that the combination of spectral power at F3-P4 at 2 Hz (area under the curve [AUC] = .994) and C3-O1 at 19 Hz (AUC = .993) provided a sensitivity of 100% and a specificity of 99% to identify delirious patients among normal controls. These classifiers also yielded a false positive rate as low as 5% and increased the pretest probability of being delirious by 57% in an unselected real-world sample. Split-half reliabilities were .98 and .99, respectively. Conclusion. This retrospective study yielded preliminary evidence that qEEG provides excellent diagnostic performance to identify delirious patients even outside confined study environments. It furthermore revealed reduced beta power as a novel specific finding in delirium and that a normal EEG excludes delirium. Prospective studies including parameters of pretest probability and delirium severity are required to elaborate on these promising findings.

Predictive factors for effectiveness and safety of enoxaparin for total knee arthroplasty in aged Japanese patients: a retrospective review

BACKGROUND

The aims of this study were to investigate predictive factors involved in effectiveness and safety of enoxaparin for prevention of postoperative venous thromboembolism in aged Japanese total knee arthroplasty (TKA) patients.

METHODS

Japanese patients over 65 years old who were administered enoxaparin for TKA were enrolled in this study. Their medical records were retrospectively reviewed. Data were corrected at the Izumi Regional Medical Center, from September 2009 to March 2014. Patients were stratified into groups according to whether enoxaparin was effective (no deep vein thrombosis event up to postoperative day 7) or not, and whether they had an adverse drug event (ADE) or not.

RESULTS

A total of 128 patients were included in this study. One hundred five (82.0%) patients were in the effective group and 20 (15.6%) in the adverse drug event (ADE) group. Anemia (13 patients), abnormalities in liver function tests (4 patients), clinically relevant non-major bleeding (4 patients) and urticaria (1 patient) were observed as ADEs. Multivariate logistic regression analysis showed that the serum total protein level at postoperative day 1 (POD1, before enoxaparin administration), was associated with effectiveness of enoxaparin, while the serum total protein and hemoglobin level at POD1 were involved in ADE caused by enoxaparin.

CONCLUSIONS

Although further large scale studies will be warranted, our results suggest that serum total protein level just before enoxaparin treatment for TKA relates to the effectiveness and safety of enoxaparin in a Japanese aged population. In addition, the results indicate that the development of anemia should be carefully monitored during enoxaparin treatment for TKA, particularly in patients with lower levels of serum hemoglobin before treatment.

Early illness experiences related to unexpected heart surgery: A qualitative descriptive study

BACKGROUND

Most studies on patients' experiences following emergency cardiac surgery focus on evaluation of patients after their discharge. Few studies have evaluated patients' experiences after being transferred from intensive care and before being discharged.

OBJECTIVE

This study aimed to describe patients' experiences in the early stages of recovery following emergency heart surgery.

METHODS

For this exploratory qualitative descriptive study, 13 patients were recruited from a medical centre in northern Taiwan. Participants had undergone emergency heart surgery and had resided in the cardiothoracic surgical ward for ≥6 days following transfer from the ICU; all expected to be discharged from the hospital within 3 days. Semi-structured, face-to-face interviews were conducted in private after the patients had been transferred to the cardiothoracic surgical wards. Audiotaped interviews were transcribed and analysed using content analysis.

FINDINGS

Data analysis identified four themes, which represented different recovery stages: sudden and serious symptoms, nightmares and vivid dreams, physical and emotional disturbances, and establishing a new life after emergency surgery. A fifth theme, support for a new lifestyle, occurred between the four stages.

CONCLUSION

Participants experienced symptoms of physical and psychological stress during the early recovery stages following emergency heart surgery. A lack of understanding of the process of recovery increased these difficulties; participants wanted and needed multidisciplinary care and education. Emergency heart surgery does not allow healthcare professionals to inform patients of what to expect post-surgery. Our findings suggest that rather than waiting until discharge to offer disease information and treatment plans, multidisciplinary care should be initiated as soon as possible to facilitate recovery.

Intra-operative events during cardiac surgery are risk factors for the development of delirium in the ICU

BACKGROUND

Risk factors for delirium following cardiac surgery are incompletely understood. The aim of this study was to investigate whether intra-operative pathophysiological alterations and therapeutic interventions influence the risk of post-operative delirium.

METHODS

This retrospective cohort study was performed in a 12-bed cardiosurgical intensive care unit (ICU) of a university hospital and included patients consecutively admitted after cardiac surgery during a 2-month period. The diagnosis of delirium was made clinically using validated scores. Comparisons between patients with and without delirium were performed with non-parametric tests. Logistic regression was applied to identify independent risk factors. Results are given as number (percent) or median (range).

RESULTS

Of the 194 consecutive post-cardiac surgery patients, 50 (26 %) developed delirium during their ICU stay. Univariate analysis revealed that significant differences between patients with and without delirium occurred in the following intra-operative variables: duration of cardiopulmonary bypass (184 [72-299] vs 113 (37-717) minutes, p < 0.001), lowest mean arterial pressure (50 [30-70] vs 55 [30-75] mmHg, p = 0.004), lowest haemoglobin level (85 [56-133] vs 98 [53-150] g/L, p = 0.005), lowest body temperature (34.5 [24.4-37.2] vs 35.1 [23.9-37.2] °C, p = 0.035), highest noradrenaline support (0.11 [0.00-0.69] vs 0.07 [0.00-0.42] μg/kg/minute, p = 0.001), and frequency of red blood cell transfusions (18 [36 %] vs 26 [18 %], p = 0.018) and platelet transfusions (23 [46 %] vs 24 [17 %], p < 0.001). Only platelet transfusions remained an independent risk factor in the multivariate analysis (p < 0.001).

CONCLUSIONS

In patients undergoing cardiac surgery, various intra-operative events, such as transfusion of platelets, were risk factors for the development of a post-operative delirium in the ICU. Further research is needed to unravel the underlying mechanisms.

Incidence and risk factors for postoperative delirium after major head and neck cancer surgery

BACKGROUND

Postoperative delirium is a common and serious complication after extensive surgery. This study aimed to investigate the incidence and risk factors for postoperative delirium after major head and neck cancer surgery.

METHODS

A retrospective analysis was performed for 293 patients who underwent major head and neck cancer surgery lasting >6 h at our institution between January 2012 and November 2015. All data were assessed by two psychiatrists. Univariate and multivariate analyses were performed.

RESULTS

Postoperative delirium developed in 50 (17.1%) patients; most cases (84.0%) of postoperative delirium were observed between postoperative day (POD) 1 and POD 3. Multivariate analysis revealed that an age >70 years was the significant risk factor for postoperative delirium incidence after major head and neck cancer surgery; the multivariate hazard ratio was 3.935 (95% confidence interval 1.873-8.265, p < 0.001).

CONCLUSIONS

Most cases of postoperative delirium after major head and neck cancer surgery were observed between POD 1 and POD 3, and a multivariate analysis revealed that an age >70 years was a significant risk factor for postoperative delirium incidence. Clinicians should pay particular attention to the possibility of delirium incidence during the first 3 days after surgery for patients aged >70 years.

Risk factors for delirium after on-pump cardiac surgery: a systematic review

Introduction

As evidence-based effective treatment protocols for delirium after cardiac surgery are lacking, efforts should be made to identify risk factors for preventive interventions. Moreover, knowledge of these risk factors could increase validity of etiological studies in which adjustments need to be made for confounding variables. This review aims to systematically identify risk factors for delirium after cardiac surgery and to grade the evidence supporting these associations.

Method

A prior registered systematic review was performed using EMBASE, CINAHL, MEDLINE and Cochrane from 1990 till January 2015 (http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42014007371). All studies evaluating patients for delirium after cardiac surgery with cardiopulmonary bypass (CPB) using either randomization or multivariable data analyses were included. Data was extracted and quality was scored in duplicate. Heterogeneity impaired pooling of the data; instead a semi-quantitative approach was used in which the strength of the evidence was graded based on the number of investigations, the quality of studies, and the consistency of the association reported across studies.

Results

In total 1462 unique references were screened and 34 were included in this review, of which 16 (47 %) were graded as high quality. A strong level of evidence for an association with the occurrence of postoperative delirium was found for age, previous psychiatric conditions, cerebrovascular disease, pre-existent cognitive impairment, type of surgery, peri-operative blood product transfusion, administration of risperidone, postoperative atrial fibrillation and mechanical ventilation time. Postoperative oxygen saturation and renal insufficiency were supported by a moderate level of evidence, and there is no evidence that gender, education, CPB duration, pre-existent cardiac disease or heart failure are risk factors.

Conclusion

Of many potential risk factors for delirium after cardiac surgery, for only 11 there is a strong or moderate level of evidence. These risk factors should be taken in consideration when designing future delirium prevention strategies trials or when controlling for confounding in future etiological studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1060-0) contains supplementary material, which is available to authorized users.

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.

Sleep-disordered breathing is a risk factor for delirium after cardiac surgery: a prospective cohort study

Introduction

Delirium is a frequent complication after cardiac surgery. Although various risk factors for postoperative delirium have been identified, the relationship between nocturnal breathing disorders and delirium has not yet been elucidated. This study evaluated the relationship between sleep-disordered breathing (SDB) and postoperative delirium in cardiac surgery patients without a previous diagnosis of obstructive sleep apnea.

Methods

In this prospective cohort study, 92 patients undergoing elective cardiac surgery with extracorporeal circulation were evaluated for both SDB and postoperative delirium. Polygraphic recordings were used to calculate the apnea-hypopnea index (AHI; mean number of apneas and hypopneas per hour recorded) of all patients preoperatively. Delirium was assessed during the first four postoperative days using the Confusion Assessment Method. Clinical differences between individuals with and without postoperative delirium were determined with univariate analysis. The relationship between postoperative delirium and those covariates that were associated with delirium in univariate analysis was determined by a multivariate logistic regression model.

Results

The median overall preoperative AHI was 18.3 (interquartile range, 8.7 to 32.8). Delirium was diagnosed in 44 patients. The median AHI differed significantly between patients with and without postoperative delirium (28 versus 13; P = 0.001). A preoperative AHI of 19 or higher was associated with an almost sixfold increased risk of postoperative delirium (odds ratio, 6.4; 95% confidence interval, 2.6 to 15.4; P <0.001). Multivariate logistic regression analysis showed that preoperative AHI, age, smoking, and blood transfusion were independently associated with postoperative delirium.

Conclusions

Preoperative SDB (for example, undiagnosed obstructive sleep apnea) were strongly associated with postoperative delirium, and may be a risk factor for postoperative delirium.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-014-0477-1) contains supplementary material, which is available to authorized users.

The pharmacologic treatment of intensive care unit delirium: a systematic review

OBJECTIVE

To systematically evaluate the treatment of ICU delirium.

DATA SOURCES

Literature searches were conducted using PubMed and Ovid MEDLINE (January 1980 to March 2013). Clinical trials/reports evaluating the use of pharmacologic treatment for ICU delirium were selected. References from major guidelines and publications were reviewed.

STUDY SELECTION AND DATA EXTRACTION

English-language articles related to the treatment of ICU delirium were included. The following were excluded: (1) used pharmacologic treatment for the prevention of delirium; (2) inclusion of non-critically ill, palliative care, or hospice care patients; (3) letters to the editor; (4) case studies; (5) case series; (6) studies without delirium-related end points; and (7) studies with a predominantly postoperative population. Data extracted included: study design, population, treatment, number of participants, end points, outcomes/authors' conclusions, and adverse effects.

DATA SYNTHESIS

Four studies were included in this review. The US Preventative Services Task Force classification scheme was used to assess the quality of evidence. All 4 studies reviewed were level I evidence studies. There are few well-designed, randomized studies that evaluate ICU delirium treatment. The 2 main randomized studies have small sample sizes and methodological concerns. Antipsychotic therapy may reduce the duration of ICU delirium. However, more robust studies are needed to demonstrate benefit.

CONCLUSIONS

There is a lack of evidence supporting pharmacologic treatment for ICU delirium. Prospective, well-designed studies using proper delirium identification tools and severity are necessary to confirm the overall impact of pharmacologic therapy on the duration of delirium and associated complications.

Cigarette smoking as a risk factor for delirium in hospitalized and intensive care unit patients. A systematic review

BACKGROUND

Active smokers are prevalent in hospitalized and critically ill patients. Cigarette smoking and nicotine withdrawal may increase delirium in these populations. This systematic review aims to determine whether active cigarette smoking increases the risk for delirium in hospitalized and intensive care unit (ICU) patients.

METHODS

A systematic search of English-, Spanish-, and French-language articles published from 1966 to April 2013 was performed. Studies were included if they measured cigarette smoking as a risk factor and delirium as an outcome in adult hospitalized or ICU patients. Methodologic quality of studies was assessed using both the validated Newcastle Ottawa Scale and an additional evidence-based quality rating scale.

RESULTS

A total of 14 cohort studies of surgical and ICU populations were included in the review. No studies in non-ICU inpatients were identified. The incidence of delirium ranged from 9 to 52%, and the prevalence of active smokers ranged from 9 to 44%. The quality of assessment for active smoking varied widely. None of the studies used biochemical measures to determine cigarette smoke exposure. Of the six studies restricting the smoking group to active smokers only, active smoking was independently associated with delirium in one study, trended toward an association in one study, and showed a dose response in one study. Quantitative summary measures were not calculated due to study heterogeneity and missing data.

CONCLUSIONS

There is currently insufficient evidence to determine if cigarette smoking is a risk factor for delirium. Future studies should consider using biochemical measures of cigarette smoke exposure to objectively quantify smoking behavior.

Dexmedetomidine: a review of applications for cardiac surgery during perioperative period

Cardiac surgery is associated with a high incidence of cardiovascular and other complications during the perioperative period that translate into increased mortality and prolonged hospital stays. Safe comprehensive perioperative management is required to eliminate these adverse events. Dexmedetomidine is a selective α2-adrenoreceptor agonist that has been described as an ideal medication in the perioperative period of cardiac surgery. The major clinical effects of dexmedetomidine in this perioperative period can be summarized as attenuating the hemodynamic response, cardioprotective effects, antiarrhythmic effects, sedation in the ICU setting, treatment of delirium, and procedural sedation. Although there are some side effects of dexmedetomidine, it is emerging as an effective therapeutic agent in the management of a wide range of clinical conditions with an efficacious, safe profile. The present review serves as an overview update in the diverse applications of dexmedetomidine for cardiac surgery during the perioperative period.

Delirium in patients admitted to a cardiac intensive care unit with cardiac emergencies in a developing country: incidence, prevalence, risk factor and outcome

AIM

To assess the incidence, prevalence, risk factors and outcome of delirium in patients admitted to a cardiac intensive care unit (ICU) of a tertiary care hospital.

METHODS

Three hundred nine consecutive patients admitted to a 22-bed coronary care unit were screened for presence of delirium by using Confusion Assessment Method for Intensive Care Unit (CAM-ICU), and those found positive on CAM-ICU were further evaluated by a psychiatrist to confirm the diagnosis of delirium as per DSM-IV-TR criteria. Patients were also evaluated for the risk factors for delirium and outcome of delirium.

RESULTS

Incidence rate of delirium was 9.27%, and prevalence rate was 18.77%. The risk factors identified for delirium in binary logistic regression analysis were hypokalemia, Sequential Organ Failure Assessment score, presence of cognitive deficits, receiving more than three medications, sepsis, hyponatremia, presence of cardiogenic shock, having undergone coronary artery bypass grafting, left ventricular ejection fraction <30, currently receiving opioids, age more than 65 years, presence of diabetes mellitus, presence of uncontrolled diabetes mellitus, history of seizures, presence of congestive cardiac failure, having undergone angioplasty, presence of atrial fibrillation, ongoing depression, currently receiving/taking benzodiazepines, warfarin, ranitidine, steroids, non-steroidal anti-inflammatory drugs, higher total number of medications, presence of raised creatinine, anaemia, hypoglycemia, Acute Physiology and Chronic Health Evaluation II score and Charlson Comorbidity Index score. About one fourth (n=22; 27%) of the patients who developed delirium died during the hospital stay in contrast to 1% mortality in the non-delirious group. Those with delirium also had longer stay in the ICU.

CONCLUSIONS

Delirium is highly prevalent in the cardiac ICU setting and is associated with presence of many modifiable risk factors. Development of delirium increases the mortality risk and is associated with longer cardiac ICU stay.

Delirium risk prediction, healthcare use and mortality of elderly adults in the emergency department

OBJECTIVES

To create a risk prediction rule for delirium in elderly adults in the emergency department (ED) and to compare mortality and resource use of elderly adults in the ED with and without delirium.

DESIGN

Prospective observational study.

SETTING

Urban tertiary care ED.

PARTICIPANTS

Individuals aged 65 and older presenting for ED care (N = 700).

MEASUREMENTS

A trained research assistant performed a structured mental status assessment and attention tests, after which delirium was determined using the Confusion Assessment Method. Data were collected on participant demographics, comorbidities, medications, ED course, hospital and intensive care unit (ICU) admission, length of stay, hospital charges, 30-day rehospitalization, and mortality.

RESULTS

Nine percent of elderly study participants had delirium. Using logistic regression, a delirium prediction rule consisting of older age, prior stroke or transient ischemic attack, dementia, suspected infection, and acute intracranial hemorrhage was created had good predictive accuracy (area under the receiver operating characteristic curve = 0.77). Admitted participants with ED delirium had longer median lengths of stay (4 vs 2 days) and were more likely to require ICU admission (13% vs 6%) and to be discharged to a new long-term care facility (37% vs 9%) than those without. In all participants, ED delirium was associated with higher 30-day mortality (6% vs 1%) and 30-day readmission (27% vs 13%).

CONCLUSION

This risk prediction rule may help identify a group of individuals in the ED at high risk of developing delirium who should undergo screening, but it requires external validation. Identification of delirium in the ED may enable physicians to implement strategies to decrease delirium duration and avoid inappropriate discharge of individuals with acute delirium, improving outcomes.

White-matter hyperintensities predict delirium after cardiac surgery

OBJECTIVES

Postoperative delirium is a common psychiatric disorder among patients who undergo cardiac surgery. Although several studies have investigated risk factors for delirium after cardiac surgery, the association between delirium and cerebral white-matter hyperintensities (WMH) on magnetic resonance (MR) imaging has not been previously studied. The aim of this study was to identify general risk factors for delirium, as well as to examine the specific relationship between WMH and delirium.

DESIGN

Retrospective chart review.

SETTING

University hospital.

PARTICIPANTS

A total of 130 patients who underwent cardiac surgery.

MEASUREMENTS

Variables recorded included patient demographics, comorbidities, mental health, laboratory data, surgical information, and cerebrovascular disease. The presence of WMH was assessed using MR images. Two groups of patients were compared (patients with and without delirium) using both univariate and multiple logistic analyses.

RESULTS

Delirium occurred in 18 patients (13.8%) and patients with delirium were significantly older than patients who did not develop delirium. The prevalence of severe WMH (Fazekas score = 3) was significantly higher in patients with delirium. Three independent predictors of delirium were identified: abnormal creatinine (odds ratio [OR]: 4.5; 95% confidence interval [CI]: 1.4-13.9), severe WMH (OR: 3.9; 95% CI: 1.2-12.5), and duration of surgery (OR: 1.4; 95% CI: 1.0-1.8).

CONCLUSIONS

The results of this study suggest that white-matter abnormality is one of the most important risk factors for development of delirium after cardiac surgery. These factors can be used for prediction and prevention of delirium following cardiac surgery.

Delirium in the cardiovascular ICU: exploring modifiable risk factors

OBJECTIVE

Delirium, an acute organ dysfunction, is common among critically ill patients leading to significant morbidity and mortality; its epidemiology in a mixed cardiology and cardiac surgery ICU is not well established. We sought to determine the prevalence and risk factors for delirium among cardiac surgery ICU patients.

DESIGN

Prospective observational study.

SETTING

Twenty-seven-bed medical-surgical cardiac surgery ICU.

PATIENTS

Two hundred consecutive patients with an expected cardiac surgery ICU length of stay >24 hrs.

INTERVENTIONS

None.

MEASUREMENTS

Baseline demographic data and daily assessments for delirium using the validated and reliable Confusion Assessment Method for the ICU were recorded, and quantitative tracking of delirium risk factors were conducted. Separate analyses studied the role of admission risk factors for occurrence of delirium during the cardiac surgery ICU stay and identified daily occurring risk factors for the development of delirium on a subsequent cardiac surgery ICU day.

MAIN RESULTS

Prevalence of delirium was 26%, similar among cardiology and cardiac surgical patients. Nearly all (92%) exhibited the hypoactive subtype of delirium. Benzodiazepine use at admission was independently predictive of a three-fold increased risk of delirium (odds ratio 3.1 [1, 9.4], p = 0.04) during the cardiac surgery ICU stay. Of the daily occurring risk factors, patients who received benzodiazepines (2.6 [1.2, 5.7], p = 0.02) or had restraints or devices that precluded mobilization (2.9 [1.3, 6.5], p < 0.01) were more likely to have delirium the following day. Hemodynamic status was not associated with delirium.

CONCLUSIONS

Delirium occurred in one in four patients in the cardiac surgery ICU and was predominately hypoactive in subtype. Chemical restraints via use of benzodiazepines or the use of physical restraints/restraining devices predisposed patients to a greater risk of delirium, pointing to areas of quality improvement that would be new to the vast majority of cardiac surgery ICUs.

Meta-analysis of factors which influence delirium following cardiac surgery

BACKGROUND

The aim of this study is to determine the risk factors of delirium after cardiac surgery.

METHODS

A systematic literature search of MEDLINE, EMBASE, the Cochrane Library, and Science Citation Index limited to 2008 to 2011 and review of studies was conducted. Eligible studies were of randomized controlled trials or cohort studies, using delirium assessment tool, reporting at least one risk factor associated with delirium, and available to full text.

RESULTS

The search identified 106 potentially relevant publications; only 25 met selection criteria. Our systematic review revealed 33 risk factors: 17 predisposing and 16 precipitating factors for delirium after elective cardiac surgery. The most established predisposing risk factors were age, depression, and history of stroke, cognitive impairment, diabetes mellitus, and atrial fibrillation. The most established precipitating risk factors were duration of surgery, prolonged intubation, surgery type, red blood cell transfusion, elevation of inflammatory markers and plasma cortisol level, and postoperative complications. Moreover, sedation with dexmedetomidine may significantly predict the absence of postoperative delirium.

CONCLUSIONS

Postoperative delirium is related to several risk factors following cardiac surgery. Sedation with dexmedetomidine and fast-track weaning protocols may decrease the incidence of delirium in cardiac surgical patients.

Incidence, prevalence, risk factor and outcome of delirium in intensive care unit: a study from India

OBJECTIVE

To evaluate the incidence, prevalence, risk factors and outcome of delirium in the respiratory intensive care unit of a tertiary care hospital.

METHODS

Consecutive patients admitted to an eight-bed respiratory intensive care unit were screened for presence of delirium by a psychiatrist. Patients found to have delirium were evaluated using univariate techniques for their clinical profiles, risk factors for delirium, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, duration of stay (in days) and outcome at discharge from intensive care unit besides evaluation on Delirium Rating Scale-Revised 98 version (DRS-R-98).

RESULTS

Incidence and prevalence rate of delirium were 24.4% and 53.6% respectively. Univariate analyses revealed that the prevalence of delirium was higher (64%) in mechanically ventilated patients. The predisposing risk factors identified for delirium in univariate analysis were higher age; higher Glasgow Coma Scale score; increased APACHE II score; hyperuricemia; hypoalbuminemia; presence of acidosis; abnormal alkaline transferase levels; use of mechanical ventilation; higher number of total medication received and use of sedative, steroids and insulin. Univariate analysis showed that patients who were diagnosed with delirium had significantly longer duration of intensive care unit (ICU) stay and higher mortality rates. Age, multiple organ failure, hypoactive delirium and higher DRS-R-98 scores were significant risk factors for mortality in patients with delirium.

CONCLUSIONS

Delirium is highly prevalent in the ICU setting and delirium is associated with longer ICU stay and higher mortality.

Incidence and risk factors of postoperative delirium in patients with esophageal cancer

BACKGROUND

Postoperative delirium is a common complication after major surgery and is characterized by acute confusion with fluctuating consciousness. The aim of this study was to investigate the incidence and risk factors of postoperative delirium in patients with esophageal cancer.

METHODS

We conducted a retrospective cohort analysis of 306 consecutive patients who had undergone an esophagectomy at Keio University Hospital from January 1998 to December 2009. All data were assessed by psychiatrists, and delirium was diagnosed according to criteria of the Diagnostic and Statistical Manual Disorder, fourth edition. Univariate and multivariate analyses were performed.

RESULTS

Postoperative delirium developed in 153 (50.0 %) of 306 patients. One hundred fourteen (37.3 %) of the 306 patients required psychoactive medication for symptoms associated with delirium. Univariate analyses showed that older age, male gender, additional flunitrazepam for sedation in intensive care unit (ICU) after surgery, longer periods of time under mechanical ventilation after surgery, longer ICU stays, occurrence of postoperative complications, and longer hospital stays were significantly associated with postoperative delirium. Multivariate analysis revealed that development of delirium was linked to older age, additional flunitrazepam in ICU, and occurrence of postoperative complication.

CONCLUSIONS

The development of postoperative delirium in patients with esophageal cancer is a problem that cannot be ignored. Our results suggest that the risk of developing delirium is associated with older age, use of flunitrazepam in ICU, and postoperative complications.

Delirium in older adults

Delirium is a common neuropsychiatric syndrome in the elderly that can occur in several different settings caused by several different processes. It is common and causes increased morbidity and mortality to those affected. This clinical review discusses the prediction, prevention, diagnosis, and treatment of delirium in the elderly population. Several strategies to predict delirium are noted with the discussion of pharmacological and nonpharmacological trials of prevention and treatment. Diagnosis of delirium, specifically with the use of objective instruments, is discussed, as is the evidence for pharmacological and nonpharmacological treatment strategies. Discussion of the neurobiology and genetic markers for delirium may elucidate further areas for future research.