Incidence and predictors of delirium after cardiac surgery: Results from The IPDACS Study

Different MMSE Score Is Associated with Postoperative Delirium in Young-Old and Old-Old Adults

Background

Postoperative delirium is one of the most common postoperative complications in geriatric patients. Mini-mental state examination (MMSE) assesses cognitive function in patients and is associated with postoperative delirium. However, whether there is an age-dependent relationship between preoperative MMSE score and postoperative delirium remains unknown.

Methods

We therefore set out to investigate the association between preoperative MMSE score and postoperative delirium in young-old (≤80 year-old, 75.46±4.69 years, 27.0% male, n = 63) and old-old (>80 year-old, 84.51±3.46 years, 20.9% male, n = 67) participants, who had repairs of hip fractures under general anesthesia. The Confusion Assessment Method and Memorial Delirium Assessment Scale were administrated before surgery, and on the first, second and fourth days after surgery, to assess the incidence and severity of the delirium, respectively. A receiver operating characteristic curve analysis was used to calculate the optimal cutoff score of MMSE in predicting postoperative delirium.

Results

Thirty-four (26.2%) of 130 patients (80.12±6.12 years, 23.8% male) developed postoperative delirium. Preoperative MMSE scores were negatively associated with higher incidences and greater severity of postoperative delirium. The optimal cutoff scores of MMSE associated with postoperative delirium for young-old and old-old participants were 18.4 and 21.4, with a sensitivity of 60% and 83.8%, and a specificity of 92.5% and 62.8%, respectively.

Conclusion

The data demonstrated the optimal cutoff score of MMSE associated with postoperative delirium in young-old adults might be lower than that in old-old adults. Pending further investigation, these findings suggest that the association between preoperative MMSE score and postoperative delirium is age-dependent.

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.

Pre- and Intraoperative Predictors of Delirium after Open Abdominal Aortic Aneurysm Repair

OBJECTIVES

We reviewed our series of patients who underwent open abdominal aortic aneurysm (AAA) repair and constructed a prediction model for postoperative delirium.

METHODS

397 patients who underwent open AAA repair at our institution between April 2005 and June 2013 were retrospectively reviewed. Postoperative delirium was diagnosed from the patients' medical records according to the Diagnostic and Statistical Manual of Mental Disorders 4th Edition (DSM-IV) criteria. Mental alterations resulting from postoperative cerebrovascular events or preexisting mental disorders were excluded. Parameters with significant differences on univariate analysis were subjected to a logistic regression analysis.

RESULTS

There were 46 patients (11.5%) diagnosed with postoperative delirium. The following parameters were significant in the univariate analysis: age, history of stroke, hyperlipidemia, forced expiratory volume in 1 s (FEV1), percent vital capacity (%VC), and blood urea nitrogen (BUN) level. A logistic regression analysis revealed that an age ≥70 years (odds ratio [95% confidence interval], 3.342 [1.437-7.774]), blood loss ≥1517 mL (2.707 [1.359-5.391]), and the absence of hyperlipidemia (2.154 [1.060-4.374]) were significant risk factors.

CONCLUSIONS

Older patients with substantial intraoperative blood loss require highly vigilant postoperative care. Further studies are necessary to elucidate the relationship between cholesterol and delirium.

Melatonin treatment in the prevention of postoperative delirium in cardiac surgery patients

Introduction

Post-cardiac surgery delirium is a severe complication. The circadian rhythm of melatonin secretion has been shown to be altered postoperatively.

Aim of the study

It was hypothesized that restoring normal sleeping patterns with a substance that is capable of resynchronizing circadian rhythm such as exogenous administration of melatonin may possibly reduce the incidence of postoperative delirium.

Material and methods

This paper represents a prospective clinical observational study. Two consecutive groups of 250 consecutive patients took part in the study. Group A was the control group and group B was the melatonin group. In group B, the patients received prophylactic melatonin treatment. The main objectives were to observe the incidence of delirium, to identify any predictors of delirium, and to compare the two groups based on the delirium incidence.

Results

The incidence of delirium was 8.4% in the melatonin group vs. 20.8% in the control group (p = 0.001). Predictors of delirium in the melatonin group were age (p = 0.001) and higher EuroSCORE II value (p = 0.001). In multivariate analysis, age and EuroSCORE II value (p = 0.014) were predictors of postoperative delirium. Comparing the groups, the main predictors of delirium were age (p = 0.001), EuroSCORE II value (p = 0.001), cardio-pulmonary bypass (CPB) time (p = 0.001), aortic cross-clamping (ACC) time (p = 0.008), sufentanil dose (p = 0.001) and mechanical ventilation (p = 0.033).

Conclusions

Administration of melatonin significantly decreases the incidence of postoperative delirium after cardiac surgery. Prophylactic treatment with melatonin should be considered in every patient scheduled for cardiac surgery.

Mild cognitive impairment with associated inflammatory and cortisol alterations as independent risk factor for postoperative delirium

AIMS

The present study aimed to determine the impact of mild cognitive impairment (MCI) on the development of postoperative delirium and, secondly, to assess the association between MCI and raised perioperative cortisol, cytokine, cobalamin and homocysteine levels.

METHODS

The study recruited 113 consecutive adult patients scheduled for cardiac surgery with cardiopulmonary bypass. The patients were examined preoperatively with the Montreal Cognitive Assessment and Trail Making Test. A diagnosis of MCI was established based upon the criteria of the National Institute on Aging and Alzheimer's Association. Patients were screened for delirium within the first 5 days postoperatively.

RESULTS

MCI was diagnosed in 24.8% of the patients, whereas the frequency of delirium was 36%. A multivariate analysis demonstrated that individuals with MCI were at a significantly higher risk of postoperative delirium (OR = 6.33, p = 0.002). Preoperative cortisol, postoperative cortisol and IL-2 plasma levels were higher in the MCI group as compared to non-MCI subjects.

CONCLUSION

MCI is associated with a higher risk of postoperative delirium. Perioperative cortisol and inflammatory alterations observed in MCI may provide a physiological explanation for this increased risk.

Outcomes associated with postoperative delirium after cardiac surgery

BACKGROUND

Delirium after surgery is a common condition that leads to poor outcomes. Few studies have examined the effect of postoperative delirium on outcomes after cardiac surgery.

OBJECTIVES

To assess the relationship between delirium after cardiac surgery and the following outcomes: length of stay after surgery, prevalence of falls, discharge to a nursing facility, discharge to home with home health services, and use of inpatient physical therapy.

METHODS

Electronic medical records of 656 cardiac surgery patients were reviewed retrospectively.

RESULTS

Postoperative delirium occurred in 161 patients (24.5%). Patients with postoperative delirium had significantly longer stays (P < .001) and greater prevalence of falls (P < .001) than did patients without delirium. Patients with delirium also had a significantly greater likelihood for discharge to a nursing facility (P < .001) and need for home health services if discharged to home (P < .001) and a significantly higher need for inpatient physical therapy (P < .001). Compared with patients without postoperative delirium, patients who had this complication were more likely to have received zolpidem and benzodiazepines postoperatively and to have a history of arrhythmias, renal disease, and congestive heart failure.

CONCLUSIONS

Patients who have delirium after cardiac surgery have poorer outcomes than do similar patients without this complication. Development and implementation of an extensive care plan to address postoperative delirium is necessary for cardiac surgery patients who are at risk for or have delirium after the surgery.

Risk factors for postoperative delirium in patients after coronary artery bypass grafting: A prospective cohort study

PURPOSE

This study was designed to identify the incidence and independent perioperative risk factors associated with postoperative delirium of patients who underwent coronary artery bypass grafting (CABG) in a large intensive care unit setting in China.

METHODS

Delirium was diagnosed by the confusion assessment method for the intensive care unit (CAM-ICU). Baseline demographics, perioperative data, and postoperative outcomes of 249 consecutive patients who underwent CABG were recorded prospectively and analyzed via univariate analysis and multivariate logistic regression to determine the independent risk factors of postoperative delirium.

RESULTS

Postoperative delirium was detected in 76 patients according to CAM-ICU criteria. The incidence was 30.52%. Patients with and without delirium differed significantly on 34 variables (P < .05). Multivariate logistic regression analysis revealed that preoperative atrial fibrillation (odds ratio [OR], 3.957; 95% confidence interval [CI], 1.727-9.066), elevated European system for cardiac operative risk evaluation (OR, 1.178; 95% CI, 1.018-1.364), cognitive impairment (OR, 3.231; 95% CI, 1.008-10.356), prolonged surgery duration (OR, 1.008; 95% CI, 1.003-1.014), postoperative poor quality of sleep (OR, 5.001; 95% CI, 2.476-10.101), and electrolyte disturbance (OR, 2.095; 95% CI, 1.041-4.216) were independently associated with postoperative delirium after CABG.

CONCLUSIONS

Delirium is a frequent complication. Factors independently associated with delirium are preoperative atrial fibrillation, elevated European system for cardiac operative risk evaluation and cognitive impairment, longer surgery duration, postoperative poor quality of sleep, and electrolyte disturbance. The study may be helpful in decreasing the incidence of postoperative delirium after CABG by treating these predictors properly.

The assessment of the T102C polymorphism of the 5HT2a receptor gene, 3723G/A polymorphism of the NMDA receptor 3A subunit gene (GRIN3A) and 421C/A polymorphism of the NMDA receptor 2B subunit gene (GRIN2B) among cardiac surgery patients with and without delirium

OBJECTIVE

The studies regarding the role of genes polymorphism in development of postoperative delirium are extremely rare. Therefore, we investigated the potential association of polymorphism in 5HT2a receptor gene and N-methyl-d-aspartate (NMDA) receptor 3A and 2B subunits genes with postoperative delirium.

METHOD

We conducted a prospective, nested, case-control study. For analysis, 3723 G/A (rs3739722) polymorphism in the GRIN3A gene, 421 C/A (rs3764028) polymorphism in the GRIN2B gene and T102C (rs6313) polymorphism in the 5HT2A gene were selected.

RESULTS

Genetic analysis confirmed that there were significant differences in genotype frequencies for 3723 G/A between delirium patients and controls. No other significant associations were observed. Moreover, according to the multivariate conditional logistic regression analysis the presence of AG haplotype of GRIN3A gene was independently associated with postoperative delirium.

CONCLUSIONS

These findings suggest that the genetic variations of NR3A subunit of NMDA receptor may be a predisposing factor to delirium among the Polish population of cardiac surgery patients.

Delirium affects length of hospital stay after lung transplantation

BACKGROUND

Delirium is relatively common after lung transplantation, although its prevalence and prognostic significance have not been systematically studied. The purpose of the present study was to examine pretransplant predictors of delirium and the short-term impact of delirium on clinical outcomes among lung transplant recipients.

METHODS

Participants underwent pretransplant cognitive testing using the Repeatable Battery for the Assessment of Neuropsychological Status and the Trail Making Test. After transplant, delirium was assessed using the Confusion Assessment Method until discharge.

RESULTS

Sixty-three patients were transplanted between March and November 2013, of which 23 (37%) developed delirium. Among transplanted patients, 48 patients completed pretransplant cognitive testing. Better pretransplant cognitive function was associated with lower risk of delirium (odds ratio, 0.69 [95% confidence interval 0.48, 0.99], P = .043); and demographic and clinical features including native disease (P = .236), the Charlson comorbidity index (P = .581), and the lung allocation score (P = .871) were unrelated to risk of delirium, although there was a trend for women to experience delirium less frequently (P = .071). The presence (P = .006) and duration (P = .027) of delirium were both associated with longer hospital stays.

CONCLUSION

Delirium occurs in more than one-third of patients after lung transplantation. Delirium was associated with poorer pretransplant cognitive functioning and longer hospital stays, after accounting for other medical and demographic factors.

The Prevention of Delirium and Complications Associated with Surgical Treatments (PODCAST) study: protocol for an international multicentre randomised controlled trial

INTRODUCTION

Postoperative delirium is one of the most common complications of major surgery, affecting 10-70% of surgical patients 60 years and older. Delirium is an acute change in cognition that manifests as poor attention and illogical thinking and is associated with longer intensive care unit (ICU) and hospital stay, long-lasting cognitive deterioration and increased mortality. Ketamine has been used as an anaesthetic drug for over 50 years and has an established safety record. Recent research suggests that, in addition to preventing acute postoperative pain, a subanaesthetic dose of intraoperative ketamine could decrease the incidence of postoperative delirium as well as other neurological and psychiatric outcomes. However, these proposed benefits of ketamine have not been tested in a large clinical trial.

METHODS

The Prevention of Delirium and Complications Associated with Surgical Treatments (PODCAST) study is an international, multicentre, randomised controlled trial. 600 cardiac and major non-cardiac surgery patients will be randomised to receive ketamine (0.5 or 1 mg/kg) or placebo following anaesthetic induction and prior to surgical incision. For the primary outcome, blinded observers will assess delirium on the day of surgery (postoperative day 0) and twice daily from postoperative days 1-3 using the Confusion Assessment Method or the Confusion Assessment Method for the ICU. For the secondary outcomes, blinded observers will estimate pain using the Behavioral Pain Scale or the Behavioral Pain Scale for Non-Intubated Patients and patient self-report.

ETHICS AND DISSEMINATION

The PODCAST trial has been approved by the ethics boards of five participating institutions; approval is ongoing at other sites. Recruitment began in February 2014 and will continue until the end of 2016. Dissemination plans include presentations at scientific conferences, scientific publications, stakeholder engagement and popular media.

REGISTRATION DETAILS

The study is registered at clinicaltrials.gov, NCT01690988 (last updated March 2014). The PODCAST trial is being conducted under the auspices of the Neurological Outcomes Network for Surgery (NEURONS).

TRIAL REGISTRATION NUMBER

NCT01690988 (last updated December 2013).

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.

Factors associated with post-surgical delirium in patients undergoing open heart surgery

OBJECTIVE

The objective of the present study is to determine the incidence of delirium and the associated factors in patients undergoing open heart surgery.

METHOD

This is an Analytic-descriptive study conducted on 404 patients undergoing elective open heart surgery in Fatemeh Zahra Heart Center, Sari, over the period of 6 months from July to December 2011. Sampling was achieved in a nonrandomized targeted manner and delirium was assessed using NeeCham questionnaire. A trained nurse evaluated the patients for delirium and completed the risk factor checklist on days 1 to 5 after surgery. Data analyses were accomplished using survival analysis (Kaplan-Meier and Cox regression) on SPSS software version 15.

RESULTS

We found that variables, including ventilation time, increased drainage during the first 24 hours, the need for re-operation in the first 24 hours, dysrhythmias, use of inotropic agents, increased use of analgesics, increased arterial carbon dioxide, lack of visitors, and use of physical restrainers were associated with the development of delirium. In addition, we found a delirium incidence of 29%.

CONCLUSION

Diagnosis of cognitive disorders is of utmost value; therefore, further studies are required to clarify the risk factors because controlling them will help prevent delirium.

Delirium and depression: inter-relationship and clinical overlap in elderly people

Delirium and depression are complex neuropsychiatric syndromes common in the elderly and are associated with poor health-care outcomes. Accurate diagnosis is essential to the provision of optimum health care for individuals with these conditions but is complicated by substantial clinical overlap in symptoms and comorbidities. A careful assessment of the patient's symptoms, including their context and time course, is needed for accurate diagnosis. Previous depression is common in patients with delirium and depressive illness is a recognised sequelae of delirium. The two syndromes seem to be caused by similar pathophysiological mechanisms, involving disturbances in stress and inflammatory responses, monoaminergic and melatonergic signalling, which point to new avenues for therapeutic intervention. Improved methods to assess delirium and depression in populations at high risk by virtue of their age, diminished cognitive reserve and physical frailty is a key target to achieve improved health-care outcomes in elderly individuals.

Current readings: neurocognitive impairment and clinical implications after cardiac surgery

The earliest reports of cardiac surgery literatures reported evidence of neurocognitive decline, highlighted in the 1995 statement of Consensus on assessment of neurobehavioral outcomes after cardiac surgery. Until now, the magnitude and clinical importance of neurocognitive outcomes continues to fluctuate and lack clarity. The aim of this review is to evaluate the contemporary status of neurocognitive outcomes in relation to pre-existing impairment, revascularization strategy, broader cardiovascular pathophysiological processes, and any longer-term clinical implications. Five studies published between 2009 and 2013 were reviewed. A meta-analysis did not find differences between on- and off-pump procedures. In other studies, there was evidence for extensive preoperative neurocognitive impairments. Additional 2 studies showed that longer-term neurocognitive impairment, including dementia, was not dissimilar to nonsurgical patients with cardiovascular disease. Currently, there is no convincing evidence to suggest that cardiac surgery, and cardiopulmonary bypass in particular, has a causal role in progression to dementia, or long-term deficit, independent of pre-existing neurocognitive impairments and cardiovascular disease.

Practical assessment of delirium in palliative care

CONTEXT

Delirium is a common, distressing neuropsychiatric complication for patients in palliative care settings, where the need to minimize burden yet accurately assess delirium is hugely challenging.

OBJECTIVES

This review focused on the optimal clinical and research application of delirium assessment tools and methods in palliative care settings.

METHODS

In addition to multidisciplinary input from delirium researchers and other relevant stakeholders at an international meeting, we searched PubMed (1990-2012) and relevant reference lists to identify delirium assessment tools used either exclusively or partly in the context of palliative care.

RESULTS

Of the 26 delirium scales identified, we selected six for in-depth review: three screening tools, two severity measures, and one research tool for neuropsychological assessment of delirium. These tools differed regarding intended use, ease of use, training requirements, psychometric properties, and validation in or suitability for palliative care populations. The Nursing Delirium Screening Scale, Single Question in Delirium, or Confusion Assessment Method, ideally with a brief attention test, can effectively screen for delirium. Favoring inclusivity, use of Diagnostic and Statistical Manual of Mental Disorders-IV criteria gives the best results for delirium diagnosis. The Revised Delirium Rating Scale and the Memorial Delirium Assessment Scale are the best available options for monitoring severity, and the Cognitive Test for Delirium provides detailed neuropsychological assessment for research purposes.

CONCLUSION

Given the unique characteristics of patients in palliative care settings, further contextually sensitive studies of delirium assessment are required in this population.

Preexisting cognitive status is associated with reduced behavioral functional capacity in patients 3 months after cardiac surgery: an extension study

OBJECTIVE

To examine whether preexisting cognitive status rather than short- and middle-term postoperative cognitive decline (POCD) may differentially account for behavioral functional capacity 3 months after cardiac surgery.

METHOD

Seventy-nine patients completed a psychological evaluation, including the Trail Making Test Part B, the memory with 10-s interference, the phonemic fluency and the Instrumental Activities of Daily Living (IADLs) questionnaire for cognitive functions and behavioral functional capacity, respectively, before surgery, at discharge and at 3-month follow-up.

RESULTS

Thirty-one (39%) and 22 (28%) patients showed POCD at discharge and at 3-month follow-up, respectively. Preoperative cognitive status was significantly associated with change in behavioral functional capacity 3 months after surgery (Ps<.003), whereas short- and middle-term POCD and intraoperative risk factors were unrelated to residualized change in IADLs scores (all Ps>.095).

CONCLUSIONS

Preexisting cognitive deficit, especially working memory deficit, rather than short- and middle-term POCD related to intraoperative risk factors is associated with poor behavioral functional capacity 3 months after cardiac surgery. The present study therefore suggests that a preoperative cognitive evaluation is essential to anticipate which patients are likely to show a decline in behavioral functional capacity after cardiac surgery.

Raised IL-2 and TNF-α concentrations are associated with postoperative delirium in patients undergoing coronary-artery bypass graft surgery

BACKGROUND

The knowledge base regarding the pathogenesis of postoperative delirium is limited. The primary aim of this study is to investigate whether increased levels of IL-2 and TNF-α are associated with delirium in patients who underwent coronary-artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB). The secondary aim is to establish whether any association between raised cytokine levels and delirium is related to surgical and anesthetic procedures or mediated by pre-existing conditions associated with raised cytokine levels, such as major depressive disorder (MDD), cognitive impairment, or aging.

METHODS

Patients were examined and screened for MDD and cognitive impairment one day preoperatively, using the Mini International Neuropsychiatric Interview and The Montreal Cognitive Assessment and Trail Making Test Part B. Blood samples were collected postoperatively for cytokine levels.

RESULTS

Postoperative delirium screening was found positive in 36% (41 of 113) of patients. A multivariate logistic regression revealed that an increased concentration of pro-inflammatory cytokines is associated with delirium, and related to advancing age, preoperative cognitive decline of participants, and duration of CPB. According to receiver operating characteristic analysis, the most optimal cut-off for IL-2 and TNF-α concentrations in predicting the development of delirium were 907.5 U/ml and 10.95 pg/ml, respectively.

CONCLUSIONS

The present study suggests that raised postoperative cytokine concentrations are associated with delirium after CABG surgery. Postoperative monitoring of pro-inflammatory markers combined with regular surveillance may be helpful in the early detection of postoperative delirium in this patient group.

Evaluation of the prevalence and risk factors of delirium in cardiac surgery ICU

INTRODUCTION

Delirium is defined as an acute cognitive disorder presenting with fluctuation in cognition, apathy and non-organized thinking. It may increase morbidity, mortality, ICU stay and cost. In patients who underwent heart surgery delirium may increase post-operative complications such as respiratory insufficiency, sternum instability and need to re-operation of the sternum. The aim of this study was to evaluate the prevalence and risk factors of delirium in patients admitted to cardiac surgery.

MATERIALS AND METHODS

18 years or older patients who had undergone cardiac surgeries and stayed for more than 24 hours in ICU following surgery were recruited. All subjects were assessed for signs &amp; symptoms of delirium using CAM-ICU and its risk factors. All data were analyzed by SPSS 16 at the end of the study.

RESULTS

The prevalence of delirium in these patients was 23.5% (47 patients). The mean age of patients with delirium was more than other patients (P=0.001). The Incidence of delirium in the patients with cardiopulmonary bypass surgery (CPB) was higher than the patients without CPB (P=0.01). The Incidence of delirium in the patients with Atrial fibrillation was higher than patients without it (P=0.002). The Incidence of delirium in the patients with CVA history was higher than the patients without CVA history (P=0.032). The mean time of mechanical ventilation in the delirious patients was more than other patients (P=0.01).

CONCLUSION

Older Age, CPB, history of CVA, Atrial Fibrillation, and prolonged mechanical ventilation are considered as the risk factors of delirium in cardiac surgery patients.

Perioperative psycho-educational intervention can reduce postoperative delirium in patients after cardiac surgery: a pilot study

OBJECTIVE

Postoperative delirium after cardiac surgery is associated with many consequences such as poorer functional recovery, more frequent postoperative complications, higher mortality, increased length of hospital stay, and higher hospital costs. The aim of this study was to evaluate the efficacy of perioperative psycho-educational intervention in preventing postoperative delirium in post cardiac surgery patients.

METHOD

We conducted a comparative retrospective study between 49 patients who had received perioperative psycho-educational intervention and 46 patients who had received standard care. The primary outcome was the incidence of postoperative delirium. Secondary outcomes included length of ICU stay, and severity and duration of postoperative delirium among the patients who had developed delirium.

RESULTS

The incidence of postoperative delirium was significantly lower in the intervention group than that in the control group (12.24% vs. 34.78%, P = 0.009). Among the patients who had developed postoperative delirium, there was no statistical difference between the two groups regarding secondary outcomes.

CONCLUSIONS

Our results show that the patients who received perioperative psycho-educational intervention were associated with a lower incidence of postoperative delirium after cardiac surgery than those who received standard care. Clinicians would be able to implement this psycho-educational intervention as part of routine practice to reduce delirium.

Predisposing and precipitating factors of delirium after cardiac surgery: a prospective observational cohort study

OBJECTIVE

To comprehensively assess pre-, intra-, and postoperative delirium risk factors as potential targets for intervention.

BACKGROUND

Delirium after cardiac surgery is associated with longer intensive care unit (ICU) stay, and poorer functional and cognitive outcomes. Reports on delirium risk factors so far did not cover the full range of patients' presurgical conditions, intraoperative factors, and postoperative course.

METHODS

After written informed consent, 221 consecutive patients ≥ 50 years scheduled for cardiac surgery were assessed for preoperative cognitive performance, and functional and physical status. Clinical and biochemical data were systematically recorded perioperatively.

RESULTS

Of the 215 patients remaining for analysis, 31% developed delirium in the intensive care unit. Using logistic regression models, older age [73.3 (71.2-75.4) vs 68.5 (67.0-70.0); P = 0.016], higher Charlson's comorbidity index [3.0 (1.5-4.0) vs 2.0 (1.0-3.0) points; P = 0.009], lower Mini-Mental State Examination (MMSE) score (MMSE, [27 (23-29) vs 28 (27-30) points; P = 0.021], length of cardiopulmonary bypass (CPB) [CPB; 133 (112-163) vs 119 (99-143) min; P = 0.004], and systemic inflammatory response syndrome in the intensive care unit [25 (36.2%) vs 13 (8.9%); P = 0.001] were independently associated with delirium. Combining age, MMSE score, Charlson's comorbidity index, and length of CPB in a regression equation allowed for a prediction of postoperative delirium with a sensitivity of 71.19% and a specificity of 76.26% (receiver operating analysis, area under the curve: 0.791; 95% confidence interval: 0.727-0.845).

CONCLUSIONS

Further research will evaluate if modification of these risk factors prevents delirium and improves outcomes.

Pre-existing cerebral infarcts as a risk factor for delirium after coronary artery bypass graft surgery

OBJECTIVES

Delirium is a common and critical clinical syndrome in older patients. We examined whether abnormalities in the brain that could be assessed by magnetic resonance imaging predisposed patients to develop delirium after coronary artery bypass graft surgery. We also analysed the association between delirium and cognitive dysfunction after coronary artery bypass graft surgery.

METHODS

Data were collected prospectively on 153 patients aged 60 years or older who consecutively underwent elective isolated coronary artery bypass graft surgery. All patients were assessed for prior cerebral infarctions and craniocervical artery stenosis by magnetic resonance imaging (MRI) and angiography of their brains. Atherosclerosis of the ascending aorta was examined by epiaortic ultrasound at the time of surgery. Individual cognitive status was measured using four tests in all the patients before surgery and on the seventh postoperative day. A single psychiatrist diagnosed delirium using the Diagnostic and Statistical Manual of Mental Disorders 4th edition IV criteria.

RESULTS

Postoperative delirium occurred in 16 patients (10.5%). Compared with patients who did not develop postoperative delirium, delirious patients had significantly higher rates of peripheral artery disease, preoperative decline in global cognitive function and pre-existing multiple cerebral infarctions on MRI. In addition, 9 (56%) of the delirious patients suffered postoperative cognitive dysfunction. Stepwise logistic regression analysis found significant independent predictors of postoperative delirium to be preoperative cerebral infarcts on MRI (odds ratio [OR], 2.26; 95% confidence interval [CI] 1.10-4.78), preoperative decline in global cognitive function (OR 4.54; 95% CI 1.21-16.51) and atherosclerosis of the ascending aorta (OR 2.44; 95% CI 1.03-5.62).

CONCLUSIONS

Our findings suggested that postoperative delirium was associated with pre-existing multiple cerebral infarctions on MRI, preoperative decline in global cognitive function and ascending aortic atherosclerosis in elderly patients undergoing coronary artery bypass graft surgery and increased risk of postoperative cognitive dysfunction.

Extending the ABCDE bundle to the post-intensive care unit setting

A recently proposed interprofessional, evidence-based, multicomponent approach to mitigating the effects of intensive care unit (ICU)-acquired delirium and weakness has the potential to radically transform the way care is delivered to older adults requiring sedation, mechanical ventilation, or both. The Awakening and Breathing Coordination, Delirium Monitoring and Management, and Early Mobility (ABCDE) bundle empowers members of the interdisciplinary ICU team to implement the best available evidence regarding mechanical ventilation, sedation, weakness, and delirium in a safe, effective, and patient-centered manner. Considering that critically ill older adults are cared for in a number of different settings during the course of hospitalization and recovery, the purpose of this article is to explore the rationale and possible benefits of extending the ABCDE bundle into the post-ICU setting. We provide a case study that illustrates how ABCDE bundle adoption could be the key to improving the quality of care provided to seriously ill older adults in the ICU and beyond.

Perioperative delirium and its relationship to dementia

A number of serious clinical cognitive syndromes occur following surgery and anesthesia. Postoperative delirium is a behavioral syndrome that occurs in the perioperative period. It is diagnosed through observation and characterized by a fluctuating loss of orientation and confusion. A distinct syndrome that requires formalized neurocognitive testing is frequently referred to as postoperative cognitive dysfunction (POCD). There are serious concerns as to whether either postoperative delirium or postoperative cognitive dysfunction leads to dementia. These concerns are reviewed in this article.

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.

Treatment of delirium following cardiac surgery

Postoperative delirium is a common medical complication following cardiac surgery. This paper will outline the treatment options for delirium with a focus on prophylactic use of risperidone before cardiac surgery.

Cortisol levels and neuropsychiatric diagnosis as markers of postoperative delirium: a prospective cohort study

Introduction

The pathophysiology of delirium after cardiac surgery is largely unknown. The purpose of this study was to investigate whether increased concentration of preoperative and postoperative plasma cortisol predicts the development of delirium after coronary artery bypass graft surgery. A second aim was to assess whether the association between cortisol and delirium is stress related or mediated by other pathologies, such as major depressive disorder (MDD) or cognitive impairment.

Methods

The patients were examined 1 day preoperatively with the Mini International Neuropsychiatric Interview and the Montreal Cognitive Assessment and the Trail Making Test to screen for depression and for cognitive impairment, respectively. Blood samples for cortisol levels were collected both preoperatively and postoperatively. The Confusion Assessment Method for the Intensive Care Unit was used within the first 5 days postoperatively to screen for a diagnosis of delirium.

Results

Postoperative delirium developed in 36% (41 of 113) of participants. Multivariate logistic regression analysis revealed two groups independently associated with an increased risk of developing delirium: those with preoperatively raised cortisol levels; and those with a preoperative diagnosis of MDD associated with raised levels of cortisol postoperatively. According to receiver operating characteristic analysis, the most optimal cutoff values of the preoperative and postoperative cortisol concentration that predict the development of delirium were 353.55 nmol/l and 994.10 nmol/l, respectively.

Conclusion

Raised perioperative plasma cortisol concentrations are associated with delirium after coronary artery bypass graft surgery. This may be an important pathophysiological consideration in the increased risk of postoperative delirium seen in patients with a preoperative diagnosis of MDD.

Can we identify risk factors for postoperative delirium in cardiac coronary patients? Our experience

INTRODUCTION

Delirium is a temporary mental disorder that frequently occurs among elderly hospitalized patients. Patients who undergo cardiac operations have an increased risk of postoperative delirium, which is associated with higher mortality and morbidity rates, a prolonged hospital stay, and reduced cognitive and functional recovery.

PATIENTS AND METHODS

In our prospective study, we included 370 consecutive adult patients who underwent on-pump coronary artery surgery between January 1, 2011, and July 1, 2011. We selected 21 potential risk factors and divided them into preoperative, intraoperative, and postoperative groups. Delirium was diagnosed with the Confusion Assessment Method.

RESULTS

Postoperative delirium was diagnosed in 74 patients (20%). Four predictive factors were associated with postoperative delirium: diabetes mellitus, cerebrovascular disease, peripheral vascular disease, and prolonged intubation (P < .05).

CONCLUSION

Three of the four predictive factors significantly associated with delirium are preoperative. They are relatively easy to measure and can be used to identify patients at higher risk. Fast extubation of these patients and preventive interventions can be taken to prevent negative consequences of this postoperative complication.

The impact of intra- and postoperative albumin levels as a biomarker of delirium after cardiopulmonary bypass: results of an exploratory study

In this prospective study the frequency of delirium after cardiac surgery with cardiopulmonary bypass (CPB) was determined. Furthermore, we investigated the impact of intra- and postoperative levels of albumin as a biomarker of delirium. Thirty-four patients who underwent elective CPB at the Department of Cardiac Surgery, Ludwig-Maximilians-University of Munich, Germany, were enroled in this prospective study. During the intensive care unit (ICU) stay and shortly after discharge from the ICU, delirious state was evaluated daily using the Delirium-Rating-Scale. Albumin was assayed pre-anaesthesia, immediately after induction of anaesthesia, at the beginning of the heart-lung-apparatus period, immediately before the opening and 5min after the opening of the aortic clamp, 24h and 48h postoperatively and on the day before discharge. After CPB, a clinical significant delirious state was observed in 11 patients (32.4%). The albumin level decreased during the surgical intervention and increased postoperatively with a maximum level at the time of discharge. CPB patients with delirious state showed a significantly lower albumin level 24h and 48h postoperatively than those without delirium. A low level of postoperative albumin seems to be a useful biomarker to identify patients with high risk of delirious state after CPB.

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.

Quality of care and analysis of surgical complications

BACKGROUND

During the past years evaluation of quality of care has become an important aspect of transparency of care, and complications is one of these parameters. Therefore, we analyzed the complication rate in an academic hospital over a 6-year period.

METHODS

During the period 2004-2009, all adult surgical patients admitted to and discharged from the Department of Surgery were selected for this time trend study. The Dutch national surgical complication registry was used in the analysis, which registers according to a three-tiered matrix-like classification system. Yearly changes in complication rates were analyzed statistically using the χ(2) for trend test. Subsequently, multivariable regression analysis was used to find significant independent predictors for sustaining a complication.

RESULTS

The mean complication rate per admission rose significantly from 0.18 in 2004 to 0.30 in 2009 (p < 0.001). The largest increase was observed by the following variables: less severe complications, complex surgical procedures, and ASA classification. Delirium, gastoparesis, and ileus were complications showing the largest increase. Age, male gender, ASA, and surgical complexity were found as independent predictors.

CONCLUSIONS

This study showed a significant increase of complications. The increase was mainly due to less severe complications, in particular delirium, ileus, and gastroparesis.

Postoperative Atrial Fibrillation: Year 2011 Review of Predictive and Preventative Factors of Atrial Fibrillation Post Cardiac Surgery

Background: Post cardiac surgery atrial fibrillation is common after cardiac surgery. Despite the advances in medical and surgical treatment, its incidence remains high and unchanged for decades. The aim of this review was to summarize studies published in 2011 on identifying factors, prevention strategies, treatment and effect of post operative atrial fibrillation (POAF) on the outcome after cardiac surgery. Methods: A review was performed on Medline, Embase and Chocrane on all of the English-language, peer-reviewed published clinical studies on POAF; studies investigating the mechanism of developing POAF, prevention, treatment and outcome were all included and analyzed. Case reports, studies on persistent/preoperative atrial fibrillation (AF), POAF after cardiac transplant, congenital cases and nonclinical studies were all excluded. We have also valuated these studies based on the type of the study, their originality, impact factor of the journal and their limitations. Results: Overall 62 studies were reviewed and analyzed; 26 on POAF predictive factors, 31 on preventative strategies and 6 on the outcome of POAF. Of these studies only two were original and the remaining were either performed in AF in general population (n=10) or had been studied and reported several times before in cardiac surgery (n=50). The average impact factor of the journals that POAF was published in was only 2.8 ranging between 0.5 and 14.5. Conclusion: Post cardiac surgery atrial fibrillation is a multi-factorial and complex condition. Cardiac surgery may be a risk factor for developing POAF in patients already susceptible to this condition and may not be a complication of cardiac surgery. Future studies should mainly focus on histological changes in the conductive tissue of atrium and related treatment strategies rather than predictive factors of POAF and more funding should be made available to study this condition from new and entirely different perspectives.

Pharmacological risk factors for delirium after cardiac surgery: a review

PURPOSE

The objective of this review is to evaluate the literature on medications associated with delirium after cardiac surgery and potential prophylactic agents for preventing it.

SOURCE

Articles were searched in MEDLINE, Cumulative Index to Nursing and Allied Health, and EMBASE with the MeSH headings: delirium, cardiac surgical procedures, and risk factors, and the keywords: delirium, cardiac surgery, risk factors, and drugs. Principle inclusion criteria include having patient samples receiving cardiac procedures on cardiopulmonary bypass, and using DSM-IV-TR criteria or a standardized tool for the diagnosis of delirium.

PRINCIPAL FINDINGS

Fifteen studies were reviewed. Two single drugs (intraoperative fentanyl and ketamine), and two classes of drugs (preoperative antipsychotics and postoperative inotropes) were identified in the literature as being independently associated with delirium after cardiac surgery. Another seven classes of drugs (preoperative antihypertensives, anticholinergics, antidepressants, benzodiazepines, opioids, and statins, and postoperative opioids) and three single drugs (intraoperative diazepam, and postoperative dexmedetomidine and rivastigmine) have mixed findings. One drug (risperidone) has been shown to prevent delirium when taken immediately upon awakening from cardiac surgery. None of these findings was replicated in the studies reviewed.

CONCLUSION

These studies have shown that drugs taken perioperatively by cardiac surgery patients need to be considered in delirium risk management strategies. While medications with direct neurological actions are clearly important, this review has shown that specific cardiovascular drugs may also require attention. Future studies that are methodologically consistent are required to further validate these findings and improve their utility.

Preoperative statin therapy is not associated with a decrease in the incidence of delirium after cardiac operations

BACKGROUND

Delirium after cardiac operations is associated with significant morbidity and death. Statins have been recently suggested to exert protective cerebral effects. This study investigated whether preoperative statins were associated with decreased incidence of postoperative delirium in patients undergoing coronary artery bypass grafting.

METHODS

The study enrolled 4,659 consecutive patients (21% women; age, 67.8±9.2 years) undergoing coronary artery bypass grafting. A propensity score-based optimal-matching algorithm was used to match 1,577 patients receiving preoperative statins with a control group (1:1). Patients were screened for delirium in the intensive care unit according to the Confusion Assessment Method for the intensive care unit.

RESULTS

Delirium affected 89 patients (3%), and preoperative statin administration was not multivariably associated with a decreased incidence of delirium (odds ratio, 1.52; 95% confidence interval, 0.97 to 2.37; p=0.18) and was also unrelated to a delirium decrease in patient subgroups undergoing isolated coronary artery bypass grafting (odds ratio, 1.31; 95% confidence interval, 0.68 to 2.52; p=0.51) or combined valvular procedures (odds ratio, 1.72; 95% confidence interval, 0.96 to 3.07, p=0.08). Similar results were observed for age groups and cardiopulmonary bypass durations. Patients affected by postoperative delirium experienced a longer hospital stay (25th to 75th percentile) of 11 (7 to 18 days) vs 7 days (7 to 8 days, p<0.001) and 12% hospital mortality vs 1% (p<0.001).

CONCLUSIONS

Preoperative statins were not associated with a decreased incidence of delirium in patients undergoing coronary revascularization.