Clinical utility and use of DSM-IV and ICD-10 Criteria and The Memorial Delirium Assessment Scale in establishing a diagnosis of delirium after cardiac surgery

Natural Language Processing CAM Algorithm Improves Delirium Detection Compared With Conventional Methods

Delirium is known to be underdiagnosed and underdocumented. Delirium detection in retrospective studies occurs mostly by clinician diagnosis or nursing documentation. This study aims to assess the effectiveness of natural language processing-confusion assessment method (NLP-CAM) algorithm when compared to conventional modalities of delirium detection. A multicenter retrospective study analyzed 4351 COVID-19 hospitalized patient records to identify delirium occurrence utilizing three different delirium detection modalities namely clinician diagnosis, nursing documentation, and the NLP-CAM algorithm. Delirium detection by any of the 3 methods is considered positive for delirium occurrence as a comparison. NLP-CAM captured 80% of overall delirium, followed by clinician diagnosis at 55%, and nursing flowsheet documentation at 43%. Increase in age, Charlson comorbidity score, and length of hospitalization had increased delirium detection odds regardless of the detection method. Artificial intelligence-based NLP-CAM algorithm, compared to conventional methods, improved delirium detection from electronic health records and holds promise in delirium diagnostics.

Lower Preoperative Verbal Memory Performance Is Associated with Delirium after Coronary Artery Bypass Graft Surgery: A Prospective Cohort Study

OBJECTIVE

Cognitive impairment constitutes one of the major risk factors of delirium after coronary artery bypass graft (CABG) surgery; however, it is unclear whether only patients with global cognitive decline are at increased risk for delirium or if individuals with preserved global cognitive functions but impairments in specific cognitive domains are also more vulnerable to developing delirium. Thus, this study aimed to analyze the neurocognitive status of patients scheduled for CABG surgery with the use of an advanced computerized cognitive battery (CNS Vital Signs) and to investigate possible associations between impaired performance in selective cognitive areas and the risk of postoperative delirium development.

METHODS

The study enrolled 127 participants with a median age of 67 years (IQR: 63-71). Postoperative delirium developed in 32 (25%) patients.Before surgery, the patients were screened for global cognitive impairment with the use of the Mini-Mental State Examination Test, and the individuals were asked to perform the CNS Vital Signs battery to investigate 12 specific cognitive domains. The Confusion Assessment Method and the Memorial Delirium Assessment Scale were used to screen for a diagnosis of delirium postoperatively.

RESULTS

In multivariate models, a lower score of verbal memory-assessed preoperatively was independently associated with the risk of postoperative delirium development. Other independent predictors of delirium included more advanced age, gender female, depression, postoperative pyrexia, and the presence of extracorporeal circulation.

CONCLUSIONS

As decreased verbal memory constitutes an independent risk factor for postoperative delirium, a verbal memory test may be a useful predictor of postoperative delirium development.

Oxidative stress and soluble receptor for advanced glycation end-products play a role in the pathophysiology of delirium after cardiac surgery

Coronary-artery bypass graft (CABG) surgery is known to improve cardiac function and decrease mortality, albeit, this method of treatment is also associated with a neuropsychiatric complications including postoperative delirium. The pathophysiology of delirium after cardiac surgery remains poorly understood. Thus, the purpose of this study was to investigate whether oxidative stress reflected by decreased preoperative and postoperative plasma antioxidant activity is independently associated with delirium after cardiac surgery. The second aim was to assess whether decreased antioxidant activity is stress-related or mediated by other pathologies such as major depressive disorder (MDD), anxiety disorders, and cognitive impairment. Furthermore, the putative relationship between pre- and postoperative soluble receptor for advanced glycation end-products (sRAGE) overexpression and plasma antioxidant capacity was evaluated. The patients cognitive status was assessed 1 day preoperatively with the use of the Mini-Mental State Examination Test and the Clock Drawing Test. A diagnosis of MDD and anxiety disorders was established on the basis of DSM-5 criteria. Blood samples for antioxidant capacity and sRAGE 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. Postoperative delirium was diagnosed in 34% (61 of 177) of individuals. Multivariate logistic regression analysis revealed that low baseline antioxidant capacity was independently associated with postoperative delirium development. Moreover, increased risk of delirium was observed among patients with a preoperative diagnosis of MDD associated with antioxidant capacity decreased postoperatively. According to receiver operating characteristic analysis, the most optimal cutoff values of the preoperative and postoperative antioxidant capacity that predict the development of delirium were 1.72 mM and 1.89 mM, respectively. Pre- and postoperative antioxidant capacity levels were negatively correlated with postoperative sRAGE concentration (Spearman's Rank Correlation − 0.198 and − 0.158, p < 0.05, respectively). Patients with decreased preoperative antioxidant activity and those with depressive episodes complicated with lower postoperative antioxidant activity are at significantly higher risk of delirium after cardiac surgery development. sRAGE overexpression may be considered as protective mechanism against increased oxidative stress and subsequent cell damage.

Effect of atorvastatin on delirium status of patients in the intensive care unit: a randomized controlled trial

INTRODUCTION

Delirium is one of the most prevalent complications in intensive care unit (ICU) patients, which is related to worse clinical outcomes including a longer ICU stay, longer duration of mechanical ventilation, higher mortality rates and increased risk of cognitive impairment. Observational studies have suggested that statins might have a positive effect on delirium status of hospitalized patients. To date, there has been no trial assessing the effect of atorvastatin on delirium status in critically ill patients. Thus, the aim of the current study was to determine the efficacy of atorvastatin on delirium status of patients in the ICU.

METHODS

In this randomized, double-blind and controlled trial, a total of 90 patients in the general ICU who had delirium for at least 2 days were randomly divided into atorvastatin (40 mg/day) (n = 40) and control (n = 50) groups. Delirium status of the patients was determined twice a day at 10:00 a.m. and 18:00 p.m. using the Richmond Agitation-Sedation Scale (RASS).

RESULTS

Administration 40 mg/day of atorvastatin significantly reduced the mean RASS score and increased delirium-free days at both morning and afternoon time points compared to the control group (p < 0.05).

CONCLUSIONS

Administration of atorvastatin had a significant positive effect on delirium status in patients admitted to the ICU.

Symptom profile of alcohol withdrawal delirium: factor analysis of Delirium Rating Scale-Revised-98 version

BACKGROUND

The symptom profile of alcohol withdrawal delirium (AWD), relative to deliriums of other etiology, remains uncertain.

OBJECTIVE

To evaluate the factor structure of symptoms in patients with AWD, as assessed by the Delirium Rating Scale-Revised-98 (DRS-R-98).

METHOD

A total of 112 patients aged 18 years or more with AWD were assessed on DRS-R-98.

RESULTS

The mean age of participants was 44.2 years. About two-third of the patients developed delirium within 24 hours of the last intake of alcohol and the mean duration of delirium at the time of assessment was 3.9 days. In 46% of cases the delirium was attributed solely to alcohol withdrawal; in the remaining subjects alcohol withdrawal was a major contributory factor. Three separate principal component analysis (whole sample, pure AWD and AWD with associated etiologies) were carried out. In all the factor analyses, one of the factors included cognitive symptoms (attention, orientation and visuospatial disturbances) along with or without short- and long-term memory impairment; the second factor included motoric symptoms along with sleep-wake cycle disturbances; the third factor included psychotic symptoms. For the whole group and subgroup of AWD with associated etiologies, items of higher level thinking (i.e. language disturbances and thought process abnormality) loaded along with cognitive symptoms. In pure AWD group, these items along with memory disturbances loaded with psychotic symptoms.

CONCLUSIONS

Results of the current factor analyses suggest that the factor structure of pure AWD is different from AWD with associated etiologies. Hence, attention to the symptom profile of patients with AWD may provide clues to delirium etiology.

Delirium in advanced age and dementia: A prolonged refractory course of delirium and lower functional status

OBJECTIVE

The factors associated with persistent delirium, in contrast to resolved delirium, have not been studied well. The aim of our present study was to identify the factors associated with delirium resolution as measured by the Memorial Delirium Assessment Scale (MDAS) and functional improvement as measured by the Karnofsky Performance Status (KPS) scale.

METHOD

All subjects were recruited from psychiatric referrals at the Memorial Sloan Kettering Cancer Center (MSKCC). The two study instruments were performed at baseline (T1), at 2-3 days (T2), and at 4-7 days (T3). Subjects with persistent delirium were compared to those with resolved delirium in respect to sociodemographic and medical variables.

RESULTS

Overall, 26 out of 111 patients had persistent delirium. These patients were older, predominantly male, and had more frequently preexisting comorbid dementia. Among cancer diagnoses and stage of illness, brain cancer and terminal illness contributed to persistent delirium or late response, whereas gastrointestinal cancer was associated with resolved delirium. Among etiologies, infection responded late to delirium management, usually at one week. Furthermore, delirium was more severe in patients with persistent delirium from baseline through one week. At baseline, MDAS scores were 20.1 in persistent delirium compared to 17 to 18.8 in resolved delirium (T2 and T3), and at one week of management (T3), MDAS scores were 15.2 and 4.7 to 7.4, respectively. At one week of management, persistent delirium manifested in more severe impairment in the domains of consciousness, cognition, organization, perception, psychomotor behavior, and sleep-wake cycle. In addition, persistent delirium caused more severe functional impairment.

SIGNIFICANCE OF RESULTS

In this delirium sample, advanced age and preexisting dementia, as well as brain cancer, terminal illness, infection, and delirium severity contributed to persistent delirium or late response, indicating a prolonged and refractory course of delirium, in addition to more severe functional impairment through one week of management.

A comparison of delirium diagnosis in elderly medical inpatients using the CAM, DRS-R98, DSM-IV and DSM-5 criteria

BACKGROUND

The recently published DSM-5 criteria for delirium may lead to different case identification and rates of delirium than previous classifications. The aims of this study are to determine how the new DSM-5 criteria compare with DSM-IV in identification of delirium in elderly medical inpatients and to investigate the agreement between different methods, using CAM, DRS-R98, DSM-IV, and DSM-5 criteria.

METHODS

Prospective, observational study of elderly patients aged 70+ admitted under the acute medical teams in a regional general hospital. Each participant was assessed within 3 days of admission using the DSM-5, and DSM-IV criteria plus the DRS-R98, and CAM scales.

RESULTS

We assessed 200 patients [mean age 81.1±6.5; 50% female; pre-existing cognitive impairment in 63%]. The prevalence rates of delirium for each diagnostic method were: 13.0% (n = 26) for DSM-5; 19.5% (n = 39) for DSM-IV; 13.5% (n = 27) for DRS-R98 and 17.0%, (n = 34) for CAM. Using tetrachoric correlation coefficients the agreement between DSM-5 and DSM-IV was statistically significant (ρtetr = 0.64, SE = 0.1, p < 0.0001). Similar significant agreement was found between the four methods.

CONCLUSIONS

DSM-IV is the most inclusive diagnostic method for delirium, while DSM-5 is the most restrictive. In addition, these classification systems identify different cases of delirium. This could have clinical, financial, and research implications. However, both classification systems have significant agreement in the identification of the same concept (delirium). Clarity of diagnosis is required for classification but also further research considering the relevance in predicting outcomes can allow for more detailed evaluation of the DSM-5 criteria.

Role of CRP, TNF-a, and IGF-1 in Delirium Pathophysiology

INTRODUCTION

Delirium is a common and life-threatening neuropsychiatric syndrome. Diagnosing delirium can be challenging, which increases mortality and mortality rates and health care costs. The biologic model of delirium is not definite yet, but evidence supports a cholinergic deficiency model. Delirium may be the result of processes and drugs that trespass a compromised blood-brain barrier. We aimed to evaluate the possible diagnostic utilization and the role of certain biomarkers, such as C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), and insulin like growth factor-1 (IGF-1), in delirium etiology.

METHODS

A total of 93 inpatients that planned to undergo cardiovascular surgery were informed; 35 of them completed the study. Medical history and current cognitive status were evaluated pre-operatively. Participants were followed using Delirium Rating Scale-Revised-98 Turkish (DRS-R98-T) for delirium symptoms, and blood samples were collected post-operatively.

RESULTS

Delirium was developed more in participants who had worse pre-operative cognitive status. Also, low pre-operative IGF-1 levels were detected in the delirium group. Pre-operative CRP and TNF-α levels were not different between groups.

CONCLUSION

Low IGF-1 levels can be used to predict delirium after surgery. However, the complex nature of cytokines and delirium itself make it difficult to utilize cytokines to predict delirium instead of psychometric tools.

Delirium diagnosis methodology used in research: a survey-based study

OBJECTIVE

To describe methodology used to diagnose delirium in research studies evaluating delirium detection tools.

METHODS

The authors used a survey to address reference rater methodology for delirium diagnosis, including rater characteristics, sources of patient information, and diagnostic process, completed via web or telephone interview according to respondent preference. Participants were authors of 39 studies included in three recent systematic reviews of delirium detection instruments in hospitalized patients.

RESULTS

Authors from 85% (N = 33) of the 39 eligible studies responded to the survey. The median number of raters per study was 2.5 (interquartile range: 2-3); 79% were physicians. The raters' median duration of clinical experience with delirium diagnosis was 7 years (interquartile range: 4-10), with 5% having no prior clinical experience. Inter-rater reliability was evaluated in 70% of studies. Cognitive tests and delirium detection tools were used in the delirium reference rating process in 61% (N = 21) and 45% (N = 15) of studies, respectively, with 33% (N = 11) using both and 27% (N = 9) using neither. When patients were too drowsy or declined to participate in delirium evaluation, 70% of studies (N = 23) used all available information for delirium diagnosis, whereas 15% excluded such patients.

CONCLUSION

Significant variability exists in reference standard methods for delirium diagnosis in published research. Increasing standardization by documenting inter-rater reliability, using standardized cognitive and delirium detection tools, incorporating diagnostic expert consensus panels, and using all available information in patients declining or unable to participate with formal testing may help advance delirium research by increasing consistency of case detection and improving generalizability of research results.

Concordance between DSM-IV and DSM-5 criteria for delirium diagnosis in a pooled database of 768 prospectively evaluated patients using the delirium rating scale-revised-98

BACKGROUND

The Diagnostic and Statistical Manual fifth edition (DSM-5) provides new criteria for delirium diagnosis. We examined delirium diagnosis using these new criteria compared with the Diagnostic and Statistical Manual fourth edition (DSM-IV) in a large dataset of patients assessed for delirium and related presentations.

METHODS

Patient data (n = 768) from six prospectively collected cohorts, clinically assessed using DSM-IV and the Delirium Rating Scale-Revised-98 (DRS-R98), were pooled. Post hoc application of DRS-R98 item scores were used to rate DSM-5 criteria. 'Strict' and 'relaxed' DSM-5 criteria to ascertain delirium were compared to rates determined by DSM-IV.

RESULTS

Using DSM-IV by clinical assessment, delirium was found in 510/768 patients (66%). Strict DSM-5 criteria categorized 158 as delirious including 155 (30%) with DSM-IV delirium, whereas relaxed DSM-5 criteria identified 466 as delirious, including 455 (89%) diagnosed by DSM-IV (P <0.001). The concordance between the different diagnostic methods was: 53% (ĸ = 0.22) between DSM-IV and the strict DSM-5, 91% (ĸ = 0.82) between the DSM-IV and relaxed DSM-5 criteria and 60% (ĸ = 0.29) between the strict versus relaxed DSM-5 criteria. Only 155 cases were identified as delirium by all three approaches. The 55 (11%) patients with DSM-IV delirium who were not rated as delirious by relaxed criteria had lower mean DRS-R98 total scores than those rated as delirious (13.7 ± 3.9 versus 23.7 ± 6.0; P <0.001). Conversely, mean DRS-R98 score (21.1 ± 6.4) for the 70% not rated as delirious by strict DSM-5 criteria was consistent with suggested cutoff scores for full syndromal delirium. Only 11 cases met DSM-5 criteria that were not deemed to have DSM-IV delirium.

CONCLUSIONS

The concordance between DSM-IV and the new DSM-5 delirium criteria varies considerably depending on the interpretation of criteria. Overly-strict adherence for some new text details in DSM-5 criteria would reduce the number of delirium cases diagnosed; however, a more 'relaxed' approach renders DSM-5 criteria comparable to DSM-IV with minimal impact on their actual application and is thus recommended.

Haloperidol, risperidone, olanzapine and aripiprazole in the management of delirium: A comparison of efficacy, safety, and side effects

OBJECTIVE

The aim of this study was to compare the efficacy and side-effect profile of the typical antipsychotic haloperidol with that of the atypical antipsychotics risperidone, olanzapine, and aripiprazole in the management of delirium.

METHOD

The Memorial Delirium Assessment Scale (MDAS), the Karnofsky Performance Status (KPS) scale, and a side-effect rating were recorded at baseline (T1), after 2-3 days (T2), and after 4-7 days (T3). Some 21 cases were case-matched by age, preexisting dementia, and baseline MDAS scores, and subsequently analyzed.

RESULTS

The baseline characteristics of the medication groups were not different: The mean age of the patients ranged from 64.0 to 69.6 years, dementia was present in between 23.8 and 28.6%, and baseline MDAS scores were 19.9 (haloperidol), 18.6 (risperidone), 19.4 (olanzapine), and 18.0 (aripiprazole). The doses of medication at T3 were 5.5 mg haloperidol, 1.3 mg risperidone, 7.1 mg olanzapine, and 18.3 mg aripiprazole. Over one week, the decline in MDAS scores between medications was equal, and no differences between individual MDAS scores existed at T2 or T3. After one week, the MDAS scores were 6.8 (haloperidol), 7.1 (risperidone), 11.7 (olanzapine), and 8.3 (aripiprazole). At T2, delirium resolution occurred in 42.9-52.4% of cases and at T3 in 61.9-85.7%; no differences in assessments between medications existed. Recorded side effects were extrapyramidal symptoms (EPSs) in haloperidol- and risperidone-managed patients (19 and 4.8%, respectively) and sedation with olanzapine (28.6%).

SIGNIFICANCE OF RESULTS

Haloperidol, risperidone, aripiprazole, and olanzapine were equally effective in the management of delirium; however, they differed in terms of their side-effect profile. Extrapyramidal symptoms were most frequently recorded with haloperidol, and sedation occurred most frequently with olanzapine.

Delirium during psychiatric admission increases mortality in psychiatric patients during and after hospitalization. A nationwide study from 1995 through 2012

OBJECTIVE

Delirium is a common acute neuropsychiatric disorder caused by a variety of physical insults. It is commonly associated with a variety of serious adverse outcomes, including elevated mortality. There are few studies of delirium occurring in psychiatric patients, including its mortality. The aim was to determine the psychiatric diagnostic profile of Danish psychiatric inpatients diagnosed with delirium and to compare standardized mortality ratio (SMR) in this group with the Danish population and general psychiatric inpatients from 1995 through 2012.

METHODS

All first time ICD-10 diagnoses of delirium among psychiatric inpatients were identified in the nationwide Danish Psychiatric Central Research Register (DPCRR) from 1995 through 2012.

RESULTS

A total of 7179 persons diagnosed with delirium were identified in the DPCRR between 1995 and 2012. Of these patients 40.8% had more than one diagnosis of delirium during the period. We identified three distinct groups, based on the first delirium-diagnosis; unspecified delirium (76.9%), comorbid delirium-dementia (19.8%), and drug-related delirium (3.3%). Use of sedative-hypnotics was noted in 46% of those with drug-related delirium. The SMR of delirious psychiatric inpatients compared to all psychiatric inpatients was stable at 1.7 throughout the time period.

CONCLUSION

Delirium occurring in psychiatric inpatients is associated with elevated mortality. Sedative-hypnotic agents are commonly involved in drug-related delirium. Particular preventative effort is warranted for patients with a previous history of delirium, as we found approximately 40% with more than one episode of delirium.

A comparison of the revised Delirium Rating Scale (DRS-R98) and the Memorial Delirium Assessment Scale (MDAS) in a palliative care cohort with DSM-IV delirium

OBJECTIVE

Assessment of delirium is performed with a variety of instruments, making comparisons between studies difficult. A conversion rule between commonly used instruments would aid such comparisons. The present study aimed to compare the revised Delirium Rating Scale (DRS-R98) and Memorial Delirium Assessment Scale (MDAS) in a palliative care population and derive conversion rules between the two scales.

METHOD

Both instruments were employed to assess 77 consecutive patients with DSM-IV delirium, and the measures were repeated at three-day intervals. Conversion rules were derived from the data at initial assessment and tested on subsequent data.

RESULTS

There was substantial overall agreement between the two scales [concordance correlation coefficient (CCC) = 0.70 (CI 95 = 0.60-0.78)] and between most common items (weighted κ ranging from 0.63 to 0.86). Although the two scales overlap considerably, there were some subtle differences with only modest agreement between the attention (weighted κ = 0.42) and thought process (weighted κ = 0.61) items. The conversion rule from total MDAS score to DRS-R98 severity scores demonstrated an almost perfect level of agreement (r = 0.86, CCC = 0.86; CI 95 = 0.79-0.91), similar to the conversion rule from DRS-R98 to MDAS.

SIGNIFICANCE OF RESULTS

Overall, the derived conversion rules demonstrated promising accuracy in this palliative care population, but further testing in other populations is certainly needed.

Comprehensive approaches to managing delirium in patients with advanced cancer

Delirium is a frequently under-recognized complication in patients with advanced cancer. Uncontrolled delirium eventually leads to significant distress to patients and their families. However, delirium episodes can be reversed in half of these patients by eliminating precipitating factors and using appropriate interventions. The purpose of this narrative review is to discuss the most recent updates in the literature on the management of delirium in patients with advanced cancer. This article addresses the epidemiology, cause, pathophysiology, clinical characteristics, and assessment of delirium as well as various treatment options, including nonpharmacologic intervention and palliative sedation.

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.

Treatment characteristics of delirium superimposed on dementia

BACKGROUND

The course of delirium in patients with dementia who are undergoing management of delirium with antipsychotics has not previously been studied. In order to investigate the treatment characteristics of patients with delirium superimposed on dementia in contrast to delirium in the absence of dementia we performed a secondary analysis of our delirium database.

METHODS

We collected sociodemographic data and medical variables in addition to using the systematic rating scales of the Memorial Delirium Assessment Scale (MDAS) and Karnofsky Scale of Performance Status (KPS). These data were recorded in the delirium database. For this analysis we extracted all data pertaining to patients with delirium and dementia (DD) and compared them to those with delirium without dementia (i.e. non-demented with delirium; NDD).

RESULTS

Out of 111 cases with a diagnosis of delirium we acquired 22 cases with a diagnosis of DD and 89 cases with NDD. The mean age was significantly different with 77.1 years for DD and 62.7 years for NDD. The MDAS scores at baseline were significantly higher in DD (21.1) compared to NDD (17.6). Over the course of treatment, MDAS scores were significantly higher in DD with 11.7 at T3 compared with 7.0 in NDD. After three days of management, delirium resolution rates were significantly lower in DD with 18.2% compared to 53.9% in NDD, and at seven days delirium resolution rates were 50% and 83% respectively. At the endpoint of the observation period, DD had a significantly more pronounced disturbance of consciousness and impairment in the cognitive domain. KPS scores were not significantly different between DD and NDD.

CONCLUSION

In our sample of patients with delirium superimposed on dementia the delirium resolution rates were lower than in patients without dementia at one week of treatment. The data suggest that when delirium is superimposed on dementia the delirium may resolve at a slower rate.

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

OBJECTIVE

Delirium after cardiac surgery is a serious complication that results in higher morbidity and mortality rates, and prolongs hospitalisation. However, the knowledge base regarding the issue of postoperative delirium is still limited. Therefore, in the current study, we evaluated the incidence and independent perioperative risk factors of delirium after cardiac surgery.

METHODS

The IPDACS Study recruited 563 consecutive patients undergoing cardiac surgery with cardiopulmonary bypass. The subjects were preoperatively examined by psychiatrists using the Mini-Mental State Examination and the Mini International Neuropsychiatric Interview to assess psychiatric comorbidity. Additionally, other variables connected to the patients' medical condition and surgical and anaesthetic procedures were evaluated. A diagnosis of delirium following surgical intervention was based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria.

RESULTS

The incidence of postoperative delirium according to DSM-IV criteria was 16.3% (95% confidence interval: 13.5-19.6). Multivariate stepwise logistic regression analysis revealed that advanced age, preoperative cognitive impairment, an ongoing episode of major depression, anaemia, atrial fibrillation, prolonged intubation and postoperative hypoxia were independently associated with delirium after cardiac surgery.

CONCLUSION

According to the current analysis, the aforementioned conditions independently predispose to delirium following cardiac surgery. Since some of these factors can be successfully treated and eliminated preoperatively and postoperatively, this study should be helpful in reducing the risk of delirium and in improving the medical care of patients undergoing cardiac surgery (Clinical Trials Identifier: NCT00784576).