Can we predict a delirium after cardiac surgery? A validation study of a delirium risk checklist.

BACKGROUND: Delirium is a common temporary mental disorder that often occurs in patients who undergo cardiac surgery. It is important to prevent the negative side effects of delirium by identifying high-risk patients before surgery. Koster and colleagues designed a risk model to identify patients with an increased risk of postoperative delirium after cardiac surgery. AIM: The aim of this study was to validate the risk model for delirium and further improve the risk model. METHODS: A delirium risk checklist containing predictors associated with postoperative delirium was used during the preoperative outpatient screening in 329 patients. The delirium observation screening scale was used preoperatively and postoperatively to assess delirium. RESULTS: Compared with the model of Koster and colleagues age greater than 70 years and a history of delirium were confirmed as statistically significant predictors of postoperative delirium, while cognitive impairment and alcohol abuse were almost significant factors. The European system for cardiac operative risk evaluation (EuroSCORE), comorbidity and type of surgery could not predict a postoperative delirium again. The area under the curve of this model was 0.79 (95% confidence interval (CI) 0.73-0.86; P<0.001). Based on the data of this study the model was improved with the following independent predictors of postoperative delirium: age, more than one comorbidity, history of delirium and a lower standardised mini mental state examination score as with an area under the curve of 0.79 (95% CI 0.73-0.85; P<0.001). CONCLUSION: The risk model could not be fully validated. It is difficult to validate a risk model over time; there are different circumstances such as the increased focus on the prevention of delirium.

A European Multicenter Study of 616 Patients Receiving the Freedom Solo Stentless Bioprosthesis.

BACKGROUND: The purpose of this study was to evaluate the safety and performance of the Freedom Solo valve in aortic valve replacement by clinical and hemodynamic outcomes. METHODS: Six hundred sixteen patients underwent aortic valve replacement in 18 European centers; mean age was 74.5 ± 5.9 years, 54.1% of the patients were male, and concomitant procedures were performed in 43.2% of the patients. The majority (69%) of the implanted sizes were 23 mm and 25 mm. RESULTS: At 1 year, overall survival was 94.0%, whereas freedom from valve-related death was 98.6%. There were 9 (1.5%) early (≤ 30 days) and 27 (4.4%) late (>30 days) deaths. Early and late valve-related mortality was 0.3% (n = 2) and 1.1% (n = 7), respectively. Freedom from explant was 97.6%; 10 valves were explanted for endocarditis and 4 for paravalvular leak. There were 10 (1.6%) early and 5 (0.8%) late strokes. Atrioventricular block requiring pacemaker implant occurred in 8 (1.3%) and 1 (0.2%) patients in the early and late postoperative period, respectively. Thrombocytopenia was seen in 27 cases (4.4%) in the early postoperative period. Preoperatively, 93.8% of patients were in New York Heart Association functional classes II through IV, whereas at 1 year 96.9% of patients were in New York Heart Association functional classes I and II. At 1-year follow-up, mean and peak pressure gradients were 7.2 and 14.6 mm Hg, respectively. Indexed left ventricular mass decreased by 12% from 138 g/m(2) at discharge to 122 g/m(2) at 1 year. CONCLUSIONS: At 1-year follow-up after Freedom Solo implantation, we found acceptable clinical results with low mortality and morbidity and good hemodynamic performance, confirming safety and effectiveness in this multicenter experience.

Prediction of delirium after cardiac surgery and the use of a risk checklist.

BACKGROUND: Delirium is a temporary mental disorder, which occurs frequently among patients who undergo cardiac surgery. Delirium prediction and its associated prevention is essential. In a previous study, a risk checklist for delirium was developed. AIMS: The present study validated this checklist in a new, larger study population, and also investigated new risk factors. METHODS: Risk factors were obtained during the preoperative outpatient screening in 300 patients who underwent elective cardiac surgery. The Delirium Observation Screening scale was utilized pre- and postoperatively to assess delirium. RESULTS AND CONCLUSION: The incidence of delirium was 17.3%. A higher Euroscore, but not a disturbance in electrolytes, was confirmed as a predictor of postoperative delirium. Based on this study, a new risk model was constructed with the following risk factors: a higher Euroscore, older age (≥70 years), cognitive impairment, number of comorbidities, history of delirium, alcohol use and type of surgery. When using a probability of delirium of 20%, as predicted by the model, the sensitivity was 80.8% and the specificity 82.2%. The area under the curve was 0.89. With the revised delirium risk checklist, including seven new risk factors, patients with an increased risk of developing delirium following cardiac surgery could be identified more accurately.

Consequences of delirium after cardiac operations.

BACKGROUND: Delirium is a transient mental syndrome characterized by disturbances in consciousness, cognition, and perception. The risk that delirium will develop is increased in patients who undergo cardiac operations, especially the elderly. Generally, delirium during hospital admission is independently associated with many negative consequences, such as higher mortality, increased length of hospital stay, nursing home placement after admission, and cognitive and functional decline. METHODS: This prospective follow-up study used the Short Form 36-Item questionnaire, the Cognitive Failure Questionnaire, and a purpose-designed questionnaire to assess 300 patients who underwent elective cardiac operations at 6 months after the procedure. Postoperative delirium developed in 52 patients (17%). Mortality and readmission were also assessed. RESULTS: Delirium after cardiac procedures is associated with increased mortality (13.5% vs 2.0% in patients without), more hospital readmissions (45.7% vs 26.5%), and reduced quality of life. It is also associated with reduced cognitive functioning, including failures in attention, memory, perception, and motor function, and with functional dysfunction such as independency in activities of daily living and mobility. CONCLUSIONS: Postoperative delirium after cardiac operations is associated with many important consequences. These findings provide justification for intervention studies to evaluate whether delirium prevention, early recognition, or treatment strategies might improve postoperative functional and cognitive function.

Risk factors of delirium after cardiac surgery: a systematic review.

BACKGROUND: Delirium or acute confusion is a temporary mental disorder that occurs frequently among hospitalized elderly patients, but also in younger patients a delirium can develop. Patients who undergo cardiac surgery have an increased risk of developing delirium that is associated with many negative consequences. Therefore, prevention of delirium is essential. Despite the high incidence of delirium, a paucity of data on risk factors for delirium exists. AIM: The aim of this study was to summarize the available information concerning these risk factors. METHODS: A literature research was performed using the PubMed, Cinahl, and Cochrane Library databases and was limited to the last 10 years. RESULTS: Our review revealed 27 risk factors; 12 predisposing and 15 precipitating factors for delirium after cardiac surgery. The most established predisposing risk factors were atrial fibrillation, cognitive impairment, depression, history of stroke, older age, and peripheral vascular disease. The most established precipitating risk factor was a red blood cell transfusion. An abnormal albumin level was reported as the most established precipitating risk factor among blood values tested. A low cardiac output and the use of an Intra Aortic Balloon Pump or inotropic medication seem to be the most relevant risk factors associated with a postoperative delirium. CONCLUSION: A multifactorial risk model should be applied to identify patients at an increased risk of developing delirium following elective cardiac surgery. In these patients, if possible, preventative interventions can be taken and early recognition of delirium can be realized. This could potentially decrease the incidence of delirium and negative consequences caused by a postoperative delirium.

The long-term cognitive and functional outcomes of postoperative delirium after cardiac surgery.

BACKGROUND: Delirium or acute confusion is a temporary mental disorder, which occurs frequently among hospitalized elderly patients. Patients who undergo cardiac surgery have an increased risk of developing delirium. This is associated with many negative consequences such as prolonged hospital stay, nursing home placement, and reduced cognitive and functional recovery. METHODS: In this prospective follow-up study, a questionnaire was used 1 to 1.5 years after cardiac surgery in our earlier cohort of 112 patients who underwent elective cardiac surgery, of which 24 patients (21%) developed postoperative delirium as diagnosed by a single psychiatrist. RESULTS: Postoperative delirium after cardiac surgery may be associated with increased mortality (12.5% in patients with delirium versus 4.5% in patients without delirium; p = 0.16), more readmissions to the hospital (47.6% vs 32.6%; p = 0.19), dysfunction in memory (31.6% vs 22.6%; p = 0.39), and concentration problems (36.8% vs 20.2%; p = 0.13); and is associated with sleep disturbance (47.4% vs 23.8%; p = 0.03). CONCLUSIONS: Postoperative delirium after cardiac surgery may be associated with increased mortality and readmissions to the hospital, as well as poorer cognitive and functional outcomes. Therefore, prevention and (or) early recognition of delirium must be improved. In addition, patients and caregivers (family and general practitioner) must be better informed about the long-term consequences of delirium and what they can do about it.

The delirium observation screening scale recognizes delirium early after cardiac surgery.

BACKGROUND: Delirium or acute confusion is a temporary mental disorder which occurs frequently among hospitalized elderly patients. Patients who undergo cardiac surgery have an increased risk of developing delirium. Prevention or early recognition of delirium is essential. The Delirium Observation Screening (DOS) scale was developed to facilitate early recognition of delirium by nurses' observations during routine clinical care. AIM: The aim of this study was to validate the DOS scale in accordance with the diagnosis of the psychiatrist, using the DSM-IV criteria as the gold standard. METHODS: In this observational study, the DOS scale was used to assess whether 112 patients who underwent elective cardiac surgery had developed a postoperative delirium. The psychiatrist was consulted to confirm or refute the diagnosis delirium. Wilcoxon's Rank Sum Test was utilized to compare patients with and without delirium on duration of hospital stay. A Receiver Operating Characteristic Curve of the DOS scale was constructed with accompanying Area Under the Curve (AUC). RESULTS: Based on the diagnosis of the psychiatrist, the incidence of delirium following cardiac surgery was 21.4% and the mean duration of delirium was two and a half days. The time to discharge was 11 days longer in patients with delirium. In 27 of the 112 patients a DOS score of >or=3 was found, that indicates delirium. The sensitivity and specificity of the DOS scale was 100% and 96.6% respectively. The AUC was 0.98. CONCLUSION: The DOS scale is a very good instrument to facilitate early recognition of delirium by nurses' observation of patients who undergo cardiac surgery. Early recognition will expedite good postoperative management such as implementation of appropriate interventions, and may decrease negative consequences caused by postoperative delirium.

Delirium after cardiac surgery and predictive validity of a risk checklist.

BACKGROUND: Delirium or acute confusion is a temporary mental disorder that occurs frequently among hospitalized elderly patients. Patients who undergo cardiac surgery have an increased risk of delirium, which is associated with many negative consequences. Therefore, prevention or early recognition of delirium is essential. METHODS: In this observational study, a risk checklist for delirium was used during the preoperative outpatient screening in 112 patients who underwent elective cardiac surgery. The Delirium Observation Screening (DOS) scale was used before and after surgery to assess whether delirium had developed in patients. The psychiatrist was consulted to confirm or refute the diagnosis delirium. RESULTS: The incidence of delirium after cardiac surgery was 21%, and the mean duration of delirium was 2.5 days. The time to discharge was 11 days longer for patients with delirium. The delirium risk checklist could accurately predict postoperative delirium in patients who underwent elective cardiac surgery based on a disturbance in the electrolytes sodium and potassium and on EuroSCORE (European System for Cardiac Operative Risk Evaluation). When using a probability of delirium of 50%, the sensitivity of the risk checklist was 25.0% and specificity was 95.5%. The predictive value of a positive test was 60.0%, and the predictive value of a negative test was 82.4%. The area under the receiver-operating characteristic curve was 0.75. CONCLUSIONS: With the risk checklist for delirium, patients at an increased risk of delirium after elective cardiac surgery can be identified.