Multinational development and validation of an early prediction model for delirium in ICU patients.

RATIONALE: Delirium incidence in intensive care unit (ICU) patients is high and associated with poor outcome. Identification of high-risk patients may facilitate its prevention. PURPOSE: To develop and validate a model based on data available at ICU admission to predict delirium development during a patient's complete ICU stay and to determine the predictive value of this model in relation to the time of delirium development. METHODS: Prospective cohort study in 13 ICUs from seven countries. Multiple logistic regression analysis was used to develop the early prediction (E-PRE-DELIRIC) model on data of the first two-thirds and validated on data of the last one-third of the patients from every participating ICU. RESULTS: In total, 2914 patients were included. Delirium incidence was 23.6%. The E-PRE-DELIRIC model consists of nine predictors assessed at ICU admission: age, history of cognitive impairment, history of alcohol abuse, blood urea nitrogen, admission category, urgent admission, mean arterial blood pressure, use of corticosteroids, and respiratory failure. The area under the receiver operating characteristic curve (AUROC) was 0.76 [95% confidence interval (CI) 0.73-0.77] in the development dataset and 0.75 (95% CI 0.71-0.79) in the validation dataset. The model was well calibrated. AUROC increased from 0.70 (95% CI 0.67-0.74), for delirium that developed <2 days, to 0.81 (95% CI 0.78-0.84), for delirium that developed >6 days. CONCLUSION: Patients' delirium risk for the complete ICU length of stay can be predicted at admission using the E-PRE-DELIRIC model, allowing early preventive interventions aimed to reduce incidence and severity of ICU delirium.

Recalibration of the delirium prediction model for ICU patients (PRE-DELIRIC): a multinational observational study.

PURPOSE: Recalibration and determining discriminative power, internationally, of the existing delirium prediction model (PRE-DELIRIC) for intensive care patients. METHODS: A prospective multicenter cohort study was performed in eight intensive care units (ICUs) in six countries. The ten predictors (age, APACHE-II, urgent and admission category, infection, coma, sedation, morphine use, urea level, metabolic acidosis) were collected within 24 h after ICU admission. The confusion assessment method for the intensive care unit (CAM-ICU) was used to identify ICU delirium. CAM-ICU screening compliance and inter-rater reliability measurements were used to secure the quality of the data. RESULTS: A total of 2,852 adult ICU patients were screened of which 1,824 (64%) were eligible for the study. Main reasons for exclusion were length of stay <1 day (19.1%) and sustained coma (4.1%). CAM-ICU compliance was mean (SD) 82 ± 16% and inter-rater reliability 0.87 ± 0.17. The median delirium incidence was 22.5% (IQR 12.8-36.6%). Although the incidence of all ten predictors differed significantly between centers, the area under the receiver operating characteristic (AUROC) curve of the eight participating centers remained good: 0.77 (95% CI 0.74-0.79). The linear predictor and intercept of the prediction rule were adjusted and resulted in improved re-calibration of the PRE-DELIRIC model. CONCLUSIONS: In this multinational study, we recalibrated the PRE-DELIRIC model. Despite differences in the incidence of predictors between the centers in the different countries, the performance of the PRE-DELIRIC-model remained good. Following validation of the PRE-DELIRIC model, it may facilitate implementation of strategies to prevent delirium and aid improvements in delirium management of ICU patients.

Gastrointestinal perfusion in septic shock.

Septic shock is characterised by vasodilation, myocardial depression and impaired microcirculatory blood flow, resulting in redistribution of regional blood flow. Animal and human studies have shown that gastrointestinal mucosal blood flow is impaired in septic shock. This is consistent with abnormalities found in many other microcirculatory vascular beds. Gastrointestinal mucosal microcirculatory perfusion deficits have been associated with gut injury and a decrease in gut barrier function, possibly causing augmentation of systemic inflammation and distant organ dysfunction. A range of techniques have been developed and used to quantify these gastrointestinal perfusion abnormalities. The following techniques have been used to study gastrointestinal perfusion in humans: tonometry, laser Doppler flowmetry, reflectance spectrophotometry, near-infrared spectroscopy, orthogonal polarisation spectral imaging, indocyanine green clearance, hepatic vein catheterisation and measurements of plasma D-lactate. Although these methods share the ability to predict outcome in septic shock patients, it is important to emphasise that the measurement results are not interchangeable. Different techniques measure different elements of gastrointestinal perfusion. Gastric tonometry is currently the most widely used technique because of its non-invasiveness and ease of use. Despite all the recent advances, the usefulness of gastrointestinal perfusion parameters in clinical decision-making is still limited. Treatment strategies specifically aimed at improving gastrointestinal perfuision have failed to actually correct mucosal perfusion abnormalities and hence not shown to improve important clinical endpoints. Current and future treatment strategies for septic shock should be tested for their effects on gastrointestinal perfusion; to further clarify its exact role in patient management, and to prevent therapies detrimental to gastrointestinal perfusion being implemented.