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13-02-2012 | Cardiology | Article

PRE-DELIRIC model warns of delirium in intensive care


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MedWire News: Dutch researchers have developed a model that predicts delirium in adult patients in intensive care.

"Our PRE-DELIRIC [PREdiction of DELIRium in ICu patients] model reliably predicted the development of delirium for the complete length of stay in intensive care, on the basis of 10 readily available risk factors within 24 hours of admission to intensive care," say Mark van den Boogaard (Radboud University Nijmegen Medical Centre) and colleagues.

The 10 risk factors in the model are age, APACHE (acute physiology and chronic health evaluation)-II score, admission category (surgical, medical, trauma, or neurology/neurosurgery), coma, infection, metabolic acidosis, use of sedatives and morphine, urea concentration, and urgent admission.

These were derived from 1613 intensive care patients from one hospital, 25.5% of whom developed delirium. "Dementia and alcohol misuse are not included [in] the model, as these patients need to be considered as high-risk patients irrespective of the presence of other risk factors," the team writes in the BMJ.

In the derivation cohort, the model was 87% accurate for distinguishing between patients who did and did not develop delirium, whereas the predictions of doctors and nurses attending a subgroup of 124 patients were just 59% accurate.

The team validated the model in a further 549 patients from the same hospital, finding that it had an accuracy of 89%. External validation in an additional 894 patients from four other hospitals gave an accuracy of 84%.

The researchers divided the patients into risk categories based on their PRE-DELIRIC scores: low risk (0 to 20%), moderate risk (>20 to 40%), high risk (>40 to 60%), and very high risk (>60%). The positive likelihood ratios for delirium in patients in these four categories were 3.19, 5.54, 8.57, and 13.00, respectively.

The sensitivity for delirium ranged from 30.0% for a very-high-risk score to 80.7% for a low-risk score. The corresponding specificities were 97.9% and 74.4%.

"Our study shows that the use of the PRE-DELIRIC model is significantly better than the predictions of the attending caregivers, and it should therefore be used daily in intensive care practice," say van den Boogaard et al.

They add that use of the model will "facilitate targeted initiation of preventive measures," such as improvement of orientation, cognitive stimulation, early mobilization, and use of prophylactic drugs.

"The optimal cut-off point of the PRE-DELIRIC model and the most effective delirium preventive interventions for intensive care patients need to be studied in the near future," say the researchers.

They have made an automatic version of the model available on the Radboud University Nijmegen Medical Centre website.

By Eleanor McDermid

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