Delirium in cardiac surgery

Abstract

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. Delirium is associated with many negative consequences. Therefore, prevention or early recognition of delirium is essential. - MAIN AIMS:  Measure incidence delirium and duration of delirium episode after cardiac surgery  examine the predictive validity of the Delirium Observation Screening (DOS) scale  develop and validate the predictive validity of a risk model for delirium  study the consequences of delirium 6 and 12-18 months after cardiac surgery METHODS: In two studies we first developed and then validated a risk model delrium to see wich risk factors are independently associated with a postoperative delirium after cardiac surgery. The diagnosis delirium was based on the DOS scale and the diagnosis was confirmed or refuted by a psychaitrist. To study the consequences of delrium two questionnaire studies were performed in a first cohort with 112 patients and a second cohort with 300 patients. - RESULTS: The incidence delirium after cardiac surgery was 21% and 17% in the two studies. After multivariate analysis a risk model delirium in cardiac surgery patients was constructed with the following risk factors: Euroscore, older age (> 70 years), cognitive impairment, the number of co-morbidities, history of delirium, alcohol use, and type of surgery. The DOS scale is a very good instrument to facilitate early recognition of delirium by nurses’ observation of patients who undergo cardiac surgery. A delirium after cardiac surgery is associated with important consequences: increased mortality, more re-admissions to the hospital, reduced quality of life, and reduced functional and cognitive function. - CONCLUSIONS: With the risk model delirium, including seven risk factors, patients with an increased risk of developing delirium following cardiac surgery can be identified. Next, with the DOS scale early recogniton of delirium can be realized. In further research in patients at risk for delirium, interventions to reduce the number, severity or duration of episodes of delirium, should be investigated.