Intensive care delirium is the presentation of the general picture of delirium in the specific setting of the intensive care unit with a patient encountering an acute confusional state, knowing a fluctuating course with periods of inattentions, an altered level of consciousness and disorganised thinking. The onset of delirium is induced by a physical cause stimulated by predisposing and precipitating factors. For the typical clinical situation of the intensive care patient, there will always be a high vulnerability because of severe illness or trauma at the time of admittance. Consequently, an intensive care patient encounters a cascade of predisposing and precipitating risk factors entering the intensive care unit. Despite the existence of validated instruments, the syndrome remains unrecognized by in three out of four delirious patients. Nurses and clinicians might fail to recognize symptoms because of the lack of appropriate tools and knowledge on the subject. The necessity to screen patients sustained by a poor outcome for delirium. Yet, the studied outcome was mainly limited to the intensive care unit or the hospital. Few data are available on long term outcome. This thesis aimed to describe the incidence of intensive care delirium in a Flemish adult population. Consequently, patients were included in a long term follow up study on the outcome of delirium. Additionally, risk factors, including those from the environment, were studied to suggest interventions to lower the incidence of delirium in the intensive care unit.
Delirium in the intensive care unit is known to be associated with worse outcomes. Cognitive impairment, a longer stay in the hospital or in the intensive care unit and a raised mortality have been reported. This research studied the long term outcome after intensive care delirium defined as mortality and quality of life at three and six months after discharge of the intensive care unit. Compared to the non-delirious patients, more delirious patients died. All SF-20 quality of life scores showed lower results for the delirious patients compared to the non-delirious patients. Evidence is growing that delirium may not be fully reversible in all patients. Risk factors for delirium in the intensive care unit were studied. First, a systematic review identified four predisposing and 21 precipitating factors. Consequently, a prospective study included newly admitted adult patients in a multicenter study. The overall delirium incidence was 30 %. Risk factors covered four domains: patient characteristics, chronic pathology, acute illness and environmental factors. Particularly risk factors related to the acute illness and the environment are suitable for preventive action. Predisposing patient characteristics and chronic pathology make the intensive care patient vulnerable at admittance. Sound in the intensive care unit has been a subject of research for years. Although the impact on sleep has been studied, contradicting results require the study of the direct impact of sound on the patient’s outcome. The assessment of sleep remains a problem in the intensive care unit. This study assessed different sound levels and the sound level changes in the intensive care unit and related them to the onset of delirium. All registered sound levels were over the WHO maximum limit of 40 decibels. During the night, the same sound levels were registered, but a lower amount of sound changes was observed than during the day. The 27 % audible sound changes during the night in the university hospital were related to the onset of delirium (p=0.05). A higher amount of alarms in the private hospital was also related to delirium (p=0.008). This research pointed to a possible relation between the amount of alarms and sound changes during the night and the onset of delirium.
Before the start of this research project, delirium was no issue in any of the included intensive care units. During the study, nurses and physicians became more alert for the syndrome. The intensive care staff is now aware of the syndrome and seems motivated for further research. The NEECHAM was accepted as the standard screening tool in the included intensive care units. This research showed the tip of the iceberg of delirium in the intensive care unit. The incidence showed to be high in the Antwerp region. Intensive care nurses and physicians play a key role in an early identification and prevention of the syndrome. This research project identified several modifiable risk factors. Although knowledge on the subject has grown for the past years, several questions remain unanswered. The high incidence of the syndrome might not be tackled for the moment. As long as adequate treatments, preventive actions and revalidation programs are lacking, the patient remains vulnerable for cognitive decline after admittance to the intensive care unit.