Brain dysfunction in critical care patients

Abstract

Risk factors for delirium were studied, an overview of long-term cognitive impairment and mental health problems after ICU stay was given, and the association between intensive care unit (ICU) delirium and long-term cognitive impairment, as well as mental health problems, was explored. In part I of the thesis, we searched for etiological risk factors for delirium during critical illness. Psychopathology prior to hospital admission did increase the risk of developing a delirium during critical illness. No association between exposure to anticholinergic medication and delirium could be demonstrated, neither a significant effect of age or inflammation on this association was present. Yet, age and the presence of inflammation were both individually independent risk factors for transitioning to delirium. Subsequently, no association between corticosteroid exposure and the occurrence of delirium could be demonstrated. Part II of the thesis assessed the occurrence of long-term brain dysfunction after critical illness and evaluated the association with ICU delirium and this long-term dysfunction. A systematic review showed that a substantial number of patients experience cognitive problems after critical illness, although a wide range was reported (4–62%) and follow-up duration was diverse (2–156 months). Elaborating on these cognitive problems after ICU stay, we evaluated the association with delirium during ICU stay. An association between (multiple days of) ICU delirium and long-term self-reported cognitive problems was found in one year ICU survivors. Since systemic inflammation is both a risk factor for delirium during ICU stay, and for long-term cognitive problems, a mediation analysis was conducted to explore the potential mediating effect of exposure to systemic inflammation in the association between ICU delirium and long-term cognitive problems. No mediating effect was found, suggesting that the effect of ICU delirium on long-term cognitive problems was not merely driven by the exposure to systemic inflammation. Additionally whether delirium was associated with long-term mortality and worse health-related quality of life (HRQoL) was evaluated. After adjustment for confounding, the association between ICU delirium and these outcomes did not remain, which showed that ICU delirium itself might not be etiologically related to these long-term outcomes. The occurrence of symptoms of the postintensive care syndrome, with a focus on symptoms of anxiety, depression, and posttraumatic stress disorder (PTSD), three months after critical illness in patients and their families visiting an outpatient clinic was described. A substantial number of family members of former ICU patients seem to have mental health problems. Also a lot of former ICU patients experience mental health problems, three months after ICU discharge. The association between delirium during ICU stay and symptoms of anxiety, depression and PTSD was assessed one year after ICU stay. High frequencies of symptoms of anxiety, depression and PTSD in former ICU patients were demonstrated, even one year after ICU discharge. However, no association between ICU delirium and an increased risk for symptoms of anxiety, depression or PTSD after one year was demonstrated.