Delirium and long term cognition in critically ill patients

Abstract

Delirium, a form of acute brain dysfunction, is very common in the critically ill adult patient population. Although its pathophysiology is poorly understood, multiple factors associated with delirium have been identified, many of which are coincident with critical illness. To date, no drug or non-drug treatments have been shown to improve outcomes in patients with delirium. Clinical trials have provided a limited understanding of the contributions of multiple triggers and processes of intensive care unit (ICU) acquired delirium, making identification of therapies difficult. Delirium is independently associated with poor long term outcomes, including persistent cognitive impairment. A longer duration of delirium is associated with worse long term cognition after adjustment for age, education, pre-existing cognitive function, severity of illness, and exposure to sedatives. Interestingly, differences in prevalence are seen between ICU survivor populations, with survivors of acute respiratory distress syndrome experiencing higher rates of cognitive impairment at early follow-up compared with mixed ICU survivor populations. Although cognitive performance improves over time for some ICU survivors, impairment is persistent in others. Studies have so far been unable to identify patients at higher risk of long term cognitive impairment; this is an active area of scientific investigation.

Long-term cognitive functioning is impaired in ICU-treated COVID-19 patients: a comprehensive controlled neuropsychological study

“…Delirium is associated with increased mortality both in the general ICU population and in COVID-19 patients [36,39], and our cohort only included those who survived to six-month follow-up, which might explain the difference in delirium incidence. Delirium is also an independent predictor of long-term cognitive impairment [36,[40][41][42]. During critical illness, pre-existing cognitive impairment predisposes a person to delirium; it is unclear whether this finding partly explains the correlation between delirium during ICU treatment and post-ICU cognitive impairment [43].…”

Prevalence of post-intensive care syndrome in mechanically ventilated patients with COVID-19

“…The prevalence of delirium in ICU patients is estimated between 32 and 87%, although these figures vary considerably depending on whether the studied population had received MV 39 . All patients in our study underwent MV, and due to excessive workload during the pandemic, delirium and PICS prevention measures were inapplicable 40 , 41 .…”

“…Unlike prepandemic studies, hyperactive delirium is much more frequent than hypoactive delirium in COVID-19 patients 42 . Nevertheless, the hypothesis about a possible neuro-invasive potential of SARS-CoV-2 45 and its influence on mental or psychiatric disorders remains open, since to date, its pathophysiology is poorly understood 39 .…”

The obesity paradox for survivors of critically ill patients

“…Survivors of critically ill patients are at risk of experiencing significant physical, cognitive, and mental health issues, which were associated with an increased mortality following discharge from intensive care unit (ICU) [1][2][3][4]. However, factors associated with mortality for survivors of critical illness are not well understood, which may be important when counseling patients and families.…”