Cognitive Impairment Following ICU Hospitalization

Recent research has demonstrated the presence of cognitive impairment in many patients following Intensive Care Unit (ICU) long-term care. Although estimates differ, it appears that at least 1 in 3 survivors of critical illness will experience long-term cognitive impairment of a severity consistent with mild to moderate dementia. Among specific populations, such as patients with Acute Respiratory Distress Syndrome (ARDS), the prevalence of cognitive dysfunction is even greater and may be as high as 80%.

The acquired cognitive deficits reported by ICU survivors vary in nature and include difficulties in areas of attention/concentration, executive functioning (planning/organizing), memory (short-term, verbal, and visual), processing speed, and visuo-spatial construction. As an example please see (currently pending copyright approval) the PDF of a figure which includes drawings from patients 6 months after ICU stay. Deficits in these areas can have significant “real world” consequences such as problems returning to work, balancing a checkbook, finding a parked car, or even following a simple recipe. Future research is needed to more fully determine the causes, but investigators believe that cognitive impairment in ICU survivors may be related to a host of factors such as delirium, hypoxemia, advanced age, low education, inflammatory and coagulopathic derangements incurred during disease such as severe sepsis or the toxic effects of large amounts of sedative and analgesic medications on the brain.

Rates of mental health diseases such as depression and post-traumatic stress disorder (PTSD) are also disturbingly high in patients following critical illness. Clinically significant depression may occur in as many as 30% of ICU survivors, while between 15 and 40% of these patients experience symptoms of PTSD. The existence of such psychiatric syndromes, particularly when combined with cognitive impairment, typically results in a diminished quality of life.