Post-intensive care cognitive impairment: questions in mind?

Excerpt

Each year millions of individuals are admitted and treated in intensive care units (ICUs) [1]. Better care has resulted in reduced mortality with a concomitant increase in ICU survivors, many of whom are left with significant morbidities. Large numbers of ICU survivors have cognitive impairments [2]; these impairments are new [3, 4], affect multiple cognitive domains, and are likely permanent. In this issue of Intensive Care Medicine, Wolters et al. [5] systematically review studies that assess cognitive impairment following critical illness. Quality was ascertained based on: (1) systematic baseline assessment of cognitive function (prospective or retrospective), (2) validated follow-up cognitive tests, (3) clear inclusion and exclusion criteria, and (4) adjustment for confounders such as age and gender. Studies had to evaluate patients more than 2 months after ICU discharge; cardiac surgery patients, case reports, reviews and data from animal studies were excluded. Cognitive impairment tests varied greatly, as did the rate of cognitive impairment, its definition, and time to follow-up (2 months to 13 years). The rate of cognitive impairment was <10 % in three of the five studies that used questionnaires or screening test-based cognition assessments; studies that used gold-standard neuropsychological tests found 45 to 80 % of patients had moderate to severe cognitive impairment at follow-up. Loss to follow-up and study duration varied. In ten of the studies the mean age was 54 years or less at study enrollment. While this review highlights important findings regarding post-ICU cognitive impairment, questions remain regarding mechanisms, risk factors, patients' baseline cognitive function, recovery and effect of rehabilitation, and the relationship of cognitive impairments with quality of life and functional abilities. …