The role of future longitudinal studies in ICU survivors: understanding determinants and pathophysiology of brain dysfunction

Abstract

Recent investigations demonstrate that most critical care survivors face significant brain-related morbidity including neurocognitive deficits. While current data on neurocognitive outcomes after critical illness are intriguing, gaps in the literature far exceed what we have learned to date. In this paper, we examine important areas of investigation heretofore unaddressed and propose directions for clinically oriented outcomes research. Neurocognitive impairments after critical illness, which affect multiple cognitive domains, may improve during the first 12 months after ICU discharge but may persist in many patients for years. These impairments appear to be independent of traditional measures of severity of critical illness or age, and risk factors for and mechanisms of injury are currently being defined. Over the last decade, ICU-related cognitive impairment has been identified as a significant public health problem and has become the focus of intense investigation by researchers around the world. While substantial work has been done to date, vitally important questions remain. Future research should evaluate the mechanisms of and risk factors for brain injury, the natural history of neurocognitive dysfunction, structural and functional brain-imaging studies, and therapeutic modalities designed to prevent or decrease neuropsychological disability.