Hospital intensivists see it all the time. But they can't explain why months after discharge from critical care units, so many patients lose their ability to think, plan, or make decisions like they did before their admission.
This mysterious, often rapid downward spiral of their mental function increases the chance they will fall, be readmitted, require expensive nursing home care, or other assistance, or have some other poor outcome if they try to live on their own.
Now researchers have not only quantified the frequency of this deterioration, which they say "may be a growing public health problem" because of the number affected. But they also have identified a culprit.
Three months after discharge, four in 10 patients had cognition scores worse than those in people with moderate traumatic brain injury, and one year after discharge, explains Pratik Pandharipande, MD, lead author and critical care specialist at Vanderbilt University Medical Center.
The paper is published in Thursday's New England Journal of Medicine. Both medical and surgical intensive care unit patients were studied.
After one year, "51% of survivors had cognitive impairments 1.5 standard deviations below their age and education-level adjusted mean scores," he says.