Intensive-Care Units Pose Long-Term Brain Risk, Study Finds
Critically ill patients who survive a stay
in an intensive-care unit, where they are often heavily sedated and
ventilated, can find themselves mentally impaired long after
release. A new study says the problem is far more common and
lasting than previously believed.
Nearly 80% of patients with prolonged ICU stays showed cognitive
problems a year or more later, and more than half exhibited effects
similar to Alzheimer's disease and traumatic brain injury,
according to a report Wednesday in the New England Journal of
The researchers, at Vanderbilt University in Nashville, Tenn., and
the Tennessee Valley Veterans Affairs Geriatric Research Education
and Clinical Center, said the findings highlight the need to modify
ICU practices that put patients at risk of cognitive problems, and
to offer rehabilitation programs to restore concentration, thinking
and memory function after patients leave the hospital.
Intensive-care units traditionally keep patients heavily sedated,
immobilized and on mechanical ventilation to keep them free of
pain, anxiety and agitation as they heal or undergo invasive
procedures. But prolonged sedation can trigger or exacerbate
delirium, a temporary state of acute brain injury that can also be
caused by conditions such as septic shock, an infection that
spreads through the body and is a common reason for being admitted
to an ICU.
Delirium, long linked to higher rates of death, is also associated
with long-term mental impairment in ICU survivors, the study found.
E. Wesley Ely, senior author of the study and founder of
Vanderbilt's ICU Delirium and Cognitive Impairment Study Group,
said some ICU-related brain injury could be prevented if the
duration of delirium in the ICU is shortened. A new protocol
Vanderbilt and others are following includes weaning patients from
sedatives carefully, waking them regularly to see if they can
breathe on their own sooner, and getting them out of bed and moving
as soon as possible.
The study included 821 patients with respiratory failure or
septic shock who had a median ICU stay of 5 days. Their ages ranged
from 18 to 99. Only 6% had pre-existing cognitive impairment, and
75% developed delirium during their hospital stay. Assessed for
cognitive function at one year after discharge, 34% still had
scores similar to moderate traumatic brain injury, and 24% had
scores similar to patients with mild Alzheimer's disease. In total,
nearly 80% scored lower than predicted by age and education.
"Whether you are young or old and even if you are previously
healthy, if you go into an ICU with significant breathing problems,
are on a breathing machine or in shock, you may not be coming out
with an intact brain," said Dr. Ely. And after discharge, he adds,
"so many people are living in their own private hell of mental fog
and no one around them knows about it, tells them it is going to
happen, or tries to prevent or treat it."
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