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Imagine entering the intensive care unit with one illness like pneumonia – and then leaving with an entirely different debilitating health condition affecting your memory, organizational skills and overall quality of life

It turns out that long-term brain dysfunction is a reality that many patients must face after a stay in the intensive care unit (ICU), according to a new study  from Vanderbilt University Medical Center published in the New England Journal of Medicine.

“As survival has increased from critical illness based on modern medical therapies, we see a lot of patients coming back with memory problems, problems doing day-to-day activities,” study author Dr. Pratik Pandharipande, a professor of anesthesiology and critical care at Vanderbilt University Medical Center, told FoxNews.com. “Patients are telling us just getting us thorough the ICU and being a survivor is not good enough. They say, ‘We want to be back to where we were before we were in the ICU.’”

In an effort to improve quality of life for ICU patients post-treatment, Pandharipande and his team set out to discover what was happening in the ICU that was causing patients to experience such high rates of debilitating cognitive impairment.

Researchers analyzed 821 patients who had been admitted to the ICU with respiratory failure, cardiogenic shock or sepsis. Overall, they discovered that three months after leaving the ICU, 26 percent of patients had cognitive impairment symptoms similar to those seen in early Alzheimer’s disease, and 40 percent of patients had levels of cognitive impairment comparable to those seen in concussion victims.

Additionally, these effects were still visible months later. A year after their initial hospital stay, 24 percent of the patients still demonstrated levels of cognitive impairment similar to Alzheimer’s disease and 34 percent were still experiencing concussion-like levels of impairment.

“Even patients below 50 years of age had significant cognitive impairment,” Pandharipande said. “Another significant finding was whether you had prior disease or not, you still had this risk.”

In seeking an explanation, Pandharipande and his colleagues focused on delirium – a condition commonly seen in the ICU and characterized by brain dysfunction leading to confusion, fluctuating mental status or decreased levels of consciousness.

“There are early studies looking at what delirium does to the brain, and what people have found is that patients who have longer durations of delirium have more brain atrophy, more inflammation…and this could potentially be the connection between delirium and long term cognitive impairment,” Pandharipande said.

The researcher’s suspicions proved correct. They ultimately discovered that the longer patients experienced symptoms of delirium in the ICU, the worse their cognitive impairment after their stay.

“A number of studies have shown in recent years that delirium is not an innocent bystander of ICU care but is a real issue associated with worse outcomes, longer time in the ICU, on ventilation, even a predictor of mortality,” Pandharipande  said. “And now, if you survive, it’s a predictor of cognitive impairment.”

Pandharipande and his colleagues are now exploring methods to reduce the duration of delirium in ICU patients.

“A couple of things that have already been studied and have an impact are reducing sedative exposure…and having patients alert and getting them mobilized faster out of ICU beds,” Pandharipande said. “Sitting, walking – all have been shown to reduce duration of delirium.”

The team hopes their research will also encourage physicians to offer patients cognitive rehabilitation in addition to the physical rehabilitation that is typically prescribed after a serious illness.

“We hope to bring awareness to this problem so...when patients start complaining early in recovery period, it’s not blown off, but people actually try to get them involved in therapy programs,” Pandharipande said.