Nearly 80% of patients who stay in the ICU for a prolonged period—often heavily sedated and ventilated—experience cognitive problems a year or more later, according to a new study in NEJM.

For the study, Vanderbilt University researchers studied 821 patients with respiratory failure or septic shock who stayed in an ICU for a median of five days. Researchers tested the patients' cognitive skills during their hospital stay and one year after they were discharged. 

They found that during the patient's hospital stay:

• 75% of the patients developed delirium; and
• 50% exhibited problems similar to those with Alzheimer's disease.

A year after discharge, researchers found that:

• 34% of the patients exhibited signs of a moderate traumatic brain injury; and
• 24% exhibited signs of with mild Alzheimer's disease.

"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," lead author Wesley Ely told the Wall Street Journal. He added that following discharge, "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."

Keeping patients heavily sedated or on mechanical ventilation to keep them free of pain is common in ICUs, but prolonged sedation can trigger or exacerbate delirium. Some patients, who come to the ICU as a result of septic shock from an infection, are already experiencing some delirium as a result.

Making changes to ICU practices

When patients are critically ill, hospital teams often say, "'let's keep them sedated and not wake them up and interact with them, or let them interact with the environment,'" according to co-author Pratik Pandharipande. "After an illness, the lung, heart and kidneys tend to recover, but the brain probably has the least reserve, and illness may have longer lasting implications," he added.

Pandharipande says that hospitals should consider using light sedatives and when patients need to sleep, not be bothered by tests.

As a result of the study, Vanderbilt implemented a system to wean ICU patients off 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 researchers say they hope that other hospitals will follow their lead and employ rehabilitation programs to restore cognitive and memory functions after discharge (Ely et al., NEJM, 10/3; Clark, Health Leaders Media, 10/2; Landro, Wall Street Journal, 10/2).