October 28, 2010

Older sepsis survivors, cognitive issues linked

Older sepsis survivors, cognitive issues linked

Older adults who survive severe sepsis are at higher risk for long-term cognitive impairment and physical limitations than those hospitalized for other reasons, according to a study published in this week's Journal of the American Medical Association.

“There is an ongoing, rapid rise in the public health problem of cognitive impairment, or 'new dementia,'” said Wes Ely, M.D., professor of Medicine and the second author on the study.

Wes Ely, M.D.

Wes Ely, M.D.

“We spend tens to hundreds of thousands of dollars on patients to get them through the ICU experience, and they go home and have major trouble with thinking and memory.

“Most of them have problems with everyday things like finding their car in a parking lot, balancing their checkbook and going back to work,” Ely said.

This JAMA publication from an ongoing NIH study showed that 60 percent of hospitalizations for severe sepsis were associated with worsened cognitive and physical function among surviving older adults.

The investigation has primacy in revealing the odds of acquiring moderate to severe cognitive impairment were over three times higher following an episode of sepsis than for non-sepsis hospitalizations.

The authors prospectively evaluated 1,194 patients with 1,520 hospitalizations for severe sepsis enrolled into the Health and Retirement Study, a nationally representative cohort of U.S. residents. Survivors' mean age at hospitalization was 76.9 years. The investigation assessed cognitive function biannually through personal interviews.

Severe sepsis also was associated with greater risk for the development of new functional limitations following hospitalization, said lead author

Theodore (Jack) Iwashyna, M.D., Ph.D., assistant professor of Internal Medicine at the University of Michigan.

Sepsis is an overwhelming infection that can result in failure of multiple organ systems.

The initial infections are often common problems, such as pneumonia or a urinary tract infection. About 40 percent of those with severe sepsis die from the infection.

“Severe sepsis is one of the harshest illnesses the body can develop because in a matter of hours so many of your organs can shut down,” Ely said. “While many patients develop infections over days, this disease also can be sudden and furious.

“You're eating Cheerios in the morning and by the afternoon you're going to hell in a hand basket.”

To treat sepsis, physicians remove infectious sources, give antibiotics and resuscitative fluids, and often place patients on ventilators that beget heavy sedatives, which can cause delirium.

The Vanderbilt ICU Delirium and Cognitive Impairment Study Group recently published the first paper to document that delirium is an independent predictor of this long-term cognitive injury.

Tim Girard, M.D., MSCI, assistant professor of Medicine, and colleagues authored a paper in Critical Care Medicine that reported 71 percent of ICU survivors had cognitive impairment at one-year follow up, with delirium duration being the strongest predictor of subsequent brain damage.

“It is likely that the dose (duration) of delirium, especially in sepsis patients, essentially represents injury that is independently predictive of the problem of ongoing brain dysfunction in the ICU survivors. In all our cohorts to date, this relationship is most obvious in patients with severe sepsis,” Ely said.