April 6, 2001

Delirium, length of hospital stay related

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Katie Darnell was named an ambassador for Vanderbilt Children's Hospital at the Children's Miracle Network kickoff event on Monday. She sang her song "Rescue Me" at the White House on Wednesday. The group will also travel to Disney World for a weekend of fun with other CMN champions. (photo by Dana Johnson)

Delirium, length of hospital stay related

It’s extremely common for older patients to experience delirium while in the Intensive Care Unit (ICU) on ventilators. About 90 percent of elderly patients in the ICU suffer from some degree of delirium.

A study at Vanderbilt University Medical Center found that delirium resulting in the ICU is the no. 1 predictor of length of stay in the hospital – a finding that has caused one VUMC physician to design a series of investigations and protocols with cohorts at Vanderbilt and across the country to find out what can be done to reduce the incidence of delirium among elderly patients in the ICU.

Dr. E. Wesley Ely, assistant professor of Medicine, has been studying cognitive impairment in the ICU for the past two years. “We’ve been collaborating this series of investigations with people from all over the country,” he said. “It took a team of people with great expertise in a multitude of areas.”

At Vanderbilt the group includes: Drs. Robert S. Dittus, in general internal medicine; Gordon R. Bernard, in pulmonary and critical care medicine; Richard A. Margolin and Joseph Francis Jr., both experts in geriatric delirium; Alastair J.J. Wood in Pharmacology; Sharon Gordon, Ph.D., in Neuropsychology; Shiva Gautam, Ph.D. and Theodore Speroff, Ph.D., both biostatisticians; and Dr. Sharon K. Inouye, a geriatrician and delirium expert from Yale University.

The group has received a five-year National Institutes of Health grant to study delirium in older people as well as The Beeson Scholarship, a coveted three-year grant from the American Federation of Aging Research. Both grants begin July 2001. The American Geriatrics Society has selected the project from a list of 500 as one of the top 30 research projects and will highlight the project at the society’s annual meeting in Chicago in May.

“Deciding how to handle these patients is an emerging issue in critical care medicine,” Ely said. “We recognize that older people are going to the ICU and wondered if the older brain is more susceptible to deficits and the presence of delirium and if the complication, once developed, predisposes this group of patients to more long-term neuropsychological deficits.”

In the study, a group of patients in the adult medical ICU at VUMC was evaluated by geriatric psychiatrists and specially trained ICU nurses, Lisa May and Brenda Truman, for the development and persistence of delirium on a daily basis. The majority of patients (90 percent) developed delirium in the ICU. It was determined to be the strongest independent determinant of length of stay in the hospital, usually lasting from four to seven days, the study showed.

Ely said that delirium results from many causes. It is caused not only by the patients’ underlying illnesses, but also from factors such as the medications patients are given in the ICU, like sedatives or narcotics.

“There are numerous reasons patients become delirious,” Ely said. “These patients are also on the ventilator, have numerous metabolic disturbances, and often have to be restrained.”

Ely said that delirium should be studied as a target area for future intervention.

“While we have designed protocols for managing the ventilator, we should also devise protocols which might lessen or prevent delirium,” he said. “This might help elderly patients, who end up having to go to the ICU, to have better outcomes once they leave the ICU. They will know who they are, why they were there, and they will be able to go home, balance the checkbook, go back to work and enjoy their lives.”

It is not easy to measure delirium because patients in the ICU are often intubated and unable to talk, Ely said. So intubated patients were excluded from previous studies. But Ely said these patients should not be excluded since they’re at the highest risk to develop delirium.

So he and his group devised a tool called the Confusion Assessment Method for the ICU (CAM-ICU). It’s a two-minute nursing bedside assessment that the group compares to delirium assessments of geriatric psychiatrists.

“We found that the reliability of the bedside nursing assessment is between 92 and 98 percent, with a sensitivity and specificity of 85 to 95 percent,” he said.

Ely said the group is excited about the NIH and Beeson grants.

“This is an exciting project and one of the major strengths of Vanderbilt has been demonstrated in our story – that under one roof one can create such an incredible team of health care professionals to study the major problems identified in a patient’s care. And these people, truly renowned in their fields, are here under the envelope of Vanderbilt. That is why the NIH and AFAR are embracing our institution, allowing us to do this research.”

Ely said future plans are for the group to look at the relative impact of the risk factors for delirium – which are modifiable and how they can be reduced. They also plan to study whether or not specific pharmacological agents can reduce delirium.

Ely’s previous research has included published studies about mechanical ventilation in the ICU, including work published in the New England Journal of Medicine and The Annals of Internal Medicine.