April 10, 2009

New tool helps gauge delirium in children

Featured Image

Heidi Smith, M.D., center, and Jenny Boyd, M.D., work with patient Cyan Scarpati in the Pediatric Critical Care Unit. (photo by Joe Howell)

New tool helps gauge delirium in children

When Wesley Ely, M.D., and his colleagues completed groundbreaking research on delirium in the adult intensive care unit (ICU) in 2004, they found an alarming increase — threefold to sixfold — in the risk for death if delirium had been diagnosed. There was also a significantly higher risk for long-term cognitive impairment.

Now Ely's work is being applied to Vanderbilt's youngest patients. His work has inspired a four-person team at the Monroe Carell Jr. Children's Hospital at Vanderbilt to tackle the difficult task of developing a bedside nursing tool to assess for delirium in children in the ICU.

Heidi Smith, M.D., assistant professor of Pediatric Critical Care, and principal investigator of the study, says delirium is relatively uncharted territory in pediatric critical care. She and her colleagues believe the risks Ely found for adults may be the same for children.

“Children hospitalized in Pediatric Critical Care Units (PCCUs) are currently not monitored for delirium. Even when this common type of brain dysfunction is diagnosed, the medical community uses different terms, like ICU psychosis, encephalopathy,” Smith said. “When you see these terms in the literature, it's not clear we're even talking about the same condition.”

Delirium is a syndrome of brain dysfunction which can be caused by brain injury or disease, or by complications associated with critical illness or its treatment.

“Hyperactive delirium is easier to diagnose than hypoactive delirium because children pull out their lines and become difficult to work with. But hypoactive delirium is much more subtle and therefore more difficult to diagnose,” said Catherine Fuchs, M.D., chief of the Division of Child and Adolescent Psychiatry and co-principal investigator of a study to validate the new tool.

Smith, along with Pediatric Critical Care fellow Jenny Boyd, M.D., Fuchs, and Child Psychiatry fellow Kelly Melvin, M.D., began by taking Ely's Confusion Assessment Method for the ICU (CAM-ICU), which has been validated for use in adults, and adapting it. The goal was to make it developmentally appropriate for the age range of 5 to 18 years.

“Pictures used for assessing memory and inattention were black and white for adults, so we replaced than with boldly colored images children could easily recognize,” Boyd said.

“Also, questions used to assess disorganized thinking were substituted with age-appropriate content. An adult might be asked 'Can you lift a 1,000-pound car?' For a child who might not grasp the concept of pounds we might ask 'Do rabbits fly?' Or 'Is a giraffe smaller than a mouse?'” Boyd explained.

The changes may seem small and cosmetic, but precision is critical for a bedside nursing tool when assessments must be short, clear and not taxing to the patient.

The overhauled tool has been dubbed the pCAM-ICU, for Pediatric Confusion Assessment Method for the ICU. Testing the tool began last year in the PCCU. They continue to enroll patients age 5 to 18 who are ventilator dependant.

The tool is designed to be used by nurses once a day. It takes about 90 seconds to assign a score to four features of mental function. If a child receives a particular combination of scores, they are considered positive for delirium. Within three hours, a psychiatric team comes to perform the current evaluation for delirium for comparison.

So far the pCAM-ICU tool has a better than 90 percent accuracy rate. Smith says it will be instituted as usual care in the PCCU here at Vanderbilt. Testing on mechanically ventilated children continues and has been expanded now to include patients at Cornell University. Results will be published this year.

“The primary treatment for delirium is to treat the cause, but first you need to know it's there,” Melvin said. “There are a number of known causes of delirium: hypoxia (low oxygen), infection, metabolic changes to name a few. But more needs to be known about how often it occurs, what is the impact. We need to be able to better balance positive effects of sedation and pain relief with side effects like delirium,” Melvin said.

“An assessment tool will allow for research in all these areas.”