Underlying depression and less cognitive flexibility could be warning signs

A recent study showed that health-care costs go up another $2,500 for each patient with delirium following surgery, because of longer hospital stays, higher death rates and the need sometimes to admit patients to long-term care. The annual national cost may reach as high as $152 billion a year, Monk said.
"When you look at the increase in the aging population, this is going to be more of a problem," she added.
Dr. Arnold Berry, a professor of anesthesiology at Emory University School of Medicine, Atlanta, said the impact of the problem is already clear, considering that about 12 percent of the U.S. population is 65 or older and this group accounts for one-third of expenditures on surgery.
The Duke study of 100 patients, averaging 65 years of age, found that 16 percent experienced post-operative delirium after they'd received general anesthesia for non-cardiac surgery. Specific percentages can be as high as 50 percent or more for patients having surgery following a hip fracture, Monk noted.
The two pre-surgery tests -- the Geriatric Depression Scale-Short Form and the Trail Making Test -- can be administered by nurses and other health-care personnel in as little as 15 minutes, Monk said. The finding that these tests are effective screening tools could lead to further research to identify measures to prevent or reduce post-operative delirium, she said, adding that current interventions are limited.
For example, further research might show that treating depression in older patients prior to elective surgery reduces their likelihood of post-operative delirium, she said.
Monk is scheduled to present the study's findings Oct. 20 at the American Society of Anesthesiologists' annual meeting, in Orlando, Fla.
Emory's Berry, who leads a group of anesthesiologists interested in geriatric issues, said Monk's findings are "one piece to a big puzzle." Because of changes in the aging brain, it's difficult to determine how much the stress of surgery and how much anesthesia add to the risk of post-operative delirium, he said.
The Duke study identifies screening tools that could spur more research into ways of dealing with both factors as they relate to post-op delirium, Berry explained. He said he doesn't plan to add the screening tools used in the Duke study to his pre-operative work-ups -- at least not yet.
"They are something that's promising, but I think most people would wait until it has undergone peer review and has been published," he said.
Monk said the study has been submitted for publication.
In a related study, Canadian researchers reported last month that people who take cholesterol-lowering statin drugs -- such as Crestor, Lipitor, Pravachol and Zocor -- are more likely to suffer delirium after surgery. That finding was published in the Canadian Medical Association Journal.