Newswise — In a groundbreaking study to be highlighted at the 2008 Annual Meeting of the American Society of Anesthesiologists (ASA) Terri G. Monk, M.D., and colleagues from the Duke University School of Medicine explored the impact of multiple risk factors on the probability of postoperative delirium among older adults undergoing noncardiac surgery with general anesthesia.

By identifying a practical screening tool that can reliably identify risk factors known to increase the likelihood of postoperative delirium, medical teams will be better positioned to initiate proactive preoperative interventions to help minimize or prevent what has become an increasingly serious medical problem among older adults.

Delirium, which is sometimes accompanied by confused speech and hallucinations, is known to leave patients in an acute confused state where they experience a serious decline in cognition and attention.

It is believed that up to 50 percent of older adults experience delirium following general anesthesia. That -- combined with the current and looming increase in elderly patients " has significantly heightened interest among researchers in identifying risk factors that will help identify older patients best suited for preoperative intervention measures.

Aside from the detrimental impact patients personally experience with postoperative delirium, the economic repercussions resulting from longer hospital stays, elevated rates of admission to long-term care institutions, higher death rates and related healthcare costs are staggering. In 2004 alone, it was estimated that nearly $6.9 billion Medicare dollars were spent treating delirium.

For purposes of this study, the team from Duke submitted 100 patients 50 years or older undergoing noncardiac surgery to a screening for geriatric depression and a battery of five preoperative tests designed to measure their ability to process information, concentrate and self monitor. Postoperative delirium occurred in 16 percent of patients after surgery.

The results of the study indicated that the most reliable independent predictors of postoperative delirium were the geriatric depression score and the time required to complete the Trails B portion of what is known as the Trail Making Test " a cognitive flexibility task designed to measure perception, judgment, memory and so on in a shifting environment.

According to Dr. Monk, "This study demonstrates that a short preoperative cognitive test battery consisting of a depression and an executive function test requiring less than 10 minutes may help identify patients at greatest risk for postoperative delirium."

While these patients appeared to function normally prior to surgery, it is believed that they may have had some loss of critical brain mass that was not obvious without neurocognitive testing which may account for their predisposition for postoperative delirium.

Dr. Monk and her team view this study as an important first step in developing a practical and predictable screening tool that will help identify at risk patients for preoperative interventions and simultaneously reduce healthcare costs associated with the increased occurrences of delirium that might otherwise be expected with an aging population.

Anesthesiologists: Physicians providing the lifeline of modern medicine. Founded in 1905, the American Society of Anesthesiologists is an educational, research and scientific association with 43,000 members organized to raise and maintain the standards of the medical practice of anesthesiology and improve the care of the patient.

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American Society of Anesthesiologists 2008 Annual Meeting