Many older adults who have major surgery experience postoperative delirium in the days after their operations. Previous research has suggested that closely monitoring the brain during surgery and making adjustments to protect the brain from too much anesthesia could reduce risk of postoperative delirium.
But in a new study of more than 1,200 older surgical patients at Barnes-Jewish Hospital in St. Louis, researchers at Washington University School of Medicine found that meticulously monitoring brain activity and then taking care to minimize levels of anesthesia during surgery had no significant effect on the occurrence of delirium. However, in the group that had close brain monitoring, there were fewer deaths in the first 30 days after surgery. That was an unexpected finding, and the researchers believe it points to potential benefits linked to close brain monitoring and should be examined in future studies.
The findings are published Feb. 5 in the Journal of the American Medical Association (JAMA).
Delirium, described as a state of confusion or agitation, is common after surgery. It is unpleasant but almost always temporary. However, it has been linked to longer stays in intensive care units, more total days in the hospital and even a higher risk of death. About 25 percent of older surgery patients experience postoperative delirium, so finding ways to prevent delirium has been identified as a public health priority by several groups, including the American Geriatric Society, the American Society of Anesthesiologists and the National Institute on Aging at the National Institutes of Health (NIH).
“When older adults have major surgery, one in four of them experiences delirium. That’s a large number,” said principal investigator Michael S. Avidan, MBBCh, the Dr. Seymour and Rose T. Brown Professor of Anesthesiology. “If there is a way to change that, it would have a major impact on public health.”
There were 1,232 patients in the study. Half were randomly assigned to very close monitoring of the brain’s electrical activity, as measured by electroencephalogram (EEG) during surgery, and the rest were given usual care during their operations. The researchers found that 26 percent of the closely monitored group still experienced delirium in the first five days after surgery. By comparison, 23 percent of those in the group that did not receive such close monitoring of brain activity developed delirium during the same time period. That difference was not statistically significant.