It’s not clear exactly what causes delirium—and it is difficult to untangle cause and effect because people who are older and already have some cognitive impairment are at greatest risk of experiencing delirium. Some researchers believe anesthesia during surgery may play a role. Others suspect ventilators may be associated with the condition in patients who haven’t had surgery.
Either way, doctors say people can take steps to minimize their chances of experiencing delirium and lessen its potential damage. Patients with existing cognitive problems should assess whether they truly need elective surgeries. And people who must have surgery should maintain a healthy diet and exercise level beforehand, and talk with their doctor about the use of anesthesia.
“It’s been shocking to me not only how common this is but that health care providers often don’t know how to deal with it appropriately,” says Sarah Lock, AARP’s senior vice president of policy and brain health. The group is working on a report on delirium, expected to be released in March.
The advocacy group for people 50 and over held a roundtable on the issue last year. Ms. Lock said it became clear that many doctors saw delirium as a normal but temporary state that didn’t have a long-term impact. “We now know that it is often preventable and that people who are already experiencing cognitive decline when they go into the surgery get worse and have worse outcomes,” she says. “So it’s not a normal side effect that just goes away.”
Among the expected recommendations is preparing for surgery with “prehab.” This includes exercising, eating a healthy diet, staying hydrated and evaluating the medications and supplements you’re currently taking. Ms. Lock also recommends preparing caregivers to provide assistance before, during and after the surgery.
Sharon Inouye is a geriatrician at Hebrew SeniorLife and professor at Harvard Medical School who studies delirium patients. Her research shows that 20% to 30% of patients over the age of 70 who have a major surgery will experience delirium that is associated with subsequent long-term cognitive decline and increased risk for developing Alzheimer’s disease or a related dementia later.
Her research involves 560 patients who had no signs of Alzheimer’s before surgery and following them for up to eight years. Among the findings is that patients who had the very earliest signs of memory loss beforehand had more rapid cognitive declines following delirium.
Patients with postoperative delirium usually experience their most intense symptoms two days after a procedure, says Dr. Inouye, and symptoms resolve a few days later. But for some patients, delirium can last for weeks or even months.
She believes delirium is likely caused by a combination of factors, including undergoing a major surgery, taking anesthesia and postsurgical medications, and other stressors in the hospital, she says. “It’s related to a lot of really stressful things that occur during hospitalization,” says Dr. Inouye.
More than 200 hospitals have instituted a program started by Dr. Inouye that is aimed at preventing delirium. Called Hospital Elder Life Program, it includes steps like getting patients moving as soon as possible, giving them their glasses and hearing aids, and making sure they get proper sleep without the use of sleep medications.
Experts don’t know whether some types of anesthesia are riskier than others—it’s not clear whether general or regional anesthesia is riskier, for instance. Dr. Inouye says keeping the exposure to anesthesia as short as possible and cutting down on the number of psychoactive drugs used can help.
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Some laboratory studies have found that when human neuronal cells are exposed to certain inhaled anesthetic agents, the cells can start to generate the precursors of amyloid proteins, which are associated with Alzheimer’s disease. “So it does appear that in some cases the anesthetic itself can trigger a phenomenon that you can see before Alzheimer’s disease,” says Dr. Inouye.
The amount of anesthesia may play a role for some patients, says Lee Fleisher, professor and chair of anesthesiology at the University of Pennsylvania and chair of the American Society of Anesthesiologists Brain Health Initiative. He has a grant to conduct research looking at whether general anesthesia used for surgery is associated with an increased risk of developing dementia.
“We suspect that if you’re incredibly sensitive to anesthesia, that may predict the group that goes into delirium,” says Dr. Fleisher. “It may not be giving too much but more about high sensitivity.”
He recommends avoiding medications like Benadryl and Valium after surgery. The trick, he says, is being able to manage pain with the smallest possible amount of narcotics. Using regional anesthetics called nerve blocks that numb just one area after surgery is ideal, he says.
He says older patients considering an elective surgery should have a geriatrician give them a cognitive screening. If the results show cognitive impairment, patients should weigh the risks and benefits of the surgery.
Malaz Boustani, a professor of aging research and director of the Center for Health Innovation and Implementation Science at Indiana University School of Medicine, is working with colleagues to develop a trial testing whether noise reduction, avoidance of inappropriate medications, cognitive stimulation, and early mobility can reduce the chances of postoperative delirium. “We’re working on delirium prevention as a way to prevent Alzheimer’s disease,” says Dr. Boustani.
Dr. Boustani has family links to the condition. His father-in-law developed postoperative delirium after a carotid artery surgery. Two years later he was diagnosed with dementia. He died in 2016 from complications related to dementia.
“I promised my family members that I would recruit the right scientists and work to reduce delirium and thus prevent dementia,” says Dr. Boustani. “This is personal for my family and I.”
Seeking Support
At Vanderbilt University School of Medicine in Nashville, Tenn., a weekly support group of former intensive care unit patients who are suffering from cognitive difficulties convenes every Tuesday. Most don’t have full-blown dementia, but mild to moderate cognitive problems after a bout of delirium.
Wes Ely, a professor of medicine at Vanderbilt, focuses on ventilators as a potential risk factor for developing delirium. More than half of patients who leave an ICU who were on a ventilator or medications to stabilize their blood pressure have some element of cognitive impairment. About a third of such ICU patients will develop at least mild to moderate dementia.
One outstanding question, says Dr. Ely, is what kind of dementia these patients develop. Many of their symptoms present differently than typical dementia or Alzheimer’s disease. He recently started a study looking at the brains of about 500 deceased ICU patients.
Glynda McAlister, a 63-year-old from Clarksville, Tenn., started attending the Vanderbilt support group in May after an ICU stay from an infection that became septic left her delirious for a few days.
She says she’s never been the same, though a neurologist said she doesn’t have mild cognitive impairment or dementia. She had to give up her job as a trainer for a call center, as she can’t use a computer. She doesn’t remember how to play the piano. She can’t drive and she no longer cooks. “Everything takes me a lot longer than it did before,” says Ms. McAlister. “If I’m out of my routine, I can’t do every day simple things.”
She gets by with the help of her grown-up children and the support group, she says. She makes lists. She uses Alexa to help remember things. And she’s starting to dabble in new things, like crafting, and getting to know her new self. “This is the new normal for me,” she says.