General anesthesia may carry certain risks—postoperative hallucinations, delirium, and cognitive difficulties—for vulnerable populations. Protect yourself with these strategies.
For about a year, Phil Horton put off knee replacement surgery. "I kept thinking, 'Surely this will go away,'" says Horton, 76, who lives in Colorado Springs. "But it got more painful to walk. Finally, in January 2019, I had to have the surgery."
Illustration by Sam Island
Horton, who was diagnosed with Parkinson's disease in 2014, was more concerned than the average person about surgery because he knew about the effects of anesthesia on Parkinson's symptoms. He'd had general anesthesia during a previous operation, and for about a day and a half afterward he experienced hallucinations. "I'd see a creepy face out of the corner of my eye; when I looked over, it was gone," he says. "The hallucinations were mild, and I knew what they were, so they weren't as frightening as they might have been." He also noticed that his tremor worsened significantly for about three weeks following the operation. "For this [knee] surgery, I knew I had to talk to my neurologist, my surgeon, and my anesthesiologist about minimizing any problems that might be caused by the anesthesia," says Horton.
He was right to plan ahead. People with neurologic conditions such as Parkinson's and Alzheimer's disease can be particularly vulnerable to side effects and complications from general anesthesia, experts say. But by taking a team approach with their doctors, patients can minimize these risks and maximize their chances of the best recovery possible.
People with Parkinson's disease often have decreased respiratory function and a diminished cough reflex and swallowing ability, says Lauren Seeberger, MD, FAAN, associate professor and director of the Movement Disorders Center at the University of Colorado School of Medicine in Aurora. Because most of the anesthesia drugs used in surgery can slow respiratory function, Parkinson's patients are at higher risk for aspiration (when food or liquid gets into the lungs or airways, sometimes causing pneumonia) during surgery or recovery, she explains.
Dr. Seeberger notes that orthostatic hypotension—a failure of the nervous system to regulate blood pressure when a person changes body position, leading to dizziness and fainting—is more common in people with Parkinson's and can be worsened by anesthesia. And both general anesthesia and some pain medications can lead to hallucinations.
Anesthesia also poses risks for people with epilepsy, who may be more likely to experience seizures after surgery, says Frederick E. Sieber, MD, professor of anesthesiology and critical care medicine at the Johns Hopkins University School of Medicine in Baltimore.
In addition, medications for managing epilepsy and Parkinson's are often eliminated from the body relatively quickly and must be taken on a regular schedule to keep symptoms at bay. But taking an oral drug may not be possible when under anesthesia.
"These patients often have very specific times when they need to take their medications," says Dr. Seeberger. "If Parkinson's patients don't get their medication on time, for example, they may become more immobile or get significantly more tremor, and have less breath support, which can make it more difficult to recover from surgery."
For people with neuromuscular conditions, including muscular dystrophy, myasthenic syndrome, and motor neuron disease, certain types of anesthesia may come with risks, says Jeffrey A. Katz, MD, professor emeritus in the anesthesiology department at the University of California, San Francisco. In a 2017 review of the evidence published in Current Opinion in Anesthesiology, he and colleagues found that succinylcholine, a paralytic anesthesia, should be avoided in patients with muscular dystrophy, motor neuron disease, and intrinsic muscle disease. Potential complications include dangerously elevated potassium levels, malignant hyperthermia (a syndrome involving muscle rigidity, high fever, and a rapid heart rate), rhabdomyolysis (breakdown of muscle tissue that leads to the release of muscle fibers into the blood), and cardiac arrest.
How to Prepare
Most risks of anesthesia can be managed effectively with good communication, says Michael Avidan, MD, endowed professor of anesthesiology at Washington University in St. Louis. "You and your neurologist should talk to the surgical and anesthesiology team about your condition, your symptoms, and all your medications, and plan ahead for any potential problems."
For example, people with Parkinson's who require regular doses of oral medication and are undergoing a surgery that overlaps with the time they need to take a dose should ask their neurologist to confer with the anesthesiologist about options for administering the medication during surgery, and the risks of doing that versus delaying the dose.
Dr. Seeberger also encourages her patients to be in the best possible condition before receiving anesthesia to enhance recovery and lessen the likelihood of any complications. "A home course of swallowing and respiratory strengthening with a speech pathologist, for example, can help a person with Parkinson's avoid potential complications like aspiration pneumonia," she says.
Beyond disease-specific risks, the biggest concern about anesthesia for most people with neurologic conditions is cognitive dysfunction. It is true that postoperative cognitive dysfunction—a temporary decline in cognition, including memory or executive function—can occur after surgery and last a few days, a few weeks, or even months. It's particularly common in older individuals, says Dr. Avidan, adding that people with Parkinson's disease, epilepsy, Alzheimer's disease, a history of stroke, or certain heart or lung conditions may also be at risk.
"If you're over the age of 60, your chances of experiencing postoperative delirium are about one in four," he says. "It's a very distressing syndrome. You don't think clearly, you can have hallucinations and delusions, you're not able to pay attention, you can become paranoid and either agitated or lethargic. Most of the time, fortunately, it is reversible and temporary."
It had long been thought that the type or level of anesthesia contributed to postoperative delirium and that choosing lighter sedation could minimize the risk of the condition. But more recent research suggests this is not always the case. A 2019 study led by Dr. Avidan and published in the Journal of the American Medical Association (JAMA), which involved more than 1,200 older surgical patients, found that careful monitoring of brain activity and lower levels of anesthesia during surgery had no significant effect on delirium occurrence.
"My impression is that a much bigger contribution to postsurgical delirium is the actual trauma of surgery itself, rather than the anesthetic drugs," says Dr. Avidan. "While anesthesia may play a role, its contribution is likely to be much smaller than the big stress the body undergoes in response to this trauma. We know that older adults, particularly those with Parkinson's, Alzheimer's, or other conditions that contribute to cognitive impairment, are vulnerable to delirium after any insult to the body, and surgery is a big insult to the body." In fact, a June 2013 report in the British Medical Bulletin suggested that inflammation following surgery may be partially responsible for postoperative cognitive dysfunction.
While lighter sedation does not appear to reduce postoperative delirium overall, Dr. Sieber's research suggests that it may be beneficial in certain groups of patients. In a 2018 study published in JAMA Surgery, he found that for relatively healthy older patients, heavier anesthesia more than doubles the risk of delirium. "For these patients in particular, I would recommend a lighter dose of anesthesia," he says.
Precautions for Seniors
Elderly patients or those at risk for dementia should be assessed cognitively before surgery, says Angela Catic, MD, a geriatrician at Baylor College of Medicine and the Michael E. DeBakey VA Medical Center in Houston. "Patients should complete simple cognitive testing, including a three-word recall and a clock draw," she says. "Many times, people have underlying dementia, which is a risk factor for delirium, and an assessment can pick that up."
That baseline assessment can also help identify longer-lasting problems with learning and memory, which are distinct from delirium, she says.
Patients also should be asked if they have previously experienced postsurgery confusion, Dr. Catic says. "This significantly increases the risk of subsequent episodes of delirium."
The one thing that has been shown to be effective in preventing delirium and states of confusion after surgery is good, fundamental care of older patients, says Dr. Sieber. "And family members are very important to this," he notes. "Make sure patients stay hydrated. Assess their medications to avoid drugs that might cause confusion. Get them up and moving as quickly as possible, and make sure they have a bed near a window, so they can see when it's night and day. Make sure they have easy access to their glasses or hearing aids. All these things have been shown without a doubt to lower the risk of delirium and optimize cognitive outcomes after surgery."
Short-Term Effects
Dr. Avidan says most patients, including those with neurologic conditions, should expect a full neurocognitive recovery within the first few months after surgery. "Uncomplicated surgery alone, in most large studies, seems not to lead to long-term cognitive decline or dementia, and if there is an increased risk, that risk is likely to be very small," he says. "People planning elective surgery should generally be reassured that it is not unreasonably risky, if the surgery will enhance their quality of life and treat a condition that needs to be treated."
As for Phil Horton, after planning with his care team, he chose a spinal block instead of general anesthesia for his knee surgery. All went well, he says. His Parkinson's tremor was exacerbated, but it returned to normal sooner than with his earlier operation, and he had no hallucinations. He did experience orthostatic hypotension, which his doctors attributed to the opioids prescribed for postoperative pain, so they cut the dosage in half.
"I recommend that people with a neurologic condition do some research about their disease and reactions with anesthesia of any kind," Horton says. "Talk to your neurologist and be aware."
Surgery Checklist
Individuals especially vulnerable to anesthesia complications—including the elderly and those with a neurologic condition such as Parkinson's disease, Alzheimer's disease, or epilepsy—should consider these precautions.
- Disclose any health problems. "Always communicate any condition you have, especially if it relates to the heart or to breathing," says Frederick E. Sieber, MD, professor of anesthesiology and critical care medicine at the Johns Hopkins University School of Medicine in Baltimore. "The anesthesia team will determine how to adapt care accordingly."
- Consult a specialist. If you are elderly or a caregiver for a senior, try to include a geriatrician on the medical team, says Michael Avidan, MD, endowed professor of anesthesiology at Washington University in St. Louis. "Research [a 2012 study in Annals of Surgery] has shown that consulting with a geriatrician to develop a care plan before surgery reduces the likelihood of delirium."
- Review all medications. Tell your care team about all your medications—both prescription and over-the-counter—so they can make appropriate adjustments for ones that might be associated with cognitive problems.
- Get an assessment of your health. Everyone on your care team should know about any physical changes caused by your disorder and any neurologic changes that occur before surgery, says Dr. Sieber.
- Understand specific risks. If you have epilepsy, Parkinson's disease, Alzheimer's, or are in the advanced stages of multiple sclerosis, ask your neurologist about specific risks related to your condition.
- Manage postoperative pain. Talk to your surgeon or physician about a plan for dealing with postoperative pain, since "some drugs, such as narcotics, can provoke delirium," Dr. Sieber says.
- Ask about monitoring. Check with your care team about whether the amount of anesthesia you get needs specific monitoring based on your condition.
- Remember assistive aids. The American Geriatrics Society recently released a consensus statement on prevention of postoperative delirium, says Dr. Sieber. Patients should ask if certain proposed initiatives, such as ensuring access to eyeglasses or hearing aids, have been instituted in the hospital where they are having surgery. "If patients can hear and see adequately," he says, "it causes less confusion when interacting with the environment and other people."
Three Types of Anesthesia
Effective anesthesia induces temporary partial or total loss of memory, an inability to feel pain, relaxation of muscles, and loss of consciousness, all of which enable an operation or surgical procedure to go forward without patient discomfort.
Anesthetic agents work by targeting proteins in the membranes of nerve cells, blocking or inhibiting nerve transmission, says Michael Avidan, MD, endowed professor of anesthesiology at Washington University in St. Louis.
General anesthesia, administered as an inhaled gas or vapor, intravenously, or both, renders patients deeply unconscious and unable to move or feel pain.
Regional anesthesia is delivered by injection into a nerve cluster or group of nerves to numb the appropriate area. Because it blocks that region’s signals to the brain, this type of anesthesia is sometimes called a nerve block. Patients may remain awake or receive a sedative to relax them or make them unconscious, but they won’t feel pain in the region under anesthesia. (They will feel pain in regions that have not been anesthetized if, say, a surgical instrument falls there.) Epidural and spinal blocks are the most frequently used regional anesthetics. An epidural anesthetic is injected into the epidural space around the spinal cord, while spinal anesthesia is injected into the cerebrospinal fluid in the spinal cord.
A local anesthetic is injected directly into tissue such as the gums to numb a precise area where surgery will be performed.
https://www.brainandlife.org/articles/general-anesthesia-may-carry-certain-risks-postoperative-hallucinations-delirium-and/
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