For some people who’ve had general anesthesia, shaking it off can be a bit of a process. While advances in surgical and anesthesia techniques, along with improved preoperative care, have made surgeries safer than in the past, much less is known about how surgery and anesthesia affect the brain. For older adults, the risk of cognitive impairment following surgery isn’t one that’s often discussed.
State of confusion
Doctors use medications inhaled through a breathing mask or tube, drugs administered intravenously, or a combination of both to induce unconsciousness and prevent patients from feeling pain, typically just before surgery begins. After surgery, as the anesthesia wears off, 20 to 45 percent of older patients may become disoriented or confused for a few minutes. Some patients, however, may be confused and have memory problems for up to a week after surgery, a condition called postoperative delirium. This type of delirium is often associated with major surgical procedures or a complicated recovery.
Some patients experience symptoms of cognitive problems such as memory loss, difficulty concentrating, lack of coordination, and the inability to make decisions and solve problems. This temporary state of cognitive dysfunction is sometimes referred to as delayed neurocognitive recovery or perioperative neurocognitive disorder. Unlike delirium, which occurs immediately after surgery, delayed neurocognitive recovery can appear at any time within 30 days of surgery—and can last just as long. For a small percentage of patients, it can take as much as a year to recover. A small number of people who experience delayed neurocognitive recovery have an increased susceptibility to long-term or permanent cognitive dysfunction.
No agreement on cause
The cause of delayed neurocognitive recovery is an issue of debate. While some researchers point to the general anesthesia used during surgery, others believe the inflammatory response caused by the surgery itself may lead to delayed neurocognitive recovery. Research has shown no difference in the incidence of delayed neurocognitive recovery in those undergoing one type of anesthesia over another. Nor is there any difference between general and regional anesthesia, which produces variable degrees of sedation and blocks pain in a large region of the body.
Because it’s difficult for researchers to study anesthesia and surgery independently, they are limited in their ability to pinpoint the exact cause. Despite this, they have identified consistent risk factors for delayed neurocognitive recovery, including advanced age, preexisting cognitive impairment, and a lower education level, which indicates lower cognitive reserve. (Cognitive reserve is attained by routinely challenging the brain by learning and experiencing new things.) Parkinson’s disease, lung disease, and heart disease (especially heart failure) are also risk factors for delayed neurocognitive recovery.
If you’re preparing for surgery, you and your doctor can take steps to help lower your risk of postoperative delirium anddelayed neurocognitive recovery:
- Ask for an anesthesiologist who specializes in geriatric anesthesiology. He or she can help reduce your risk of developing any age-related problems from anesthesia. Before surgery, your anesthesiologist will ask you questions about your medical history, medications, and lifestyle habits. This information helps the doctor understand how you might react to anesthesia and take steps to lower the risk of side effects. Be sure to describe any issues you’ve experienced with anesthesia in the past, including any memory or thinking problems.
- Talk with your doctor about a presurgery cognitive test. The results from an assessment of your mental function can be used as a baseline for comparison following your procedure to identify any issues as quickly as possible.
- Have a friend, family member, or caregiver stay with you in the recovery room. Someone who knows you well can recognize any troubling signs of cognitive dysfunction and inform your doctor or other hospital staff.
- Orient yourself after surgery. While it might seem prudent to leave hearing aids or glasses at home so they don’t get lost, not having access to them as you recover can increase the likelihood of delirium following surgery. Request a room with a window, if possible, so you can tell what time of day it is. If you’ll be staying overnight, pack a photo of loved ones, a clock, a calendar, and other familiar items, which can help you readjust.
- Drink water and move around after surgery if possible. Staying hydrated and increasing mobility have been associated with a decreased risk of delirium and cognitive impairment after surgery. Follow your care team’s guidance for walking, eating, and drinking.
- Check with your doctor before resuming medications. If you take any medications that can affect your nervous system, such as those for anxiety, seizures, muscle spasms, or insomnia, talk with your doctor before taking them again.
If you’re concerned about your cognitive function in general, ask your doctor what you can do to stay sharp and improve your brain health.
This article first appeared in the April 2020 issue of UC Berkeley Health After 50.
Also see Statins: Not Bad for the Brain.