How General Anesthesia Can Affect a Senior’s Cognitive Function

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As a person ages, the chance that they will need to undergo surgery requiring the use of general anesthesia increases. General anesthesia describes the combination of intravenous and inhaled drugs used to render an individual unconscious and unable to feel pain during an operation. This type of intervention is typically used for surgeries that will take a long time to complete, cause a great deal of physical and mental discomfort, or possibly interfere with a person’s ability to breathe.

The process of “going under” usually doesn’t present a problem for younger, healthier individuals. After a few days, any residual feelings of grogginess or confusion typically wear off. However, older individuals process these drugs differently and can experience more severe side effects.

How General Anesthesia Affects Seniors

“General anesthesia does carry a higher risk for the elderly population,” says Damon Raskin, MD, a board-certified internist and medical director for two skilled nursing facilities. According to Dr. Raskin, it takes longer for an older person’s body to rid itself of the chemicals involved in anesthesia, which can prolong the negative effects of the drugs. Because of this, many seniors report feeling foggy, slow or downright confused for days, weeks or even months after a surgical procedure.

The situation becomes increasingly complex if a patient also suffers from other health conditions, such as diabetes, heart disease, cancer, etc. For example, people with Parkinson’s disease are more prone to experiencing bouts of confusion and hallucinations that may not appear until days after a surgery was performed. Not only is this distressing for patients and their families, but this can also have a negative effect on the type of post-operative care these individuals receive, caution experts from the Parkinson’s Foundation.

The Connection Between Anesthesia, Delirium and Dementia

When examining the potential cognitive effects of general anesthesia, it’s important to first make the distinction between two commonly confused conditions: delirium and dementia.

While these ailments share similar symptoms, such as confusion, problems with perception, mood swings and decreased cognition, there is one crucial difference that separates them. Delirium refers to abrupt, temporary changes in a person’s mental functioning, whereas dementia describes a more gradual, permanent decline in cognitive abilities. People with dementia can exhibit signs of delirium, but the two terms are not interchangeable.

Hospital-induced delirium is a common cognitive after-effect of hospitalization and general anesthesia, particularly for the elderly. This has led to a flurry of research studies aimed at determining whether being “put under” can cause permanent brain changes or even dementia. However, results of these investigations have been mixed. Furthermore, because studies on this topic have been inconclusive, there is little agreement on the terminology used to describe the confusion older patients experience following surgery. Post-operative cognitive dysfunction (POCD) is yet another term that specifically refers to a decrease in cognitive ability that can occur for weeks or months after a significant surgery.

Deciding Whether a Senior Should Undergo Surgery

As a caregiver, it can be hard to know what to do when a doctor says your loved one needs surgery. The link between dementia and general anesthesia remains fuzzy, but there’s no doubt that going under can cause lingering physical and cognitive issues for older adults. Many seniors bounce back after procedures like hip replacements and hernia operations, but some never return to their pre-operative cognitive baseline.

It’s crucial to communicate with all members of a patient’s health care team to determine the risks and benefits of a proposed procedure. When making this decision, consider the patient’s age, physical and mental health status, and the anticipated effects on their quality of life. For example, if a senior is still very active and in decent shape, but suffers from excruciating arthritis, joint replacement could significantly enhance their quality of life, mobility and functional ability. A senior’s ability to participate in post-op rehabilitation is also an important factor in this decision.

Another important consideration is whether less intense sedation could be used during the procedure. Regional anesthesia used in conjunction with a sedative can be a safe and effective alternative to general anesthesia for many surgeries. The recovery time, pain, side effects and cost are often less with regional types of anesthesia, such as epidurals, nerve blocks and spinal anesthesia. However, these approaches aren’t used in most open-heart, abdominal and brain surgeries.

A Pre-Op Evaluation Is Crucial

Scientists are still investigating possible causes and risks for POCD, but one key to preventing unnecessary complications from surgery is to undergo a thorough pre-operative evaluation with a primary care physician. The surgeons and anesthesiologists who will be involved in the procedure need to be made aware of a patient’s important health information, including:

  • Their medication regimen.
    The drugs used in general anesthesia can negatively interact with some prescription medications, including beta-blockers (e.g. Tenormin, Corgard, Sectral), oral hypoglycemics (e.g. metformin) and monoamine oxidase inhibitors (e.g. Parnate, Emsam, Marplan, Nardil). Blood thinners, another common class of medication taken by the elderly, can also cause problems with bleeding during invasive procedures. All doctors involved should know about all prescription and over-the-counter drugs as well as dietary and herbal supplements a patient takes so that they can provide specific instructions for continuing, tapering off or stopping certain medications before a surgical procedure.
  • Their pre-existing conditions.
    Every medical issue, no matter how seemingly small, can potentially impact a patient’s experience both during and after a surgical procedure. Dr. Raskin cautions that urinary tract infections (UTIs) and other infections can cause huge problems during surgery and should always be disclosed in advance. For those with lung and/or heart conditions, more specialized tests and examinations may be necessary.

The doctor in charge of coordinating the procedure should make sure this and any other relevant information is communicated to the surgical team. Meeting with the anesthesiologist in person to go over important medical concerns is also an option to consider. Undergoing general anesthesia carries risks for people of every age but making sure the surgical team is up-to-date on an elderly patient’s health status will reduce the risk of adverse mental (and physicial) side effects.

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13 Comments

Oh, how I can attest to the truth in this article! It is not surprising to see that two studies on this came with different conclusions: although clinical studies are based on only that which can be concisely, accurately documented, there are so many variations inherent in every person, and their reactions to drugs, that it's difficult to come to any final conclusions....there will hopefully be more studies in this! It is desperately needed!

As for my scenario, mom absolutely had to have a 2nd major operation (hip replacement): the first hip replacement had been done with an implanted device that was recalled by the mfr.; this we discovered after mom had suffered 3 hip displacements. We knew she would most likely be worse off mentally afterward and we were correct. Her dementia is profound, she is completely wheelchair-bound, will not even attempt to walk (refused PT almost immediately after the 2nd surgery, got so combative that it was pointless to continue), is completely incontinent and will spend the rest of her life in a nursing home. It is incredibly tragic and sad; difficult to deal with and has radically changed everyone's life in our family.

I applaud every bit of information that this site makes available to caregivers. Knowledge is power!
I was never aware anesthetic could affect the brain this way.This answers a lot of questions of why a 61 year old became lethargic,said she couldn't think or operate her power chair properly since a shoulder replacement and trauma surgery on her leg. More should be done to monitor brain activity during surgery. I read an article how there is a higher risk to children for permanent neurodevelopmental like language comprehension and a lower IQ.
Maybe it is too obvious (or too risky for Big Pharma profits), but too much anesthetic, like too much alcohol, is clearly not good for the brain, especially in those over 50.

The goal of my non-profit Goldilocks Anesthesia Foundation is to make brain monitoring a standard of care.

Vital signs, like heart rate and blood pressure, only reflect brain stem activity. However, the target of anesthetics is the cortex, the top part of the brain.

Since 1996, we have the ability to directly measure brain response to anesthetics. The BIS may not be perfect but it is the best available technology to avoid routine over medication, the standard practice without this critical information.

To properly inform prospective surgery patients, read 'Getting Over Going Under, 5 things you MUST know before anesthesia.'