Cognitive Effects of Anesthesia on the Elderly


As a person ages, the chance that they will need to undergo surgery requiring the use of general anesthesia increases. In fact, studies have estimated that 53 percent of all surgical procedures are performed on patients over the age of 65.

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/or mental discomfort, or possibly interfere with a person’s ability to breathe.

The process of “going under” usually does not 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 that may outweigh the benefits of certain surgical procedures.

Effects of Anesthesia on Elderly Patients

“General anesthesia does carry a higher risk for the elderly population,” admits Damon Raskin, MD, a board-certified internist and medical director for a hospice provider and two nursing homes in the Santa Monica, CA, area. 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 these 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 or heart disease. For example, people with Parkinson’s disease are more prone to experiencing bouts of confusion and hallucinations that may not present until days after having surgery. Not only is this distressing for patients (and their families), but experts from the Parkinson’s Foundation caution that this can also have a negative effect on the type and quality of post-operative care they receive.

When it comes to seniors with cognitive conditions like Alzheimer’s disease and other types of dementia, it can be difficult for doctors and family caregivers to weigh the benefits and potential drawbacks of surgery. Anecdotes often point to a direct connection between anesthesia and dementia, but this cause-and-effect relationship is far more complex than it seems.

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The Connection Between Anesthesia, Delirium and Dementia

When examining the potential cognitive effects of general anesthesia on older adults, it is 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 are crucial differences between them. Delirium refers to abrupt, temporary changes in a person’s mental functioning, whereas dementia describes a more gradual, permanent decline in cognitive abilities caused by chemical and/or anatomical changes in the brain. People with dementia can exhibit signs of delirium, but the two terms are not interchangeable.

Postoperative delirium (a contributor to hospital-induced delirium) is a common cognitive after-effect of general anesthesia, particularly for the elderly. The American Society of Anesthesiologists (ASA) explains that confusion, difficulty focusing and memory issues associated with postoperative delirium “can come and go and usually disappear after about a week.”

Postoperative cognitive dysfunction (POCD) is a more severe condition that may affect seniors who have received monitored sedation or general anesthesia. POCD is characterized by marked changes in cognition and both short- and long-term memory that can persist for weeks or months after a significant surgery. According to the ASA, the following chronic conditions can increase a senior’s risk for POCD:

  • Heart disease (especially congestive heart failure)
  • Lung disease
  • Alzheimer’s disease
  • Parkinson’s disease
  • Stroke

Increased awareness of postoperative delirium and postoperative cognitive dysfunction have led to a flurry of research aimed at answering one important question: can anesthesia cause dementia? Unfortunately, the results of these investigations have been mixed. Even without factoring in the effects of anesthesia, it is important to understand that surgery is traumatic to the body and mind. The entire process from pre-op evaluation through post-op care involves a great deal of physical and mental stress, which can be very hard on frail older adults. These and many other factors likely influence changes in memory and cognition following operations.

Should General Anesthesia Be Avoided in the Elderly?

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 anesthesia remains fuzzy, but there is no doubt that going under can cause lingering physical and cognitive issues for some older adults. Many seniors bounce back after procedures like hip replacements and open heart surgery, but some never return to their preoperative cognitive baseline.

It is crucial to communicate with all members of a senior’s health care team to weigh the risks and benefits of every medical treatment, especially surgical procedures. 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 surgery 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. Older adults with new or worsening cognitive decline often struggle to understand and comply with prescribed physical and occupational therapy sessions in senior rehab.

Depending on the type of procedure a senior requires, less intense sedation that often comes with fewer side effects may be a better option. Regional anesthesia used in conjunction with a sedative can be a safe and effective alternative to general anesthesia for many surgeries. Recovery time, pain, side effects and costs are often reduced 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 Comprehensive Preoperative Evaluation Is Crucial

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

  • Medication Regimen

    The drugs used in general anesthesia can negatively interact with some prescription medications, including beta blockers, diabetic medications, non-steroidal anti-inflammatory drugs (NSAIDS), opioids, diuretics and psychiatric medications. 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. This will ensure the risks and benefits of the procedure can be weighed properly and that they can provide specific instructions for continuing, tapering off or stopping certain medications.
  • 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 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 to obtain medical clearance for surgery.

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 all ages, but making sure the surgical team is current on an elderly patient’s health status will reduce the risk of adverse mental (and physical) side effects.

Sources: Unique Aspects of the Elderly Surgical Population: An Anesthesiologist’s Perspective (; General anesthesia (; Staying Safe in the Hospital With Parkinson’s Disease (; Delirium or Dementia? (; Seniors and Anesthesia (; Medication and Surgery: Before Your Operation (

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