Memory loss after surgery and anesthesia: what you need to know

Surgery causes stress and puts you in an unfamiliar environment. This can affect your memory, both short-term and long-term. Additionally, anesthesia heavily affects the brain. Unsurprisingly, this combined stress can cause memory problems after surgery. Many patients ask me about memory loss after surgery and anesthesia. This is referred to as "postoperative cognitive dysfunction,"  meaning "cognitive problems after surgery."

Can you prevent memory loss after surgery? We believe so.

What is cognitive dysfunction? How is it different from dementia?

Cognitive dysfunction and dementia are similar. Both result in cognitive impairments, such as problems with reasoning, thinking, and remembering. We typically refer to dementia as a long term disease affecting many brain functions, which can include severe memory loss. Unfortunately, people with dementia may not be able to live alone and take care of themselves.

Cognitive dysfunction is typically less severe than dementia. For example, this could be only minor memory loss after surgery. People with cognitive dysfunction can usually live alone and take care of themselves. Fortunately, cognitive dysfunction and memory loss after surgery can sometimes recover. These patients don't suffer any long term memory problems or dementia from their surgery.

However, in some patients, memory loss after surgery may not recover. Unfortunately, these patients may suffer long-term memory problems. Worse still, some patients need to retire early if their memory problems are severe enough.

How often do patients have memory loss after surgery?

The chance of having memory loss after surgery depends on many factors:

Why does surgery cause cognitive dysfunction?

We don't know why some patients have memory problems after surgery. There are three possible culprits for memory loss after surgery:

The possibilities for cognitive dysfunction after surgery are (1) the surgery itself, (2) the anesthesia, (3) the underlying disease you're having surgery for

1. The surgery: cutting your tissue causes inflammation. Inflammation may contribute to cognitive problems and memory loss after surgery. You can also get disoriented after surgery, being in an unfamiliar hospital with strangers taking care of you.
2. The anesthesia: these medications "turn off your brain" during surgery. We are not aware of any long-term damage from anesthesia medications at this time. We're not yet sure, but this might contribute to memory loss after surgery.
3. The reason you're having surgery: patients don't have surgery for no reason. Whether cancer or heart disease, it is possible that the underlying disease is responsible for the memory loss after surgery.

Does a specific type of anesthesia protect against memory loss after surgery?

The more complex the surgery, the more complex the anesthesia. Unfortunately, this complexity carries higher risk of memory loss, too.

Using local anesthesia (including nerve blocks and epidurals - see my articles) instead of general anesthesia may be safer (see my upcoming article on the difference between local and general anesthesia and which is less risky). This might be because patients are in a "twilight" sleep when they have local anesthesia or sedation. These are less complex surgeries that typically require less anesthesia. These appear to have lower risk for memory loss after surgery. However, we are still researching this topic, and general anesthesia remains incredibly safe (see my upcoming article).

Minor surgeries not requiring hospitalization have lower risk for memory changes after surgery and anesthesia

How can I prevent memory loss after surgery?

Having a pre-surgery consultation with your anesthesiologist is very important. The goal is to achieve your best physical and mental fitness before surgery. Memory loss after surgery might be reduced with this preparation. This usually takes 6-8 weeks and includes discussing:

• Physical activity.
• Social interaction.
• Emotional state. For example, depression and anxiety.
• Medical conditions. For example, diabetes, high blood pressure, heart or lung disease.
• Nutrition.
• Blood tests and other laboratory testing.

Drugs and medications can affect memory loss after surgery

Drug use before and after surgery can significantly impact recovery. This includes alcohol, tobacco, marijuana, and other drugs (see my upcoming articles).

Pain medication before and after surgery can also heavily impact cognitive function. This can also affect pain and anxiety (see my upcoming articles), which can then worsen memory loss.

Unfortunately, anxiety medications can also worsen memory problems after surgery. Always be careful with these drugs: mixing anxiety medication with pain medication can be lethal (see my upcoming article).

Interestingly, higher education appears to keep your brain "healthier". Higher education levels protect you from memory loss after surgery. We are still learning how you can "exercise your brain" before surgery to lessen the risk of memory loss.

Genetic factors are not known to put you at higher risk.

Surgery involves stress, immobilization, and unfamiliar surroundings, all of which have been implicated with deterioration of higher mental functions. -Rundshagen et al.

References

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Freedland KE, Skala JA, Carney RM, et al. Treatment of Depression After Coronary Artery Bypass Surgery: A Randomized Controlled Trial. Arch Gen Psychiatry. 2009;66(4):387–396.

Van Harten, A. E., T. W. L. Scheeren, and A. R. Absalom. "A review of postoperative cognitive dysfunction and neuroinflammation associated with cardiac surgery and anaesthesia." Anaesthesia 67.3 (2012): 280-293.

Brown, Emery N., and Patrick L. Purdon. "The aging brain and anesthesia." Current Opinion in Anesthesiology 26.4 (2013): 414-419.

Newman, Mark F., et al. "Longitudinal assessment of neurocognitive function after coronary-artery bypass surgery." New England Journal of Medicine 344.6 (2001): 395-402.

Kotekar N, Shenkar A, Nagaraj R. Postoperative cognitive dysfunction - current preventive strategies. Clin Interv Aging. 2018;13:2267-2273. Published 2018 Nov 8. doi:10.2147/CIA.S133896

Mason, Sam Ewan, Anna Noel-Storr, and Craig William Ritchie. "The impact of general and regional anesthesia on the incidence of post-operative cognitive dysfunction and post-operative delirium: a systematic review with meta-analysis." Journal of Alzheimer's Disease 22.s3 (2010): S67-S79.

Moran J, Guinan E, McCormick P, Larkin J, Mockler D, Hussey J, Moriarty J, Wilson F. The ability of prehabilitation to influence postoperative outcome after intra-abdominal operation: A systematic review and meta-analysis. Surgery. 2016 Nov;160(5):1189-1201.

Rundshagen I. Postoperative cognitive dysfunction. Dtsch Arztebl Int. 2014;111(8):119-125. doi:10.3238/arztebl.2014.0119

Lori A, et al. Postoperative Delirium and Postoperative Cognitive Dysfunction: Overlap and Divergence. Anesthesiology 2019; 131:477–491