When you are told you need surgery, there is a lot to think about. What kind of surgery, and what is the recovery like? Will you need to spend time in the hospital? You need to know the risks and benefits of the procedure to make a decision. However, many people don’t consider the anesthesia. How likely are you to suffer post-operative cognitive dysfunction from the anesthetic?
Does Anesthesia Cause Cognitive Difficulties?
Q. Recently, two family members underwent surgery. Although the surgeries were different, the family members experienced similar unexpected complications upon awakening. They suffered hallucinations, memory impairment and cognitive difficulties after anesthesia.
I did some independent research and found that this can happen. Sometimes the memory is regained and the person completely recovers. Other times the person never completely regains full cognitive function. Are some anesthesia drugs more prone to cause this than others?
What Is Post-Operative Cognitive Dysfunction?
A. Doctors have an acronym for this condition: POCD (post-operative cognitive dysfunction). It is most common in the days and weeks immediately following surgery, but even months later some people have measurable cognitive decline (Kotekar et al, Clinical Interventions in Aging, Nov. 8, 2018).
Propofol May Be Better:
It can be difficult to compare different anesthesia protocols. However, a recent prospective randomized controlled trial of 164 patients found that propofol was less likely to cause post-operative cognitive dysfunction than either midazolam or dexmedetomidine (Li et al, China Medical Journal, Jan. 30, 2019). A review of the available research compared intravenous propofol to inhaled anesthetics (Miller et al, Cochrane Database of Systematic Reviews, Aug. 21, 2018). The authors bemoaned the lack of high-quality research. Nevertheless, they concluded that propofol may offer an advantage for reducing POCD. They point to 11 trials currently underway, with hopes that they will provide better data on this important question.
A Test to Predict Post-Operative Cognitive Dysfunction:
Many older people are nervous about undergoing procedures that require general anesthesia. They worry that they will experience cognitive decline as a result. This is not an idle concern. Approximately half of apparently normal seniors do report difficulties with attention or memory following surgery.
Now scientists at Duke University have developed a test that can predict who might be most likely to experience cognitive difficulties (British Journal of Anesthesia, Dec. 12, 2023). According to the researchers, the closest association is with pre-existing cognitive impairment. People who were unaware of their own mild cognitive difficulties prior to surgery may become quite distressed when these suddenly become more apparent following the operation.
The Duke researchers report that a quick pre-operative EEG in which patients are asked to close, then open, their eyes is revelatory. The EEG measures brain reactivity and predicts who is most likely to have post-op problems. The study did not suggest an intervention to reduce the risk of post-operative cognitive dysfunction, but that should be the next step.
Readers Weigh In:
We have heard from some readers who conclude on the basis of their experience that propofol is less likely to lead to post-operative cognitive dysfunction. Here is one example.
Q. After reading your column on the aftereffects of anesthesia, I want to share my own experience.
I had severe memory lapses for months after undergoing anesthesia. It was like knowing something was in a filing cabinet, but not being able to see what is in the folder. It is frustrating to know the information is there, but you can’t access it.
Thankfully, my brain function did return to normal, but it took months. My physician suggested propofol for future surgeries. I have needed anesthesia a few more times over the last several years and have not experienced aftereffects again.
A. Post-operative cognitive decline is surprisingly common, though the cause remains controversial. Propofol is an injectable anesthetic. One study showed less impairment among patients getting propofol compared to those getting the inhaled anesthetic sevoflurane (Hussain et al, Clinical Interventions in Aging, online Sept. 24, 2014).
It makes sense to ask the surgeon ahead of time if a peripheral nerve block would be appropriate. In some cases, such as knee surgery, that may be another option (Liu et al, Clinical Interventions in Aging, online Feb. 18, 2014).
People who find that they are spacey or forgetful after surgery should be patient with themselves. In most cases, the cognitive problems (which may also be linked to insomnia) will disappear over time.
Does the Doctor Use a Brain Monitor?
We heard from Barry in Corona del Mar, CA:
“Anesthesia providers can only guess how much anesthetic you might need. Without a brain monitor, one American patient dies every day from anesthesia over medication. Prior to 1996, to insure an adequate experience, we tend to err on the side of too much. Since the FDA approval of the BIS brain monitor, it is now not only possible but also highly desirable to directly measure individual response to avoid brain fog (aka post-operative cognitive dysfunction or POCD). Watch You Tube Going under with Goldilocks anesthesia. Learn what you need to know by reading ‘Getting Over Going Under.’ Complimentary copies from drfriedberg@drfriedberg.com. DISCLAIMER: Neither I, nor my non-profit Goldilocks Anesthesia Foundation, receive financial support from makers of the BIS monitor.”
