By Keith Chamberlin, MD, MBA, FASA
Continuing my thoughts on common anesthetic issues, here is one situation I run into on a semi-regular basis. What do you do when patients ask:
“Will undergoing general anesthesia increase my risk of postoperative cognitive dysfunction?” – a reasonable response would be: ‘On average, it is highly unlikely, but not entirely impossible. Furthermore, for reasons that the medical community does not really understand, some patients may experience a long-term alteration of cognitive function.’”[1]
Not very reassuring, is it? Particularly if this question is asked the day or the night before a scheduled surgery, after all the arrangements have been made to have friends and relatives free their schedules (maybe even travel to the patient’s home) to help them and someone has agreed to take care of the dog for a period of time.
But it is an honest answer, given the most recent paper by Pennings, et.al. in the European Journal of Anesthesiology.[2] Now remember this blog post is not an academic review of the literature, but mostly my 40 yr experience in the OR. Patients want as much reassurance as possible. And that is where I tell them we cannot separate out “having anesthesia” from “having surgery.” That is, the stress of surgery alone can be a causative agent in POCD. We think… But no one undergoes a cholecystectomy or any other surgery without anesthesia, be it general or regional or sedation. (Save for few procedures that can be done under local only.) The Pennings paper is the latest try to separate them, but that paper has its own issues.1
And is it more complicated than that! Increasing age, baseline cognitive impairment, and fewer years of education are consistently associated with POCD.[3] Literature describing cognitive impairment dates back to 1888, with Savage commenting: “One or two practical questions arise for the surgeon, one of the most important being whether neurotic inheritance or neurosis in the individual, as proved by previous attacks of insanity, should in anyway affect the prognosis in operations, and to what degree it should interfere with operations of convenience not essential for the prolonging or saving life.”[4] Ok, so that paper discusses insanity, but you get the point. Do we do surgeries of convenience, particularly on patients at risk of POCD? And who’s convenience? It is the patient that should make that decision – but an informed decision.
Our job is to synthesize all the varied papers, the use of BIS monitoring, the depth of anesthesia, the length of anesthesia, the preoperative risk factors, the medications we use, the techniques we use (general, regional ,local, sedation) and all the other factors we still do not know about brain inflammation and response to surgery, and come with a short understandable answer to the initial very reasonable question: “Will undergoing general anesthesia increase my risk of postoperative cognitive dysfunction?”
Try Googling that and printing the results. You will need a ream of paper. So did anyone put together a great meta analysis of this question? Of course. In 2023 Zeng et.al. did such a thing for adults with non-cardiac surgery.[5] It did not fully answer the question – it ranked POCD by exposure to a variety of drugs, most of which could not be used as a sole agent for a general anesthetic, except propofol and des and sevo. Propofol came out the best in that trio, but still not a very satisfactory answer to the pertinent question. A good summary of POCD literature and current thought can be found in a paper in the British Journal of Anesthesia.[6] [7] Brodier et. al. cite references that give some general population percentages: The incidence of POCD in elderly patients at 1 week is 30%, at 3 months is 10–13% and at 1 yr is 1%.6 But that is not specific to your patient talking to you preop.
And how do you define POCD anyway? By neuropsychiatric testing, or by someone saying “my wife was just not the same after her last surgery…”? Now, our field has many experts talking about POCD, but patients do not want to listen to hours of lectures they will not understand – they want your opinion, doctor. So what do you say?
I tell them it is unlikely. The literature supports that. If they have risk factors I explain the risk is somewhat higher – there are no percentages or numbers to quantify risk or even to quantify the amount or quality of POCD for a given patient. But I can tell you that hernia will not go away by itself, and eventually it will lead to an incarcerated bowel and you will need emergent surgery and that involves a lot more surgical stress than a straightforward elective repair right now. You get this point also – medicine is a specialty of risk/benefit, and all you can do is explain that as clearly as possible. Then it is up to the patient to make the proper decision.
I have never had a patient refuse surgery and anesthesia after an explanation like that – they are extremely appreciative that I took the time to explain the situation. They want to make sure I do not give them “too much anesthesia.” I explain that as anesthesiologists we are highly trained to not give them too much, but not too little. That statement works. What do you do when you are asked this question? I look forward to your thoughts.
[1] Longrois, Dan; Kubis, Nathalie; Holcman, David. How should clinicians interpret these results?. European Journal of Anaesthesiology 42(5):p 385-388, May 2025. | DOI: 10.1097/EJA.0000000000002165
[2] Pennings CH, Van Boxtel M, De Korte-De Boer D, et al. Anaesthesia as a risk factor for long-term cognitive decline. Eur J Anaesthesiol 2025; 42:468–477.
[3] Evered, Lisbeth A. PhD*,†; Silbert, Brendan S. MB, BS*,†. Postoperative Cognitive Dysfunction and Noncardiac Surgery. Anesthesia & Analgesia 127(2):p 496-505, August 2018. | DOI: 10.1213/ANE.0000000000003514
[4] Savage GH. Insanity following the use of anaesthetics in operations. BMJ. 1887;3:1199–200.
[5] Int J Surg 2023 Jan 27;109(1):21–31. doi: 10.1097/JS9.0000000000000001[1]
[6]Postoperative cognitive dysfunction in clinical practice Brodier, E.A. et al. BJA Education, Volume 21, Issue 2, 75 – 82