We need to talk about another elephant in the room. The risks of postoperative delirium and cognitive insult which may present as dementia may be mitigated or even avoided with the right preoperative assessment.
But first, a brief parable by Krylov in the early 1880s, told of a man admiring all the beautiful things in a museum, some “as small as the head of a pin.” A friend familiar with the museum asked him what he thought of the elephant there. The man replied, “Don’t tell anybody—but the fact is that I didn’t notice the elephant!” Remarkably, from this humble origin, the phrase “the elephant in the room,” became a metaphor for a topic of great importance or controversy that everyone seems to know about but is reluctant to talk about due to a sense of discomfort, embarrassment, sadness, or awkwardness.
Table of Contents:
Identifying the elephant
The price that is paid when we actively ignore an important social concern is that it permits cultural blindness to emerge, fostering the status quo and freeing our conscience of any obligation. While there are many examples we could cite, an example of a medical nature is our long failure to acknowledge our concern about children who experienced lethal apneic events at home after uneventful T & A surgery. Another is our long-ignored deficiency of pulse oximetry in detecting occult hypoxemia in patients with dark skin tones. We want to add another elephant in the room: our collective avoidance of acknowledging, measuring, and actively participating in brain health initiatives in our older patients.
We generally avoid admitting we are getting older, often doing what we can to dodge conversations about aging. We may even omit frank discussions with our older patients out of concern that we may offend them. But aging is for real. Consider that in the U.S., those 65 or older are edging towards constituting 20% of the population yet receiving >40% of all surgical services provided yearly. Despite this, there is widespread failure to integrate high-quality published research and evidence-based recommendations regarding promoting perioperative brain health in our older patients. Just one example is that despite a “call to action” by several professional medical societies, preoperative cognitive screening occurs in <10% of at-risk patients undergoing anesthesia, mostly in academic settings. We are reminded of an often-paraphrased axiom, “if it isn’t measured, it can’t be identified or improved.”
Perioperative neurocognitive disorder
Perioperative neurocognitive disorder (PND) is an umbrella term that is subcategorized as:
- Preoperative cognitive impairment
- Postoperative delirium
- Delayed neurocognitive recovery within the first month of surgery
- Serious neurocognitive impairment lasting beyond 30 days
PNDs occur in the setting of surgical stress with older patients particularly vulnerable due to systems-wide, age-related changes. These may include structural and functional alterations in the brain itself. But there is wide variation in cognitive function such that there are: 1) “super-agers” who appear to defy brain aging, 2) those who are average, permitting reasonable function and life quality, 3) those who suffer mild cognitive dysfunction, and 4) those who experience dementia. Even “normal aging” can affect selective cognitive domains like the speed with which we process information, reasoning, and executive function. PND can seriously jeopardize our most basic and cherished faculty: our cognition.
Looking at one syndrome of PND, postoperative delirium, we find evidence that it is associated with a variety of adverse outcomes. It increases hospital length of stay, burdens the economics of care, may lead to institutionalization, and predicts long-term cognitive dysfunction.
Our intent is not to differentiate or detail the nuances of each form of PND. Rather, we wish to acknowledge that some form of PND may occur in over 50% of older patients after major surgery; perioperative modifiers may play a role, and we should be doing more. We also want to draw attention to expert consensus recommendations and interventions that might easily be integrated into your clinical practice.
Actionable targets
Some academic institutions have established formal programs to reduce PND. Here, resources and multidisciplinary teams can be mobilized to prevent or manage the perioperative, neurocognitive challenges that an older patient may encounter. Lessons learned from these programs and basic clinical research offer easy, actionable targets to consider.
Actionable item 1: Remembering what matters to them
Throughout the perioperative period, whenever possible, “lifestyle items,” like glasses, hearing aids, watches, dentures, and any other comfort items, should be with the patient. When appropriate, a family member’s presence can assist in identifying cognitive issues and reorienting the patient to time and place.
Actionable item 2: Optimize drug use as it is a two-edged sword
The Beers Criteria provides a comprehensive list of drugs to avoid or administer cautiously in older patients. The full list can be reviewed, reminding us to be mindful of certain pharmacological considerations such as:
- Avoid combining opioids with benzodiazepines or gabapentinoids; they may be associated with excessive sedation, falls, overdose events, and death.
- Metoclopramide can cause extrapyramidal effects.
- Meperidine is associated with a high risk of delirium.
- Anticholinergic drugs alone or with drug interaction (e.g., promethazine and diphenhydramine) can provoke serious cognitive issues.
- In general, it is best to avoid or minimize the use of anticholinergics.
Actionable item 3: Perform a baseline cognitive assessment
- Failure to benchmark or identify preop cognitive vulnerabilities can lead to increased costs, misdiagnosis, and the loss of valuable information. Many professional societies recommend cognitive screening.
- Knowledge of cognitive status can identify important information regarding the planning of perioperative care.
- Simple assessment tools are available. Most are free and can be administered in 2-10 minutes, require little training, are immediately interpretable, and can be entered into the patient’s medical record.
- The Mini-Cog and Mini-Mental State are good examples.
Actionable item 4: Preserve and encourage physical mobility
Prehabilitation and postop rehabilitation to build strength and vitality and to maintain it can be encouraged by involving physical therapy and nursing staff to get patients active and mobile. Obvious cognitive frailty should trigger a consult.
Actionable item 5: Anesthetic management
It is plausible that there is a wealth of actionable intraoperative targets, given that our drugs temporarily disable the CNS. Yet the most robust, recent literature reveals that the anesthetic type may not greatly influence PND. Rather, there are some general axioms we should adhere to:
- Avoid anesthetic overdose
- Thoughtful minimization of polypharmacy; review the Beers Criteria
- Ensure adequate blood pressure and cerebral blood flow
- Maintain normoglycemia
- Careful use of multimodal analgesia; minimal opioid use
- Maintain normothermia
Final thoughts on dementia and anesthesia
The elephant in the room is large and looming and must not be ignored. Our practice has evolved in a manner that rarely presents follow-up on the patients we care for—usually ending with a handover to the PACU staff. As such, we are largely unaware of the high rates of PND occurring in our older patients. We must be more proactive in dealing with the growing volume of our older patients, starting with routine preop cognitive assessment and its documentation.
As CRNAs ourselves, we understand the challenge of fitting CRNA continuing education credits into your busy schedule. When you’re ready, we’re here to help.
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