Last week I attended SUNY’s Faculty Retreat, and one retreat treat was a presentation by Dr. Allen Shaughnessy on Evidence-Based Practice.  He noted the changes in medical information and its application to clinical practice.  To summarize, the amount of information being added to the knowledge base is making it almost impossible to “keep up with the literature.”   Technology has helped to make the information available, but not necessarily more useful.  He presented a model of evidence-based practice based on “patient-oriented evidence that matters (POEMs).” When trying to decide if a piece of literature is worth investing your limited research time, ask yourself these questions:

  • Does the information focus on outcomes patients care about: living longer lives, better lives, or both.
  • Is the intervention feasible and does it address a problem that is common in my clinical practice?
  • Would the information require me to change my clinical practice?

I recently went through a small pile of articles on my desk using this analysis.  I was looking for POEMs.  A few rose to the that standard.  I chose to highlight one because it looks at the issue of iatrogenic (due to the activity of a physician or medical therapy) brain injury and forced me to reconsider a patient that I had written about previously on this blog.  This article is not a double blind clinical trial; it is a thoughtful analysis of animal-based research.

Rappaport B, Suresh S, Hertz S, Evers A, Orser B.  Anesthetic neurotoxicity–Clinical implications of animal models. New Engl J Med 2015;796-7.

Summary: Over the last 20 years, studies have been published that raise concern that general anesthesia causes adverse neurodevelopmental outcomes in these children later in life.  Although observational studies in humans are confounded by multiple factors, these studies suggest that children undergoing general anesthesia early in life have an increased  risk for the development of deficits in learning and school performance.  Animal studies have confirmed that certain anesthetics cause changes to brain biochemistry that produce neurotoxic effects in laboratory animals (apoptosis of neurons and oligodedrocytes).  Studies in non-human primate have demonstrated histological changes and impaired performance on behavioral tests.

Based on the accumulated data, a panel of experts working in conjunction with the FDA produced a new statement recommending that surgical procedures performed under anesthesia be AVOIDED in children under 3 years of age, unless the situation is urgent or potentially harmful if not attended to.

Here is my POEM analysis:

  • Does the information focus on outcomes patients care about: living longer lives, better lives, or both.  YES!  patients and parents want to live better lives by avoiding neurotoxic effects (brain injury) that might cause impaired learning and development.
  • Is the intervention feasible and does it address a problem that is common in my clinical practice?  YES!  patients and parents are seeking to make informed decisions about options in the treatment of strabismus, including surgery.
  • Would the information require me to change my clinical practice? YES! I will include this information when educating the parents of young children when they are considering the options in the treatment of their child’s strabismus.

Now, let’s apply this POEM to clinical practice, so back to my strabismic patient: a 3 year old girl with a large, constant, unilateral exotropia with worsening  amblyopia.  The guidelines refer to children under the age of 3, so would general anesthesia be “safe” in this case?  Is there some sort of switch in the brain that eliminates the risk on a child’s 3rd birthday?  I think not.  There is probably some sort of continuum, with decreasing risk with brain maturation over time. If I was to see this patient tomorrow, I would advise the mother to hold off on strabismus surgery and consider other options.

The experts that developed this statement note the need for more research, looking at age, dosage, cumulative dosage, the role of underlying disease or inflammation that increase the risk of brain damage, and ultimately strategies that might reduce harm.  They had to draw a line in the sand, and they chose 3 years of age, to reduce risks in the most vulnerable population.  I wonder where this might lead if the research is extended to look at elderly populations.   Are older patients who suffer from an acquired brain injury now more susceptible to brain injury from anesthesia?  Is that one of the reasons they often have symptoms so much greater than you might expect from their examination?   Perhaps this has been done and I don’t know because I haven’t looked for it, because I don’t see that many elderly patients in my day-to-day practice.  I know many readers of this blog see elderly patients who have suffered from brain injury…… want to do a POEM analysis for brain injury from anesthesia in elderly populations?  Then again, would it change the way you practice?anesthesia old

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