An important part of medical care is the sharing of information. Patients share the history of their current problem (History of Present Illness or HPI) as well as things like their past medical history, their social context, their goals, their fears.  Clinicians share information about the meaning and interrelationship of symptoms, pathologic (abnormal) and physiologic (normal) processes, diagnosis, treatments, prognoses. I see frequent proposals and discussions about how best to share, usually focused on how information is presented.  It is worth stopping for a moment so we can consider what happens after the information is delivered? Does it stick? Or does it roll off?

Stickiness in the world of physics is an interesting and much studied phenomenon. It also makes a decent although imperfect metaphor for medical communication. Things are ‘sticky’ in our physical world because of viscoelasticity and chemical bonds. Can these concepts help us think about getting medical information we offer (in either direction) to ‘stick’ better?

Viscoelasticity.  Viscoelasticity  has two components:

  • Elasticity: the ability of a given material to change shape or flow like a liquid.
  • Viscosity: the ability of a material to stick to itself without coming apart .  

Elasticity matters for ‘stickiness’ because it enables a material to flow into all the nooks and crannies of an object where bonds can form. (See bonds, below.) Water is a very elastic liquid. It flows well and easily penetrates into crevices and gaps. Too well, in many cases, as anyone knows who has not adequately tightened the cap on a liquid before putting it in a backpack or suitcase can attest. But water is not sticky. That is because it’s elasticity is not accompanied by viscosity. Unlike taffy, silly putty, egg whites, or molasses, water does not stick to itself. Instead, it readily comes apart into droplets. (You have surely seen mist made of water but you will never see a mist made of molasses!) 

So, to be sticky, a substance must be two things: flexible and runny and therefore able to penetrate another object, but also strongly self-adherent, not coming apart when stressed.  This viscoelasticity is an important component of stickiness, but it is not sufficient. After a substance penetrates into an object and sticks to itself, it also has to have an affinity for  the object. That is where bonds come in.

Bonds in this setting are generally the result of chemical attractions between atoms, either ionic or covalent. Ionic bonds are the result of an electric attraction between oppositely charged ions.  Sodium chloride (NaCl) or salt is an example. Covalent bonds result from the sharing of electrons between two elements.  carbon dioxide (CO2) and water (H2o) are examples.

So physical stickiness results when a material is soft and flexible enough to flow into crevices, strong enough to hold together, and has a (chemical) affinity for the surface of the material it is infiltrating.

This has been a model I have used at times when talking to residents about presenting medical information in a way that helps it stick.

First, the information has to be flexible and fluid.  It has to be adapted to the circumstances and the patient. Information cannot be presented the same way to a 4 year old, a 21 year old graduate student, a 45 year old immigrant who struggles with English, and an elderly patient with poor hearing and in pain. It may have to be short and simple. It may have to have exquisite detail. It may have to be organized from symptoms to chemistry, or from chemistry to symptoms. It has to have the right sized words, the right speed and pacing, the right volume, and be accompanied by the right facial expressions and body language. It has to be delivered at the right speed and in the right quantity. But it has to flow and shape-shift if it is to get in.

Second, the information has to be strong and internally coherent. It has to be internally consistent and make sense. 

Finally, the patient and the information have to have the ability to bond. The information must find places where it belongs. It must mean something to the patient in terms of needs and goals, not just as information. 

At some level this is silliness, a strained metaphor. But I have found it a useful way to get residents to think about adapting the content they want to provide to the specific patient, making sure it is presented in a way that can penetrate into the nooks and crannies of the patient’s consciousness, and then has meaning and an affinity for the patient’s needs and goals. Otherwise, it surely runs off, like water on a duck’s back.

I leave it to you, dear reader, to apply this metaphor in reverse, to the ways a patient can make information sticky for the clinician. Post your ideas in the comments below. (Registration required.)


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