FP Report -- July 1999
Use analogies to help patients understand medical concepts
SEATTLE -- An analogy is a comparison of something unfamiliar with something familiar in order to explain a shared principle. Or, to use an analogy, it's like a bridge. It spans the gap between what a physician wants a patient to learn and what the patient already knows.
At the Society of Teachers of Family Medicine spring conference, family physician Terry Ruhl, M.D., of Midland, Mich., presented a special session on using medical analogies in patient education.
"Patients often have very little medical knowledge. We're trying to teach them something that maybe took us a couple weeks of medical school to figure out ourselves ... and we're trying to explain it to our patients in a couple of minutes," Ruhl said.
With a volunteer from the audience, he acted out a scenario in which he explained to a patient that she was suffering from hypertension. The patient became confused, asking whether her hypertension had anything to do with her previous diagnosis of anemia. "I just don't understand," she said. "Last month you gave me pills for low blood and now I have high blood. Should I stop those iron pills?"
Then, Ruhl and another volunteer acted out the same scene. This time, however, the physician used medical analogies to help the patient better understand hypertension:
"Hypertension is the same thing as high blood pressure. You see, the heart is like a pump. It pushes blood from one part of the body to another through pipes called blood vessels. When you have high blood pressure, it's like your pipes are too small. The heart has to work real hard and the pressure in your vessels, or the pipes, gets real high. If the pressure gets too high, the pipes will burst. The high blood pressure also damages the pipes when your heart has to work so hard against it. Therefore, it's real important to get your blood pressure down."
When the patient asked about her "low blood," Ruhl used another analogy to explain:
"Your low blood, or anemia, is something completely different. Your blood is like a river, carrying things from one place to another. Oxygen from the air you breathe gets carried in special barges called red blood cells. If you don't have enough of these barges, you can't carry enough oxygen. Your iron pills are letting your body build more red blood cells, or barges."
Studies show that analogies help people understand and retain information, Ruhl said. "One theory is that the analog acts as a framework to organize new information," he said.
Once you've explained that the heart is like a pump and blood vessels are like pipes, patients can use their understanding of pumps and pipes to ask questions. "A patient might ask, 'If the heart's like a pump, what happens when the pump backs up?' And you could then explain that the blood then backs up into the lungs, and we call that congestive heart failure," said Ruhl.
Not all analogies work. Ruhl said a good analogy should have five key characteristics. It should be visual so patients can see it in their mind's eye, illustrative of the concept you're trying to teach, familiar to the patient, clear and short.
In addition to choosing good analogies, also give some thought to whether they are appropriate. Ruhl said physicians should use analogies when the concept is unfamiliar or hard to grasp. Sometimes a medical concept is fairly simple and straightforward, so an analogy would only confuse the patient. Or a patient may have researched the concept extensively already and may not need the comparison.
Ruhl suggested five steps to using analogies:
(1) Determine whether the analogy is necessary.
(2) Check for the patient's understanding of the analog. If the patient isn't familiar with pumps, then your heart analogy won't work.
(3) Explain the analogy. Don't just say, "The heart is like a pump." Explain how the heart is like a pump.
(4) Point out limitations of the analogy, such as, "Of course, your heart is much more complex than a simple pump."
(5) Wean the patient from the analogy. Remember, the analogy is a bridge to understanding the concept. Patients have to cross that bridge.
FP Report is published by the AAFP News Department. Copyright © 1999 by American Academy of Family Physicians.
FP Report | Headlines |AAFP Home | Search