In next week’s podcast I am going to talk about errors and the common reasons why mistakes are common in clinical care. Today I just want to talk about one cause, misperception.
Misperception is a very very common cause of error, and unfortunately a frequent cause of serious error. This occurs when the care provider does not correctly perceive the true state of the patient. There are many reasons why this happens.
First, the provider may not have enough experience to recognize important cues to the patient’s condition. For instance, they may be taught that MI presents as crushing chest pain radiating to the jaw and left arm, but they are not taught that the presentation of MI is very very variable. Therefore when they see a patient with shortness of breath, and maybe a history of COPD, they immediately attribute the dyspnea to the pulmonary disease and proceed down that treatment path.
Second, they may have what is called “buggy knowledge” (rules or heuristics that they create that are simply incorrect). Examples are: all fever on the first post-op day is from atelectasis, or all post-op patients are wet and need diuretics. They may have been taught sloppily, or may have come up with these rules on their own based on insufficient data.
Third, they may be rushed and do not carry out their evaluation in a systematic fashion. In those cases, they may hurry through their history taking and/or their physical exam (or skip it entirely) thinking that they know what is going on and dont need any more data.

So how do you protect against these perception errors? Well, unfortunately experience is the best treatment. Once you have seen the many ways that serious conditions can present themselves, you gain respect for unusual presentations, and cast your diagnostic net wider when evaluating the patient. You also get confirmatory or “rule-out” labs and studies more often (“yeah, he looks OK but get a blood gas and a chest x-ray anyway, we want to be sure. I once saw a guy who looked just like this have a fatal PE”).
But one thing that can be done is to avoid teaching providers absolutes (things always look like this or that). You need to stress that medicine is a very inexact science, especially outside of the hospital where the whole gamut of labs and studies are not available, and where decisions must be made quickly. Also, it is important to stress a bit of fear that you might be missing something. A good maxim to keep in mind is “it is your job to prove the patient is OK, it is not the patient’s job to prove to you that they are sick”. If you keep that in mind, you will go to that extra step to confirm your perception. That extra step can often be the difference between a good and bad outcome.
JY