Primary care is, by nature, inherently less predictable than surgery or construction or piloting a commercial airliner. Beyond patients scheduled for health maintenance visits or chronic care checkups, we are trained to expect the unexpected, never knowing who is going to walk into the door on any given day with a limp, fracture, shortness of breath, chest pain, or other undifferentiated symptom, each with its own particular diagnostic approach. How can we possibly design a checklist for these? Does it even make sense to do so?
Although they probably weren't responding directly to me, family physician John Ely and two colleagues published a fascinating article in the March issue of Academic Medicine that explores the use of checklists to reduce diagnostic errors. They suggest that three types of checklists could help physicians "resist the biases and failed heuristics that lead to diagnostic errors": a general diagnostic checklist, a differential diagnosis checklist, and a disease-specific cognitive forcing checklist. Dr. Ely demonstrates the use of a checklist for the diagnosis of a simulated patient with shortness of breath in this 6-minute YouTube video:
Watching the video, I was first struck by the awkwardness of some of the questions, which ran against the grain of my training. In medical school and residency, I learned that a skilled clinician should perform differential diagnosis much as one would a conversation, keeping the diagnostic possibilities in his or her head and shuffling them in order of likelihood in response to new information. In contrast, Dr. Ely's interview sounds more like something a 3rd year medical student might do - for example, considering heart failure as a possibility when nothing else about the history or examination points toward that diagnosis.
But - notice when he gets to anemia: "Hmm. I didn't think of that." I don't like to dwell on it, but the number of times those words have passed through my head, unspoken, while seeing patients must now number in the thousands, if not tens of thousands. Most of the time, it doesn't matter; common problems are common, and the diagnoses that I arrive at using "cognitive shortcuts" are usually the correct ones. Still, I'm all too aware that after seeing several patients in a row with streptoccocal pharyngitis, every sore throat starts to look like strep, and I might easily misdiagnose the patient who suffers from something else.
Dr. Ely cautions that unlike established clinical decision tools, these diagnostic checklists haven't been prospectively tested for usefulness, an essential step before implementing them into practice. Let's hope that this testing is or will soon be underway. While it's heartening to read in this week's issue of JAMA that, once again, places with more primary care physicians have better health outcomes, it is tantalizing to imagine that we could do even better with checklists.