Medical Errors And How To Avoid Them

Phil Zeltzman, DVM, talks about some of the different types of errors doctors (and vets) make and how to avoid them.

A medical error is the ultimate taboo. It can bring feelings of shame, incompetence and humiliation. “How Doctors Think” is a fascinating book that investigates the thought process of physicians, through success and failure. Throughout the book, the author, Jerome Groopman, M.D., details different types of errors. Let’s go through a few and apply them to the field of veterinary medicine in general and surgery in particular.

Anchoring Error

Also called distorted pattern recognition, anchoring is “a shortcut in thinking, where a person doesn’t consider multiple possibilities but quickly and firmly latches on to a single one, sure that he has thrown his anchor down just where it needs to be.”

This type of error occurs when we cherry pick symptoms to confirm our (biased) impression.

For example, let’s consider a 6-year-old Labrador whose lameness has been getting progressively worse over the past three months. Of course, we suspect an ACL tear. The fact that he can “sit square” doesn’t seem to matter all of a sudden. The fact that he has no obvious effusion, no stifle pain and no clear drawer sign doesn’t matter either. It must still be a partial tear, we rationalize, without considering hip dysplasia in our differential diagnosis.

Avoid this error by making sure that all of the signs fit with your working diagnosis.

Attribution Error

“Doctors make (…) attribution errors when patients fit a negative stereotype.” Of course, this is more complicated in vet medicine, as we may judge both the owner and the patient. The author recalls a patient that an intern, “filled with a sense of disgust,” suspected of being an unkempt, tired alcoholic. The logical diagnosis would have been cirrhosis. Turns out the patient had copper storage disease.

Vets also may be tempted to neglect a dirty or scruffy-looking patient, or prejudge what a poorly clothed pet owner might be willing to do for their pets.

Avoid this error by not judging a book by its cover. It is clearly not the patient’s fault if he is eaten up by mange or affected by hormonal changes. Our mission is to help him regardless of his appearance.

Availability Error

This refers to the “tendency to judge the likelihood of an event by the ease with which relevant examples come to mind.” In other words, if you see a string of 10 similar cases (pneumonia, SQ lipomas, foreign bodies…), you are more likely to assume that the 11th patient with somewhat similar signs has the same diagnosis. That diagnosis is “available,” it’s familiar, it’s top of mind.

Avoid this error by considering each patient as an individual, independently of previous patients’ diagnoses.

Commission Bias Error

Such an error stems from the tendency toward action rather than inaction. It is more likely to occur with “a doctor who is overconfident, whose ego is inflated.” Ouch!

“But it can also happen when a (doctor) is desperate and gives in to the urge to do something.” This can be caused by a call to action by an impatient client.

This applies to cases where the ideal timing of surgery is unclear, such as gastric dilatation volvulus, a diaphragmatic hernia or a suspected jejunal foreign body. What is more urgent? Stabilizing the patient or performing surgery?

Cutting a patient open is the easy thing to do. Knowing when to cut is an art form.

Satisfaction of Search Error

Surgery lover or not, we can all relate to this situation. The author gives a brilliant analogy. Say you leave your house in the morning. You are preoccupied and in a hurry. You realize that you forgot your wallet. You search in all the usual places, until you find it … on the night stand. Satisfied to have found your wallet, you run out the door, sit at the wheel, when you realize that you also forgot your car keys!

A similar situation can easily occur during the physical exam, an X-ray evaluation (see picture to left) or even in surgery. You are satisfied after finding a gastric foreign body, but “forget” a second one in the ileum. Or you are satisfied after repositioning a bloated stomach and masterfully performing a gastropexy, but unfortunately “forget” to explore the abdomen and remove the gallbladder mucocele waiting to pop (see picture below).

Avoid this error by keeping an open mind and being thorough in your physical, radiographic or surgical evaluation.

Affective Error

This kind of error stems from the desire to “save” a patient we really like from fancy testing, or a client we have bonded with from high expenses.
A case similar to one described in the book could happen to a four-legged patient. Say Dakota, a 10-year-old golden retriever you’ve known for his entire life, comes in for vomiting and lethargy. Stephanie, his owner, is a sweet middle-aged woman who has been an excellent client “forever.” Rather than spending money on blood work, X-rays, endoscopy, biopsies and other crazy options, you opt for symptomatic treatment.

Over the next few weeks, you treat Dakota with a variety of diets, antacids and anti-emetics. But Dakota keeps losing weight.

You finally suggest a work up. An upper GI endoscopy is performed and the biopsies reveal…lymphoma. Weeks have been lost.

Ironic, isn’t it? Our affection for the patient or the client can lead to a medical error that will actually hurt them.

Steer clear of this error by avoiding making financial decisions and by focusing on sound medical recommendations.

Interpretation Error

In radiology, the frequency of disagreement between X-ray readings is surprisingly high.

In one human study at Michigan State University, 60 radiographs were presented to radiologists. The question was simple: “Is this radiograph normal?”
They disagreed with each other in about 20 percent of the cases. This is called “inter-observer variability.”

Worse: When the same radiologists read the same 60 films at a later date, they disagreed with themselves in 5-10 percent of the cases. This is called “intra-observer variability.”

The changes in the pictures were not necessarily subtle. For example, one (human) patient was missing a clavicle, yet 60 percent of the radiologists missed this finding.

Here’s another perturbing finding: “The radiologists who performed poorly were not only inaccurate, they were also very confident that they were right when they were in fact wrong.”

This is certainly not to pick on radiologists. Similar studies have been performed with other specialists.

Moral of the Story

Like it or not, mistakes do and will happen. And notice that none of the mistakes described are due to complete ignorance or gross negligence. They are often related to tricks played by the human mind.

Assuming we can conquer hubris and denial, not doing anything about making mistakes would be irresponsible and unethical. Sure, we can blame ourselves after we make mistakes, but then we should learn from them. Ironically, making mistakes is part of the learning curve.

We should ask ourselves if there is something we could have done differently to prevent the error. We also should ensure that our error never happens again.
Even better: Sharing with others will hopefully prevent them from making the same mistake.

This positive attitude ultimately will make us better doctors or technicians, and will help future patients.

Dr. Phil Zeltzman is a mobile, board-certified surgeon near Allentown, Pa. He is the co-author of “Walk a Hound, Lose a Pound: How You and Your Dog Can Lose Weight, Stay Fit, and Have Fun Together.”


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