diagnostic errors

Monday, May 18, 2015

It’s the spectacular play that makes the highlight package on Sportscenter. Fans can be amazed at the amazing catch or incredible shot. But at the end of the day, it’s mistakes that lose games and cost championships. Sometimes, it’s the referee or umpire who misses a call and is blamed for adversity. The solution often offered is technology with instant replay, slow motion and multiple camera angles to oversee what had been judged in the blink of an eye. Victors are those who avoid the most mistakes and take advantage of the errors of their opponents.

It is not widely publicized, but mistakes happen in medicine and at an alarming rate. There is a presumption, by patient and family, that technology decreases the risk of errors and makes for better care. That line of thinking opens a Pandora’s box of wrong. Some doctors feel obligated to order tests to confirm their clinical suspicions. Some suffer from a lack of confidence to stand by their bedside decisions. Others believe that ordering a test will decrease their perceived risk of being sued, the concept of “covering their butt”. And sometimes, tests are ordered because families want the reassurance of technology, since blood tests and x-rays can be tangible proof that all is well…except those tests are only as good as their interpretation, done by a radiologist or pathologist who is an anonymous, faceless provider. All the doctor or patient sees are the results on a computer screen. After all, if it’s in the computer, it must be true.

But mistakes happen and at a relatively high rate. X-ray results aren’t always perfect and different radiologists can interpret the same picture in different ways. When reviewing a radiologist’s reports, the error rate can range between 3 and 3.5%. More complicated studies like CT, MRI and ultrasound can have error rates as high as 7%. Interestingly, if one asks more than one radiologist to read a film, the resulting discrepancy rate can run higher than 30%, meaning they don’t agree with each other a third of the time. But that does not necessarily lead to patient harm, because any test result needs to be interpreted in the context of the bedside assessment of the patient.

The key begins with ordering the test in the first place. There needs to be an expectation that the extra information will be a decision maker for the doctor when it comes to diagnosis and treatment. There needs to be a plan of action for each positive or negative result. Blood tests can be very reassuring when they are normal, except when there are false positives and false negatives. The doctor needs to understand the limitations of each blood test and not be falsely reassured when a test comes back normal, only because it was drawn too early in the disease process…or too late. Imagine taking a pregnancy test immediately after intercourse, knowing that it is too early to turn positive, and yet relying on that result for the next none months.

No matter how much or how little technology is used, getting the right diagnosis is tough. Studies from Johns Hopkins estimate 80,000-180,000 patients in the US are harmed each year because of diagnostic errors. Most happen in the doctor’s office as opposed to the hospital and most are due to a missed diagnosis, rather than a delayed or wrong one. Which brings the discussion back to using technology as a crutch instead of a tool.

Diagnosis is based on history. The patient will tell the doctor what’s wrong if the doctor has time to listen, ask the right questions and interpret the answers. Patients and families are often frustrated when the same questions are repeatedly asked by the person who escorts them to the exam room, the nurse who takes their vital signs and the doctor who seems to be in too much of a hurry to really listen. Each listener can interpret an answer in a different way, and nuance can be helpful in pointing the doctor in the right direction to make a diagnosis. Physical exam is helpful but the guiding light tends to be the history, the old fashioned sitting down and talking to the patient. Diagnosis may be self evident but most often it takes time.

Errors will happen in sports and in the doctor’s office. Minimizing the number of errors should increase the chances of winning; the stakes are just a little higher for the patient. There is an art to diagnosis and technology offers few short cuts. For those who prefer computer algorithms in making a diagnosis, try asking a computer to assess the wife’s face that frowns when her husband minimizes a complaint with that recognition leading to a new line of questioning and perhaps the right answer. Nobody said anything about talking needing words.

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to err is human

Monday, June 30, 2014

Sometime mistakes come back to bite you and sometimes they don’t. World Cup has become must see TV, even if the match is between two countries most people would not be able to find on a map. But there are three teams on the field, if one counts the referees and while they qualify for the assignment just as much as the teams they officiate, the referees don’t get much love. While the game happens at real word speed, their work is dissected frame by frame in high definition slow motion replay and their missed calls can make or break a match. In the Greece-Costa Rica match a hand ball was missed that could have allowed a penalty kick for Costa Rica and a potential 2-0 lead. At the final whistle, Costa Rica still won the game but in not without the drama of a shootout after an overtime tie.

Medicine is not without its misses. Every patient encounter, from a doctor taking a history and performing a physical examination or interpreting a test, to a nurse injecting a medication, every interaction between a patient and a health care provider can yield an error. The mistake may have huge consequences or not even be recognized and found only at quality assurance review. While the goal is always to make medical care mistake free, the reality is that there is an “acceptable” miss rate in caring for patients.

Radiology is a prime example about why medicine fails perfection. How can an acceptable miss rate for a board certified radiologist be 3%? For residents in training that number climbs to 8% or higher. It has to do with systems and not being able to touch the patient. When a patient sees a doctor and an imaging test is ordered, (an x-ray, ultrasound, CT or MRI), the radiologist does not get much background information. With today’s technology, there is no film to touch and digital images are sent through the internet tubes to be interpreted, perhaps a continent away to be interpreted. Misses don’t necessarily mean that malpractice has occurred and there may be no consequence to the patient. The error might be an incidental finding or it might be a big deal.

Other areas of medicine are ripe for mistake as well. We know that long shifts, sleep deprivation, stressful environments and large patient loads lead to increased risk for error. For that reason, house staff, interns and residents who look after patients in hospitals, have had their work hours adjusted to provide more time away from work. That change has significantly decreased the error rate in diagnosis and treatment but it also increased the number of patient handoffs, increasing that potential for error. While the patient may be in hospital for days on end, the doctors and nurses responsible for their care change two or three times a day. The handoff from one shift to another may fully explain the situation and critical information or planning can be lost. Hospitals have systems to standardize the information transfer but in the end, medical care happens at the bedside and it’s tough to explain the whole situation of patient subtleties and provider gestalt.

And sometimes, too much information to minimize error can lead doctors astray and cause damage to the patient. Just as replay can stop the flow and grind a football or basketball game to a halt, increasing the tech of testing, can potentially yield false positive and false negatives that can damage a patient. For example, if a doctor is worried about appendicitis in and orders a CT scan to help make the diagnosis, the timing must be right. If the CT is done too early and the body’s immune system hasn’t had a chance to develop inflammation, the scan may be read as normal, even if there is an early case of appendicitis…a false negative.

False positive tests may lead the patient down an unwanted road. 3D breast mammography has become the latest tool to look for small cancers. It may be the next best thing but…the test may be so sensitive that it finds lumps so small that may not cause any danger for the patient in their lifetime. Research continues but the test has already been made available.

As long human judgment is involved in medicine, the risk for mistake exists; it will never be zero though that is an admirable goal. The same situation exists is sport. Technology can decrease the human error rate but at the expense of the game.

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