Tag Archives: philosophy

Doctor, I Fell On That Knife! Really!?

I’ve had this mechanism of injury described about once a year for my entire career.

“I was just washing the dishes, and I dropped a knife while I was drying it. When I went to pick it up, I lost my balance and tripped over the rug in front of my sink. Then I fell down on the knife, and there you have it”.

What does it really mean?

First, think about physics. Most knives do not land standing straight up. They don’t even land on their side with the blade side up. They land flat with the sharp side perpendicular to anything that might fall on top of it.

Then think about Occam’s razor. You remember, Sir William of Occam back in the 1300’s. He popularized the principle of parsimony in problem solving. What does this mean? If you have more than one possible explanation (or hypothesis) for an event, the simplest one should be selected. Well, the falling down “hypothesis” is way too complicated.

What does it really mean? Your patient either stabbed themself (most common reason), or they are trying to protect the person who really did it (significant other). What to do? Interrogate them, asking the same thing over and over. Ask for exact details. Ask until the story changes. Have other people ask. Sooner or later, you’ll get the answer you were expecting. Then get the appropriate professionals involved to help with the problem (psych, law enforcement, etc).

Gunshots And CT Scan Of The Abdomen

Abdominal gunshots and CT scanning are usually thought to be mutually exclusive. The usual algorithm generally means a prompt trip to the operating room. But as with many things in the management of trauma, there are always exceptions. The key is to understand when exactly one of those exceptions is warranted.

Exception 1: Did it really enter the abdomen? Gunshots have enough energy that they usually do get inside. However, freaky combinations of trajectory and body habitus do occur. There are three tests that must be passed in order to entertain the possibility that the bullet may not have made it inside your patient: physiology, anatomy, and physical exam. For physiology, the patient must be completely hemodynamically stable. Anatomically, the trajectory must make sense. If the known wounds and angles allow a tangential course make sense, then fine. But if there is a hole in the epigastrium and another next to the spine, you have to assume the bullet went straight through. Finally, the physical exam must be normal. No peritonitis. No generalized guarding. Focal tenderness only in the immediate area of any wounds. If all three of these criteria are passed, then a CT can be obtained to demonstrate the trajectory.

Exception 2: Did it enter an unimportant area of the abdomen? Well, there’s really only one of these, and that’s the area involving the right lobe of the liver and extending posteriorly and lateral to it. If the bullet hole(s) involve only this area, and the three tests above are passed, CT may confirm an injury that can be observed. However, there should only be a minimal amount of free fluid, and no soft tissue changes of any kind adjacent to bowel.

Exception 3: A prompt trauma lap was performed, but you think you need more information afterwards. This is rare. The usual belief is that the eyes of the surgeon provide the gold standard evaluation during a trauma lap. For most low velocity injuries with an easily understood trajectory, this is probably true. However, high velocity injuries, those involving multiple projectiles, or complicated trajectories (side to side) can be challenging for even the most experienced surgeon. Some areas (think retroperitoneum or deep in the pelvis) are tough to visualize completely, especially when there’s blood everywhere. These are also the cases most likely to require damage control surgery, so once the patient has been temporarily closed, warmed and resuscitated, a quick trip to CT may be helful in revealing unexpected shrapnel, unsuspected injuries, or other issues that may change your management. Even a completely unsurprising scan can provide a higher sense of security.

Bottom line: CT of the abdomen and gunshots to that area may actually coexist in some special cases. Make sure the physiology, anatomy and physical exam criteria are passed first. I also make a point of announcing to all trainees that taking these patients to CT is not the norm, and carefully explain the rationale. Finally, apply the concept of the null hypothesis to this situation. Your null hypothesis should state that your patient does not need a CT after gunshot to the abdomen, and you have to work to prove otherwise!

When You Order A Test, Check The Results!

This is one of those rules that seems so obvious. But you would be surprised how many times it’s ignored. Here’s just one example that can go wrong in so many ways:

  • You order a chest xray during a trauma activation for blunt trauma, but don’t view it before the patient is transported to CT scan. 

How this can go wrong:

  1. A very large pneumothorax is present, bordering on a tension pneumothorax. Either the patient must be brought back to the ED or all the equipment needed to insert a chest tube must be taken to CT, which is not an ideal place for this procedure.
  2. The stomach is in the left chest. The patient should have been taken directly to OR. There is no need for CT.
  3. A massive hemothorax is noted. However, blood products have not been ordered and the patient suddenly becomes hypotensive in CT. This is not a good place for resuscitation. And the chest tube problem in #1 applies here, too.
  4. A bullet is plainly seen in the middle of the right chest. This unexpected finding shows that the physical exam (or the history of the event) was inaccurate.

And the list goes on. And this is just one of a zillion possible tests that are ordered every day. In this example, looking at the image is simple in this day and age of having PACS viewers everywhere. However, many tests are not available for hours (coags), or are actually done at a later time (morning hemoglobin). This means more opportunities to miss significant results, and although they may not be as life-threatening as my trauma example, failure to check them can still cause significant problems.

Bottom line: Always review the result of every test you order, on every patient. In this age of shift work and work hour restrictions, a good hand-off to other trauma professionals is very important. You must make sure that somebody sees that result in a timely manner soon after it is available. 

Corollary: If you really don’t need to see that result (i.e. it’s not going to change your care anyway), you shouldn’t have ordered the test!

Related post

Why People Don’t Change Their Minds Despite The Data

Has this happened to you?

Your (emergency physician / neurosurgeon / orthopaedic surgeon) colleague wants to (get rib detail xrays / administer steroids / wait a few days before doing a femur ORIF). You question it based on your interpretation of the literature. You even provide a stack of papers to them to prove your point. Do they buy it? Even in the presence of randomized, double-blinded, placebo-controlled studies with thousands of patients (good luck finding those)?

The answer is generally NO! Why not? It’s science. It’s objective data. WTF?

Sociologists and psychologists have shown that there is a concept that they call the Backfire Effect. Essentially, once you come to believe something, you do your best to protect it from harm. You become more skeptical of facts that refute your beliefs, and less skeptical of the items that support them. Having one’s beliefs challenged, even with objective and authoritative data, causes us to hold them even more deeply. There are plenty of examples of this in everyday life. The absence of weapons of mass destruction in Iraq. The number of shooters in the JFK assassination. President Obama’s citizenship.

Bottom line: It’s human nature to try to pick apart a scientific article that challenges your biases, looking for every possible fault. It’s the Backfire Effect. Be aware of this built in flaw (protective mechanism?) in our psyche. And always ask yourself, “what if?” Look at the issue through the eyes of someone not familiar with the concepts. If someone challenges your beliefs, welcome it! Be skeptical of both them AND yourself. You might just learn something new!

If A Tree Falls In A Forest…

Time for a little philosophy today. There seem to be two camps in the world of initial diagnostic testing for trauma: selective scanning vs scan everything. I admit that I am one of the former. Yes, the more tests you do, the more things you will find. Some will be red herrings. Some may be true positives, but are they important? Here’s the key question:

“If a tree falls in a forest and no one is around, does it make a sound?”

There is a clinical corollary to this question in the field of trauma:

“If an injury exists but no one diagnoses it, does it make a difference (if there would be no change in treatment)?”

Here’s an example. On occasion, my colleagues want to order diagnostic studies that won’t make any clinical difference, in my opinion. A prime example is getting a chest CT after a simple blunt assault. A plain chest xray is routine, and if injuries are seen or the physical exam points to certain diagnoses, appropriate interventions should be taken. But adding a chest CT does not help. Nothing more than the usual pain management, pulmonary toilet, and an occasional chest tube will be needed, and those can be determined without the CT.

Trauma professionals need to realize that we don’t need to know absolutely every diagnosis that a patient has. Ones that need no treatment are of academic interest only, and can lead to accidental injury if we look for them too hard (radiation exposure, contrast reaction, extravasation into soft tissues to name a few). This is how we get started on the path to “defensive medicine.”

Bottom line: Think hard about every test you order. Consider what you are looking for, what you might find, and if it will change your management in any way. If it could, go ahead. But always consider the benefits versus the potential risks, or what I call the “juice to squeeze ratio.”

Tomorrow I’ll look at some of the “scan all” vs “scan selectively” literature. Which camp are you in?

References:

  • George Berkeley, A Treatise Concerning the Principles of Human Knowledge, 1734, section 45.
  • paraphrased by William Fossett, Natural States, 1754.