Yesterday I had a meeting with the professor of intensive care (an anesthesiologist) at the regional trauma center. We were talking about our favorite topic, trauma. In particular we were discussing the clinical complications, treatments, and outcomes between blunt mechanism trauma patients and penetrating trauma patients along with the latest scientific literature. It was in all respects, a good day.
Today I am back to my normal role of staying out of the way in another service. But one of the things consuming my mind was the effectiveness of massive transfusion in penetrating trauma vs. the outright detrimental results of using it in patients suffering trauma from blunt mechanisms. One of the things that crossed my mind was “how different are the forces involved?” Understanding and promoting the idea of science based medicine, which stipulates potential clinical treatment must meet basic scientific concepts, I decided to start with physics.
The ideal man-killing gun caliber is 7.62mm. At least that is what weapon makers over time discovered. Using this premise I decided to figure out how much energy is involved in blunt trauma. With the help of some online calculators and basic physics, I determined that the average velocity of a 10 gram, 7.62mm projectile is 3,304.0Joules. Comparatively, a 75 kg person moving at 70mph striking a solid object is 36,721.4 joules. Greater than 10 times the energy!
Now it also occurred to me that the surface area of the force transfer along with the vectors of the force transfer in these 2 injury patterns are quite different, and I attempted to math out just how different. Unfortunately, the resources I need are not available to do that right now. (all the docs in this department have to share 1 computer with internet, so I cannot monopolize it for my purposes) But I will get to it.
Now I started the painstaking task of accounting for all of the basic physiology and pathophysiology involved, as well as the various treatments, and it is a work in progress, but the most important “eureka moment” I had on the whole topic was that there is another injury that shares the exact same mechanisms as blunt trauma. That is a burn. High energy, large surface area.
So, I hypothesize, the reason the outcomes of blunt trauma are so poor compared to penetrating trauma is because we attempt to use penetrating trauma treatments on a pathology of completely different mechanisms. Of course it doesn’t work. In the meanwhile, I am going to get back to figuring out how the principles of burn therapy can be applied to blunt trauma… I really don’t foresee ethical approval for an actual experiment on this one though.
I decided to map out some of what I thought were the most important factors. 1st, would be what I call primary ischemia, as far as I know, a term of my own making, but I could be ignorant to other people using it, which would correspond to a vascular inflow-outflow inadequacy. 2nd would be a corresponding inflammatory insult, as is always the case in both shock and trauma. 3rd would be what I describe as secondary ischemic injury, which is microvascular circulation compromise secondary to edema and disruption of the physiologic equilibrium of starlings forces. It has become another one of my rather complex maps. Certainly not fit for inclusion in a textbook. Of all the people who have ever tried or needed to prove something by a math equation, I certainly never considered myself as even remotely the person. I am definitely not capable of doing something like that by myself. I need a friend or coworker who is also an astrophysicist. They are generally good at complex multivariable mathematics…