Ok, I'm obviously getting slammed by the Hiroshima nazis, but seriously...
I don't think you can take anything I'm saying as an excuse to pan scan every MVA that comes in, but there IS a gray zone. That gray zone unfortunately, whether you like it or not, includes mechanism of injury. We can all grab as many journal articles as we can to boost our argument, but the fact remains that it's not algorithmic and there is an element of clinical judgement involved. There is also no definitive rule of thumb for just how long is long enough to obs someone in the ED for serial belly exams.
My personal take is that if the pt lost consciousness, the vehicle suffered enough damage (intrusion, etc..) that resulted in a prolonged extraction, and the vehicle flipped and rolled, I would err towards a pan scan unless they just looked virtually untouched. The fact remains though... how long is long enough to obs them in the ED? Should the ED be a holding place for pt's such as this where you've got a surgery/trauma service that won't admit for observation? I would argue no. The ED is not a holding area and I don't want to get really busy 1 hour later with ED resources diverted elsewhere and lose track of the patient.
Our own text argues an even more conservative approach such as serial belly exams by the SAME senior clinician for 16-24 hours. Do we actually do this? Of course not. Does anyone feel like doing this? I sure don't.
Yes, there is radiation exposure. Yes, negative scans make you feel bad for exposing the patient, but honestly... if the majority of my scans are positive, I'm not doing enough of them.
We can all sit here and argue that one particular way is the right way, but there is currently no unified evidence based approach to how to handle those gray area patients. There are multiple guidelines and mechanism of injury should most definitely play a role in the management process of trauma patients IMO.
Personally, I get no push back at all by trauma for observing these patients. Def not in my teaching institution and def not out moonlighting...yet.
Also, I think we all are prone to develop bias based on adverse outcomes. Maybe I'm more sensitive to it but I'll never forget a case where a young adult who was transferred from another hospital for a mechanism even less than this one and had a faint finding on CT A/P (that probably I wouldn't have even done). Looked so well that trauma at this particular place even elected to not re-scan the belly. Serial belly exams normal during obs. Discharged and guy shows up in an ED within the next 12 hours with belly full of blood and dies. Unavoidable? Perhaps. Repeat CT would have probably showed new findings I would think, but again...lots of radiation for a minor finding. We sure aren't perfect, but CT can pick up a lot of stuff that we miss. Radiation or not, it's still the best and fastest imaging study we have in acute trauma. Again, that doesn't mean pan scan everyone but it's not all black and white. As posted above, even the experts are still arguing over how to properly stratify patients for pan CT's.