Most US trauma centers have two tiers of trauma activation. The higher tier is typically called for physiologic derangements like hypotension, tachypnea, or decreased mental status. This triggers arrival of the full trauma team for rapid assessment and management.

The second tier is reserved for patients who may be less seriously injured and usually results in a reduced team. And depending on how good the activation criteria for this tier are, many patients eventually turn out to have no serious injuries and are discharged from the emergency department. This is the purest form of overtriage, and if it occurs frequently, can wear down your trauma team and waste resources.

Criteria for the second tier trauma activation may include mechanism of injury criteria such as ejection, pedestrian struck, intrusion into the passenger compartment, death at the scene, and other similar criteria. They sound like good criteria, but how helpful are they, really? The group at Baylor University Medical Center in Dallas performed a retrospective review of their trauma activations over a one and a half year period to test the efficacy of some of these criteria. They had recently added some mechanism-based criteria to their second tier activations.

Here are the factoids:

• During the study period, they had 1325 second tier activations, and 603 were based on mechanism criteria
• The mean injury severity score of mechanism-based criteria was only 5, versus 10 for anatomic criteria (significant)
• A whopping 37% of mechanistic criteria patients were discharged home from the ED, versus only 10% for other criteria (also significant)
• Second tier activations for physician discretion were just as good as non-mechanism criteria, with an ISS of 10 and 13% discharged home
• Looking at specific criteria, compartment intrusion, ejection, and death in the compartment appeared to be the major overtriage offenders, with an ISS of 5 and 40% discharge rate
• Incidentally, penetrating injury proximal to knee or elbow had very high overtriage rates, with an ISS of 1 and discharge rate of 48%

Bottom line: Trauma centers are encouraged to review their trauma triage criteria periodically, especially when overtriage rates are high. This center is presenting a nice paper that shows the benefit of doing this. They identified four mechanistic criteria that do not appear to be any better than just relying on physician discretion. What they are not saying is that it is probably better to rely on physiologic and anatomic criteria, as well as physician discretion, to determine which level of trauma activation to trigger.

And incidentally, the new ACS highest-level criterion of gunshot proximal to knee or elbow may not be everything its cracked up to be. It’s difficult to say for sure because stabs and gunshots were not separated out in this abstract, and the number they encountered was not specified. But it certainly suggests this criterion needs some fine-tuning as well.

Reference: Intrusion, ejection, and death in the compartment: mechanism-based trauma activation criteria fail to identify seriously injured patients. JACS 225(4S1):S56, 2017.