EMS vs. POV in Urban Penetrating Trauma

TacMed USA Commentary

Paul Strauss MD

Why MCI Changes the Equation

I agree with the fundamental premise: for a victim with life-threatening penetrating trauma, getting that patient to definitive surgical care as rapidly as possible is critical. Unnecessary interventions at the scene should never delay a patient who needs an operating room.

However, I think we need to be careful about what these studies actually demonstrate—and what conclusions we draw from them.

Zafar et al. examined 74,187 gunshot-wound patients and found that patients transported by EMS had approximately twice the adjusted odds of death compared with patients arriving by private vehicle. Wandling et al. subsequently examined 103,029 penetrating-trauma patients and similarly found an association between private-vehicle transport and lower mortality. More recently, Ferguson et al. examined 69,092 trauma patients in Michigan and again reported increased adjusted mortality among EMS-transported patients.

Those findings deserve attention. But association is not the same as causation.

These are observational studies, not randomized trials assigning comparable trauma patients to an ambulance or private vehicle. The decision to call an ambulance is not random. Patients transported by EMS may differ from privately transported patients in ways that statistical adjustment cannot completely eliminate. The sickest patient lying unconscious in the street is much more likely to have someone call 911, while a patient who is awake and mobile may be placed directly into a car. Injury Severity Score and other statistical adjustments can reduce that bias, but they cannot necessarily eliminate it.

Zafar et al. themselves were appropriately cautious, concluding that mortality may be higher among EMS-transported gunshot victims and that additional study was necessary. The study demonstrated an association; it did not establish that EMS transport caused those deaths.

There is also an important clarification regarding the Wandling study. The adjusted finding was that private-vehicle patients had lower odds of mortality than ground-EMS patients (OR 0.38; 95% CI 0.31–0.47). The study concluded that ground EMS was not associated with improved survival compared with private transportation in urban penetrating trauma. That is different from proving that EMS itself causes mortality.

Most importantly, these studies answer a different question from the one we face during an Active Shooter/Mass Casualty Incident.

They essentially ask: For an individual trauma patient, is mortality associated with the method by which that patient reaches a trauma center?

An MCI requires us to answer a much larger systems question: How do we rapidly get multiple critically injured patients to definitive care without overwhelming the finite resources of any single hospital?

That distinction is critical.

A Mass Casualty Incident exists because the number and needs of casualties exceed the resources immediately available. That resource limitation doesn't disappear when the ambulance or police car leaves the crisis site. It simply moves downstream.

Hospitals also have finite resources: emergency department capacity, trauma bays, operating rooms, trauma surgeons, anesthesiologists, nurses, ventilators, blood products, imaging capability, ICU beds, and other resources necessary to provide definitive trauma care.

Imagine 15 victims with penetrating trauma at an active-shooter incident. Police officers understandably want to save lives, so victims are rapidly placed into patrol vehicles and everyone drives independently to the nearest Level I trauma center.

That may dramatically decrease transport time.

But what happens when 15 patients arrive almost simultaneously and only a limited number can immediately receive blood, trauma-team resuscitation, or go to the operating room?

Meanwhile, another Level I or Level II trauma center may have available trauma teams, operating rooms, anesthesiologists, blood products, and ICU capacity.

We may have shortened the patient's trip to a hospital while actually increasing the patient's wait for definitive care.

That is why I don't believe the appropriate lesson from these studies is simply: "EMS transport takes longer, therefore penetrating-trauma victims should be placed in police cars."

There is another important limitation when applying this literature to active-shooter response: private-vehicle transport and law-enforcement transport are not necessarily the same intervention. These studies do not establish that an uncontrolled police-transport strategy during an MCI produces the same survival benefit associated with private transportation in their datasets.

The better lesson is that time matters tremendously in penetrating trauma, and we should eliminate unnecessary prehospital delays while preserving the trauma system's ability to triage and distribute casualties.

I am absolutely in favor of law enforcement transporting a critically injured victim when circumstances dictate it and waiting for an ambulance would create an unacceptable delay. There may be circumstances where the fastest route to survival really is the back seat of a police car.

But transporting one critically injured patient and managing the transportation of 10, 20, or 50 casualties are fundamentally different problems.

During an MCI, the objective cannot simply be getting everyone to a hospital as quickly as possible.

It has to be getting the right patient to the right hospital—with the resources available to provide definitive care—as quickly as possible.

Speed saves lives. Coordination saves lives too. Without both, we risk simply moving the Mass Casualty Incident from the crisis site to the front door of the closest trauma center.