Triage Study Challenges Notions of Disaster Response

In the face of terrorism and catastrophic natural disasters, modern regional trauma systems that improve survival for critically injured patients are more vital than ever. Yet many fundamental assumptions underlying these systems-such as the notion that it is imperative to send the sickest patients to the hospital first-have rarely been subjected to rigorous scientific scrutiny. Now, for the first time, researchers at NewYork-Presbyterian Hospital/Weill Cornell Medical Center have created a computer simulation model of trauma system response to mass casualty incidents involving dozens or hundreds of injured victims.

The study shows that the best response depends more on the capability of regional hospitals to treat critically injured victims than on the ability to accurately identify those victims in the field.

"There's been the notion gleaned from prior studies that 'overtriage'-letting some people into emergency care who might not actually need it-usually ends up costing lives, with deaths rising as overtriage rates increase. But our new model demonstrates that overtriage alone is unlikely to be the culprit," says lead researcher Dr. Nathaniel Hupert, assistant professor of public health and medicine at Weill Cornell Medical College and assistant attending physician at NewYork-Presbyterian Hospital/Weill Cornell Medical Center.

Instead, levels of overtriage can be beneficial, harmless or detrimental, depending on complex factors included in the researchers' model, he says. Those factors include the capacity of medical facilities to deal with the wounded and the time it takes to process and care for patients.

"No triage system is 100-percent accurate, so the key issue to define from an outcomes perspective is, 'How good is good-enough?'" Dr. Hupert says. "Our study suggests that pre-disaster planning can begin to address this question systematically, using modeling that takes into account local resources and response times, as well as specific types of mass casualty events."

The study is published in a special October supplement on mass casualty incidents of the journal Disaster Medicine and Public Health Preparedness, which focuses on the Virginia Tech shooting.

According to Dr. Hupert, experts in the field of traumatology and disaster preparedness have tended to rely on historical or anecdotal evidence to describe the downside of overtriage. "A number of studies released over the past decade have bolstered the notion that overtriage stretches limited medical resources during mass casualty events and ends up costing lives," Dr. Hupert says. "This was thought to happen in a linear fashion: More overtriage, more unnecessary deaths."

Overtriage can be valuable, however, because it helps ensure that critically injured people who do require speedy, lifesaving care aren't missed. In fact, guidelines from the American College of Surgeons support a limited amount of overtriage in emergency care.

To determine how much overtriage matters to patient outcomes, Dr. Hupert, along with engineers Eric Hollingsworth and Dr. Wei Xiong, Instructor in the Department of Public Health, created a discrete event simulation model representing the size and type of mass casualty event, the accuracy of field triage, and the treatment capability of the regional hospital trauma system. The model included a number of key variables that had never been brought together in one unified framework.

"We included the ability of responders to triage patients, either in the field or at the site of care; the capacity of local centers to care for incoming wounded and then recycle resources to care for new patients; the time needed to process and treat patients; and the window of time in which it was assumed critically injured patients might die," Hollingsworth explains.