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Enlisting virtual victims to test triage systems

Medicine@Yale, 2009 - Jan Feb


Dominique Larrey, the chief surgeon of Napoleon’s armies and a pioneer of military medicine, knew something of mass casualties. In the early 19th century, while accompanying Napoleon on his various campaigns, Larrey devised rules of triage (from the French trier, “to select” or “to sift”) by which soldiers needing medical attention were sorted according to the severity of their injuries, regardless of rank.

Triage is still standard practice in mass-casualty emergencies, often in the form of the Simple Triage and Rapid Treatment (START) system, which assigns color codes to patients depending on their condition. For example, a victim might be color-coded as red, meaning he needs help immediately; yellow, meaning he will need help soon; green, meaning he has minor injuries; or black, meaning he cannot be helped with available resources.

Rules like these help rescuers choose a course of action in chaotic situations. Imagine being the first paramedic on the scene after a tanker truck has plowed into a bus. Traffic is snarled, cars are honking and people are screaming. Who needs attention most—the man on the concrete holding his bloodied knee or the woman on her back with closed eyes? What about the people inside the overturned bus? And what is that white vapor drifting from the truck’s tank?

Yet although rules of triage exist to help rescuers, it is difficult to evaluate whether those rules actually save lives. Though the START system is decades old, says David C. Cone, M.D., associate professor of surgery and of epidemiology, “we have no idea if it works.”

Cone, director of the Division of Emergency Medical Services (EMS) in the medical school’s Section of Emergency Medicine, studies how EMS should be deployed after chemical, biological and nuclear terrorist attacks, and he has run disaster simulations at Tweed-New Haven Airport complete with volunteers smeared with fake blood. But triage research is inherently difficult. For one thing, says Cone, “we don’t even know what we want a mass-casualty triage system to do.” Is the best system the one that’s easiest to teach, the quickest to apply or the one that saves the greatest number of lives? The complexities mount when one considers that every disaster is unique, making it almost impossible to compare triage systems in the real world.

While studying in Italy for a master’s degree in disaster management in 2004, Cone saw a virtual reality (VR) simulator used to train firefighters and realized that the software could be adapted for triage research. Developed by the Dutch company E-Semble, the simulator looks like the highly realistic video game Grand Theft Auto. Learners at a laptop “walk around” a vivid scene, assessing and triaging victims. Dangers and distractions, like toxic spills or television reporters, can be added to the scenario. The learners are timed and their actions exported into a database that can then be analyzed. Working with emergency medicine resident John Serra, M.D., and supported by the Centers for Disease Control and Prevention and the Laerdal Foundation, Cone plans to teach paramedic students two different triage systems several months apart, then compare how they did with each system in identical VR scenarios.

“Once we get the software tuned, then we can design the larger studies,” says Cone, who plans to use the tool to explore whether rules for triage are even necessary, or whether experienced rescuers are better off relying on their accumulated clinical wisdom.

One day, VR tools may allow triage researchers around the world to collaborate, exchange scenarios and compile “libraries” of standardized victims. Cone hopes his work with controlled VR environments will allow for real progress in triage research and ultimately save more lives during real disasters.

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