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Mass Trauma > Preparedness Tools > Casualty Predictor
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Mass Trauma Casualty Predictor

In the confusion that often follows a mass trauma event, managing a hospital can be challenging. Past mass trauma events show patterns of hospital use. It is possible to estimate initial casualty volume and pattern after a mass trauma event. Public health professionals and hospital administrators can use this information to handle resource and staffing issues during a mass trauma event.

Patterns of Hospital Use

  • Within 90 minutes following an event, 50-80% of the acute casualties will likely arrive at the closest medical facilities.
    • Other hospitals outside the area usually receive few or no casualties.
  • The less-injured casualties often leave the scene under their own power and go to the nearest hospital. As a result:
    • They are not triaged at the scene by Emergency Medical Services (EMS). 
    • They may arrive to the hospital before the most injured.
  • On average, it takes 3-6 hours for casualties to be treated in the emergency department (ED) before they are admitted to the hospital or released.

Casualty Predictor

When trying to determine how many casualties a hospital can expect after a mass trauma event, it is important to remember that casualties present quickly and that approximately half of all casualties will arrive at the hospital within a 1-hour window.

  • This 1-hour window begins when the first casualty arrives at the hospital.
  • To predict the total number of casualties your hospital can expect, double the number of casualties the hospital receives in the first hour. 

Casualty Predictor

Total Expected Casualties = (Number of casualties arriving in one hour window) x 2 

Note: The total expected number of casualties will be an estimate. There are many factors that may affect the accuracy of this prediction such as: transportation difficulties and delays, security issues that may hinder access to victims, and multiple explosions or secondary effects of explosion (such as a building collapse). 

Figure1: Predicted Emergency Department Casualties: The chart shows the predicted percent of casualties arriving at the emergency department after a mass trauma event over time.  Half of all initial casualties will arrive at the emergency department over a one-hour period.

Page content last revised 3/17/03.


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