The European Project SICMA (Simulation of Crisis Management Activities) provides a modeling of the behavior of the entire Health Service System during field emergency operations, as well as the rules it operates by. The first step toward chain procedure modelling in the management of major emergencies is the representation of a traumatized patient whose health status can be followed in time during simulation. Since management of the trauma patient follows criteria of stabilization of main physiological functions, a trauma patient model was developed based on fundamental pathophysiological functions independently of specific lesion characterization. Methods: Each patient's health status was modelled according to 5 parameters (ATLS): A(airway), B(breathing), C(circulatory), D(disability), E(Exposure). Patient samples are extracted from a 10.000.000 patient database, generated by considering real anatomical lesions compatible with type and severity of considered scenarios (explosion, building collapse, fire, gunfight). Simulated lesion characteristics were then converted to pathophysiological parameters. Each physiological compensation parameter was represented by: (1) baseline value expressed as percentage of altered function; (2) function reduction rate over time, obtained by a mathematical approximation of clinical worsening. From level of function, rate of worsening and function-specific death thresholds, estimated time-to-death according to sustained damage is computed.

This model allows simulation of evolution of patient health status both in absence of medical care, but also under therapy, in terms of immediate increment of each single parameter (“temporary” treatment), and of reduction or zeroing of parameter dec14rement rate (“definitive” treatment).

This model, based on evaluation of physiological parameters, presents an advantage over the consideration of single lesions, because simulating logical procedures that guide treatment choice in real situations can provide a more accurate assessment of casualities for those actors assigned to management of major emergencies.