Optimization models for injured people evacuation in medium/maxi health-care emergencies

We study the problem of injured people evacuation in the case of a medium/maxi health-care emergency such as, e.g., an airplane crash, a maxi-intoxication, or a major car accident, in which many patients are to be simultaneously evacuated, by being assigned to a hospital and to an ambulance, taking into account a color code, denoting their severity, their distances to the hospitals, and the hospital resources and competences. The work is part of the research project DECEMbRIA, funded by the Lombardy Region in Italy and carried out in collaboration with the local emergency service (118). In this paper, we propose a compact integer-linear programming formulation for the problem and show that, by relaxing the integrality constraints of some variables, the formulation still yields integer solutions. We report computational results obtained using both a commercial and a freely available solver.