title: Mixed integer programming model for optimizing the layout of an ICU vehicle.
abstract: BACKGROUND
  This paper presents a Mixed Integer Programming (MIP) model for designing the layout of the Intensive Care Units' (ICUs) patient care space. In particular, this MIP model was developed for optimizing the layout for materials to be used in interventions. This work was developed within the framework of a joint project between the Madrid Technical Unverstity and the Medical Emergency Services of the Madrid Regional Government (SUMMA 112).
  
  
  METHODS
  The first task was to identify the relevant information to define the characteristics of the new vehicles and, in particular, to obtain a satisfactory interior layout to locate all the necessary materials. This information was gathered from health workers related to ICUs. With that information an optimization model was developed in order to obtain a solution. From the MIP model, a first solution was obtained, consisting of a grid to locate the different materials needed for the ICUs. The outcome from the MIP model was discussed with health workers to tune the solution, and after slightly altering that solution to meet some requirements that had not been included in the mathematical model, the eventual solution was approved by the persons responsible for specifying the characteristics of the new vehicles. According to the opinion stated by the SUMMA 112's medical group responsible for improving the ambulances (the so-called "coaching group"), the outcome was highly satisfactory. Indeed, the final design served as a basis to draw up the requirements of a public tender.
  
  
  RESULTS
  As a result from solving the Optimization model, a grid was obtained to locate the different necessary materials for the ICUs. This grid had to be slightly altered to meet some requirements that had not been included in the mathematical model. The results were discussed with the persons responsible for specifying the characteristics of the new vehicles.
  
  
  CONCLUSIONS
  The outcome was highly satisfactory. Indeed, the final design served as a basis to draw up the requirements of a public tender. The authors advocate this approach to address similar problems within the field of Health Services to improve the efficiency and the effectiveness of the processes involved. Problems such as those in operation rooms or emergency rooms, where the availability of a large amount of material is critical are eligible to be dealt with in a simmilar manner.
authors.affiliation: Department of 'Ingeniería de Organización, Administración de Empresas y Estadística', Escuela Técnica Superior de Ingenieros Industriales, Universidad Politécnica de Madrid, Madrid, Spain. javsanchez@etsii.upm.es
authors.forename: Javier Sánchez
authors.initials: JS
authors.lastname: Alejo
authors.forename: Modoaldo Garrido
authors.initials: MG
authors.lastname: Martín
authors.forename: Miguel
authors.initials: M
authors.lastname: Ortega-Mier
authors.forename: Alvaro
authors.initials: A
authors.lastname: García-Sánchez
mesh_terms: D000552:Ambulances / Q000458:organization & administration*; D004632:Emergency Medical Services / Q000458:organization & administration*; D004867:Equipment Design; D006804:Ergonomics; D006801:Humans; D007362:Intensive Care Units / Q000458:organization & administration*; D013030:Spain