Modelos de simulação para o apoio ao gerenciamento de estoque de hemocomponentes

Abstract

Blood is vital in the daily life of the human being. We often deal with adverse situations that require blood replacement in our body, whether due to surgery, hemotherapy procedures, treatment of chronic diseases or other disorders. Blood replacement is performed according to the blood compatibility between donor and recipient, and with the type of blood components required, according to the diagnosis presented by the patient. Properly managing the production and stocking of blood components is necessary since it is essential to achieve the balance between blood supply and the demand for blood components, both with stochastic behaviors. The system is complex and presents several randomness, which are present in the demand, in the collection or even in the losses presented by the blood products, since they have a very limited useful life. Another important point related to the blood supply refers to the disparity between the rates of blood collection and the demand for it. While the collection presents seasonality, related to the availability of donors and the schedules available for carrying out the procedures; demand, in its turn, is random in nature, with peaks and periods of low need. Therefore, the simulation methodologies are suitable to depict these systems, since they are able to reproduce with reasonable precision the complexities of the stock management, of blood components, and to support the decision-making in that problems. In this work a simulation model was developed to depict the blood supply system for hospitals. The model is able to represent the demand for blood bags of each kind, the replacement of these and the disposal of those due to expiration time. The model is implemented in a simulation software and validated through real data, provided by a large Brazilian blood center. The data, on the other hand, are previously treated considering conventional blood types, hospitals with higher demand, most requested blood groups and cities where patients come from. A simulation-optimization model is also proposed and implemented in the same software used to simulation. The objective of this model is to predict minimum levels of stock, to satisfactorily supply the selected hospitals, from acceptable levels for disposal and stock shortages. The results obtained by the simulation-optimization model show a stock size equivalent to 4 days of adequate consumption to meet the demand, with acceptable levels of losses and ruptures. The replacement point, in turn, presented with an average equivalent of 2 days of consumption