Disposable bag is used to recover body fluids (blood, urine, etc. following drainage). It is positioned in the receptacle. The assembly thus composed allows on one side (output) to connect the pump (manual or electric) via a tube to form the vacuum in the receptacle, and on the other side (input) to connect the trocar via a tube. Once the bag is filled, the bag is closed with its cap, removed from the receptacle and disposed of in a DASRI container provided for this purpose (for incineration).