Flow switching device for catheterization with a three way catheter comprising: - a housing (7) having four opening (11, 12, 13, 14); - a first, second and third distal hydraulic conduit (1, 2, 3), originating at the first, second and third opening (11, 12, 13), respectively; - switching means 20 engaging with the housing from obtaining a first operative configuration, wherein the first and thirdopening (11,13) are in communication; a second operative configuration, wherein the second and fourth opening (12, 14) are in communication; a third operative configuration, wherein the first and second opening (11, 12) are in communication; a fourth operative configuration wherein the second and third opening (12,13) are in communication; and - hydraulic bifurcation (17) comprising: a respectiveproximal hydraulic branch (6) originating from said fourth opening (14), a fourth and fifth distal hydraulic conduit (4, 5) originating distally from said proximal hydraulic branch and which are fluiddynamically communicating with respect to each other.