it is a medical device (1) for percutaneous or venous access for the purpose of administering a fluid to a patient or sampling from one, comprising a body (2) from which emerges a cannula (4) supported on a distal end (7) of a cannula support (8), a proximal end (9) of said cannula support (8) is connected to a tube (10) in which said fluid can circulate, said cannula support ( 8) has the ability to move within said body (2) of the device (1) under the force of a resilient thrust element (26), a part immobilization member (32) with said body (2) and which has the capacity to prevent said movement of the cannula support (8) and is provided with means (24) to activate such movement associated with the body (2) of the device (1) that acts in conjunction with the contrams (35) of a piece with said cannula support (8). said cannula support (8) has a part or portion of cross section which is reduced or different (80) from its said distal end (7) and from its said proximal end (9), said part or portion (80) of section reduced or different transverse allows said cannula support (8) to deform within the body (2) of the device (1) when said activation means are activated and in order to separate said cannula support from said immobilization member (32) and allows the cannula support (8) to move in that body (2) of the device (1) and enter again and disappear within that body (2) of the cannula (4).trata-se de um dispositivo médico (1) para acesso percutâneo ou venoso com os propósitos de administração de um fluido a um paciente ou de amostragem a partir de um, compreendendo um corpo (2) do qual emerge uma cânula (4) sustentada em uma extremidade distal (7) de um suporte de cânula (8), uma extremidade proximal (9) de dito suporte de cânula (8) é conectada a um tubo (10) no qual o dito fluido pode circular, dito suporte de cânula (8) tem capacidade de se mover dentro de dito corpo (2) do dispositivo (1) sob a força de um elemento de empuxo resiliente (26), um membro de imobiliz
