The present application concerns a cannula device for mounting in a base part (9) comprising a housing (Ia, 16) and at least one membrane (4) together defining at least 15 one cavity, the cannula device further comprises a cannula (3) mounted in the housing and being in fluid communication with the at least one cavity, said cannula device is provided with means (5) for attaching the device to the base part (9) on the proximal side of the device.
